The Distribution And Transmission Of Microplastics In The Black-billed Gull Habitat And Main Foraging Food Chain

Microplastics are difficult to degrade,which can exist in the environment for a long time.They can absorb other hydrophobic organic pollutants,which will have serious impacts on the environment and organisms.Microplastics can reach the human body through the food chain and endanger human health.There are few studies on the pollution of microplastics in bird habitats,and the transmission of microplastics in organisms is relatively scarce.Research on microplastic pollution in bird habitats can provide scientific basis for the protection of important birds.In this study,the Larus saundersi distributed in 1,000-2 management station of the Yellow River Delta was used as the target species.The abundance,types and colors of microplastics in the habitat of Larus saundersi were initially identified by saturated sodium chloride flotation and Microscopic examination.In addition,the chemical composition of suspected microplastic particles was identified and analyzed using a microconfocus laser Raman spectrometer(Lab RAM HR Evolution)and a Field Emission Scanning Electron Microscope(FE-SEM).The abundance,type and distribution characteristics of microplastics in the sediments,food,and birds of Larus saundersi in the foraging grounds of 1,000-2 management station were revealed,and the transmission of microplastics in the substrate-food-birds was analyzed.The main findings are as follows:1?Characteristics of microplastics pollution in sediments of the Yellow River DeltaMicroplastics were prevalent in the surface sediments of the Yellow River Delta Larus saundersi feeding grounds.The distribution pattern of microplastics abundance in the surface sediments of the three sample lines was No.3 sample line > No.2sample line > No.1 sample line.The results of one-way ANOVA showed that there was no significant difference in the abundance of microplastics in the surface sediment among the three sample lines.The shape of microplastics was dominated by fibers(92.10%),the color was mostly light(transparent accounted for 54.23%),and microplastics with particle size between 500-1000 ?m were the most abundant,accounting for about 28.86% of the total.2?Characteristics of microplastics pollution in food of Larus saundersi in the Yellow River DeltaMicroplastic pollution is widespread in crabs and clamworms.The average abundance of microplastics in crabs and sandworms was 0.38 ± 0.02 microplastics per g and 1.06 ± 0.04 microplastics per g.The distribution pattern of microplastics in the three sample lines was sample line 1>sample line 2>sample line 3.The results of one-way ANOVA showed that the abundance of microplastics in crabs in sample line1 was significantly different from that in crabs in sample line 3(P<0.05),while there was no significant difference between sample line 2 and both;the abundance of microplastics in sandworms in all three sample lines was not significantly different.The microplastics in crabs and sandworms were mainly fibers,and the proportion was above 80%.The particle size distribution of microplastics in crabs and sandworms was mostly concentrated in the range of 0.5-1 mm,and the color was mostly dark.3?Characteristics of microplastics pollution in the gastrointestinal tract of Larus saundersi in the Yellow River DeltaThe average abundance of microplastics in the bird's body was 4.45 ± 0.11 per individual,the average abundance of microplastics in the bird's stomach was 2.80 ±0.09 per individual,and the average abundance of microplastics in the bird's intestine was 1.65 ± 0.07 per individual.The average abundance of microplastics in the bird's body weight was 0.12 ± 0.02 /g,the mean abundance of microplastics in the bird's stomach was 0.93 ± 0.03 /g,and the abundance of microplastics in the bird's intestine was 0.76 ± 0.02 /g.The Pearson correlation analysis revealed that there was no significant correlation between the bird's body weight and the detection of microplastics,indicating that the intake of microplastics may not increase with the increase of body weight.4?Microplastic pollution transfer in sediment-food-birdClamworms have the ability to enrich microplastics in sediments.Through food chain relationships,clamworms can transfer microplastics from their bodies to higher trophic levels,resulting in widespread microplastic contamination in crab and Larus saundersi.Microplastic transfer along the food chain has a biologically dilutive effect,which is opposite to the shellfish-fish microplastic transfer effect.5?Two main types of microplastics were identified: polypropylene(PP)and polyethylene(PE).The electron microscopy results showed that the surface of the microplastics showed different degrees of corrosion.