三种重金属元素在鹭卵中富集特征的初步研究

2004年4～6月，采集了合肥地区大蜀山、肥西圆通山、肥东太子山集群繁殖的夜鹭、小白鹭、池鹭和牛背鹭鸟卵及组织样品，用原子吸收法测定了卵壳、内容物及组织中Cd、Pb、Cr的残留量.结果表明，4种鹭卵壳、内容物及组织的绝大多数样品中均检出相当高水平的Cd、Pb和Cr残留量，且卵壳和骨骼是重金属富集的主要场所，表明通过卵壳可以排出体内部分重金属污染物.卵壳中重金属显著高于卵内容物，卵壳中重金属残留量为Cr>Pb>Cd，4种鹭卵壳中重金属残留量的种间差异都极其显著，Cr残留水平的种间波动幅度最大，池鹭卵壳中的最高，牛背鹭的最低；Pb的种间波动幅度相对较小，Cd的种间波动幅度最小；而卵内容物中3种重金属残留量的种间差异都不显著，Cr残留量种间波动幅度最大，池鹭卵内容物中，Cr含量最高，牛背鹭卵内容物中没有检出；Pb的种间波动幅度相对较小，Cd的种间波动幅度最小.由于鹭的卵壳取样容易，可用作重金属污染物的指示物，监测和评价湿地生态系统中重金属的污染状况.

Enrichment characteristics of heavy metals in heron eggs

In this study,the eggs and tissues of black-crowned night heron,little egret,Chinese pond heron and cattle egret were sampled from the Dashu,Yuantong and Taizi mountains in Hefei areas of Anhui Province in April to June 2004,and the residual amounts of Cd,Pb and Cr in the samples were determined by atomic absorption spectrophotometry.The results showed that the test heavy metals could be detected at high levels in the eggshell,egg contents,and tissues of most samples.Eggshell and bone were the two main sites for heavy metals enrichment.Eggshell had significantly higher residues of the heavy metals than egg contents,implying that heavy metals could be excreted by eggshells.The residues of heavy metals in eggshell ranked as Cr>Pb>Cd,and had significant differences among species.Of the three heavy metals,Cr showed the most variation among species,being the highest in eggshell of Chinese pond heron and the lowest in that of cattle egret,but in egg contents,there was no significant difference among species.The variation of Cr residues among species was the second,being the highest in the egg contents of Chinese pond heron but not detected in that of cattle egret.The residues of Pb among species varied little.Since eggshell was easy to collect,it was practical to use it as the indicator to assess the pollution status of wetlands.