Occurrence-Variability of Iodine in Salt-Water and Fresh-Water Seafoods

Abstract

Seafood make good delicacies for most families in Bayelsa State. Seafood accumulate iodine from the surrounding water, and are therefore a good dietary source of iodine. However, the economic importance of iodine in the body cannot be over-emphasized; adequate consumption of seaweed can eliminate iodine deficiency disorders, but excessive iodine intake is not good for health. Iodine variability needs to be taken into consideration since it explains why the same food item may have widely different iodine content depending on the locality where it was produced. In this paper, the iodine concentrations in Tilapia, Crayfish, Lobster, Shrimp, Prawn, and Crab of salt water and fresh water origins in Bayelsa State are reported. 25 g of sample (catfish, tilapia, crayfish, lobster, shrimp, prawn, and crab) was dried to constant weight. 0.2 g of dry weight sample was prepared via three stages; ashing, derivatization, and liquid-liquid extraction. The extractant was analyzed for iodine content using UV-VIS spectrophotometer at 320 nm. The iodine concentrations (mg/kg) in the salt water samples were found to be; catfish, 0.30; tilapia, 0.25; crayfish, 3.00; lobster, 2.70; shrimp, 2.64; prawn, 2.84; crab, 25.00. The iodine concentrations (mg/kg) in the salt water samples found to be; catfish, 0.021; tilapia, 0.023;crayfish, 0.200; lobster, 0.208; shrimp, 0.220; prawn, 0.258; crab, 1.786. These figures show that salt water seafoods contain iodine concentrations, 11 to 15 times the concentrations in the fresh water seafood. These differences were significant using a 2-tailed independent samples T test. Seafood of salt-water origin are very rich sources iodine.