Mutare - Cynthia Dzimbati was exhausted. Her three-month-old baby strapped to her back and panning dish in hand, she had spent the whole day working the Mutare River for not one single ounce of gold."This is now my life. I lost my job," said the 31-year old single mother, looking so worn out she could easily have passed for 50. "I have three children to feed."Dzimbati poured a few drops of mercury into a bowl of dirty water and stirred it with her bare hands.The gold in the river is growing more scarce these days, she said, so the illegal artisanal miners are relying on mercury, a highly toxic substance supplied by the smugglers who buy their product, to trap the precious metal from the muddy river waters in the eastern borders of Zimbabwe.Public health and environmental experts say the consequences are disastrous. Mercury is contaminating drinking water for miles around and causing neurological damage, especially to children.But Dzimbati and the roughly half a million illegal small-scale miners that a mining council estimates operate in Zimbabwe are desperate. Many agricultural jobs disappeared under President Robert Mugabe's land reform program launched in 2000 and the job market is shrinking.Pushed to the brink, women and children have joined the ranks of what once was a male domain, Wellington Takavarasha, president of the Zimbabwe Artisanal and Small-Scale for Sustainable Mining Council, told parliament in April. There are about 153 000 women and children now in the trade, he said.But gold prices have declined worldwide in recent years, and at the same time extracting the precious metal from the Mutare River has become harder.The mercury that miners use slowly attacks the nervous system. Ingested in small quantities each day it will accumulate in the body and eventually produce symptoms such as hair loss, memory impairment and loss of muscle coordination, according to health experts.Children are particularly vulnerable and foetal exposure can cause neuro-developmental problems.Child minersNadine Steckling, an international public health expert who has researched mercury use in Zimbabwe, estimates that artisanal gold miners use 25 tons of mercury annually.One of them is 13-year-old Trust Mutasa. He started panning for gold along the Imbeza River near Penhalonga at the age of 10, two years after he was orphaned. "I didn't know it's toxic. Next time I will be careful," he said with a disinterested air.Maxwell Teedzai, a Penhalonga resident, said the number of women and children in illegal gold mining has grown over the past five years."There are no jobs and children are not going to school. They are all coming here to earn a living," he said. "Women too have joined the bandwagon. The situation is really bad."Mothers cannot afford childcare and bring their small children to work, unaware of the risks from mercury exposure.Zimbabwe, which ranks in the world's top 10 countries using mercury in gold mining, is a signatory to the 2013 Minamata Convention on Mercury and is working towards ratification. The international treaty is designed to protect health and the environment from mercury and mercury compounds, including regulating artisanal and small-scale gold mining.A report by The Centre for Natural Resources Governance (CNRG), a Zimbabwe advocacy group, found that contaminated waste from illegal mining is polluting water supplies. It said nursing mothers tested for poisoning in the Kadoma area in central Zimbabwe had 25 times higher levels of mercury in their breast milk than is considered safe by the World Health Organization.CNRG Director Farai Maguwu urged Zimbabwe to tighten its controls on mercury imports and de-criminalize small-scale gold mining to enable better health and environmental controls.Most important, said Steckling, was to introduce a mercury-free method of mining. A pilot project in Kadoma using borax to separate the gold has proved successful, she said.Steady Kangata, spokesperson for Zimbabwe's Environmental Management Agency, said that while his agency controls mercury through a licensing process, once Zimbabwe ratifies the Minamata Convention it will provide a framework for national legislation to control the influx and use of mercury in gold mining."It will also prevent the possibility of Zimbabwe being a dumping ground of such hazardous substances," he said.