蚯蚓扰动作用对原位污染土壤Cd、Cu、Zn全量和有效性变化的影响及其富集规律

针对我国土壤重金属污染严重问题,选取河北省保定市周边地区持续重金属污染的原位土壤与赤子爱胜蚓为研究对象,采用实地采样与室内培养相结合的方式,研究蚯蚓扰动作用对土壤重金属Cd、Cu和Zn全量与有效性变化的影响及蚯蚓对重金属的富集规律。主要结果如下,蚯蚓在供试土壤(清洁土与3种原污土)中培养至第14天时,不同供试土壤全量Cd、Cu和Zn含量较培养前均呈下降趋势,其中土壤全量Cd含量分别降低了40.48%、9.90%、0.89%和6.15%;土壤全量Cu含量分别降低了3.16%、8.16%、4.34%和7.74%;土壤全量Zn含量分别下降了2.27%、3.53%、3.34%和4.84%。供试土壤DTPA-Cd、DTPA-Cu和DTPA-Zn含量较培养前呈升高趋势,DTPA-Cd含量分别增加了29.41%、16.54%、14.33%和0.51%;DTPA-Cu含量分别增加了10.51%、1.26%、12.28%和5.30%;DTPA-Zn含量分别增加了44.99%、9.62%、7.97%和0.18%。另外,不同污染土壤下随培养时间的延长,蚯蚓体内Cd、Cu和Zn含量总体呈上升趋势。蚯蚓对Cd、Cu和Zn的富集能力表现为Cd>Zn>Cu。培养至第2天和第7天时,蚯蚓Cu含量与土壤全量Cu和DTPA-Cu含量均呈极显著正相关;培养至第14天时,蚯蚓Zn含量与DTPA-Zn含量呈显著正相关。

Changes of the total and DTPA-Metals (Cd,Cu,Zn) with disturbance functions and accumulations of matals in earthworm Eisenia fetida

In view of severe issues of metal contaminations in China, the study collected the historically metal-contaminated soils in fields from the vicinity areas of Baoding City, Hebei Province by the way of combination of the field samplings and indoor incubations, and to study the disturbances effects of earthworm(Eisenia fetida) on variations of total and available metal(DTPA) concentrations in soils, and analysis the accumulations of metals in earthworm bodies. The main results showed that the concentrations of the total Cd, Cu and Zn concentration in the tested soil were decreased after incubated the earthworms for 14 days(including the treatments of CK and three levels of metal-contaminated soils). In specifically, results indicated that the total-Cd concentrations in each soil samples were decreased by 40.48%, 9.90%, 0.89% and 6.15%, respectively; The total-Cu concentrations in soil were decreased by 3.16%, 8.16%, 4.34% and 7.74%, respectively; The total-Zn concentrations were decreased by 2.27%, 3.53%, 3.34% and 4.84%, respectively. The available DTPA-Cd, DTPA-Cu and DTPA-Zn concentration in each soil samples were increased compared with the CK group which was without earthworm incubation. In each soil samples, the DTPA-Cd concentrations were increased by 29.41%, 16.54%, 14.33% and 0.51%, respectively; DTPA-Cu increased by 10.51%, 1.26%, 12.28% and 5.30%, respectively; DTPA-Zn concentrations increased by 44.99%, 9.62%, 7.97% and 0.18%, respectively. In addition, the concentrations of Cd, Cu and Zn in earthworms were increased with the exposure time in different levels of contamination soils. The accumulations of metals in earthworms propensities for Cd, Cu and Zn was Cd>Zn>Cu. The regression relationships between soil metals and earthworms showed that the earthworm Cu concentrations was positively correlated with the total-Cu and DTPA-Cu in soils, respectively; The Zn concentrations in earthworm was positively correlated with DTPA-Zn contents after 14 days of exposure.