Human Health Risk Assessment from Mercury-Contaminated Soil and Water in Abu Hamad Mining Market, Sudan

Abstract

Artisanal and small-scale gold mining (ASGM) poses a significant global threat due to mercury emissions and resulting health hazards. This study focuses on assessing these risks in the Abu Hamad ASGM community in Sudan. Utilizing the Mercury Analyzer 3000 (NIC), analyses of twelve soil samples (including one tailings sample) and seven water samples revealed the highest concentrations near amalgam burning locations: 34.8 mg/kg in soil (S06) and 3.26 µg/L in water (W03). Concentrations decrease with distance, with soil near burning exceeding tailings (S05 = 19.0 mg/kg). Hazard quotients indicate mercury vapor inhalation as the primary exposure route from soil, with the Hazard Index reaching 5.34 for adults and 33.4 for children close to amalgam burning sites. Water samples generally pose little risk except for W03, where children face potential danger via ingestion (HI = 1.74). These findings emphasize the urgent need for adopting retorts and eco-friendly practices to reduce mercury emissions and protect ASGM communities.

Assessment of Mercury Contamination in Water and Soil from Informal Artisanal Gold Mining: Implications for Environmental and Human Health in Darmali Area, Sudan

“…Interestingly, this concentration contains nearly 50% of the lower end of the range of mercury concentrations found in the tailings in the current study (5.01 mg/kg). Another study in the Abu Hamad Mining Market [29] exhibited higher mercury concentrations in tailings samples, measuring 19.0 mg/kg, which is relatively higher than the concentration found in this study. This difference may be attributed to the nature of the tailings in the present study, which primarily consist of reprocessed amalgamation tailings.…”

“…To contextualize the results within the ASGM context in Sudan, a study in the Abu Hamad ASGM center revealed that all individuals in the ASGM center are at risk, primarily from the ingestion and inhalation of mercury vapors [29], which is consistent with the findings of this study regarding the inhalation of mercury vapors. Water samples collected from ASGM processing centers posed significant human health risks, especially for children, even though they are not allowed to be present in those areas [29]. However, individuals in ASGM centers are directly or indirectly involved in ASGM activities.…”

“…However, one study conducted in the Abu Hamad Mining Market, where mercury is applied to the whole ore, unlike the amalgamation tailings being reprocessed by leaching as in the study area, found elevated concentrations in water samples collected within the ASGM area. The levels reached a maximum of 3.26 µg/L near the mercury amalgam sites, surpassing thresholds established by global organizations [29].…”

“…Interestingly, this concentration contains nearly 50% of the lower end of the range of mercury concentrations found in the tailings in the current study (5.01 mg/kg). Another study in the Abu Hamad Mining Market [29] exhibited The median concentrations of all sample groups exceeded the reference point concentration (0.016 mg/kg). In residential areas, individual sample surpassed this threshold, while 94.4% of farmland samples (17 out of 18 samples) also exceeded it.…”

“…The Minamata Convention on Mercury's Initial Assessment in Sudan identified the lack of data on mercury concentrations in tailings as a research gap [6]. Although some studies have analyzed mercury in ASGM tailings [29], the issue of reprocessed amalgamation tailings remains largely unexplored. This underscores the importance of continued research to fill these gaps and develop effective mitigation strategies.…”