北部湾沿海经济区水稻根系土重金属元素潜在生态风险评价

Potential Ecological Risk Assessment of Heavy Metals from Rice Rhizosphere Soil in Beibu Gulf Economic Zone

为了解北部湾沿海经济区水稻根系土中重金属生态风险等级,采用Hakanson潜在生态危害指数法对70个采样点Hg、As、Cd、Pb、Cu和Zn 6种重金属进行污染的潜在生态风险评价。结果表明:研究区根系土综合潜在生态风险指数变化范围58.84～417.88,平均值118.49,整体平均水平处于轻微生态风险水平。生物有效性评价结果显示,根系土中各元素生物可利用性大小顺序为Cd>Zn>Pb>Cu>Hg>As。Cd、Pb和As在水稻籽实中出现了不同程度的超标,主要与工业活动和施肥灌溉有关。

Hakanson potential ecological risk index is used to assess the potential environmental risk of six heavy metals（As,Cd,Cu,Hg,Pb and Zn） in 70 rice rhizosphere soil samples.The samples are collected from Beibu Gulf Economic Zone.The results show that the comprehensive potential ecological risk index of these metals ranges from 58.84 to 417.88,with an average value of 118.49.All of the potential ecological risk indexes show low ecological risk and indicate that the rhizosphere soil is slightly contaminated.The order of bioavailability for heavy metals is CdZnPbCuHgAs.The content of Cd,Pb and As in some rice seeds is above the national standard,due to the industrial activity,fertilization and irrigation.