Distribution Pattern And Pollution Status Evaluation Of Trace Metals In A Sediment Core From South China Sea

This study analyzed the concentrations and settlement distribution of metals(V,Cr,Mn,Fe,Co,Ni,Zn,Cu,Ba and U)and total organic matter(TOC)in sediment core from the Northeast South China Sea.Lastly,we assessed the single risk level of metal and the sum pollution level of all metals in this research area by Ecological Risk Assessment(e.g.contamination factor(Cf)and pollution load index(PLI)).The main results are as follows:(1)Heavy metal pollution was not major problem in South China Sea sediments.In this study,the concentrations of the analyzed heavy metals i.e.,Cr,Pb,Cd in sediment core from South China Sea were below than the reference standard values.The concentration of trace metals in the sediment core from South China Sea were ranged from 0.291 ± 0.69 to 10.80 ± 1.26 ppm(avg.2.81 ppm)for Mn,50.53 ± 1.84 to 120.1 ± 0.67 ppb(avg.93.00 ppb)for V,60.65 ± 3.29 to 26.65 ± 3.89 ppb(avg.49.78 ppb)for Cr,63.77 ± 0.17 to 22.60 ± 1.35 ppm(avg.44.69 ppm)for Fe,25.41 ± 1.65 to 90.11 ± 1.64 ppb(avg.63.81 ppb)for Ni,16.93 ± 3.44 to 56.59 ± 1.44 ppb(avg.41.06ppb)for Cu,140.2 ± 2.44 to 396.9 ± 1.14 ppb(avg.238.10 ppb)for Zn,9.040 ± 0.86 to 35.02 ± 0.56 ppb(avg.21.91 ppb)for Pb,5.180 ± 0.21 to 7.910 ± 0.66 ppb(avg.6.412 ppb)for U and 307.4 ± 0.69 to 841.6 ± 0.79 ppb(avg.585.9 ppb)for Ba.The average trace metals concentration in the sediments core were decreased as Fe>Mn>Ba>Zn>V>Ni>Cr>Cu>Pb>U.Comparing to MSQ1 and MSQ2,the average content for all selected trace metals in the sediment core from South China Sea were very low than the standard scale value.Among all the depth in the sediment core samples,no one exceed the standard scale for metals,and the distribution of metals in sediment core had some variability.(2)According to Ecological Risk Assessment(e.g.contamination factor(Cf)and pollution load index(PLI)),the results indicated that the site was low risk for all studied heavy metals.The averaged Igeo values of metals in studied core sample were decreased in the order of Mn>Zn>Cu>Cr>Ni>Pb that was slightly different from the order of potential contamination factor of six heavy metals Mn>Zn>Cu>Ni>Cr>Pb.The order of potential contamination factor of six heavy metals was Mn>Zn>Cu>Ni>Cr>Pb.This result was slightly different from the order of the ecological risk index.(3)These results clearly indicated that the quality of the South China Sea sediments was unpolluted to low polluted.After evaluating all the pollution indicators in the studied sediment core,it can be concluded that the core was not polluted at all,and it showed very low contamination levels for the all indicators.