攀枝花公园土壤中钒的地球化学形态及潜在生态风险

GEOCHEMICAL SPECIATION AND POTENTIAL ECOLOGICAL RISK OF VANADIUM IN THE SOIL IN THE PANZHIHUA PARK

钒是人和动物必需的微量元素,但过量又会给动植物及人体健康造成损害。近年来随着钒矿的开采,土壤钒污染及其危害日益受到人们的重视。采用改进的BCR方法(按顺序提取元素形态的方法),系统测定旱季和雨季攀枝花公园土壤中钒的地球化学形态,研究土壤中钒地球化学形态的分布及变化特征,以此评价土壤钒污染及潜在生态危害。结果表明:土壤中不同形态钒的含量顺序为残渣态>可氧化态>可还原态>酸可溶态,旱季和雨季土壤中钒的形态变化不明显;攀枝花公园入口处各形态钒的质量分数均较高,与该处人员流动密度大有一定的关系,而在儿童游乐区、休闲区、休憩区各形态的钒无明显的高异常;采用中国土壤背景值计算得到的土壤中钒的污染指数较高,超标率为100%,而采用加拿大城市公园土壤中钒环境质量标准计算得到的污染指数较低,但仍有近一半的样点超标,雨季较旱季钒的污染指数高;通过风险评估编码方法得到的土壤中钒的生态风险为低风险等级,应引起注意。

Although Vanadium is essential to human, it is toxic to animals and plants if they are receive too much of it. Mining is one of the main causes for the increasing pollution of heavy metals in soil. Recently, people pay more and more attention to the pollution of vanadium in the soil. Soil samples were collected in the Panzhihua Park in dry season and rainy season respectively. Geochemical forms of vanadium in the soil were studied by improved BCR extraction procedure. In addition, the regional patterns of geochemical speciation and variety factors of vanadium were discussed. The pollution and potential ecological risk of vanadium in the soils were assessed. It was indicated that the chemical speciation of vanadium was characteristic of residual〉oxidisable 〉reducible〉acid soluble, and there was no clearly different speciation of vanadium in soil between dry season and rainy season. It was also showed that the high mass fraction of speciation of vanadium was in the entrance of the park, where the stream of people density was high than other places. While in children pleasure ground and rest area the high abnormity of vanadium is not obvious. According to Chinese soil background value, the pollution index of vanadium in soil in the park is high and exceeds standard rate of 100%0. While according to environmental quality standard of vanadium in soil of Canadian park, the pollution index is lower, but still have half of the samples over the standard. In addition, the pollution index is higher in rainy season than in dry season. Finally, the ecological risk of vanadium in the soil was low by Risk Assessment Code （RAC）, so attention should be paid to the vanadium pollution in the area.