-
Three of the water bottles the scientists purchased in Pretoria, or one-fourth of the brands they evaluated, were deemed unfit for human consumption.
-
The Sefako Makgatho Health Sciences University examined three types of water: mineral water, prepared water, and natural spring water.
-
All of them exceeded the World Health Organization’s recommended limits for chromium and nickel.
-
Three contained dangerous metal concentrations that were too high.
According to scientists who examined the brands of bottled water they found for sale in Pretoria shops, three of them are unsafe for human consumption. The other brands aren’t much better.
In all 12 brands examined at the Sefako Makgatho Health Sciences University in the city’s capital, levels of chromium and nickel were higher than those advised by the World Health Organization (WHO).
The highest concentration of manganese detected may also be harmful to human health, and half of the samples had lead levels above the WHO guideline.
According to a team from the biology department lead by Prof. Joshua Olowoyo, the information on the labels of some of the bottles did not correspond to the chemical composition of the water they contained.
The scientists write in the International Journal of Environmental Research and Public Health that a “hazard quotient” analysis “showed that the continuous consumption of some of the bottled water used in the study may pose a serious health risk to consumers.”
They demand the creation of a mechanism to track adherence to WHO guidelines and suggest that providers be required to make analytical results on water safety available to consumers.
Between April and June 2021, the researchers made a number of grocery store and spaza purchases. They brought dozens of bottles of “natural spring water,” “prepared water,” and “mineral water” back to their lab.
They blended three samples of each brand—which they refer to simply by the numbers one through twelve and do not name—and then used a spectrometer to analyze the resulting combinations.
The first unexpected finding was that, despite the labels’ claims of a pH range of 6.5 to a mildly alkaline 8.5, three of the samples “were all inside the acidic range with values ranging from 4.65 to 4.79″—far below the recommended range of 6.8 to 8.0.
According to Olowoyo’s team, this is crucial since low pH increases the solubility of trace metals. “This may raise their concentration in the drinking water, and our investigation suggests that this was the case.”
The next discovery was that all of the samples had chromium levels that were four to five times the WHO upper permissible limit.
The publication states that it “may be argued that part of the bottled water utilized in this investigation was a natural source from borehole water.” This is frequently the case, particularly with unregistered businesses, and the soil in the region where these bottled waters were bought is well known to be chromium-rich.
Although little absorbed by the body, chromium has been associated with kidney, liver, and lung cancer. An ore smelter’s significant chromium pollution of the drinking water in a rural Chinese research from 2011 revealed an increase in stomach cancer mortality there.
According to Olowoyo’s team, all the Pretoria water samples had nickel levels that were at least three times higher than those advised by the WHO. This was likely the result of underground water’s “prolonged and direct exposure to minerals,” though it could also have come from refineries, mines, and power plants.
“Nickel exposure can induce a number of negative effects on human health, such as allergies, cardiovascular and kidney illnesses, lung fibrosis, and lung and nasal cancer,” according to the US National Library of Medicine.
The WHO limit for lead, which typically enters water through corroded pipes but can also come from soil and other environmental sources, was surpassed by more than half of the samples.
The effects of lead intoxication on the neurological system are the key issue. and [premature birth], miscarriage, and premature death have all been linked to lead exposure during pregnancy, according to the study.
The levels of toxic trace metals present in three of the tested bottled waters, samples 6, 9, and 12, “may be considered unsafe for human consumption,” according to the study’s authors.
Statista reports that the average South African consumes just over 38 litres of bottled water per year. According to Olowoyo’s team, the perception that bottled water is pure and safe has led to its rapid commercial growth in both developing and developed nations.
According to scientific research, people prefer bottled water to municipal tap water because of its taste and perceived safety.
“However, given that South Africa has a wide range of mineral resources, including significant amounts of iron ore, platinum, manganese, chromium, copper, uranium, silver, beryllium, and titanium, the natural water may have been exposed to any of these minerals at levels above those that are safe for human consumption.
“A large number of mining enterprises contribute to South Africa’s GDP, yet the procedures used to extract these natural riches may also contaminate the groundwater.”
Iron, arsenic, titanium, vanadium, copper, zinc, molybdenum, and cadmium were also tested for in the samples by Olowoyo and colleagues Unathi Chiliza, Callies Selala, and Linda Macheka. The levels found were acceptable by WHO standards.