Organochlorine concentrations in aquatic organisms from different trophic levels of the Sundarbans mangrove ecosystem and their implications for human consumption

• Published in: Environmental pollution (1987) Vol. 251; pp. 681 - 688
• Main Authors: Borrell, Asunción, Tornero, Victoria, Bhattacharjee, Dola, Aguilar, Alex
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.08.2019
• Subjects: Bangladesh; Food safety; Human consumption; Mangrove ecosystem; POP; Trophic web; POP; Trophic web; Human consumption; Bangladesh; Food safety; Mangrove ecosystem
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2019.04.120

The Sundarbans, a highly biodiverse tropical ecosystem stretching across India and Bangladesh, is also the largest mangrove forest in the world. Organochlorine compounds (OCs) have been extensively used for agriculture and sanitary purposes in the region. OCs can accumulate in biological tissues and biomagnify in organisms through food webs, for which reason they reach high concentrations in top predators. Because marine food webs are long and marine predators are extensively used in the region as human food, assessment of potential health-related risks caused by OC pollution is in order. This study is the first to determine the concentration of PCBs in fish and crustaceans from the Sundarbans mangroves, their accumulation trends through the food web, and the potential toxicological risk that their consumption poses to humans. DDT concentrations, which had already been assessed in the region, were also determined. The median concentrations ranged from below detection limits to 176.3 ng g−1 lipid weight for tDDT and 275.9  ng g−1 for PCBs. Overall, these concentrations were lower than those usually observed in other regions of the world, apparently as a result of the interplay of several factors: low environmental organochlorine inputs, the physical and climatic characteristics of an ecosystem dominated by high temperatures in a highly flushed ecosystem that dilutes and rapidly disperses pollutants, and the comparatively short food chain lengths that, similarly to other mangrove ecosystems, characterize the Sundarbans. Organochlorine concentrations were 2-3 orders of magnitude lower than commonly accepted tolerance levels, so their consumption do not pose a sensible risk to the population. However, concentrations of DDT in dry fish from retail markets were higher because this compound is used for pest control during fish processing. Potential risks involved in this practice likely outweigh potential benefits, so it is recommended that this compound is substituted by less hazardous alternatives. [Display omitted] •DDTs and PCBs were identified in organisms from the Sundarbans mangrove ecosystem.•Levels found were lower than those in wildlife from other mangrove ecosystems.•Levels in edible fish are not considered to pose a risk for human consumption.•Food chain length in the mangrove ecosystem was found to be remarkably short.•No relationship was found between organochlorine concentrations and trophic levels. Organochlorine concentrations in aquatic organisms from the Sundarbans mangrove ecosystem are low, not related to trophic level, and do not pose a risk to human consumption.