Final report on the updating service on environmental chemicals in freshwater for the period 9.1.89 to 9.7.89

This report presents five batches of data which have been despatched to the Joint Research Centre, Ispra. The data as been allocated to various ECDIN (Environmental Chemicals Data and Information Network) files. The data comprises environmental chemicals in the freshwater environment, taking in paricular consideration: aquatic toxicity, bioaccumulation, metabolism and elimination biodegradation.

Bassenthwaite Lake: a general assessment of environmental and biological features and their susceptibility to change

Bassenthwaite (Lake) is one of the larger Cumbrian lakes, certainly one of the most distinctive, and of considerable conservation and amenity value. Although its shores lack sizeable settlements, its main inflow receives sewage effluent from a major tourist centre (Keswick) and is subject to episodic floods. These influences, the growing development of leisure activities at the lake (e.g. sailing, time-share units), and recent road-construction, have led to past appraisals of ecological impacts and lake management. The lake has not been the subject of intense and long-term ecological study, but much scattered information exists that is relevant to future management decisions. In the present Report, commissioned by North West Water, such information - published and unpublished - is surveyed. Especial attention is given to evidence bearing on susceptibility to change, affecting the lake environment and its biota or species of conservation interest. Extensive use has been made of the results of a recent (1986-7) seasonal survey by the FBA.

A general assessment of environmental and biological features of Windermere and their susceptibility to change

Bassenthwaite (Lake) is one of the larger Cumbrian lakes, certainly one of the most distinctive, and of considerable conservation and amenity value. Although its shores lack sizeable settlements, its main inflow receives sewage effluent from a major tourist centre (Keswick) and is subject to episodic floods. These influences, the growing development of leisure activities at the lake (e.g. sailing, time-share units), and recent road-construction, have led to past appraisals of ecological impacts and lake management. The lake has not been the subject of intense and long-term ecological study, but much scattered information exists that is relevant to future management decisions. In the present Report, commissioned by North West Water, such information - published and unpublished - is surveyed. Especial attention is given to evidence bearing on susceptibility to change, affecting the lake environment and its biota or species of conservation interest. Extensive use has been made of the results of a recent (1986-7) seasonal survey by the FBA.

Use of macroinvertebrate communities to detect environmental stress in running waters

This paper presents an account of some current uses of RIVPACS (River Invertebrate Prediction and Classification System), a software package developed by the Institute of Freshwater Ecology (UK). Background information is also given on the unique data-set on which the system is based. Before discussing RIVPACS, we consider the range of environmental stresses encountered in flowing-water systems and some of the ways in which stresses may affect macroinvertebrate communities. The wide application and relevance of the RIVPACS approach was recognised when it was chosen as the biological method for use throughout the UK in the 1990 River Quality Survey (RQS). In the concluding section we list some lessons learnt both from the 1990 survey and from our own testing exercise, and we outline current developments which will lead to a new version of RIVPACS for use in the 1995 RQS.

Microorganisms of the East African Great Lakes and their response to environmental changes

We have reviewed the phytoplankton composition and succession in the East African Great Lakes, their response to environmental changes, and the communities of microorganisms of the microbial food web. Recent studies in some great lakes, as well as progress in understanding phytoplankton succession and response to environmental factors, enable us to update knowledge of the phytoplankton ecology of these lakes. In particular, we present information indicating that phytoplankton composition in lakes Tanganyika and Kivu may reflect recent changes as a result of global warming or species introduction. We also stress the importance of microbes (at the base of the food web) in these systems and suggest that the microbial food web, which has been mostly overlooked until recently, may play a very large role in determining productivity and nutrient cycling in these large lakes.

Detection of cryptosporidium oocysts in water and environmental concentrates

Whilst current methods for the isolation and enumeration of Cryptosporidium spp. oocysts in water have provided some insight into their occurrence and significance, they are regarded as being inefficient, variable and time-consuming, with much of the interpretation being left to the expertise of the analyst. Two expectations of novel developments are to reduce the variability and subjectivity associated with the isolation and identification of oocysts. Flocculation, immunomagnetisable and flow cytometric techniques, for concentrating oocysts from water samples, should prove more reliable than current methods, whilst the development of more avid and specific monoclonal antibodies in conjunction with the use of nuclear fluorochromes will aid identification. Further insight into the viability, taxonomy, species identification, infectivity and virulence of the parasite should be forthcoming through the use of techniques such as the polymerase chain reaction, in situ hybridisation and non-uniform alternating current electrical fields. Such information is necessary in order to enable microbiologists, epidemiologists, engineers, utility operators and regulators to assess the safety of a water supply, with respect to Cryptosporidium contamination, more effectively.

The potential of RIVPACS for predicting the effects of environmental change

RIVPACS has been used successfully for biological assessment of river water quality but its potential in forecasting the effects of environmental change has not been investigated. This study has shown that it is possible to simulate faunal changes in response to environmental disturbance, provided that the disturbance directly involves the environmental variables used in RIVPACS predictions. These variables relate to channel shape, discharge and substratum. Many impacts, particularly those associated with pollution, will not affect these variables and therefore RIVPACS cannot simulate the effects of pollution. RIVPACS was sensitive only to major changes in substratum. It was concluded that, because of the static nature of RIVPACS, it cannot respond to the dynamic effects and processes associated with environmental disturbance. Thus RIVPACS, while showing direction of change and indicating sensitive taxa, cannot be used to predict or forecast the effects of environmental impacts.

Blue frontiers: managing the environmental costs of aquaculture

The report begins with an overview of the current status of world aquaculture. It then goes on to describe an approach for estimating the current combined biophysical resource demands of aquaculture for producer countries and regions. Following a comparison of these results with those available for other animal food production sectors the report then examines the consequences of likely future trends in production on the environmental impacts of aquaculture. Finally, the policy implications of the report’s findings are discussed along with the research agenda that should be pursued to meet the challenge of sustainable food production.

Environmental friendly aquaculture key to sustainable fish farming development in Nigeria

Aquaculture production in Nigeria has increased tremendously in recent times; along with this increase is the rise in the level of waste outputs from aquaculture practices. The discharge of waste from aquaculture operations on continuous basis leads to eutrophication and destruction of natural ecosystem in receiving water body. Controlled wastes production strategies is necessary to maintain sustainable aquaculture growth into the future, as long-term sustainability of fish culture systems depends on their ability to reduce their waste outputs. The release of solid wastes is mainly a function of the digestibility of various dietary components while the release of dissolved wastes is mainly a function of the metabolism of nutrients by the fish. This paper critically reviews the impacts of aquaculture wastes on the environment and the strategies to mitigate the effect of these impacts. Future trends and research needs on aquaculture induced effluents are outlined. As the amount of nutrient discharge is typically site and operation specific, effective farm management has been identified as the most important factor to avoid effluent pollution.