Passive sampling of PAHs in indoor air in Nepal

PAHs were sampled in ten homes in the Makwanpur region, Nepal. SPMDs and moss bags (Sphagnum girgensohnii) were used as passive samplers. Soot particles on the SPMD surfaces were also analyzed for PAHs. The overall PAH concentrations in SPMDs were significantly higher than those in moss bags. Total PAH mean concentrations of ten houses were 535μg/g lipid for SPMDs and 7.2 μg/g moss (dw) for moss bags. Ratios of phenanthrene/anthracene in indoor SPMDs and particulate matter varied from 2.9 to 3.5 and ratios of fluoranthene/pyrene varied from 1.1 to 1.4. The values for moss bags were respectively 1.7–3.6 and 0.8–2.4. These ratios indicate that the PAHs are from combustion origin. The PAH concentrations in ambient air were estimated as B(a)P TEQs and they were 17–64 times higher than acceptable limit for Finnish community air. Based on PAH levels in the gas phase (SPMD) we may expect PAHs to have an impact on respiratory disease prevalence in Nepalese villages. Both of the sampling methods were feasible in the difficult conditions under which the study was performed.     

长江水系氮磷生态化学计量学空间变化特征及影响因素

氮（N）与磷（P）的化学计量学特征反映了N、P在生态系统过程中的耦合关系。当前对于长江水系中全流域N与P摩尔质量比（N:P）的时空衍化规律及其对人类活动的响应机制仍然缺乏科学认知,难以满足长江流域生态保护的治理理论和管理实践需求。根据长江水系水质监测数据和河流水沙数据,从全流域尺度上阐述长江水系N:P的时空分布特征,识别关键控制因素。结果表明：长江干流的N:P从上游到下游呈下降趋势,均值为92±78,大通站N:P输出为47±16;影响长江水系N:P空间变化的主要因素包括支流汇入、沿途面源输入、城市污水输入、磷矿开采活动以及水库拦截;颗粒态P和溶解态N的输入和截留控制着长江干流N:P的季节性差异。从生态化学计量学的角度,揭示人类活动对长江水系营养盐迁移转化的影响,可为未来长江流域生态修复和治理保护工作提供理论参考。     

Testing the Norwegian phosphorus index at the field and subcatchment scale

Simple risk assessment tools for agricultural phosphorus (P) losses, like the P index, have been developed in the U.S.A. and in some European countries. Despite its popularity, there have been surprisingly few studies, which try to test the index close to the field scale. For Norway, the P index approach comprises the risk related to both the source of P (soil P status, amount of fertilizer and manure as well as method of application, plant P release by freezing and P balance) and the risk related to transport of P (erosion, flooding, surface runoff, contributing distance, modified connectivity, soil profile, subsurface drainage). In this paper, we have applied the Norwegian P index to farmer fields within a small agricultural catchment, the Skuterud catchment (450 ha), in southeastern Norway. The Norwegian P index was tested for two agricultural fields (0.3–0.4 ha) and nine subcatchments (6–65 ha). Total P concentrations in runoff from the 11 study areas were measured during the year from May 2001 to April 2002. Results from the testing showed that the Norwegian P index described 66% of the variation in measured relative total P concentration for fields and subcatchments included in this study. Additionally, the P index was able to detect fields and subcatchments with the highest measured P concentrations. Results also showed that the source factor contributed most to the variation between fields and hence were important for the identification of high-risk areas in Skuterud catchment. It was found that the soil P status described 66% of the variation in the source factor. Among the transport variables, it was found that both erosion risk and contributing distance had an important influence on the transport factor. Overall, the study illustrated the potential of the P index to detect areas with the highest risk of P loss.     

五氯酚(PCP)对鸡肝癌细胞(LMH)毒性效应的机制研究

五氯酚(pentachlorophenol,PCP)是一种持久性有机污染物,广泛用于灭钉螺、木材防腐、除草剂等方面,由于PCP在环境中的持久性和生物累积性,其对生态环境和人类健康造成潜在危害。本文以鸡肝癌细胞系(chicken hepatoma cells,LMH)为受试对象,探讨了PCP对细胞色素P450(CYP450)和抗氧化系统的影响。MTT结果显示LMH细胞经不同浓度PCP暴露后,呈现出先促进细胞增殖后抑制的J-型曲线,PCP对LMH细胞24 h的半数效应浓度(24 h-EC50)为427.52μmol·L~(-1)。LMH细胞在1.56、6.25、25、100μmol·L~(-1)PCP染毒条件下可增加细胞EROD、MROD、PROD和BFC活性,并可使CYP1A、1B、1C、2H及3A家族基因mRNA表达水平升高。LMH细胞在0.4~100μmol·L~(-1)PCP染毒下可显著降低硫酸基转移酶(SULT1B1和SULT 1C1)基因mRNA水平。此外,LMH细胞在6.25、25、100μmol·L~(-1)PCP染毒下可引起细胞内ROS升高,同时PCP(1.56~100μmol·L~(-1))可显著增加细胞内MDA含量和降低GSH/GSSH比值。这些结果表明细胞色素P450(CYP450)基因及酶活性的变化、细胞内ROS和MDA含量及GSH/GSSH可作为评价LMH细胞PCP毒性效应的敏感性生物标志物。此研究在细胞水平上利用多个评价指标研究PCP对细胞的毒性效应,为PCP环境风险评价提供依据。     

Palm oil biodiesel: An assessment of PAH emissions, oxidative potential and ecotoxicity of particulate matter

This work assessed the impact of fuelling an automotive engine with palm biodiesel (pure, and two blends of 10% and 20% with diesel, B100, B10 and B20, respectively) operating under representative urban driving conditions on 17 priority polycyclic aromatic hydrocarbon (PAH) compounds, oxidative potential of ascorbic acid (OP^AA), and ecotoxicity through Daphnia pulex mortality test. PM diluted with filtered fresh air (WD) gathered in a minitunel, and particulate matter (PM) collected directly from the exhaust gas stream (W/oD) were used for comparison. Results showed that PM collecting method significantly impact PAH concentration. Although all PAH appeared in both, WD and W/oD, higher concentrations were obtained in the last case. Increasing biodiesel concentration in the fuel blend decreased all PAH compounds, and those with 3 and 5 aromatic rings were the most abundant. Palm biodiesel affected both OP^AA and ecotoxicity. While B10 and B20 exhibited the same rate of ascorbic acid (AA) depletion, B100 showed significant faster oxidation rate during the first four minutes and oxidized 10% more AA at the end of the test. B100 and B20 were significantly more ecotoxic than B10. The lethal concentration LC50 for B10 was 6.13 mg/L. It was concluded that palm biodiesel decreased PAH compounds, but increased the oxidative potential and ecotoxicity.     

Ozone risk assessment for plants: central role of metabolism-dependent changes in reducing power

The combination of stomatal-dependent ozone flux and total ascorbate level is currently presented as a correct indicator for determining the degree of sensitivity of plants to ozone. However, the large changes in carbon metabolism could play a central role in the strategy of the foliar cells in response to chronic ozone exposure, participating in the supply of reducing power and carbon skeletons for repair and detoxification, and modifying the stomatal mode of functioning. To reinforce the accuracy of the definition of the threshold for ozone risk assessment, it is proposed to also consider the redox pool (NAD(P)H), the ratio between carboxylases and the water use efficiency as indicators of the differential ozone tolerance of plants.     

人工湿地脱氮除磷特性研究

针对流域水体富营养化加剧和二级处理水氮磷指标较高的问题,提出以人工湿地对二级出水继续低耗、理想地脱氮除磷。研究中通过对照不同进水水质条件下,不同结构人工湿地的脱氮除磷效能,探讨了人工湿地内的主要脱氮除磷途径。研究表明,表面流湿地内植物对氨氮吸收／吸附和硝化过程为主要氮转化途径,潜流湿地内直接反硝化过程为主要脱氮途径,脱氮效率30％～40％;磷在人工湿地内主要依赖除磷填料床的物化吸附、共沉淀去除,除磷效率达80％以上。     

菹草残体厌氧分解过程中上覆水的硫酸盐还原特征

在富营养化淡水湖泊中,微生物对水生植物的厌氧分解会导致局部水域泛黑发臭,产生草源性"湖泛"现象,但是当前对上覆水中硫酸盐还原细菌(SRB)在水生植物残体分解中的作用还不甚了解.本研究通过室内模拟实验,分别向湖水(本底硫酸根浓度为40 mg·L~(-1))中添加不同浓度的硫酸根,研究了硫酸根浓度升高对上覆水中SRB参与水生植物菹草(P.crispus)残体分解的影响.结果表明,硫酸根浓度升高显著促进了上覆水中硫酸盐还原作用,实验第50 d时,添加了40 mg·L~(-1)硫酸根实验组(40S)中可溶性硫化物(∑H_2S)为(100.11±5.08) mg·L~(-1),远高于未添加硫酸根对照组(CK)的(46.83±3.79) mg·L~(-1).硫还原细菌如脱硫化弧菌属(Desulfovibrio)、脱硫肠状菌属(Desulfotomaculum)和脱硫微菌属(Desulfomicrobium)在40S中的相对丰度显著高于CK(p0.05),而脱硫化孢弯菌属(Desulfosporosinus)则在CK中的相对丰度更高,这说明硫酸根浓度升高促进了菹草残体厌氧分解过程中某些特定种属SRB的生长繁殖.此外,硫酸根浓度升高也影响了菹草厌氧分解过程中有色溶解有机物(CDOM)组分含量的变化,类腐殖质组分在第63 d的荧光强度显著高于第10 d(p0.05),这说明硫酸根浓度升高促进了菹草厌氧分解过程中类腐殖质的产生.本研究对于进一步认识淡水水体中硫酸盐还原的环境效应及生物学机制具有重要意义,也为富营养化水体生态系统修复提供理论依据.     

人工合成P型沸石对NH4^＋交换特性研究

应用由粉煤灰合成的P型沸石研究对NH_4~ 交换的热力学和动力学特性。结果表明,P型沸石阳离子交换总量为264meq/100g,在其整个阳离子组成范围内对进入的NH_4~ 具有高的选择交换性,该交换过程能自发沿着正方向进行,随着温度的增高,其交换能力也增强。Na~ =NH_4~ 交换过程具有较优越的动力学特性,在16℃和32℃时,P型沸石中NH_4~ 自扩散系数分别为7.14×10~(-10)和1.12×10~(-9)cm~2·s~(-1);活化能为20.74kJ·mol~(-1);活化熵分别为-88.26和-88.71J·(mol·°K)~(-1);自由能分别为43.85和45.26kJ·mol~(-1)。     

壬基酚聚氧乙烯醚对斑马鱼精巢组织的影响

采用半静态水体暴露的方式研究了非离子表面活性剂对成熟雄性斑马鱼精巢组织的影响。用荧光定量PCR(qRTPCR)方法检测试验鱼精巢雌激素受体α(ERα)、雄激素受体(AR)基因以及性激素合成相关细胞色素P450酶类基因(CYP17和CYP19a)的表达,通过组织学观察研究受试鱼精巢结构的变化。结果表明,壬基酚聚氧乙烯醚(NPEO)暴露可以引起雄性斑马鱼精巢组织结构的改变,并影响成年雄性斑马鱼ERα、AR基因和性激素合成相关细胞色素P450酶类基因的表达水平,且10.0 mg·L~(-1)的NPEO暴露可以显著上调CYP19a、ERα和AR基因的表达量,可显著下调斑马鱼精巢中CYP17基因的表达量。在组织学上,0.1 mg·L~(-1)组斑马鱼生精小管内不仅生精小囊数目减少,且管腔中精子数量减少,出现非细胞区域; 1.0和10.0 mg·L~(-1)组可见部分个体精子凝聚于生精小管管腔中央,管腔内空隙明显增大,表现出严重的精子浓缩效应。由此表明,NPEO暴露通过抑制CYP17基因的表达干扰睾酮的合成;同时,NPEO暴露通过诱导CYP19a和ER基因的表达增加内源雌激素的合成,导致斑马鱼精巢中性激素紊乱,最终损伤斑马鱼精巢组织。