Scientists Call for Urgent Studies on Harmful Levels of Gender-Bending Chemicals in SA Water
BYLINE: TONY CARNIE
DURBAN: Scientists are worried that critical research on "gender-bending" chemicals in South African rivers and dams - including the Cape Town area - could be in jeopardy unless more money and public will are devoted to studying the problem.
Last year, a study by the Water Research Commission found potentially serious sex-ratio changes, deformities and other health problems in animals and fish in a nature reserve outside Pretoria.
These were linked to a cocktail of endocrine-disrupting chemicals, collectively known as EDCs.
In the Rietvlei Nature Reserve, researchers have found evidence of skewed sex ratios and birth defects in animals, fish and frogs, including "intersex" abnormalities, where fish showed evidence of male and female organs.
Studies at Cape Town sewerage works - Macassar, Zandvlei, Bellville - found high levels of the natural and synthetic female hormone estradiol. Though the levels were similar to those found in sewerage works in other countries, they were the first measurements done in South Africa.
Research in Limpopo has found evidence of decreased male fertility and genital damage in people linked to the use of the pesticide DDT in anti-malaria spraying campaigns.
A growing torrent of these natural and man-made chemicals is flushed daily into South African water systems, and several scientists are worried about the long-term health effects because EDCs can damage human endocrine systems at low concentrations.
Natural EDCs include male and female sex hormones that enter the water system in urine and faeces and which may not be removed during the water purification process, while synthetic EDCs include more than 4 000 chemicals such as DDT, along with a variety of pesticides, insecticides, plastics, heavy metals and other industrial softening agents.
According to a new research report on EDCs published by the Water Research Commission, these chemicals can lead to noticeable health damage at levels up to a million times lower than the known cancer-causing levels.
The latest report, edited by Water Research Commission consultant Anna Burger, synthesises the findings of several years of research - including suspected hot spots of EDC pollution such as the Jozini Dam and Makhatini Flats in KwaZulu-Natal, the Rietvlei Dam near Pretoria, the Hartbeesport Dam and Jukskei River near Johannesburg. …