Toxicity of Spent Phone Batteries on Microflora in Marine, Brackish and Freshwater Ecosystems

Aim: To analyse and compare the effect of two products of spent phone batteries on bacteria (Pseudomonas sp.) and fungi (Mucor sp.) in marine, brackish and freshwater using standard toxicological bioassay.

Study Design: The study employs experimental design, statistical analysis of the data and interpretation.

Place and Duration of Study: Freshwater was collected from Biara and Marine samples were collected from Bodo City both of Gokana L.G.A, while brackish water sample was collected from Eagle Island, all in Rivers State, Nigeria. These samples were transported with ice pack to the Microbiology Laboratory of the Rivers State University, for analyses within 6 hours. While Spent phone batteries (product A and B) were obtained from the phone market, Garrison junction, Aba road, Port Harcourt.

Methodology: Toxicity testing procedures were carried out by preparing stock toxicant solution (four (4) grams of the spent phone battery content put into one hundred milliliter (100 ml) each of sterilized water samples separately), from which different concentrations (%); 0, 5, 25, 50 and 75, were made; each was inoculated with one milliliter (1 ml) of the test organisms (Pseudomonas sp. and Mucor sp.) in a separate set-up and tested for duration 0, 4, 8, 12, and 24 hours respectively using the spread plate techniques. The bacterial cultures were incubated at 37°C for 24 hours while fungal cultures were incubated for three (3) days at 35°C. The logarithms of total viable counts were used as a directory to determine the percentage survival and mortality. Median lethal concentration (LC50) was determined using the formulae; LC50 = LC100 - ∑ conc. Diff. × mean % mortality / % control. Data obtained were analyzed statistically using SPSS version 22.

Results: The results revealed that percentage logarithm survival of test organisms decreased with increasing exposure time and concentrations. The median lethal concentration (LC50) of the mobile phone batteries increases in the following order: (Note: the higher the LC50, the Lower the toxic effect) for Pseudomonas sp. Product B in freshwater (57.54%) < Product B in Brackish water (57.99%) < Product A in freshwater water (58.22%) < in brackish water (58.68%) < Product A in brackish water (58.88%) Product A in marine water (58.99%). While for Mucor sp.; Product A in freshwater (61.33%) < Product B in freshwater (61.55%) < Product B in brackish water (65.66%) < Product A in brackish water (71.88%)< Product A in marine water (71.88%) Product B in fresh water (74.22%).

Conclusion: The effect of Product B in fresh water is the most toxic having the lowest while Product A in marine has the lowest toxicity effect. These results show that if spent phone batteries are disposed into the aquatic environment, Pseudomonas sp will be more affected than the Mucor sp.