KARACHI: A large number of samples of chicken feed and water collected from poultry markets and shops in the city were found contaminated with various heavy metals, a Karachi University (KU) study shows.

The study — Distribution & occurrence of heavy metals in poultry feed and water in Karachi — was conducted at KU’s Institute of Environmental Studies (IES) by Dr Aamir Alamgir, Prof Moazzam Ali Khan and Maiza Javed.

Samples of chicken feed and water given to birds for drinking were collected from various spots including Nazimabad, North Karachi, Nagan Chowrangi, Orangi Town, Gulistan-i-Jauhar, Saudabad, Liaquat Market, Khoso Goth, Malir Halt, Jinnah Square, Quaidabad, Korangi, Dawood Chowrangi, Landhi, Rehri Goth, Bagh-i-Korangi, Saddar, Shadman Town, Shah Faisal Colony and Green Town.

“We collected a total of 68 samples and found none free of contamination from heavy metals,” said Dr Alamgir, an assistant professor at the IES.

The ingredients used for preparing feed were possibly tainted with raw industrial waste

He added that the level of these metals in water and feed samples were compared with the guidelines of the World Health Organisation (WHO).

Sources of contamination

Asked about the sources of contamination, he explained that the presence of metals, especially lead, nickel and chromium, in chicken feed indicated that the ingredients used for preparing feed were possibly tainted with raw industrial waste.

“While there might be multiple sources of contamination, I did not find the findings surprising given the fact that we have been using our sea and even freshwater sources as gutter for all kinds of raw waste.

“I believe that this extremely harmful practice, which has played havoc with marine life, has contaminated the food chain,” he said, adding that small-sized fish and poultry waste were used as a protein source in raising chicken.

The second major contamination source, in his opinion, might be city’s water.

“Multiple studies have found city’s water unsafe for consumption. One important reason behind it is the mixing of sewerage lines with water lines at many places,” he said.

On health hazards posed by food contaminated with heavy metals, he said that studies had linked prolonged exposure and short-term overexposure to heavy metals to various illnesses including damage to lungs, kidneys, central nervous system, respiratory and cardiovascular systems and reproductive system.

Heavy metals in poultry feed

Ninety-one per cent of feed samples had lead values above the WHO 2011 guidelines (0.2mg/kg) whereas they all crossed safe limits for nickel. The maximum level of lead was found in the Quaidabad sample.

Samples collected from Shadman, Shah Faisal Colony and Malir contained lead within the guideline value.

Copper was observed above the guideline values in 67pc samples of poultry feed. Its maximum value was found in the sample collected from Nazimabad.

Eighty-two per cent of samples showed iron above the guideline value. Samples from Malir, Kala Board, Jinnah Square, Nazimabad and Shah Faisal (one sample) were within the safe limit.

Seventy-nine per cent samples had chromium concentration above the guideline limit (0.5mg/kg). Its highest concentration was found in Saddar.

All samples had nickel above the guideline limit.

Arsenic contamination was detected in samples collected from Jauhar Chowrangi, Saudabad, Liaquat Market, Malir RCD and Khoso Goth.

Water samples also tainted

All water samples had iron, lead and nickel above the WHO 2011 guidelines. Their highest concentration was recorded in Korangi, Saddar and Quaidabad, respectively.

Copper, however, was found within safe limits in all water samples. Fifty-five per cent of water samples were above the WHO guideline for chromium (0.05mg/L). The maximum concentration of chromium was found in the Dawood Chowrangi sample.

According to the study, arsenic in water is a major concern in Pakistan because it is also found naturally in water reservoirs and can originate from pollution by industrial activities or specific feed additives.

Thirty-four per cent of all samples had arsenic values above the WHO guideline and the highest arsenic concentration was found in Korangi 2 1/2.

Last year, a study published in the International Journal of Community Health Sciences had found samples of lentils, potatoes and chicken meat brought from the open market in Karachi, both in raw and cooked form, tainted with metals known to cause human poisoning.

The study was conducted by the department of community health sciences at the Aga Khan University in collaboration with the department of environmental and preventive medicine of Jichi Medical University in Japan.

The chicken meat was uniformly contaminated with high arsenic levels irrespective of the utensil material used for cooking.

Published in Dawn, April 2nd, 2019