Effect of nutrient conditions on the toxicity of naphthalene to Chlorella pyrenoidosa

The toxicity of naphthalene to a freshwater microalga, Chlorella pyrenoidosa, and the subsequent recovery of algae from the damage were investigated under two nutrient conditions, either enriched with nitrogen (N) and phosphorus (P), or starved of N and P. Results showed that C. pyrenoidosa was more sensitive to naphthalene under N,P-enriched condition, and the inhibitory rate generally increased at first and then decreased gradually with the evaporation of naphthalene under both nutrient conditions. Enriched N, P reduced the inhibitory rate at initial naphthalene concentration of 5 and 10 mg/L, but enhanced it at 100 mg/L, at which more severe ultrastructure damages were found than those under N,P-starved condition. Observed damages included partly or totally disappearance of nucleolus, nuclear, and plasma membranes. According to the chlorophyll content and cell density measurements, C. pyrenoidosa could recover from naphthalene damage with initial concentrations 6 50 mg/L in 7 days under both nutrient conditions, while they could not recover if the initial concentration of naphthalene was at 100 mg/L. Under the N,P-starved condition, the inability of C. pyrenoidosa to recover from the naphthalene damage was consistent with the results of high inhibitory rate, low value of specific growth rate (SGR, 0.05 day??1), and the severe destruction of cell structure. However, under the N,P-enriched conditions, the observed lower inhibitory rate, higher value of SGR (0.55 day??1), and the intact cell structure of most cells suggested that algae could potentially recover from the naphthalene damage.     

Mobilities and leachabilities of heavy metals in sludge with humus soil

Chemical forms of Zn, Ni, Cu, and Pb in municipal sewage sludge were investigated by adding humus soil to sludge and by performing sequential extraction procedures. In the final sludge mixtures, Zn and Ni were mainly found in Fe/Mn oxide-bound (F3) and organic matter/sulfide-bound (F4) forms. For Zn, exchangeable (F1), carbonate-bound (F2), and F3 forms were transformed to F4 and residual forms (F5). For Ni, F1 and F2 forms were transformed to F1, F2, and F3 forms. Both Cu and Pb were strongly associated with the stable forms F4 and F5. For Cu, F2 and F3 forms were major contributors, while for Pb, F3 and F4 forms were major contributors to F5. Humus soil dosage and pH conditions in the sludge were strongly correlated with the forms of heavy metals. Five forms were used to evaluate metal mobilities in the initial and final sludge mixtures. The mobilities of the four heavy metals studied decreased after 28 days. The metal mobilities in the final sludge mixtures were ranked in the following order: Ni > Zn > Cu = Pb. Leaching tests showed that the mobilities of Zn and Ni in lower pH conditions (pH 4) were higher than those in higher pH conditions (pH 8).     

Source attributions of heavy metals in rice plant along highway in Eastern China

Air and soil pollution from traffic has been considered as a critical issue to crop production and food safety, however, few efforts have been paid on distinguish the source origin of traffic-related contaminants in rice plant along highway. Therefore, we investigated metals (Pb, Cd, Cr, Zn and Cu) concentrations and stable Pb isotope ratios in rice plants exposed and unexposed to highway traffic pollution in Eastern China in 2008. Significant differences in metals concentrations between the exposed and unexposed plants existed in leaf for Pb, Cd and Zn, in stem only for Zn, and in grain for Pb and Cd. About 46% of Pb and 41% of Cd in the grain were attributed to the foliar uptake from atmosphere, and there were no obvious contribution of atmosphere to the accumulations of Cr, Zn and Cu in grain. Except for Zn, all of the heavy metals in stem were attributed to the root uptake from soil, although significant accumulations of Pb and Cd from atmosphere existed in leaf. This indicated that different processes existed in the subsequent translocation of foliar-absorbed heavy metals between rice organs. The distinct separation of stable Pb isotope ratios among rice grain, leaf, stem, soil and vehicle exhaust further provided evidences on the different pathways of heavy metal accumulation in rice plant. These results suggested that further more attentions should be paid to the atmospheric deposition of heavy metals from traffic emission when plan crop layout for food safety along highway.     

Decolorization of dye solutions with Ruditapes philippinarum conglutination mud and the isolated bacteria

Application of Ruditapes Philippinarum conglutination mud (RPM) for decolorizing synthetic dye solutions was studied. RPM showed good activity for decolorization of Methylene Blue, Crystal Violet, Malachite Green, and Ink Blue. The amount of the RPM had great effect on the decoloration rate of the dye solutions. However, the decoloration rate did not continue to increase when the amount of mud exceeded the optimum dose. The temperature of the dye solution had a remarkable effect on the decolorization rate of Ink Blue solution, but had little effect on the other three dye solutions. The initial pH of the dye solutions evidently affected the decolorization rate of Malachite Green solution, but had less effect on the other three. The decolorization rate of the dye solutions increased significantly with treatment time within 8 hr, but tended to be steady after 8 hr for Methylene Blue, Crystal Violet and Malachite Green solutions, and after 12 hr for Ink Blue solution. The decolorization efficiencies for the four dye solutions under the optimum conditions were all above 90%. Seventeen strains screened from RPM showed flocculation ability for kaolin clay suspension. Out of them, the flocculation rate of strain ZHT3-9 and strain ZHT4-13 were up to 88.14% and 86.01%, respectively. ZHT3-9 was studied, and its decolorization rate for Methylene Blue, Crystal Violet, and Malachite Green reached 90.02%, 89.21%, and 80.29%, respectively. By morphological, physiological and biochemical characteristics analysis and 16S rRNA sequencing, the strain ZHT3-9 was identified as Arthrobacter sp.     

DELtatox便携式毒性测试仪在Q—TOX和B—TOX两种模式下应用与探讨

随着经济社会的发展,突发性水质污染事故日趋增多。因此能够快速、准确测定水质状况是环境应急监测的一项重要工作。在一起水厂取水口有人投药打鱼事故中,采用DELtatox便携式毒性测试仪在Q—TOX和B—TOX两种模式下快速检测事发地水质,结果表明快速、高效的检测为此次污染事故的成功处置提供了技术支持,为以后类似突发污染事故的应急监测提供了参考。     

三丁基锡生殖毒性的研究进展

有机锡化合物,特别是三丁基锡,广泛存在于环境中,对生物体以及生态环境存在着潜在的威胁。本文综述了三丁基锡对软体动物、鱼类和哺乳动物生殖机能的影响及其其可能的作用机制,指出了进一步的研究方向。     

PAS-PDMDAAC复合混凝剂研究

以Al2（SO）4和PDMDAAC为原料进行了无机-有机复合絮凝剂的复合实验研制,确定其制备工艺条件,并对油田现场采集的钻井废水作絮凝沉降实验,所研制的PAS-PDMDAAC复合絮凝剂对COD的去除效率可大大提高.     

Ultrasonic preparation of nano-nickel/activated carbon composite using spent electroless nickel plating bath and application in degradation of 2,6-dichlorophenol

Ni was effectively recovered from spent electroless nickel （EN） plating baths by forming a nano-nickel coated activated carbon composite. With the aid of ultrasonication, melamine- formaldehyde-tetraoxalyl-ethylenediamine chelating resins were grafted on activated carbon （MFT/AG）. PdC12 sol was adsorbed on MFT/AC, which was then immersed in spent electroless nickel plating bath; then nano-nickel could be reduced by ascorbic acid to form a nano-nickel coating on the activated carbon composite （Ni/AC） in situ. The materials present were carefully examined by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy and electro- chemistry techniques. The resins were well distributed on the inside and outside surfaces of activated carbon with a size of 120 ± 30 nm in MFT/AC, and a great deal of nano-nickel particles were evenly deposited with a size of 3.8 ± 1.1 nm in Ni/MFT. Moreover, Ni/AC was successfully used as a catalyst for ultrasonic degradation of 2.6-dichloronhenol.     

南京市氮氧化物排放行业分布特征及减排对策

采用污染源普查资料与实地调查相结合的方法,对南京市各行业氮氧化物(NOx)排放源及排放量进行调查和梳理。结果表明:各行业NO x排放分担率依次为电力41%、机动车25%、钢铁10%、水泥9%、石化7%、其它工业5%、居民生活3%。针对南京市现状,对重点排放源提出了NO x减排措施与对策。     

饮用水源地的水华对人体健康风险评价

饮用水源地的水华现象近年来在世界各地不断爆发,给人类饮水安全造成极大的威胁。本文通过检测微囊藻毒素和三卤甲烷类物质,利用急性暴露安全阈值（浓度）计算模型,计算出了各自的急性暴露安全阅值,并对健康风险进行了评价。