Pedogeochemical mobility of metals from fluorescent lamp waste and human health risk assessment.

Abstract

The management of fluorescent lamps wastes is a challenge, and its disposal in soils may cause harmful effects on human health and edaphic biota due to the presence of Hg and other potentially toxic metals. However, the pedogeochemical behavior of metals from fluorescent lamps is still rarely studied in the tropics. An Oxisol sample was contaminated in the laboratory using a dosage of 6.5% fluorescent lamp powder relative to the mass of soil. The mobility of metals was assessed through a sequential extraction protocol of the Community Bureau of Reference. To assess potential risks, a mathematical model of Human Health Risk Assessment was employed, based on human exposure on metal-contaminated groundwater from soil contamination. Evaluation of metal mobility showed that 6% of Ni and 30% of Cu in contaminated soil were in the potentially bioavailable fraction. The slightly acidic pH of the contaminated soil seems to influence the mobility of Ni and Cu. Zn and Pb were mainly found in the residual fraction, suggesting low geochemical availability. However, over time, metals may be leached, highlighting the importance of monitoring disposal areas. When these results are compared to the mobility profile found in extractions applied to pure fluorescent lamps waste, the data suggest that soil properties tend to reduce metal mobility. Human Health Risk Assessment showed significant risks associated with the human consumption of Cu-contaminated groundwater, considering a scenario of metal leaching from the soil. This study highlights the need for proper fluorescent lamps disposal in tropical terrestrial systems to prevent ecological and public health risks.