State DOE director Sharifah Zakiah Syed Sahab said the investigation was conducted following a Notification of Pollution Event (NPE) Level 1 at Sungai Kulim received by the department at 11am on Friday.

“The recorded reading for the ammoniacal nitrogen (NH3-N) parameter was 2.91152mg per litre (mg/L) which exceeds the limit. Following this, a team of investigators from the Kulim branch was deployed to trace the source of the pollution.

“A review of the inventory record and field investigations covering the upstream area of Sungai Kulim was conducted before the team found black-coloured water flowing from Sungai Air Merah, which is at the Kedah-Penang border, entering Sungai Kulim,” she said in a statement here today.

Sharifah said the investigating team then monitored the area using a drone along Sungai Air Merah.

“The drone detected the source of the black water discharge. It is believed to have originated from effluent or wastewater released from pig farming activities in Sungai Lembu.

“Inspections around the pig farming area revealed several ponds discharging effluent into Sungai Air Merah, which subsequently entered Sungai Kulim. The distance between the farming area and the confluence of Sungai Air Merah-Sungai Kulim is 3km,” she said.

She said the Toh Allang water treatment plant at Sungai Kulim (in Penang), which supplies water to Penang island, is about 7 km from the confluence of Sungai Kulim and Sungai Air Merah.

She said the results of the investigation have been conveyed to the Penang DOE for further action.