Ecological risk assessment of arsenic and metals in sediments of coastal areas of northern Bohai and Yellow Seas, China

Distributions of arsenic and metals in surface sediments collected from the coastal and estuarine areas of the northern Bohai and Yellow Seas, China, were investigated. An ecological risk assessment of arsenic and metals in the sediments was evaluated by three approaches: the Sediment Quality Guidelines (SQGs) of the United States Environmental Protection Agency (USEPA), the degree of contamination, and two sets of SQGs indices. Sediments from the estuaries of the Wuli and Yalu Rivers contained some of the greatest concentrations of arsenic, cadmium, copper, mercury, lead, and zinc. Median concentrations of cadmium and mean concentrations of lead and zinc were greater than background concentrations determined for the areas. All sediments were considered to be heavily polluted by arsenic, but moderately polluted by chromium, lead, and cadmium. Current concentrations of arsenic and metals are unlikely to be acutely toxic, but chronic exposures would be expected to cause adverse effects on benthic invertebrates at 31.4% of the sites.     

Long-term declines of European insectivorous bird populations and potential causes

Evidence of declines in insect populations has recently received considerable scientific and societal attention. However, the lack of long-term insect monitoring makes it difficult to assess whether declines are geographically widespread. By contrast, bird populations are well monitored and often used as indicators of environmental change. We compared the population trends of European insectivorous birds with those of other birds to assess whether patterns in bird population trends were consistent with declines of insects. We further examined whether declines were evident for insectivores with different habitats, foraging strata, and other ecological preferences. Bird population trends were estimated for Europe (1990–2015) and Denmark (1990–2016). On average, insectivores declined over the study period (13% across Europe and 28% in Denmark), whereas omnivores had stable populations. Seedeaters also declined (28% across Europe; 34% in Denmark), but this assessment was based on fewer species than for other groups. The effects of insectivory were stronger for farmland species (especially grassland species), for ground feeders, and for cold-adapted species. Insectivory was associated with long-distance migration, which was also linked to population declines. However, many insectivores had stable populations, especially habitat generalists. Our findings suggest that the decline of insectivores is primarily associated with agricultural intensification and loss of grassland habitat. The loss of both seed and insect specialists indicates an overall trend toward bird communities dominated by diet generalists.     

Rutabaga roots, a rich source of oviposition stimulants for the cabbage root fly

Summary. Two recently identified compounds ("CIFs"), present on the leaf surface of Brassica oleracea (cabbage), are the strongest oviposition stimulants known for the cabbage root fly, Delia radicum. Cabbage leaves contain these compounds in extremely low concentrations, and the amount of CIFs obtained from purifying leaf extracts was so small that it limited further research. We were able to purify far more of these two compounds from the roots of Brassica napus var. napobrassica (rutabaga). Apart from being a richer source of CIFs, rutabaga roots are considerably easier to collect and process than leaves. In addition, we isolated and identified a new CIF compound from the roots that is also very active in stimulating oviposition in the cabbage root fly. Received 26 May 2000; accepted 26 July 2000     

非点源污染模型研究进展

随着点源污染的有效控制,非点源污染已成为水体污染的主要因素,如何有效地控制和管理非点源污染已成为水环境整治的一项重要任务。而计算机模型是极其有效的流域非点源污染模拟和污染负荷估算的定量化工具,为非点源污染评价、管理和控制提供了可靠依据。文章综述了非点源污染模型的发展概况及其研究不足,并对模型的发展趋势进行了分析和预测。由于非点源污染随机性大、分布范围广、形成机理模糊、管理控制难度大等特点,未来非点源污染的量化模型研究及其与量化模型有关的相应参数研究、模型与GIS集成研究将成为未来研究的主流。     

Application of the “Climafor” baseline to determine leakage: the case of Scolel Té

The acceptance of forestry-based project activities to mitigate greenhouse gases emissions has been subjected to a number of methodological questions to be answered, of which the most challenging are baseline establishment and identification of and measuring leakage. Here we pose hypotheses for and quantify leakage of the Scolel Té project in Chiapas, Mexico. In this project small-scale farmers are implementing forestry, agroforestry, and forest conservation activities, with carbon sequestration as one of the goals. The main leakage monitoring domain is defined as the area owned by the participating farmers or communities outside the area where the specific project activities take place. The null-hypothesis (no leakage) is that non-project land owned by the farmer or community will experience the same carbon stock changes as predicted by the regional baseline, specifically developed for the project. First we assessed the most likely causes and sources of leakage that may occur in the project. From this analysis, one type of leakage seems to be important, i.e., activity shifting. Second we estimated the leakage of a sample of participating farmers and communities. Actual land use was then compared with expected land use derived from the baseline. The Plan Vivo of each participant, complemented with readily available tools to identify the main sources and drivers of leakage are used to develop simple leakage assessment procedures, as demonstrated in this paper. Negative leakage was estimated to be negligible in this study. Incorporating these procedures already in the project planning stage will reduce the uncertainties related to the actual carbon mitigation potential of any forestry project.

Optimization of a novel process for the ozonolysis of 2, 4‐dichlorophenol

An innovative process was studied for the destruction of 2,4‐dichlorophenol in water. The immiscible fluorinated solvent, inert and highly ozone soluble, was used as the solvent in the extraction‐ozonation system. Taguchi methods were applied in the design of experiments to identify the significant factors and establish the optimal combination of process parameters. The result indicate that this statistical technique can provide an extremely effective structured approach.     

Environmental impact minimization of a total wastewater treatment network system from a life cycle perspective

Synthesis of distributed wastewater treatment plants (WTPs) has focused on cost reduction, but never on the reduction of environmental impacts. A mathematical optimization model was developed in this study to synthesize existing distributed and terminal WTPs into an environmentally friendly total wastewater treatment network system (TWTNS) from a life cycle perspective. Life cycle assessment (LCA) was performed to evaluate the environmental impacts of principal contributors in a TWTNS. The LCA results were integrated into the objective function of the model. The mass balances were formulated from the superstructure model, and the constraints were formulated to reflect real wastewater treatment situations in industrial plants. A case study validated the model and demonstrated the effect of the objective function on the configuration and environmental performance of a TWTNS. This model can be used to minimize environmental impacts of a TWTNS in retrofitting existing WTPs in line with cleaner production and sustainable development.