| Abstract:Inductively coupled plasma emission spectrometer(ICP-AES) and inductively coupled plasma mass spectrometer(ICP-MS) were used to determine the contents of eight heavy metals,ie.As,Cu,Cd,Cr,Hg,Ni,Pb and Zn in the soil of mangrove wetland at Zhanjiang Bay.Single factor index,Nemerow index and geoaccumulation index were used for pollution assessment.The sources of heavy metals were investigated by correlation analysis and factor analysis.The results obtained are as follows:Except for Ni,the average mass fractions for the other seven heavy metals do not exceed the national soil environmental quality standard(GB15618-2018),but Ni,Zn,Cu,Hg,As and Cd exceed the environmental background values for Guangdong latosol,while As,Ni,Hg and Zn exceed the national environmental standard seriously.The Nemerow indexes for eight heavy metals range from 0373 to 22576,with an average of 3378,which means a serious pollution state.The single factor pollution indexes for eight heavy metals in turn are ranked as follows:Ni>Hg>Zn>Cd>As>Cu>Pb>Cr.The evaluation results of geoaccumulative indexes are consistent with those of Nemerow indexes,indicating that Hg,Zn and Ni are important factors affecting soil environmental quality in the study area.Viewing from the stations,the stations of Beiyacun and Guanhaichanglang in the north of the Bay,and Shiqiaocun in the west are serious polluted,about 33% of the total number of stations mainly attribute to Cd,Hg and Zn pollution.Statistical analysis results showed that,except for Ni,there are significant correlations among As,Cu,Cd,Cr,Hg,Pb and Zn,while the correlation between Ni and other elements is not significant.Based on the field survey results,it is inferred that the heavy metal pollutions mainly derive from the input of human activities,such as industrial pollution,ship sewage,aquaculture sewage,domestic sewage,and agricultural non-point source pollution,next from the input of natural factors. |
