PFOS/PFOA环境污染行为与毒性效应及机理研究进展

全氟辛烷磺酰基化合物（PFOS）和全氟辛酸（PFOA）是一类新型的持久性有机污染物（POPs）,近年来发现在环境系统中日益广泛分布,并在生物体内蓄积或发生致毒效应.本文首先从PFOS/PFOA在环境中的污染及其水平、在野生动物体内的暴露、对人体的暴露以及污染与暴露变化趋势等4个方面,分析了PFOS/PFOA最新的环境污染与生物暴露情况;从PFOS/PFOA在大气环境中的转运转化过程、在污水污泥中转运转化过程以及在生物体内的蓄积、代谢转化与降解过程等3个方面,阐述了PFOS/PFOA在环境中的迁移转化行为;还概述了最近几年在PFOS/PFOA所导致的生态效应及其可能的机理研究进展.最后,尝试性地提出了今后在PFOS/PFOA污染生态学方面的研究重点.     

Investigation of exhaled pollutant distribution in the breathing microenvironment in a displacement ventilated room with indoor air stability conditions

This study experimentally studied the dispersion of exhaled pollutant in the breathing microenvironment (BM) in a room equipped with a displacement ventilation (DV) system and indoor air stability conditions (i.e., stable and unstable conditions). The vertical temperature differences and the carbon dioxide (CO₂) concentration in the BM were measured. Results show that when DV is combined with the stable condition (DS), pollutant tends to accumulate in the BM, leading to a high pollutant concentration in this region. Whereas, when DV is combined with the unstable condition (DU), pollutant diffuses to a relatively wider area beyond the BM, thus the pollutant concentration in the BM is substantially reduced. Moreover, increasing the flow rate can reduce the pollutant concentration in the BM of the DS but yields little difference of the DU. In addition, personal exposure intensity increases with time, and the DS has a relatively higher increase rate than DU. The results suggest that indoor air stability will affect the performance of DV systems. DS will lead to a higher health risk for people when they stay in the indoor environment with pollutant sources, and DU is recommended for minimizing pollutant level in the BM in order to reduce the pollutant concentration and providing better air environments for the occupants.     

基于本底格局的鸭绿江口滨海湿地景观破碎化评价

在3S技术支持下构建了鸭绿江口滨海湿地景观本底格局,并以本底格局为参照,分别对1989年和2005年鸭绿江口滨海湿地景观破碎化过程进行了监测评价.结果表明:湿地本底格局可作为强度开发环境下湿地景观格局破碎化评价的参照依据.与本底格局相比,鸭绿江口湿地景观格局呈持续破碎化趋势,1989年和2005年湿地景观整体自然度分别为89.373%和86.691%.在不同自然湿地景观类型中,芦苇沼泽、滩涂和潮沟面积萎缩幅度较大,2005年其自然度分别为69.94%、71.49%和78.42%;各湿地类型的斑块密度都出现了不同程度的增大,其中芦苇沼泽和滩涂增大最明显,2005年斑块相对密度分别达18.507和6.879;滩涂斑块形状趋于复杂,2005年斑块相对形状指数为1.085,其他湿地类型斑块形状则持续简化;各时期不同自然湿地类型斑块聚集度指数均较高,反映出鸭绿江口各湿地类型多呈聚集分布的空间格局.     

Transport and dynamics of toxic pollutants in the natural environment and their effect on human health: research gaps and challenge

The source–pathway–receptor (SPR) approach to human exposure and risk assessment contains considerable uncertainty when using the refined modelling approaches to pollutant transport and dispersal, not least in how compounds of concern might be prioritised, proxy or indicator substances identified and the basic environmental and toxicological data collected. The impact of external environmental variables, urban systems and lifestyle is still poorly understood. This determines exposure of individuals and there are a number of methods being developed to provide more reliable spatial assessments. Within the human body, the dynamics of pollutants and effects on target organs from diffuse, transient sources of exposure sets ambitious challenges for traditional risk assessment approaches. Considerable potential exists in the application of, e.g. physiologically based pharmacokinetic (PBPK) models. The reduction in uncertainties associated with the effects of contaminants on humans, transport and dynamics influencing exposure, implications of adult versus child exposure and lifestyle and the development of realistic toxicological and exposure data are all highlighted as urgent research needs. The potential to integrate environmental with toxicological models provides the next phase of research opportunity and should be used to drive empirical and model assessments.     

铅暴露与排放对中华鲟幼鱼血液中ALT、AST活力的影响

采用水溶液静态置换法,从中华鲟(Acipenser sinensis)受精卵发育至96 h开始,研究了其在0(对照组)、0.2、0.8和1.6mg·L~(-1) Pb~(2+)水溶液中暴露16周,随后排放6周,对中华鲟幼鱼血液中ALT、AST活力的影响.结果显示:Pb暴露后幼鱼血液中的ALT和AST活力均表现为随Pb暴露剂量增加而升高的趋势,1.6mg·L~(-1)组ALT活力与其它各组比较呈极显著差异(P<0.01);0.8和1.6mg·L~(-1)组AST活力与对照组比较分别呈显著差异(P<0.05)和极显著差异(P<0.01). Pb排放后,各暴露组血液中ALT活力降低至对照组水平(P>0.05);1.6 mg·L~(-1)组的AST活力依然较高.超出对照组近2倍(P<0.01).对照组血液的AST/ALT值在2.24～2.32之间;随Pb质量浓度增加,暴露后AST/ALT值呈增加趋势.Pb排放后AST/ALT值降低,但1.6 mg·L~(-1)组与其余各组比较仍维持较高值(P<0.05).初步认为,0.2 mg·L~(-1)和0.8 mg·L~(-1) Pb~(2+)暴露导致中华鲟幼鱼肝细胞不同程度受损,经Pb排放后,轻度受损的组织细胞能够恢复.血液中的AST/ALT值在判断鱼类组织损伤中也具有重要意义.     

MODELING DEVELOPED COASTAL WATERSHEDS WITH THE AGRICULTURAL NON-POINT SOURCE MODEL1

ABSTRACT: Many coastal states are facing increasing urban growth along their coast lines. The growth has caused urban non-point source nitrogen runoff to be a major contributor to coastal and estuarine enrichment. Water resource managers are responsible for evaluating the impacts from point and non-point sources in developed watersheds and developing strategies to manage future growth. Non-point source models provide an effective approach to these management challenges. The Agricultural Non-Point Source Model (AGNPS) permits the incorporation of important spatial information (soils, landuse, topography, hydrology) in simulating surface hydrology and nitrogen non-point source runoff. The AGNPS model was adapted for developed coastal watersheds by deriving urban coefficients that reflect urban landuse classes and the amount of impervious surface area. Popperdam Creek watershed was used for model parameter development and model calibration. Four additional watersheds were simulated to validate the model. The model predictions of the peak flow and total nitrogen concentrations were close to the field measurements for the five sub-basins simulated. Measured peak flow varied by 30 fold among the sub-basins. The average simulated peak flow was within 14 percent of the average measured peak flow. Measured total nitrogen loads varied over an order of magnitude among the sub-basins yet error between the measured and simulated loads for a given sub-basin averaged 5 percent. The AGNPS model provided better estimates of nitrogen loads than widely used regression methods. The spatial distribution of important watershed characteristics influenced the impacts of urban landuse and projecting future residential expansion on runoff, sediment and nitrogen yields. The AGNPS model provides a useful tool to incorporate these characteristics, evaluate their importance, and evaluate fieldscale to watershed-scale urban impacts.     

台湾强震对赣粤闽交界及其沿海地区地震形势的影响

试图通过分析台湾地区与赣粤闽交界及其沿海地区的地质构造背景、动力环境、地震活动的相关性来探讨台湾强震对赣粤闽交界及其沿海地区地震形势的影响 ,从而分析赣粤闽交界及其沿海地区近期的地震趋势。     

Uptake of 17β-estradiol and biomarker responses in brown trout (Salmo trutta) exposed to pulses

In streams, chemicals such as 17β-estradiol (E2) are likely to occur in pulses. We investigated uptake and biomarker responses in juvenile brown trout (Salmo trutta) of 3- or 6-h pulses of concentrations up to 370 ng E2 L⁻¹. Uptake by the fish was estimated from disappearance of E2 from tank water. A single 6-h pulse of 370 ng E2 L⁻¹ increased the plasma vitellogenin concentration, liver Erα- and vitellogenin-mRNA. Exposure to 150-160 ng E2 L⁻¹ for 6 h increased vitellogenin in one experiment but not in another. Two 6-h pulses had a larger effect one pulse. Brown trout in the size range 24-74 g took up E2 linearly with time and exposure concentration with a concentration ratio rate of 20.2 h⁻¹. In conclusion, the threshold for induction of estrogenic effects in juvenile brown trout at short term pulse exposure appears to be in the range 150-200 ng E2 L⁻¹.     

Decontamination trends in the aquacultured fish gilthead seabream (Sparus aurata) after feeding long-term a PCDD/F spiked feed

Aquacultured fish gilthead seabream (Sparusaurata), previously exposed to low levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) trough the diet for a 13 months period, were fed on a clean feed for another 22 months. Gilthead seabream is a protandrous hermaphrodite species and this “decontamination” period coincided with the stages of sex differentiation, maturity and reproduction of the fish. PCDD/F levels in the fish tissues (i.e. muscle, liver, perivisceral fat and gonads), expressed in pg WHO-TEQ g⁻¹ fresh weight, showed a general decreasing trend during the “decontamination” period. However, this general trend varied among tissues and was also dependent on sex and lipid contents. Toxicological effects affecting fish behaviour and hepatic marker responses were also evaluated. The results pointed out that exposure to PCDD/Fs did not have an impact on fish development and reproduction, since the proportion of sexes found after the sex reversal process was within the normal range described for this species. In addition, long-term exposure to low PCDD/F levels did not significantly affect the response of most of the biochemical markers considered. On the contrary, some of them (e.g. EROD activity) showed variations in their responses during the sex differentiation process and onwards. Finally, the hepatic AhR mRNA levels increased during dioxin exposure but they returned to values typical for non-exposed fish after the “decontamination” period.     

Effects of previous sublethal pulse to ammonium nitrate on mortality and total length on Epidalea calamita larvae

Ammonium nitrate is one of the most widespread contaminants related with the viability of natural amphibian populations. In this study we have evaluated in terms of mortality and total length the effects that a previous sublethal pulse to ammonium nitrate generates in Epidalea calamita. Experiments were divided in two phases. In the first one, tadpoles were exposed to two different treatments, with and without a low ammonium nitrate concentration (22 mg NH₄NO₃ L⁻¹). The second phase consisted in static toxicity experiments from both origin treatments with five different nominal concentrations (0, 22, 45, 90 and 180 mg NH₄NO₃ L⁻¹). Results showed that tadpoles that had experienced a previous sublethal exposure showed a negative effect on survival (57% of reduction in the LC₅₀ value) and total length, throughout an increase in their sensitivity. These results could help us to understand the situation of amphibian populations inhabiting aquatic ecosystems exposed to discontinuous and variable pulses of pollutants.