陆浑水库沉积物重金属空间分布特征及风险评价

为了解洛阳市饮用水水源地陆浑水库沉积物中重金属污染程度,采集32个点位的表层沉积物,分析6种重金属（Cd、Cr、Cu、Ni、Pb和Zn）的空间分布特征,并运用地累积指数法、潜在生态风险指数和聚类分析等方法对研究区重金属污染程度进行评价、生态风险评价及源解析.结果表明：Cd、Cu、Pb和Zn含量超过黄河流域河南段重金属土壤背景值,分别是其8.8、2.0、6.5、2.3倍,重金属存在明显富集,且主要污染集中于坝前区域.地累积指数法评价结果显示,Cd为强污染,Pb为中-强污染.潜在生态风险指数表明,陆浑水库沉积物重金属风险呈自上游至下游逐渐增强的趋势,总体处于高度生态危害,潜在生态风险指数均值达到312.94,其中Cd为主要贡献因子.富集系数法和聚类分析结果显示：Cd、Cu、Pb和Zn主要为人为源,Cr和Pb以自然源为主.总体而言,陆浑水库沉积物中重金属Cd和Pb污染相对较重,可能会对水库水环境构成威胁.     

Application of compost in agricultural practice could potentially cause contamination of foodstuffs with pathogenic bacteria such as Escherichia coli O157:H7. This study investigated pathogenic bacteria in compost collected from the compost facilities, an

IntroductionIncreasing public interests have been concerned onsafety foods and the environmental aspects recently,especially on the so-called organic foods , which are madefromcrops grown with organic fertilizers or compost but notchemical fertilizers .Pu…     

Potential bioremediation of mercury-contaminated substrate using filamentous fungi isolated from forest soil

The use of filamentous fungi in bioremediation of heavy metal contamination has been developed recently. This research aims to observe the capability of filamentous fungi isolated from forest soil for bioremediation of mercury contamination in a substrate. Six fungal strains were selected based on their capability to grow in 25 mg/L Hg2+-contaminated potato dextrose agar plates. Fungal strain KRP1 showed the highest ratio of growth diameter, 0.831, thus was chosen for further observation.Identification based on colony and cell morphology carried out by 18S rRNA analysis gave a 98%match to Aspergillus flavus strain KRP1. The fungal characteristics in mercury(Ⅱ) contamination such as range of optimum pH, optimum temperature and tolerance level were 5.5–7 and 25–35℃ and 100 mg/L respectively. The concentration of mercury in the media affected fungal growth during lag phases. The capability of the fungal strain to remove the mercury(Ⅱ) contaminant was evaluated in 100 mL sterile 10 mg/L Hg2+-contaminated potato dextrose broth media in 250 mL Erlenmeyer flasks inoculated with 108spore/mL fungal spore suspension and incubation at 30℃ for 7 days. The mercury(Ⅱ) utilization was observed for flasks shaken in a 130 r/min orbital shaker(shaken) and nonshaken flasks(static) treatments. Flasks containing contaminated media with no fungal spores were also provided as control. All treatments were done in triplicate. The strain was able to remove 97.50%and 98.73% mercury from shaken and static systems respectively. A. flavus strain KRP1 seems to have potential use in bioremediation of aqueous substrates containing mercury(Ⅱ) through a biosorption mechanism.     

汞分析仪直接测定土壤中总汞的方法研究

建立了利用RP91C-RA915M汞分析仪直接测定土壤中总汞的方法。该方法直接固体进样,省去了常规方法加酸消解、赶酸、定容等繁琐的前处理步骤;利用标准土壤绘制工作曲线,无需反复稀释标准储备液配制标准溶液,测定了方法检出限、精密度及准确度。结果表明此方法准确、可靠,是一个比较理想的分析方法。本方法的检出限为0.25μg/kg,相对标准偏差为1.98%~4.92%,标准样品测定准确,加标回收率为92.8%~106%。     

CIELAB color variables as indicators of compost stability

The composting process of different organic wastes both in laboratory and on a large-scale was characterized using CIELAB color variables to evaluate compost stability for the better application in agriculture. The time courses of the CIELAB variables of composting materials were determined directly from the bottom of a glass petri dish filled with dried and ground samples using a Minolta Color Reader (CR-13) calibrated with clean empty petri dishes placed on a white tile. To compare the proposed method with conventional methods, the same materials were also evaluated using commonly used compost stability evaluation indices. Most of the CIELAB variables of a compost made from a mixture of green tea waste and rice bran reached a plateau after 84 days of composting and showed strong relationships with the commonly used compost stability evaluation indices. The time needed for CIELAB variables, especially the L*and b* values, to stabilize at large-scale composting plants of cattle litter, farmyard manure, kitchen garbage and bark compost, were more or less similar to the times of maturation evaluated by the respective compost producers. The CIELAB color variable offers a new, simple, rapid and inexpensive means of evaluating compost stability and its quality prior to agricultural use.     

Detection of dicofol and related pesticides in human breast milk from China, Korea and Japan

Previously, we demonstrated that the concentrations of DDTs were greater in breast milk collected from Chinese mothers than from Japanese and Korean mothers. To investigate dicofol as a possible source of the DDTs in human breast milk, we collected breast milk samples from 2007 to 2009 in China (Beijing), Korea (Seoul, Busan) and Japan (Sendai, Takarazuka and Takayama). Using these breast milk samples, we quantified the concentrations of dichlorobenzophenone, a pyrolysis product of dicofol (simply referred to as dicofol hereafter), dichlorodiphenyltrichloroethane and its metabolites (DDTs) using GC-MS. Overall, 12 of 14 pooled breast milk samples from 210 mothers contained detectable levels of dicofol (>0.1 ng g⁻¹ lipid). The geometric mean concentration of dicofol in the Japanese breast milk samples was 0.3 ng g⁻¹ lipid and significantly lower than that in Chinese (9.6 ng g⁻¹ lipid) or Korean breast milk samples (1.9 ng g⁻¹ lipid) (p < 0.05 for each). Furthermore, the ΣDDT levels in breast milk from China were 10-fold higher than those from Korea and Japan. The present results strongly suggest the presence of extensive emission sources of both dicofol and DDTs in China. However, exposure to dicofol cannot explain the large exposure of Chinese mothers to DDTs because of the trace levels of dicofol in the ΣDDTs. In the present study, dicofol was confirmed to be detectable in human breast milk. This is the first report to identify dicofol in human samples.     

Quantitative analysis of perfluorinated chemicals in media for in vitro fertilization and related samples

The actual standard in vitro fertilization (IVF) protocol recommends an overnight gamete co-incubation. All of the culture media used for human IVF are supplemented with serum or albumin. In the present study, we determined the concentrations of perfluorinated chemicals (PFCs) in IVF media (IVFM) and related samples by liquid chromatography with tandem mass spectrometry (LC/MS/MS). The results indicated that the concentrations of PFOS and PFOA in the protein source were higher than those in the IVFM samples. Compared with human plasma concentrations of PFCs, PFCs in all of the IVFM samples, such as PFBS, PFHxS and PFOA, were either not detected or present at only trace levels, even when protein source was added. LC/MS/MS could be used to determine PFCs in IVFM samples in future studies of the effects of PFC exposure on intrauterine insemination.     

Separation of plastic mixtures using liquid-fluidized bed technology

Separation of heavier-than-water plastic mixtures had been investigated via the fluidization of their packed beds induced by an upward flow of water. The samples examined were resin pellets and crushed plastic products including PVC, PET and PBT. On the onset of a flow, a mixed bed was swelled to the state of fluidization and separated into layers of respective resins depending on their density. The effects of the flow rate, an amount of the samples and their density difference were examined on the separation of resin pellets. Under an appropriate condition, the process was completed within a few minutes, and satisfactory separation was attained when the density difference of the samples exceeded 0.05 g cm-3. By using a column equipped with several sample outlets sorted resins could be recovered with their purity intact by withdrawing each layer successively from above through a suitable outlet. Multi-stage separation was also found to be effective in treating close-density samples. Compared with uniform-sized resin pellets, size distribution of crushed plastic samples deteriorated the separation to some extent.     

二氧化氯消毒前后污水毒性的变化及消毒条件的影响

采用发光细菌试验和umu试验,分别考察了二氧化氯投加量和反应时间对污水二氧化氯消毒后急性毒性和遗传毒性变化的影响.结果表明,随着二氧化氯消毒剂投加量的增加,消毒后水样的急性毒性不断增大,但遗传毒性逐渐减小后趋于稳定.随着反应时间的延长,二氧化氯的消耗量不断增大,消毒后水样的急性毒性先增大后减小,遗传毒性逐渐减小后趋于稳定.由于消毒条件对污水急性毒性和遗传毒性有着不同的影响,说明污水中产生急性毒性和产生遗传毒性的物质不同,对于某一种污水,通过控制消毒条件可以使消毒后污水的急性毒性和遗传毒性都较低.