Chennai’s water supply source contaminated by heavy metals

C Shivakumar
Chennai:

Industries located around Chembarambakkam lake are posing a threat to
the drinking water source of city with a study revealing heavy metal
concentration beyond permissible limits in the water body.



A study ‘ Assessment of heavy metal contamination in Chembarambakkam
lake water in Chennai’ which was published in Journal of Chemical and
Pharmaceutical recently states that heavy metal concentration of
cadmium, lead and Iron were observed in high concentration than the
World Health Organisation’s (WHO) recommended level in the water.



The study also stressed the need to take immediate steps to prevent
future contamination of the lake, which is one of the rain-fed
reservoirs from where water is drawn for supply to the metropolis. The
Adyar River also orginates from the lake..



The study, which was conducted by B Prabhu Dass Batvari and A
Surendran of Centre for Earth and Atmospheric Sciences, Satyabama
University in Chennai, focussed on three different locations of the
lake.



The water samples were collected and presence of Sodium, Pottasium and
Calcium were analysed with the help of flame photo meter, a device
used to determine the concentration of certain metal ions. The
presence of heavy metals including cadmium, chromium, lead, iron,
manganese, cobalt, nickle, zinc and copper were determined through
Atomic Absorption Spectrophometer, a procedure for the quantitative
determination of chemical elements using the absorption of optical
radiation (light) by free atoms in the gaseous state.



Interestingly, the samples revealed that the amount of Cadmium in
water was way beyond the permissible limit. As per world Health
Organisation, the permissible limit of Cadmium in drinking water is
0.003mg per litre. But the samples recorded 0.147mg per litres which
is way beyond the permissible limits.



As per United States Environmental protection Agency, if people
continue to drink water containing cadmium in excess of the maximum
contaminant levels (beyond 0.003mg/l), their kidneys could be damaged.



The study also revealed that concentrations of lead in water samples
ranged from 0.02 to 0.296 mg per litre. As per WHO standards it should
be 0.05 mg per litre.



WHO says that infants and children who drink water containing lead in
excess of the prescribed level could experience delays in their
physical or mental development. Children could show slight deficits in
attention span and learning abilities. Adults who drink this water
over many years could develop kidney problems or high blood pressure.
It also results in impaired renal function, hypertension, impaired
fertility and adverse pregnancy outcome, WHO states.



Interestingly, the keeper of Chembarambakkam lake is Water Resources
Department while the user of the lake is Chennai Metro Water. When
Express contacted WRD officials, they said that WRD would conduct
their own test to find out the presence of heavy metals. A Metro water
source said that the difficulty in maintaining the water body is that
there are two agencies involved in it. “If the ownership is given to
Chennai Metro Water, Chembarambakkam lake could be maintained well and
the issue of contamination due to heavy metals could be resolved,” the
source said.



Interestingly, the water body is also facing a threat from Chennai
Corporation’s move to set up a solid waste management (SWM) plant in
Kuthambakkam.



The proposed site for the SWM plant is a residential area and grazing
land and is one of the main water catchment areas, through which
around 31 cascade lakes overflow from Perambakkam to Chembarambakkam
lake. The move has also resulted in protest by residents.



Metal     permissible limit  Sample 1  Sample 2  Sample 3

Cadmium   0.03mg/l       0.152     0.187      0.147

Lead       0.05mg/l       0.296     0.057      0.02

Iron        0.03mg/l       0.4       0.284      0.208

Nickle      0.02 mg/l      0.084      0.03      0.038