Persistence in aquatic environment

S. Baneijee et al, Environmental Degradation of 1,1-Dimethyl-Hydrazine , CEEDO-78-14 (Paper No 11), 113-28 (1978) CA 90, 115966 (1978) [The objective of the author s program was to find the rate of degradation of UDMH in natural lake water so as to predict its persistence in aquatic environments. The information derived from the study includes the rate of oxidation of UDMH with Cu++ concn, and the fact that the combination of the pH of the lake water plus dissolved oxygen causes the degradation of UDMH—HC1 in the absence of microbes to form an unidentified product with absorption... 

Similar rate enhancements are expected for aliphatic hydrocarbons containing nitrogen and sulfur hetero-atoms bonded directly to the halogen-bearing carbon. It is readily apparent that chemicals containing structural features that allow for the delocalization of carbonium ion intermediates will not be persistent in aquatic environments. 

Sites near industrial areas in the Ebro have been found to have the highest concentration of priority contaminants [15, 47—49], while dispersion of agricultural products by drift, runoff and drainage has resulted in residues being found in ground-waters, rivers, coastal waters and lakes far from point sources [50]. Priority contaminants in aquatic environments include persistent organic pollutants (POPs) such as dichlorodiphenylethylenes (DDT) and polybrominated diphenyl ethers (PBDEs). 

Synthetic pyrethroids now account for at least 30% of the world insecticide market and are rapidly replacing other agricultural chemicals for control of insect pests. Fenvalerate is one of the more widely used synthetic pyrethroid insecticides. It is derived from a combination of a-cyano-3-phenoxybenzyl alcohol and a-isopropyl phenylacetate ester. Technical fenvalerate is a mixture of four optical isomers, each occurring in equal amounts but with different efficacies against insect pests. Fenvalerate does not usually persist in the environment for >10 weeks, and it does not accumulate readily in the biosphere. Time for 50% loss (Tb 1/2) in fenvalerate-exposed amphibians, birds, and mammals was 6 to 14 h for reptiles, terrestrial insects, aquatic snails, and fish it was >14 h to <2 days and for various species of crop plants, it was 2 to 28 days. Fenvalerate degradation in water is due primarily to photoactivity, and in soils to microbial activity. Half-time persistence in nonbiological materials is variable, but may range up to 6 days in freshwater, 34 days in seawater, 6 weeks in estuarine sediments, and 9 weeks in soils. 

Allan, R. J. (1994). Transport and Fate of Persistent Toxic Organic Chemicals in Aquatic Ecosystems the Niagara River to St. Lawrence River Estuary Example. In Hydrological, Chemical a. Biological Processes of Transformation a. Transport of Contaminants in Aquatic Environments, Proc. of the Rostov-on-Don symposium. May 1993, IAHS Publication, 219, pp. 21-32. 

Bisphenol A Production of resins (polycarbonate and epoxy resins). Component in flame retardant production Antioxidant, preservative - River water mean values 0.016 pg L 1 (Europe) and 0.5 pg L"1 (US) [66]. -SW <0.001-1 pg U1 [9] - WW effluents mean values 1.5 pg L-1 [67] Not persistent in surface water. Rapidly biodegraded in aquatic environments [68] and removed in WWTP. Half-life 1-4 days [69] in water. Accumulated in anoxic sediments [9]... 

Sikka, H.C. and Rice, C.P. Persistence of endothall in aquatic environment as determined by gas-liquid chromatography, J. Agrlc. FoodChem., 21(5) 842-845, 1973. 

Aquatic toxicity. EDTA has low aquatic toxicity, is not persistent in the environment due mainly to photodegradation of Fe(III), Co(III), and Mn(II) EDTA complexes, does not bioaccumulate, and does not need to be classified and labeled with an environmental symbol or risk phrase. 

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