Zimbabwe's cities are the biggest polluters, poisoning rivers and dams with germ-laden sewage, with industrialists cheating over their waste and small-scale miners dumping the worst poison -- mercury -- coming up fast behind.
The cities have overloaded, undersized and poorly maintained sewage plants, with Harare in the worst position since its main water reservoirs are downstream of its sewage works.
Industrialists are supposed to follow national and municipal rules and regulations. Some do: some don't. And the ones who don't can dump some dangerous chemicals.
Small-scale miners release 80 tonnes of mercury a year into the environment according to University of Zimbabwe consultants, plus other poisons, and large-scale miners can be careless with the low levels of enforcement.
The Zimbabwe National Water Authority (Zinwa), the body that manages the country's water resources says nationwide, council water sources are the most polluted, with its parent ministry, Lands, Agriculture, Water, Climate and Rural Settlements defining water pollution as "the introduction of substances that are dangerous to human health, harmful to living organisms and ecosystems".
Zinwa public relations manager Mrs Marjorie Munyonga said among the most polluted water bodies are Lake Chivero south-west of Harare, Khami and Umguza dams outside Bulawayo, Odzi and Dora Rivers in Mutare, and Darwendale and Biri dams to the west of greater Harare.
In Harare, the Environmental Management Agency (EMA) recently sampled 24 points located along streams and rivers, including four that drain Harare city and its satellites: the Manyame, Mukuvisi, Marimba and Ruwa.
Water in all four ends up in Lake Chivero, although for Ruwa, the water passes through two smaller dams.
EMA Harare provincial environmental education and publicity officer Ms Batsirai Sibanda attributed the Lake Chivero pollution to discharge from sewage treatment facilities and industrial discharge .
"The major polluter of Lake Chivero is City of Harare, caused by the local authority's sewage treatment plants.
"These plants are partially functional, failing to meet requirements.
"Due to urbanisation and lack of new treatment plants being constructed, they are receiving raw effluent higher than the stipulated capacity. Some of the challenges being faced by these plants include power shortages and maintenance for their machines," she said.
Ironically, Harare is shooting itself in the foot as it draws its water from Lake Chivero, requiring US$2,5 million of chemicals monthly instead of using less than US$1 million to get drinking water.
City of Harare and Ruwa Local Board have since been taken to court for raw sewage discharge into the environment.
Kariba Municipality was also fined $2 000 for discharging raw effluent into streams and the environment after EMA took the council to court for contravening Section 57 of the Environmental Management Act; illegally discharging raw sewage into the environment.
According to information from EMA, an inspection was carried out in Nyamhunga on April 27, 2018, where it was observed that the municipality was discharging raw sewage into a Kariba Dam tributary.
Ms Sibanda said the other possible source of pollution in water bodies were sewer bursts that are very rampant, especially in Harare and Chitungwiza due to dilapidated sewer infrastructure and overloading above design capacity.
"Industry also contributes to the pollution of Lake Chivero.
"There are reported incidents where industry does not comply with municipal regulations of discharging their pre-treated effluent into municipal sewer lines, but they discharge directly into streams and rivers that feed into the lake," she said.
Community Water Alliance Programmes Manager Hardlife Mudzingwa said studies have shown that in five years, people consuming fish from the polluted Lakes like Chivero risk having cancer.
"EMA should introduce hefty fines to councils and industrialists discharging raw effluent sewage as the current charges are way too low such that organisations may see it more cost effective to pay the fine than to treat their emissions," he said.
He also wished Harare could draw water from upstream of the city, but even the largest proposed new dam, Kunzvi, is only a third the size of Lake Chviero and so will not make a lot of difference to the total raw water supplies.
The only solution will be to enforce laws so that Chivero water is clean.
EMA does regular checks of the quality of water along Marimba and Mukuvisi rivers.
It monitors through the collection of water samples from these rivers once every month, and the samples are analysed at a laboratory.
If there is any pollution taking place along rivers, the agency identifies the sources of pollution and orders them to rectify the situation within 24 hours.
Zimbabwe Environmental Lawyers Association recently raised a red flag over the pollution of the Save and Odzi River by diamond mining companies operating in Marange area in Manicaland, which has continued to affect and destroy sources of livelihoods for poor and vulnerable households and villagers that live near and rely on the two rivers in Chimanimani, Chipinge, Marange and Buhera.
The alleged principal offenders were Diamond Mining Company, Marange Resources and Anjin Investments.
A lot of villagers have lost livestock which died after drinking mine effluent.
Gardening and irrigation schemes have also been affected, while the ecosystem has been significantly compromised.
The small-scale gold mining activities were rampant in Mazowe, Bindura, Kadoma, Kwekwe, Shurugwi, Chinhoyi and Mutoko where river banks were being polluted at unprecedented levels.
The report did not, however, disclose the actual extent of the level of pollution, but it is beyond doubt that the levels are bad.
WHO considers mercury as one of the top 10 chemicals of major public health concern.
It affects aquatic life because it pollutes water and stays in it for a long time, affecting fish, which when consumed can affect the whole food chain.
Small-scale miners use mercury to refine gold, separating gold from ore, and it is a highly-poisonous element which can affect the brain, nervous and reproductive systems if inhaled as vapour.
While Government is yet to find a replacement for mercury, which is finding its way into water bodies, EMA, through holding awareness campaigns and workshops with small-scale miners, has since stepped up efforts to reduce the use of mercury, with a long-term plan of eliminating, as well as substituting the substance.