Zimbabwe’s river system heavily polluted

Environment
Water is life, is a widely used catchphrase worldwide.

Water is life, is a widely used catchphrase worldwide.

Environment with Musapindira Mlambo

It is not surprising that water is regarded as precious because of the value that living organisms derive from it.

“A world without water is unthinkable. Water is the key to life. Without water there is no human, animal or plant life,” says a 2006 World Water Day statement on the Zimbabwe National Water Authority website.

Seven years later, the statement is still as relevant as ever.

Water is vital for both domestic and industrial purposes. It is an important commodity in human, plant and animal life such that any slight deterioration in its natural quality results in negative health and environmental impacts.

However, most of Zimbabwe’s river systems and dams are heavily polluted to the extent that they are now endangering both aquatic and human life.

Speaking during the launch of the Green Business Awards in Harare recently, Environmental Management Agency (EMA)’s director of ecosystems protection, Petronella Shoko lamented the contamination of the country’s water bodies as a result of poor waste management practices.

Shoko said effluent discharge into water bodies affected general water quality leading to negative health impacts.

Water pollution increases the costs of water treatment, especially in Harare where the council spends approximately US$3 million every month on nine chemicals to treat water.

Zimbabwe experienced a cholera epidemic in 2008 and 2009. Most of these cases were attributed to consumption of contaminated water and food.

Sadly, water provided by most local authorities in Zimbabwe is often muddy and unsafe to drink. This has led to growing scepticism and citizen mistrust on the quality of the water, with affording households preferring bottled water instead.

Unfortunately, this has exacerbated waste management challenges in the country, as bottled water consumers usually throw away the empty bottles after usage, or worse, burn them. Littering is another environmental ill plaguing the country at the moment.

The Zimbabwe Environment Outlook published in 2010 identifies sewage treatment plants, industries, agricultural activities and mining as the main sources of water pollution in the country.

These sources of water pollution are both point and non- point. Point source pollution occurs when the polluting substances are emitted from an identified source directly into the waterway, whereas non-point pollution is a result of underground spreading of pollutants from a large area into a waterway.

An example of non-point pollution is when agricultural chemicals such as pesticides are persistently used in excess, leading to the contamination of the soil. This further pollutes underground water.

Mining, a major source of water pollution

Mining is another major source of water pollution in the country. The release of metals such as zinc, copper, iron, cobalt and nickel into water sources contaminates the water.

The presence of iron in water, for example, has some detrimental effects on people’s health.

If consumed in excess, iron can result in severe stomach pains and the damaging of internal organs especially the brain and liver. Excessive intake of zinc in water leads to health complications such as neurological damage, anaemia, bone marrow failure and damage to the central nervous system.

In addition, the high exposure to nickel has some negative health effects such as skin rash, asthma-like reactions, bronchitis and poor lung function.

A significant number of mines in Zimbabwe use chemicals such as cyanide and mercury to process their minerals.

Cyanide and mercury are associated with a number of health effects such as kidney and brain damage, skin rashes, gene damage and failure of the central nervous system among other detrimental health failures.

Therefore, properly functional treatment plants should be constructed, where these chemicals would undergo a chemical degrading process to reduce their toxicity levels before disposing them in water bodies.

Zimbabweans should draw lessons from the Minamata mercury disaster in Japan in the 1970s, which resulted in the contamination of the whole Minamata bay by mercury, leading to the loss of fish and human life.

According to Douglas Allchin, mercury from the plastic production process at Chisso Corporation spilled into the Minamata bay with the heavy metal contaminating the food chain decades later.

This affected the whole community that depended largely on fish for their protein.

“The mercury not only poisoned individuals’ bodies, but also the community’s social relations,” wrote Allchin in a research paper titled The poisoning of Minamata.

‘LAKE CHIVERO ONE OF THE WORLD’S MOST POLLUTED LAKES’

In its Africa Environment Outlook, the United Nations Environment Programme noted that water quality in southern Africa has decreased because of pollution.

“Water quality is a growing problem particularly in urban areas and close to industrial centres,” reads the report.

The report also noted that Khami Dam in Bulawayo is one of the most heavily polluted dams in the country receiving about 700 cubic metres of effluent daily.

This ultimately results in water-borne diseases and creates problems for irrigation and industrial use.

Currently, Lake Chivero is ranked in the top 10 of the world’s most polluted lakes. The pollution is mainly as a result of disposal of raw sewage from Harare, Ruwa and Chitungwiza.

Various tests of samples taken from the lake have discovered high faecal content providing nutrients for the thriving of water weeds such as water hyacinth.

Feedback: [email protected] or [email protected] words)