Responses of <em>Selenastrum capricornutum</em>, <em>Eisenia fetida</em>, <em>Brassica nigra</em> and <em>Sorghum bicolor</em> to sent phone battery toxicity

Abstract

Indiscriminate release of spent phone battery in the environment poses a danger to human and animal life. Assessment of their toxicity using bioassays, therefore, becomes imperative. In this study, the Organization for Economic Co-Operation and Development (OECD) standardized toxicity tests exhibited a high degree of sensitivity in evaluating various endpoints across different trophic levels and taxonomic groups. These tests encompass a range of parameters, including mortality rate (h), growth inhibition (ECx), germination, and root length (ECx), providing a comprehensive assessment of spent phone battery toxicity. The responses of Selenastrum capricornutum, Eisenia fetida, Brassica nigra and Sorghum bicolor to spent phone battery toxicity were investigated. Standard methods of analysis for heavy metal, microalgal toxicity, earthworm mortality and phytotoxicity were adopted. S. capricornutum, B. nigra and S. bicolor seeds were exposed for 72 h and 5 d at concentrations ranging from 0 to 100 mg/L or mg/kg while Eisenia fetida exposed for 48 h and 14 d at concentrations ranging from 0 mg/L to 2.10 LC50 mg/kg for Gionee phone battery and 0 mg/L to 3.50 LC50 mg/kg for Lenovo battery samples. The result showed that all the spent phone battery samples (Gionee and Lenovo) had WHO and FEPA exceeded the limits of the heavy metals analyzed. The order of toxicity to S. capricornutum growth is Lenovo &gt; Gionee &gt; positive control K2Cr2O7 after 72 h exposure. On E. fetida, Gionee &gt; Lenovo after 48 h and 14th-day treatments while boric acid &gt; Gionee &gt; Lenovo as well as boric acid &gt; Lenovo &gt; Gionee were observed on B. nigra and S. bicolor, respectively after 5 d exposure. The responses of the model organisms in this study necessitate the establishment of stringent implemental management measures by government and environmental policymakers to effectively address the problems and challenges associated with e-waste.