Toxicological Bioassay of Petroleum Products (Kerosene) in Tri-aquatic Ecosystem Using Pollution Bio-monitor Pseudomonas sp

The toxicological bioassay of petroleum products (industrial and local ‘kpo-fire’ refined Kerosene) in
tri-aquatic ecosystem (marine, brackish and freshwater) using pollution bio-monitor Pseudomonas sp.
were investigated. The study employs experimental examination and statistical analysis of data and
interpretation. It was designed to evaluate the different kerosene concentration and the duration of
exposure that could cause potential toxicological effect on Pseudomonas sp. in tri-aquatic ecosystem
which was used as indices to access level of pollution. Standard microbiological techniques were
used; toxicity procedure were applied using local and industrial refined kerosene; prepared at
concentrations of 1.625%, 3.25%, 6.5%, 12.5% and 25% in fresh, brackish and marine water; total of
36 different microcosms. These were tested with Pseudomonas sp. for 0, 4, 8, 12 and 24 h separately
for each toxicant. The cultures were incubated at 35°C for 24 hours. The median lethal concentration
(LC50) was employed to compute the toxicities of the different toxicants on the test organism. The
results specify that percentage (%) logarithm of mortality of Pseudomonas sp. increases with
increased toxicants concentration and exposure time. The pollution bio-monitor Pseudomonas sp.
demonstrated sensitivity to the toxicity of local and industrially refined kerosene. The sensitivity
showed variations, toxic level decreased in the following order (noting that the lower the LC50, the
more toxic the toxicants): Industrial refined kerosene in fresh water (18.79%) > Industrial refined
kerosene in brackish water (20.81%) > Local refined kerosene in brackish water (21.47%) > Industrial
refined kerosene in marine water (22.66%) > Local refined kerosene > (24.25) > Local refined
kerosene in marine water (24.94%). Using the Pollution/Toxicity Bio-monitoring evaluation Chart;
Local refined kerosene in marine, brackish and freshwater were ‘Toxic [High], Industrial refined
kerosene in marine water was ‘Toxic [High]’ while Industrial refined kerosene in brackish and
freshwater were ‘Toxic [very High]’.
Conclusion: The study showed that industrial refined kerosene in fresh water (LC50 = 18.8%) has
the highest toxicity strength while local refined kerosene in marine water (LC50 = 24.92%) has the
least toxicity strength on Pseudomonas sp. in the tri-aquatic ecosystem. These results show that local
and industrial refined kerosene can inhibit the growth of Pseudomonas sp. in an aquatic
ecosystem; noting that Pseudomonas sp. is one of the most effective biodegrading bacteria in
ecological biogeochemical cycles, pollutant removal/remediation and a key pollution bio-monitoring.
Pseudomonas sp. tolerance for hydrocarbon and its initial sensitivity per mortality within 24
hours of exposure could be accessed as indices to measure level of pollution or toxicity of petroleum
products.