Heavy metal content and potential health risk of geophagic white clay from the Kumasi Metropolis in Ghana

Abstract

Geophagia is the craving for non-food substances and commonly practiced among pregnant women and children. Consumption of geophagic clay samples can have serious implications on the health of the consumers as a result of the presence of toxic metals such as Pb, As, Hg and Cd. This study sought to determine the levels of heavy metals in the studied geophagic clay samples and to determine the potential risks of heavy metals as cumulative carcinogenic and non-carcinogenic risks to the health of the consumers via oral (ingestion) and dermal exposure routes. A total of thirty (30) white clay samples were analysed using Niton Thermo scientific XRF Analyser (Mobile Test S, NDTr-XL3t-86956, com 24). The clay samples were found to contain essential elements such as Ca, Fe, K and Zn as well as toxic metals such as As and Pb. There were isolated cases of the presence of Hg and all samples had Cd levels below detection. Health risk indices such as hazard quotient and cancer risk were calculated and the results indicated that consumers are likely to suffer from cancer through ingestion of geophagic clay. Bioaccessibility studies were done on zinc and it did not indicate any potential toxicity due to zincs essential nature. The levels of heavy metals in some of the geophagic clay consumed by some residents in the Kumasi were high compared to the Permitted Maximum Tolerable Daily Intake (PMTDI) by (WHO/FAO) and may pose potential health threat over time.

Potential health risk assessment of toxic metals contamination in clay eaten as pica (geophagia) among pregnant women of Ho in the Volta Region of Ghana.

“…Lead concentrations were observed to be below the mean exposure levels and was in contrast with findings of range of values 549-622.92 µg/Kg reported by Nkansah et al [27]. In line with our results, Tayie et al [10] reported 2.36 ± 0.08 mg/100g.…”

“…Tayie et al [10] reported 0.0 (nil) mg/Kg of Arsenic in clay samples in Accra were found to be lower than results obtained in this study. However, Nkansah et al [27] reported a range of 218-271 ppm from clay samples obtained from different parts of Kumasi Metropolis. Furthermore, Doe et al [32] also reported Arsenic levels of range 2.7-22.74 µg/g in nine (9) samples of clay samples collected from both Greater Accra and Kumasi of Ghana.…”

Assessment of Lead, Arsenic, Cadmium and Mercury Levels in Earthenware Clay Deposits at Mankessim, in Mfantsiman District, Ghana

“…These levels were within the safe levels of 80.0 µg/g 17 . One study observed a mean of 6.5 µg/g of Pb in geophagy soil in Tanzania 6 , while another study also reported 27.70±2.90 µg/g of Pb in geophagic white clay at Abuakwa in the Ashanti region of Ghana 18 . The lead levels in the samples from Mankessim were lower than the levels reported from other regions, where the clay is eaten directly.…”

Mineralogical Profile of Geophagic Clayey Soils Sold in Selected South African Informal Markets

“…Previous study revealed that exposure to Lead may cause intelligence decline in children and as well as cancer in adults [49]. Consumption of these clayey samples over a long time may result in serious health effects such as coma, seizure, the dysfunctioning of the kidney, liver and heart of the consumers [50]. Lead targets multiple organs in the human body due to its systemic toxicity which can lead to cardiovascular, renal, gastro-intestinal and haematological effects [50].…”

“…Consumption of these clayey samples over a long time may result in serious health effects such as coma, seizure, the dysfunctioning of the kidney, liver and heart of the consumers [50]. Lead targets multiple organs in the human body due to its systemic toxicity which can lead to cardiovascular, renal, gastro-intestinal and haematological effects [50]. Neurotoxicity, carcinogenicity and reproductive failures in adults are some of the effects of exposure to Lead (Pb) as contained in the data from the European Food Safety Authority (EFSA) [51].…”