Health risk assessment of potentially toxic elements (PTEs) concentrations in soil and fruits of selected perennial economic trees growing naturally in the vicinity of the abandoned mining ponds in Kuba, Bokkos Local Government Area (LGA) Plateau State, Nigeria.

This study was designed to determine the level of potentially toxic elements (PTEs) contamination in soil and selected fruits and assesses the health risk of inhabitants in the abandoned tin mining community in Kuba, Bokkos LGA. Samples of the abandoned mine soil and selected fruits mango (Magnifera indica), guava (Psidium guajava), avocado pear (Persea americana), and banana (Musa spp)) from the vicinity of the abandoned mine were analyzed for the presence of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) using inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the levels of all the PTEs analysed in the abandoned mine soil samples were significantly (p < 0.05) higher than their corresponding values in the control soil from the non-mining area. Except for Cd, the mean concentrations of As, Cr, Cu, Mn, Ni, and Pb were significantly higher than the FAO/WHO maximum permissible limit. Except for Zn in guava fruits and Cd in avocado fruits, the mean concentration of PTEs in fruits from abandoned mines was significantly (p < 0.05) higher than their corresponding control values. In contrast, the mean levels of As, Cr, Cu, Mn, Ni, and Pb in the investigated fruits were significantly (p < 0.05) higher than FAO/WHO maximum permissible limits established for fruits. The studied fruits remarkably took up and bioaccumulated PTEs from the abandoned mine soil. Mango fruit significantly bioaccumulated As (5.40), Cd (3.40), and Zn (2.81). Guava fruit bioaccumulated As (1.50) and Cd (4.60), while avocado bioaccumulated As (3.53), Cd (3.80), and Zn (6.48). Banana bioaccumulated As (0.96), Cd (0.80), and Zn (6.78). The hazard quotient values for PTEs investigated in fruits for adults, and children were several folds greater than 1. The hazard index (HI) for the PTEs through consuming fruits for children and adults was greater than 1, indicating that possible health risks exist for both local children and adults. However, the HI values for the children were higher than those for adults, implying that children were exposed to more potential noncarcinogenic health risks from PTEs than adults. The total cancer risk (TCR) values for Cr and Ni for all the fruits studied were within 10-3-10-1, which is several-fold higher than the permissible limits (10-6 and < 10-4), indicating high carcinogenic risk. TCR values for Cd and Pb in all the fruits, except for Cd in guava and avocado fruits for children, were within the range of 10-5-10-4, indicating that they are associated with moderate risk. The CR values for all the PTEs in all the fruits for adults and children except for mango fruit adults were within 10-2-10-1, indicating high carcinogenic risk. In conclusion, the results and risk assessment provided by this study indicate that human exposure to fruits from abandoned mines suggests a high vulnerability of the local community to PTE toxicity. Long-term preventive measures to safeguard the health of the residents need to be put in place.

Indoor Air Quality Monitoring and Characterization of Airborne Workstations Pollutants within Detergent Production Plant.

The indoor air quality (IAQ) of five workstations within a detergent production unit was monitored. Particulate matter (PM) was measured using a gravitational settlement method, and later characterized. To ascertain the quality of indoor air within the workstations, which could directly or indirectly affect the health and performance of the workers, a physical inspection of the plant premises was undertaken. The mean value of the following air-quality parameters; particulate matter(PM2.5), particulate matter (PM10), formaldehyde (HCHO), volatile organic compounds (VOCs), carbon dioxide (CO2), temperature (T) and percent relative humidity (%RH) were obtained within the range of 24.5-48.5 µg/m3, 26.75-61.75 µg/m3, 0.0-0.012 mg/m3, 0.09-1.35 mg/m3, 1137-1265 ppm, 25.65-28.15 °C and 20.13-23.8%, respectively. Of the particulate matter components characterized, sodium oxide (Na2O)-25.30 mg/m3, aluminum oxide (Al2O3)-22.93 mg/m3, silicon dioxide (SiO2)-34.17 mg/m3, sulfur trioxide (SO3)-41.57 mg/m3, calcium oxide (CaO)-10.94 mg/m3 and iron III oxide (Fe2O3)-19.23 mg/m3, were of significance. These results, compared with international standards for industrial indoor air quality, suggest that indoor air contamination emanating from the chemicals used in production workstations is traced to the design of the plant structures and the activities carried out within the workstations.