Probabilistic Health Risk Assessment of Iodine Exposure in Khulna, Bangladesh

In this study, the concentrations of iodine in household salt samples (n=690) were determined by following the iodometric titration method, and the health risks of Bangladeshi people were assessed based on the semi-probabilistic approach and the United States Environmental Protection Agency (USEPA) deterministic model. After adjusting 20% of cooking losses, the iodine concentration (mean, range) in salt samples of Phultala, Dighalia, Terokhada, Rupsha, Batiaghata, Dumuria, Paikgacha, Koyra, Dacope, and KCC were (29.68±8.67, 14.39–48.26), (31.05±6.68, 15.24–43.18), (26.94±5.57, 16.09–45.72), (24.33±5.61, 12.70–37.26), (26.69±6.73, 10.16–44.87), (27.20±8.44, 9.31–53.34), (27.71±8.09, 8.46–47.42), (28.39±7.80, 11.01–46.57), (28.20±7.97, 3.38–49.10), and (29.21±6.62, 18.62–40.64) mg/kg, respectively. The iodine contents in 97.25% of samples were within the standard fortification level of Bangladesh (15–50 mg/kg), while 2.61% of samples were below this limit. The semi-probabilistic risk assessment studies showed that 80.14% of samples at a low ingestion rate could provide optimal nutrition (150–299 μg/day) to the whole population. Contrarily, at medium, moderate-high, and high consumption rates 34.93%, 65.22%, and 85.94% of samples, respectively belonged to above the requirements to excessive exposure categories (300–1100 μg/day), which might cause iodine-induced diseases. The target hazard quotient (THQ) values for the adults in most of the samples were within the threshold risk limit (THQ<1.0), whereas THQ values in 6.82–85.97% of samples for the children at low–high ingestion rates exceeded this limit, which revealed that the adults were almost safe but the children might face non-carcinogenic health effects. Therefore, regular monitoring of iodine concentration in iodized salts should be done to prevent iodine deficiency or iodine-induced disorders. 

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