| Sometimes during summer...we can get organic pollutants that can come in and do major damage." |
Children's Express journalists report on river pollution in the last of a four part series on the environment in Northern Ireland.
Pollution of our rivers is a serious environmental issue affecting plant, fish, wildlife and even humans if the river is a fresh water source.
Waste from industry and agriculture is the main culprit. Incidents can occur suddenly or the damage may build up over time. Organic farm wastes like silage and slurry (liquid manure) can contaminate rivers quickly, reducing the oxygen in the water resulting in major fish kills. Pesticide levels in water can rise slowly to critical levels.
Nitrate pollution in rivers is also common. This occurs when too much chemical fertiliser is applied to the land. The excess runs off and can find its way into drinking water sources via rivers and lakes. Too much nitrate accelerates plant and algae growth again leading to clogging, reduced light and oxygen levels.
Robert Wray, the District Inspector for the Foyle River, said:
"Both industrial and agricultural industry is policed. We go out on a routine basis to check what is going on, there are samples lifted from the water on an ongoing basis. They measure everything from organics right down to trace elements so we have a constant idea of what the quality of the river is."
Robert explained they are using new ways of assessing river pollution.
"We are starting to look at the invertebrates at the bed of the river for instance rather than taking a chemical sample. At best a chemical sample will give you a snapshot of what the quality of the water is where you are taking the sample, whereas organic pollutants will show up in invertebrates for three to four months, so they give you a better idea of what ongoing pollution is or background pollution is."
Although the River Foyle only suffers minor pollution problems there have been occasional major incidents.
"If we get a major fish kill, and there have not been too many, they can be industrial, where you have a toxic chemical entering the waterway that can do significant damage. Sometimes during the summer when the river is low we can get organic pollutants that can come in and do major damage because they reduce the levels of oxygen in the water and the fish would die.
"It very much depends on the nature of the pollution and what waterway it is entering, the smaller the waterway the less pollution they can cause. These happen on rare occasions. We could have a major instance tonight and we might not have one for a year."
About the team
This story was produced by Seamus McDermott 15, and Connor Kelly 14. It was published by the Belfast Telegraph and the Northwest Edition.
