Solubility of ion and trace metals from stabilized sewage sludge by fly ash and alkaline mine tailing

Stabilized sewage sludge （SS） by fly ash （FA） and alkaline mine tailing as artificial soil, to be applied on the ecological rehabilitation at mining junkyards, offers a potentially viable utilization of the industrial by-product, as well as solves the shortage of soil resource in the mine area. An incubation experiment with different ratios of SS and FA was conducted to evaluate the solubility of ions and trace elements from stabilized sewage sludge. Results showed that fly ash offset a decrease in pH value of sewage sludge. The pH of （C） treatment （FA：SS = 1：1） was stable and tended to neutrality. The SO4^2- and Cl^- concentrations of the solution in the mixture were significantly decreased in the stabilized sewage sludge by alkaline fly ash and mine tailing, compared to the single SS treatment. Stabilized sewage sludge by FA weakened the nitrification of total nitrogen from SS when the proportion of FA in the mixture was more than 50%. The Cr, Ni, and Cu concentrations in the solution were gradually decreased and achieved a stable level after 22 days, for all treatments over the duration of the incubation. Moreover stabilized sewage sludge by fly ash and/or mine tailing notably decreased the trace metal solubility. The final Cr, Cu, and Ni concentrations in the solution for all mixtures of treatments were lower than 2.5, 15, and 50 μg/L, respectively.     

中国典型河湖水体铅的水生生物安全基准与生态风险评价

采用物种敏感度排序法(SSR)对我国铅的淡水水生生物安全基准进行推导,并以太湖为例进行了流域水生生物安全基准推导。对于难以获得的本土生物毒性数据,开展了相应的毒性试验。获得了我国国家与太湖流域铅的水生生物安全基准值,基准最大浓度(CMC)分别为63.92、104.26μg·L-1,基准连续浓度(CCC)分别为1.21、4.06μg·L-1。同时,对我国主要河流以及太湖流域进行了铅的生态风险评价,联合概率曲线法显示影响5%水生生物种类的概率分别为66.22%和43.19%,熵值法则显示中国主要河流存在较大的铅暴露风险,因此,我国铅的潜在生态风险较大,主要河流与太湖流域存在铅污染问题。     

A comparison of statistical methods for deriving freshwater quality criteria for the protection of aquatic organisms

Species sensitivity distributions (SSDs) are increasingly used in both ecological risk assessment and derivation of water quality criteria. However, there has been debate about the choice of an appropriate approach for derivation of water quality criteria based on SSDs because the various methods can generate different values. The objective of this study was to compare the differences among various methods. Data sets of acute toxicities of 12 substances to aquatic organisms, representing a range of classes with different modes of action, were studied. Nine typical statistical approaches, including parametric and nonparametric methods, were used to construct SSDs for 12 chemicals. Water quality criteria, expressed as hazardous concentration for 5 % of species (HC₅), were derived by use of several approaches. All approaches produced comparable results, and the data generated by the different approaches were significantly correlated. Variability among estimates of HC₅ of all inclusive species decreased with increasing sample size, and variability was similar among the statistical methods applied. Of the statistical methods selected, the bootstrap method represented the best-fitting model for all chemicals, while log-triangle and Weibull were the best models among the parametric methods evaluated. The bootstrap method was the primary choice to derive water quality criteria when data points are sufficient (more than 20). If the available data are few, all other methods should be constructed, and that which best describes the distribution of the data was selected.     

Bioanalytical and instrumental analysis of thyroid hormone disrupting compounds in water sources along the Yangtze River

Thyroid hormone (TH) agonist and antagonist activities of water sources along the Yangtze River in China were surveyed by a green monkey kidney fibroblast (CV-1) cell-based TH reporter gene assay. Instrumental analysis was conducted to identify the responsible thyroid-active compounds. Instrumentally derived l-3,5,3′-triiodothyronine (T₃) equivalents (T₃-EQs) and thyroid receptor (TR) antagonist activity equivalents referring to dibutyl phthalate (DBP-EQs) were calculated from the concentrations of individual congeners. The reporter gene assay demonstrated that three out of eleven water sources contained TR agonist activity equivalents (TR-EQs), ranging from 286 to 293 ng T₃/L. Anti-thyroid hormone activities were found in all water sources with the TR antagonist activity equivalents referring to DBP (Ant-TR-EQs), ranging from 51.5 to 555.3 μg/L. Comparisons of the equivalents from instrumental and biological assays suggested that high concentrations of DBP and di-2-ethylhexyl phthalate (DEHP) were responsible for the observed TR antagonist activities at some locations along the Yangtze River.     

河北省邯郸市地表水体景观规划浅析

现阶段城市水体的研究主要是河流的治理,而没有考虑城市水体整体的生态规划及水体生态的整体 性,根据景观规划的原则及邯郸市的现实情况,对邯郸市内的地表水体进行连接,统一管理规划,达到生态和美学统一的作用.     

苯酚及其氯代物对大型溞的毒性效应和微观机理探讨

采用静态生物急性试验的方法,研究了5种酚类化合物对大型溞的急性毒性效应,并利用正辛醇/水分配系数(Kow)对实验测得的毒性数值进行了统计分析,得到了有效的毒性估测模型.研究结果表明,大型溞的幼溞接触不同化合物的不同浓度,活动会受到抑制,甚至死亡,苯酚、4-氯酚、2,4-二氯酚、2,3,4-三氯酚和五氯酚的48 h EC50分别为9.15、4.64、4.40、1.92、0.37 mg/L;根据化学物质对溞类的毒性评价标准,这5种化合物都属高毒物质,其中五氯酚具有极高毒性.另外,五氯酚对大型溞的致毒关键步骤不仅包括传输分配过程还有生化反应.     

太湖保护水生生物2,4-二氯苯酚基准研究

2,4-二氯苯酚(2,4-DCP)被纳入我国优先污染物名单,同时也是水环境中最常见的氯酚类化合物的一种,而太湖作为中国最大和污染最严重的淡水湖之一,需要针对2,4-DCP进行区域水质基准研究为太湖水质改善提供基础数据.通过太湖8种本土生物的急性毒性试验并两步外推法补充了相应的慢性毒性数据.结合文献数据建立该化合物的太湖水生生物毒性和pH数据库,依据协方差分析得到太湖急慢性双基准(CMC和CCC)的pH方程式.当pH=7.8时,通过传统物种敏感度分布法得到太湖CMC和CCC,分别为610.42μg·L~(-1)和9.80μg·L~(-1).此外,水质基准主要是基于实验室能培养、繁育、实验的水生生物的毒性数据推导而来的,和太湖实际生物区系比例难以一致,因此结合太湖生物区系和水质特征,利用物种权重敏感度分布法得到太湖CMC和CCC值分别为584.43μg·L~(-1)和6.83μg·L~(-1).本研究对科学管理区域水环境中污染物,实现水化学、生态完整性具有一定支撑,对我国2,4-DCP区域水质标准的制定有一定的参考价值.     

考虑物种权重校验保护太湖水生生物的铅基准

铅是一种有毒重金属元素,位列我国水中优先控制污染物"黑名单".我国水系众多,水生生物多样,研究保护区域水生生物的铅基准十分必要.太湖作为中国周边经济最发达、大中城市最密集且污染最严重的淡水湖泊之一,本研究选取8种太湖本土水生生物实验补充铅的急性毒性数据并两步外推得到慢性毒性数据.结合文献建立铅的本土毒性数据库,基于水体硬度对铅毒性的影响,建立硬度和毒性关系.考虑太湖生物区系和水质特征,采用物种权重敏感度分布方法,得到保护太湖水生生物铅的最大浓度基准值(CMC)和持续浓度基准值(CCC)值分别为50.04—58.87μg·L~(-1)和3.99—4.69μg·L~(-1);现行地表水铅的Ⅲ类标准限值(50μg·L~(-1))下受铅急性毒性和慢性毒性影响的生物比例分别为4.42%和23.00%.     

含磷材料对矿区铅镉污染土壤重金属形态转化的影响

以湖南郴州东江湖风景区矿区遗留地重金属污染土壤为研究对象,研究了3种含P材料,及其与蒙脱石的组合材料,对矿区土壤铅镉污染的修复效果.实验设6组处理,分别为P1组、P2组、P3组、P1 +M组、P2+M组、P3 +M组,通过添加5％的稳定剂,稳定2d后,分析土壤中铅镉的形态变化.实验结果表明:添加含P材料,及组合材料后,土壤中铅镉的离子交换态、铁锰结合态、有机结合态大幅度降低,残渣态显著升高.对Pb离子转化效果均在90.00％以上,Cd离子的转化效率相对较差,最优P1处理效果为74.20％.离子交换态的减少,有效地降低了重金属的生物有效性,有效地降低了环境风险.同时,含P材料均增加了土壤有效磷的含量,对矿区土壤的肥力也有一定提升.