State Key Laboratory of Pollution Control and Resource Reuse, School of Earth Sciences and Engineering, School of the Environment, Nanjing University, Nanjing 210023, P. R. China.
College of Environment, Hohai University, Nanjing 210098, P. R. China.
Environ Sci Technol. 2020 Jun 2;54(11):6610-6620. doi: 10.1021/acs.est.9b06748. Epub 2020 Apr 10.
The fractions transformation and dissipation mechanism of Dechlorane Plus (DP) in the rhizosphere of soil-plant system were investigated and characterized by a 150-day experiment using a rhizobox system. The depuration, accumulation, and translocation of DP in rice plants were observed. The contributions of plant uptake, microbial degradation, and bound-residue formation to DP dissipation under the rhizosphere effect were modeled and quantified. The gradients of DP concentrations correlated well with microbial biomass in the rhizosphere ( = 0.898). The rhizosphere facilitated the bioavailability of DP (excitation) and modified the bound-residue formation of DP (aging). DP concentrations in roots were positively correlated with the labile fraction of DP in soil ( = 0.852-0.961). There were spatiotemporal variations in the DP fractions. Dissolved and soil organic carbon were important influences on fraction transformation. Contributions to total DP dissipation were in the following ranges: microbial degradation (8.33-54.14%), bound-residue formation (3.64-16.43%), and plant uptake (0.54-3.85%). With all of these processes operating, the half-life of DP in the rhizosphere was 105 days. The stereoselectivity of DP isomers in both rice and DP fractions in soil were observed, suggesting a link between stereoselective bioaccumulation of DP in terrestrial organisms and dissipation pathways in soil.
采用根盒系统进行了 150 天的实验，研究并表征了 Dechlorane Plus（DP）在土壤-植物系统根际中的转化和耗散机制。观察了 DP 在水稻植株中的净化、积累和迁移。建立并量化了植物吸收、微生物降解和结合残留形成对根际效应下 DP 耗散的贡献。DP 浓度梯度与根际微生物生物量相关性较好（=0.898）。根际促进了 DP 的生物可利用性（激发）并改变了 DP 的结合残留形成（老化）。根中 DP 浓度与土壤中 DP 的可利用分数呈正相关（=0.852-0.961）。DP 分数存在时空变化。溶解态和土壤有机碳是影响分数转化的重要因素。对总 DP 耗散的贡献范围如下：微生物降解（8.33-54.14%）、结合残留形成（3.64-16.43%）和植物吸收（0.54-3.85%）。所有这些过程共同作用下，DP 在根际中的半衰期为 105 天。观察到 DP 对映异构体在水稻和土壤 DP 分数中的立体选择性，这表明 DP 在陆地生物中的立体选择性生物积累与土壤中耗散途径之间存在联系。
