Microcystin accumulation and biochemical responses in the edible clam Corbiculaleana P. exposed to cyanobacterial crude extract

We investigated the accumulation and effects of cyanobacterial crude extract(CCE)containing microcystins(MCs) on the edible clam Corbicula leana P. Toxic effects were evaluated through the activity of antioxidant and detoxification enzymes: catalase(CAT),superoxide dismutase(SOD), and glutathione-S-transferases(GSTs) from gills, foot, mantle and remaining soft tissues. Clams were exposed to CCE containing 400 μg MC-LReq/L for10 days and were then kept in toxin-free water for 5 days. Clam accumulated MCs(up to 3.41 ± 0.63 μg/g dry weight(DW) of unbound MC and 0.31 ± 0.013 μg/g DW of covalently bound MC). Detoxification and antioxidant enzymes in different organs responded differently to CCE during the experiment. The activity of SOD, CAT, and GST in the gills and mantle increased in MC-treated clams. In contrast, CAT and GST activity was significantly inhibited in the foot and mostly only slightly changed in the remaining tissues. The responses of biotransformation, antioxidant enzyme activity to CCE and the fast elimination of MCs during depuration help to explain how the clam can survive for long periods(over a week) during the decay of toxic cyanobacterial blooms in nature.     

天津市宝坻区农村地下水健康风险评价

通过对天津市宝坻区农村地下水水体中NH3-N,F,Hg,Pb,As和Cr6+浓度进行调查研究,应用美国环保局(EPA)推荐的健康风险评价模型对农村地下水水体中污染物引起的健康风险进行评价。结果表明,宝坻区农村,As通过饮水途径引起的致癌风险最大(1.8 10-5 a-1),通过饮水途径引起非致癌健康风险中F最大,NH3-N次之;致癌物质通过饮水途径所致健康风险远大于非致癌物质,但二者都低于国际防辐射委员会(ICRP)的推荐标准。     

植物修复在水环境生态修复中的应用

介绍了平原河网水资源现状及问题成因,对植物修复在水环境生态修复中的应用作了详细的论述,分析了其存在的问题,展望了植物修复应用的发展方向。     

Adsorption of humic acid from aqueous solution on bilayer hexadecyltrimethyl ammonium bromide-modified zeolite

Surfactant-modified natural zeolites (SMNZ) with different coverage types were prepared by loading hexadecyltrimethyl ammonium bromide (HTAB) onto the surface of a natural zeolite. The adsorption behavior of humic acid (HA) on SMNZ was investigated. Results indicate that the adsorbent SMNZ exhibited a higher affinity toward HA than the natural zeolite. HA removal efficiency by SMNZ increased with HTAB loading. Coexisting Ca²⁺ in solution favored HA adsorption onto SMNZ. Adsorption capacity decreased with an increasing solution pH. For typical SMNZ with bilayer HTAB coverage, HA adsorption process is well described by a pseudo-second-order kinetic model. The experimental isotherm data fitted well with the Langmuir model. Calculated maximum HA adsorption capacities for SMNZ with bilayer HTAB coverage at pH 5.5 and 7.5 were 63 and 41 mg·g⁻¹, respectively. E2/E3 (absorbance at 250 nm to that at 365 nm) and E4/E6 (absorbance at 465 nm to that at 665 nm) ratios of the residual HA in solution were lower than that of the original HA solution. This indicates that the HA fractions with high polar functional groups, low molecular weight (MW), and aromaticity had a stronger tendency for adsorption onto SMNZ with bilayer HTAB coverage. Results show that HTAB-modified natural zeolite is a promising adsorbent for removal of HA from aqueous solution.     

大型溞对氰法、锑冶炼碱渣的毒性评价

采用大型溞为试验生物对氰渣、锑冶炼碱渣进行毒性试验研究.结果表明,氰渣、锑冶炼碱渣能够抑制大型溞的运动,并造成溞的大量死亡.所测得的半数运动受抑制浓度EC_(50)值,氰渣24h为7.5％,48h及96h分别为0.24％,锑冶炼碱渣96hEC_(50)值为98％.所测得的半数致死浓度LC_(50)值,48及96h分别为0.43％及0.19％.     

PACS絮凝剂的制备及其性能研究

以Al(OH)_3,HCl,H_2SO_4和Na_2CO_3为原料制备含SO_4~(2-)的聚合氯化铝(简称PACS),试验了它的性能及影响因素。结果表明:SO_4~(2-)含量、碱化度和pH影响PACS的絮凝效果,当Al~(3+)/SO_4~(2-)(摩尔比)=15—17时絮凝效果最佳。实验还表明PACS较PAC的絮凝效果要好。     

松花江水系有机污染的现状

本文介绍了GC、GC/MS、HPLC方法在分析松花江水系有机污染物中的应用。GC/MS、HPLC所用水样在现场处理,而TLC、GC样品在实验室处理。冬夏两次取样,共检出152种有机化合物,其中主要有机污染物55种,PAH_3占19％,氯化物占14％,芳烃占13％,其它占54％。     

水生植物对面源污水净化效率研究

于自然条件下研究了慈茹、菱白等7种水生植物对面源污水的净化率。结果表明,7种试验植物对水体中N、P均有很高的净化率,其中以慈茹和菱白的综合净化率为最高。由于不同植物对N、P的净化率不同,所以多种植物配置可提高植物对面源污水的综合净化率。     

污灌对蔬菜的生理生态指标及细胞学影响研究

对污灌蔬菜的生态生理指标及细胞学影响的差异进行研究的结果表明,污灌菠菜的叶绿素含量和相对电导率分别是非污灌菠菜的85.30％和161％。污灌菠菜的硝酸盐含量比非污灌菠菜高出10％,污灌大蒜等不正常有丝分裂为11.3％,而非污灌大蒜为0     

序列间歇式活性污泥法处理毛纺厂废水的研究

采用序列间歇式活性污泥法处理毛纺厂废水。试验结果表明,经4h曝气处理,进水COD为190～650mg/L时,出水COD始终低于100mg/L,去除率大多在80％～90％之间,色度去除率大多在50％以上,出水COD和色度均达到行业排放标准。还对较低COD浓度下序列间歇式活性污泥法的COD降解过程进行了研究,推导出一级反应动力学关系式Sr＝So（1－10￣^-k1^t）,并以试验数据进行了拟合,求解出动力学常数k1和So。