This study used the levels of pollutants and the histopathological
analysis of the gonads and liver of Sarotherodon melanotheron
sampled in Lake Nokoué and Lake Toho, both in Benin (West
Africa) to assess the health status of the ecosystems. Sixty adults
(30 males and 30 females) of this species were caught during the
flooding seasons from both Lake Nokoué, and Lake Toho (as a
reference). The physicochemical parameters of the water and the
heavy metal contents (Pb, Cd, Hg) in water/sediment/fish of three
sites (S1, S2, S3) in Lake Nokoué and two sites (S4, S5) in Lake
Toho were analysed. Results confirm very strong organic status
with organic pollution index ranging from 1.25 to 1.5. Pb, Cd, and
Hg levels in the water/sediment/fish muscle tissue of Lake Nokoué
were far exceeding international standards. The histopathology of
gonads revealed testis-ova up to 40% in males and follicular atretic
oocytes up to 33.33% in females, indicated oestrogenic effects from
the pollutants with a delay of spermatogenesis and stimulation of
oogenesis. The histopathology of the liver revealed the presence of
regressive changes. The findings call for actions to protect the
ecosystem from pollution and attention in terms of health of
humans consuming fish products from Lake Nokoué. |
University of Cape Coast