【摘要】 中国农田土壤铅（Pb）、砷（As）复合污染严重,二者的交互作用可影响彼此的移动性与生物有效性。探索Pb、As复合污染条件下,Pb-As交互作用影响Pb、As移动性及生物有效性的机理对土壤重金属复合污染防治和保护人体健康具有重要意义。以小白菜（Brassica campestris L.）为供试作物,设置不同质量分数Pb(0、125、250 mg·kg^-1)、As(0、30、60mg·kg^-1)两两组合处理（共计9个处理）,通过盆栽试验研究Pb-As交互作用对小白菜生长及小白菜中Pb、As生物有效性的影响。研究发现,低浓度Pb、As复合污染对小白菜生长无显著影响（P>0.05）,而在As60(As质量分数60mg·kg^-1,以下类推)、As60Pb125(As、Pb质量分数分别为60 mg·kg^-1,125 mg·kg^-1,以下类推)和As60Pb250高浓度处理下,与对照相比小白菜地上部干质量分别下降了7.9%、6.0%和15%。处理As30Pb125和As60Pb125与Pb125相比,孔隙水中Pb浓度分别上升了2.8倍和3.7倍。类似地,处理As30Pb125和As30Pb250与As30相比,孔隙水中As浓度均上升了1.2倍。小白菜对Pb的富集能力强于As,Pb-As交互作用可促进小白菜对As的积累,处理As30Pb125与As30相比,小白菜地下部对As的累积量增加了42.3%。不同处理下As在孔隙水中均主要以H₂AsO₄^-形态存在,而Pb在孔隙水中的主要存在形态及丰度具有差异性,这可能是导致小白菜As的积累量与孔隙水中As含量呈显著正相关（P<0.05）,而小白菜Pb的积累量与孔隙水中Pb含量无显著相关性（P>0.05）的原因。综上,高质量分数Pb、As复合污染可抑制小白菜生长,Pb-As交互作用对孔隙水中Pb/As的移动性具有协同影响而对小白菜中Pb/As积累的影响具有差异性。更多还原

【Abstract】 Combined contamination of Pb and As in farmland soil is serious and the interactive effects between Pb and As can affect each other’s mobility and bioavailability. Under the combined contamination of Pb and As, it is of great significance for the prevention and control of combined contamination of soil heavy metal and human health by exploring the mechanism of Pb-As interaction affecting the mobility and bioavailability of Pb and As. In this paper, pot experiment was conducted to study the interactive effects of Pb and As on the growth of Brassica campestris L. and the bioavailability of Pb and As in Brassica campestris L. Nine treated soils with different combined contamination levels of Pb(0, 125, 250 mg·kg^-1) and As(0, 30, 60 mg·kg^-1) were used for pot experiment. The results showed that low mass fractions of the combined contamination of Pb and As had no significant effect on the growth of Brassica campestris L.（P>0.05）, but under the high mass fractions treatments of As60, As60 Pb125 and As60 Pb250, compared with CK, the dry biomass of the aboveground part of Brassica campestris L. decreased by 7.9%, 6.0% and 15%, respectively. Compared with the treatment Pb125(Pb mass fraction is 125 mg·kg^-1,the same below), concentrations of Pb in the pore water under the treatments As30 Pb125(As mass fraction is 30 mg·kg^-1 and Pb mass fraction is 125 mg·kg^-1, the same below)and As60Pb125 incereaed by 2.8 times and 3.7 times, respectively. Similarly, compared with the treatment As30,concentrations of As in the pore water under the treatments As30 Pb125 and As30Pb250 incereaed by 1.2 times and 1.2 times,respectively. Brassica campestris L. showed higher enrichment ability of Pb than As and the interactive effects of Pb and As enhanced As accumulation in Brassica campestris L. Compared with the treatment As30, the accumulation of As in the underground part of Brassica campestris L. increased by 42.3%. As mainly existed in the form of H₂AsO₄^- in pore water under all the treatments,while the main Pb species and their abundances in pore water were different under different treatments. This may be the reason why the accumulations of As in the aboveground and underground parts of Brassica campestris L. were significantly and positively correlated with the As concentration in pore water（P<0.05） but there was no significant correlation between the accumulation of Pb in the aboveground and underground parts of Brassica campestris L. and the Pb concentration in pore water（P>0.05）. In all, high mass fractions Pb and As combined contamination inhibited the growth of Brassica campestris L. The mobility of Pb and As exerted synergistic effects under co-contaminated conditions in pore water while the accmulatity of Pb and As in Brassica campestris L.showed difference.更多还原