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Environmental assessment of fate, transport and persistent behavior of dichlorodiphenyltrichloroethanes and hexachlorocyclohexanes in land and water ecosystems
Ahmed, G.; Anawar, H. M.; Takuwa, D. T.; Chibua, I. T.; Singh, G. S. & Sichilongo, K.
Abstract
Many studies have investigated the contamination
level, spatial distribution, sources, chiral signals, and
potential ecological and public health risks of
dichlorodiphenyltrichloroethanes, its metabolites and the
isomers of hexachlorocyclohexane in the environment. This
study presents a critical review to provide updated knowledge
about the fate, persistence, long-range transport and
toxicity effects of dichlorodiphenyltrichloroethanes and
hexachlorocyclohexanes in the environment on the basis of
analytical data between 1990 and 2014. Highest levels were
found for dichlorodiphenyltrichloroethanes (200–9300 ng/
L) and hexachlorocyclohexanes (20–36,000 ng/L) with
mean values of 1000 and 5600 ng/L, which were 10 and 56
times higher than the European Community allowable
residual limit of 100 ng/L, respectively, in Lake Taihu
water of China obtained between 1999 and 2000. Levels of
dichlorodiphenyltrichloroethanes in sediments and fish
species were remarkably higher than hexachlorocyclohexanes.
The highest levels of dichlorodiphenyltrichloroethanes
in sediments were found up to
780–227,000 ng/g near a production factory in China and
20,000–5,463,000 ng/g in cattle dips disposal areas in
Australia. Out of 32 selected locations for common fish
species, tilapia had the highest mean concentration of
dichlorodiphenyltrichloroethanes up to 3800 ng/g in Noha
River of Japan in 2006. Dichlorodiphenyltrichloroethanes
and hexachlorocyclohexanes derive from agricultural
runoff, industrial and urban wastewater, etc., that ultimately
associate with soil and sediments. The carbon–carbon and
carbon–chlorine bonds in dichlorodiphenyltrichloroethanes
and hexachlorocyclohexanes provide them persistence,
lipophilicity and high binding affinity leading to bioaccumulation
in the receptor protein. High accumulation of
dichlorodiphenyltrichloroethanes and hexachlorocyclohexanes
causes mutagenic, carcinogenic and endocrine disrupting
toxicity effects to the humans and wildlife.
Keywords
Environmental fate; Persistence; Lipophilicity; Bioaccumulation; Ecological toxicity; Dichlorodiphenyltrichloroethanes– hexachlorocyclohexanes; River–stream
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