A study conducted on vegetables grown with water from some selected urban areas of the Greater Accra Metropolis has revealed health risks for consumers due to the presence of mercury (a heavy metal) and faecal coliforms.
Published in April 2024, the study titled ‘Analysis of Heavy Metals and Pathogen Levels in Vegetables Cultivated Using Selected Water Bodies in Urban Areas of the Greater Accra Metropolitan Area (GAMA)’ focused on lettuce and bell pepper grown using open-surface wastewater from drains and constructed reservoirs in GAMA.
Using a mixed methods approach, researchers administered questionnaires to 67 vegetable farmers and collected vegetable samples from three urban farm sites – Haatso, Dzorwulu, and the Weija Irrigation Scheme site (WISS) – for laboratory analysis.
Heavy metal concentrations (lead, mercury, cadmium) were determined using atomic absorption spectroscopy after microwave digestion, while faecal coliform was quantified using the MacConkey-Endo broth method.
Results indicated that while lead and cadmium levels in lettuce were within the World Health Organization’s (WHO) permissible limits, mercury and faecal coliform levels exceeded the limits at all three sites.
The study emphasizes the need for increased education on the health risks of consuming vegetables from open-surface water sources and enforcement of phytosanitary standards to improve food safety and vegetable quality.
The use of polluted or contaminated wastewater sources for urban vegetable farming is common due to rapid urbanization and freshwater scarcity.
This practice raises concerns about agricultural produce quality and poses potential food safety and health risks for consumers in the Greater Accra Metropolitan Area, where the vegetable market is projected to grow significantly.