Depositional profiles and relationships between organotin compounds in freshwater and estuarine sediment cores

A range of organotin compounds including tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) were measured in sediment cores collected from contaminated freshwater and estuarine sites in Essex and Suffolk, U.K. Butyltin compounds were found in significant quantities at depths of up to 60 cm within the sediments of marina and boatyard complexes with TBT concentrations ranging from <3 ng g^–1 (the detection limit) to >3000 ng g^–1. In general sediment TBT concentrations decreased with depth, but maximum enrichment tended to occur just below the surface. It was evident from these core profiles that the accumulation of organotins in surface deposits was on the decline and coincided approximately, with the implementation in 1987 of the UK retail ban on the sale of TBT based antifouling paints for application on vessels <25 m in length. The degradation rate for TBT in sediments was found to exhibit first order kinetics with half lives ranging from 0.9–5.2 years between different sites. Estimated degradation rates have also been determined for DBT and MBT. These ranged from 1.5–3.0 years for DBT and 1.8–3.7 years for MBT.     

Acclimatisation to nitrilotriacetic and in the activated sludge process

The period of acclimatisation prior to the biodegradation of nitrilotriacetic acid in an activated sludge pilot plant was studied in a series of experiments. The effects of low and high influent heavy metals concentrations upon acclimatisation are reported.     

The microbiological control of mine waste pollution

The removal of heavy metals and neutralisation of acidity in mine waste waters by algae and bacteria are reviewed. Algal growths in artificial meander systems have been shown to remove significant quantities of heavy metals and fine particulates from mine waste waters. Bacterial systems for the oxidation of ferrous iron and the reduction of sulphate leading to neutralisation of acidity are described. The use of bacterial extracellular polymers in the removal of heavy metals from solution is discussed with reference to its application to acid mine waters. It is concluded that a combination of bacterial and algal systems with process optimisation, including nutrient amendment, may provide suitable treatment for mine waste waters. Metal-resistant bacteria may also be important in reclamation, where it is possible that they can confer some degree of tolerance on the plants used to revegetate metal-contaminated tailings dumps.     

Green design tools for environmental management

Carnegie Mellon University's Green Design Initiative develops tools that environmental managers and decision makers can use to address real-world environmental issues. The initiative focuses on creating tools that are easy to use and that help companies prevent waste and pollution before they start.© 1999 John Wiley & Sons, Inc.     

Developing a sustainable energy strategy for a water utility. Part I: A review of the UK legislative framework

Increasing political effort to improve water quality across the UK and Europe has led to water and sewerage companies investing heavily in high-tech wastewater treatment plants capable of producing high quality effluents. Consequently, amounts of bought-in electricity used for wastewater treatment has and will continue to increase significantly over coming years, while greater provision of enhanced sewage treatment also produces greater volumes of sewage sludge requiring treatment and disposal. Over the same period, tougher controls on the quality of biosolids applied to agricultural land have also been introduced, while there has been an international attempt to reduce the use of fossil-fuel derived power sources because of concerns over global warming. The latter has brought about the introduction of financial instruments, such as the Climate Change Levy, to curb energy use, promote energy efficiency and encourage the development of renewable energy technologies. These factors are set to drive-up the costs of providing adequate sewage treatment services, while at the same time, a tough regulatory line taken to control profits on regional monopolies held by the UK water companies will significantly reduce their revenues over the period 2000-05. The result is that, financially, UK water and sewerage companies face their most challenging period since privatisation in 1989. This paper briefly outlines the current regulations relating to water quality and energy use that will affect water company operations over coming years.     

The importance of the short-term leaching dynamics of wood preservatives

The potential environmental impacts from the use of treated timber in aquatic areas is under scrutiny as a result of environmental legislation and reports of the deleterious environmental effects around treated structures. In this study leaching experiments of up to 3 weeks duration were conducted on two species of chromated copper arsenate treated timber, dried for different periods of time. Increased drying time significantly reduced leaching of Cr and As. The addition of a synthetic humic acid increased leaching of Cu and As, but reduced leaching of Cr. Putative risk assessments conducted using short-term copper leaching data suggested protocol design may influence decisions made regarding the environmental acceptability of such preservatives.     

The sex pheromone of the grain aphid,Sitobion avenae (Fab.) (Homoptera,Aphididae)

Summary The sex pheromone of the grain aphid,Sitobion avenae (Fab.), is identified as (4aS,7S,7aR)-nepetalactone, for which specific olfactory cells are located in the secondary rhinaria of the male antenna. The related (1R,4aS,7S,7aR)-nepetalactol was not produced by females in significant amounts (ca 10,000-fold less than the nepetalactone), although cells in the male antenna were found that responded specifically to this compound. Behavioural activity in the linear track ol-factometer showed attraction of males to the nepetalactone, but not to the nepetalactol.     

Supercritical water oxidation of phenol and process enhancement with in situ formed Fe2O3 nano catalyst

Environmental Science and Pollution Research - During the past few decades, the treatment of hazardous waste and toxic phenolic compounds has become a major issue in the pharmaceutical, gas/oil,...