Using river & lake invertebrates and other techniques to assess water quality in Britain and Ireland

The Loughs Agency undertakes river water sampling on a routine basis within the Foyle and Carlingford hydrological catchments. The biological and chemical monitoring of freshwaters assists in determining the concentration of harmful pollutants in the aquatic environment. This pollution monitoring has several key objectives:
1. to identify potential threats to fish health and aquatic ecosystems;
2. to inform the public about the quality of the aquatic environment and to raise public awareness of environmental issues;
3. to provide inputs into policy-making decisions;
4. to assess the efficacy of pollution control measures;
5. to identify trends in pollution and to identify future problems.

The following chemical parameters are analysed in the Loughs Agency laboratory:
• Ammonia (NH3)
• Total Phosphorus (PO4)
• Total Suspended Solids (TSS)
• Biochemical Oxygen Demand (BOD5)

Each of the 105 sites is sampled to assess for biological indicators using the 3 minute kick sampling method. A sample is obtained from the watercourse and stored in a plastic container for subsequent laboratory analysis. Staff at the laboratory then undertake detailed macro invertebrate identification and record the results for subsequent determination of a BMWP score to indicate the level of water quality.