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Water Quality and Chemistry Workshops |
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SESSION LEADER – DAVID HYDES, CHALLENGER DIVISION, SOUTHAMPTON OCEANOGRAPHY CENTRE
Session leaders introduction
Four workshops were held to consider water quality issues, these were.-
The most obvious sign in the region of the effects of eutrophication is the extensive weed growth on the mud flats in the harbours. There is specific concern about the link between shell fish quality and how this may change with planned changes in sewage discharges into the Solent system. There is a general concern about the effects of anti-fouling agents on the biodiversity of the Solent ecosystems but there is a lack of specific knowledge for the different areas of the Solent. The maintenance of good bathing water quality is a cause for concern generally. Some of the potential problems in the Solent region are being addressed by changes in the location of sewage discharges. However, current practices of bathing water quality monitoring are suspect with regard to their ability to give the best indications of likely risk to both bathers and other water users.
A feeling expressed in all the workshops was a need for better linkage of the work being done by different groups (higher education institutes, Environment Agency, local, port, harbour and regional authorities). A suitable mechanism needs to be found to allow this to happen. The first thing is to increase awareness of what other people are doing. This could be done through an annual Solent Research Meeting that could be held in conjunction with the annual Solent Water Quality Conference. Better awareness could also be fostered by the setting up of a discussion group/bulletin board web page.
Main Issues
Within the terms of the Urban Waste Water Treatment Directive, Southampton Water is not an eutrophic environment. Levels of nutrients in the rivers are moderate for ones draining populated areas with intensive agriculture. Sewage discharges of phosphate and ammonia are greater than the river water inputs to the estuary. Dilution appears to be too rapid for significant de-oxygenation due to the nitrification of this ammonia to occur. Clear symptoms of eutrophication are present in the harbours (Langstone, Chichester and Portsmouth) in the form of the extensive beds of macro algae.
The Solent is a good place for basic research to help in the understanding of processes in eutrophic waters because of; the range of environments in the area; the work that has already been done and the potential to improve on the links that already exist between the various academic, agency and governments bodies working in the area.
Specific areas of concern are:-
Research Priorities
1. All the above topics need investigation. The critical areas of research are those which are relevant to the two current EU directives on "Nitrates" and "Urban Waste Water Treatment". Consideration must also be given to the requirements of the OSPARCOM strategy on the reduction of eutrophication.
2. Work in this area could be helped by better integration of those studies that are being carried out by the Environment Agency, University of Portsmouth, Southampton Oceanography Centre and Southampton Institute, etc.
3. As in many areas of environmental research, we would be able to understand the system much better if consistent long term records were available. There is a need for both the establishment of a readily accessible review of what is available, which could then be collated into a central database. At the same time, there is a need to establish monitoring which can provide pertinent and consistently collected information over periods of time allowing the identification of trends in eutrophication processes.
Management Priorities
The essential priority is the management of the system in line with the current EU directives.
Studies to be undertaken should include:-
Blooms
Nutrients
Other
A question which is being looked at world-wide is the degree to which the intensification of total biomass in blooms is associated with an increased risk of the enhancement of the abundance of toxic algal cells. Such events are thought to be related in some areas to changes in the ratios of the available nutrients, (nitrogen, phosphorus and silicon) as well as a simple increase in concentrations.
Main Issues
I. There are twin difficulties in both the identification of sources of shell fish for their assessment against hygiene criteria and the accurate gauging productivity which is estimated from records of landings. This is because the required information has to be recorded by the harvester, and small scale operations, which in total account for a large proportion of the catch, do not have to keep and return such records.
2. There is confusion regarding the relative roles of the Shellfish Waters Directive and the Shellfish Hygiene Directive. It might be better if the two directives where combined.
3. Proposed new regulations that are part of the EU Shell Fish Waters Directive, may be a driver for investment in the upgrading of the degree of sewage treatment that has to be applied before discharge or the relocation of discharges. A point that should be considered is the ‘cost benefit analysis' of the relative costs of improved sewage treatment, compared to any increase in the value of the shell fishery that would result from such work. Such discussion requires the collaboration of the interested parties: Environment Agency, Southern Water, local authorities, CEFAS and the shellfish industry.
4. There is a need to increase public knowledge and awareness, as only a limited amount of general information is currently available on water quality in shell fish areas.
5. There is generally a poor understanding of what the impacts of fishing practices such as trawling and oyster dredging are on benthic ecosystems.
Further research requirements
Management priorities
The monitoring of existing sewage improvements in order to provide additional information to enable better targeting of future investment.
Main Issues
Direct studies of the impact of pollution from anti-fouling material on the Solent ecosystem have been limited. There is some evidence from studies of Southampton Water bottom sediment that concentrations have decreased in recent years of trace elements such as copper (which have been used as anti-foulants).
Changes are likely in the near future, as the use of TBT on all vessels will cease in 2006 due to an International Maritime Organisation ban. At present, different regulations apply to leisure and commercial craft.
Desirable alternatives are regular defouling, the development of non-toxic fouling release surfaces, and possibly natural product based anti-fouling coating materials. Studies are required of the likely impact of interim alternative anti-fouling materials (e.g. Cu based, Irgarol). Research in these areas is being conducted locally at the University of Portsmouth.
Research Priorities
1. Within the Solent area there is a need to assess the impact that anti-fouling treatments may have had and may be having on marine bio-diversity. Sub-regions needs to be considered separately. Effects are likely to be small in the open waters of the Solent but may be greater in the container ports, naval harbours and enclosed marinas. The short term monitoring of environmental impact (including sub-lethal and synergistic effects) of existing and future anti-fouling materials needs to be considered; as does the long term fate of existing and future use of anti-fouling agents in the differing biogeochemical environments of the Solent.
Main Issues
Research Requirements
Management priorities
Source: Solent Science Conference, 21-22 September 1998
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