Levels of Radon And Hydrochemistry of Hand-Dug Wells in the Keta Municipality

Abstract

Over exploitation of hand-dug wells in the Keta municipality is on the rise though less works on the radon levels and the hydrochemistry of hand-dug wells, have carried out in Keta. The objective of the research is to assess the quality of hand dug wells in the Keta Municipality with respect to Radon (222Rn) levels and hydrochemistry. The study was carried out in 10 communities in the Keta Municipality. Water samples were collected from 30 sampling points from November to March. Physical parameter (pH, salinity, alkalinity, TDS) were analysed in the field, whereas chemical parameters were analysed in the laboratory for radon and the hydrochemistry parameters. A t-test was conducted to find the differences in the seasons using mathematical analytical tool MATLAB R2015a (The Math Works Inc., Natick, Massachusetts US. MATLAB R2015a, 2015). Differences were considered significant at a p-value of 0.05. The results revealed significant differences in pH (7.14 –9.29), salinity (200 mg/L- 3830 mg/L), TDS (149mg/L-9870 mg/L), chloride (17.99 mg/L- 2823 mg/L), Calcium (38.40 mg/L- 180.8 mg/L), Sodium (30 mg/L- 497 mg/L) and sulphate (2.81 mg/L-37.35 mg/L). Phosphate, magnesium, salinity, Total hardness, chloride and sulphate were beyond the WHO recommended levels. The water quality index had most of the water to be poor and unfit for drinking. The Comprehensive Pollution Index results showed 80% of the samples to be moderately polluted. The Sodium Adsorption Ratio values obtained showed that the water have permeability issues with 93.33% being sodic waters having values above 13. Radon levels in the water ranged from 0.4 Bq/l - 111 Bq/l. The highest radon levels were recorded in Tetevikope. The annual effective dose for ingestion and inhalation ranged from 0μSv/y - 642.4μSv/y and 1.26μSv/y - 277μSv/y respectively. About 60% of the total samples were above the water quality limits set by World Health Organization (2011) and United State Environmental Protection Agency (2010). Based on the results obtained, it can be concluded that the water quality of the hand dug wells are unsafe for drinking and irrigation. However, the water from the hand dug wells present no significant health risk with respect to radon to the inhabitants. The results also show that the sea water intrusion into the groundwater aquifer has huge effects on the hydrochemistry of the hand-dug wells in the Keta Municipality.