Pollution Assessment Of Acid Volatile Sulfide And Heavy Metals In The Pearl River Estuary And Adjacent Aeras

As one of China’s four major estuaries, the increasingly serious heavy metalspollution problem of the Pearl River estuary can not be ignored. A large number ofexisting studies and reports indicate that the water and sediments of Pearl Riverestuary are polluted by many heavy metals. Heavy metals can accumulate and enrichin aquatic organismsand, and they may have potential biological toxicity to thoseorganisms, and even more serious is that they can enlarge their toxicity through thefood chain which is harmful to human health.In this paper, the contents, distribution and pollution of acid volatile sulfide (AVS)and simultaneously extracted metal (SEM) in surface sediments in the Pearl Riverestuary and adjacent areas are studied, and the potential ecological risk of heavymetals is assessed by SEM/AVS and SEM-AVS.The result shows that contents of AVS in surface sediments of Humen range from0.128to31.6mol/g with an average of8.52mol/g; Contents of AVS in surfacesediments of Lingding Yang range from1.86to14.4mol/g with an average of6.74mol/g; Contents of AVS in surface sediments in outer Lingding Yang range from0.576to2.35mol/g with an average of1.24mol/g; Contents of AVS in surfacesediments of Erzhou Island range from0.606to1.87mol/g with an average of1.15mol/g. Contents of AVS decrease from Humen, Lingding Yang to the adjacent areas,which vary in a large range.Pollution of sulfide occurs mainly in Humen and Lingding Yang.12percent ofstations in Humen are beyond the third class quality standards value.15percent ofstations in Lingding Yang are beyond the first class quality standards value.Contents of SEM in surface sediments of Humen range from0.367to3.74mol/g with an average of1.85mol/g; Contents of SEM in surface sediments ofLingding Yang range from0.699to2.72mol/g with an average of1.49mol/g;Contents of SEM in surface sediments in outer Lingding Yang range from0.432to0.761mol/g with an average of0.567mol/g; Contents of SEM in surface sediments of Erzhou Island range from0.430~0.634mol/g with an average of0.516mol/g. Contents of SEM decrease from Humen、Lingding Yang to the adjacent areas,which vary in a large range.SEM/AVS is below1in Lingding Yang, outer Lingding Yang and Erzhou Island.Heavy metals in these areas are basically have no adverse effects on aquatic life.SEM/AVS of P3、P13、P16、P19and P20in Humen is above1. There is not enoughAVS combination with heavy metals and the excess heavy metals may have potentialbiological toxicity. SEM/AVS of the rest stations in Humen is below1.Further assessment results by SEM-AVS show that SEM-AVS of P3、P13、P16、P19and P20in Humen are between0and5. Heavy metals in these stations may havea middle level of biology toxicity.