The devastating floods that hit Accra on Wednesday have swept an unauthorised refuse landfill into the Weija Lake, contaminating the drinking water source for about 80% of the capital's residents.
The illegal dumpsite, located along the banks of the River Jei at American Farm in Ngleshie Amanfro (Ga South Municipality), was created by an unknown property developer who filled the waterway for a commercial project. Tricycle waste collectors from Accra and beyond had been dumping municipal, industrial and e-waste there, residents say.
When the floods came, a large volume of plastic waste — including used sanitary pads, baby diapers and bottled water containers — floated into people's compounds. The stench attracted swarms of flies and mosquitoes. Residents now fear an outbreak of waterborne diseases.
Madam Helen Ankrah, Head Teacher of West Gate International School, about 100 metres from the dumpsite, said efforts to stop the dumping were met with threats and intimidation. She and other residents reported to the Ga South Environmental Office, which promised action but didn't do anything.
Mr Patrick Hayford, a resident, said the community had never experienced such a terrible flood. "The most disturbing part is how our compounds have been filled with all kinds of waste, a powerful stench, and a huge presence of houseflies and mosquitoes," he said.
Dr Naa Ayikailey Bruce-Vanderpuije, Senior Research Scientist at the Water Research Institute of Ghana, told myjoyonline that the waste likely released heavy metals like lead, cadmium, mercury, arsenic and chromium into the lake. Other contaminants include persistent organic pollutants such as PAHs from burnt waste and PCBs from electrical equipment, plus phthalates, BPA, faecal coliforms, E. coli, ammonia and hydrogen sulphide.
"Faecal bacteria and ammonia are relatively short-lived, but heavy metals don't degrade," she explained. "They partition into bottom sediments within days and can remain bioavailable for decades. PAHs and PCBs bind strongly to organic particles and can persist in sediments for years to over a century."
The most immediate danger is microbiological contamination. Faecal coliforms can cause acute gastroenteritis, typhoid, cholera and dysentery within hours to days. Ammonia spikes threaten aquatic life and can reduce disinfection efficacy.
Long-term risks are even more severe. Lead causes irreversible neurodevelopmental damage in children at any level. Cadmium accumulates in kidneys and causes progressive kidney disease. Arsenic is a known carcinogen linked to bladder, skin and lung cancers. PAHs and PCBs bioaccumulate in fish and pose cancer and endocrine disruption risks that will play out over decades if not fully remediated.
Dr Bruce-Vanderpuije urged the Ghana Water Company Limited and the Environmental Protection Agency to immediately test for total coliform, E. coli, turbidity, pH, dissolved oxygen, conductivity and ammonia. Within one week, a full heavy metal panel should be done. Within 2–4 weeks, screening for PAHs, PCBs, phthalates and bioassay toxicity testing should be completed, with sediment cores taken near the inlet. She insisted that all results be benchmarked against WHO drinking water guidelines and Ghana EPA/GSA standards, and published in full.
For the debris on the dam banks, she advised treating it as hazardous waste. Workers must use full PPE, and waste must not be burned openly as that creates dioxins and furans. Material should go to a permitted landfill with leachate containment, and a temporary silt curtain should be deployed to intercept particles during future rains.
Children under five face the greatest risk from lead, with even low levels causing irreversible harm.