Hysteresis in Reversal of Central European Mountain Lakes from Atmospheric Acidification

Extremely high emissions of S and N compounds in Central Europe (both 280 mmol m^-2 yr^-1) declined by 70and 35%, respectively, during the last decade. Decreaseddeposition rates of SO₄ ^-2, NO₃ ^-, and NH₄ ⁺ in the region paralleled emission declines. The reduction in atmospheric inputs of S and N to mountain ecosystemshas resulted in a pronounced reversal of acidification in the Tatra Mountains and Bohemian Forest lakes. Between the 1987–1990and 1997–1999 periods, concentrations of SO₄ ^-2 and NO₃ ^- decreased (average ± standard deviation) by 22±7 and 12±7 mol L^-1, respectively, in theTatra Mountains, and by 19±7 and 15±10 mol L^-1, respectively, in the Bohemian Forest. Their decrease was compensated in part (1) by a decrease in Ca²⁺ + Mg²⁺ (17±7 mol L^-1) and H⁺ (4±6 mol L^-1), and an increase in HCO₃ ^-(10±10 mol L^-1) in the Tatra Mountains lakes, and (2) by a decrease in Al (7±4 mol L^-1), Ca²⁺ + Mg²⁺ (9±6 mol L^-1), and H⁺ (6±5 mol L^-1), in Bohemian Forest lakes. Despite the rapid decline in lake water concentrations of SO₄ ^-2 and NO₃ ^- in response to reduced S and N emissions, their present concentrations in some lakes are higher than predictionsbased on observed concentrations at comparable emission rates during development of acidification. This hysteresis in chemical reversal from acidification has delayed biological recovery of the lakes. The only unequivocal sign of biological recovery hasbeen observed in erné Lake (Bohemian Forest) where a cladoceran species Ceriodaphnia quadrangular has recentlyreached its pre-acidification abundance.     

Levels of some polybrominated diphenyl ether (PBDE) flame retardants along the Dutch coast as derived from their accumulation in SPMDs and blue mussels (Mytilus edulis)

Aqueous concentrations of individual brominated diphenyl ethers (BDEs) were determined for five stations in the Scheldt estuary and the North Sea along the Dutch coast using passive sampling by semipermeable membrane devices (SPMDs). Values of 0.1-5 pg l(-1) were observed. The highest levels were found in the Scheldt estuary. Concentration differences between February and October were a factor of 4-8 for BDE209, and were smaller than a factor of 2 for the other BDEs. Bioaccumulation was studied for native mussels and for mussels that were transplanted from an uncontaminated area into the Scheldt estuary for 6 weeks. Concentrations in native mussels were higher by a factor of 10 and 2 for BDEs and PCBs, respectively. Field based bioaccumulation factors (BAFs) were higher for BDEs than for PCBs by a factor of 10. Depuration experiments showed that the larger part of the BDE209 content in mussels was associated with ingested particles, whereas no such effect was observed for the other BDEs or PCBs.     

Mutagenicity and organic halogen determination in body fluids and tissues of rats treated with drinking water and pulp mill bleachery effluent concentrates

Concentrates of either drinking water or chlorination stage pulp mill effluent were injected intraperitonally into rats. Urine, feces, liver, and adipose tissues were tested for mutagenic activity and analysed for organic halogen. For both sample types nearly all the organic halogen taken up, eighteen percent from the chlorination stage sample and four percent from the drinking water sample, was excreted via the urine during the first day. Weak mutagenic activity could only be found in the urine collected the first day from animals treated with the highest dose of drinking water.     

What drives plan implementation? Plans,planning agencies and developers

This article investigates the determinants of plan implementation by applying a recently‐developed Plan Implementation Evaluation methodology. The lack of methodology to assess the implementation of plans has so far precluded any systematic analysis of the determinants of the implementation of local environmental plans. The article focuses on the implementation of plans in New Zealand. The key factors of implementation are: the quality of the plan; the capacity and commitment of land developers to implement plans; the capacity and commitment of the staff and leadership of planning agencies to implement plans; and the interactions between developers and the agency. The analysis is based on 353 permits implementing six local environmental plans in New Zealand, and on surveys of the developers who obtained the permits and of the planning agencies that granted the permits. The analysis finds that plan implementation is mainly driven by the resources of the planning agencies and by the quality of the plans, rather than by the characteristics of developers. Investments in plan writing and agency and staff capacity building thus improve the implementation of plans in the long‐run.     

Management of the zinc chain

In this study, a substance chain approach as a tool contributing to a sustainable development has been tested by applying it to zinc. An analysis of the western world zinc substance chain has been made in order to identify the main routes of zinc losses from the chain. Technologically feasible options to improve the management of the chain have been selected and applied to a modelled chain. With the emphasis on resource management, the model has been designed to evaluate the impact of options on the input of primary zinc into the chain. The consequences of the options for the energy resources have been analyzed.Redesigning the global zinc chain using the chosen technologically feasible options has lead to a lower primary zinc input when compared to the present chain, but a 45% primary zinc input is still needed, while the improved chain requires 8% less energy. To obtain a further decrease of primary zinc input in the chain, research should focus on emission abatement during zinc usage, where especially corrosion of galvanized steel forms a problem, and on the prevention of mixed-product waste streams with a low average zinc concentration. The energy analysis shows that options to improve the zinc chain should be carried out carefully, avoiding extra demands on the energy resources.The study indicates that designing a substance chain, along with even simple modelling, results in a good tool to calculate the impact of different kinds of options on the total chain.     

Translating a remediation technology into the required air,water, and rcra permits

Because remediation techniques and technologies are themselves generally viewed as contaminant source by hazardous waste laws and regulations, permits are required to use them, even if it is only to contain or remove a site's principal contaminants. Referring to such major environmental laws as the Clean Air Act, the Clean Water Act, RCRA, TSCA, and CERCLA, this article outlines the steps needed to translate cleanup projects into the appropriate permits.     

Natural history of crop-related wild species: Uses in pest habitat management

The natural histories of crop-related wild species in their native habitats can be used to develop novel pest management strategies. Traditionally, such information has provided insights for biological control, plant breeding, crop management, and applied ecology Further insights can be garnered.