Dumbor Kpalap’s scientific contributions

Three brands of spent mobile phone batteries (lithium-ion and Li-Polymer) were used as toxicant in freshwater sample with Aspergillus nidulans. The 24h Median Lethal Concentration (LC50) was used as indices for ecotoxicological assessment. Aspergillus nidulans survive and multiply in the Samsung contaminated freshwater with median lethal concentration (LC50 = 84.5659%) which is higher than the maximum toxicant concentration of 75%. Nokia (LC50 = 73.0401%) which is slightly lower than the maximum toxicant concentration showing that Aspergillus nidulans is slightly susceptible to the toxicant in fresh water. Tecno mobile phone battery is a Li-Polymer battery (LC50 of 66.3615%) which is lower than the maximum toxicant concentration showing that Aspergillus nidulans is susceptible to the toxicant in fresh water. Cumulative analysis of mean % mortality showed that Aspergillus nidulans is not susceptible to spent Samsung battery, slightly susceptible to spent Nokia battery and susceptible to spent Tecno phone battery. Mean % log mortality at different dose 0%, 5%, 15%, 25%, 50% and 75% revealed Samsung: 0, -5.618, 1.18, -1.87, -19.822, -17.042; Nokia: 0, 4.642, 3.974, -0.156, 4.018, 1.366; Tecno: 0, 4.59, 8.072, 4.458, 11.394, 17.23 [Note: the negative % log mortality values indicates growth above % control]. There were significant differences in the toxicants at 95% probability level; showing that Tecno battery is more toxic than Nokia and Samsung mobile phone battery. Samsung mobile phone battery might have been manufactured with green awareness. Spent mobile phone batteries should be handled as toxic materials that require special treatment. Implementation of a well-coordinated management strategy for spent batteries is urgently required to check the dissipation of large doses of toxic chemicals and rare heavy metals into the environment. However, the ability of Aspergillus nidulans to utilize battery chemical component for growth up to 45% concentration shows that this organism is a very potential tool for biodegradation of spent mobile phone batteries, thus industries concerned should mix broth cultures of Aspergillus nidulans with spent chemicals of phone batteries before discharge into the environment. It can also be used as a bio-marker to detect low and high level pollution in freshwater.