Biomagnification Effect Of Dechloranes In Food Web Of Dalian Bay

Dechloranes are a typical class of chlorinated flame retardants.Currently,Dechlorane plus(DP)and related compounds(Mirex,Dec602,Dec603,Dec604 and DP isomers syn-DP and anti-DP)are widely used in coatings,plastic and rubber materials,electronic equipment housings and polymer materials.Dechloranes has the typical characteristics of persistent organic pollutants.During producing,using,discarding,recycling and final disposal,there are many ways to enter the environmental medium,and then pose a potential threat to human health through the food web.However,there are few studies on these compounds in the food web,most of them have reported the existence of dechloranes in the environment.In this study,Dalian Bay was selected as the research area.A total of 303 samples of 9 species of fish,5 species of crustaceans,8 species of mollusks,and plankton were selected as the research objects.The trophic relationship between the main organisms was analyzed using stable nitrogen and carbon isotopes.A linear regression model between the fat equivalent concentration of the dechloranes in different biological species and the trophic level was established,and the distribution characteristics and nutrient amplification effect of the dechloranes in Dalian Bay organism were analyzed.The results show,he results showed that among all the tested species,the pollution levels of the five dechloranes were:Mirex(0.92-16 ng/g fat weight(1w))>DP(1.61-5.34 ng/g 1w)>Dec602(0.189-4.949 ng/g 1w)>Dec603(0.262-1.910 ng/g 1w)>Dec604(0.017-0.329 ng/g).From the detection rate,Dec602(99.3%)>Mirex(95.4%)>Dec603(91.7%)>DP(90.1%)>Dec604(9.6%).Among vertebrates and invertebrates,Mirex and anti-DP account for a large proportion of total dechloranes.Among vertebrates,Mirex is the main dechloranes,accounting for 32.83%-57.74%;in invertebrates,anti-DP is the main dechloranes,accounting for 19.12%-46.82%.In this study,the fanti value in all organisms is between 0.58-0.69,the average value is 0.65,the fanti value between different species is not much different,the average value is slightly lower than the fanti value in North American products(0.75-0.8).It is equivalent to our country the fanti value(approximately 0.6)in the commodities.Through calculation,the trophic level of the food web in Dalian Bay is 3,the trophic level magnification factor(TMF)of Mirex is 3.09,and the TMF of Dec602 is 3.388.In this study,the pollution degree of dechloranes in Dalian Bay was at an average level compared with existing studies.Among vertebrates and invertebrates,Mirex and anti-DP accounted for a large proportion of the total dechloranes.fanti value is comparable to China’s commercial value,indicating that dechloranes have a similar degree of degradation,bioaccumulation or biotransformation in marine organisms in Dalian Bay.Mirex and Dec602 have a significant trophic amplification effect in the food web in the Dalian Bay area,and other substances do not have a significant trophic amplification effect.