BIOLOADS AND ENZYME ACTIVITIES OF PETROLEUM POLLUTED EFE RIVER WETLAND, UMULOLO, OKIGWE, IMO STATE. NIGERIA.

Abstract

The study investigated bioloads and enzyme activities of petroleum polluted Efe River wetland.
The bioloads and trend of enzymatic activities in petroleum polluted and unpolluted wetlands were
evaluated using standard methods. Bioloads for all microbial groups enumerated, had highest values
during rainy season when compared with dry season counterpart. Total viable count (TVC) had highest
counts in the lightly polluted wetlands – rainy/ dry seasons {(3.9 ±0.19) x 105
, (3.2 ±0.21) x 105},
followed by control “unpolluted wetlands” {(3.4 ±0.17) x 105
, (2.8 ±0.16) x 105} and lowest values in
the heavily polluted wetlands {(3.3 ±0.23) x 103
, (2.8 ±0.29) x 103} respectively. The same trend was
observed with other microbial groups assessed. Bacillus species was the most prevalent for both
seasons - lightly polluted wetlands – rainy/ dry season (87.5% ±0.11/ 75% ±0.16), heavily polluted
wetlands (50% ±0.32/ 25% ±0.15), and control “unpolluted wetlands” (75% ±0.14/ 62.5% ±0.24). The
values of soil enzymatic activities followed the same trend with bioloads. Dehydrogenase enzyme (µg
TPF g-1 hr-1
) activities recorded very high values (4658 ±57) in the assessed wetlands, unlike alkaline
phosphatase enzyme that had the least values (82.67 ±1.12). High values of enzymatic activities were
observed in lightly polluted wetland, followed by control (unpolluted wetland) and heavily polluted
wetland in that order. All values obtained in bioloads, prevalence and enzymatic activities, when
compared were statistically significant (p<0.05). This study has shown that petroleum on heavy
impaction could cause negative effects on wetlands bioloads and enzyme activities while light
impaction encourages bioloads replication and increased enzyme activities resulting in improved
indicator values.