氯代苯类化合物对江水细菌的毒性及QSAR研究

采用细菌生长抑制实验,测定了18种氯苯类化合物对长江水中混合细菌的毒性,得到24 hIC₅₀值,-1gIC₅₀为3.65～4.32,其中,毒性最弱的是氯苯,毒性最强的是1,2,4-三氯苯.选用分子连接性指数法对毒性数据进行定量结构活性关系(QSAR)研究.结果表明,氯苯类化合物对江水细菌的毒性与苯环上取代基的种类、数目和位置有关,价分子连接性指数0XV和7X_CHV能够很好地描述氯苯类化合物对江水细菌的毒性.方程-1gIC₅₀=0.8390XV-25.3727X_CHV+0.802的稳健性很好,该模型的预测值与毒性实测值之间的相关系数达0.948.      

AnnAGNPS模型在九龙江流域农业非点源污染模拟应用

运用连续-分布式参数模型(AnnualizedAgriculturalNonPointSourceModel,AnnAGNPS)进行中国南方山区中等尺度流域———九龙江流域农业非点源污染负荷估算和对流域过程和管理措施的模拟.利用4个典型汇水区校正模型参数,并进一步在九龙江的北溪和西溪两大支流流域验证模型的适宜性.以此为基础模拟西溪总氮负荷为24.76kg/(hm²·a),总磷负荷为0.67kg/(hm²·a);北溪总氮负荷10.28kg/(hm²·a),总磷负荷为0.40kg/(hm²·a).运用AnnAGNPS模型对典型汇水区特定集水单元、西溪和北溪流域的土地利用管理措施进行分别模拟.模拟结果显示坡地种植退耕返林后,天宝仙都集水单元92地表径流、泥沙、总氮和总磷负荷可分别削减了21.6%、25.9%、96%和79.2%;下庄集水单元93地表径流、泥沙总氮和总磷负荷削减率分别为94.1%、54.9%、99.2%,和79.7%;模拟西溪香蕉地改种双季稻,西溪总氮、可溶态氮、总磷和可溶性磷依次削减了23.83%、25.44%、9.08%和19.84%;模拟北溪流域内生猪场全部搬迁,流域出口总氮和可溶态氮的削减率分别为63.54%和76.92%.     

黄河(兰州段)水环境中壬基酚及壬基酚聚氧乙烯醚污染的初步研究

对黄河(兰州段)4个排污点的水样和6个断面各个介质(包括水体、悬浮颗粒物和沉积物)中壬基酚(NP)及壬基酚聚氧乙烯醚(NPnEO)的污染调查结果表明,4个排污点水样中分别含有浓度不等的NP,NPnEO(n=1—11);6个断面采样点中,大分子的NPnEO(n>2)在各个介质中均未检出,水样中NP在0.24—2.10μg·l-1之间,NP1EO在0.060-0.35μg·l-1之间,NP2EO在0.039—0.26μg·l-1之间,说明NPnEO在黄河水体发生了有效降解,但是NPnEO小分子降解产物,特别是NP,持久性加强,在不同断面检测到不同程度的污染;在悬浮颗粒物和沉积物中也检测到了相应的NP,NP1lEO和NP2EO,其浓度均大于水体,而悬浮颗粒物对NP,NP1EO和NP2EO的富集大于沉积物对它们的富集.     

黄河中下游表层沉积物中多氯联苯的污染特征

对采自黄河中下游地区12个站点17个表层沉积物样品中的多氯联苯进行了定量分析测定,并讨论了多氯联苯在沉积物中的污染特征.结果表明:①黄河中下游表层沉积物中多氯联苯的浓度范围为ND—5·98μg·kg~(-1),受污染程度较轻;②沉积物样品中多氯联苯同族体的组成特征非常相似,都以含3—5个氯原子的PCB同族体为主,占多氯联苯总量的94·68%以上,且在大多数样品中含量顺序为:四氯联苯>三氯联苯>五氯联苯;③该地区表层沉积物中多氯联苯的含量与TOC和沉积物的机械组成无明显相关性,这可能与黄河中下游复杂的水利条件和沉积物自身的理化性质有关.     

城市富营养化河道复合酶-原位生物修复技术研究

研究了复合酶类生物激活物质对河道中微生物的作用机理,通过测定河道中微生物的生化呼吸线、细菌数、脱氢酶、纤维素酶、脲酶和磷酸酶的酶活性来表征生物激活物质对河道自净过程的促进作用。研究结果表明,复合酶污水净化剂对微生物活性具有激活作用,累积耗氧量明显增加,酶激活率达到14％～136％,有效增强了水体的自净能力。复合酶原位生物修复技术在上海、北京和福州等多条受严重污染的富营养化河道的工程应用表明,复合酶污水净化剂在不同的地域条件下均可发挥良好的作用,具有安全、高效和适用性广等特点。     

大渡河上游干旱河谷区生态需水研究

为了预测南水北调西线一期工程实施对下游干旱河谷演变的影响,开展了对泸定县城以上大渡河流域干旱河谷区生态需水的研究,结果表明:①干旱河谷生态需水量为能够维系干旱河谷生态功能的基本环境目标、恢复干旱河谷生态景观的生态系统所需求的水量;②研究区干旱河谷总面积1185.00km₂,其中干暖河谷250.11km₂,干温河谷934.89km₂;③考虑输沙需水时,维持研究区干旱河谷的最小生态需水量为156.3×108m3,其中干暖河谷最小为58.8×108m3,干温河谷最小为97.4×108m3,不考虑输沙需水时,最小生态需水量仅为58.3×108m3;④河道外需水量占总生态需水量的5.7%;⑤考虑输沙需水时,研究区干旱河谷的最小生态需水量占总地表水量的68.84%,不考虑输沙需水时其只占总地表水量的25.68%,对生态脆弱区生态需水进行计算时需考虑输沙需水。     

Study of the levels of N‐methylcarbamate pesticides in waters of the river Huelva

A study on the levels of N‐methylcarbamate pesticides and some degradation products in waters of the river Huelva was carried out. This river constitutes the main water supply of the city of Seville at the south west of Spain with a population of almost one million inhabitants. N‐methylcarbamates were extracted from the water by using C‐18 solid phase cartridges. High performance liquid chromatography with UV detection was used to carry out the determinations. Residues of carbaryl, methiocarb sulphoxide and α‐naphthol were found in some of the analysed water samples.     

Reduced complexity models for regional aquatic habitat suitability assessment

Generalizable methods that identify suitable aquatic habitat across large river basins and regions are needed to inform resource management. Habitat suitability models intersect environmental variables to predict species occurrence, but are often data intensive and thus are typically developed at small spatial scales. This study estimated mean monthly aquatic habitat suitability throughout Utah (USA) for Bonneville Cutthroat Trout (Oncorhynchus clarkii utah) and Bluehead Sucker (Catostomus discobolus) with publicly available, geospatial datasets. We evaluated 15 habitat suitability models using unique combinations of percent of mean annual discharge, velocity, gradient, and stream temperature. Environmental variables were validated with observed conditions and species presence observations to verify habitat suitability estimates. Stream temperature, gradient, and discharge best predicted Bonneville Cutthroat Trout presence, and gradient and discharge best predicted Bluehead Sucker presence. Simple aquatic habitat suitability models outperformed models that used only streamflow to estimate habitat for both species, and are useful for conservation planning and water resources decision-making. This modeling approach could enable resource managers to prioritize stream restoration across vast regions within their management domain, and is potentially compatible with water management modeling to improve ecological objectives in management models.     

Shift of Spawning Season and Effects of Climate Warming on Developmental Stages of a Grayling (Salmonidae)

Abstract: River‐dwelling fish, such as European graylings (Thymallus thymallus), are susceptible to changes in climate because they can often not avoid suboptimal temperatures, especially during early developmental stages. We analyzed data collected in a 62‐year‐long (1948–2009) population monitoring program. Male and female graylings were sampled about three times/week during the yearly spawning season in order to follow the development of the population. The occurrence of females bearing ripe eggs was used to approximate the timing of each spawning season. In the last years of the study, spawning season was more than 3 weeks earlier than in the first years. This shift was linked to increasing water temperatures as recorded over the last 39 years with a temperature logger at the spawning site. In early spring water temperatures rose more slowly than in later spring. Thus, embryos and larvae were exposed to increasingly colder water at a stage that is critical for sex determination and pathogen resistance in other salmonids. In summer, however, fry were exposed to increasingly warmer temperatures. The changes in water temperatures that we found embryos, larvae, and fry were exposed to could be contributing to the decline in abundance that has occurred over the last 30–40 years.     

Effect of Pollution On the Occurrence, Distribution and Sulphur Transformation Ability of the Thiobacilli in the River Ganga

The occurrence, distribution and nature of ambient thiobacilli along with their ability to oxidize different sulphur species under simulated natural and in vitro culture conditions were studied in the polluted and unpolluted sites of the River Ganga.

Thiobacillus thioparus, T. thiooxidans and T. denitrificans were isolated from the river water. the former two occurred in both polluted and unpolluted sites, while T. denitrificans occurred in polluted areas only. the paper pulp mill effluent discharge area contained the highest population of T. thioparus. the sewage drainage area showed relatively higher populations of T. thiooxidans and T. denitrificans.

The present study revealed that only biological oxidation of either thiosulphate or elemental sulphur occurred in the river water. All the thiobacilli screened oxidized thiosulphate, and three-fourths of them oxidized elemental sulphur. Some strains were found to be very good acidifiers. in spite of such acidification by the ambient thiobacilli, the pH of the river water remained alkaline. the specific rates of thiosulphate (0.18 -0.51 μMmolh^-1 mg^-1 cell) and sulphur (1.3 - 6.2 Normality day^-1 mg^-1 biomass) oxidations under simulated natural condition were found to be higher in polluted areas when compared with the unpolluted one (sulphur: 0.8 - 1.0 Normality day^-1 mg^-1).

Further, addition of thiouslphate or elemental sulphur in the river water in simulated in vitro condition resulted in the increase of respective oxidation rates. the variations in the natae of pollutants discharged into the river water influenced the oxidation rate of thiosulphate or sulphur.