Occurrence of pesticides

The documented occurrence of pesticides in surface water is indicative that mnoff is an important pathway for transport of pesticide away from the site of appHcation. An estimated 160 t of atra2ine, 71 t of sima2ine, 56 t of metolachlor, and 18 t of alachlor enter the Gulf of Mexico from the Mississippi River annually as the result of mnoff (47). Field appHcation of pesticides inevitably leads to pesticide contamination of surface mnoff water unless mnoff does not occur while pesticide residues remain on the surface of the soil. The amount of pesticides transported in a field in mnoff varies from site to site. It is controUed by the timing of mnoff events, pesticide formulation, physical—chemical properties of the pesticide, and properties of the soil surface (48). Under worst-case conditions, 10% or more of the appHed pesticide can leave the edge of the field where it was appHed. 

Kolpin DW, Barbash JE, Gilliom RJ. 1998. Occurrence of pesticides in shallow groundwater of the United States Initial results from the National Water-Quality Assessment Program. Environ Sci Technol 32 558-566. 

Neidert E, Saschenbrecher PW. 1996. Occurrence of pesticide residues in selected agricultural food commodities available in Canada. J Assoc Off Anal Chem 79 549. 

Planas C, Caixach J, Santos FJ, et al. 1997. Occurrence of pesticides in Spanish surface waters. Analysis by high resolution gas chromatography coupled to mass spectrometry. Chemosphere 34(ll) 2393-2406. 

Maguire RJ, Tkacz RJ. 1993. Occurrence of pesticides in the Yamaska River, Quebec. Arch Environ Contam Toxicol 25(2) 220-226. 

Donald, D.B. and J. Syrgiannis (1995). Occurrence of pesticides in prairie lakes in Saskatchewan in relation to drought and salinity. J. Environ. Qual., 24 266-270. 

Skark, C. and N. Zullei-Seibert (1995). The occurrence of pesticides in groundwater - results of case-studies. Int. J. Environ. Anal. Chem., 58 387-396. 

Turning now to the occurrence of pesticides, it can be said again with no fear of contradiction that pesticides are present in all types of environment in all parts of the world. The levels may be too low to detect by methods now at our disposal and may have no immediate significance in many areas, particularly those remote from civilization. It is not the purpose of this paper, however, to evaluate the significance of the amounts present but rather to discuss the occurrence, regardless of amount. 

In order to adapt the system to on-line monitoring, in wastewater control, for example, the occurrence of pesticide in a flow buffer was investigated. It was found possible to differentiate between reversible and irreversible inhibition and to quantify a reversible inhibitor. Since it was possible with the calorimetric method to use the natural substrate acetylcholine to assay cholinesterase, instead of the commoly used thiocholines, this methodology might be useful in medical research as well. 

Abstract Indoor contamination is one source of exposure to toxic pollutants and has been classified as a high environmental risk. Epidemiological research linked health effects including childhood leukemia and neuroblastoma to the indoor occurrence of pesticides. Pesticides in indoor environments contribute to human exposure via inhalation, non dietary ingestion and dermal contact. Sources for pesticides indoors are direct applications, pesticides used in varnishes, colors, adhesives, etc., or in finishing textiles, leather, carpets, etc., and pesticides brought in from outdoors. Results for pesticides in indoor environments from different countries and obtained under different conditions are compiled in this chapter. They are discussed by applying two approaches (1) the comparison with reference values... 

Reference values for pesticides in indoor air are not available. Studies obtained under specific criteria for the selection of these samples are given in Table 2. Some of them may give an impression of the ubiquitous occurrence of pesticides in indoor air. 

The objective of large-scale retrospective ground-water studies is co characterize the extent of occurrence of pesticides in wells over a large area. These statistical surveys cover multicounty... 

These reports all focus on nonpoint sources of pesticides leaching to ground water. However, the extent of occurrence of pesticides in ground water from agricultural and industrial point sources is also not known. A separate investigation into this topic would be warranted. 

Widespread occurrence of pesticide chemicals in groundwater and surface water supplies has prompted an increased research effort to develop improved methods for estimating pesticide mobility. 

Bratanova Z., Kovacicova I, Gopina G., (1998), A Review of Existing Data on the Occurrence of Pesticides in Water of the River Danube and Its Tributaries, Fresenius Env. Bull. 7,495-501. 

Spliid, N.H. and Koppen, B., Occurrence of pesticides in Danish shallow groundwater, Chemo-sphere, 37,1307,1998. 

The occurrence of pesticides in the atmosphere or in water supplies is an important national issue (1-3), Numerous monitoring studies have demonstrated that agricultural use of pesticides can contribute to both atmospheric and water... 

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