影响土壤重金属生物毒性的若干因子

Factors Affecting Biological Toxicity of Hea-vy Metals in Soils and Their Regulation.

本文应用发光细菌法探讨了土壤类型、粘土矿物、无定形金属氧化物、吸附剂对重金属纯溶液以及重金属污染土壤的降毒效应.红壤、砖红壤对Cu、Cd、Pb呈现负的降毒效应,而对As具有明显的降毒作用.黑土、黄棕壤对供试阳离子金属具有明显的降毒效应,对As降毒却不明显.试验证明粘土矿物及其组成是影响土壤重金属毒性的最基本因素.无定形氧化锰对供试阳离子金属的降毒能力大于无定形氧化铁,对As的效应二者则相反.不同吸附剂对Cu、Cd、Pb呈现基本相同的降毒顺序,即炉烟灰>活性炭>泥炭>干活性污泥,不同配比吸附剂对红壤添加性阳离子和东乡铜矿污染土壤均具有明显的降毒作用.添加吸附剂的东乡铜矿污染土壤随着土壤溶液毒性的消除,随之也消除或减轻了其对水稻种芽的急性毒害.

The detoxifying effects of soil types, clay minerals, amorphous metal oxides and adsorbents on heavy metal solution and heavy-metal-polluted soils were determinedin terms of a photobacteria approach. Red earths and lafosols had a negative effect on the toxicity reduction of Cu, Cd and Pb, but an evident reducing effect of them was found on the toxicity of As. Black soil and yellow brown earths had an obvious reducing effect on the toxicity of the cationic metals in the experiments, but they had no notable reducing effect on the toxicity of As. Experimental results showed that clay minerals and their composition were the most fundamental factors affecting the toxicity of heavy metals in soils. Amorphous manganese oxides were proved to have a greater detoxica-tion on the cationic metals than amorphous iron oxides, but their effects on As were quite contrary. The effects of different adsorbents on the detoxication of Cu, Cd and Pb were found in the following order: furnace dust> active carbon > peat > dry activated sludge. All applied adsorbents in different proportions were found to be significant in detoxifying the cationic metals added into red earth and soil polluted by Dongxiang copper ores. The acute poison symptoms of rice shoots in the ore-polluted scils were eliminated or alleviated with the adsorbents having been applied.