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Open Access Highly Accessed Research article

Geophagy practices and the content of chemical elements in the soil eaten by pregnant women in artisanal and small scale gold mining communities in Tanzania

Elias C Nyanza1*, Mary Joseph2, Shahirose S Premji34, Deborah SK Thomas5 and Cynthia Mannion3

Author Affiliations

1 School of Public Health, Catholic University of Health and Allied Sciences, P.O. Box 1464, Bugando Area, Mwanza, Tanzania

2 Goodneighbours Tanzania, P.O. Box 33104, Dar es salaam, Boko Area, Kinondoni, Tanzania

3 Faculty of Nursing, University of Calgary, University of Calgary, 2500 University Drive, NW, Calgary, AB T2N 1 N4, Canada

4 Department of Community Health Sciences, Faculty of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB T2N 4Z6, Canada

5 Department of Geography & Environmental Sciences, University of Colorado Denver, PO Box 173364, Denver, CO 80217-3364, USA

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BMC Pregnancy and Childbirth 2014, 14:144  doi:10.1186/1471-2393-14-144

Published: 15 April 2014

Abstract

Background

Geophagy, a form of pica, is the deliberate consumption of soil and is relatively common across Sub-Saharan Africa. In Tanzania, pregnant women commonly eat soil sticks sold in the market (pemba), soil from walls of houses, termite mounds, and ground soil (kichuguu). The present study examined geophagy practices of pregnant women in a gold mining area of Geita District in northwestern Tanzania, and also examined the potential for exposure to chemical elements by testing soil samples.

Method

We conducted a cross sectional study using a convenience sample of 340 pregnant women, ranging in age from 15–49 years, who attended six government antenatal clinics in the Geita District, Tanzania. Structured interviews were conducted in June-August, 2012, to understand geophagy practices. In addition, soil samples taken from sources identified by pregnant women practicing geophagy were analysed for mineral element content.

Results

Geophagy was reported by 155 (45.6%) pregnant women with 85 (54.8%) initiating the practice in the first trimester. A total of 101 (65%) pregnant women reported eating soil 2 to 3 times per day while 20 (13%) ate soil more than 3 times per day. Of 155 pregnant women 107 (69%) bought pemba from local shops, while 48 (31%) consumed ground soil kichuguu. The estimated mean quantity of soil consumed from pemba was 62.5 grams/day. Arsenic, chromium, copper, iron, manganese, nickel and zinc levels were found in both pemba and kichuguu samples. Cadmium and mercury were found only in the kichuguu samples. Based on daily intake estimates, arsenic, copper and manganese for kichuguu and copper and manganese for pemba samples exceed the oral Minimum Risk Levels designated by the U.S. Agency for Toxic Substance and Disease Registry.

Conclusion

Almost 50% of participants practiced geophagy in Geita District consistent with other reports from Africa. Both pemba and kichuguu contained chemical elements at varying concentration, mostly above MRLs. As such, pregnant women who eat soil in Geita District are exposed to potentially high levels of chemical elements, depending upon frequency of consumption, daily amount consumed and the source location of soil eaten.

Keywords:
Geophagy; Pica; Pregnancy; Chemical elements; Soil pollution; Arsenic; Mercury