KARACHI: Samples of unbranded powdered milk recently analysed by a Karachi University (KU) team have been found to be contaminated with high concentration of lead.
According to experts, chronic exposure or short-term overexposure to lead carries serious health risks, especially for children.
The analysis, part of a study, was carried out at KU’s Institute of Environmental Studies (IES) by Prof Moazzam Ali Khan, Dr Aamir Alamgir and Hira Irshad.
Thirty three samples of dry milk were collected from Quaidabad, Nazimabad, Malir, Shah Faisal Colony, Saddar, Orangi, Korangi and Gulistan-i-Jauhar.
Often used in bakery items and teas, unbranded dry milk available at low rates all over the city is also considered a nutritional source for children by poor mothers.
The analysis showed that lead concentration ranged from 0.58ppm to 4.52ppm with mean concentration of 2.412ppm; the maximum allowable limits set by the Food and Agriculture Organization (FAO) and World Health Organization (WHO) for lead in food products is 0.1ppm.
“Lead was found in high concentrations in all samples, though few other metals were also detected. It indicates that the milk is contaminated, carrying serious health risks especially for children,” Dr Alamgir, an assistant professor at IES said, adding that the highest concentration of lead was detected in samples collected from Quaidabad (4.52ppm).
In the samples collected, concentration of chromium and iron ranged from 0.023ppm to 0.65ppm (mean value 0.184ppm) and 0.58ppm to 4.12ppm (mean concentration 1.959ppm) respectively. Cadmium was present only in six samples with mean concentration of 0.007ppm while arsenic was found only in four samples with average concentration of 0.003ppm. The concentration of nickel was below detectable limits in all samples.
According to FAO and WHO, maximum allowable limit in food products for nickel is 0.2ppm, 0.1ppm for arsenic, and 2ppm-5ppm for iron. There are no guidelines available for chromium in food.
On the source of contamination, Dr Alamgir explained that processes like heat treatment, homogenisation, vacuum evaporation, seeding and packaging were carried out during preparation (of dry milk) and metal contamination could occur at any of these stages, if substandard material was used or might be derived from contaminated raw milk.
It was also possible that the dry milk was prepared in unhygienic environment or prepared with chemicals.
“Workers we spoke to during our visits to packing units particularly in Quaidabad, Gol Market in Nazimabad and Jodia Bazaar in Saddar, were not willing to share much information and the environment they worked in was secretive. In fact, there was a security threat at some places as we felt that our movement was being closely watched,” Dr Alamgir recalled.
At one place, however, a worker did reveal that dry milk, either expired or rejected from factories, was also used in preparation as an ingredient. The team couldn’t visit a single dry milk processing unit and found the packaging process being done in small houses in areas like Quaidabad and Malir.
“It didn’t seem possible to visit processing units. However, I can say that contamination could also come through poor fodder and unsafe water used for raising cows and buffaloes, if the milk is indeed prepared with fresh milk.”
According to Dr Alamgir, lack of national guidelines on food products and absence of a monitoring and regulatory system particularly in Sindh have made public health quite vulnerable to disease.
“A lot of work needs to be done on how to regulate and monitor preparation and sale of food products, especially in Sindh. We haven’t seen any related activity here for a long time, though the Punjab government has taken a lot of interest in this serious public health issue,” he said.
According to the WHO, lead is a toxic metal whose widespread use has caused extensive environmental contamination and health problems in many parts of the world.
“It is a cumulative toxicant that affects multiple body systems, including the neurologic, hematologic, gastrointestinal, cardiovascular, and renal systems. “Children are particularly vulnerable to the neurotoxic effects of lead, and even relatively low levels of exposure can cause serious and in some cases irreversible neurological damage,” the WHO website says.