北京市大气中多氯联苯的污染水平和分布特征

利用XAD树脂被动采样技术和同位素稀释高分辨气相色谱/高分辨质谱联用法(HRGC/HRMS)研究了2012年11月至2014年1月北京地区大气中多氯联苯(PCBs)的污染现状、区域分布特征及季节性变化规律.结果表明,北京大气中19种PCBs总浓度为8.42—45.2 pg·m-3(平均值23.1 pg·m-3),各采样点全年平均毒性当量范围为0.33—3.33 fg WHO-TEQ m-3(平均值1.85 fg WHO-TEQ m-3).PCB-11浓度范围为27.9—136pg·m-3,平均值为78.2 pg·m-3.大气中的PCBs以低氯代(2—5氯代)PCBs为主.季节变化规律呈现出夏/秋季节PCBs浓度高于冬/春季节的规律;区域分布特征呈现出人口密集的城区大于背景区、工业区大于城区的规律.     

环境空气PM2.5连续监测系统手工采样比对测试

借鉴美国EPA关于PM2.5连续监测仪器手工采样比对测试的性能指标和检测方法,结合我国现行的相关技术规范,选取两种不同原理4种型号典型的进口和国产环境空气PM2.5连续自动监测系统,分别在春、夏、秋、冬这4个季节开展了PM2.5连续自动监测与手工采样测量(重量法)之间的比对测试.研究确定了符合我国环境质量现状和环境监测管理需求的PM2.5连续监测系统与手工采样比对测试(调试)的质控措施要求(手工采样测量结果平行性≤5μg·m-3或5%)和技术指标要求(线性回归方程斜率1±0.15;截距0±10;相关系数≥0.95)以及相应的操作方法,为我国环境空气PM2.5连续自动监测系统的现场有效使用和数据质量保证提供了必要的技术手段和质控方法.     

Plant polyphenols – implications of different sampling,storage and sample processing in biodiversity-ecosystem functioning experiments

Plant polyphenols are involved in important ecosystem processes and may affect nutrient cycling. Previous investigations have demonstrated detrimental effects of suboptimal sample treatment on the quantity of extractable plant polyphenols. We compared leaf polyphenol concentrations of 20 tree species from East China in two sample sets collected under different conditions: (a) according to established protocols and stored more than three years, (b) under conditions optimised for leaf polyphenols. We investigated the variance brought about by suboptimal sample handling as compared to the variance caused by the taxonomic range of species. Family-affiliation explained the largest proportion of variance, whereas sample handling had only minor effects. Reducing the taxonomic range increased the impact of differences in sample handling. Additionally, we showed that the concentrations of leaf polyphenols were phylogenetically more conserved than other leaf traits. Non-metric-multi-dimensional scaling revealed similar ordination patterns for leaf polyphenol concentrations in both sample sets with both ordinations being closely correlated. Finally, we computed separate ordinations including an extended set of leaf traits and found that both analyses led to similar ecological conclusions. Consequently, in studies comprising a wide taxonomic range, the adverse effects of suboptimal sample handling may be overridden by the variation brought about by phylogeny.     

Validation and application of an analytical method for determining pesticides in the gas phase of ambient air

A method for determining atmospheric concentrations of eight pesticides applied to corn and soybean crops in Mato Grosso state, Brazil is presented. The method involved a XAD-2 resin cartridge coupled to a low volume air pump at 2 L min^?1 over 8 hours. Pesticides were recovered from the resin using sonication with n-hexane:ethyl acetate and determined by GC-MS. Good accuracy (76–128%) and precision (CV < 20%) were obtained for atrazine, chlorpyrifos, alpha- and beta-endosulfan, endosulfan sulfate, flutriafol, malathion, metolachlor and permethrin. Method detection ranged from 9.0 to 17.9 ng m^?3. This method was applied to 61 gas phase samples collected between December 2008 and June 2009. Atrazine and endosulfan were detected both in urban and rural areas indicating the importance of atmospheric dispersion of pesticides in tropical areas. The simple and efficient extraction method and sampling system employed was considered suitable for identifying pesticides in areas of intense agricultural production.     

Science or Slaughter: Need for Lethal Sampling of Sharks

Abstract: General consensus among scientists, commercial interests, and the public regarding the status of shark populations is leading to an increasing need for the scientific community to provide information to help guide effective management and conservation actions. Experience from other marine vertebrate taxa suggests that public, political, and media pressures will play an increasingly important part in setting research, management, and conservation priorities. We examined the potential implications of nonscientific influences on shark research. In particular, we considered whether lethal research sampling of sharks is justified. Although lethal sampling comes at a cost to a population, especially for threatened species, the conservation benefits from well‐designed studies provide essential data that cannot be collected currently in any other way. Methods that enable nonlethal collection of life‐history data on sharks are being developed (e.g., use of blood samples to detect maturity), but in the near future they will not provide widespread or significant benefits. Development of these techniques needs to continue, as does the way in which scientists coordinate their use of material collected during lethal sampling. For almost half of the known shark species there are insufficient data to determine their population status; thus, there is an ongoing need for further collection of scientific data to ensure all shark populations have a future. Shark populations will benefit most when decisions about the use of lethal sampling are made on the basis of scientific evidence that is free from individual, political, public, and media pressures.     

Estimating Suspended Solids from Turbidity in the Robeson Creek,NC Watershed

The purpose of this project was to assess the effect of estimating total suspended solids (TSS) concentrations from turbidity on TSS loads for streams in the Robeson Creek watershed. Discharge was monitored continuously and base‐flow grab and storm event composite samples were collected and analyzed for TSS and turbidity from five sites during five years of monitoring. For base‐flow samples, the TSS‐turbidity relationship for all five sites was poor indicating that TSS concentrations in base flow cannot be estimated from a TSS‐turbidity relationship. To test the effect of analyzing fewer samples, TSS from every third and the first 20 samples collected from each site was used to develop TSS‐turbidity relationships. In addition, the TSS‐turbidity relationship developed from the most downstream site was used to estimate TSS concentrations from turbidity measured at the other four sites. For four of the five sites, analyzing every third sample for TSS and using the TSS‐turbidity relationship to estimate the missing TSS concentrations would result in mean TSS loads that were not significantly different from the observed. Using the TSS‐turbidity relationship from the outlet to estimate TSS from turbidity measured at the other four sites resulted in significantly different mean TSS loads at three of the four sites. These results indicate that estimating TSS concentrations from turbidity using a TSS‐turbidity relationship developed from a subset of the overall dataset should be done with great caution.     

Novel sampling methods for atmospheric semi-volatile organic compounds (SOCs) in a high altitude alpine environment

High- and low-volume active air samplers as well as bulk deposition samplers were developed to sample atmospheric SOCs under the adverse conditions of a mountain environment. Active sampling employed separate filters for different European source regions. Filters were switched depending on daily trajectory forecasts, whose accuracy was evaluated post hoc. The sampling continued on three alpine summits over five periods of four months. The prevailing trajectories varied stronger between sampling periods than between stations. The sampling equipment (active and bulk deposition) proved dependable for operation in a mountain environment, with idle times being mainly due to non-routine manipulations and connectivity.