2种典型碳纳米管低浓度暴露诱发锦鲫组织损伤与肝脏氧化损伤效应研究

采用半静态染毒方法,研究了单壁碳纳米管（SWCNT）和羟基化多壁碳纳米管（MCWNT-OH）对锦鲫抗氧化防御系统的影响。 结果表明,锦鲫经28d不同质量浓度的SWCNT和MWCNT-OH（0,10,100和1000μg/L）暴露后,暴露组14d鳃组织切片检查发现出现鳃动脉瘤、鳃细胞水肿、畸形生长等病理症状;然而在2种碳纳米管低浓度暴露下,锦鲫的肝脏切片没有观察到损伤,高浓度时肝脏有轻微空泡损伤。暴露期间锦鲫没有死亡,随着暴露天数的增加,2种碳纳米管都能对SOD和CAT酶产生抑制作用,高浓度组抑制明显,肝脏抗氧化系统受到损伤。指出,虽然碳纳米管的毒性较低,但其长期暴露对鱼类的影响仍需进一步关注。     

氯仿,四氯化碳对蚕豆根尖细胞微核诱发效应的比较研究

利用蚕豆根尖细胞微核方法检测氯仿、四氯化碳的诱变效应,结果表明,氯仿从０．０１ｇ／Ｌ至１．０各浓度组微核率明显高于阴性对照组（Ｐ〈０．０１）,亦高于阳性对照组（Ｐ〈０．０１）,四氯化碳从０．０１ｇ／Ｌ至１．０ｇ／Ｌ各浓度组微核率同样明显高于阴性及阳性对照组（Ｐ〈０．０１）,且同一浓度的２种药物诱发微核率比较,氯仿高于四氯化碳,差异非常显著,说明氯仿的诱变活性强于四氯化碳。     

鱼血微核试验评价长江江苏段水污染遗传毒性

采用原位监测野生鲫鱼外周血红细胞的微核发生率评价长江江苏段水污染的遗传毒性,并与实验室内的Cr(Ⅵ)诱变试验结果进行对比分析。结果表明,常熟望虞河口、江阴滨江村调查点的水污染对鲫鱼的遗传毒性最高,海门江心沙农场其次,江浦、江宁、靖江、镇江调查点的毒性最低。     

用紫露草微核技术监测污水初探

紫露草微核监测不同于理化监测,它反映的是环境污染中诱度因子对生物细胞遗传物质DNA的作用强度。微核率的大小反映出污染物对生物体影响程度的大小,本文初探该法用于污水监测。     

电磁辐射环境的潜在致突变水平

通过蚕豆根尖细胞微核试验,对微波通信基站和广播电台周围环境电磁辐射水平进行监测,了解了不同电磁辐射强度与蚕豆根尖细胞微核率之间的关系。指出较强电磁辐射水平对蚕豆根尖微核率的形成具有显著影响,电磁辐射环境可能存在潜在的致突变危险。建议国家有关部门应尽快对有关场所中的电磁辐射环境,以及对公众健康影响的问题作深入研究,制定可操作性法规,并明确界定有关场所可执行的标准,使建筑物高层电磁辐射环境污染得到有效地控制和管理。     

不同暴露时间下Zn~(2+)和Cd~(2+)对萼花臂尾轮虫种群增长的毒性影响

采用群体累积培养方法,考察不同亚致死浓度水平的Zn~(2+)、Cd~(2+)和Zn~(2+)-Cd~(2+)在不同暴露时间下对萼花臂尾轮虫3 d种群增长率的影响。结果表明,随着暴露时间的延长,各处理组对轮虫种群增长的抑制作用在增加。Zn~(2+)-Cd~(2+)在中、低浓度处理组及短的暴露时间条件下表现为拮抗效应,而在高浓度处理组中表现为协同效应,且随着暴露时间的增加,协同作用效应在增加。     

上海市雾霾污染物对人群健康影响的统计研究

通过收集2013—2015年上海市每日雾霾污染物浓度数据、气象监测数据,并统计研究期间就诊于上海市某医院的门急诊量数据,分析PM_(2.5)浓度与门急诊量的暴露-反应关系,进而研究PM_(2.5)对人群健康的影响。采用泊松分布的半参数广义相加模型,以医院每日门急诊量为响应变量,通过样条平滑函数控制长期趋势、季节趋势、星期效应和气象因素等混杂因素,拟合PM_(2.5)浓度与每日门急诊量的暴露-反应关系模型。结果表明,PM_(2.5)浓度升高会引起医院呼吸内科、心血管内科和皮肤科门急诊量的增加。     

以MnSO4作催化剂快速测定水中COD

建立了酸性条件下,以MnSO4代替Ag2SO4作催化剂快速测定水中COD的方法.考察了K2Cr2O7用量、MnSO4用量、H2SO4浓度、消解温度、消解时间等因素的影响,确定了最佳试验条件和最佳测定范围.方法精密度和准确度均能满足测定要求,与重铬酸钾法作对比试验,测定结果基本一致.     

蒸发浓缩法在地面水COD测定中可行性研究

本文对蒸发浓缩法用于地面水中低浓度ＣＯＤ的测定作了研究,实验结果表明,地面水中ＣＯＤ物质在碱性条件下,能得以定量浓缩,然后采用重铬酸钾法进行测定,所得结果的精密度和准确度良好,若通过蒸发浓缩处理使ＣＯＤ物质浓缩５倍,则可使重铬酸钾法的最低检测限浓度由５０ｍｇ／Ｌ降低到１０ｍｇ／Ｌ,从而使该方法能够适用于地面水水质标准中各类水质ＣＯＤ检测要求。     

大型蚤急性毒性试验的质量控制

为加强大型蚤急性毒性试验的质量控制,采用重铬酸钾作为参考毒物分析了不同日龄母蚤所产幼蚤的毒性效应变化。研究发现,在大型蚤急性毒性试验中,对于在11~56日龄期间的母蚤,以35日龄母蚤所产幼蚤对重铬酸钾的敏感度最高,47日龄母蚤所产幼蚤的敏感度最低。在一定范围内,提高稀释水硬度可显著降低大型蚤对重铬酸钾的敏感度。重铬酸钾的24h-EC ₅₀值的实验室精密度以29~42日龄母蚤组所产幼蚤最好,其次为15~28日龄母蚤组;经t检验,大于42日龄母蚤组所产幼蚤对重铬酸钾24h-EC ₅₀值与15~28日龄母蚤组有显著性差异(P＜0.05),与29~42日龄母蚤组有高度显著性差异(P＜0.01),表明以20℃为大型蚤培养温度时,大型蚤毒性试验宜选用15~42天母蚤所产幼蚤。进行大型蚤急性毒性试验时,应定期使用参考毒物检查毒性试验的实验精密度并运用质量控制图来验证持续的实验室能力。     

Genotoxic effects of water pollution on two fish species living in Karasu River,Erzurum, Turkey

Karasu River, which is the only river in the Erzurum plain, is the source of the Euphrates River (Eastern Anatolia of Turkey). The river is in a serious environmental situation as a result of pollution by agricultural and industrial sewage and domestic discharges. The present study aims to evaluate genotoxic effects of toxic metals in chub, Leuciscus cephalus, and transcaucasian barb, Capoeta capoeta, collected from contaminated site of the Karasu River, in comparison with fish from an unpolluted reference site. Heavy metal concentrations in surface water of the river were determined. The condition factor (CF) was taken as a general biomarker of the health of the fish, and genotoxicity assays such as micronucleus (MN) and other nuclear abnormalities (NA) were carried out on the fish species studied. MN and NA such as kidney-shaped nucleus, notched nucleus, binucleated, lobed nucleus, and blebbed nucleus were assessed in peripheral blood erythrocytes, gill epithelial cells, and liver cells of the fish. A significant decrease in CF values associated with a significant elevation in MN and NA frequencies was observed in fish collected from the polluted sites compared with those from the reference site. Results of the current study show the significance of integrating a set of biomarkers to identify the effects of anthropogenic pollution. High concentrations of heavy metals have a potential genotoxic effects, and the toxicity is possibly related to industrial, agricultural, and domestic activities.     

Genotoxicity assessment of soils from wastewater irrigation areas and bioremediation sites using the Vicia faba root tip micronucleus assay

Genotoxicity potential of soils taken from wastewater irrigation areas and bioremediation sites was assessed using the Vicia faba root tip micronucleus assay. Twenty five soils were tested, of which 8 were uncontaminated soils and taken as the control to examine the influence of soil properties; 6 soils were obtained from paddy rice fields with a history of long-term wastewater irrigation; 6 soils were obtained from bioremediation sites to examine effects of bioremediation; and 5 PAH-contaminated soils were used to examine methodological effects between direct soil exposure and exposure to aqueous soil extracts on micronuclei (MN) frequency ( per thousand) in the V. faba root tips. Results indicate that soil properties had no significant influences on MN frequencies (p > 0.05) when soil pH varied between 3.4 to 7.6 and organic carbon between 0.4% and 18.6%. The MN frequency measured in these control soils ranged from 1.6 per thousand to 5.8 per thousand. MN frequencies in soils from wastewater irrigation areas showed 2- to 48-fold increase as compared with the control. Soils from bioremediation sites showed a mixed picture: MN frequencies in some soils decreased after bioremediation, possibly due to detoxification; whereas in other cases remediated soils induced higher MN frequencies, suggesting that genotoxic substances might be produced during bioremediation. Exposure to aqueous soil extracts gave a higher MN frequency than direct exposure in 3 soils. However, the opposite was observed in the other two soils, suggesting that both exposure routes should be tested in case of negative results from one route. Data obtained from this study indicate that the MN assay is a sensitive assay suitable for evaluating genotoxicity of soils.     

Habitat monitoring and genotoxicity in Ucides cordatus (Crustacea: Ucididae), as tools to manage a mangrove reserve in southeastern Brazil

In Brazil, the state of São Paulo contains both preserved areas (Juréia-Itatins Ecological Station) and extremely impacted ones (Cubatão Municipality). This study evaluated the concentrations of five metals (Cu, Cd, Cr, Pb, and Hg) in two mangroves with different levels of anthropogenic impact and the apparent genotoxicity to Ucides cordatus. Water and sediment samples were obtained, and metal concentrations were determined with an atomic absorption spectrophotometer. The genotoxic impact was quantified based on the number of micronucleated cells per 1,000 analyzed (MN‰), using hemolymph slides stained with Giemsa. Metal concentrations in water were below the detection limit, except for lead, although no significant difference was observed between the areas (P?>?0.05). Sediment from Cubatão had higher concentrations of Cd, Pb, Cr, and Cu than sediment from Juréia-Itatins (P?<?0.05), but no significant differences in metal concentrations were detected among depth strata of the sediment (P?>?0.05). Crabs from Cubatão had a 2.6 times higher mean frequency of micronucleated cells (5.2?±?1.8 MN‰) than those from Juréia-Itatins (2.0?±?1.0 MN‰; P?<?0.0001). The more-polluted conditions found in the mangrove sediments of Cubatão were reflected in the micronucleus assay, demonstrating their genotoxic effect; however, genetic damage should be attributed to a synergistic effect with other kinds of pollutants previously recorded in different environments of Cubatão. U. cordatus proved to be an excellent bioindicator of mangrove pollution. This study established, for the first time, the normal frequency of MN‰ in a population of this species within an ecological station.     

Genotoxicity of the sediments collected from Pearl River in China and their polycyclic aromatic hydrocarbons (PAHs) and heavy metals

The accelerated industrialization and urbanization in the last three decades around the Pearl River Delta within Guangdong Province in China have led to serious concerns about the impacts on the aquatic environment. In the present study, the genotoxicity of the sediments collected from the Pearl River was evaluated by micronucleus (MN) assay with Vicia faba root tip cells, and the 16 EPA priority polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs, including Cr, Cu, As, Se, Cd, Hg, and Pb) in the sediments were determined respectively by GC-MS, inductively coupled plasma mass spectrometry, and inductively coupled plasma atomic emission spectrometry. The results showed that there were significant increases of MN frequencies observed in the sediment-exposed groups, compared with the negative group (P?相似文献   

Comparison of three sampling and analytical methods for the determination of airborne hexavalent chromium

A field study was conducted with the goal of comparing the performance of three recently developed or modified sampling and analytical methods for the determination of airborne hexavalent chromium (Cr(VI)). The study was carried out in a hard chrome electroplating facility and in a jet engine manufacturing facility where airborne Cr(VI) was expected to be present. The analytical methods evaluated included two laboratory-based procedures (OSHA Method ID-215 and NIOSH Method 7605) and a field-portable method (NIOSH Method 7703). These three methods employ an identical sampling methodology: collection of Cr(VI)-containing aerosol on a polyvinyl chloride (PVC) filter housed in a sampling cassette, which is connected to a personal sampling pump calibrated at an appropriate flow rate. The basis of the analytical methods for all three methods involves extraction of the PVC filter in alkaline buffer solution, chemical isolation of the Cr(VI) ion, complexation of the Cr(VI) ion with 1,5-diphenylcarbazide, and spectrometric measurement of the violet chromium diphenylcarbazone complex at 540 nm. However, there are notable specific differences within the sample preparation procedures used in three methods. To assess the comparability of the three measurement protocols, a total of 20 side-by-side air samples were collected, equally divided between a chromic acid electroplating operation and a spray paint operation where water soluble forms of Cr(VI) were used. A range of Cr(VI) concentrations from 0.6 to 960 microg m(-3), with Cr(VI) mass loadings ranging from 0.4 to 32 microg, was measured at the two operations. The equivalence of the means of the log-transformed Cr(VI) concentrations obtained from the different analytical methods was compared. Based on analysis of variance (ANOVA) results, no statistically significant differences were observed between mean values measured using each of the three methods. Small but statistically significant differences were observed between results obtained from performance evaluation samples for the NIOSH field method and the OSHA laboratory method.     

Relationships among varying sampling distance and the IBI in warmwater,headwater streams of the Eastern Corn Belt Plain

Single-pass electrofishing was used to define the most efficient sampling distance to assess stream condition using the index of biotic integrity (IBI) methodology in headwater (<36 km² drainage area), warmwater streams in the Eastern Corn Belt Plain ecoregion. Based on wetted widths (1–3.3 m) of sampled reaches, we defined effort based on increased area (range 50–555 m²). Sampled area necessary to capture a representative fish assemblage increased until 167-m² distance, which is equivalent to a minimum sampling distance of one habitat cycle. No significant difference in metric actual observed value response was found with increasing habitat cycle. Increased effort is required in smaller streams widths (≤1 m) to achieve the recommended sample area. The effect of rare fish on the IBI was tested using a modified Walford method. A significant decrease in IBI score was observed when 10 % of the rare data were removed. The presence of rare fish did not influence individual IBI metrics or scores for either the increased effort or reduced effort calibrations until greater than 3 % of the data was removed for number of species, 15 % removal of data for number of minnow species, and 5 % removal of data for catch per unit effort (CPUE). Increased effort did not affect any metric or IBI score, while reduced effort influenced the number of darter, madtom, and sculpin species and catch per unit effort metric scores but did not affect IBI score.     

Chromium speciation in a contaminated groundwater: redox processes and temporal variability

Chromium species (Cr(III), Cr(VI), and Cr(III)-organic) in groundwater of a tannery contaminated area were monitored during pre- and post-monsoon seasons for a period of 3 years (May 2004 to January 2007). The objectives of the study were (1) to investigate the temporal variation of chromium species and other matrix constituents and (2) to study the redox processes associated with the temporal variation of chromium species. Samples were collected from 15 dug wells and analyzed for chromium species and other constituents. The results showed that the groundwater was relatively more oxidizing during post-monsoon periods than the pre-monsoon periods. Except one sample, the concentration of chromium species were found in the order of Cr(VI)>Cr(III)>Cr(III)-organic complexes during all the pre- and post-monsoon periods. In most of the wells, the concentrations of Cr(III), Cr(VI), and Cr(III)-organic decreased during post-monsoon periods compared to their pre-monsoon concentrations. However, the Cr(VI)/Cr_Total ratio still increased and the Cr(III)/Cr_Total ratio decreased during post-monsoon periods in most of the samples. The possible mechanisms for the temporal variation of chromium species were (1) Fe(II) reduction of Cr(VI) vs oxidation of Fe(II) by dissolved oxygen and (2) oxidation of Cr(III) by Mn(IV).     

Use of two population metrics clarifies biodiversity dynamics in large-scale monitoring: the case of trees in Japanese old-growth forests

An alkaline comet assay and a micronucleus test were carried out on erythrocytes of the European chub, Squalius cephalus L., collected in spring and autumn in 2005 and 2006 at three sampling sites in River Sava, near Zagreb, Croatia. The results of comet assay showed the lowest genotoxic influence at the least polluted site, while higher DNA damage was observed at the polluted sites. Although the basal levels of DNA damage were elevated, a clear gradation of DNA damage was found due to pollution intensity in all sampling periods. The lowest cytogenetic damage as revealed by the micronucleus test (MNT) was observed as well at the least polluted site. High variations in MN frequency were observed between sampling periods, although the number of micronucleated erythrocytes was consistently the highest one at the polluted site. The comet assay as a biomarker of genotoxic effect exhibited higher sensitivity in discriminating the genotoxic capacity of studied polluted sites while the MNT was less sensitive. However, both tests should be used together in biomonitoring studies because they can reveal different aspects of DNA damage; comet assay, the early event of genotoxic exposure, and MNT, its final result as a mutagenic potential.     

Chromium (VI) biosorption properties of multiple resistant bacteria isolated from industrial sewerage

Chromium (VI) [Cr (VI)] biosorption by four resistant autochthonous bacterial strains was investigated to determine their potential for use in sustainable marine water-pollution control. Maximum exchange between Cr (VI) ions and protons on the cells surfaces were at 30–35 °C, pH?2.0 and 350–450 mg/L. The bacterial strains effectively removed 79.0–90.5 % Cr (VI) ions from solution. Furthermore, 85.3–93.0 % of Cr (VI) ions were regenerated from the biomasses, and 83.4–91.7 % of the metal was adsorbed when the biomasses was reused. Langmuir isotherm performed better than Freundlich isotherm, depicting that Cr (VI) affinity was in the sequence Rhodococcus sp. AL03Ni?>?Burkholderia cepacia AL96Co?>?Corynebacterium kutscheri FL108Hg?>?Pseudomonas aeruginosa CA207Ni. Biosorption isotherms confirmed that Rhodococcus sp. AL03Ni was a better biosorbent with a maximum uptake of 107.46 mg of Cr (VI) per g (dry weight) of biomass. The results highlight the high potential of the organisms for bacteria-based detoxification of Cr (VI) via biosorption.