Ice on sale grossly contaminated with toxic metals, finds KU study.

KARACHI -- A study recently conducted by a team of Karachi University (KU) researchers showed that the ice being used to make different food items is heavily contaminated, particularly with some toxic, cancer-causing metals, and not fit for human consumption. The research was carried out at the KU's Institute Environmental Studies (IES).

The team collected 42 samples from all the six districts of Karachi and conducted analysis of different physicochemical parameters and heavy metals to check their quality.

According to the findings, all the ice samples were grossly contaminated with arsenic and lead and crossed the 0.01 mg/L limit set by the WHO. The maximum lead content (5.71 mg/L) was observed in the sample collected from Jamia Milia, Malir.

All samples failed to meet the 2011 WHO guidelines on nickel. The highest nickel level (2.55 mg/L) was observed in Muslimabad, Landhi. As many as 21.4 per cent samples had values greater than 1mg/L. The maximum allowable WHO limit set for nickel is 0.07mg/L.

The value of chromium fluctuated between 0.055mg/L and 0.93mg/L against the WHO value of 0.050.93mg/L.

A total of 28.57 per cent samples had sulphate levels above the WHO guidelines of 250 mg/L. The maximum sulphate concentration of 432mg/L was observed at Anda Mor in North Karachi.

The mean chloride value was found to be 96.271 mg/L.

Two ice samples collected from Gadap town and Shadman Town crossed the WHO guidelines (250 mg/L).

The minimum and maximum TDS (total dissolved solids) value was 512mg/L and 2451mg/L, which was found in the sample collected from Shadman Town. The WHO 2011 guidelines say that water TDS should be less than 1000 mg/L.

Chloride in water, according to the study, is considered to be safe at low concentration, but it could alter water taste at a concentration of above 250 mg/L.

Only two ice samples collected from Gadap Town and Shadman crossed the guidelines (250 mg/L).

A number of samples had hardness greater than 500mg/L set by the WHO. These samples were collected from Madras Chowk, Orangi Town 13, Gadap, Shadman Town and North Karachi.

Water hardness greater than 500 mg/L, the study says, would have adverse health effects on human health and may cause kidney stone formation and cardiovascular diseases.

The maximum hardness level was observed in Gadap town with a concentration of 1040mg/L.

All ice samples, however, had nitrate levels within the maximum allowable limit of 50 mg/L set by the WHO.

The team led by Dr Aamir...