PRACTICAL STUFF!

Airborne and Bacteria - Background Levels in Office Buildings

* The number of buildings that may be labeled as "sick buildings" seems to have increased in the last two decades.

* A major contribution to this increase may be reduced provision of outside air in the interest of energy savings.

* A variety of volatile organic compounds (VOCs), fungal spores, bacteria, protozoa, pollens, and dust mites have been implicated as agents in health complaints related to indoor air quality (IAQ).

* Symptoms associated with poor IAQ include irritation, headaches, fatigue, sinus congestion, allergic reactions, and asthma.

* These symptoms are common and may be caused by factors other than poor IAQ.

* In terms of prevention, a consensus is developing in the scientific community that

- fungal growth should not occur to any significant degree in a properly designed and functioning building,

- large amounts of visible fungal growth pose a potential health risk in the indoor environment and should be removed, and

- stagnant water poses a potential health risk in the indoor environment.

* Even toxic fungi, however, are a normal part of outdoor and indoor environments.

* Measures of"acceptable" levels of indoor fungi and bacteria are needed.

* Few data have been published on normal background levels of airborne fungi and bacteria in office spaces.

* At California State University, recovery from a major earthquake presented an opportunity to study a variety of temporary office structures and to compare bioaerosols and their degree of temporal and spatial variability.

* The geometric means for airborne fungi were low and ranged from 42 to 110 colony-forming units per cubic meter (CFU/[m.sup.3]).

* Geometric means for airborne bacteria were in a similar range of 44 to 150 CFU/[m.sup.3].

* Concentrations in different locations within structures generally did not differ significantly.

* Likewise, seasonal variation of bacteria and fungi concentrations was quite low.

Dairy Feedlot Contributions to Groundwater Contamination: A Preliminary Study in New Mexico

* Feedlot milk production has increased dramatically in New Mexico in the past decade, along with the potential for groundwater contamination from animal wastes.

* Manure and wastewater from animal feeding operations have the potential to add the following contaminants to the environment:

- nutrients (e.g., nitrogen, phosphorus),

- sediment,

- pathogens,

- heavy metals,

- hormones,

- antibiotics, and

- ammonia.

* Excess nutrients in water can result in or contribute to eutrophication and anoxia (i.e., low levels of dissolved oxygen).

* Excess nutrients also have been associated with outbreaks of microbes such as Pfiesteria piscicida.

* This preliminary study analyzed six years of groundwater quality data from seven dairy feedlots and found elevated levels of

- nitrate,

- ammonia,

- chloride,

- total Kjeldahl nitrogen (TKN), and

- total dissolved solids (TDS).

* Wastewater from the dairy feedlots is typically collected in lagoons until conditions are suitable for land application or until the liquid evaporates.

* Mean nitrate levels were significantly the highest near clay-lined lagoons. Mean TKN, chloride, and TDS levels were slightly higher for clay linings than for cement and synthetic linings.

* Mean ammonia levels were significantly the lowest for synthetic linings. Nitrate and TDS levels were slightly lower for synthetic linings than for cement and clay lagoon liners.

* These results suggest that synthetic linings are most effective and clay linings least effective.

* Nitrate, ammonia, chloride, and TDS levels varied significantly by feedlot size.

* Nitrate was the only groundwater contaminant measured that showed a consistently increasing trend from 1992 to 1997.

This department, "Practical Staff!" originated from you, our readers, via your responses on "Tell Us What You Think" forms. Many of you have expressed to us that one of the main reasons you read the Journal of Environmental Health is to glean practical and useful information for your everyday work-related activities. In response to your feedback, we dedicate this section to you with salient points to remember about the features in each issue.