Investigating the sources of the mutagenic activity found in a river using the Salmonella assay and different water extraction procedures

In the routine São Paulo state (Brazil) surface water quality-monitoring program, which includes the Salmonella microsome mutagenicity assay as one of its parameters, a river where water is taken and treated for drinking water purposes has repeatedly shown mutagenic activity. A textile dyeing facility employing azo-type dyes was the only identifiable source of mutagenic compounds. We extracted the river and drinking water samples with XAD4 at neutral and acidic pH and with blue rayon, which selectively adsorbs polycyclic compounds. We tested the industrial effluent, raw, and treated water and sediment samples with YG1041 and YG1042 and compared the results with the TA98 and TA100 strains. The elevated mutagenicity detected with YG-strains suggested that nitroaromatics and/or aromatic amines were causing the mutagenicity detected in the samples analyzed. Positive responses for the blue rayon extracts indicated that mutagenic polycyclic compounds were present in the water samples analyzed. The mutagen or mixture of mutagens present in the effluent and water samples cause mainly frameshift mutations and are positive with and without metabolic activation. The Salmonella assay combined with different extraction procedures proved to be very useful in the identification of the origin of the pollution and in the identification of the classes of chemical compounds causing the mutagenic activity in the river analyzed.     

Protective role of isoflavones against the toxic effect of cypermethrin on semen quality and testosterone levels of rabbits

Cypermethrin is considered as one of the endocrine disruptors. Isoflavones play an important role in various physiological processes in the body. It has both estrogenic and antioxidant effects. The objective of this study was to evaluate the protective role of isoflavones (2 mg/kg B.W) on semen quality and plasma testosterone levels of male New Zealand White rabbits given sublethal dose (24 mg/kg BW every other day for 12 weeks) of cypermethrin. Results showed that treatment with cypermethrin caused a significant decreases (P < 0.05) in ejaculate volume, sperm concentration, total sperm output, sperm motility (%), total motile sperm per ejaculate (TMS), packed sperm volume (PSV), semen initial fructose and plasma testosterone. In addition, live body weight (LBW), dry matter intake (DMI) and relative weights of testes and epididymis were decreased. On the other hand, treatment with cypermethrin increased (P < 0.05) the numbers of abnormal and dead sperms, and initial hydrogen ion concentration (pH). Results indicated that the presence of isoflavones together with cypermethrin was capable to minimize its harmful effects. Treatment with isoflavones alone had positive effects on some semen characteristics in spite of it is considered as estrogen-like compound. Since it causes significant increases in libido (by decreasing the reaction time), PSV, sperm motility and TMS, while abnormal and dead sperm were reduced compared to control animals. Meanwhile, isoflavones had no negative effect on ejaculate volume, total sperm output, sperm concentration, initial fructose concentration, pH and plasma testosterone levels. Results demonstrated the beneficial influences of isoflavones in reducing the negative effects of cypermethrin on reproductive characteristics of mature male rabbits. Interestingly, data showed that isoflavones alone caused an improvement in some semen quality and had no negative effects on male fertility, and did not have negative effects on male fertility.     

德尔菲法在归纳主要环境问题中的应用

尝试用德尔菲法归纳建德市的主要环境问题,对15位专家的2轮咨询结果进行统计分析,筛选出15个指标组合成10个主要环境问题,较好地反映了建德市的环境污染现状和变化趋势。     

北京市乡镇污水处理厂的运行管理机制

"十一五"期间,北京市不断加大农村基础建设的投资力度,乡镇污水处理厂建设资金问题基本可以落实,但是管理模式、运行费用问题仍有待进一步解决. 我国乡镇污水处理设施建设远远滞后于经济的发展,然而随着国家对农村建设投入的不断加大,乡镇污水处理设施也将不断完善."十一五"期间,北京市不断加大农村基础建设的投资力度,乡镇污水处理厂建设资金问题基本可以落实,但是管理模式、运行费用问题仍有待进一步解决.     

Bioavailability of metals along a contamination gradient in San Diego Bay (California, USA)

San Diego Bay is heavily contaminated with metals, but little is known about their biological availability to local marine organisms. This study on 15 elements showed that concentrations of metals associated with sediment increased from the mouth to the back of the Bay while metals in seawater particulates were similar throughout the Bay. Metal bioavailability was assessed over 8weeks following transplant of the local brittlestar, Ophiothrix spiculata (Ophuroidea, Echinodermata), from outside to inside the Bay. Despite a gradient of contamination, brittlestars accumulated similar levels of metals throughout the Bay, suggesting that metal contamination occurred through dissolved metals as well as through the diet. Sediment transplanted in dialysis tubing in the Bay accumulated metals only when placed on the seafloor bottom, indicating greater metal bioavailability near the bottom; the level of accumulation was similar between the mouth and the back of the Bay. The results are consistent with a circulation pattern in which a bottom layer of seawater, enriched with metals, drains from the back to the mouth of the Bay. There was a positive correlation between metal concentration in brittlestars and tidal range, suggesting increased metal exposure due to bay-ocean water exchange. For brittlestar arms the correlation was higher at the mouth than the back of the Bay, indicating greater metal accumulation in arms from dissolved metals in seawater than from ingestion of metal contaminated diet. In contrast, for brittlestar disks the correlation was higher at the back of the Bay, indicative of metal accumulation mainly through the diet. The results highlight the importance of considering bioavailability and physical processes in environmental quality assessments.     

Accumulation of weathered polycyclic aromatic hydrocarbons (PAHs) by plant and earthworm species

Experiments were conducted to assess the bioavailability of polyclycic aromatic hydrocarbons (PAHs) in soil from a Manufactured Gas Plant site. Three plant species were cultivated for four consecutive growing cycles (28 days each) in soil contaminated with 36.3 microg/g total PAH. During the first growth period, Cucurbita pepo ssp. pepo (zucchini) tissues contained significantly greater quantities of PAHs than did Cucumis sativus (cucumber) and Cucurbita pepo ssp. ovifera (squash). During the first growth cycle, zucchini plants accumulated up to 5.47 times more total PAH than did the other plants, including up to three orders of magnitude greater levels of the six ring PAHs. Over growth cycles 2-4, PAH accumulation by zucchini decreased by 85%, whereas the uptake of the contaminants by cucumber and squash remained relatively constant. Over all four growth cycles, the removal of PAHs by zucchini was still twice that of the other species. Two earthworm species accumulated significantly different amounts of PAH from the soil; Eisenia foetida and Lumbricus terrestris contained 0.204 and 0.084 microg/g total PAH, respectively, but neither species accumulated measurable quantities 5 or 6 ring PAHs. Lastly, in abiotic desorption experiments with an aqueous phase of synthetically prepared organic acid solutions, the release of 3 and 4 ring PAHs from soil was unaffected by the treatments but the desorption of 5-6 ring constituents was increased by up to two orders of magnitude. The data show that not only is the accumulation of weathered PAHs species-specific but also that the bioavailability of individual PAH constituents is highly variable.     

Dioxin and dioxin-like PCB exposure of non-breastfed Dutch infants

The exposure of humans to PCDD/Fs (polychlorinated dibenzo-p-dioxins and dibenzofurans) and dioxin-like PCBs (dl-PCBs, i.e. polychlorinated non-ortho and mono-ortho biphenyls) occurs predominantly via the intake of food. Young children have a relatively high intake of these substances, due to their high food consumption per kilogram body weight. As the exposure of non-breastfed infants to these compounds has not been assessed before in The Netherlands, we studied the dietary intake of 17 PCDD/Fs and 11 dioxin-like PCBs in 188 Dutch non-breastfed infants between 4 and 13 months. The food intake of the infants was assessed by a 2-d food record. From these data PCDD/F and dioxin-like PCB intake was calculated using PCDD/F and dioxin-like PCB concentrations of food products sampled in 1998/1999 in The Netherlands. The long-term PCDD/F and dioxin-like PCB exposure of the infants was calculated using the statistical exposure model (STEM). For infants of 5 months the chronic exposure to PCDD/F and dioxin-like PCB was 1.1pg WHO-TEQ (toxic equivalents) per kilogram body weight (bw) per day (95th percentile: 1.7pg WHO-TEQ/kg bwxd), which mainly originated from infant formula and vegetables and increased to 2.3pg WHO-TEQ/kg bwxd (95th percentile 3.7pg WHO-TEQ/kg bwxd) for infants just over 1 year old eating the same food as their parents. The percentage of formula-fed infants with an exposure exceeding the TDI of 2pg WHO-TEQ/kg bwxd was 5% at 5 months, 49% at 9 months and 64% at 12 months.     

Soil-dependent uptake of 137Cs by mushrooms: experimental study in the Chernobyl accident areas

The influence of agrochemical properties of forest soils and growth conditions on 137Cs aggregated transfer factors from soil to different species of forest mushrooms have been analysed. Statistically significant correlations between 137Cs soil to mushroom aggregated transfer factors and agrochemical soil properties have been revealed. The experimental data show that 137Cs aggregated transfer factors depend on the mushroom's trophic group, biological family, genus and species. They also strongly depend on forest soil properties and their values can be estimated with the use of multiple regression equations constructed from agrochemical soil parameters which most closely correlate with the 137Cs transfer parameters for particular mushroom groups.     

Copper fractionation with dissolved organic matter in natural waters and wastewater--a mixed micelle mediated methodology (cloud point extraction) employing flame atomic absorption spectrometry

A cloud point extraction-preconcentration methodology for the speciation analysis of free and organically complexed metal species in natural waters is presented. The method is based on the neutralization of the electrostatic charge of the humate-metal complexes with a positively charged surfactant in a high ionic strength solution environment. The resulting complexes are conveniently solubilized in the micelles of a non-ionic surfactant medium and are thus separated from the bulk aqueous phase. Free metal species are also determined by complexation with a conventional chelating agent under mild conditions. The overall procedure is easy, rapid and allows for a high sample throughput in terms of massive analysis of many samples in the same time period. The method offers substantially low detection limits of 8.5 and 0.9 micrograms l-1 for bound and labile species respectively, with a calibration curve rectilinear in the wide range 40-150 micrograms l-1 for the humate associated and 4-40 micrograms l-1 for the free metal species. The method is free from interferences yielding recoveries in the range 97-102% for various samples of different matrixes.     

氮氧化物分析仪不同测量量程比较

对氮氧化物分析仪在不同测量量程范围内采集室外环境空气分析的结果进行了讨论和统计检验，得出分析仪在不同测量量程范围采集室外环境空气分析的结果基本一致，它们之间具有高度的一致性、相关性及可比性。