Investigating the Toxicity and Edibility of Cocoyam Plant (Colocasia esculenta) in an Arsenic-Contaminated Soil

Abstract

The exposure of heavy metals such as mercury, cadmium, arsenic, chromium, thallium, and lead, and their interactions with soil and plants are of much concern due to their potential health effect. Phytoremdiation is one method used by plants to clean up soils contaminated with these heavy metals. Arsenic is a carcinogenic substance that thwarts plant growth and causes skin cancer in humans, among other health effects. Although arsenic decontamination by phytoremediation has been reported, the literature is silent about the toxicity and edibility of the plant after arsenic uptake. This study, therefore, assessed the toxicity of the Colocasia esculenta plant after using it as a phyto-sorbent for four weeks in a simulated arsenic-contaminated soil. The Bioaccumulation Factor (BAF) and the Translocation Factor (TF), calculated after the experiment, were 1.43 and 1.60 respectively indicating its hyper-accumulative property and high translocation of arsenic through the various parts. There was a decreasing trend of arsenic concentration in the solution samples across the weeks, and an accumulation of 58%, 28%, and 14% of arsenic in the stem, roots, and leaves of the plant respectively. The results showed that Colocasia esculenta is a good accumulator of arsenic from the soil. A comparison of the different arsenic levels recorded in the plant parts with standards, presents a great concern in consuming this plant exposed to an arsenic-contaminated environment. However, further studies should be conducted to ascertain the bioavailable state of arsenic in the plant parts after its uptake.