Fate of ah receptor Agonists during biological treatment of an industrial sludge containing explosives and pharmaceutical residues
Fate of ah receptor Agonists during biological treatment of an industrial sludge containing explosives and pharmaceutical residues
复制标题
DOI：
10.1007/bf02979656
复制
发表时间：
2004-01-01
影响因子：
5.8
通讯作者：
Engwall, M
中科院分区：
文献类型：
--
作者：
Gustavsson, LK;Klee, N;Engwall, M
目标、范围和背景。瑞典从2005年开始禁止有机废物沉积。由于瑞典每年产生100万吨污泥，而焚烧能力无法满足需求，因此必须在更高程度上引入其他污泥管理方法。两种生物处理替代方案是厌氧消化和堆肥。不同的氧气浓度会导致不同的微生物降解途径，从而导致消化或堆肥残留物的质量不同。因此，有必要研究不同氧状态下的污泥处理，以便跟踪化合物的降解和毒性的变化。本研究对含有炸药和药物残留物的工业污泥进行厌氧消化或堆肥处理，研究其毒性变化。硝基芳香族化合物是药物和炸药的主要成分，众所周知会引起细胞毒性和遗传毒性。然而，关于含有硝基芳族化合物和任何相关二恶英类活性的污泥的数据很少。因此，我们研究了处理前后的污泥，以便使用两种二恶英类化合物的生物测定法来检测 Ah 受体 (AhR) 激动剂水平的变化。在小型反应器中以半连续方式对工业污泥进行厌氧消化或堆肥处理。每天取出与补料体积相同的体积并储存在-20℃。生物测定的样品制备是通过使用有机溶剂萃取，然后用硅胶或硫酸净化，产生两个级分。将级分溶解在 DMSO 中并在生物测定中进行测试。使用转染的 H4IIE 大鼠肝癌 pGudluc 细胞的 DR-CALUX 测定法和 RTL-W1 虹鳟鱼肝细胞的 EROD 诱导测定法测量二恶英样活性。结果和讨论。生物测定表明，污泥中含有的 AhR 激动剂的 TCDD 当量 (TEQ) 水平高于瑞典其他污泥类型。此外，厌氧消化后耐酸部分的TEQ值显着增加，导致厌氧反应器中明显形成耐酸TEQ。对发酵家庭垃圾的研究也报告了类似的结果。两种生物测定的效果存在很大差异，RTL-W1 EROD 测定中的 TEQ 水平高于 DR-CALUX 测定中的 TEQ 水平。这可能是由于大鼠肝细胞的新陈代谢比鳟鱼肝细胞更快，或者是由于污泥中 AhR 激动剂的敏感性不同。 GC/FID 分析还表明，污泥中含有高浓度的硝基芳族化合物。建议硝基芳香族代谢物，例如芳香胺和硝基苯胺，可能是观察到的生物测定效应的候选物。还发现污泥样品中的AhR激动剂具有挥发性。结论。污泥含有相当高浓度的挥发性 AhR 激动剂。厌氧消化后耐酸 AhR 激动剂的增加值得进一步研究这些化合物的化学和毒性特性以及这一观察结果背后的机制。建议和展望。这项研究指出了在评估污泥处理毒性变化时使用不同类型的机制特异性生物测定的好处，其中二恶英类活性的测量可能是一个有价值的工具。为了使用 DR-CALUX 测定研究污泥中化合物的顽固特性，暴露时间可以在 6 至 24 小时之间变化。必须研究厌氧处理中形成的耐酸 AhR 激动剂的特性，以便选择最合适的污泥管理方法。
Goal, Scope and Background. Sweden is meeting prohibition for deposition of organic waste from 2005. Since 1 million tonnes of sludge is produced every year in Sweden and the capacity for incineration does not fill the demands, other methods of sludge management have to be introduced to a higher degree. Two biological treatment alternatives are anaerobic digestion and composting. Different oxygen concentrations result in different microbial degradation pathways and, consequently, in a different quality of the digestion or composting residue. It is therefore necessary to study sludge treatment during different oxygen regimes in order to follow both degradation of compounds and change in toxicity. In this study, an industrial sludge containing explosives and pharmaceutical residues was treated with anaerobic digestion or composting, and the change in toxicity was studied. Nitroaromatic compounds, which are the main ingredients of both pharmaceutical and explosives, are well known to cause cytotoxicity and genotoxicity. However, little data are available concerning sludge with nitroaromatics and any associated dioxin-like activity. Therefore, we studied the sludge before and after the treatments in order to detect any changes in levels of Ah receptor (AhR) agonists using two bioassays for dioxin-like compounds.Methods. An industrial sludge was treated with anaerobic digestion or composting in small reactors in a semi-continuous manner. The same volume as the feeding volume was taken out daily and stored at -20degrees C. Sample preparation for the bioassays was done by extraction using organic solvents, followed by clean up with silica gel or sulphuric acid, yielding two fractions. The fractions were dissolved in DMSO and tested in the bioassays. The dioxin-like activity was measured using the DR-CALUX assay with transfected H4IIE rat hepatoma pGudluc cells and an EROD induction assay with RTL-W1 rainbow trout liver cells.Results and Discussion. The bioassays showed that the sludge contained AhR agonists at levels of TCDD equivalents (TEQs) higher than other sludge types in Sweden. In addition, the TEQ values for the acid resistant fractions increased considerably after anaerobic digestion, resulting in an apparent formation of acid resistant TEQs in the anaerobic reactors. Similar results have been reported from studies of fermented household waste. There was a large difference in effects between the two bioassays, with higher TEQ levels in the RTL-W1 EROD assay than in the DR-CALUX assay. This is possibly due to a more rapid metabolism in rat hepatocytes than in trout hepatocytes or to differences in sensitivities for the AhR agonists in the sludge. It was also demonstrated by GC/FID analysis that the sludge contained high concentrations of nitroaromatics. It is suggested that nitroaromatic metabolites, such as aromatic amines and nitroanilines, are possible candidates for the observed bioassay effects. It was also found that the AhR agonists in the sludge samples were volatile.Conclusions. The sludge contained fairly high concentrations of volatile AhR agonists. The increase of acid resistant AhR agonist after anaerobic digestion warrants further investigations of the chemical and toxic properties of these compounds and of the mechanisms behind this observation.Recommendation and Outlook. This study has pointed out the benefits of using different types of mechanism-specific bioassays when evaluating the change in toxicity by sludge treatment, in which measurement of dioxin-like activity can be a valuable tool. In order to study the recalcitrant properties of the compounds in the sludge using the DR-CALUX assay, the exposure time can be varied between 6 and 24 hours. The properties of the acid-resistant AhR agonists formed in the anaerobic treatment have to be investigated in order to choose the most appropriate method for sludge management.