PAHs in surface sediments from coastal and estuarine areas of the northern Bohai and Yellow Seas, China

Polycyclic aromatic hydrocarbon (PAH) concentrations and their risks in surface sediments (n = 35) collected from coastal and estuarine areas of the northern Bohai and Yellow Seas, China, were investigated in 2008. Total concentrations of PAHs ranged from 52.3 to 1,870.6 ng/g dry weight. The greatest concentrations were observed in the Dou River of Tangshan where waste water from small factories is discharged into the river without treatment. At other locations, municipal sewage was the primary contributor of PAHs. Regional differences in concentrations of PAHs in sediments are related to human activities. Concentrations of PAHs were significantly correlated with concentrations of organic carbon in sediments. The patterns of relative concentrations and types of PAHs observed and knowledge of the potential sources, as well as the results of a principal component analysis, are consistent with the primary sources of PAHs in sediments of the northern Bohai Sea and Yellow Sea, being derived from the high-temperature pyrolytic processes such as combustion of fossil fuel. While concentrations of PAHs at most locations did not exceed the effects range median stated by the numerical effect-based sediment quality guidelines of the United States, concentrations of PAHs at some locations were similar to or greater than the effects range low.     

喀斯特石漠化过程中土壤重金属镉的地球化学特征

喀斯特石漠化是喀斯特背景下的土地退化.文章对喀斯特高原区贵州省清镇市王家寨峰丛洼地同一流域内不同类型石漠化、不同等级石漠化以及不同干扰方式石漠化土壤重金属镉的含量变化及其空间分布特征进行了研究.结果表明:研究区土壤Cd含量在0.034～0.635 mg·kg-1之间,平均值为0.243 mg·kg-1.其中,黑色石灰土Cd含量普遍高于黄壤,且存在极显著性差异(p≤0.01).土壤Cd含量总体随石漠化程度的加深而呈降低趋势,但除强度石漠化和轻度石漠化之间有显著性差异外(p≤0.05),其他石漠化等级之间无显著性变化.不同干扰方式石漠化之间,土壤Cd含量表现为开垦＜放牧＜火烧＜樵采,其中,开垦与火烧、开垦与樵采在对土壤Cd含量的影响上存在显著性差异(p≤0.05).土壤Cd含量在不同坡位间无明显变化规律,也无显著差异.研究区土壤Cd含量受土壤组分、有机质、pH和CEC等诸多因素的影响,其中,土壤有机质、pH和土壤组分是其主要影响因素.     

Distribution and partition of polycyclic aromatic hydrocarbon in surface water of the Pearl River Estuary, South China

Water samples were collected in the Pearl River Estuary in July 2002 and April 2003. The particulate and dissolved phase polycyclic aromatic hydrocarbons (PAHs) were determined. Total PAH concentrations in water samples were higher in April of 2003 (C (p): 4.0-39.1 ng/L or 445.1-1,089.9 ng/g; C (w): 15.9-184.2 ng/L) than in July of 2002 (C (p): 2.6-26.6 ng/L or 297.7-1,336.6 ng/g; C (w): 12.9-28.3 ng/L). It was found that 5, 6-ring PAHs enrich in the inner estuary samples and so did 3-ring PAHs in the July samples. Compositional differences in the suspended particulate matter (SPM) might be responsible for this observation. The partition coefficient (K (p)) increased with the increasing of the particular organic carbon content of suspended particles as well as the salinity of water, decreased with the increase of the total suspended particles content of samples. A linear correlation between logK (OC) and logK (OW) was found in two sampling periods. The observed values of logK (OC) exceed their predicted values derived form linear free energy relationship between logK (oc) and logK (ow), which could be attributed to the nonlinear sorption of soot-like carbons in suspended particles.     

二(2-乙基己基)磷酸大块液膜中传输四价铈的研究

二(2-乙基己基)磷酸(DEHPA)一直成功的作为一种含有氯仿膜的大块液膜载体有效的传输Ce~(4+)。文章采用有氯仿膜的大块液膜方法进行Ce~(4+)的传输研究,结果表明:pH为2左右的料液中含有纯净的Ce~(4+)或者Ce~(4+)与一些阳离子二者的混合物,这些阳离子包括Ca~(2+),Mg~(2+),Na~+,K~+,Pb~(2+),Fe~(3+),Cu~(2+),以及UO~(2+)等,而0.1mol/L的盐酸为传输池中分散相的反萃取剂。大于99%的Ce~(4+)会在2h以内有选择的渗入液膜以内,而在相同时间内其他阳离子的传输量将少于3%。料液相中存在的Fe~(3+)和UO~(2+)的存在对铈离子的传输有极大的影响。Fe~(3+)可以有效地利用加入到料液中的硫氰化钾或柠檬酸加以掩蔽,但是UO~(2+)的共传输却只能利用加入到料液相中的碳酸盐或硫氰酸盐来加以减少。     

铜、镍、铅、锌4种重金属对水田土壤藻类的综合效应

为确定污水、污泥的农田施用标准,使用正交试验表L₉（3⁴）研究了4种重金属铜、镍、铅和锌在低、中、高3种浓度下对土壤藻类的数量和种类的影响。混合重金属使土壤藻类的种群结构发生改变,使蓝藻数量减少,硅藻数量或减少或增加,视条件而定,裸藻成为优势种。在土壤－藻类体系中重金属临界值铜为50mg/kg,镍为50mg/kg,铅为150mg/kg,锌为300mg/kg。     

土壤重金属污染的调控机理及应用研究

土壤重金属物污染的调控机理和应用研究,是国内外重金属污染土壤修复技术研究的热点和前沿领域。通过利用生物作用、理化措施等调控技术,可降低土壤中重金属的有效态浓度,降低其生物有效性及迁移性。文章阐述了利用植物、微生物、化学改良剂等修复土壤重金属污染的调控机理、影响因素、应用技术等方面的研究现状,讨论了植物修复、微生物作用、固定沉淀、吸附络合、有机络合及螯合、离子拮抗等原理与措施,并提出了其研究应用的发展趋势和展望。     

双叔胺缔合相变-两步反萃法处理萘磺酸系废液

用双步胺缔合相变-两步反革法处理茶磺酸系废液，以自制的2，4-二（N，N-二丁基）氨基十二烷基苯（HG-1）作相变试剂，考察了缔合相变法和两步反萃法的处理效果。实验结果表明：在萘磺酸系废液pH小于等于2的条件下，与三辛胺相比，用HG-1处理萘磺酸系废液可将循环处理次数减少2～3次，循环处理效率提高40%-60%，萃取罐的容积利用率可提高40%。G盐废液、NH2-J酸废液、T酸母液及脱硝废液的COD去除率分别可达99.40%,96.73%,97.77%,99.20%；在氨水加入量为20mL条件下，两步反萃法可从NH2-J酸废液中分出14mL无机盐水相，并可得到7g硫酸铵，分出无机盐水相后的萘磺酸浓缩液体体积比传统的一步反萃法减小了44%。     

活性炭烟气脱硫技术研究新进展

研制了新型活性炭脱硫剂－脱硫活性碳纤维。研究表明，脱硫活性碳纤维由于含碳量高、比表面积大、微孔丰富、孔径分布窄、有较多适于吸附ＳＯ２的表面官能团，因而吸附能力及吸附、脱附速度显著大于普通活性炭。在相同工艺条件下，脱硫活性碳纤维吸附容量为粒状疾性炭的４－５倍，空速粒达活性炭的１０倍。采用活性碳纤维脱硫可比普通活性碳脱硫剂用量成倍减少。另外，由于活性碳纤维阻力小，系统能耗可显著降低。活性碳烟气脱硫采用     

官厅水库周边土壤重金属空间变异特征及风险分析

在官厅水库周边2～10 km范围内系统测定了8种重金属元素的含量,利用GIS技术和地统计分析方法,研究了重金属元素的空间变异特征及环境风险.结果表明,Cd是该区域主要的污染物,检测值（0.68±0.17） mg/kg相当于国家1级标准的3.4倍,40%的区域超过国家2级标准.土壤中7种重金属（Ni除外）的空间变异主要缘自于施肥、耕作及种植制度等人为活动引起的随机性因素,空间格局呈现西高东低,并呈洋河至怀来县区段污染最重的趋势.单因子污染指数和单因子生态危害系数Cd均显著高于其他重金属元素,复合污染指数呈库北高于库南,西部高于东部的空间趋势,复合生态风险指数南北向也有类似分布特征,东西向集中在怀来县、延庆县和中部北辛堡镇3个区域,说明高环境污染区将伴随高的生态风险,人口密集、工业化程度较高的城镇区域更容易引起生态危害.     

我国环境影响评价制度的新近发展

国家新近颁布的《建设项目环境保护管理条例》为主体的一系列管理条例，办法、文件和通知识，导致了我国环境影响评价制度体系的重大改进，标志着我国的环境影响评价制度建设在近期取得重大进展。