Indices of Benthic Community Tolerance in Contaminated Great Lakes Sediments: Relations with Sediment Contaminant Concentrations, Sediment Toxicity, and the Sediment Quality Triad

We evaluated the toxic-units model developed by Wildhaber and Schmitt (1996) as a predictor of indices of mean tolerance to pollution (i.e., Lenat, 1993; Hilsenhoff, 1987) and other benthic community indices from Great Lakes sediments containing complex mixtures of environmental contaminants (e.g., polychlorinated biphenyls – PCBs, polycyclic aromatic hydrocarbons – PAHs, pesticides, chlorinated dioxins, and metals). Sediment toxic units were defined as the ratio of the estimated pore-water concentration of a contaminant to its chronic toxicity as estimated by U.S. Environmental Protection Agency Ambient Water Quality Criteria (AWQC) or other applicable standard. The total hazard of a sediment to aquatic life was assessed by summing toxic units for all contaminants quantified. Among the benthic community metrics evaluated, total toxic units were most closely correlated with Lenat's (1993) and Hilsenhoff's (1987) indices of community tolerance (T _L and T _H , respectively); toxic units accounted for 42% T _L and 53% T _H of variability in community tolerance as measured by Ponar grabs. In contrast, taxonomic richness and Shannon-Wiener diversity were not correlated (P > 0.05) with toxic units. Substitution of order- or family-level identifications for lowest possible (mostly genus- or species-) level identifications in the calculation of T _L and T _H indices weakened the relationships with toxic units. Tolerance values based on order- and family-level identifications of benthos for artificial substrate samples were more strongly correlated with toxic units than tolerance values for benthos from Ponar grabs. The ability of the toxic-units model to predict the other two components (i.e., laboratory-measured sediment toxicity and benthic community composition) of the Sediment Quality Triad (SQT) may obviate the need for the SQT in some situations.     

Contamination Levels and Preliminary Assessment of the Technical Feasibility of Employing Natural Attenuation in 5 Priority Areas of Presidente Bernardes Refinery in Cubatão, São Paulo, Brazil

Five priority areas of potential impact by contaminants (API) were investigated at the Presidente Bernardes Refinery in Cubatão, São Paulo, Brazil with the following aims: (i) to identify both organic and inorganic contaminants present in soil and groundwater; (ii) to define the environmental conditions relevant for microbial activity at the site and (iii) to evaluate the feasibility of employing natural attenuation for treatment of the hydrocarbon contamination. One area (API 1) was an uncontrolled landfill, where waste materials from the refinery were deposited between 1954 and 1986, and four areas (API 4, 5, 7 and 11) were located in the operational section of the refinery. Soil contamination by regulated BTEX compounds (benzene, toluene, total xylenes) was restricted to two samples from API 1. Nonregulated ethylbenzene was detected in one soil sample from API 4, one from API 5 and two from API 1. No soil contained regulated PAH above threshold levels. Several nonregulated PAHs were found in 6 soil samples from API 1, 3 soil samples from API 4 and 1 soil sample from API 5. Site soils contained very high aluminium concentrations, but metal contamination was restricted to one soil sample from API 1, which contained nickel above threshold limits. BTEX contamination of groundwater was due mostly to benzene. Of the 17 PAH molecules tested, only naphthalene and 2-methylnaphthalene occurred in groundwater. The sum of total BTEX and total PAH exceeded 200 μg/L in only a few monitoring wells in API 4, 5 and 11 and was always below 2.640 μg/L. Be, Cd, Cr, Cu, Hg, Ni, Se, Ag, Tl and Zn were not detected in groundwater, which was contaminated in a few locations by aluminium (mostly below 1 mg/L), lead (<0.066 mg/L) and arsenic (<0.056 mg/L). S, K, Ca, Mg and Fe were present in groundwater in excess of physiological requirements for microbial growth, but low concentrations of N and P could become growth limiting. However, BTEX were efficiently degraded in saturated and unsaturated zone microcosms and nutrient amendments did not stimulate biodegradation rates measurably. The inorganic carbon pool in groundwater was up to one order of magnitude larger than the organic carbon pool. Total inorganic carbon (TIC) in API groundwater exceeded TIC of clean groundwater by factors of 2 (API 4), 6 (API 5, 7 and 11) or 10 (API 1). Most of the inorganic carbon incorporated into groundwater beneath the refinery originated from biodegradation in the unsaturated soil, which contained a microbiota (10⁶ cells/g on average) capable of growth with most of the pure (benzene, toluene, ethylbenzene and xylene) and mixed hydrocarbons tested (diesel oil, gasoline, naphtha, condensate, aromatic residue and fuel oil). A viscous hydrocarbon paste uncovered in API 1 was insoluble in water but dissolved in dichloromethane. Many organic components of this paste were biodegradable as evidenced by weight reduction of the hydrocarbon paste and by the growth of suspended and attached biomass in saturated zone microcosms, where the paste was the only carbon source. This study indicates that monitored natural attenuation may be a technically feasible and efficient means for plume control in API 1, 4 and 5, provided the plumes in API 4 and 5 are not expanding. This technique is not suitable for contaminant reduction in API 11.     

Identifying areas of high herpetofauna diversity that are threatened by planned infrastructure projects in Spain

A major task related to conservation is to predict if planned infrastructure projects are likely to threaten biodiversity. In this study we investigated the potential impact of planned infrastructure in Spain on amphibian and reptile species, two highly vulnerable groups given their limited dispersal and current situation of population decline. We used distribution data of both groups to identify areas of high herpetofauna diversity, and compared the locations of these areas with the locations of the planned road, high-speed train railway and water reservoir network. Four criteria were used for this identification: species richness, rarity, vulnerability, and a combined index of the three criteria. From a total of 1441 cells of 20 x 20 km, areas of high diversity were defined as those cells whose ranked values for the different criteria included either all species or all threatened species. The combined index provided the smallest number of cells needed to retain all threatened species (1.7 and 2.6% of the cells for amphibian and reptile species, respectively). Coincidences between these high diversity areas and cells including planned infrastructures-denominated 'alert planning units'-were 35.4% for amphibians and 31.2% for reptiles. Mitigation of the potential impacts would include actions such as barriers to animal access to roads and railways and ecoducts under these constructions. Our approach provides conservation authorities information that can be used to make decisions on habitat protection. A technique that identifies threats to herpetofauna before they occur is also likely to improve the chance of herpetofauna being protected.     

炼油废水处理菌剂的研究

根据炼油废水成分分析的结果筛选降解烷烃、苯系物、苯酚等难降解化合物的高效降解菌,通过正交实验确定各组成菌株的最佳配比,制成复合微生物菌剂,根据营养需求添加KH₂PO₄作为助剂.摇瓶实验结果显示相对于只加活性污泥的处理体系,菌剂及助剂投加至活性污泥体系中能够提高处理效率82.14%,将配制的菌剂接种至预先投加活性污泥并稳定运行的SBR反应器后,显示投加菌剂的SBR反应器对炼油废水的处理效率高于对照实验,反应9h后,处理效率能够提高25.39%.     

炼油工业的水资源利用及可持续发展

资源的流失和浪费是造成工业污染的根源,为了保护环境、使国民经济得到可持续发展,必须科学、合理地利用水资源,努力探求水资源利用的最优化、再资源化。文章针对炼油工业水资源的使用情况,将资源利用和环境保护结合起来加以分析,并对今后的技术发展方向进行了探讨。     

DETERMINATION OF CROP PRODUCTION LOSS DUE TO INADEQUATE DRAINAGE IN A LARGE WATERSHED1

ABSTRACT Results of a field survey designed to assess the extent of crop production losses due to inadequate drainage in a large watershed of Iowa is presented. Information on the current status of drainage of the watershed, located in the Des Moines River basin, was collected through personal interviews with 256 farmers from 60 legal drainage districts. The results of the survey indicate that 95 percent of the area in upper Des Moines River basin has inadequate district mains or main outlet drains currently having a design capacity of ≤ 0.64 cm/day drainage coefficient. Outlet capacity of 1.27 cm/day d.c. would be required for full production. Inadequate drainage in the watershed is currently responsible for crop yield reduction equal to about one-third of the maximum yield potential for average weather conditions.     

Ecology and seasonal variation of microalgal community in an oil refinery effluent holding pond: monitoring and assessment

The microalgal community as primary producers has to play a significant role in the biotic and abitoic interactions of anyaquatic ecosystem. Whenever a community is exposed to a pollutant, responses can occur because individuals acclimate topollutant caused changes and selection can occur favouring resistant genotypes within a population and selection among species can result in changes in community structure. The microalgal community of industrial effluent treatment systems arecontinuously exposed to pollutants and there is little data available on the structure and seasonal variation of microalgalcommunity of industrial effluent holding ponds, especially of acomplex effluent like that of refinery. The aim of the presentstudy was to investigate the annual variation in the ecology,biomass, productivity and community structure of the algalcommunity of a refinery effluent holding pond. The results ofthe study showed the pond to be a eutrophic system with a resistant microalgal community with distinct seasonal variation in species composition.     

炼油污水的深度处理

论述了炼油污水深度处理的常用技术--过滤、膜分离及化学氧化技术,对炼油污水深度处理进行了中试试验,并结合试验结果对动态砂滤系统、PAN膜处理系统和高级氧化系统处理炼油厂二级排放水的适用性进行了论证。结果表明,二级排放水经动态砂滤系统和NF纳滤系统处理后,COD、氨氮、SS、硫化物、酚、浊度、总铁等指标均达到循环水补水水质要求,可以回用于循环水场;经PAN膜制成的UF超滤和RO反渗透系统处理后,各种污染物指标和盐类指标都降至微量,且脱盐效果明显。     

炼厂脱盐脱钙废水处理工艺

原油中的钙盐主要存在于石油胶质和沥青质中。在原油加工过程中,有机钙盐因分解形成钙沉淀物而影响正常生产。对于原油中钙的脱除,目前应用最广泛的是螯合沉淀脱钙技术。炼厂脱盐脱钙废水中的钙、磷、石油胶质会对污水处理场造成不良影响,因而必须对脱盐脱钙废水进行预处理。预处理工艺包括物理和物理化学手段、生物处理工艺、化学氧化处理技术。技术可行性分析表明,可采用AOP高级氧化技术与生物处理相结合的工艺对脱盐脱钙废水进行预处理。     

MODELING INSTREAM RECREATIONAL BENEFITS1

ABSTRACT: A basic problem in the management of rivers has been how to balance the tradeoffs between instream and out-of-stream uses. Traditionally, the problem has been addressed by optimizing the economic benefits of flow diversions and regulated releases with instream uses as a flow constraint. An alternative method is to model the effect different river flows have on various recreational uses (e.g., boating, fishing) and then use the results as an additional function or piece of information to determine river project operations and benefits. A methodology that is based on multiobjective decision theory and that relates instream recreational preferences to river flow is proposed. The methodology consists of determining, standardizing, and combining recreational benefit functions, and incorporating potential sources of uncertainty into an estimate of total instream benefits. Thus different types of flow patterns, resulting from reservoir regulation (out-of-stream water uses), can be analyzed to determine their potential instream impact. The methodology is applied to the New River Gorge, West Virginia, which has been designated as a National River.