Abstract:
This study was conducted from August 2008 to May 2009 in Mwanza (Tanzania), Jinja
(Uganda) and Kisumu, Homabay and Suba (Kenya) to establish the sources of pollutants
in particular endocrine disruptors and microbial pathogens in water and fish. A sociological
study was undertaken using qualitative and quantitative methods. Microbial contamination of
water and fish in the lake was assessed in 14 water and 60 fish samples in Mwanza. In Jinja,
assessment of microbial contamination was carried out in 100 water and 26 fish samples. A
total of 80 Nile tilapia were collected from Kisumu, Homabay and Suba and examined for
gross pathological lesions using standard necropsy techniques. Findings from the sociological
studies indicated that, the knowledge and awareness on endocrine disruptors in the region is
low. Pollutants that find access into the lake and have potential for disrupting the endocrine
systems exist in all cities and originate from point and non-point sources. Human, industrial,
agricultural, hospital and domestic wastes are the main sources of pollutants likely to contain
endocrine disruptors. These pollutants are handled poorly and most of them are disposed off
into the lake without treatment. In Mwanza, contamination of water with faecal material at
various landing sites was observed in 85.7%, 78.6% and 35.7% of the samples determined
using Total Viable Counts, Total Coliform Counts and Total Faecal Coliform Count. All
water samples were negative for Salmonella spp, Vibrio spp, Cryptosporidia spp and Giardia
spp. In Jinja, microbial contamination was observed in all sampling sites as determined by
aerobic plate count (APC), Total Coliform Count (TCC) and Escherichia coli count. There
was no significant difference in microbial load between sampling sites (P > 0.05). The gross
pathological lesions were generalized hyperemia, liver changes (paleness, grey spots and
hemorrhages), cystic urinary bladder, atrophied testis and kidneys, eye opacity, degenerated
ovaries, grey patches on the stomach, clear cysts in the testis, deformed dorsal fin and ulcers
on the lateral side of the body. Further studies are underway to confirm the likely causes of the
observed lesions and the impact of the observed pollutants and microbial pathogens.
