Abstract

Small-scale salt mining in developing countries, including Tanzania, is among the major sources of consumed salt. This study aimed to assess the quality of salt from small-scale miners in Nkonkilanga, Singida region, Tanzania. Thirty salt samples were collected from small-scale miners and transported to Sokoine University of Agriculture, where they were analyzed for iodine content, moisture, particle size, color, purity, alkalinity, cadmium (Cd), lead (Pb), copper (Cu), and water insoluble matters. More than 63% of salt samples had lower iodine content (11.84 to 29.2 μg/g). However, all samples had higher moisture content (3.08 to 9.68%) than the maximum required limit (3%), larger particle sizes, and failed the color test. Moreover, 73.3% of salt samples failed a purity test. Regarding chemical hazards, Cd, Pb, and Cu levels were within the tolerable levels of <0.5, 2, and 2 μg/g, respectively. Although all salt samples passed the alkalinity test (<0.2%), they had higher water insoluble matters (0.44% to 1.89%) than the tolerable limit (<0.2%). In general, the salt was safe, but other physical parameters including iodine, moisture content, purity, color, and particle size did not comply with East African and Codex Alimentarius Commission standards. Training and monitoring of small-scale salt miners to improve salt quality are of paramount importance.

Key words: Salt, iodine content, heavy metals, salt quality, contaminants.