Published Thursday, 24 July 2014
In April, the Oona River, west of Dungannon, was also polluted. (© UTV)
Sixty fish have been found dead so far after the waterway was contaminated with farm effluent.
The environmental impact has been assessed as being of 'High Severity'.
A spokesperson for the Northern Ireland Environment Agency (NIEA) said that they received a report of pollution in the Bessbrook River, Co. Armagh on Wednesday afternoon.
"An NIEA Water Quality Inspector immediately visited the area to investigate the report and determine the environmental impact.
"The Inspector confirmed that the river was severely impacted with farm effluent, and his investigation identified the source of the pollution and ensured that it was immediately stopped.
"Further investigation revealed a fish kill had occurred. Statutory samples have been collected with a view to pursuing appropriate enforcement action, once the investigation is complete."
The spokesperson continued: "An initial count by Loughs Agency Officers revealed approximately 60 dead fish of a variety of species. Poor visibility in the water is hindering an accurate count; however the number of fatalities is expected to rise as the water clears."
A special Water Pollution Hotline - 0800 807060 - is available for members of the public concerned about river pollution in their area.
Last month, almost 400 fish were killed in the Glenavy River, Co Antrim.
Adult and juvenile trout died after the river was polluted by "an agricultural source."
Also in June, at Brantry Lough, near Dungannon, Co Tyrone a "significant number" of dead fish died. At the time, there was no evidence that a pollution incident was the cause.
Meanwhile, around 1,000 fish were killed in a major pollution incident in Co Tyrone in April.
The impact on water quality in the Oona River, which is west of Dungannon, was classed as "high severity" following the incident.
It is thought the majority of fish killed in the incident were brown trout.
© UTV News