Karachi Some unknown poisonous element Wednesday killed thousands of fish and other species at the Kenjhar Lake, one of the largest freshwater sources that supplies 70 per cent of drinking water to Karachi, the largest city in Pakistan.

The onslaught of fish, cows, and dogs which drank the water, was seen early yesterday morning. Even the seashells, which are found in the bed of the lake died and lifelessly floated on the lake surface and the shore, wildlife official and witnesses said.

"What I can see is that in the area of more than three kilometres all the living things in water have died including fish, other species and water plants," said Ghulam Rasool Khatri, the World Wildlife Fund representative in the Thatta district some 125 kilometres east of Karachi.

The lake, also known as Kalri Lake, is one of the largest freshwater lakes in Pakistan with extensive reedbeds and flowering plants of lotus. The lake breeds a diverse range of flora and fauna and a wide variety of waterfowl, thus it is a wildlife sanctuary.

"Even the plants and water has turned blackish," Khatri said as the lake offers a scenic look of blue water and a very famous among the picnickers from Karachi and nearby cities.

The reason for the sudden death of the water species is yet to be determined but Khatri, who reached the lake yesterday afternoon, said some rain water entered the lake after torrential rains in the area and the local villagers said with the arrvial of deadly rain water animals started dying.

‘Industrial waste'

"We have collected the sample of water and sent it for the laboratory tests to know the exact nature of the deadly element," Khatri told the Gulf News.

Environemnt Protection Agency (EPA) officials also reached the spot to examine and contain the damage.

However, he said rainwater that passed through the industrial wastage Nooriabad, Kotri and Jamshoro that could have fatally polluted the water. A company was also engaged in constructing a windmill.

A witness said he went to see the damage and found innumerable fish and other species floating dead on the surface in an area spanning four kilometres.

"I saw a big turtle lying dead on the surface as the bushes were also losing their freshness," Shahid Ahmad, a local resident said.

The incident has alarmed the residents of Karachi, who get their drinking water supply from the lake after it is filtered at two plants of Karachi Water and Sewage Board (KWSB), the water supply agency in Karachi.