Herbicide, food chain contaminate

There is a vast range of aqueous organic pollutants with a wide toxicity profile. Some, e.g. polychlorinated biphenyls, certain herbicides, fungicides and pesticides, and organo-mercury compounds, are persistent and may bioaccumulate in the food chain. Trace contaminants such as sodium chloride, iron and phenols (especially if chlorinated) may also impart a taste to water. Typical consent levels for industrial discharges are provided in Table 13.10. 

Butoxyethanol was detected at a concentration of 23 g/L in a surface water sample collected in 1979 at a site in Kentucky where it has been estimated that as many as 100,000 drums of industrial waste were disposed of between 1967 and 1977 (Stonebreaker and Smith 1980). Examination of mass spectral libraries of data from water and soil samples from U.S. hazardous wasted sites taken between late 1987 and mid-1989 identified 2-butoxyethanol in 110 samples (Eckel et al. 1996). The media in which the compound was found was not indicated. No other data were found in the available literature on the levels of 2-butoxyethanol or 2-butoxyethanol acetate in surface or groundwater, or in soil or sediment such data would be useful to assess the potential for exposure from these media. The low estimated BCF and values of 2-butoxyethanol and 2-butoxyethanol acetate (see Section 5.3.1 and Tables 3-3 and 3-4), and the ease with which these compounds are metabolized in higher trophic level animals (see Section 2.3) indicate that these compounds will not biomagnify in the food chain and, consequently, that concentrations in food will be insignificant however, there may be some potential for food contamination from packaging and washing procedures (see Section 5.4.4). The minor use of 2-butoxyethanol in herbicides (see Section 4.3) may also present the potential for food contamination by this compound. 

A number of pesticides are used in vast amounts in agriculture and horticulture each year. As a result, waters, soils, and plants are frequently contaminated with these substances, which therefore constitute one of the major sources of potential environmental hazards to man and animals through their presence and concentration in the food chain. Pesticides are classified according to their chemical structure into organochlorines, organophosphates, carbamates, triazine herbicides,... 

In addition to these primary sources, the contamination of the food chain may create various waste products, such as industrial compost, landfill materials, sewage sludges, contaminated industrial products, for example herbicides based on 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), technical PCB mixtures, biocide pentachlorophenol (PCP) and its salts. 

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