Einfluss organischer Substanz auf die Reproduktion, Biomasse und Akkumulation hydrophober Schadstoffe in Lumbriculus variegatus

Background, aim, and scope Sediment-Water Toxicity Tests are an important instrument for the environmental risk assessment of native, contaminated sediments within the European Water Framework Directive. Thus, it must be guaranteed to distinguish between natural and anthropogenic adverse effects. The content of particulate (POC) and dissolved (DOC) organic carbon can affect the mobility of sediment pollutants. Different studies demonstrated that the DOC-content can influence the bioavailability of contaminants and can directly affect aquatic organisms. The aim of this study was to investigate the influence of increasing sediment organic matter on reproduction and growth of the benthic oligochaete Lumbriculus variegatus. Furthermore, the accumulation factors of the hydrophobic substances 1,1-dichloro-2,2-bis(p-chlorphenyl)ethylene (p,p'-DDE), 2´, 3, 4, 4´, 5´-Hexachlorbiphenyl (PCB 138) und 2, 2´, 4, 4´, 5, 5´-Hexachlorbiphenyl (PCB 153) were calculated considering the TOC-content and the uptake route (water-only exposure or sediment ingestion). Materials and methods The test was performed according to the OECD Guideline 225 (2007) using artificial sediment with different peat concentrations. The effect of an increasing TOC-concentration was studied in three different testmodifications with and without spiked sediment. The nominal concentration of the contaminants in spiked sediment was 50?µg/kg. Results The results showed maximum accumulation factors of 13 for both, PCB 138 and 153 and 11 for p,p'-DDE in sediments with low organic carbon content. With increasing peat content accumulation factors decreased. Thereby the ingestion of sediment was the main exposure route. Moreover preponderantly negative correlations between the organic carbon content in unspiked sediments and reproduction as well as growth of the testorganisms were detected. In combination with the test substances reproduction and growth increased with increasing organic carbon content. Discussion Hence it can be assumed that organic matter, especially humic substances, directly effected the testorganisms in the tests without spiked sediment. Due to the decrease of accumulation factors in spiked sediment with increasing TOC-content it might be possible that the availability of humic substances was reduced by conglomeration with the tested chemicals. Conclusions Therefore the possible influence of dissolved organic matter on the testorganism should be considered when assessing the results of toxicity tests and bioaccumulation studies with Lumbriculus variegatus. Recommendations and perspectives To receive detailed information about a critical DOC-concentration influencing the testorganisms further investigations about the amount of organic matter in the sediment and the DOC-concentration in the overlaying water are recommended.     

Simultaneous Sulfur Dioxide and Nitrogen Dioxide Removal by Calcium Hydroxide and Calcium Silicate Solids

ABSTRACT

At conditions typical of a bag filter exposed to a coal-fired flue gas that has been adiabatically cooled with water, calcium hydroxide and calcium silicate solids were exposed to a dilute, humidified gas stream of nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) in a packed-bed reactor. A prior study found that NO₂ reacted readily with surface water of alkaline and non-alkaline solids to produce nitrate, nitrite, and nitric oxide (NO). With SO₂ present in the gas stream, NO₂ also reacted with S(IV), a product of SO₂ removal, on the exterior of an alkaline solid. The oxidation of S(IV) to S(VI) by oxygen reduced the availability of S(IV) and lowered removal of NO₂. Subsequent acidification of the sorbent by the removal of NO₂ and SO₂ facilitated the production of NO. However, the conversion of nitrous acid to sulfur-nitrogen compounds reduced NO production and enhanced SO₂ removal. A reactor model based on empirical and semi-empirical rate expressions predicted rates of SO₂ removal, NO₂ removal, and NO production by calcium silicate solids. Rate expressions from the reactor model were inserted into a second program, which predicted the removal of SO₂ and NO_x by a continuous process, such as the collection of alkaline solids in a baghouse. The continuous process model, depending upon inlet conditions, predicted 30-40% removal for NO and 50-90% removal for SO₂. These x 2 results are relevant to dry scrubbing technology for combined SO₂ and NO_x removal that first oxidizes NO to NO₂ by the addition of methanol into the flue duct.     

Ecological Benefits of the Conservation Reserve Program

The Conservation Reserve Program was initiated in 1985 to reduce soil loss on highly erodible agricultural land. This stated objective of the program has been quite successful. However, there are other unintentional yet significant ecological benefits to the program that merit evaluation. These benefits include the reversal of landscape fragmentation, maintenance of regional biodiversity, creation of wildlife habitat, and favorable changes in regional carbon flux. These and other benefits should be used by policy makers and federal officials to maintain the program even after enrollment expectations have been achieved.     

Coke,smoke and national sovereignty: a case study of the role of planning in controlling pollution

The controversy surrounding planning approval for certain developments associated with a proposal to generate electricity from gas produced at a large coke works is examined. Although the case begins as another conflict in the ‘planning versus pollution control jurisdiction’ tradition, these concerns are eventually superseded by the wider implications for planning of a residents group's attempt to advance its campaign against this long‐standing ‘bad neighbour’ by citing the principle of the ‘direct effect’ of a European Community directive on industrial air pollution.     

Investment policies in the base metal mining industries and their impact on price cycles

Investment in increased capacity of the major metal producers is examined in the light of changing metal prices and the business cycle. Historically, as metal prices rise, the producers have invested in new mine capacity. This process results in increased production which often comes on stream just as the business cycle is beginning to wane. During the present business cycle the investment pattern of the major mining companies appears to have broken with this historical pattern in that investment strategies are less directed toward increasing capacity.     

Ideal dominance distributions: a test using red-winged blackbirds (Agelaius phoeniceus)

Summary The ideal dominance distribution model predicts that competition between individuals of a species for territories will result in socially dominant individuals acquiring territories in higher quality habitat than their subordinates. Although the dispersion and relative reproductive success of male red-winged blackbirds (Agelaius phoeniceus) across habitats in eastern Ontario appears to conform to the ideal dominance distribution model, data from a study of three captive groups comprised of males from both high (marsh) and low (upland field) quality habitats failed to support the prediction that males from marsh habitat are dominant to those from upland habitat. Contrary to the prediction males from uplands were generally dominant to males from marshes. We found a significant positive correlation between dominance and both increased epaulet size and increased body size. Controlling for these positive effects, upland males remained generally dominant to marsh males. Measurements of independent samples of males from both habitats indicated that the overall distribution of males does not conform to ideal dominance. We suggest that the strong between-year territory fidelity shown by male red-winged blackbirds and chance events when they initially acquire territories may contribute to this lack of conformity.     

Occupant behavior in a six-storey office building fallowing severe earthquake damage

In the Imperial County, California, earthquake of 15th October 1979, the Imperial County Services Building was seriously damaged — and has subsequently been demolished. At the time of the earthquake there were approximately 123 occupants in the six-storey reinforced concrete building which housed a number of county service departments. This paper investigates occupant behavior in a building subjected to an earthquake, and describes, in detail, what people do during and immediately subsequent to the shock.     

Conservation planning at the landscape scale: A landscape ecology method for regional land trusts

This paper illustrates a landscape ecology approach for land trusts undertaking conservation at the watershed scale. A conservation plan was created for the Grand Traverse Regional Land Conservancy (GTRLC) in the headwaters of Michigan's Manistee River Watershed (USA). Eight conservation drivers were devised to identify Conservation Focus Areas (CFAs) of highest ecological importance. The CFAs were ranked based on ecological importance, feasibility of protection and size. Parcels were ranked, totalling nearly 5000 ha, within the three highest-ranking CFAs in one key county. This approach is useful to land trusts trying to operationalize three distinct goals in conservation planning: to find areas of high ecological importance, to promote the landscape's spatial integrity and to delineate threats to ecological systems and processes.