Accumulation of Halogenated Aromatic Hydrocarbons and Activities of Cytochrome P450 and Glutathione S-Transferase in Crabs (Eriocheir Japonicus) From Japanese Rivers

Abstract

Abstract-The hepatopancreases of freshwater crabs (Eriocheir japonicus) collected from three Japanese rivers (Barato, Shiribetsu, and Tone) were analyzed for planar halogenated aromatic hydrocarbons (HAHs), including polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (PCBs). The hepatic glutathione S-transferase (GST)-dependent enzyme activities in the crab hepatopancreas were also measured to examine their potential as biomarkers for the contaminants. Crabs from the Tone River, which runs through industrial, agricultural, and urban areas, have the highest concentrations of HAHs (4,100 pg/g fat weight), followed by those from the Barato River (2,430-2,970 pg/g fat weight), whereas crabs from the Shiribetsu River were relatively less contaminated (1,350-1,800 pg/g fat weight). Identification of numerous PCDD and PCDF congeners in crabs from all three rivers provided evidence that one of the major sources of PCDDs and PCDFs was waste incineration. In addition, crabs from the Barato and Shiribetsu Rivers were notably contaminated with 1,3,6,8-and 1,3,7,9-TeCDD congeners, which suggests that a possible source was chlornitrofen, which has been extensively used in paddy fields as a herbicide. Calculation of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin toxic equivalents (TEQs) showed that the causal contaminants of higher TEQs in crabs from the Tone River (94.7 TEQ picograms per gram fat weight) were PCDDs and PCDFs, although the most important contributor to the total TEQs was coplanar PCBs (49.95%). The crab hepatopancreas appeared to have abilities to transfer glutathione to 1-chloro-2,4-nitrobenzene (CDNB) and 3,4-dichloronitrobenzene (DCNB). The crabs with the highest TEQ levels showed the highest GST activities. The current results and our previous data lead us to conclude that cytochrome P450 and GST-dependent enzyme activities (benzo[a]pyrene hydroxylation and CDNB and DCNB conjugation) in freshwater crab hepatopancreases are likely to be useful biomarkers for the contamination of planar aromatic hydrocarbons such as benzo [a]pyrene, PCDDs, PCDFs, and coplanar PCBs.

Activity of Glutathione S-Transferase in the Hepatopancreas is not Influenced by the Molting Cycle in the Fiddler Crab, Uca pugilator

“…Hydrophobic pollutants, such as organochlorine compounds and polycyclic aromatic hydrocarbons, can readily accumulate in the tissues of crustaceans (Ishizuka et al 1998;Menone et al 2000;Eickhoff et al 2003). It conjugates potentially harmful electrophilic substances with endogenous reduced glutathione to protect other nucleophilic molecules, such as proteins and nucleic acids.…”

“…Hydrophobic pollutants, such as organochlorine compounds and polycyclic aromatic hydrocarbons, can readily accumulate in the tissues of crustaceans (Ishizuka et al 1998;Menone et al 2000;Eickhoff et al 2003). The correlation between enzymatic activity and contaminant accumulation and the induction of GST activity by organic contaminants have led to the suggestion of GST activity in the hepatopancreas of crustaceans as a biomarker for organic pollution (Ishizuka et al 1998;Gowland et al 2002;Arun et al 2006). Ishizuka et al (1998) reported the correlation between GST activity and the accumulation of organochlorines in the hepatopancreas of the freshwater crab, Eriocheir japonicus.…”

Polychlorinated-dibenzo-p-dioxins, -dibenzofurans and -dioxin-like polychlorinated biphenyls in aquatic organisms from lake Kasumigaura, Japan

“…The same study reported 1271 to 15 792 PCDD/DFs from sediments, 377 in Ono River, 1608 from paddy field around KUL and reference soil 2171 from Tokyo urban on pg/g dry weight basis. Crabs collected from Tone River had 1100 pg/g fat weight PCDD/DFs, 3000 pg/g co-planar PCBs and 94.7 pg/g TEQs [20]. As indicated before, Koise River, Ono River, Sakura River and Tone River downstream into the KUL and expected to deposit larger amount of toxic contaminants in to the KUL.…”

Non- and Mono-ortho Chlorinated Biphenyls

“…However, this does not rule out the possibility of drug induction in invertebrates. That is what a Japanese team [47] has shown in crabs by measuring glutathione S-transferase activity in hepatopancreas.…”