摘要
为开展海口市城乡环境梯度带不同区域土壤重金属富集特征,采集海口市城市中心区、城乡交错区、农村区、自然区等4个不同区域的农用地土壤剖层样品,测定Cd、Hg、As、Pb、Cr、Cu、Ni、Zn等8种重金属含量,通过剖面土壤重金属的垂直分布迁移特征、重金属与理化指标相关性、重金属富集系数等分析海口市土壤重金属富集特点。结果表明:表层土壤Cd、Pb、Zn含量平均值均大于深层土壤,重金属存在不同程度的累积效应。土壤pH与Cd含量呈显著正相关,土壤pH对Cd重金属富集程度影响较大。土壤有机质(SOM)与Hg、Cr、Cu、Zn、Ni含量呈正相关,表层、中层相关性强于底层,表层土壤SOM对重金属富集有明显影响。各重金属富集系数大于1.2的点位比例从高到低为Cd(70.0%)、Hg(41.7%)、As(36.7%)、Pb(28.3%)、Zn(21.7%)、Cu(18.3%)、Ni(18.3%)、Cr(15.0%)。海口市农用地土壤重金属富集程度表现出一定的距离梯度变化特征,即随着距离城市中心区距离的增加,8项土壤重金属富集程度呈逐渐下降的趋势。自然区仅Cd呈现富集现象,其他7项重金属未发现富集点位。Cd、Hg、As土壤重金属富集系数涉及范围大,Cd城市中心区富集系数大于8的点位数量远超城乡交错区和农村区,Hg富集系数大于2的点位仅位于城市中心区和城乡交错区。Cd富集系数大于1.2的点位比例远超其他7个重金属项目,城乡环境梯度的覆盖度最大,区域性富集特点明显,且有30%点位富集系数大于4,土壤富集程度较强,应引起关注。
In order to investigate the enrichment characteristics of heavy metals in soil of different urban-rural environmental gradient zones in Haikou,agricultural surface soil samples were collected from four different urban-rural environmental gra-dient zones in Haikou,including the urban center,urban-rural transitional zone,rural area,and natural area.The concentration of eight heavy metals were measured,including Cd,Hg,As,Pb,Cr,Cu,Ni,Zn.The enrichment characteristics of heavy met-als in soil of Haikou were analyzed through the vertical distribution and migration characteristics of heavy metals,the correla-tion between heavy metals and physicochemical indicators,and the enrichment coefficient of heavy metals.The results showed that the average contentration of Cd,Pb,and Zn in surface soil was higher than that in deep soil,and heavy metals had varying degrees of cumulative effects.There was a significant positive correlation between soil pH and Cd content,and soil pH had a significant impact on the degree of Cd heavy metal enrichment.Soil organic matter(SOM)was positively correlated with the content of Hg,Cr,Cu,Zn,and Ni.The correlation between layer A and layer B was stronger than that of layer C.Surface soil SOM had a significant impact on heavy metal enrichment.The proportion of sites with heavy metal enrichment coefficients greater than 1.2 ranged from high to low was Cd(70.0%),Hg(41.7%),As(36.7%),Pb(28.3%),Zn(21.7%),Cu(18.3%),Ni(18.3%),and Cr(15.0%).The enrichment degree of heavy metals in agricultural land soil in Haikou showed a certain distance gradient variation feature,with the increase of distance from the urban center,the enrichment degree of eight soil heavy metals showed a gradually decreasing trend.Only Cd showed enrichment in the natural area,and no enrichment points were found for the other 7 heavy metals.The enrichment coefficients of Cd,Hg,and As soil heavy metals involved a wide range.The points with enrichment coefficients greater than 8 for Cd in urban central areas far exceeded that in ur-ban-rural and rural areas.The points with enrichment coefficients greater than 2 for Hg were only located in urban central areas and urban-rural transitional areas.The proportion of points with Cd enrichment coefficients greater than 1.2 far ex-ceeded the other seven heavy metal projects.The coverage of Cd enrichment in urban and rural environmental gradients was the highest,and the regional enrichment characteristics were obvious.In addition,the enrichment coefficient of 30%Cd points was greater than 4,indicating a strong soil Cd enrichment degree,which should be paid attention to.
作者
吴姬
王婧
符式锦
WU Ji;WANG Jing;FU Shijin(Hainan Ecological Environmental Monitoring Center,Haikou,Hainan 571126,China)
出处
《热带作物学报》
北大核心
2025年第2期503-513,共11页
Chinese Journal of Tropical Crops
基金
海南省自然科学基金项目(No.421QN0970)。
关键词
城乡环境梯度带
土壤
重金属
富集
urban and rural environmental gradient zone
soil
heavy metals
enrichment
