Pesticide Analysis: An Overview of Methods.
In the U.S. alone, approximately 4.5 billion pounds of chemicals are used as pesticides per year. That figure includes 20,700 pesticide products and about 890 active ingredients registered as pesticides. Agricultural use accounts for more than three-fourths of the volume of pesticides used, with the remainder used for industrial and home or garden applications. Herbicides are the most widely used type of pesticide: The herbicide atrazine is the pesticide most commonly used in U.S. agricultural crop production, and the herbicide 2,4-D is the pesticide most commonly used for home/garden and industrial applications.
Because of their toxicity and widespread usage, pesticides present a risk to human health and the environment. As a result, pesticide analyses are an important part of environmental monitoring and testing. The three sections below describe the most common methods of analysis and provide tables detailing some of the pesticides covered by those methods.
Method 8081A/608--Organochlorine Pesticides
Methods 8081A and 608 determine the concentrations of various organochlorine pesticides in extracts from solid and liquid matrices, using fused-silica, open-tubular, capillary columns with electron capture detectors (ECDs). Table 1 identifies some (but not all) of the pesticides analyzed by this method. Many of the organochlorine pesticides listed in Table 1 have been discontinued in the United States, but most will persist in soil for many years.
Method 8151A--Organochlorine Herbicides
Method 8151A is a capillary gas chromatographic (GC) method for determining the presence of certain chlorinated acid herbicides and related compounds in aqueous, soil, and waste matrices. Table 2 gives some (not all) of the compounds analyzed by this method.
Method 8141--Organophosphate Pesticides
Method 8141 is a capillary gas chromatographic (GC) method that uses nitrogen-phosphorous or flame photometric detectors to determine the presence of certain organophosphate pesticides and related compounds in aqueous, soil, and waste matrices. Table 3 gives some (not all) of the compounds analyzed by this method.
(Source: This material appeared in Precision Analytical Laboratories' Environmental Tech Tip Program, a free program distributed by Precision Analytical Laboratories, Inc. To subscribe, go to [less than]http://www.palabs.com[greater than] or send a message to [less than]email@example.com[greater than] with "Add Environmental Tech Tips" in the subject line.)
Method 8081A/608 Pesticide Properties and Uses 4,4 -DDD Miticide formerly use on vegetables and tobacco. Discontinued in U.S. since 1970s. 4,4 -DDE Degradation product of DDT. Insecticide, no longer used in U.S. 4,4 -DDT Insecticide extensively used from 1944 until severely restricted in 1973 because of adverse effects on wildlife. Aldrin Insecticide introduced in 1959, primarily for soil insects including termites. Discontinued in U.S. Degrades to dieldrin. Alpha-BHC Insecticide introduced in 1942, no longer used in U.S. Beta-BHC Insecticide introduced in 1942, no longer used in U.S. Chlordane Insecticide used since 1945 for termite control & wood treatment. Technical product includes 2 isomers & heptachlor. Delta-BHC Insecticide introduced in 1942, no longer used in U.S. Dieldrin Insecticide introduced in 1949, formerly used on corn and for termite control. Restricted in the U.S. after 1974. Endosulfan I Insecticide introduced in 1956, used on citrus, fruits, cotton, vegetables. Exists as two isomers, I and II. Endosulfan II Insecticide introduced in 1956, used on citrus, fruits, fiber crops, vegetables. Exists as two isomers, I and II. Endosulfan sulfate Oxidation product of endosulfan. Found in the environment as a result of endosulfan use. Endrin Insecticide introduced 1951 and discontinued 1987. Formerly used on cotton, grains. Endrin aldehyde Oxidation product of endrin. Gamma-BHC (lindane) Insecticide introduced in 1942, no longer used in U.S. More toxic than DDT. Formerly used on wheat, corn, & pastures. Heptachlor Insecticide introduced in 1951, now restricted. Used for termite control & wood treatment. Heptachlor epoxide Oxidation product of heptachlor, occurs in soil after treatment with heptachlor. Methoxychlor Insecticide introduced in 1944. Used on fruit trees, vegetables, cattle, home gardens. Toxaphene Insecticide and miticide introduced 1948. Used on cotton, vegetables, livestock, poultry, soybeans, alfalfa, wheat. Method 8151A Herbicide Properties and Uses 2,4,5-T Herbicide used after 1944 in industry, range lands, & lawns. U.S. has cancelled use since 1985. 2,4,5-TP Herbicide introduced in 1953 for industrial uses, (Silvex) on pastures & range land, and along floodways & canals, U.S. cancelled use in 1985. 2,4-D The herbicide most commonly used for nonagricultural applications, eighth most common herbicide for agricultural use. 2,4-DB Herbicide introduced in 1957. Dicamba Selective postemergent herbicide for use on corn & wheat, and on landscapes & grains. Dinoseb An herbicide & insecticide introduced in 1945, now discontinued in U.S. Used on soybean, vegatables, fruits, & citrus. Method 8141 Pesticide Properties and Uses Chlorpyrifos (Dursban & One of the most widely used organophosphates, Lorsban) found in many home & garden products for controlling insects. Residential uses include treatment of lawns, ornamentals, & interiors of homes & buildings. Also used as a termiticide & in pet collars. Widely used on more than 40 different agricultural crops/sites. Because of health risks to children, U.S. EPA recently banned chlorpyrifos from use in gardens & homes, and curtailed its use in agricultural applications. Demeton (Systox) Systemic insecticide-acaricide, introduced in 1954 and discontinued in 1989. Diazinon Insecticide, acaricide, nematicide used widley since 1952 on fruits, vegetables, field crops, range, grasslands & household insects. Disulfoton Systemic insecticide-acaricide introducted in 1956. Ethion Insecticide-acaricide introduced in 1955 for control of aphids, mites, & leafhoppers on crops & ornamentals. Slowly oxidized in air. Malathion Insecticide, algaecide, miticide introduced in 1950. Used on fruits, vegatables, & ornamentals. Methyl parathion Insecticide used on crops. Introduced in 1949, more rapidly hydrolyzed than parathion. Parathion Insecticide, miticide, avicide developed in 1944. Very toxic to mammals as well as insects. Metabolized to p-nitrophenol.
|Printer friendly Cite/link Email Feedback|
|Publication:||Journal of Environmental Health|
|Date:||Mar 1, 2001|
|Previous Article:||Michael G. Halko.|
|Next Article:||Dear Employee: Please Go, Please Stay.|