Distribution Of Microplastics And Its Accumulation In Zooplankton In The Yellow Sea And East China Sea

Microplastics(MPs)is used to describe the marine debris that are composed of plastics and have the size range from 1?m to 5mm,and MPs pollution in marine environment is an issue of global concern in recent years.Previous studies have shown MPs has been ubiquitous in the marine environment.China's coastal waters are the main areas of plastic waste discharged into the marine environment,but it is still poorly understood of the pollution status of MPs in the Yellow Sea and the East China Sea.Moreover,it has been shown that MPs will enter the marine food chain,and influence on marine animals to varying degrees.It is generally known that zooplankton is an indispensable part in the marine ecosystem as hub of material and energy cycle from primary production to higher trophic level in marine food chain,the effect of MPs on the zooplankton will inevitable indirectly affect the marine food chain and marine ecosystems.This study assesses density,type,and temporal trends of MPs in surface waters and abundance and composition of MPs in zooplankton in the Yellow Sea and the East China Sea.The results show that the plastic debris is widely distributed in the surface waters of the Yellow Sea and East China Sea,and most of them are MPs.In the East China Sea,the concentration of MPs is between 0.011 to 2.198 pieces/m3 and the average is 0.310 pieces/m3.The size of plastic debris are in the range between 178.6--21936.46?m,which the 88.58% of plastics in the range of 500--5000?m.The main form of MPs are foam(68.39%)and fragments(15.02%).The common color of MPs are white(71.99%)and colorized(18.47%).The common chemical composition of MPs are 45.45% Polyethylene,34.55% Polypropylene and 5.45% Polystyrene.In the Yellow Sea,the concentration of MPs between 0.019 pieces/m3 to0.812 pieces/m3 and the average is 0.134 pieces/m3.The size of plastic debris are in the range between 353.37---44993.57?m,which the 80.83% of plastics in the range of 500--5000?m.The main form of MPs are fragments(80.22%),film(5.54%),fibrous(9.54%)and foam(4.70%).The common color are transparent(including translucent)83.69%,white(8.33%)and colorized(7.11%).The common chemical compositions are Polyethylene(55.93%),Polypropylene(32.20%)and Polystyrene(6.78%).In the Yellow Sea and the East China Sea,MPs are ubiquitous in vivo of zooplankton.Usually,Amphipoda and Cladocera have the low average encounter rates.On the contrary,the other zooplankton has higher average encounter rates,such as Chaetognatha,Medusa,Euphausiacea,Luciferida and Thaliacea.In the East China Sea,the average encounter rates of the majority zooplankton is 15%--40%,but 5%--30% in the Yellow Sea.In the East China Sea,the abundance of MPs in common zooplankton taxon are: 0.11--80.63 pieces/m3 in Copepod with the average 8.34 pieces/m3,0.03—44.18 pieces/m3 in Jellyfish with the average 4.95 pieces/m3,0.03--9.57 pieces/m3 in Chaetognaths with the average 1.72 pieces/m3,0.02--18.14 pieces/m3 in Euphausiacea with the average 1.27 pieces/m3 and 0.16--11.01 pieces/m3 in Lucifer with the average 1.06 pieces/m3.Similarly,in the Yellow Sea,the abundance of MPs in common zooplankton taxon are Copepod(0.01—21.12 pieces/m3 and the average 2.40 pieces/m3),Euphausiacea(0.04—21.12pieces/m3 and the average 1.38 pieces/m3),Chaetognaths(0.08--9.26 pieces/m3 and the average 0.72 pieces/m3),Siphonohore(0.18—55.34 pieces/m3 and the average 3.50 pieces/m3).In general,the fibrous MPs accounted for the major part in zooplankton.In the East China Sea,The length of fibrous MPs from different zooplankton groups are between 18.12—3762.88?m and the average length is 291.08?m.The main chemical components of the MPs are Polymerized-oxidized organic material(35.90%)and Polyester(25.64%).Similarly,in the Yellow Sea,The length of fibrous MPs are between 10.25—996.75?m and the average length is 258.99?m.The main chemical components are Polymerized-oxidized organic material(21.88%)and Poly(1-Octen)(21.88%).The main conclusions of this study as follows,(1)Microplastics are universal exists in the surface waters of the Yellow Sea and the East China Sea.There is high concentration of MPs in the coastal areas of the coastal cities and the middle area of the Yellow Sea and the East China Sea.With a few exceptions,MPs' average concentration is higher in the East China Sea than in the Yellow Sea,which means that the MPs pollution situation in East China Sea is more serious.(2)Compared with other regions of the world,the concentration of MPs in the Yellow Sea and the East China Sea is still at intermediate level,but compared other reports in the East China Sea waters,the concentration of MPs has increased.(3)Microplastics are universal exists in intracorporal of zooplankton in the Yellow Sea and the East China Sea,which means,the MPs ingested by zooplankton is common phenomenon in nature.(4)Zooplankton may ingested MPs directly from the environment,or digested the prey contained MPs.It's indicate that the MPs will transferred in the marine food chain,and MPs has potential effects on marine communities and marine ecosystems.(5)Fibrous MPs occupied the main part of plastics in zooplankton may cause of high density fibrous plastics in seas,or it's difficult to excrete once MPs into the intracorporal of zooplankton.(6)The abundance of MPs in zooplankton is obviously higher than that in the surface waters of the Yellow Sea and the East China Sea.In the zooplankton of higher trophic level,the abundance of MPs is relatively more.This indicate that zooplankton has accumulation of micro plastic.