Pesticides in surface drinking-water supplies of the northern Great Plains.
In agricultural landscapes, rural and municipal residents can be exposed to agricultural pesticides either directly during crop applications or indirectly in air, water, or food. In the northern Great Plains of the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. and Canada, pesticides have been detected in atmospheric samples, in surface and groundwaters, and in a variety of food products. Studies in the United States (Garry et al. 1996), Spain (Garcia-Rodriguez et al. 1996), and New Zealand New Zealand (zē`lənd), island country (2005 est. pop. 4,035,000), 104,454 sq mi (270,534 sq km), in the S Pacific Ocean, over 1,000 mi (1,600 km) SE of Australia. The capital is Wellington; the largest city and leading port is Auckland. (Hanify et al. 1981) have shown that environmental exposure to agricultural chemicals is associated with increases in human health anomalies. These include reduced stamina, gross and fine eye- hand coordination, and cognitive abilities in children (Guillette et al. 1998); an increased incidence of human birth malformations (Garry et al. 1996; Hanify et al. 1981; Schreinemachers 2003); and cryptorchidism cryptorchidism /crypt·or·chid·ism/ (krip-tor´kid-izm) failure of one or both testes to descend into the scrotum.cryptor´chid
Cryptorchidism in male children (Garcia-Rodriguez et al. 1996).
Pesticide exposure through potable potable /pot·a·ble/ (po´tah-b'l) fit to drink.
Fit to drink; drinkable.
fit to drink. water has become a concern. Using a statewide survey of 856 Iowa municipal drinking water drinking water
supply of water available to animals for drinking supplied via nipples, in troughs, dams, ponds and larger natural water sources; an insufficient supply leads to dehydration; it can be the source of infection, e.g. leptospirosis, salmonellosis, or of poisoning, e.g. supplies, Munger et al. (1997) compared the rate of intrauterine growth retardation Intrauterine Growth Retardation Definition
Intrauterine growth retardation (IUGR) occurs when the unborn baby is at or below the 10th weight percentile for his or her age (in weeks). in births by women whose drinking water contained higher levels of herbicides [atrazine atrazine
a triazine herbicide; it is not poisonous at levels of intake likely to be encountered in agriculture.
atrazine Toxicology A nonphytoestrogenic herbicide. See Phytoestrogen. , cyanazine, metolachlor, and (2,4-dichlorophenoxy) acetic acid acetic acid (əsē`tĭk), CH3CO2H, colorless liquid that has a characteristic pungent odor, boils at 118°C;, and is miscible with water in all proportions; it is a weak organic carboxylic acid (see carboxyl group). (2,4-D)] with that in births by women using other sources of drinking water. The authors concluded that atrazine, metolachlor, and cyanazine were each significant predictors of intrauterine growth retardation and that areas with drinking water containing higher herbicide herbicide (hr`bəsīd'), chemical compound that kills plants or inhibits their normal growth. A herbicide in a particular formulation and application can be described as selective or nonselective. concentrations had higher rates of intrauterine growth retardation than nearby communities with other sources of drinking water.
In the northern Great Plains of Canada and the United States The United States and Canada share a unique legal relationship. U.S. law looks northward with a mixture of optimism and cooperation, viewing Canada as an integral part of U.S. economic and environmental policy. , drinking water sources include groundwater and large rivers. However, because of inadequate volume or unsuitability of groundwater because of high mineral content, residents of some smaller communities derive their drinking water from small reservoirs with drainage areas imbedded in agricultural landscapes. In a 3-year study, Cessna and Elliott (2004) monitored prairie farm dugouts (constructed ponds) in Saskatchewan for several herbicides used extensively in crop production on the Canadian prairies The Canadian prairies is a large area of flat sedimentary land stretching throughout western Canada between the Canadian Shield in the east and the Canadian Rockies. The Canadian prairies – the portion of the Great Plains landform that supports various grasses and shrubs . Two of these small reservoirs were used by the farm families for drinking water and household water. Herbicides detected in these dugouts were those expected from an agricultural landscape dominated by cereal and oilseed oilseed
the seeds of the linseed plant, rapeseed or canola, peanut, safflower (Carthamus tinctorius); biproduct oils from seeds include corn, grapeseed, olive, sesame, sunflower. production and included 2,4-D, diclofop, bromoxynil, (2-chloro-4-methylphenoxy)acetic acid (MCPA MCPA, MCP
2-methyl-4-chlorophenoxyacetic acid; a weedkiller reported to be nontoxic at the levels likely to be encountered on pasture, though it has killed cattle dosed experimentally with large single doses. ), triallate, dichlorprop, dicamba, clopyralid, and trifluralin trifluralin
a dinitroaniline compound used as a weedicide. Excessive, accidental access causes diarrhea, anorexia, nervousness.
trifluralin Parasitology A dinitroaniline herbicide, which at micromolar concentrations selectively inhibits the . Consequently, we hypothesized that rural populations obtaining drinking water from catchments that are predominantly crop lands may be exposed to relatively high concentrations of pesticides in drinking water. In the present study, we assessed the potential for occurrence of pesticides in drinking water of residents of 15 rural communities situated in the northern Great Plains in Canada (Figure 1).
Materials and Methods
Study sites. The 15 communities, associated drinking water reservoirs, and water treatment plants were in Manitoba, Saskatchewan, and Alberta and had populations ranging from 95 to 10,959 (Table 1). We intentionally selected communities where the source of drinking water in reservoirs was primarily from snowmelt snow·melt
1. The runoff from melting snow.
2. A period or season when such runoff occurs: streams that flood during snowmelt. runoff Runoff
The procedure of printing the end-of-day prices for every stock on an exchange onto ticker tape.
If the "tape is late" then it can take a long time to print off all the closing prices. from crop lands, although occasionally rainfall runoff can also be a significant source of water to these reservoirs. In this region, evaporation evaporation, change of a liquid into vapor at any temperature below its boiling point. For example, water, when placed in a shallow open container exposed to air, gradually disappears, evaporating at a rate that depends on the amount of surface exposed, the humidity exceeds precipitation, and rainfall runoff is a relatively rare event. None of the reservoirs was equipped with a meteorologic me·te·or·ol·o·gy
The science that deals with the phenomena of the atmosphere, especially weather and weather conditions.
[French météorologie, from Greek station, and rainfall data used to assess the occurrence of surface runoff Surface runoff is a term used to describe the flow of water, from rain, snowmelt, or other sources, over the land surface, and is a major component of the water cycle. were from the nearest Environment Canada Environment Canada (EC), legally incorporated as the Department of the Environment under the Department of the Environment Act ( R.S., 1985, c. E-10 ), is the department of the Government of Canada with responsibility for coordinating environmental policies and weather station.
Table 1. Location of the 15 reservoirs, their morphology, and population of associated communities. Site latitude Site longitude Surface Maximum area depth Reservoir N W (ha) (m) Manitoba 1 49[degrees]10'44" 98[degrees]08'09" 29.5 15.0 2 49[degrees]17'21" 98[degrees]37'40" 38.6 11.3 3 49[degrees]12'28" 98[degrees]56'54" 24.1 6.7 4 49[degrees]24'21" 100[degrees]00'47" 0.8 6.6 Saskatchewan 5 50[degrees]54'58" 101[degrees]30'44" 0.8 6.7 6 49[degrees]27'48" 104[degrees]34'44" 11.7 6.6 7 49[degrees]59'10" 105[degrees]00'25" 227 6.4 8 52[degrees]58'46" 105[degrees]28'05" 6.5 5.2 9 49[degrees]36'36" 105[degrees]51'48" 67.0 15.8 10 52[degrees]47'73" 106[degrees]35'65" 1.2 5.5 Alberta 11 52[degrees]13'27" 111[degrees]53'54" 20.7 6.1 12 49[degrees]52'51" 112[degrees]46'48" 40.0 4.0 13 53[degrees]12'53" 113[degrees]02'22" 4.0 4.0 14 52[degrees]28'18" 113[degrees]05'29" 8.0 4.0 15 53[degrees]00'26" 113[degrees]13'32" 1,090 5.5 Mean Storage Drainage depth capacity area Reservoir (m) ([dam.sup.3]) ([km.sup.2]) Pop. (a) Manitoba 1 12.9 3,800 130 6,142 2 3.7 1,419 60.0 775 3 2.3 550 153 676 4 5.1 41.6 7.8 725 Saskatchewan 5 5.3 44.7 5.1 95 6 2.5 290 25.6 105 7 3.3 7,413 64.7 412 8 5.1 330 77.3 957 9 7.8 5,215 39.2 2,483 10 5.5 63.2 3.0 236 Alberta 11 2.5 518 84.0 970 12 2.0 740 15,500 1,669 13 4.0 225 4.0 352 14 4.0 475 620 487 15 3.5 38,800 125 10,959 Pop., population. (a) Storage capacity (in cubic decameters) of each reservoir is design capacity and does not represent the volume of water in the reservoirs during the study.
Sources of pesticides to the reservoirs included snowmelt and rainfall runoff. Pesticides present in the atmosphere due to application drift, postapplication vapor loss, and wind erosion wind erosion n → erosión f del viento of soil also entered the reservoirs through both wet (precipitation) and dry (particulate par·tic·u·late
Of or occurring in the form of fine particles.
A particulate substance.
composed of separate particles. ) deposition. Natural vegetation, which provided some protection to the reservoirs through mitigation of surface runoff and atmospheric deposition, covered [less than or equal to]?10% of the drainage area for each of the selected reservoirs. Because of poor groundwater quality (Corkel et al. 2004), these reservoirs are generally sited to avoid hydrologic recharge from groundwater. Finally, there was no flood irrigation irrigation, in agriculture, artificial watering of the land. Although used chiefly in regions with annual rainfall of less than 20 in. (51 cm), it is also used in wetter areas to grow certain crops, e.g., rice. in any of the catchments, so irrigation runoff would not have been a contributing factor.
Reservoir and water characteristics. The storage capacity of the reservoirs varied from 41.6 to 38,800 decameter dec·a·me·ter or dek·a·me·ter
n. Abbr. dam or dkm
A metric unit of length equal to 10 meters.
Noun 1. (3) with maximum depths that ranged from 4 to 15.8 m (Table 1). Surface areas varied from 0.8 to 1,090 ha, and drainage areas ranged from 3.0 to 15,500 [km.sup.2]. Water temperature profiles from individual reservoirs indicated that, with few exceptions, the water in the reservoirs remained weakly thermally stratified stratified /strat·i·fied/ (strat´i-fid) formed or arranged in layers.
Arranged in the form of layers or strata. during summer.
In midsummer (July 2003), the water in the reservoirs varied in dissolved chemical composition for a wide range of parameters. In general, the order of decreasing cation cation (kăt'ī`ən), atom or group of atoms carrying a positive charge. The charge results because there are more protons than electrons in the cation. concentrations was as follows: calcium (19-111 mg/L) > sodium (11.9-332 mg/L) > magnesium (8.2-82.1 mg/L) > potassium (3.5-19.5). For anion anion (ăn`ī'ən), atom or group of atoms carrying a negative charge. The charge results because there are more electrons than protons in the anion. concentrations, the order was bicarbonate bicarbonate or hydrogen carbonate, chemical compound containing the bicarbonate radical, -HCO3. The most familiar of such compounds is sodium bicarbonate (baking soda). See carbonate. (99-374 mg/L) > sulfate sulfate, chemical compound containing the sulfate (SO4) radical. Sulfates are salts or esters of sulfuric acid, H2SO4, formed by replacing one or both of the hydrogens with a metal (e.g., sodium) or a radical (e.g., ammonium or ethyl). (36-674 mg/L) > chloride (4.9-41.8 mg/L) > fluoride fluoride, a salt of hydrofluoric acid; see hydrogen fluoride. See also fluoridation; fluorine. (0.1-0.32 mg/L) > nitrate (> 0.01-0.33 mg/L). Concentrations of total dissolved solids Total dissolved solids (often abbreviated TDS) is an expression for the combined content of all inorganic and organic substances contained in a liquid which are present in a molecular, ionized or micro-granular (colloidal sol) suspended form. were 140-891 mg/L; dissolved organic carbon Dissolved organic carbon (DOC) is a broad classification for organic molecules of varied origin and composition within aquatic systems. The "dissolved" fraction of organic carbon is an operational classification. Many researchers place the dissolved/colloidal cutoff at 0. , 6.8-20.4 mg/L; total phosphorus phosphorus (fŏs`fərəs) [Gr.,=light-bearing], nonmetallic chemical element; symbol P; at. no. 15; at. wt. 30.97376; m.p. 44.1°C;; b.p. about 280°C;; sp. gr. 1.82 at 20°C;; valence −3, +3, or +5. , 0.02-1.05 mg/L; and total nitrogen, 0.43-1.57 mg/L. Total alkalinity al·ka·lin·i·ty
The alkali concentration or alkaline quality of a substance that contains alkali.
1. the quality of being alkaline.
2. [as calcium carbonate calcium carbonate, CaCO3, white chemical compound that is the most common nonsiliceous mineral. It occurs in two crystal forms: calcite, which is hexagonal, and aragonite, which is rhombohedral. ([CaCO.sub.3])] ranged from 90.6 to 336 mg/L, total hardness from 97 to 515 mg/L (as [CaCO.sub.3]), and ammonia concentrations from 0.016 to 0.308 mg/L. The reservoir waters were slightly alkaline (pH 8.08-9.12). In general, the midsummer concentrations of these water quality parameters in the reservoirs were less than Canadian drinking water guidelines [Canadian Council Canadian Council may refer to:
CCME Cisco CallManager Express (IP telephony)
CCME Churches' Commission for Migrants in Europe
CCME Cleveland Coin Machine Exchange, Inc. ) 1999], although there were exceptions at some sites for total dissolved solids and sulfate.
Water treatment. Water treatment in the communities was generally similar (Table 2). Treatment included pretreatment pretreatment,
n the protocols required before beginning therapy, usually of a diagnostic nature; before treatment.
n See predetermination. aeration aeration /aer·a·tion/ (ar-a´shun)
1. the exchange of carbon dioxide for oxygen by the blood in the lungs.
2. the charging of a liquid with air or gas.
n. and copper sulfate copper sulfate, common name for the blue crystalline heptahydrate of cupric sulfate, in which copper has valence +2. It may also refer to cuprous sulfate (Cu2SO4), in which copper has valence +1. application at some of the smaller reservoirs, alum alum (ăl`əm), any one of a series of isomorphous double salts that are hydrated sulfates of a univalent cation (e.g., potassium, sodium, ammonium, cesium, or thallium) and a trivalent cation (e.g. and/or potassium permanganate potassium permanganate
A dark purple crystalline compound used as an oxidizing agent and disinfectant and in deodorizers and dyes. addition at the treatment plant (to induce precipitation and settling of the flocculent floc·cu·lent
1. Having a fluffy or wooly appearance.
2. Containing numerous shreds or fluffy particles of grayish or white mucus or other material. Used of a fluid such as urine.
3. ), sand filtration, and finally chlorination chlorination Public health Addition of chlorinated compounds to drinking water as disinfectants. Cf Ozonation. prior to distribution to the community. Twelve communities had some form of activated carbon treatment; one community also used membrane filtration in their treatment process.
Table 2. Summary of water treatment used in the 15 communities. Community Aeration Settling Cu[SO.sub.4] KMn[O.sub.4] pond Manitoba 1 2 X 3 X X 4 X Saskatchewan 5 X X 6 X 7 X X 8 X X X X 9 X 10 X X X X Alberta 11 X 12 X X 13 X X 14 X X 15 X Community Activated Lime/soda [CO.sub.2] Flocculation carbon ash (alum) settling Manitoba 1 X X 2 X X X 3 X X X 4 X Saskatchewan 5 X 6 7 X 8 X 9 X 10 Alberta 11 X X 12 X X 13 X X 14 X 15 X X Community Sand Membrane Chlorination Fluoridation filtration filtration Manitoba 1 2 X 3 X X X 4 X X Saskatchewan 5 6 7 8 9 10 Alberta 11 X X 12 X X X 13 X X 14 X X 15 X X X Community [NH.sub.3] Manitoba 1 X 2 X 3 4 Saskatchewan 5 6 7 8 9 10 Alberta 11 X 12 13 14 15 X Abbreviations: [CO.sub.2], carbon dioxide; Cu[SO.sub.4], copper sulfate; KMn[O.sub.4], potassium permanganate; [NH.sub.3], ammonia.
Water sampling. Reservoir water samples for pesticide analyses were collected near the center of each reservoir at a depth of 2 m. In 2003, we collected reservoir water samples every 2 weeks from early May through mid-August to coincide with spring application of herbicides (May to early July) and organophosphorus or·gan·o·phos·pho·rus
organ·o·phos insecticides insecticides, chemical, biological, or other agents used to destroy insect pests; the term commonly refers to chemical agents only. Chemical Insecticides
(mid-to late July). We also collected water samples once before ice formation (October 2003), through the ice in midwinter mid·win·ter
1. The middle of the winter.
2. The period of the winter solstice, about December 22.
1. the middle or depth of winter
2. (January 2004), and after spring snowmelt runoff (April 2004 and 2005). We collected simultaneous reservoir and treated drinking water samples in early July 2004 and 2005. Drinking water samples were collected after water treatment at the beginning of each distribution system where water was first accessed for drinking by the community. Pesticide concentrations in these paired samples were used in a general assessment of pesticide reduction by the water treatment plant associated with each reservoir.
We collected water samples for pesticide analyses in four separate 1-L amber glass bottles, one each for analysis of the acid, neutral, and sulfonylurea sulfonylurea /sul·fo·nyl·urea/ (sul?fo-nil-u-re´ah) any of a class of compounds that exert hypoglycemic activity by stimulating the islet tissue to secrete insulin; used to control hyperglycemia in patients with type 2 diabetes mellitus herbicides, and one for organophosphorus insecticides. The acid herbicide samples were preserved with 2 mL of concentrated, pesticide-grade sulfuric acid sulfuric acid, chemical compound, H2SO4, colorless, odorless, extremely corrosive, oily liquid. It is sometimes called oil of vitriol. Concentrated Sulfuric Acid
, and all samples were maintained at 4[degress]C in the dark until analysis.
Although intense rainfall events are rare in this region, the Pembina River Pembina River can refer to:
1. A catching or collecting of water, especially rainwater.
a. A structure, such as a basin or reservoir, used for collecting or draining water.
b. (7,500 [km.sup.2]), which either incorporates or is near the four reservoirs in southern Manitoba Southern Manitoba is a physically large metropolitan area in the southermost area of the Canadian province of Manitoba. It holds just slightly over 1 million people. Although this surpasses that of Edmonton or Calgary, both of them are located in the Calgary-Edmonton Corridor. , was subjected to an unusually high average rainfall of 133.3 mm during the 15 days before our scheduled July 2005 water sample collection at the end of the herbicide application period. During the same period of the previous year of the study, only 22.3 mm of rain (17% of the corresponding 2005 rainfall) occurred before reservoir and drinking water samples were collected. Normal total precipitation for this 15-day period is 45 mm. The 30-day rainfall in the Pembina River catchment was 61 mm and 201 mm before early July water sample collections for 2004 and 2005, respectively. Mean daily discharge for the Pembina River from 21 June to 5 July was 14.8 [m.sup.3]/sec in 2004 and 47.9 [m.sup.3]/sec in 2005, indicating that the June-July precipitation in 2005 generated significant surface runoff. Therefore, in a separate analysis, we compared concentrations and number of herbicides in drinking water samples for the same four reservoirs with these two precipitation regimes. None of the other reservoirs was subjected to this magnitude of difference in rainfall for June 2004 and 2005. Rainfall data for the Pembina basin were obtained from meteorologic stations with the following latitudes and longitudes: 49[degress]10N, 98[degress]04W; 49[degress]39N, 100[degress]15W; 49[degress]15N, 98[degress]31W; and 49[degress]10N, 99[degress]39W.
Pesticide residue Pesticide residue refers to the pesticides that may remain on or in food after they are applied to food crops. Regulation of pesticide residue in the US analysis. The 45 pesticides and degradation products assessed during the study included 17 acidic acidic /acid·ic/ (ah-sid´ik) of or pertaining to an acid; acid-forming.
adj having the properties of an acid; acid-forming properties. herbicides [2),)4)-D, MCPA, (2-chloro-4-methylphenoxy)butyric acid butyric acid (bytĭr`ĭk) or butanoic acid (by (MCPB), 4-(2),(4)-dichlorphenoxy) butanoic acid butanoic acid, IUPAC name for butyric acid. (2),(4)-DB), (2),(4),(5)-trichlorophenoxy) acetic acid (2),(4),(5)-T), (2),(3),(6)-trichlorobenzoic acid (2),(3),(6)-TBA), benzoylprop, bromoxynil, clopyralid, dicamba, dichlorprop, diclofop, fenoprop, imazamethabenz A and B, imazethapyr, mecoprop, and picloram picloram
a picolinic acid derivative used as a herbicide; causes weakness, anorexia and depression in poisoned animals. ], 8 neutral herbicides (atrazine, butylate bu·tyl·ate
tr.v. bu·tyl·at·ed, bu·tyl·at·ing, bu·tyl·ates
To bring a butyl group into (a compound).
bu , diallate, metolachlor, metribuzin, simazine simazine
a triazine weedkiller that is toxic if livestock are allowed access shortly after the plants have been sprayed. Signs of toxicity include staggering in sheep and colic in horses. , triallate, and trifluralin), 5 sulfonylurea herbicides (ethametsulfuron-methyl, metsulfuronmethyl, thifensulfuron-methyl, tribenuronmethyl, and sulfosulfuron; hereafter In the future.
The term hereafter is always used to indicate a future time—to the exclusion of both the past and present—in legal documents, statutes, and other similar papers. , "-methyl" has been dropped from the formal names of the sulfonylurea herbicides), 2 herbicide degradation products (desethylatrazine and desethylsimazine), and 13 organophosphorus insecticides (azinphos, chlorpyriphos, diazinon diazinon
an organophosphorus insecticide, used in ear tags for cattle and in flea collars and rinses for dogs. Called also dimpylate. See also organophosphorus compound. , dibrom, dimethoate dimethoate
an organophosphorus contact insecticide used principally as a premise spray; capable of causing poisoning. Chronic intake causes salivation and diarrhea in calves. , disulfoton disulfoton
an organophosphorus pesticide. , ethion eth·i·on
A highly toxic, liquid organophosphate pesticide, C9H22O4P2S3.
[eth(yl) + (th)ion-.] , fonofos, malathion, parathion parathion: see insecticide. , phorate phorate
an organophosphorus compound used as an insecticide and capable of causing poisoning. , phosmet, and terbufos).
Acid herbicides, neutral herbicides, and organophosphorus insecticides. We analyzed the acid and neutral herbicide and organophosphorus insecticide insecticide
Any of a large group of substances used to kill insects. Such substances are mainly used to control pests that infest cultivated plants and crops or to eliminate disease-carrying insects in specific areas. water samples at Environment Canada (National Laboratory for Environmental Testing, Burlington, Ontario Burlington (2006 population 164,415) is a city located in the Golden Horseshoe, across Lake Ontario and Burlington Bay harbour from Hamilton, in Halton Region, Ontario, Canada. , Canada). To assess recovery of the pesticides from the reservoir and drinking water samples, we added the surrogate compounds (2),(3)-dichlorophenoxyacetic acid, deuterium-labeled d14-trifluralin, and d10-malathion in acetone acetone (ăs`ĭtōn), dimethyl ketone (dīmĕth`əl kē`tōn), or 2-propanone (prō`pənōn), CH3COCH3 (100 [micro]L)], to the acid herbicide, neutral herbicide, and organophosphorus insecticide water samples, respectively, before sample extraction such that the corresponding concentrations were 20, 46, and 29 [micro]g/L.
Sample extraction. We extracted the neutral herbicide and organophosphorus insecticide water samples (1 L) with dichloromethane. The acid herbicide water samples (1 L) were first acidified acidified /acid·i·fied/ (ah-sid´i-fid) having been made acid. to pH 2 with 50% sulfuric acid and then extracted with dichloromethane.
The neutral herbicide and organophosphorus insecticide extracts were concentrated (~ 5 mL) using Kuderna-Danish evaporation and quantitatively transferred to a test tube; iso-octane (2 mL) was added, and then the sample was evaporated evaporated
reduced in volume by evaporation; concentrated to a denser form. to approximately 1.0 mL using a gentle stream of nitrogen gas. The organophosphorus insecticide extracts were transferred onto silica gel silica gel, chemical compound. It is a colloidal form of silica, and usually resembles coarse white sand. It may be prepared by partial dehydration of metasilicic acid, H2SiO3. Because it has many tiny pores, it has great adsorptive power. (deactivated with 10% water) cleanup columns and eluted with 10% acetone in hexane hexane /hex·ane/ (hek´san) a saturated hydrogen obtained by distillation from petroleum.
n. . The neutral herbicide extracts were transferred onto Florisil (deactivated with 10% water) cleanup columns and eluted with 2% methanol methanol, methyl alcohol, or wood alcohol, CH3OH, a colorless, flammable liquid that is miscible with water in all proportions. Methanol is a monohydric alcohol. It melts at −97. in dichloromethane. Eluates from both cleanup columns were concentrated to 1 mL volume before gas chromatographic chro·mat·o·graph
An instrument that produces a chromatogram.
tr.v. chro·mat·o·graphed, chro·mat·o·graph·ing, chro·mat·o·graphs
To separate and analyze by chromatography. analysis.
The acid herbicide extracts were similarly evaporated and transferred to a test tube and evaporated to dryness using a gentle stream of nitrogen gas; the extract residue was then dissolved in acetone (4 mL). Pentafluorobenzyl bromide bromide, any of a group of compounds that contain bromine and a more electropositive element or radical. Bromides are formed by the reaction of bromine or a bromide with another substance; they are widely distributed in nature. (5% wt/vol in 200 [micro]L acetone), together with potassium carbonate potassium carbonate, chemical compound, K2CO3, white, crystalline, deliquescent substance that forms a strongly alkaline water solution. It is available commercially as a white, granular powder commonly called potash, or pearl ash. (30% wt/vol in 30 [micro]L deionized water Deionized water (DI water or de-ionized water; also spelled deionised water, see spelling differences) is water that lacks ions, such as cations from sodium, calcium, iron, copper and anions such as chloride and bromide. ), was added and the mixture heated at 60[degrees]C for 3 hr to form the pentafluorobenzyl esters esters (esˑ·terz),
n.pl organic compounds synthesized from acids and alcohols, typically possessing fruity aromas. . Iso-octane (2 mL) was added and the reaction mixture evaporated to approximately 1.0 mL using a gentle stream of nitrogen gas. The sample extracts were transferred to silica gel (deactivated with 5% water) cleanup columns topped with anhydrous an·hy·drous
Without water, especially water of crystallization.
adj without water.
containing no water. sodium sulfate sodium sulfate, chemical compound, Na2SO4. It is a white, orthorhombic crystalline compound at ordinary temperatures; above 100°C; it assumes a monoclinic structure, and above about 250°C; it assumes a hexagonal structure. (0.5 cm), the columns eluted with 5% methanol in toluene toluene (tōl`yēn') or methylbenzene (mĕth'əlbĕn`zēn), C7H8 , and the eluate eluate /el·u·ate/ (el´u-at) the substance separated out by, or the product of, elution or elutriation.
The solution of solvent and dissolved matter resulting from elution. concentrated to a 1-mL volume before gas chromatographic analysis.
Gas chromatography-mass spectrometric spec·trom·e·ter
A spectroscope equipped with scales for measuring wavelengths or indexes of refraction.
spec analysis. We analyzed the organophosphorus insecticide and derivatized acid herbicide water sample extracts by gas chromatography-negative-ion-chemical-ionization mass spectrometry mass spectrometry
or mass spectroscopy
Analytic technique by which chemical substances are identified by sorting gaseous ions by mass using electric and magnetic fields. . We used a model 6890 gas chromatograph gas chromatograph
An instrument used in gas chromatography to separate a sample of a volatile substance into its components. interfaced with a model 5973 mass selective detector operated in selected ion monitoring mode (Agilent Technologies This article needs sources or references that appear in reliable, third-party publications. Alone, primary sources and sources affiliated with the subject of this article are not sufficient for an accurate encyclopedia article. , Wilmington, DE, USA) with a DB-5 column (30 m x 0.25 mm i.d.; 0.25 [micro]m film thickness; Agilent Technologies, Palo Alto Palo Alto, city, California
Palo Alto (păl`ō ăl`tō), city (1990 pop. 55,900), Santa Clara co., W Calif.; inc. 1894. Although primarily residential, Palo Alto has aerospace, electronics, and advanced research industries. , CA, USA) with methane as the moderating gas. The neutral herbicide extracts were analyzed with the same instrument in the electron ionization Electron ionization (EI, formerly known as electron impact) is an ionization technique widely used in mass spectrometry, particularly for organic molecules. How it works
The gas phase reaction producing electron ionization is
Quality assurance/quality control measures included a laboratory blank sample (type I water) and two fortified fortified (fôrt´fīd),
adj containing additives more potent than the principal ingredient. laboratory blank samples with every 12 reservoir or drinking water samples. No compounds were detected in the laboratory blank samples. Recoveries for the laboratory blank samples fortified with the 17 acidic herbicides, 8 neutral herbicides, 2 herbicide degradation products, and 13 organophosphorus insecticides (concentrations of 10-150 ng/L) varied from 71 to 124% (n = 36). The laboratory surrogate recoveries for both quality assurance/ quality control and field samples ranged from 72 to 115%.
Sulfonylurea herbicides. We analyzed the sulfonylurea herbicide water samples at the National Hydrology hydrology, study of water and its properties, including its distribution and movement in and through the land areas of the earth. The hydrologic cycle consists of the passage of water from the oceans into the atmosphere by evaporation and transpiration (or Research Centre in Saskatoon Saskatoon (săskətn`), city (1991 pop. 186,058), S central Sask., Canada, on the South Saskatchewan River. , Saskatchewan.
Sample extraction. We passed the reservoir and drinking water samples (500 mL) through solid-phase extraction cartridges under a vacuum of 400 mm of Hg (~ 10 mL/min). The cartridges (Oasis HLB HLB Hong Leong Bank
HLB Hydrophilic-Lipophilic Balance
HLB Horton Lees Brogden Lighting Design (company with studios in New York, San Francisco, Los Angeles, and Boston)
HLB Hotels Licensing Board (Singapore) extraction cartridges; Waters Corporation This article or section is written like an .
Please help [ rewrite this article] from a neutral point of view.
Mark blatant advertising for , using . , Milford, MA, USA) were conditioned sequentially with methanol (10 mL) and then deionized water (10 mL). After sample loading, the cartridges were washed with deionized water (10 mL) and then dried for 1 hr under vacuum. After drying, the cartridge was eluted with methanol (10 mL) and the eluate evaporated to dryness using a stream of dry nitrogen gas (water bath at 50[degress]C). The residue was dissolved in deionized water (1 mL) and transferred to a 2-mL HPLC HPLC high-performance liquid chromatography.
high performance liquid chromatography.
HPLC High-performance liquid chromatography Lab instrumentation A highly sensitive analytic method in which analytes are placed (high-performance liquid chromatography) vial vial
a small bottle. . [Because sulfonylurea herbicides may hydrolyze hydrolyze
to performance hydrolysis. in water, the methanol evaporation and subsequent dissolving of the extract residue in deionized water should be carried out just prior to analysis by liquid chromatography-tandem mass spectrometry (LC-MS-MS).]
Liquid chromatography-mass spectrometric analysis. We used a Waters 2695 Alliance HPLC system with a Waters Xterra Mass [C.sub.18] (100 mm x 2.1 mm i.d., 3.5 [micro]m diameter particle size Particle size, also called grain size, refers to the diameter of individual grains of sediment, or the lithified particles in clastic rocks. The term may also be applied to other granular materials. ) analytical column (both from Waters Limited, Mississauga, Ontario For the First Nation, see .
Mississauga (pronounced: [ˌmɪsɪˈsɑgə] , Canada) which was maintained at 30[degresss]C. Mobile phase consisted of solvent A (90:10 water:acetonitrile acetonitrile /ac·e·to·ni·trile/ (as?e-to-ni´tril) a colorless liquid with an etherlike odor used as an extractant, solvent, and intermediate; ingestion or inhalation yields cyanide as a metabolic product. ) and solvent B (90:10 acetonitrile:water). Both solvents contained 0.1% formic acid formic acid or methanoic acid (mĕth'ənō`ĭk), HCO2H, a colorless, corrosive liquid with a sharp odor; it boils at 100.7°C; and solidifies at 8.4°C;. and 2 mM ammonium acetate Ammonium acetate is a chemical compound with the formula NH4C2H3O2. It is a white solid, which can be derived from the reaction of ammonia and acetic acid. It is available commercially, and depending on grade, can be rather inexpensive. . Isocratic elution elution /elu·tion/ (e-loo´shun) in chemistry, separation of material by washing; the process of pulverizing substances and mixing them with water in order to separate the heavier constituents, which settle out in solution, from the of the column with 70% solvent A and 30% solvent B at a flow rate of 200 [micro]L/min resulted in retention times of 4.81, 5.57, 8.05, 12.41, and 14.22 min for thifensulfuron, metsulfuron, ethametsulfuron, sulfosulfuron, and tribenuron, respectively. All injection volumes were 20 [micro]L.
We quantitated the sulfonylurea herbicides and confirmed their presence using the Waters Micromass Quattro Ultima triple quadrupole A quadrupole is one of a sequence of configurations of electric charge or gravitational mass that can exist in ideal form, but it is usually just part of a multipole expansion of a more complex structure reflecting various orders of complexity. mass spectrometer spectrometer
Device for detecting and analyzing wavelengths of electromagnetic radiation, commonly used for molecular spectroscopy; more broadly, any of various instruments in which an emission (as of electromagnetic radiation or particles) is spread out according to some (Waters Limited) equipped with an electrospray ionization Electrospray ionization (ESI) is a technique used in mass spectrometry to produce ions. It is especially useful in producing ions from macromolecules because it overcomes the propensity of these molecules to fragment when ionized. interface set to positive ion mode. Ionization ionization: see ion.
Process by which electrically neutral atoms or molecules are converted to electrically charged atoms or molecules (ions) by the removal or addition of negatively charged electrons. and MS-MS conditions were optimized by infusing a 0.5-mg/L solution of each sulfonylurea herbicide into the ion source An ion source is an electro-magnetic device that is used to create charged particles. These are used primarily within mass spectrometers or particle accelerators. Mass spectrometry in a 50:50 acetonitrile:water solution with a syringe pump. The (M+H)+ ion for each analyte was selected for fragmentation using the first quadrupole; the second quadrupole, into which argon argon (är`gŏn) [Gr.,=inert], gaseous chemical element; symbol Ar; at. no. 18; at. wt. 39.948; m.p. −189.2°C;; b.p. −185.7°C;; density 1.784 grams per liter at STP; valence 0. gas was introduced, functioned as a collision cell; and the third quadrupole was used to monitor the resulting major fragment ion.
Suitable multiple reaction monitoring transitions were chosen from the product ion scans and were as follows: thifensulfuron, 388.3 to 167.2 atomic mass units atomic mass unit or amu, in chemistry and physics, unit defined as exactly 1-12 the mass of an atom of carbon-12, the isotope of carbon with six protons and six neutrons in its nucleus. One amu is equal to approximately 1. (amu); metsulfuron, 382.3 to 167.2 amu; ethametsulfuron, 411.3 to 196.3 amu; sulfosulfuron, 471.3 to 261.2 amu; and tribenuron, 396.3 to 155.2 amu. Instrument operating conditions have been described previously (Cessna et al. 2006).
Recovery of the five sulfonylurea herbicides was determined from both deionized de·i·on·ize
tr.v. de·i·on·ized, de·i·on·iz·ing, de·i·on·iz·es
To remove ions from (a solution) using an ion-exchange process.
de·i and reservoir water. Water samples (500 mL) were fortified with 5 or 50 ng of each sulfonylurea herbicide dissolved in 100 [micro]L acetonitrile resulting in concentrations of 10 and 100 ng/L, respectively. Mean recoveries of thifensulfuron, metsulfuron, ethametsulfuron, sulfosulfuron, and tribenuron from deionized water ranged from 73 to 84% at 100 ng/L (n = 13) and from 81 to 123% at 10 ng/L (n = 13). Corresponding mean recoveries from reservoir water were 105-115% (n = 10) and 82-108% (n = 10), respectively.
The high recoveries from the fortified reservoir waters may indicate ionization enhancement in the source of the mass spectrometer due to the relatively high content of dissolved organic matter in these waters.
Herbicide recoveries indicated that the solidphase extraction method was effective for both deionized and reservoir waters; when coupled with electrospray ionization MS-MS quantification and confirmation, this method provided reliable recoveries down to 10 ng/L. The instrumental limit of quantification was approximately 20 pg for each herbicide and, assuming 100% herbicide extraction recovery from a 500-mL water sample, was equivalent to a method limit of quantification of 2 ng/L.
Statistical analyses. We performed statistical analyses using Systat, Version 11 (Systat Software Inc., Point Richmond, CA, USA) for t-tests and Primer, Version 5.2.9 (Primer-E Ltd., Plymouth, UK) for principal component analysis (PCA (tool, programming) PCA - A dynamic analyser from DEC giving information on run-time performance and code use. ). In cases where pesticides were not detected, we used values equal to one-half the limit of quantification for statistical calculation and graphic presentation (Gilbert 1987). For the parametric statistical analyses, data were examined for heteroscedasticity (unequal variances) or departures from normality normality, in chemistry: see concentration. , and when found, appropriate transformations were applied before analyses. To examine patterns in herbicide concentration across the northern Great Plains, we performed a multivariate The use of multiple variables in a forecasting model. , PCA. PCAs essentially combine the results of all parameters measured into a two-dimensional space where sample similarities can be highlighted, thus allowing patterns between sets of samples to be recognized. Parameters that are correlated with any apparent patterns can also be identified. We selected p < 0.05 for statistical significance; results are reported as mean [+ or-] 1 SE and actual p-values, unless otherwise noted.
Pesticides in reservoir water. Of the 45 pesticides and degradation products monitored during the study, we detected 2 insecticides, 27 herbicides, and 2 degradation products in water collected from 15 reservoirs (n = 206; Table 3). These included 16 acid herbicides, 6 neutral herbicides, 5 sulfonylurea herbicides, 2 herbicide degradation products, and 2 organophosphorus insecticides. Of the 31 analytes detected, three (2,4-D, clopyralid, and dicamba) were present in the reservoirs at concentrations > 1,000 ng/L. Six additional herbicides (dichlorprop, MCPA, metribuzin, picloram, imazamethabenz A, and bromoxynil) were detected at concentrations > 100 ng/L, with the remainder (22) at concentrations< 100 ng/L. We did not detect 2,4-DB, diallate (cis-and trans-isomers), metolachlor, or the majority of organophosphorus insecticides (azinophos, diazinon, dibrom, disulfoton, ethion, fonofos, malathion, parathion, phorate, phosmet, or terbufos). With few exceptions, pesticides that were not detected are not normally used in the study area.
Table 3. Pesticides and degradation products monitored in reservoir water samples ( n= 206). Herbicide Percent of Detection No. of Maximum samples limit samples concentration with (ng/L) with (ng/L) detection detection 2,4-D 100 0.47 206 1,850 MCPA 99 0.58 205 374 Clopyralid 99 0.59 205 1,050 Dicamba 86 0.73 179 1,040 Diclorprop 82 0.42 171 113 Mecoprop 77 0.50 160 83.1 Bromoxynil 54 0.99 112 384 Ethametsulfuron 35 0.01 73 80.4 Atrazine 27 5.76 48 52.7 Tribenuron 20 0.01 42 30.1 Desethylatrazine 21 26.80 37 (20.8) (a) Picloram 13 0.66 27 457 Imazamethabenz A 13 0.14 27 194 Desethylsimazine 12 148.00 22 (25.3) 2,4,5-T 11 0.39 23 4.18 Sulfosulfuron 10 1.0 21 36.1 Fenoprop 9 0.40 19 5.8 Imazamethabenz B 7 0.09 15 93.5 2,3,6-TBA 6 1.10 12 2.43 Imazethapyr 6 1.20 12 11.0 Thifensulfuron 3 1.0 7 12.0 Butylate 3 55.40 5 (3.12) Metsulfuron 2 1.0 5 2.1 MCPB 2 0.63 5 12.8 Diclofop 2 42.30 4 (4.4) Benzoylprop 1 26.20 2 (1.3) Simazine 1 16.40 2 (13.8) Triallate 1 4.14 2 (3.9) Trifluralin 1 5.15 2 (1.0) Metribuzin < 1 20.7 1 185 Chlorpyrifos 3 (b) 14.80 5 20.1 Dimethoate 1 (b) 25.10 1 (5.98) (a) Values in parentheses are estimates of concentration below the reporting limit. (b) n = 30.
Seven herbicides were consistently present in water samples from the 15 drinking water reservoirs (2,4-D, MCPA, clopyralid, diclorprop, dicamba, mecoprop, bromoxynil; Table 4). Although mean concentrations for these individual herbicides varied across the reservoirs by as much as 20-to 50-fold, a principal component analysis suggested no distinct geographic pattern geographic pattern A general descriptor for lesions in which large areas of one color, histologic pattern, or radiologic density with variably scalloped borders sharply interface with another color, pattern or density, fancifully likened to national boundaries of herbicide concentrations. Samples from all three Canadian prairie provinces Prairie Provinces, Canada: see Manitoba; Saskatchewan; Alberta. showed extensive overlap in the twodimensional pattern (Figure 2), indicating that concentrations in this mixture of seven herbicides are not related to geographic location. Mean total herbicide concentration was not correlated with reservoir storage capacity (r = 0.17; n = 15). Clopyralid, 2,4-D, and MCPA were detected in essentially all of the reservoir samples taken throughout the sampling period, regardless of time of year (Table 3). Dicamba, diclorprop, and mecoprop were detected in > 75% of the samples and bromoxynil in 54%. The overall mean concentrations of these seven herbicides in the reservoirs from May 2003 to April 2004 were, in decreasing order: 123 ng/L 2,4-D, 57 ng/L MCPA, 28 ng/L clopyralid, 16 ng/L dichlorprop, 6.6 ng/L dicamba, 4.4 ng/L mecoprop, and 2.4 ng/L bromoxynil (Table 5; n = 163 samples).
Table 4. Mean total pesticide concentrations (ng/L) and mean individual pesticide concentrations ([+ or -] SD; ng/L) in 15 reservoirs in the three provinces ( n= 163; sample from May 2003 to April 2004). Mantoba Herbicide 1 2 3 Mean total 302 341 274 concentration 2,4-D 88 [+ or -]42 131 [+ or -]47 182 [+ or -] 107 MCPA 80 [+ or -]39 32 [+ or -] 15 47 [+ or -]36 Clopyralid 53 [+ or -]27 64 [+ or -]49 14 [+ or -]4.9 Diclorprop 7.5 [+ or -] 3.5 64 [+ or -]27 7.8 [+ or -]4.6 Dicamba 16 [+ or -] 7.4 15 [+ or -]5.4 5.4 [+ or -]3.2 Mecoprop 4.6 [+ or -]3.6 1.4 [+ or -]0.7 8.2 [+ or -]7.5 Bromoxyni 5.8 [+ or -]4.2 2.0 [+ or -] 1.7 2.6 [+ or -]2.6 Ethametsulfuron 2.6 [+ or -] 1.5 6.3 [+ or -] 7.1 2.0 [+ or -]3.2 Sulfosulfuron 1.4 [+ or -]0.9 ND ND Atrazine 34 [+ or -] 15 13 [+ or -]4.2 4.7 [+ or -]2.1 Tribenuron 0.5 [+ or -]0.3 0.3 [+ or -]0.7 ND Picloram ND ND ND 2,3,6-TBA ND + + 2,4,5-T ND + ND Imazamethabenz A + + + Imazamethabenz B + + ND Imazethapyr ND ND ND MCPB ND + ND Fenoprop ND + ND Benzoylprop ND ND ND Butylate ND ND + Desethylatrazine + + + Desethylsimazine + + + Diclofop ND ND ND Simazine ND ND ND Triallate ND ND ND Trifluralin + ND ND Chlorpyrifos ND ND ND Dimethoate ND + ND Mantoba Saskatchewan Herbicide 4 5 6 Mean total 199 98 316 concentration 2,4-D 46 [+ or -]50 27 [+ or -] 12 254 [+ or -] 142 MCPA 49 [+ or -]41 38 [+ or -]20 15 [+ or -] 9.2 Clopyralid 35 [+ or -]26 9.6 [+ or -]8.3 3.6 [+ or -] 1.4 Diclorprop 19 [+ or -] 17 11 [+ or -]4.6 23 [+ or -]12 Dicamba 7.5 [+ or -] 8.0 1.8 [+ or -] 1.1 6.6 [+ or -]6.6 Mecoprop 3.0 [+ or -]2.5 1.0 [+ or -]0.8 3.8 [+ or -] 1.7 Bromoxyni 4.1 [+ or -]3.4 3.4 [+ or -]5.0 2.1 [+ or -] 1.7 Ethametsulfuron 2.6 [+ or -] 1.5 ND ND Sulfosulfuron 25 [+ or -]8.6 ND ND Atrazine + + + Tribenuron 0.4 [+ or -] 0.3 ND 4.0 [+ or -] 1.0 Picloram ND ND ND 2,3,6-TBA ND ND + 2,4,5-T + + + Imazamethabenz A + ND ND Imazamethabenz B + ND ND Imazethapyr ND ND + MCPB ND ND ND Fenoprop + + + Benzoylprop ND ND ND Butylate ND ND ND Desethylatrazine + + + Desethylsimazine + + + Diclofop ND ND ND Simazine ND ND ND Triallate ND ND ND Trifluralin ND ND ND Chlorpyrifos ND ND + Dimethoate ND ND ND Saskatchewan Herbicide 7 8 9 Mean total 172 498 176 concentration 2,4-D 96 [+ or -]35 121 [+ or -]32 131 [+ or -] 28 MCPA 21 [+ or -]9.7 263 [+ or -] 72 15 [+ or -]3.6 Clopyralid 5.0 [+ or -] 1.6 91 [+ or -]23 2.3 [+ or -]1.0 Diclorprop 26 [+ or -] 10 5.6 [+ or -]2.2 5.2 [+ or -] 1.0 Dicamba 9.3 [+ or -]5.3 1.9 [+ or -] 1.3 14 [+ or -] 3.2 Mecoprop 8.4 [+ or -] 6.1 4.9 [+ or -]2.1 2.8 [+ or -]1.1 Bromoxyni 1.6 [+ or -] 1.4 1.8 [+ or -] 1.6 1.0 [+ or -]0.6 Ethametsulfuron ND 4.9 [+ or -]2.7 ND Sulfosulfuron ND ND ND Atrazine + + + Tribenuron ND + ND Picloram ND ND ND 2,3,6-TBA + + ND 2,4,5-T ND + + Imazamethabenz A ND + ND Imazamethabenz B ND + ND Imazethapyr ND + + MCPB + ND ND Fenoprop + + + Benzoylprop ND ND ND Butylate + ND + Desethylatrazine + + + Desethylsimazine ND ND + Diclofop ND ND ND Simazine ND ND ND Triallate ND ND ND Trifluralin ND ND ND Chlorpyrifos + ND + Dimethoate ND ND ND Saskatchewan Alberta Herbicide 10 11 12 Mean total 128 271 125 concentration 2,4-D 28 [+ or -] 12 37 [+ or -]28 83 [+ or -] 109 MCPA 43 [+ or -]24 22 [+ or -]29 20 [+ or -]21 Clopyralid 35 [+ or -]14 3.6 [+ or -] 1.6 7.1 [+ or -]5.0 Diclorprop 1.4 [+ or -]1.1 + 3.9 [+ or -]3.1 Dicamba 1.8 [+ or -] 1.5 2.1 [+ or -]0.9 ND Mecoprop 11 [+ or -]4.9 5.1 [+ or -]5.2 1.3 [+ or -]0.8 Bromoxyni 2.0 [+ or -]2.5 2.1 [+ or -]2.2 + Ethametsulfuron 2.1 [+ or -]2.4 ND ND Sulfosulfuron ND ND ND Atrazine ND ND + Tribenuron + ND ND Picloram ND 167 [+ or -]114 ND 2,3,6-TBA + + ND 2,4,5-T + + ND Imazamethabenz A ND ND ND Imazamethabenz B ND ND ND Imazethapyr + ND ND MCPB + ND ND Fenoprop + + ND Benzoylprop + + ND Butylate ND ND ND Desethylatrazine + + + Desethylsimazine + + + Diclofop ND + + Simazine + ND + Triallate ND + Trifluralin ND ND ND Chlorpyrifos ND + ND Dimethoate ND ND ND Alberta Herbicide 13 14 15 Mean total 1062 48 98 concentration 2,4-D 597 [+ or -]199 17 [+ or -]6.3 12 [+ or -] 6.0 MCPA 178 [+ or -]52 16 [+ or -]6.3 15 [+ or -] 12 Clopyralid 58 [+ or -] 19 7.0 [+ or -] 2.5 29 [+ or -] 10 Diclorprop + + + Dicamba 1.1 [+ or -]0.9 2.9 [+ or -]0.7 + Mecoprop 2.4 [+ or -] 1.6 2.5 [+ or -] 1.1 5.7 [+ or -]3.8 Bromoxyni 0.8 [+ or -]0.5 + ND Ethametsulfuron ND ND ND Sulfosulfuron ND ND ND Atrazine ND ND ND Tribenuron ND ND ND Picloram 216 [+ or -]145 ND + 2,3,6-TBA + + ND 2,4,5-T 1.3 [+ or -] 1.3 + + Imazamethabenz A + ND + Imazamethabenz B + ND ND Imazethapyr + ND ND MCPB + + ND Fenoprop 0.9 [+ or -] 1.7 + ND Benzoylprop ND ND Butylate + ND ND Desethylatrazine + + + Desethylsimazine + + + Diclofop + ND + Simazine ND ND ND Triallate ND + ND Trifluralin ND ND ND Chlorpyrifos ND ND ND Dimethoate ND ND ND Abbreviations: +, detections in < 50% of samples; ND, not detected. Table 5. Mean herbicide concentrations in reservoirs, calculated herbicide reduction in water treatment facilities, herbicide concentrations in drinking water, and Canadian drinking water guideline values Reservoirs Water treatment plant Mean conc Mean Variability No. of (a) percent paired Herbicide (ng/L; n = reduction (range, %) samples 163) 2,4-D 123 39 0-84 28 MCPA 57 45 0-93 26 Clopyralid 28 14 0-88 27 Dichlorprop 16 29 0-55 19 Dicamba 6.6 38 0-95 19 Mecoprop 4.4 34 0-80 11 Bromoxynil 2.4 46 0-98 12 Picloram - 33 16-45 3 Imazethapyr - 38 0-79 3 Imazamethabenz A and B - 77 65-93 3 Atrazine - 44 0-71 5 Ethametsulfuron - 60 23-92 7 Tribenuron - 28 0-91 7 Thifensulfuron - - - 2 Sulfosulfuron - 86 100 1 Metsulfuron - - - 1 2,3,6-TBA - - - - Drinking water Calculated Calculated Maximum mean mean conc (d) in annual conc maximum drinking Guideline (b) conc (c) water in (e) Herbicide (ng/L; n = (ng/L; n = July (ng/L) 163) 111) (ng/L; n = 28) 2,4-D 75 364 589 100,000 MCPA 31 98 865 2,000 (f) Clopyralid 24 50 393 None Dichlorprop 11 + 105 100,000 (f) Dicamba 4 + 748 120,000 Mecoprop 3 1.6 42 10,000 (f) Bromoxynil 1 + 227 5,000 Picloram - 145 174 None Imazethapyr - ND 3 None Imazamethabenz A and B - + 101 None Atrazine - ND 7.4 5,000 Ethametsulfuron - ND 4 None Tribenuron - ND 4 None Thifensulfuron - ND < 2 None Sulfosulfuron - ND 2.9 None Metsulfuron - ND < 2 None 2,3,6-TBA - + 3.8 None Abbreviations: +, present at < 1 ng/L; -, insufficient data to calculate value for cell; conc, concentration; ND, not detected. (a) Calculated from data in Table 4. (b) Mean reservoir concentration adjusted for percent reduction. (c) Concentrations for reservoir 13 (Table 4) adjusted for percent reduction. (d) Maximum concentrations of individual herbicides in drinking water samples ( n= 28). (e) Data from CCME (1999). (f) Data from World Health Organization (2004).
The total number of herbicides detected during the study was similar for all three provinces (22 in Manitoba and Saskatchewan and 24 in Alberta). However, for herbicides other than the seven discussed above, some regional differences were evident (Table 4). Differences included a higher frequency of detection of atrazine and sulfonylurea herbicides in reservoirs in southern Manitoba, whereas picloram was detected only in reservoirs in Alberta.
For those herbicides consistently detected in July, we tested if concentrations were significantly greater in July samples than in early spring samples (April/May) with a one-way, paired two-sample t-test (p < 0.05, data were log-transformed to equalize e·qual·ize
v. e·qual·ized, e·qual·iz·ing, e·qual·iz·es
1. To make equal: equalized the responsibilities of the staff members.
2. To make uniform. variances). For six herbicides (bromoxynil, MCPA, 2,4-D, diclorprop, dicamba, and clopyralid), concentrations were significantly greater in July samples than in early spring (Table 6, Figure 3A, MCPA only). Most of these herbicides exhibited a 2-to 4-fold increase except for bromoxynil, which showed a 20-fold increase in concentration from April/May to July. For the other herbicides tested (mecoprop, tribenuron, ethametsulfuron, and imazamethabenz A and B), concentrations were higher in July samples but did not differ significantly from those in the April/May samples. Finally, because there was an extreme rain event in Manitoba in the summer of 2005, we performed the paired t-tests with and without the July 2005 samples; the significance of the analyses was unaffected by inclusion or exclusion of these samples in the analysis. Other herbicides, such as the sulfonylurea herbicides, generally had similar concentrations throughout the year (Figure 3B).
Effect of water treatment. Drinking water contained an average of 6.4 herbicides (n = 28 samples), with the number ranging from 3 to 15 depending on the location. We detected 21 herbicides in the 28 drinking water samples. The reservoir and drinking water samples collected simultaneously in early July indicated that water treatment at these communities reduced herbicide concentrations by an average of 14-86%, depending on the herbicide (Table 5). However, percent reduction (based on individual herbicides detected in both reservoir and drinking water samples) was highly variable from one treatment facility to another, and often between years at the same facility. Water treatment generally reduced bromoxynil, dichlorprop, dicamba, mecoprop, imazethabenz, and atrazine concentrations to nondetectable levels in the drinking water when reservoir concentrations were < 20 ng/L.
The highly variable reduction in herbicide concentrations (Table 5) showed no obvious relation to differences in treatment procedures. For example, for six water treatment facilities, reduction of 2,4-D concentrations differed by at least 30% between 2004 and 2005. However, our data showed little difference in 2,4-D reduction between the three largest facilities with the more sophisticated water treatment procedures and the three smallest facilities (mean 2,4-D reduction of 37% and 38%, respectively). In another treatment comparison, MCPA reduction was not significantly different among those facilities that used potassium permanganate (42.3%, n = 12) and those that did not [48.0%, n = 14; two sample t-test with arcsine (square root) transformation, p = 0.62]. However, the community with the most sophisticated treatment technology (membrane filtration) had the highest average removal rate for dichlorprop (47%), chlopyralid (59%), and MCPA (> 95%) (mean for two samples), but not for 2,4-D or dicamba.
Herbicides in drinking water. We calculated mean annual concentration of herbicides in drinking water from the average concentrations of herbicides in reservoirs (mean of means calculated from data in Table 4) times the mean percent of these same chemicals remaining after water treatment (Table 5). To calculate these estimates, we assumed that the average herbicide concentrations in reservoirs (determined for May, June, July, August, October, February, and April data) and mean percent reduction due to water treatment in July would be applicable annually. For the seven herbicides detected frequently across the northern Great Plains, mean annual concentrations in drinking water were 75 ng/L 2,4-D, 31 ng/L MCPA, 24 ng/L clopyralid, 11 ng/L dichlorprop, 4 ng/L dicamba, 3 ng/L mecoprop, and 1 ng/L bromoxynil. Our data show that, from time-to-time, residents in some communities were exposed to relatively high concentrations of a few of these chemicals in drinking water for short periods. For example, the mean annual concentration of 2,4-D could occasionally be as high as 364 ng/L at one of the 15 communities, and maximum concentrations of several pesticides in drinking water samples could be > 100 ng/L (Table 5).
In 2005, following unusually high rainfall, we detected record concentrations (for this study) in Manitoba reservoirs for 2,4-D (1,850 ng/L), clopyralid (1,050 ng/L), bromoxynil (384 ng/L), imazamethabenz A and B (288 ng/L), ethametsulfuron (80 ng/L), and tribenuron (30 ng/L). The region was subjected to total average rainfall of 133.3 mm in the 15 days before sample collection. Total herbicide concentrations detected in the four reservoirs were higher than corresponding total concentrations in 2004 by factors of 2.1 to 10.6 (Table 7). The maximum number (15) and maximum total concentration (2,423 ng/L) of herbicides in drinking water also occurred after the high rainfall and runoff in southern Manitoba (Table 7). In the four communities in 2005, total herbicide concentrations in the drinking water were higher than corresponding total concentrations in 2004 by factors of 1.1 to 8.3.
Water treatment. We detected 2 insecticides, 27 herbicides, and 2 degradation products in reservoirs used as sources for drinking water by 15 communities in the northern Great Plains (Table 3). The insecticides were detected infrequently and at concentrations < 20 ng/L. Up to 15 herbicides were detected in single reservoir water samples. All of the communities had a water treatment facility and, on average, these reduced herbicide concentrations in the drinking water by 14-86% of those in the reservoir water (Table 5), depending on the herbicide, its concentration in the reservoir water, and, most likely, other factors. After treatment, however, 3-15 herbicides remained in potable water supplies at a combined concentration of < 2,500 ng/L.
Our results indicate that herbicide reduction at water treatment facilities was highly variable from one site to another and often from year-to-year. Furthermore, the results suggest that there were no obvious differences in herbicide reduction for different water treatment procedures. However, the single facility with membrane filtration had the highest average percent reduction for three of the five herbicides detected in drinking water at that facility. However, our study design provided only general estimates of pesticide reduction at specific water treatment facilities. To achieve greater precision, a larger number of samples would be required to improve statistical confidence, water samples would have to be collected exactly at the water intake of each facility (rather than midreservoir at a 2-m depth), and the water from that point tracked to the point of entry to the water distribution system.
Pesticide mixtures. Drinking water guidelines have been established by Health Canada Health Canada (French: Santé Canada) is the department of the government of Canada with responsibility for national public health.
Health Canada's goal is to improve Canadian life by improving Canadian longevity, lifestyle and use of public healthcare. (CCME 1999) and other agencies for only seven of the herbicides commonly detected in drinking water. Individual herbicide concentrations in drinking water were usually one to three orders of magnitude lower than established guidelines. Even the total concentration of all herbicides in drinking water following excessive rainfall in Manitoba (Table 7) did not exceed the guideline for any individual herbicide (Table 5). These guidelines were set to protect humans from adverse health effects when continuously exposed over their lifetime to these herbicides in drinking water. However, drinking water guidelines have not been established for a much more complex issue--exposure to mixtures of pesticides. Monitoring programs throughout North America North America, third largest continent (1990 est. pop. 365,000,000), c.9,400,000 sq mi (24,346,000 sq km), the northern of the two continents of the Western Hemisphere. and Europe, together with the results of this study, have demonstrated the widespread presence of pesticide mixtures in surface waters. Thus, it is important to establish if the toxicity of a mixture of pesticides is different from the sum of the toxicities of the single compounds, or if two or more pesticides simultaneously present in drinking water have synergistic effects Synergistic effect
A violation of value-additivity in that the value of a combination is greater than the sum of the individual values. .
Table 6. Herbicide concentrations (ng/L) in April/May and July reservoir water samples, number of paired comparisons, and statistical p-values. April/May July No. of Pesticide (mean (mean paired p-Value [+ or -]SE) [+ or -]SE) samples Significantly greater in July Bromoxynil 1.5 29.6 36 < 0.001 [+ or -]0.3 [+ or -]12.5 MCPA 36.5 89.1 42 < 0.001 [+ or -]8.7 [+ or -]13.8 Diclorprop 9.1 16.7 40 < 0.001 [+ or -]2.9 [+ or -]3.1 Dicamba 11.3 42.9 39 < 0.001 [+ or -]4.9 [+ or -]26.0 2,4-D 78.9 147.2 42 < 0.001 [+ or -]20.2 [+ or -]43.9 Clopyralid 26.1 55.8 42 0.001 [+ or -]6.3 [+ or -]24.8 Not significant Mecoprop 6.1 8.4 42 0.08 [+ or -]1.3 [+ or -]2.3 Tribenuron 1.3 4.9 12 0.18 [+ or -]0.2 [+ or -]2.5 Ethametsulfuron 6.9 8.5 18 0.88 [+ or -]1.9 [+ or -]4.4 Imazamethabenz 6.4 22.2 15 0.98 A [+ or -]1.7 [+ or -]13.6
The toxicity of mixtures of pesticides in waters is now receiving greater attention in the literature. Cassee et al. (1998) provided a detailed discussion of toxicologic interactions between chemicals in mixtures, and Chevre et al. (2006) presented a method of defining a risk quotient quotient - The number obtained by dividing one number (the "numerator") by another (the "denominator"). If both numbers are rational then the result will also be rational. for mixtures of herbicides with similar modes of action. Toxicity of pesticide mixtures is also being assessed. Using enclosures in a prairie wetland, Forsyth et al. (1997) demonstrated a greater than additive (synergistic) effect when the submersed macrophytes Potamogeton pectinatus and Myriophyllum sibiricum were exposed to a mixture of 2,4-D and picloram. Porter et al. (1999) measured aggressive behavior, thyroxine hormone levels, and ability to make antibodies against a foreign protein in mice treated with atrazine, aldicarb aldicarb /al·di·carb/ (al´di-kahrb) a carbamate pesticide used as an insecticide; in some countries, also used as a rodenticide.
a carbamate pesticide. , and nitrate (and their mixtures) at maximum concentrations typically detected in groundwater. Their results suggested that some mixtures, especially nitrate plus either pesticide, had effects not detected from exposure to the individual chemicals. Thus, when assessing environmental exposure involving mixtures of pesticides, single chemical evaluations of toxicity (e.g., Gandhi et al. 2000; Muir et al. 1991), although they provide useful information, generally have little practical value when assessing normal environmental exposure involving mixtures of pesticides.
In the context of mixtures, it is noteworthy that the 17 herbicides detected in the drinking water samples in the present study represent seven very different chemical classes: phenoxyalkanoic acids (2,4-D, mecoprop, MCPA, dichlorprop), sulfonylureas (ethametsulfuron, tribenuron, sulfosulfuron), pyridinecarboxylic acids (clopyralid, picloram), triazines triazines
selective herbicides including atrazine, propazine, simazine, prometone, prometryne. They are poisonous if given in sufficient quantity but the syndrome, weight loss, anorexia and weakness, is too nonspecific to be valuable diagnostically. (atrazine), hydroxybenzonitriles (bromoxynil), benzoic acids benzoic acid (bĕnzō`ĭk), C6H5CO2H, crystalline solid organic acid that melts at 122°C; and boils at 249°C;. It is the simplest aromatic carboxylic acid (see aryl group and carboxyl group). (dicamba, 2,3,6-TBA), and imidazolinones (imazamethabenz, imazethapyr). Thus, when mixtures of pesticides in drinking water include different chemical classes and, potentially, different modes of action, unexpected toxic effects may result.
The herbicides 2,4-D, MCPA, clopyralid, dichlorprop, dicamba, mecoprop, and bromoxynil are widely distributed Adj. 1. widely distributed - growing or occurring in many parts of the world; "a cosmopolitan herb"; "cosmopolitan in distribution"
bionomics, environmental science, ecology - the branch of biology concerned with the relations between organisms in drinking water reservoirs in the northern plains. This consistent pattern suggests that these chemicals should be evaluated as a single "toxic substance" when assessed from the perspectives of human health and environmental effects. Based on the present study, the approximate ratio of these individual chemicals (relative to bromoxynil) in this toxic substance in reservoir water would be as follows: 2,4-D, 51; MCPA, 24; clopyralid, 12; dichlorprop, 7; dicamba, 3; mecoprop, 2; and bromoxynil, 1 (calculated from data in Table 5). Depending on the percent reduction achieved by water treatment facilities for the various herbicides, the relative ratios of chemicals in this toxic substance could change for drinking water. In the present study, the ratios in the drinking water were as follows: 2,4-D, 75; MCPA, 31; clopyralid, 24; dichlorprop, 11; dicamba, 4; mecoprop, 3; and bromoxynil, 1 (Table 5). The increase in the ratios in drinking water occurred because bromoxynil underwent the greatest reduction during water treatment. Because all of these herbicides have been used in the prairie region for at least the previous two decades (Pesticide Manual 2006), this current pattern may approximate that of past years.
Source of pesticides to the reservoirs. Spring snowmelt runoff and atmospheric deposition are two potential transport routes for pesticides from fields to reservoirs. In 2003, after weeks of insignificant rainfall typical of the prairie region, some herbicides reached peak concentrations in the reservoirs in early July rather than after spring snowmelt runoff (Figure 3A). This pattern suggests that the atmospheric pathway, most likely involving both long-range transport and application drift (short-range transport; Grover et al. 1997), was dominant for these herbicides. Atmospheric transport appeared to be an important pathway to reservoirs for bromoxynil, MCPA, diclorprop, dicamba, 2,4-D, and clopyralid because these herbicides typically reached peak concentrations in early July in the absence of runoff. Long-range transport would include deposition of pesticides to the reservoirs in rain, on soil particles, and from direct transfer of pesticide from the atmosphere to the reservoir at the air-water interface. Relatively high concentrations of pesticides have been detected in the atmosphere (Grover et al. 1976; Rawn et al. 1999a; Waite et al. 2002), in rain (Hill et al. 2002; Rawn et al. 1999b; Strachan 1988), and on wind-eroded soil particles in the northern plains (Larney et al. 1999). In this region, mass balance calculations indicate that atmospheric deposition alone can account for the levels of herbicides detected in shallow aquatic habitats in the northern plains (Donald et al. 2001). Moreover, the relatively homogenous homogenous - homogeneous distribution of several herbicides evident in the reservoirs (Figure 2) is best explained by atmospheric transport and deposition to surface waters throughout the northern plains landscape.
Although atmospheric processes were most likely the principal mechanisms for movement of herbicides from fields to reservoirs, snowmelt and occasionally rainfall runoff probably contributed to the total loading of pesticides into the reservoirs (Muir and Grift grift Slang
1. Money made dishonestly, as in a swindle.
2. A swindle or confidence game.
v. grift·ed, grift·ing, grifts
v.intr. 1987; Nicholaichuk and Grover 1983; Rawn et al. 1999c; Waite et al. 1992). Snowmelt runoff was probably an important source of herbicides, such as ethametsulfuron and imazamethabenz, to the reservoirs. After herbicide application to crops, major rainfall runoff from agricultural landscapes (Hunter et al. 2002) can transport relatively high concentrations of a variety of insecticides and herbicides to reservoirs and wetlands (Table 7) (Donald et al. 1999, 2005; Wauchope 1978). During the present study, the highest recorded concentrations of six herbicides in reservoir water followed 133 mm of rain in 15 days.
Management practices could be implemented to reduce concentrations of pesticides in small prairie reservoirs. This would require the cooperation of the landowners who farm the catchments surrounding reservoirs and could include organic farming organic farming, the practice of raising plants—especially fruits and vegetables, but ornamentals as well—without the use of synthetic pesticides, herbicides, or fertilizers. , establishment of buffer strips of natural vegetation along field margins, and development of wildlife habitat along reservoir margins. Practices to reduce deposition of application drift to reservoirs might include decreased aerial application Aerial application, commonly called crop dusting, involves spraying crops with fertilizers, pesticides, and fungicides from an agricultural aircraft. The specific spreading of fertiliser is also known as aerial topdressing. of pesticides near drinking water reservoirs, spraying when wind speeds are optimal, and use of precision applicators. Also, concentrations in runoff to reservoirs could be reduced through use of pesticides with lower water solubility Water is a bent, polar compound and possesses the ability to Hydrogen bond. As a result, it has unique solubility characteristics as a solvent and functions differently at different temperatures. Polarity
Water Solubility, US Geological Survey . However, none of the above procedures would completely eliminate pesticides from drinking water reservoirs because long-range atmospheric transport and deposition from beyond reservoir catchments maintain detectable levels of a variety of herbicides in all surface waters in the northern plains.
Table 7. Comparison of the total herbicide concentration (ng/L) in reservoir water and in drinking water from four reservoirs in Manitoba on 5 or 6 July after a dry (2004) or wet (2005) period. 2004 (a) 2005 (a) Community Total Drinking water Total Drinking water reservoir concentration reservoir concentration concentration (no. of concentration (no. of herbicides) herbicides) 1 825 444 (8) 1,746 2,423 (b)(15) 2 347 177 (7) 1,733 578 (7) 3 213 184 (7) 2,269 1,532 (10) 4 395 145 (8) 876 161 (9) Mean (7.5) (10.3) Precipitation was measured by meteorologic stations 15 days before sample collection: 22.3 mm for 2004 and 133.3 mm for 2005. (a) Number of drinking water samples = 4. (b) Drinking water concentration > reservoir water concentration.
We detected a variety of pesticides at nanogram-per-liter levels in reservoirs that supply drinking water to small communities situated in the northern Great Plains. Water treatment in these communities reduced pesticide concentrations, but depending on the location, 3-15 herbicides remained in drinking water. Total concentrations of all pesticides generally were well below guidelines for individual pesticides; however, guidelines have been established for only 7 of the herbicides commonly detected in reservoir water, and no guidelines have been established for pesticide mixtures. Management practices could be implemented within drainage areas to lower the pesticide levels in small reservoirs and thereby improve the aesthetic quality and the safety of the water.
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n. pl. com·pen·di·ums or com·pen·di·a
1. A short, complete summary; an abstract.
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A salt or ester of carbamic acid. ), atrazine (triazine tri·a·zine
1. Any of three isomeric compounds, C3H3N3, each having three carbon and three nitrogen atoms in a six-membered ring.
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Rawn DFK DFK Direct Free Kick (Soccer)
DFK Deep French Kiss
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Address correspondence to D.B. Donald, Environment Canada, Room 300 Park Plaza, 2365 Albert St., Regina, Saskatchewan, Canada, S4P S4P Solutions for Partners (Germany) 4K1. Telephone: (306) 780-6723. Fax: (306) 780-5311. E-mail: firstname.lastname@example.org
*Current address: Environment Canada, National Hydrology Research Centre, Saskatoon, Saskatchewan, Canada.
We thank the communities and their representatives who agreed to participate in this study. We appreciate the superb efforts of L. Mottle mot·tle
tr.v. mot·tled, mot·tling, mot·tles
To mark with spots or blotches of different shades or colors.
1. A spot or blotch of color.
2. A variegated pattern, as on marble. , R. Crosley, J. Syrgiannis, W. Aitken, D. Legault, and B. Holliday, who collected water from reservoirs and municipal facilities over a large geographic area, and J. Bailey for analysis of the water samples for sulfonylurea herbicides.
This project was supported by the Pesticide Science Fund of Environment Canada.
The authors declare they have no competing financial interests.
Received 19 June 2006; accepted 15 May 2007.
David B. Donald, (1) Allan J. Cessna,(2),* Ed Sverko, (3) and Nancy E. Glozier (4)
(1) Environment Canada, Regina, Saskatchewan, Canada; (2)Agriculture and Agri-Food Canada The Department of Agriculture and Agri-Food, also referred to as Agriculture and Agri-Food Canada (AAFC) (French: Agriculture et Agroalimentaire Canada), is the department of the government of Canada with responsibility for policies governing agriculture , Saskatoon, Saskatchewan, Canada; (3)National Laboratory for Environmental Testing, Environment Canada, Burlington, Ontario, Canada; 4National Hydrology Research Centre, Environment Canada, Saskatoon, Saskatchewan, Canada