PETALING JAYA - Several disused mining pools at Bestari Jaya still show signs of heavy metal pollution and are unsuitable as an alternative water supply, says a geologist from Universiti Malaya.
Following a study visit with several students to the site in Kuala Selangor two weeks ago, Dr Muhammad Aqeel Ashraf said some of the mining pools observed were unsafe for use as alternative water supply.
"Most of the 108 mining pools in the area are safe to be used as an alternative source of water, but several of them have a green-coloured hue, which is a sign for a number of metal elements in the water," he said when contacted yesterday.
The affected pools were usually the deep ones, measuring between 30 and 40 metres, he added.
Dr Muhammad Aqeel said there was also a high risk of polluted sediments entering the disused mining pools with heavy sand mining.
"The overall area is very big and chances of pollution from former and current mining activities remain high."
Dr Muhammad Aqeel conducted a study in the area in 2010 for his doctorate titled Study of Water Quality and Heavy Metals in Soil & Water of Ex-Mining Area Bestari Jaya, Peninsular Malaysia along with fellow researchers at UM's chemistry and geology departments.
The study suggested that the physio-chemical and metal content in the area exceeded permissible limits set by Malaysian Water Quality Standards.
The study reported that the level of degradation in the water quality and severe heavy metal pollution in the Bestari Jaya mining ponds was a major environmental challenge to the ecosystem and posed a potential source of pollution to Sungai Selangor, the end recipient.
In light of yesterday's announcement on the lifting of the water rationing exercise, Selangor Mentri Besar Tan Sri Abdul Khalid Ibrahim gave his assurance that mining pool water was safe.
"The mining pools have been identified as alternative water sources by the Selangor Water Management Authority since 2009," he said.
Meanwhile, Coalition Against the Privatisation of Water coordinator Charles Santiago said the state government should produce a letter from the Chemistry Department and the Health Ministry stating that the mining pool water was not contaminated before dumping it into Sungai Selangor.
"The letters must state that the pool water does not contain arsenic, zinc, tin and other heavy metal residue which has serious health implications," said Santiago, who is also Klang MP.
He added that the treatment plants were not equipped to treat water containing heavy metal residue.
He said unlike the practice in other counties, the mining pools here were not treated and rehabilitated when they became redundant.