Exposure to toxicants in soil and bottom ash deposits in Agbogbloshie, Ghana: human health risk assessment.

Recycling of e-waste using informal or crude techniques poses serious health risk not only to the workers but also to the environment as whole. It is against this background that this paper sought to measure health risk faced by informal e-waste workers from exposure to toxicants such as lead, cadmium, chromium, copper, arsenic, tin, zinc and cobalt via oral and dermal contact with bottom ash and soil. Using random sampling techniques, 3 separate sites each (where burning and manual dismantling of e-wastes are usually carried) were identified, and a total of 402 samples were collected. The samples were analysed using standard methods for chemical analysis prescribed by the American Water Works Association (AWWA). Concentrations of Pb, Cd, Cr, Cu, As, Sn, Zn and Co in bottom ash samples from location ASH1 are 5388 ± 0.02 mg/kg (Pb), 2.39 ± 0.01 mg/kg (Cd), 42 ± 0.05 mg/kg (Cr), 7940 ± 0.01 mg/kg (Cu), 20 ± 0.07 mg/kg (As), 225 ± 0.04 mg/kg (Sn), 276 ± 0.04 mg/kg (Zn) and 123 ± 0.04 mg/kg (Co), while concentrations of the aforementioned toxicants in soil samples at location ASG1 are as follows: 1685 ± 0.14 mg/kg (Pb), 26.89 ± 0.30 mg/kg (Cd), 36.86 ± 0.02 mg/kg (Cr), 1427 ± 0.08 mg/kg (Cu), 1622 ± 0.12 mg/kg (As), 234 ± 0.25 mg/kg (Sn), 783 ± 0.31 mg/kg (Zn) and 135 ± 0.01 mg/kg (Co); used as input parameters in assessing health risk faced by workers. The results of cancer health risk faced by e-waste workers due to accidental ingestion of As in bottom ash at ASH1 is 4.3 × 10-3 (CTE) and 6.5 × 10-2 (RME), i.e. approximately 4 out of 1000 e-waste workers are likely to suffer from cancer-related diseases via central tendency exposure (CTE parameters), and 7 out of every 100 e-waste worker is also likely to suffer from cancer cases by reasonable maximum exposure (RME) parameters, respectively. The cancer health risk results for the other sampling sites were found to have exceeded the acceptable USEPA cancer risk value of 1 × 10-4 to 1 × 10-6 (i.e. 1 case of cancer per every 10,000 people to 1 case of cancer per every 1,000,000 people). The non-cancer health risk results for all the toxicants were higher in all the locations for both adult and children working the e-waste site. From the findings of this study, the government of Ghana has to immediately put in place policies that would address the safety of the e-waste workers as well as protect the environment.

Evaluation of lead and mercury neurotoxic health risk by resident children in the Obuasi municipality, Ghana.

This study assesses neurotoxic effects associated with exposure to lead and mercury in borehole, tap and surface water by resident children in the Obuasi municipality in accordance with USEPA risk assessment guidelines. From the results of the study, the hazard quotient for oral ingestion of mercury in tap water in Obuasi is 7.4 and 15 respectively via both central tendency exposure (CTE) and reasonable maximum exposure (RME) parameters, respectively. This means that approximately 7 and 15 (by both CTE and RME parameters, respectively) resident children in Obuasi are likely to show neurologic effects associated with exposure to mercury and lead such as increased nervousness, loss of memory and/or decrease in concentration, impaired writing ability and tremor.

Arsenic, cadmium, and mercury in cocoyam (Xanthosoma sagititolium) and watercocoyam (Colocasia esculenta) in Tarkwa a mining community.

Cocoyam (Xanthosoma sagititolium) and Watercocoyam (Colocasia esculenta) have gained increased importance in the diets of majority of people in developing countries such as Ghana. The concentration levels of arsenic, cadmium, and mercury in Cocoyam (X. sagititolium) and Watercocoyam (C. esculenta) in Tarkwa and its surrounding villages a mining community in Ghana were measured in this study. From the results of the study, the levels of arsenic, cadmium and mercury in X. sagititolium and C. esculenta were higher than the WHO recommended levels. These root tubers absorb or uptake toxic chemicals from the soil as a result of the mining operations. This means that, the consumption of X. sagititolium and C. esculenta by humans from such environments may pose a serious health risk. There is therefore the need for a concerted effort by all to minimize the negative impact of gold mining in the study area.

Cancer and non-cancer health risk from eating cassava grown in some mining communities in Ghana.

Food crops such as cassava, cocoyam and other tuber crops grown in mining communities uptake toxic or hazardous chemicals such as arsenic, and cadmium, from the soil. Cassava is a stable food for Ghanaians. This study evaluated human health risk from eating cassava grown in some mining communities in Ghana such as Bogoso, Prestea, Tarkwa and Tamso, which are important mining towns in the Western Region of Ghana. The study evaluated cancer and non-cancer health effects from eating cassava grown in the study areas in accordance with US Environmental Protection Agency's Risk Assessment guidelines. The results of the study revealed the following: cancer health risk for Tamso, 0.098 (RME--Reasonable Maximum Exposure) and 0.082 (CTE--Central Tendency Exposure). This means that approximately 10 and 8 out of 100 resident adults are likely to suffer from cancer related cases by RME and CTE parameters respectively. For Prestea, we have 0.010 and 0.12, which also means that approximately 1 out of 100 and 10 resident adults out of 100 are also likely to suffer from cancer related diseases by RME and CTE parameters. The results of the study obtained were found to be above the acceptable cancer risk range of 1x 10(-6) to 1x 10(-4), i.e., 1 case of cancer out of 1 million or 100,000 people respectively.

Non-cancer health risk assessment from exposure to cyanide by resident adults from the mining operations of Bogoso Gold Limited in Ghana.

Cyanide is a very toxic chemical that is used to extract gold from its ores. Wastewaters from gold mining companies such as Bogoso Gold Limited (BGL) contain cyanide and other potentially toxic chemicals that have adverse effects on human beings and aquatic organisms. This study was conducted to evaluate the human health risk assessment from exposure to free cyanide via oral and dermal contact of surface/underground water by resident adults within the concession of Bogoso Gold Limited. The chronic non-cancer health risk from exposure to cyanide in River Bogo Upstream is 230 and 43 (by Central Tendency Exposure (CTE) parameters respectively). This means that approximately 230 and 43 resident adults are likely to suffer diseases related to cyanide intoxication via oral and dermal contact respectively. For chronic exposure to River Bogo Downstream by resident adults, the non-cancer health risks are: 0.031 and 0.57 via oral and dermal contact for CTE parameters respectively, which also means that, the non-cancer health risks associated with cyanide intoxication is negligible as the hazard index is less than 1.0 via oral and dermal contacts respectively. The results showed that health risk for acute exposure to cyanide by the resident adults is very high. Hence the residents attribute most of the unexplained deaths in the communities to accidental ingestion and dermal contact of cyanide water.

Analysis of polycyclic aromatic hydrocarbons in street soil dust in Kumasi Metropolis of Ghana.

Concentrations of polycyclic aromatic hydrocarbons (PAHs) in street soil dust from streets in Kumasi Metropolis in the Ashanti Region of the Republic of Ghana have been measured in this study. The concentrations of the various types of PAHs identified in this study are as follows: Naphthalene (m/e 128) - 41,700 microg/kg, Acenaphthylene (m/e 152) - 99,300 microg/kg, Acenaphthene (m/e 154) - 111,200 microg/kg, Fluorene (m/e 166) - 8,900 microg/kg, Carbazole (m/e 167) - 3,500 microg/kg, phenathrene (m/e 178) - 12,900 microg/kg, Anthracene (m/e 178) - 5,400 microg/kg, Fluoranthene (m/e 202) - 16,200 microg/kg, Pyrene (m/e 202) - 15,000 microg/kg, Benzo[a]anthracene (m/e 228) - 13,800 microg/kg, Chrysene (m/e 228) - 33,600 microg/kg, Benzo[k]fluoranthene (m/e 252) - 45,700 microg/kg, Benzo[a]pyrene (m/e 252) - 27,900 microg/kg, Perylene (m/e 252) - 57,200 microg/kg and Benzo[g, h, i]perylene (m/e 276) - 47,000 microg/kg. The results of the study shows that road users, like resident living in buildings within these areas, those engaged in commercial activities like hawking, and the general public are at risk of exposure to the toxic effects of the various types of PAHs from the exhaust of vehicles into the environment. According to these results, there is the potential for exposure to high levels of PAHs for road users and those living in urban environments or along highways.