Cocktail of drug waste lurks in SA's tap water

27 September 2015 - 02:00 By PREGA GOVENDER

Consumers are unwittingly ingesting traces of antiretrovirals, anti-epileptic drugs, antibiotics and antidepressants contained in tap water. Compounds of some of these drugs have been picked up in several studies on water sources around South Africa between 2013 and June this year.At least two of these studies have found traces of carbamazepine, an anticonvulsant also used in the treatment of bipolar disorder, as well as tramadol, codeine and morphine, commonly found in painkillers.Scientists interviewed this week were adamant that the levels of these drugs found were well within limits set by the World Health Organisation, and that they were on a par with levels in the UK, US and Canada. But they agreed South Africa needed to monitor these rigidly to gain clarity on the long-term health implications of consuming low levels of these drugs.story_article_left1Dr Hugh Patterton, a chief researcher at Stellenbosch University, tested tap-ready water in Cape Town, Port Elizabeth, Durban, Pietermaritzburg, Johannesburg, Pretoria and Bloemfontein and found traces of carbamazepine as well residue of 15 other drugs.Titled "A survey of contaminants of emerging concern in drinking water in South Africa", the study is set to be published in the latest edition of the South African Journal of Science.Patterton concluded that the range of contaminants in drinking water warranted more regular screening as "we are only now becoming aware of the presence" of these chemicals .His study noted that some of the drugs found were designed to be physiologically active even at very low concentrations, making it crucial to investigate the long-term health impact.Pharmaceutical residue, he said, entered the water system from sewage, municipal and medical dumping sites and agricultural activities where antibiotics were used extensively."It's important to look at the prescription level of pharmaceuticals, especially those that are prescribed at much higher frequency than other compounds. It might also be that some of these compounds have long half-lives. For instance, carbamazepine might, once it is produced in the water, hang about for years."In addition, researchers from North-West University, who investigated the concentration of antiretrovirals in selected water sources, found the presence of nevirapine in five of the 31 drinking water samples tested.Increasing concern over the presence of contaminants in water prompted the Water Research Commission to meet stakeholders in July to develop a national research strategy to tackle the problem.Jennifer Molwantwa, research manager at the commission, said all users of pharmaceuticals "can be held liable for the presence of pharmaceuticals in the environment. There isn't a mechanism to take back unused medication from people, thus people may be disposing it in toilets, drains and bins."She said it was worth considering the high rate of antiretroviral treatment in South Africa, since drug residue that is not metabolised by the body could find its way into water sources.Professor Tiaan de Jager, deputy dean of research in the faculty of health sciences at the University of Pretoria, is involved in setting water-quality guidelines for endocrine disruptors in water.story_article_right2He said this involved developing a standardised testing and monitoring strategy that would have to be followed by water treatment plants, municipalities, industry and water users. His expertise includes environmental endocrine disrupting chemicals."Pharmaceuticals in the environment and the impact on health is a new focus with opportunities for senior postgraduate research. Pharmaceuticals are continuously screened, so more are being identified as potential endocrine-disrupting chemicals," De Jager said.In June, Edward Archer, a PhD student in Stellenbosch University's microbiology department, examined effluent water from a waste-water treatment plant in Johannesburg, and from a river that eventually flows into Rietvlei Dam.He, too, found the presence of carbamazepine as well as venlafaxine, tramadol, codeine and morphine.Said Archer: "Some compounds are not being well removed during the waste-water treatment process."He said only 10% of carbamazepine and less than 5% of the compound tramadol was removed. "Some pollutants are not effectively removed by conventional water-treatment processes. There is no legislation setting out how much of these compounds can be expelled into environmental waters."The chemicals were analysed at the University of Bath in the UK .And, he said, compounds such as carbamazepine, venlafaxine and tramadol were "at great enough concentrations" to pose a risk in the long term to animals living in the water and humans who were exposed to this water.Bettina Genthe, a senior researcher for water quality and human health at the Council for Scientific and Industrial Research, said a recommended priority list of chemicals of concern should include antiretrovirals, carbamazepine, antimalarial drugs and paracetamol.sub_head_start From the Vaal Dam, into your tea cup sub_head_endPharmaceutical residue in water is "a bit of a headache", not just in South Africa, but around the world.So says Karl Lubout, a water quality specialist with Rand Water, the biggest bulk supplier of water in the country.He said the utility used extensive purification processes, which included coagulation, flocculation, sedimentation, filtration, correction of the acid-alkaline balance and disinfection with chlorine and ammonia.Rand Water performs more than 250,000 analyses on water samples from more than 200 sample points such as rivers, dams and sewage discharges in the catchment area.In addition, it carries out more than 1.2million analyses every year at its purification plants and drinking water distribution network.Rand Water supplies an area of more than 18,000km², extending from Mabopane, north of Pretoria, to Heilbron in the south and from Bethal and Bronkhorstspruit in the east to Carletonville and Rustenburg in the west.Almost all of its water is surface water from the Vaal Dam which is supplied from the Vereeniging and Zuikerbosch purification plants 60km south of Johannesburg."We supply water to over 12million people in 17 local municipalities," said Lubout. He said the cost of producing good-quality water became "astronomical" if the raw, untreated water was polluted.sub_head_start A pharmaceutical smorgasbord sub_head_endDr Hugh Patterton collected samples from water treatment plants in all the major cities and found:• Carbamazepine, an anticonvulsant used in the treatment of bipolar disorder, was detected in more than 60% of the drinking water samples and its level was consistently high throughout the year in Bloemfontein;• Phenytoin, an anticonvulsant drug prescribed under the trademark Epanutin, was present in drinking water throughout the year;• Ephedrine, which is used as a decongestant and bronchodilator, was observed only in winter, consistent with its expected increased medical use.sub_head_start What lurks in our tap water? sub_head_endSouth Africa boasts high-quality tap water of world standard.This has been the case over many years.Water treatment plants and the treatment processes have been shown to be efficient, said the Department of Water Affairs in response to questions about research that has found traces of antiretrovirals, antibiotics, morphine and other compounds usually found in painkillers.“We are confident that most of the water treatment plants in the country are capable of producing water that is truly fit for consumption. The country’s Blue Drop certification process has also assisted a number of municipalities to up their game towards attaining such good standards.”The latest results in this regard will soon be made public by the minister. The department was pleased to note that the levels of contaminants referred to in the research were below dictated standards, and the Water Services Authorities and Water Boards take monitoring seriously.“This is so that we are able to retain and better the quality of drinking water especially.”

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