Evaluation of different methods for assessing bioavailability of DDT residues during soil remediation.
Evaluation of different methods for assessing bioavailability of DDT residues during soil remediation.
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DOI：
10.1016/j.envpol.2018.02.082
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发表时间：
2018-07
影响因子：
8.9
通讯作者：
Jie Wang;Allison R. Taylor;Chenye Xu;Daniel Schlenk;Jay Gan
中科院分区：
文献类型：
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作者：
Jie Wang;Allison R. Taylor;Chenye Xu;Daniel Schlenk;Jay Gan
与总化学浓度相比，生物利用度是衡量疏水性有机污染物（HOCs）对污染土壤或沉积物中生物群风险的更好方法。许多不同的生物利用度评估方法已经被引入来评估修复处理的有效性。然而，迄今为止，很少对不同的方法进行相互评价，导致方法选择的混乱。本研究采用固相微萃取（SPME）和聚乙烯被动采样（PE）检测游离化学物质浓度（Cfree）， Tenax解吸和同位素稀释法（IDM）测量化学物质可及性等四种不同的生物利用度估算方法，平行估算了添加不同黑碳吸附剂后历史污染土壤中DDT残留（DDXs）的生物利用度。同时测定了蚯蚓（Eisenia fetida）体内的生物积累量。活性炭或生物炭在0.2 ~ 2%的浓度下可使蚯蚓对ddx的生物积累减少83.9 ~ 99.4%，而多壁碳纳米管的影响有限（4.3 ~ 20.7%）。虽然所有方法都能正确预测黑碳修正后DDX生物利用度的变化，但被动采样法的预测更为准确。利用估计的生物利用度和经验BCFs预测的蚯蚓脂质中DDXs的水平与实验得出的组织浓度密切匹配。然而，当有效DDX水平较低时，Tenax和IDM高估了生物利用度。研究结果表明，被动采样法和生物可及性法均可用于评估土壤修复效率，且方法选择具有灵活性。虽然面向可访问性的方法提供更好的灵敏度和更短的采样时间，但被动采样器可能更具优势，因为它们具有更好的性能和可计算性。
Compared to the total chemical concentration, bioavailability is a better measurement of risks of hydrophobic organic contaminants (HOCs) to biota in contaminated soil or sediment. Many different bioavailability estimation methods have been introduced to assess the effectiveness of remediation treatments. However, to date the different methods have rarely been evaluated against each other, leading to confusions in method selection. In this study, four different bioavailability estimation methods, including solid phase microextraction (SPME) and polyethylene passive sampling (PE) aiming to detect free chemical concentration (Cfree), and Tenax desorption and isotope dilution method (IDM) aiming to measure chemical accessibility, were used in parallel to estimate in bioavailability of DDT residues (DDXs) in a historically contaminated soil after addition of different black carbon sorbents. Bioaccumulation into earthworm (Eisenia fetida) was measured concurrently for verification. Activated carbon or biochar amendment at 0.2–2% decreased earthworm bioaccumulation of DDXs by 83.9–99.4%, while multi-walled carbon nanotubes had a limited effect (4.3–20.7%). While all methods correctly predicted changes in DDX bioavailability after black carbon amendment, passive samplers offered more accurate predictions. Predicted levels of DDXs in earthworm lipid using the estimated bioavailability and empirical BCFs matched closely with the experimentally derived tissue concentrations. However, Tenax and IDM overestimated bioavailability when the available DDX levels were low. Our findings suggested that both passive samplers and bioaccessibility methods can be used in assessing remediation efficiency, presenting flexibility in method selection. While accessibility-oriented methods offer better sensitivity and shorter sampling time, passive samplers may be more advantageous because of their better performance and computability forin situdeployment.