Plastic Debris And Organophosphorus Additives In Wild Freshwater Fish Of The Pearl River Catchment

Plastics have been widely used to manufacture many kinds of living and industrial supplies due to its corrosion resistance,lightweight,portability and low cost.However,lacking of thorough waste recovery and treatment mechanism,these discarded plastics could enter into environment.Plastics degrade slowly and incompletely in environment and could be ingested by aquatic organisms leading to adverse effect on wildlife.The Pearl River Delta?PRD?is both an important freshwater ecosystem in south China and the centre of plastic-manufacturing industry.This study aims to investigate the distribution,shape,color and polymer composition of plastic debris in nine wild freshwater fish species from PRD,including silver carp,grass carp,Guangdong black bream,barbel chub,mud carp,common carp,prussian carp,redbelly tilapia and blotched Snakehead.The impacts of species-specific,seasonal and spatial difference on plastic abundance in gastrointestinal tracts of fish were discussed.Meanwhile,the accumulation of 12 organophosphorus esters?OPEs?additives including tris?2-chloroethyl?phosphate?TCEP?,tris?chloroiso-propyl?phosphate?TCPP?,tris?1,3-dichloro-2-propyl?phosphate?TDCPP?et al.,in dorsal muscle of freshwater fish species from PRD were investigated.This study could provide basic data to the ecological risk assessment of plastic and organophosphorus ester contamination in freshwater ecosystem in PRD.Main conclusions are as follows:?1?50.5%of the gastrointestinal tracts?GITs?of wild fish?n=279?contained plastic debris with mean abundacne of 7.0±23.8 items/individual.Fiber plastic was predominant?49.2%?in shape,following by fragment?37.5%?,film?11.2%?and sphere?2.1%?and transparent was most abundant in color.Twenty polymers were identified by micro-Fourier Transform Infrared Spectroscopy??-FTIR?in which polyethyleneterephthalate?PET,37.2%?,polyethylene?PE,23.1%?,ethylene-propylene copolymer?PE-PP,21.7%?and polypropylene?PP,10.5%?were predominant.?2?Obvious species-specific difference was observed in the distribution of plastic debris in wild fish.Redbelly tilapia had the highest detection frequency?75.0%?with highest abundance?27.4±54.0 items/individual?which was significantly higher than other species?p<0.05?,while blotched snakehead?25.0%,0.4±0.8?and common carp?15.8%,0.2±0.4?have the lowest abundance.Fiber and PET plastic were predominant in fish species except fragment and PE-PP in barbel chub.Plastic debris was more abundant in GITs of omnivorous fish than planktivorous,herbivorous and carnivorous fish and more abundant in bottom dweller than in mid-bottom water and top water dweller,indicating diet composition could be an important source of plastic debris.Seasonal variation was observed that the abundance of plastic debris in the fish was generally higher in dry season than in wet season.Nevertheless,no obviously seasonal difference was observed for the patterns of color,shape and polymer composition of the plastic debris implying that release of the plastic wastes in the PR catchment does not vary significantly all year around.?3?Except for TPP and TDBPP,10 OPEs were detected in dorsal muscle and the detection frequency was 46.9?TDCPP?-86.5?TBEP?%with?₁₀OPEs of 3.04-107.38ng/g lipid weight?lw?and mean concentration of 25.86±19.02 ng/g lw and TCPP,EHDPP,TBEP and TCEP were predominant.The?₁₀OPEs of redbelly tilapia was the highest?mean:37.91 ng/g lw?in which EHDPP was predominant while TCEP was predominant in prussian carp and TCPP in barbel chub,mud carp,silver carp and Guangdong black bream showing the species-specific differences of?₁₀OPEs.Concentration of TEP,TCEP,EHDPP and TCP in dorsal muscle showed negative correlation with body length while TCEP and TCP showed negative correlation with body weight,possibly due to the growth-dilution or metabolism of these OPEs in fish.