PFOS青春期暴露对成年期雄性大鼠的生殖毒性

为探究青春期的PFOS暴露对成年后的SD大鼠的生殖毒性,对出生后第21天(PND21)的SD大鼠经口灌胃不同剂量的PFOS(5、10和20mg·kg~(-1)),连续染毒7d,在出生后第56天(PND56)时,对各染毒组SD大鼠的体质量、精子数量、血清中的睾酮浓度,以及睾丸间质细胞睾酮合成的相关基因mRNA水平进行了检测。结果显示,10mg·kg~(-1)剂量组大鼠体质量较对照组明显下降(P<0.01);精子数量在10mg·kg~(-1)和20mg·kg~(-1)剂量组明显降低(P<0.05);血清中睾酮浓度随着PFOS剂量的加大有明显下降的趋势,20mg·kg~(-1)剂量组显著低于对照组(P<0.05);类/胆固醇相关基因star和cyp11α1的mRNA表达水平明显下调。研究表明,青春期的PFOS暴露会导致睾酮合成途径中相关因子的功能缺失,破坏成熟睾丸间质细胞的功能,致使睾酮水平降低,并抑制精子生成,从而破坏生殖系统的功能。     

基于气象灾害的青岛市域生态风险评价

根据美国环保局（USEPA）的生态风险评价框架和相对风险模型（Relative Risk Model,RRM）,对青岛市域县级行政区的干旱、洪涝、大风和冰雹4种气象灾害进行了生态风险评价。评价结果表明,研究区内干旱生态风险最为严重,洪涝其次;耕地承受的风险最高,城镇和居民地其次;胶州的生态风险最大,青岛市区其次。而且胶州的干旱灾害、市区的大风灾害、平度的冰雹灾害以及胶南的草地成灾比较突出,成为风险分区的依据。最后,不确定性分析表明RRM不确定性的模拟值与计算值接近,验证了RRM在县级尺度上的适用性;敏感性分析说明相对风险值对干旱等级4最为敏感,且对生境分级敏感程度高于风险源分级。此外,利用生态系统生态服务功能的损失率确定暴露系数,降低了确定暴露系数带来的随机性。同时,生境变化需要进一步考虑以明确生态风险在时间尺度上的变化特点。     

低浓度2,4-DCP对鲫鱼肝脏抗氧化防御系统的影响

 采用室内模拟方法,以2,4-二氯苯酚(2,4-DCP)和小鲫鱼(Carassius auratus)为实验材料,研究了0.1mg/L 2,4-DCP在不同暴露期内对鲫鱼肝脏抗氧化防御系统的影响.结果表明,过氧化氢酶(CAT)、超氧化物歧化酶(SOD)及氧化型谷胱甘肽(GSSG)对2,4-DCP非常敏感,在暴露第2天就受到极显著的诱导或抑制(P<0.01);还原型谷胱甘肽(GSH)含量总体上被抑制;谷胱甘肽还原酶(GR)活性整体上呈现轻微诱导趋势谷胱甘肽过氧化物酶(Se-GPx)活性先受抑制后被诱导;谷胱甘肽硫转移酶(GST)的活性先被诱导,后降低到对照组水平.上述肝脏抗氧化酶指标可作为水生生态系统中2,4-DCP污染的生物监测指标.     

Euro Chlor Risk Assessment for the Marine Environment Osparcom Region: North Sea - 1,2-Dichloroethane

This risk assessment on 1,2-dichloroethane (EDC) was carried out specifically for the marine environment, according to the methodology laid down in the EU risk assessment Regulation (1488/94) and the Guidance Document of the EU New and Existing Substances Regulation (TGD, 1997). The study consists of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programs in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of the "predicted environmental concentrations" (PEC) and the "predicted no effect concentrations" (PNEC) for the marine aquatic environment. In total, 21 studies for fish, 17 studies for invertebrates and 7 studies for algae have been evaluated. Both acute and chronic toxicity studies have been taken into account and the appropriate assessment factors have been used to define a PNEC value of 1100 µg/l. Most of the available monitoring data apply to rivers and estuaries and were used to calculate PECs. The most recent data (1991-1995) support a typical PEC of 0.5 µg EDC/l and a worst case PEC of 6.4 µg EDC/l. The calculated PEC/PNEC ratios give a safety margin of 170 to 2200 between the predicted no effect concentration and the exposure concentration. Additional evaluation of environmental fate and bioaccumulation characteristics showed that no concern is expected for food chain accumulation.     

Euro Chlor Risk Assessment for the Marine Environment Osparcom Region: North Sea - Chloroform

This risk assessment on chloroform was carried out specifically for the marine environment, according to the methodology laid down in the EU risk assessment Regulation (1488/94) and the Guidance Document of the EU New and Existing Substances Regulation (TGD, 1997). The study consists of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programs in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of the "predicted environmental concentrations" (PEC) and the "predicted no effect concentrations" (PNEC) for the marine aquatic environment. In total, 23 studies for fish, 17 studies for invertebrates and 10 studies for algae have been evaluated. Both acute and chronic toxicity studies have been taken into account and the appropriate assessment factors have been used to define a typical PNEC value of 72 µg/l. Due to limitations of the studies evaluated, a worst PNEC of 1 µg/l could also be used. Most of the available monitoring data apply to rivers and estuaries and were used to calculate PECs. The most recent data (1991-1995) support a typical PEC of 0.2 µg chloroform per litre of water and a worst case PEC of 5 to 11.5 µg chloroform per litre of water. The calculated PEC/PNEC ratios give a safety margin of 6 to 360 between the predicted no effect concentration and the exposure concentrations. A worst case ratio, however, points to a potential risk for sensitive species. Refinement of the assessment is necessary by looking for more data. Additional evaluation of environmental fate and bioaccumulation characteristics showed that no concern is expected for food chain accumulation.     

Euro Chlor Risk Assessment for the Marine Environment Osparcom Region: North Sea - Tetrachloroethylene

This risk assessment on tetrachloroethylene (PER) was carried out specifically for the marine environment, according to the methodology laid down in the EU risk assessment Regulation (1488/94) and the Guidance Document of the EU New and Existing Substances Regulation (TGD, 1997). The study consists of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programs in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of the "predicted environmental concentrations" (PEC) and the "predicted no effect concentrations" (PNEC) for the marine aquatic environment. In total, 18 studies for fish, 13 studies for invertebrates and 8 studies for algae have been evaluated. Both acute and chronic toxicity studies have been taken into account and the appropriate assessment factors have been used to define a PNEC value of 51 µg/l. Most of the available monitoring data apply to rivers and estuary waters and were used to calculate PECs. The most recent data (1991-1995) support a typical PEC of 0.2 µg PER/l water and a worst case PEC of 2.5 µg PER/l water. The calculated PEC/PNEC ratios give a safety margin of 20 to 250 between the predicted no effect concentration and the exposure concentration. Additional evaluation of environmental fate and bioaccumulation characteristics showed that no concern is expected for food chain accumulation.     

Euro Chlor Risk Assessment for the Marine Environment Osparcom Region: North Sea - 1,1,2-Trichloroethane

This risk assessment on 1,1,2-trichloroethane (T112) was carried out specifically for the marine environment, according to the methodology laid down in the EU risk assessment Regulation (1488/94) and the Guidance Document of the EU New and Existing Substances Regulation (TGD, 1997). The study consists of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programs in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of the "predicted environmental concentrations" (PEC) and the "predicted no effect concentrations" (PNEC) for the marine aquatic environment. In total, 22 studies for fish, 45 studies for invertebrates and 9 studies for algae have been evaluated. Both acute and chronic toxicity studies have been taken into account and the appropriate assessment factors have been used to define a PNEC value of 300 µg/l. Most of the available monitoring data apply to rivers and estuaries and were used to calculate PECs. The most recent data (1991-1995) support a typical PEC of 0.01 µg T112/l water and a worst case PEC of 5 µg T112/l water. The calculated PEC/PNEC ratios give a safety margin of 60 to 30,000 between the predicted no effect concentration and the exposure concentration. Additional evaluation of environmental fate and bioaccumulation characteristics showed that no concern is expected for food chain accumulation.     

珠三角地区臭氧来源特征的数值模拟研究

采用WRF/CAMx模型及臭氧源解析技术(OSAT)模块研究珠三角地区臭氧季节性时空分布特征,对不同污染天气型下的臭氧来源进行解析,评估珠三角各城市臭氧暴露水平,并探究如何根据实际天气状况为不同城市提出切实有效的管控措施.研究结果表明,珠三角地区臭氧浓度遵循夏秋季高、冬季低的季节变化特征.在所有季节中,珠三角地区以外的...     

垃圾焚烧厂周边大气二噁英含量及变化特征——以北京某城市生活垃圾焚烧发电厂为例

2013年4月至2014年1月对北京市某生活垃圾焚烧厂周边4km范围内5个采样点环境空气中二噁英含量、组成特征及季节变化特征进行了分析.结果表明该垃圾焚烧厂周边环境空气中PCDD/Fs质量浓度的变化范围为8.3~115pg/m³,毒性当量(TEQ)变化范围为0.11~1.9pg I-TEQ/m³,其中秋季1个采样点和冬季全部采样点超出日本环境空气质量标准限值(0.6pg I-TEQ/m³).1,2,3,4,6,7,8-HpCDF和OCDF均是四季空气中PCDD/Fs质量浓度的主要贡献单体,而2,3,4,7,8-PeCDF是总TEQ贡献最大的单体.空间分布特征表现为近源点位(~400m)浓度水平较高而其他点位(>1000m)浓度水平与距污染源距离远近没有显著相关性;季节变化特征表现为冬季值显著高于其他季节,分析可能与冬季采暖及大气扩散条件差导致的大气整体污染较重有关.样品中二噁英同族体及异构体分布指纹谱图与焚烧设施排放烟气存在差别,主成分分析(PCA)源解析结论与指纹谱图特征分析结论一致,体现为多种污染源共同作用的影响.二噁英呼吸暴露剂量估算结果表明该区域人群呼吸暴露风险总体处于较为安全的水平(0.034~0.161pg I-TEQ/(kg·d)),但仍需关注大气重污染天气发生时的呼吸暴露风险.     

Environmental fate and bioavailability of agent orange and its associated dioxin during the vietnam war

BACKGROUND: In 1996, the Committee on the Assessment of Wartime Exposure to Herbicides in Vietnam of the National Academy of Sciences' Institute of Medicine (IOM) issued a report on an exposure model for use in epidemiological studies of Vietnam veterans. This exposure model would consider troop locations based on military records; aerial spray mission data; estimated ground spraying activity; estimated exposure opportunity factors; military indications for herbicide use; and considerations of the composition and environmental fate of herbicides, including changes in the TCDD content of the herbicides over time, the persistence of TCDD and herbicides in the environment, and the degree of likely penetration of the herbicides into the ground. When the final report of the IOM Committee was released in October 2003, several components of the exposure model envisioned by the Committee were not addressed. These components included the environmental fate of the herbicides, including changes in the TCDD content over time, the persistence of TCDD and herbicides in the environment, and the degree of likely penetration of herbicides into the ground. This paper is intended to help investigators understand better the fate and transport of herbicides and TCDD from spray missions, particularly in performing epidemiological studies. METHODS: This paper reviews the published scientific literature related to the environmental fate of Agent Orange and the contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and discusses how this affected the potential exposure to TCDD of ground troops in Vietnam. Specifically, the mechanisms of dissipation and degradation as they relate to environmental distribution and bioavailability are addressed. RESULTS: The evaluation of the spray systems used to disseminate herbicides in Vietnam showed that they were capable of highly precise applications both in terms of concentrations sprayed and area treated. Research on tropical forest canopies with leaf area indices (a measure of foliage density) from 2 to 5 indicated that the amount of herbicide and associated TCDD reaching the forest floor would have been between 1 and 6% of the total aerial spray. Studies of the properties of plant surface waxes of the cuticle layer suggested that Agent Orange, including the TCDD, would have dried (i.e., be absorbed into the wax layer of the plant cuticle) upon spraying within minutes and could not be physically dislodged. Studies of Agent Orange and the associated TCDD on both leaf and soil surface have demonstrated that photolysis by sunlight would have rapidly decreased the concentration of TCDD, and this process continued in shade. Studies of 'dislodgeable foliar residues' (DFR, the fraction of a substance that is available for cutaneous uptake from the plant leaves) showed that only 8% of the DFR was present 1 hr after application. This dropped to 1% of the total 24 hrs after application. Studies with human volunteers confirmed that after 2 hrs of saturated contact with bare skin, only 0.15-0.46% of 2,4,5-T, one of the phenoxy acetic acid compounds that was an active ingredient of Agent Orange, entered the body and was eliminated in the urine. CONCLUSIONS: The prospect of exposure to TCDD from Agent Orange in ground troops in Vietnam seems unlikely in light of the environmental dissipation of TCDD, little bioavailability, and the properties of the herbicides and circumstances of application that occurred. Photochemical degradation of TCDD and limited bioavailability of any residual TCDD present in soil or on vegetation suggest that dioxin concentrations in ground troops who served in Vietnam would have been small and indistinguishable from background levels even if they had been in recently treated areas. Laboratory and field data reported in the literature provide compelling evidence on the fate and dislodgeability of herbicide and TCDD in the environment. This evidence of the environmental fate and poor bioavailability of TCDD from Agent Orange is consistent with the observation of little or no exposure in the veterans who served in Vietnam. Appreciable accumulation of TCDD in veterans would have required repeated long-term direct skin contact of the type experienced by United States (US) Air Force RANCH HAND and US Army Chemical Corps personnel who handled or otherwise had direct contact with liquid herbicide, not from incidental exposure under field conditions where Agent Orange had been sprayed.