By Charles Saki
It’s cliché that water gives life or water is life. Water can be a cause of death under various conditions, some natural and otherwise. According to the Natural Resources Defence Council, “Water pollution occurs when harmful substances often chemicals or microorganisms contaminate a stream, river, lake, ocean, aquifer, or other body of water, degrading water quality and rendering it toxic to humans or the environment”, In 2015, 1.8 million deaths worldwide were due to water pollution according to a Lancet study.
Zimbabwe’s Cholera outbreak 2008-2009
Cholera is a very deadly disease that causes dehydration and can kill within a matter of hours. 2008-2009 marked the worst ever Cholera epidemic to hit the country in living memory. By the time the outbreak was over, 98,585 cases reported with more than 4,000 deaths.
What caused the outbreak?
Most deaths recorded in poor communities, with Budiriro and Glenview the hardest hit. Raw sewer effluent burst pipes flooded most streets, coupled at a time when intermittent water supply helped spread and fueling the epidemic. Community boreholes have got contaminated by raw sewage. At the time the Combined Harare Residents Association (CHRA) lobbied the government to return the management of sewer and water delivery to the city of Harare, claiming that Zimbabwe National Water Authority (ZINWA) had failed.
Ten years after the country’s worst cholera outbreak, another outbreak in 2018 hit the same areas again. The International Federation of Red Cross and Red Crescent Societies (IFRC)’s Maxwell Phiri said at the time, “The situation is incredibly complex. Most of the areas affected have already been dealing with an outbreak of typhoid. So, this is a double punch for them, and it shows the weakness of water systems even here in the capital. There is also a lot of movement of people between Harare and rural areas, and we’re very worried this could drive a very rapid spread of the disease.”
Zimbabwe Water Forum, a platform for Government and Development Partners to share international best practices in the water sector between Zimbabwe and other countries reported in policy note number 12 that, “Most surface water and some groundwater resources in Zimbabwe need to treatment before they can be safe for human consumption.” In 2017 tests conducted on borehole water quality in low-density areas and found that 95 percent contaminated with fecal matter. Many people in Harare rely on borehole water owing to the unavailability and lack of trust in municipal water. Contaminated boreholes in Budiriro and Glenview in 2008 were to blame for the Cholera outbreak.
In 2013 Harare’s department of water conducted investigations into borehole water quality for its 235 boreholes, of the 114 tested sites, 26 boreholes in High-density suburbs of Budiriro, Glenview, Hatcliffe, Warren Park, Tafara, Mabvuku, Dzivaresekwa, and Highfield were contaminated. May 2020 a borehole in Hatcliffe got decommissioned after a typhoid outbreak.
Lake chivero is among the world’s most polluted surface water reservoirs and is in a eutrophic state. Eutrophication occurs when surface water bodies become nutrient-dense, this then results in the formation of harmful algal blooms or blue-green algae.
“Phosphorus in the lake is mostly in the form of soluble orthophosphates – a form which is readily available for algal growth and consistent with the presence of sewage effluent.” Nhapi et al
Challenges for water treatment
The more polluted the water source, the more expensive and complex the treatment process without guaranteeing water quality.
Normally, eutrophic waters have to be extensively chlorinated, and high concentrations of chlorine and organic substances lead to significant concentrations of organo-chlorinated compounds in drinking water. These substances are potentially hazardous for human health; therefore, water for potable use should be protected from eutrophication.
The city of Harare currently uses up-to 9 chemicals and gobbling up to USD 3 million dollars every month to treat the water. Even after spending so much money, the water quality is still doubtful and no one outside council employment seems to trust the water coming out the taps. In some areas, residents have reported smelly and dirty water coming out of the taps.
In 2019, a South African water treatment Company, Nanotech Water Solutions conducted tests at Morton Jaffray waterworks which discovered the presence of harmful algae in treated water. Since the discovery, authorities seem to be not moved about the water quality in Harare either before or after treatment. No public inquiry or outcry after the test results showed the potential health risks in raw and treated water.
The results of the 2019 tests showed that the city of Harare’s treated water was contaminated with toxins from algal blooms, the city kept the information secret and has not publicly issued a statement to either deny or confirm the results even after media organizations tried to pry the information out of them.
According to the Nanotech “report” which DrynDirty has it’s possession, “various species of algae such as Anaebena sp., Mycrocystis Aeroginosa which are inherent in Lake Chivero and Manyame and have been isolated by a number of researchers such as Professor Magadza at the University of Zimbabwe (through funding from the City of Harare to the Hydrobiology Section at the University of Zimbabwe) and were also Identified during the demonstration”
Health risks associated with Harmful Algal blooms (HABs)
According to the U.S. Geological Survey, “Cyanobacterial toxins (cyanotoxins) have been implicated in human and animal illness and death in over fifty countries worldwide, including at least 35 the U.S. States. Human toxicoses associated with cyanotoxins have most commonly occurred after exposure through drinking water or recreational activities.”
Harmful Algal blooms are toxic to aquatic life, and to humans. Swimming or recreational use that necessitates contact with contaminated water is dangerous to one’s health. In humans, toxins have been linked to liver disease and neurological effects. The effects of long‐term, chronic exposure to cyanobacterial toxins are not yet understood; however, links between algal toxins and increased rates of liver cancer have been suggested (Grosse 2006).
Do not use toxin‐contaminated water for food crop irrigation.” Jennifer M. DeBruyn et al
Consistent with the Nanotech report, “Health effects of cyanotoxins can be acute or chronic and have been observed in the liver, nervous system, and gastrointestinal system.In studies, microcystins have rapidly concentrated in the livers of test animals, and at high doses, have resulted in organ damage, heart failure, and death. Long-term animal studies revealed chronic effects, including liver injury, renal damage, and an increased number of tumors” (Humpage et al. 2000).
The plant trial results were as follows:
1. 100% oxidation and/or removal of algae and associated toxins especially
hepatotoxins (i.e. toxins that affect the liver) and neurotoxins (i.e. toxins that affect the
central nervous system) by Chlorine Dioxide;
2. 100% removal of biofilms and associated algae in the Clarifier number 8, and
3. Consequently, the water clarity was visually and aesthetically improved.
The significance of the results are as follows:
1. Oxidation of algae particularly filamentous algae, which is not possible with the
current battery of chemicals. Chlorine Dioxide usage will lead to less Rapid Sand
Filter backwashes, longer filter run times, and consequently more water produced;
2. Removal of inherent biofilms in the Rapid Sand Filters and subsequently from the
Distribution Network will lead to the improved aesthetic quality of drinking water,
maintenance of free residual chlorine and reduced consumption of chlorine;
3. Oxidation of algae and its algal hepatotoxins and neurotoxins which have health effects on people and animals will lead to a significant reduction or total elimination of Powdered
Activated Carbon (PAC) as confirmed by the Chartered Institute of Water and
Environmental Management (CIWEM), London;
4. Oxidation of algae will enable improved effectiveness of the main coagulant Aluminium
Sulphate as this coagulant is not able to coagulate and settle live algae.
Poor water quality in Chivero affects recreational activities that bring revenue to those who operate from the lake. The death of fish and their contaminated state also destroys a very viable fishing industry which leads to loss of jobs. As people’s health is adversely impacted by pollution, more money will be spent on healthcare and less time spent on being productive due to ill health.
Pollution and bad water treatment regime are undoubtedly costing the city and the country millions of dollars without any significant improvement of the quality of water delivered to the residents. One can only wonder why that is.
As stated in the Nanotech proposal, “Nanotech’s service further offered in this proposal is to reduce the number of chemicals in use
from the current Eight (8) to around Two(2) or Three(3) and simultaneously reduce the costs by approximately 40% per month”
What to do
Alive to the fact that harmful algal blooms occur when freshwater is too rich with nutrients and it becomes a breeding ground for algae(Eutrophication). It is imperative that the government institute policies that promote water quality from catchment to up-to to the tap.
The World Health Organisation (WHO), has drinking water guidelines. According to the WHO guidelines, “the most effective means of consistently ensuring the safety of a drinking-water supply through the use of a comprehensive risk assessment and risk management approach that encompasses all steps in the water supply from catchment to consumer”
Lack of adequate policy and policing mechanism in Zimbabwe
Right to water guaranteed by the Constitution in section 77(a) which states that. “every person has the right to safe, clean, and potable water.” Without realigning laws to the constitution and implementation of strategies laid out in the WHO guidelines on drinking water safety, it will be very difficult for the country to ensure access to clean and potable water to its citizens by 2030
It’s been over 7 years since the National Water Policy but what it prescribed is yet to be implemented, one of the key issues is the establishment of a Water and Wastewater Services Regulatory Unit (WWSRU) which would be responsible for monitoring and ensuring water quality, pollution control being central to their mandate. This institution would have to be capacitated to ensure that WHO drinking water guidelines followed.
Once again, it is evident that Zimbabwe can make blueprints and craft good laws but fail dismally to implement them due to a lack of political will and a system that thrives on corruption and patronage.