Ecological and human risk assessments of heavy metal contamination of surface soils of auto-mechanic shops at Bogoso Junction, Tarkwa, Ghana.

There is a growing recognition that activities at automobile mechanic shops could contribute to heavy metal contamination of soils. This study seeks to evaluate the ecological and human risk assessments of heavy metal contamination of surface soils of auto-mechanic shops at Bogoso Junction, Tarkwa, Ghana. Herein, 20 composite soil samples were taken, acid-digested, and the concentrations of Cu, Pb, Cd, Mn, Ni, Cr, and Fe were measured using a flame atomic adsorption spectrometer (SHIMADZU, AA 7000). Appraising metal pollution indices, the potential human and ecological risks associated with analyzed metals were carried out. Findings of the present study indicate that the levels of analyzed metals of soils exceeded the control soil sample and the European Union standards for soil quality. The mean metal concentration increased in the order Fe > Mn > Cu > Ni > Pb > Cr > Cd in the soils. Outcomes of enrichment factor, geo-accumulation index, and contamination factor revealed that the soil quality is deteriorated with Cu, Pb, and Cd. The potential ecological risk identified Cd and Pb as the richest elements and offered a high ecological risk in all sampling sites. Furthermore, hazard quotient of analyzed metals depicted that Ni and Mn in urban soils of Bogoso Junction automobile mechanic shops may pose a threat to children (HI > 1). Dermal contact and inhalation of soil particles are the main exposure routes for children susceptibility. Specifically, cancer risk associated with Cd inhalation was 10 times greater than oral ingestion of Pb, showing a relatively high carcinogenic hazard to humans. Altogether, artisanal activities such as engine repair, welding and soldering, vehicle overhauling, and oil exchange at the automobile mechanic shops could deteriorate the soil quality resulting in ecological and human health implications within the vicinity of automobile mechanic shops in Ghana.

Oxidative Stress and Apoptosis in Bisphenol AF-Induced Neurotoxicity in Zebrafish Embryos.

Bisphenol AF (BPAF) is a structural counterpart of bisphenol A that is utilized in the food and beverage industry. The present study investigated the potential mechanisms in BPAF-induced neurotoxicity in zebrafish embryos. The BPAF concentrations (0.03, 0.1, 0.3, and 1.0 µM) had no obvious effect on hatching, mortality, and body length of zebrafish larvae, while curved tail and pericardial edema were observed in the 1.0 µM group at 72 and 96 h postfertilization (hpf). Locomotor activity of the larvae (at 120 hpf) significantly decreased from dark to light but increased from light to dark transitions in BPAF groups (0.1, 0.3, and 1.0 µM). Acridine orange showed that BPAF significantly increased green fluorescence protein intensity (22.6%) in the 1.0 µM group. Consistently, the induced apoptosis significantly up-regulated caspase 3 at 0.3 µM (1.95-fold) and 1.0 µM (2.26-fold) and bax at 0.3 µM (1.60-fold) and 1.0 µM (1.78-fold), whereas bcl-2 expression was significantly decreased at 0.3 µM (0.72-fold) and 1.0 µM (0.53-fold). In addition, increased reactive oxygen species concentrations at 0.3 µM (27%) and 1.0 µM (61.4%) resulted in suppressed superoxide dismutase and catalase activities. Moreover, quantitative polymerase chain reaction results showed that BPAF (0.3 and 1.0 µM) significantly altered normal dopaminergic signaling where dat was up-regulated, while drd2a and th1 were down-regulated, in a concentration-dependent manner. Aberrations in dopamine-related genes were congruous with the dysregulations in neurodevelopment genes (sox11b, pax6a, syn2a, and rob2). Our findings suggest that BPAF-evoked oxidative stress and apoptosis could translate into phenotypical behavioral and neurodevelopmental abnormalities. These highlights could provide theoretical reference for risk assessment and act as an early indicator to BPAF exposure. Environ Toxicol Chem 2022;41:2273-2284. © 2022 SETAC.