Bioaccumulation Profiles of Polychlorinated Biphenyl Congeners and Organochlorine Pesticides in Ganges River Dolphins

Abstract

Abstract-Isomer-specific concentrations of polychlorinated biphenyls (PCBs) including non-, mono-, and di-ortho-substituted congeners, DDT and its metabolites, hexachlorocyclohexane (HCH) isomers, chlordane compounds, and hexachlorobenzene (HCB) were determined in river dolphin blubber and prey fishes collected during 1993 through 1996 from the River Ganges in India. Concentrations of organochlorines were also measured in the milk and liver of dolphins, benthic invertebrates, and sediments. The DDTs and PCBs were the predominant compounds found in dolphin tissues and fish that comprise the diet of dolphins. Concentrations of DDTs and PCBs in the blubber of dolphins were in the range of 30 to 120 and 1.5 to 25 g/g, lipid weight, respectively. Pentaand hexachlorobiphenyls collectively accounted for 68 to 80% of the total PCB concentrations in river dolphins. Hexachlorobiphenyl congener 138 (2,2Ј,3,4,4Ј,5Ј-) was the most abundant in dolphin blubber and prey fishes. The isomer/congener pattern of PCBs and organochlorine pesticides suggested that there is less metabolism due to cytochrome P450 enzymes in Ganges river dolphins than in marine or terrestrial mammals. The mean 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs) estimated in river dolphin blubber was greater than those that can cause adverse effects in mink. Comparison of organochlorine concentrations in river dolphins with those of the values reported for samples analyzed during 1988 through 1992 suggested that the contamination by these compounds has increased in the River Ganges.

Accelerating population decline of Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis)

“…), the Amazon River dolphin (Inia geoffrensis), the Irrawaddy dolphin (Orcaella brevirostris) and the tucuxi (Sotalia fluviatilis), also face comparable challenges of long-term survival (Reeves et al, 1991;Reeves and Chaudhry, 1998;Smith and Smith, 1998;Smith et al, 2001;Martin et al, 2004;Braulik, 2006), but demographic data for these species are still extremely limited. Although specific threats facing these freshwater cetaceans may vary geographically in their importance, common threats include substantial loss of effective habitat (Reeves et al, 1991;Braulik, 2006), increasing concentrations of persistent organic pollutants in cetacean tissue (Senthilkumar et al, 1999), and incidental fisheries by-catch (Martin et al, 2004). The drastic decline of the Yangtze finless porpoise in two decades as a result of rapid industrial and economic growth reveals how uncontrolled environmental deterioration threatens the future of freshwater cetaceans despite the potential for the massive scale of the Yangtze system to buffer anthropogenic impacts.…”

Preliminary Hazard Assessment of Polychlorinated Biphenyls, Polybrominated Diphenyl Ethers and Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans to Yangtze Finless Porpoise in Dongting Lake, China

“…Polychlorinated biphenyls, PBDEs, and PCDD/Fs have been reported in cetaceans. Concentrations of PCBs have been found ranging from several to hundreds of g/g lipid weight in the oceanic and river cetaceans [1,10,14,[22][23][24]. The range of PBDE concentrations was reported from the ng/g to g/g level in the cetaceans studied [15,[25][26][27].…”

“…River dolphins are unique species among cetaceans in that they inhabit freshwaters. They have been threatened, however, by degradation and destruction of riverine habitat [1]. The populations of some river dolphins are rapidly declining and endangered [1].…”

“…They have been threatened, however, by degradation and destruction of riverine habitat [1]. The populations of some river dolphins are rapidly declining and endangered [1]. Apart from habitat destruction, chemical pollution also has been a serious threat to the health of river dolphin populations ( [2,3]; http://www.onefish.org/servlet/CD SServlet?statusϭND02NDA1LjgzODMmNj1lbiYzMz1kb 2N1bWVudHMmc2hvd0NoaWxkcmVuPXRydWUmMzc9a W5mbwϳϳ#koinfo).…”

The silent spermatozoon: are man-made endocrine disruptors killing male fertility?

“…These pollutants include a variety of industrial solvents and by-products including biphenyls and other compounds postulated to be estrogenic endocrine disruptors. 43,44 The substantial increase in world population, particularly in regions exposed to high concentrations of potential estrogenic pollutants, argues strongly against a deleterious effect of these pollutants on male fertility.…”