Focused on dioxin pollution problem of Chinese mitten crab (Eriocheir sinensis), scientists from Shanghai academy of agriculture sciences conduct explored transfer and accumulation behavior of 17 dioxins and 12 dioxin-like PCBs (DL-PCBs) in the food web of farmed Chinese mitten crabs after 3 years study, and find the key causes of dioxins and DL-PCBs pollution in farmed Chinese mitten crab. The results provide crucial insight to prevent and reduce contamination of crab by dioxins and DL-PCBs.

Dioxins are the first batch of persistent organic pollutants (POPs) in Stockholm Convention, which are persistent and highly toxic, and can pose significant risks to human health and environment in global. Chinese mitten crab is an aquatic animal, which tend to accumulate dioxins from environmental (water and sediment) due to its bottom-dwelling and omnivore. Clarifying the sources and transfer routes of dioxins and DL-PCBs in the food web of farmed crabs is of great significance for dioxin prevention and control during farm culture.

Based on dioxins monitoring in farmed Chinese mitten crabs in the lower reaches of the Yangtze River, the research team conducted a 3-year study in crab food web of a typical farm. The study found that dominant routes of dioxins accumulation in crabs were transferred for the sediment-snail-crab and sediment-crab chains, whereas DL-PCBs is mainly transferred through consumption of inputs feeds and snails. Transfer model calculations indicated that 45.6% was attributed to direct transfer from the aquaculture environment and 46.5% to the consumption of snails. Consumption of feed material accounted for nearly all of the total DL-PCBs TEQ, divided as 58.2% from feed and 41.8% from snails. Snails as a key intermediate organism contributing significantly to dioxins accumulation in crabs were first identified. These finding provide crucial insight to prevent and reduce contamination of crab by dioxins and DL-PCBs.

Rao Qinxiong and Wang Xianli were the first authors of the paper and Prof. Song Weiguo was the corresponding author. The present research was funded by the Shanghai Agriculture Applied Technology Development Program, China and Outstanding team of Shanghai Academy of Agricultural Sciences.

posted by Wang Xianli from Institute of Agro-food Standards and Testing Technology