Toxic effects of the joint exposure of Cd and decabromodiphenyl ether on soil microbial population.

In order to make clear the toxic effects of the joint exposure of Cd and decabromodiphenyl ether (BDE-29) on soil microbial population. During the 35 days after exposure to moderate Cd concentration resulted in a significant increase in pseudomonas aeruginosa, the high Cd concentrations exerts an significantly inhibiting effect on the pseudomonas aeruginosa populations, similar trends were also observed in Actinomycete at lower and moderate Cd conenctration. The inhibition rate of fungi in Cd treatments did not have significant differences at all treatments. The order of inhibiting rate of culturable soil microbial populations under Cd pollution was proved to be: pseudomonas aeruginosa>actinomycetes>fungi. BDE-209 inhibited the growth of soil pseudomonas aeruginosa, fungin and Actinomycetepopulations, even at a low concentration. The population of the three soil microbes generally declined with increasing BDE-209 concentration following certain dose response relationships during the entire incubation period. The inhibition ratios were dependent on incubation time, indicating a notable time-effect trend. The inhibition of joint Cd and BDE-209 exposure on soil microbial population was stronger than that of either of the two chemicals at moderate level Cd and BDE-209. The inhibition ratios of three microbial populations increased with increasing Cd +BDE-209 concentration and incubation time following certain dose-response relationships and time-effect trends during the entire incubation period, respectively. The sensitivity of soil microbial population followed the order: pseudomonas aeruginosa>fungi >actinomycete.