Quality analyses of some common salts produced in Ghana

Abstract

This study presents and discusses the results of chemical analyses of the quality of selected salt samples produced in Ghana. With the exception of the Daboya salt producing areas in northern Ghana, the samples were collected from the seven major centres of salt production along the coast of Ghana from Axim to Keta. Five of the samples are from local salt producers whilst the remaining two samples are from the two salt factories namely, Panbros and Songhor salt factories. Two sets of samples were collected from each location during the rainny season and the dry season to account for seasonal variations. The Samples were then composited and taken as a representative sample from the location. The analyes were carried out the Ghana Atomic Energy Comission, Accra. The physicochemical parameters determined included pH, electrical conductivity and total dissolved solids. The metal and anions contents consisted of K, Na, Ca, Mg, Fe, Cu, Pb, As, Hg, Cd, SO4, I and Br. Generally the salts do not appear to meet the standard specifications of common salt by the Ghana Standard Board. They are generally low in Na, K, Ca and Mg. The Ca content ranging from 67.78 mgkg-1 to 228.94 mgkg-1 whilst Mg ranges from 24.03 to 41.61 mgkg-1 compared with the recommended value of 2000 mgkg-1 by The Ghana Standards Board(GSB). Fe, and Cu content of the salts is quite high but Pb, AS and Hg are low and refreshingly well below the recommended threshold values. Fe concentration varies from 5.88 to 18.56 mgkg- 1. Salt from the Songhor factory showed higher concentration values above the GSB levels as all the other salt samples showed values below the GSB value of 10 mgkg-1. The high Fe content may be attributable to contamination from ferruginous underlying bedrocks like Elmina sandstones and Togo and Buem sandstones, quartzites and shales. Apart from Keta salt, all the other salt samples had Cu concentrations above GSB permissible limit of 5 mgkg- The analysis of the trace metals revealed high levels of Cd,with all the samples showing Cd concentration excess of the recommended 0.5 mgkg-1 (maximum of GSB) 1. Approximately 40 % of the salt samples have SO4 concentrations exceeding the GSB maximum limit of 14000 mgkg-1 for edible salt. The study recommeds that salt ponds may be lined to reduce contamination and that salt produced by the traditional and artisanaal methods be purified before use.