我国不同土壤铜的生物可利用性及影响因素

选取我国8种典型类型土壤,运用生态毒理学的方法研究土壤中铜的生物可利用性。选取大麦根长和生物量为反应终点,运用计算Dose-response的S-Logistic模型计算出引起反应终点比对照减少10%和50%时的土壤总铜浓度(EC50、EC10)和外源铜浓度(EC10a、EC50a)。结果表明,由根长数据得出的EC10a、EC50a为最佳的分析8种土壤铜的生物可利用性的指标。8种土壤的EC10a在25.3～170.2mg/kg,EC50a在58.1～429.5mg/kg,数值分布范围较宽,说明8种土壤中铜的生物可利用性存在差异,生物可利用性的大小依次为:漳州>海口>烟台>武威>西藏>上海>铜仁>洛阳。ECX与pH和CaCO3呈显著正相关,而这两个指标都是土壤酸碱度的表征,说明土壤的酸碱性能显著影响土壤中铜的生物可利用性。土壤对铜的最大吸附量xmax与ECxa呈显著正相关性,提示土壤对铜的吸附能影响铜的生物可利用性。

Bioavailability and Impact of Copper in Various Soils

Eight kinds of soil samples were collected to study the bioavailability of copper by eco -toxicological method. Barley root length and biomass were selected as endpoint, model of S-Logistic was used to calculate the threshold value of effective concentration of total Cu concentration (EC50 arid EC10) and added Cu concentration (EC10a and EC50a ) causing 10% and 50% inhibition of barley root length and biomass compared with unamended control samples. Results showed that EC10a and EC50a were the best parameters to analyze the bioavailability of copper. The wide range of EC10a from 25.3 to 170.2mg/kg and EC50a from 58.1 to 429.5mg/kg indicated that Cu bioavailability of eight soils has differences. There were obvious positive linear relationship between ECX and pH and CaCO3, results showed that acid and alkaline characters of soil can affect Cu bioavailability significantly. Soil maximal absorbance Xmax has an obvious positive-linear relationship with ECxa, which indicated that soil adsorption of Cu could affect Cu bioavailability.