太湖不同营养水平湖区沉积物理化性质和磷的垂向变化

利用SMT标准测试程序对太湖3个不同营养水平湖区表层10 cm柱状沉积物进行磷赋存形态的垂向分析,并在此基础上讨论了沉积物有机质总量(w(OM)),细颗粒组成与磷赋存形态间的相关关系.结果表明,研究区各采样点沉积物的w(TP)平均值为437～1 650 mg/kg,最高为1 809 mg/kg; w(OM)平均值为17.93～38.76 mg/g;沉积物颗粒组成以粉砂和粘粒为主,占总量的49.64%～83.57%.不同湖区沉积物磷形态的垂向分布规律不同,总体上TP,无机磷(IP),铁铝结合态磷(Fe/Al-P)表现出在表层富集的现象, 钙结合态磷(Ca-P)和有机磷(OP)随深度的变化不大; w(OM)自表层向下逐渐降低. 无机磷占沉积物中总磷的比例较大,且其含量与Fe/Al-P的含量密切相关.Fe/Al-P占TP的比例随沉积物污染程度的增加而升高,是与人类活动密切相关的;有机质总量与OP显著相关;粘粒比例随污染程度的增加逐渐增大.      

Distribution and incorporation mode of the herbicide MCPA in soil derived organo-clay complexes

The incorporation of xenobiotics into soil, especially via covalent bonds or sequestration has a major influence on the environmental behavior including toxicity, mobility, and bioavailability. The incorporation mode of 4-chloro-2-methylphenoxyacetic acid (MCPA) into organo-clay complexes has been investigated under a low (8.5 mg MCPA/kg soil) and high (1000 mg MCPA/kg soil) applied concentration, during an incubation period of up to 120 days. Emphasis was laid on the elucidation of distinct covalent linkages between non-extractable MCPA residues and humic sub-fractions (humic acids, fulvic acids, and humin). The cleavage of compounds by a sequential chemical degradation procedure (OH^?, BBr₃, RuO₄, TMAH thermochemolysis) revealed for both concentration levels ester/amide bonds as the predominate incorporation modes followed by ether linkages. A possible influence of the soil microbial activity on the mode of incorporation could be observed in case of the high level samples. Structure elucidation identified MCPA as the only nonextractable substance, whereas the metabolite 4-chloro-2-methylphenol was additionally found as bioavailable and bioaccessible compound.     

New DDT inputs after 30 years of prohibition in Spain. A case study in agricultural soils from south-western Spain

This study provides information on the current status of contamination by DDT in agricultural soils in south-western Spain. A recent use of technical DDT in at least 17% of the soils was found based on the values (<1) of the ratio Rp,p^′/p,p^′=[p,p^′-DDE+p,p^′-DDD]/[p,p^′-DDT]. According to the ratio Ro,p^′/p,p^′=[o,p^′-DDT]/[p,p^′-DDT], a dicofol type contamination was detected in about 27% of the soils. A wide range of concentrations was observed (0.08-11.1 ng/g d.w.) regardless of the type of crop soil. Enantiomeric fractions (EFs), based on the chiral analysis of o,p′-DDT residues differed from the racemic value (0.500) in most soils but they were not correlated with the study variables [DDTs], SOM, Rp,p^′/p,p^′ and Ro,p^′/p,p^′. Given the health risks posed by DDT, our findings support how the environmental control of legacy pollutants such as DDT cannot be neglected.     

Effective Efficiency as a Tool for Sustainable Water Resources Management1

Abstract: The sufficiency and usefulness of Effective Efficiency (EE) as a water resources index is shown through conceptual formulation of a generalized EE and practical applications. Two EE models are proposed: one is based on water quantity and the other on quantity and quality, with the possibility of considering water reuse (recycling) in both. These models were developed for two scales: the first is called Project EE and the second Basin EE. The latter gives the influence of the project on the water resources systems of the basin while the former does not make such connection to the whole basin. Such considerations give proper signals as to the adequacy of any intervention to increase efficiency. A crucial distinction is made between depletion and diversion water savings. Classical Efficiency (CE) models are analyzed and compared with the various EE models. CE results in values that are less than EE because of not considering water reuse and water quality in its calculation. Some authors, pointing to these problems – particularly the first problem – have advocated the use of hydrological “fractions” instead of efficiency concepts. This paper defends the use of a proper efficiency model such as EE and suggests putting an end to the use of the CE indicators. To test the models, they are applied to five cases of irrigation and city water use in the United States and Egypt. The analysis of the results demonstrates all the points mentioned above and the potential of the EE models to adequately describe the water resources efficiency and sustainability at a location.     

离体模型预测鱼体肝脏清除速率：鲑鱼肝细胞和肝脏S9组分的比较

将离体肝细胞和肝脏S9组分用于获取鱼类的体外生物转化数据可以优化模拟评估对化学物质的生物富集作用。然而涉及2种方式之间的直接对比的研究却几乎没有。本研究采用冷藏保存的鲑鱼肝细胞来测定对于6种多环芳烃(PAHs)的体外本征清除速率。我们运用测定结果推测体内本征清除速率,并将其作为输入值输入一种充分搅匀的肝脏模型中来预测肝清除速率。将事先由体外灌流肝脏测定的速率作为参考来评价预测结果。在2种竞争结合的假说前提下,由鲑鱼肝细胞测出的肝清除速率与实现的测定结果基本一致(6种多环芳烃中的5种都保持在2.1倍差异以下)。尽管多环芳烃的高代谢率是可能的原因之一,这些发现与之前由肝脏S9组分得出的结果相似。对苯并芘这一种化合物而言,由S9数据得出的体内本征清除速率是由肝细胞得出结果的10倍左右,这一结果可能是由细胞吸收速率造成的传播限制引起的。尽管苯并芘的结果差异较大,由任何一种体外测试方法得出的体内本征清除速率结果通常是一致的。这些结果显示离体肝细胞和肝脏S9组分2种系统均可用于优化鱼类的生物富集评估,尤其对于体外反应速率较高的情况。不同系统在化工领域的应用性是否相同则需要进一步的研究工作。
精选自Kellie A. Fay, Patrick N. Fitzsimmons, Alex D. Hoffman, John W. Nichols. Comparison of trout hepatocytes and liver S9 fractions as in vitro models for predicting hepatic clearance in fish. Environmental Toxicology and Chemistry: Volume 36, Issue 2, pages 463–471, July 2017. DOI: 10.1002/etc.3572
详情请见http://onlinelibrary.wiley.com/wol1/doi/10.1002/etc.3572/full
     

Metal (Cu, Cd and Zn) removal and stabilization during multiple soil washing by saponin

The influence of multiple saponin washing on copper, cadmium and zinc removal and stability in three types of soils (loamy sand, loam, silty clay) was investigated. Distribution of metals and their mobility measured as the ratio of exchangeable form to the sum of all fractions in soils was differential. After single washing the highest efficiency of metal removal was obtained in loamy sand (82-90%) and loam (67-88%), whereas the lowest in silty clay (39-62%). In loamy sand and loam metals had higher mobility factors (44-61% Cu, 60-76% Cd, and 68-84% Zn) compared to silty clay (9% Cu, 28% Cd and 36% Zn). Triplicate washing led to increase both efficiency of metal removal and percentage content of their stable forms.In consequence, fractional patterns for metals before and after treatment changed visibly as a result of their redistribution. Based on the redistribution index, the most stable metal (mainly in residual and organic fractions) after triplicate washing was Cu in loamy sand and loam. For silty clay contaminated with Cd, effective metal removal and its stabilization required a higher number of washings.     

Sorption of 17α-ethinyl estradiol, bisphenol A and phenanthrene to different size fractions of soil and sediment

The potential for negative effects caused by endocrine disrupting chemicals (EDCs) release into the environment is a prominent concern and numerous research projects have investigated possible environmental fate and toxicity. However, their sorption behavior by size fractions of soil and sediment has not been systematically represented. The sorption of bisphenol A (BPA), 17α-ethinyl estradiol (EE2) and phenanthrene (Phen) by different size fractions of soil and sediment were investigated. Sorption isotherms of EE2, BPA, and Phen by size fractions of soil (SL) and sediment (ST) were well fitted to the Freundlich model. The positive correlation between EE2, BPA and Phen sorption capacity (log K_d) of size fractions and their organic carbon (OC) content suggests that OC of size fractions in SL and ST should regulate sorption, while the surface area (SA) of size fractions may not account for sorption of EE2, BPA and Phen. Each size fraction of ST had higher sorption capacity (K_d or K_OC) of EE2 and BPA than that of SL due to their difference in the polarity of organic matter (OM) between terrestrial and aquatic sources. Sorption capacity logK_d for size fractions of SL and ST did not follow the order: clay > silt > sand due to the difference in OM abundance and composition between the size fractions. Large particle fractions of ST contributed about 80% to the overall sorption for any EE2, BPA, and Phen. This study was significant to evaluate size fractions of soil and sediment as well as their associated OM affecting EE2 and BPA sorption processes.     

pH值对海陆交互相土壤镉纵向迁移转化的影响

为揭示土壤pH值影响下海陆交互相土壤镉(Cd)纵向迁移转化规律,共布设18组土壤剖面,测定90组海陆交互相不同深度土壤中的pH值及重金属镉含量,运用地质累积指数和潜在生态风险指数法对Cd污染程度进行评价,采用相关分析识别土壤pH值对土壤Cd迁移转化的影响程度.结果表明:广州市南沙区土壤多属于中度-强污染,具有高潜在生态...     

太湖地区几种水稻土团聚体颗粒组中PAHs的分布及其环境意义

以太湖地区代表性的青紫泥、黄泥土、白土等3种水稻土为研究对象,采用低能量分离-分散法提取得到不同粒径的团聚体颗粒组,用HPLC测定了本土和分离得到的团聚体颗粒组中16种PAHs的含量.结果表明,供试水稻土不同粒径的团聚体颗粒组中PAHs含量分布存在差异,PAHs总含量以＜2μm粒径的团聚体颗粒组最高,其次是200～2000μm粒径的团聚体颗粒组,PAHs在这2个团聚体颗粒组有明显富集现象(富集系数为1.25～3.92);而20～200μm和2～20 μm粒径的团聚体颗粒组中PAHs含量小于本土,呈现亏缺现象(富集系数为0.64～0.88).考虑到不同粒径团聚体颗粒组的相对组成,水稻土中PAHs主要分布于20～200μm和200～2000μm 2个团聚体颗粒组中,而在＜2μm粒径的团聚体颗粒组中最少.PAHs在不同粒径的团聚体颗粒组中的含量分布与其总有机碳、腐殖质碳、胡敏酸碳的含量有关,并在很大程度上受芳构化疏水性有机物含量的控制.因此,水稻土不同粒径团聚体颗粒中有机碳及其组分的性质影响着这些团聚体颗粒组分对PAHs的吸持与固定.     

温度波动对城市有机生活垃圾高温厌氧消化工艺影响

模拟由于加热失败导致温度从55℃突降到20℃(室温左右),且在20℃时持续时间分别为1h、5h、12h和24h,对高温厌氧消化处理城市有机生活垃圾工艺的影响进行了实验研究.温度突降以及恢复所需时间均在2h以内.正常状态下有机负荷为8.0g·(L·d)^-1,停留时间为15d.结果表明,温度突降后,产气量几乎降为0,总挥发性脂肪酸(VFA)和乙酸、丙酸含量快速积累,pH值也随之下降.但系统较高的缓冲能力使得pH值在正常范围内波动,并不影响反应器的运行.随着持续时间的延长,产甲烷菌等微生物的衰减上升,导致其产甲烷恢复时间延长.高温条件下温度波动不但影响产甲烷过程而且影响水解和发酵过程.但整个反应在温度突降后可以恢复,说明厌氧高温微生物对温度变化具有较好的恢复能力.