Seasonal dynamics of atmospheric heavy metals and total hydrocarbon content at the Edonwhii Beach, Nigeria
摘要
Edonwhii Beach, located within a major oil- and gas-influenced coastal corridor, is increasingly vulnerable to atmospheric contamination from heavy metals and total hydrocarbon content (THC). This study assessed seasonal and spatial variations of Pb, As, Cr, Cd, Ni, V, and THC, and evaluated the influence of meteorological parameters on pollutant behaviour. Air samples were collected from ten stations using Institute of Occupational Medicine (IOM) samplers. Heavy metals were quantified using atomic absorption spectroscopy, while THC and field meteorological parameters (temperature, relative humidity, wind speed, and pressure) were concurrently measured. Dry-season concentrations were markedly higher, with mean values (µg/m3) of Pb (1.935 ± 0.41), As (0.036 ± 0.02), Ni (1.083 ± 0.50), and THC (1.788 ± 0.48), compared to wet-season levels of Pb (0.207 ± 0.10), As (0.007 ± 0.004), Ni (0.211 ± 0.09), and THC (0.585 ± 0.20). Correlation analysis revealed strong positive relationships (r = 0.667–0.927, p < 0.01) among Pb, Cr, Cd, Ni, V, THC, temperature, and relative humidity, suggesting shared combustion-related and anthropogenic sources, whereas weaker correlations for As (r = 0.126–0.451) indicate partial geogenic contributions. Analysis of variance demonstrated pronounced seasonal variability, particularly for THC (F = 112.478) and Cr (F = 52.208). Health risk assessment showed hazard quotients (HQs) exceeding unity for all assessed pollutants in both seasons, with significantly elevated dry-season risks driven by Ni, As, Cd, and THC (HQ range: 4–9). Although wet-season rainfall reduced exposure levels substantially, risk thresholds remained above recommended safety limits. Meteorological conditions strongly governed pollutant dynamics: elevated temperatures, lower humidity, and minimal rainfall during the dry season enhanced atmospheric stability, dust resuspension, and hydrocarbon volatilization, while wet-season precipitation and stronger winds facilitated dispersion and removal. The findings underscore the need for meteorology-responsive emission control and targeted mitigation strategies in coastal fishing communities exposed to cumulative combustion-related pollution.