Pesticides water contamination

Insecticide methomyl is a very toxic pesticide and is highly soluble in water (57.9 g/1). It has a low sorption affinity to soil and can cause groundwater and surface water contamination in agricultural areas. Solubilities of methomyl in different solvents are in methanol 1000 g/1, in aceton 730 g/1, in ethanol 420 g/1, in isopropanol 220 g/1, in toluene 30 g/1. 

Despite the use of 2.5 million tons of pesticide worldwide, approximately 35% of potential crop production is lost to pests. An additional 20% is lost to pests that attack the food post-harvest. Thus, nearly one-half of all potential world food supply is lost to pests despite human efforts to prevent this loss. Pesticides, in addition to saving about 10% of world food supply, cause serious environmental and public health problems. These problems include human pesticide poisonings fish and bird kills destruction of beneficial natural enemies pesticide resistance contamination of food and water with pesticide residues and inadvertent destruction of some crops. 

Clark CS, Meyer CR, Gartside PS, et al. 1982. An environmental health survey of drinking water contamination by leachate from a pesticide waste dump in Hardeman County, Tennessee. Arch Environ Health 37 9-18. 

There may be other pesticide contaminants and ground water contamination sites yet to be discovered. Therefore, the 12 different pesticides found In a total of 18 different states, as listed In Table III, represents the minimum number of pesticides and their distribution. There have been several reports of plcloram In well water, most of them anecdotal. However, It cannot be substantiated that the contamination has been due to normal pesticide use and leaching throu the soil or due to spillage. 

Nitrates - high levels In the ground water are Indicative of pesticide ground water contamination potential. 

Finally, a few miscellaneous compounds which were identified in the Delaware River and which have not been previously reported as water contaminants will be discussed Chloro (trifluoromethyl) aniline and chloro (trifluoromethyl) nitrobenzene (no. 55 and 56) were identified in the water, they had maximum concentrations at river mile 78. Both compounds represent common sub-structures in various pesticide and dye molecules, and several of the companies located along the river have patents using these compounds (30-32j. It is possible that these compounds are actually present in the river water as such, but it is also possible that they are formed in the GC injection port by pyrolytic degradation of larger pesticide or dye molecules (see above). All three binaphthyl-sulfone isomers (no. 92) were identified in the river water near Philadelphia. Product literature for one of the companies in the area indicates production of condensed sulfonated polymers derived from naphthalene sulfonic acid and maleic anhydride. It seems likely that the binaphthylsulfones are formed as by-products during preparation of this commercial product. 

Chapter 5 of the document reviews the UFs used by UK Government departments, agencies, and their advisory committees in human health risk assessment. Default values for UFs are provided in Table 3 in the UK document with the factors separated into four classes (1) animal-to-human factor, (2) human variability factor, (3) quality or quantity of data factor, and (4) severity of effect factor. The following chemical sectors are addressed food additives and contaminants, pesticides and biocides, air pollutants, drinking water contaminants, soil contaminants, consumer products and cosmetics, veterinary products, human medicines, medical devices, and industrial chemicals. 

Lindane Pesticide - organochlorine - bioaccumulates - insecticide widely used prior to 1983 Regulated as drinking water contaminant by US EPA... 

Pesticide registrants must also submit environmental fate and effects data to the EPA as part of an application for pesticide registration. The EPA uses such environmental data to characterize the persistence and partitioning of a pesticide in the environment and the pesticide s environmental metabolites and degradates. This information is used by the EPA to assess the potential for human exposure via drinking water contamination and environmental exposure of organisms such as fish, wildlife, and plants to the pesticide or its metabolites. 

Most of the common pesticides used now and in the past have also been found in the atmosphere, including DDT, toxaphene, dieldrin, heptachlor, organophosphorous insecticides, triazine herbicides, alachlor and metolachlor. These airborne pesticides return to the earth with rainfall to further contribute to water contamination. A recent... 

The impact of pesticides on water quality in organic systems has rarely been studied (Stock-dale et al. 2001). Again, however, most of the water contamination comes from herbicides used in conventional farming. There is some debate about the disposal of sheep dip and the relative risks of pyrethroids versus organophosphates. Organic farmers only use the former and they are potentially more damaging to aquatic habitats. 

Suffet coedited with M. J. McGuire ADVANCES IN CHEMISTRY SERIES No. 202, Treatment of Water by Granular Activated Carbon, as well as a two-volume set, Activated Carbon Adsorption of Organics from the Aqueous Phase. He also edited a two-volume treatise, The Fate of Pollutants in the Air and Water Environments he was a journal editor for a special issue of the Journal of Environmental Science and Health, Part A—Environmental Science and Engineering and he served on the editorial board of the companion journal, Journal of Environ-mental Science and Health, Part B—Pesticides, Food Contaminants, and Agricultural Wastes. He serves on the editorial boards of the journals Chemosphere and CHEMTECH. He is now completing a 4-year term as treasurer of the ACS Division of Environmental Chemistry. 

Until very recently the risks associated with different types of chemicals such as food additives, pesticides, environmental contaminants and natural constituents of food were assessed and managed separately. However, a particular substance might fall into two or more of these categories and so the opportunity for simultaneous exposure might be overlooked. Furthermore, exposure to a chemical could occur through diet, drinking water, air pollution or dermal absorption. Aggregate exposure assessment aims to take all of the possible sources and routes of exposure into account in a realistic manner and thereby obtain a better overall estimate of risk. Initiatives have been set up in both the... 

Pesticides and polynuclear aromatics (PNAs) are the most commonly analyzed environmental contaminants. Analysis of PCBs, dioxans, and nitroor-ganics (explosives) is of growing importance. The major obstacles to adoption of environmental HPLC application are 1) awareness of the need, (i.e., environmental and drinking water contamination) and 2) the slow rate of development and acceptance of new AOAC and EPA-mandated HPLC and LC/MS methods. 

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