The hydrochemistry of water resources in selected mining communities in Tarkwa John Manyimadin Kusimi a, ⁎, Bertha Ansaah Kusimi b, 1 a Dept. of Geography & Resource Development, University of Ghana, Legon, Accra, Ghana b Environmental Science Programme, University of Ghana, Legon, Accra, Ghana abstract article info Article history: Received 10 September 2010 Accepted 13 September 2011 Available online 19 September 2011 Keywords: Heavy metals Hydrochemistry Mining Tarkwa Trace metals Water quality analysis Tarkwa is one of the most heavily mined localities in Ghana. Mining activities are associated with the release of toxic chemicals into the environment which pollute water resources in mining communities within the catchment of mines. The study was undertaken in communities within the catchment of three mining com- panies in Tarkwa to find out the impact of mining on the water quality of these settlements. The research was conducted by taken water samples of both surface and groundwater within these communities for laboratory analysis using Instrumental Neutron Activation Analysis (INAA) and Atomic Absorption Spectrophotometer (AAS) to determine the concentration levels of elements in the water. The analysis showed that, concentration levels of certain elements namely, iron, cadmium, copper, cyanide, arsenic and zinc were beyond allowable limits of World Health Organization (WHO), Ghana Standards Board (GSB) and Ghana Water Company (GWC) guidelines for drinking water in certain samples confirming the communities' perception that, their water resources are polluted owing to the mining activities. Excess levels of iron and arsenic were found in 65% of samples, cadmium 23%, copper 58%, cyanide 12%, and zinc 42%. Concentration levels of 3.75 mg/l and 1.76 mg/l of iron and arsenic were detected in certain samples. Maximum concentration level for cadmium was 0.37 mg/l, copper 7.45 mg/l, cyanide 8 mg/l and zinc 10.2 mg/l. Toxicity level of other elements such as mercury, lead, chloride, nitrates and others was low. Except mercury and cyanide whose presence in the environment is introduced by mining activities, the presence of other elements in water resources is mobilized from weathered rocks of the underlying geology. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Ghana is heavily mineralized due to the abundance of geological formations of proterozoic rocks of the Birimian and Tarkwaian in the country especially within the south western part (Kesse, 1985). These rocks are rich in gold deposits which have been mined since the colonial times till today. The Tarkwa-Nseum Municipality in the Western Region, which was formerly part of the Wassa West District now split into Tarkwa-Nsuem Municipality and the Prestea-Huni Valley District has been one of the mining enclaves in this country. Out of 16 multinational companies in Ghana, eight are located in this mining enclave, and three in Tarkwa township. The three com- panies which are the focus of the study are Gold Fields Ghana Ltd (GGL), Anglogold Ashanti (AGA) – Iduapriem Mine and Ghana Man- ganese Company (GMC) – Nsuta. Despite being a major export earner for the nation, gold productivity declined from the 1960s till the mid 1980s when the Government adopted Economic Recovery Programme (ERP) to revamp the economy. New minerals and mining laws such as Minerals and Mining Law (PNDCL 153) were enacted in 1986 in an effort to reverse the decline in the mining industry. The law put in place a number of concessions for mining investors and also provisions were made for generous capital allowances and reduced income taxes (http://www.oxfamamerica. org). As a result of the attractive investment climate, mineral produc- tion and contribution to gross foreign earnings of the economy have been quite significant. The ramifications of this historical record of min- ing have not only been that of economic prosperity but also of environ- mental pollution, land appropriation, displacement of people from their lands, environmental devastation and marginalization and oppression of people belonging to the lower economic sectors of the society partic- ularly women. The industry has been associated with serious environmental and health impacts. Mining communities have been victims of air and water pollution as well as other forms of environmental degradation resulting from mining operations. In Tarkwa the principal environ- mental problems caused by the mining industry both large and small scale include the release of heavy metals and hazardous chemi- cals into the environment, deforestation which leads to land degrada- tion, and physical hazards which threaten the health and safety of people at mine sites and communities. The release of heavy metals and hazardous chemicals into the environment is generated mainly Journal of Geochemical Exploration 112 (2012) 252–261 ⁎ Corresponding author. Tel.: + 233 302500394. E-mail addresses: jmkusimi@ug.edu.gh (J.M. Kusimi), berthaashitey@yahoo.com (B.A. Kusimi). 1 Tel.: + 233 302500305. 0375-6742/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.gexplo.2011.09.003 Contents lists available at SciVerse ScienceDirect Journal of Geochemical Exploration journal homepage: www.elsevier.com/locate/jgeoexp