Harvalem turbidity raises concern

PANJIM, AUG 26
If you are planning an outing to the Harvalem waterfalls, close to Sanquelim, this weekend, chances are you may be greeted by turbid waters, a phenomenon considered normal in the rainy season.
However, the Goa State Pollution Control Board that sampled the water for testing after the issue was tabled in the Monsoon Session of the State Assembly by Mayem MLA Anant Shet feels the turbidity is a bit too high.
The Board measured 10 parameters – including pH, conductivity, turbidity, metal iron, manganese, chemical oxygen demand (COD), bio-chemical oxygen demand (BOD) and nitrite – of water samples collected upstream and downstream of the picturesque waterfall, which comes alive in the monsoon season.
Chairman of the Board Simon D’Souza said there is a strong possibility that the mining run-offs upstream may be responsible for this phenomenon due to heavy rains. “We consider the turbidity is high but there are no specific standards set against which it could be measured to come to a final conclusion.”
Reading out from an analysis report, D’Souza said the turbidity was found to be 205 NTU (nephelometric turbidity units) upstream and 182 NTU downstream.
The chairman said the iron content was also on the upper side at 5.9 mg/l (milligrams per litre) downstream, while upstream it recorded 5.4 mg/l.
Environmentalists have reiterated that silt from more than a dozen mines, legal and illegal, operating in the area was killing the waterfall.
Besides, high turbidity and iron content, the pH of the water at 5.55 was found to be low indicating acidic nature. Downstream the BOD was high at 3.5 mg/l when the maximum limit is 3 mg/l. This means there is presence of organic matter like sewage, D’Souza stated.
Over a question on his conclusion into the analysis of report, the chairman said it was very difficult to infer on the same. “We have classified the water into class ‘C’ which means it can be used for drinking after treatment,” he said.
However, citing the high turbidity, environmentalists have once again questioned government’s seriousness in curbing illegal mining upstream of the waterfall.