KARACHI: A recent study has showed alarming concentrations of heavy metals, especially lead, arsenic and cadmium, in fresh fruit juices and milkshakes being sold in various part of the city. Prolonged consumption of such tainted food products carries risks of chronic toxicity that can potentially affect physical and mental growth, it says.

Titled Assessment of heavy metals in street-vended fresh fruit juices, Karachi, the research was conducted by Prof Moazzam Ali Khan and Dr Aamir Alamgir at Karachi University’s Institute of Environmental Studies (IES).Under the study, 80 samples of juices and milkshakes were collected in Saddar, Quaidabad, Gulshan-i-Iqbal, Orangi Town, Shah Faisal Colony, Korangi, Federal B Area, Sohrab Goth, North Nazimabad and Malir between 2017 and 2018. Samples of these beverages made from sugarcane, mango, banana, orange, apple and watermelon, with samples of milk and water used in their preparation, were tested for arsenic, cadmium, chromium, iron, lead, nickel and zinc. “What drew our attention towards this subject was the large-scale consumption of street vended fresh fruit juices and milkshakes, an economical source of nutrition,” said Dr Aamir Alamgir at the IES, adding that similar studies had been conducted in other parts of the country and they showed contamination in drinks.

High levels of lead, arsenic and cadmium found in samples collected in various parts of city

The most important findings of the research, he said, were high levels of lead, arsenic and cadmium in beverages. Citing WHO data, he said that exposure to these heavy metals in high concentration was linked to numerous diseases, including cancer. “For instance, children are particularly vulnerable to the toxic effects of lead and could suffer profound and permanent adverse health effects, particularly affecting the development of the brain and nervous system. “Long-term exposure to arsenic from drinking water and food can cause cancer and skin ailments. It has also been associated with cardiovascular diseases and diabetes,” he said.

Elaborating, he said that though there could be multiple sources of contamination, the study indicated that water and milk being used for preparing these beverages were the main source of contamination as their samples contained higher levels of heavy metals. “The presence of heavy metals in high concentration showed that water is contaminated with industrial waste and the milking animals are being fed fodder grown on water mixed with industrial waste,” he said, adding that contamination could also occur due to use of pesticides, unsafe fertilizer composition as well as use of polluted water and soil during crop cultivation. Some nutritionally important heavy metals such as iron, nickel, chromium and zinc are naturally found in fruits and vegetables in trace concentrations. Their presence in higher levels, however, posed serious threat to public health, he added. The WHO has set maximum permissible limits for toxic and essential heavy metals in the form of acceptable daily intake, for instance, lead (0.025 ppm) and arsenic (0.015 ppm). There are no WHO guidelines for iron, chromium, cadmium and nickel.

High levels of lead, arsenic

It found an alarming concentration of lead in sugarcane and watermelon juices; the minimum and maximum concentration of lead in sugarcane juices ranged between 6.64ppm and 8.652ppm with an average concentration of 7.858ppm whereas the minimum and maximum concentration of lead in watermelon juices ranged between 5.82ppm and 6.33ppm. “These values are crossing the maximum permissible limits for both fruit juices and water; 0.05ppm and 0.01ppm, respectively. The detected values of lead in fruit juices are extremely high as compared to the literature,” the study says. One source of contamination in sugarcane juice, according to the study, could be the oil used in cane machines for lubrication. The least amount of lead was detected in apple juices, though its value also exceeded the daily intake limit. All samples of beverages showed elevated concentrations of arsenic and exceeded the maximum permissible limit (0.01ppm) for water. “The available guidelines and results in this study indicate that the concentrations of arsenic found in juices have the potential to affect health in case of acute exposure. However, long-term exposure to arsenic in low concentrations may cause disruption in cellular communication, diabetes, vascular and lung diseases and cancer,” the study says.

The maximum value of arsenic was found in orange juice followed by mango milkshakes and apple juices. Levels of cadmium was found high in watermelon juices and mango milkshakes, but were either below detectable limits or not detected in other beverages. The highest mean value of chromium was found in mango milkshake and lowest in orange juice whereas its level was below detectable limits in apple juice. Lower concentrations of chromium were found in other juices. “The study shows alarming concentrations of lead, arsenic and cadmium in all samples, exceeding the guidelines for heavy metals in juices and water. Although, there is no guideline for iron, significant concentrations of iron were also found. “There is a toxicity risk due to exposure for a long period of time. Apart from milk and water, other sources of contamination could be low grade artificial colours and additives,” it says.

Published in Dawn, June 11th, 2018