Mrs. Upile Mawenda

Mrs. Upile Mawenda

Co-author

Physics & Biochemical Sciences

6 publications

Upile Chitete-Mawenda is a self-driven, highly motivated and hardworking individual, who holds both a B.Sc. in Chemistry and M.Sc. in Applied Chemistry from the University of Malawi (UNIMA, formerly Chancellor College). As a JICA ABE Scholar, Upile studied at Sophia University and United Nations Uni...

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Human health risk assessment of microbial contamination and trace metals in water and soils of Chileka Township, Blantyre, Malawi

Journal Article
Published 4 months ago, 202 views
Author
Gunseyo Dickson Dzinjalamala
Co-authors
Assoc. Prof. Chikumbutso Chiziwa Kaonga, Mr. Fabiano Thulu, Mrs. Upile Mawenda
Abstract
This study assessed nutrients and microbial contamination in water and soil samples from Chileka Township, Blantyre
City, Malawi. Elevated total and fecal coliforms (1300 cfu/100 mL and 290 cfu/100 mL) in groundwater (GW), and
(34,000 cfu/100 mL and 8000 cfu/100 mL) in surface water (SW) were found, representing a risk of exposure to waterborne
disease. While the criteria in the Malawi Standard for raw groundwater was mostly met, water from only 20% of the
boreholes complied with the WHO requirements. Nitrate (
NO3
─) and Cl
─ (47.8 mg/L and 263 mg/L) exceeded the WHO
limits in GW. Cadmium (Cd) occurred in a few cases at concentrations up to 0.217 mg/L and 0.138 mg/L in GW and SW.
Lead (Pb) and Cr were below detection limits, while Mn (0.319 mg/L and 0.640 mg/L) in GW and SW, and Fe (6.92 mg/L)
in SW compromised taste. Though bacteriologically unfit for raw consumption by humans, both GW and SW chemically
met FAO-acceptable limits for irrigation, and standards for livestock watering. The NO3
─ and PO4
3─ maximum concentrations
in soil were 58.9 mg/kg and 506 mg/kg, respectively. Lead (Pb) and Cd were not detected whereas Cr, Zn, Cu, Mn
and Fe in soil were 27.7 mg/kg, 190 mg/kg, 60.4 mg/kg, 1307 mg/kg and 6552 mg/kg, respectively. Magnesium (Mg),
Ca, Na and K were 20,523 mg/kg, 22,334 mg/kg, 544 mg/kg and 5758 mg/kg, respectively in soil. The human health risk
assessment results, on the other hand, showed that at least 30% (6 out of 20) of the GW samples and 60% (3 out 8) of the
SW samples had HI > 1 for adults, children and infants, indicating existence of non-carcinogenic risk. Similarly, at least
15% (3 out 20) of the GW samples and 18% (1 out of 8) of the SW samples had CR > 0.001 for adults, children and infants,
suggesting a risk of developing cancer during a lifetime due to Cd exposure. Though both GW and SW are generally of
good chemical quality, chronic exposure to nitrate and cadmium is a health risk in the area. The current trace metal levels
are not worrisome, but soil nitrate and phosphate may need regular monitoring.
Year of Publication
2024
Journal Name
Discover Environment
Volume
2
Issue
62
Page Numbers
1-24
Supporting Files
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