Derg contamination highlighted

A NEW study of dissolved organic matter in Lough Derg, led by a Newmarket-on-Fergus environmental scientist, has indicated that contamination of the Nenagh River may be contributing significantly to the levels of agricultural waste in the lake.

Some of the scientists involved in the study have, however, stressed that further investigation is required to identify the source and to reach more definitive conclusions.
The study, which is part of a larger investigation involving research groups from Mississippi State University and Canada University of Toronto, hopes to contribute to the climate change debate by resolving missing links in nature’s carbon cycle.
Dr Brian Kelleher of Dublin City University, who is leading the international study, explained the group didn’t set out to look for contaminated compounds of natural organic matter but did find indications of agriculture pollution.
The former Newmarket and Clare minor hurler revealed that one of the potential discoveries from the study is a lot of the carbon compounds in the lake could be used as anti-cancer or as anti-bacterial pharmaceutical compounds.
He noted that there is as much carbon in water as the atmosphere and scientists are trying to learn more through their passage from freshwater to the sea.
Scientists discovered the main components of organic matter are very similar to what was examined in Canada and the United States and these compounds don’t change significantly.
According to the study, the main ingredients of carbon are fatty acids and lipids, which are stable and are difficult to break down.
Freshwater-dissolved organic matter is a complex mixture of chemical components that are central to many environmental processes, including carbon and nitrogen cycling but questions remain over its chemical characteristics, sources and transformation mechanisms.
The study, which was conducted over a 15-month period, sampled water from six sites at Lough Derg – Portumna, Williamstown, Dromineer, Hare Island, Coole Bay and Ballina/Killaloe. Sampling was carried out in August 2008 and January 2009 to assess temporal variation in dissolved organic matter.
The research, carried out by environmental scientists from Dublin City University and Limerick Institute of Technology, investigated the influence of the terrestrial surroundings on the lake’s dissolved organic carbon levels, which is invariably linked to man’s activities of urbanisation, farming and forestry in the region.
Dr David Sutton of the Limerick Institute of Technology said dissolved organic matter sampled at Dromineer Bay, the point at which the Nenagh River enters the lake, has been found to be indicative of pollution from farming activity. He explained however, that it might be a seasonal anomaly linked to spring/summertime agricultural practices or a one-off pollution incident, which the sampler happened to pick up at that particular time.
He acknowledged thought that it had caught the scientists’ interest and warranted further investigation.
He told The Clare Champion the scientists would like to be able to take further samples up the river to see where the concentration of pollution existed and to identify a possible source.
The study, which will be published early in the new year, suggests that the presence of zebra mussels might be influencing the delicate ecosystem of the lake to a point that new trends in the natural cycles are beginning to be established.
“The filtering activities of zebra mussels, whose numbers have risen significantly in Lough Derg since 1998, has been shown in several studies to have a large ecosystem-level influence on natural cycling of nutrients in the lake and this is most likely the case for Lough Derg also,” Dr Sutton noted.