Table 1 Summary of qualitative study findings

Location for salt iodation

- Done in open space, on different heap sizes (range 2–3 tons) at production sites to reduce transport costs and labour.

- Iodation of salt was done at the sites; and iodated salt was loaded to trucks after iodation on sites.

- All sites have storage facilities for salt in good production seasons or in case of unpredicted rains.

Salt iodation equipment

- Knapsack spray pumps were commonly used in all sites because they are simple and affordable. They can last for six months to one year depending on usage.

- Conventional iodation machines e.g., cement mixers and machines with conveyors were found abandoned on sites due to high running costs and lack of spare parts.

Condition of knapsack spray pumps for salt iodation

- Some were rusty (metal components) and leaky (at the joints) resulting in wastage of iodated solution.

- Some spray pumps were blocked by crusting in the sprayer nozzle, impairing the speed of spraying and mixing. Loss of iodated solution was also dependent on the wind direction.

Procedure for salt iodation and mixing

- At least two people were working at each heap; one spraying potassium iodate (KIO₃) solution and one mixing salt with a shovel or spade.

- Three iodation steps were observed i) making the iodate solution, which less than 100 g was dissolved in more than 20 litres, resulting in less iodine concentrations in iodated salt (10 g KIO₃/litre of water is the correct concentration) ii) spraying and mixing not done adequately to acquire homogeneously mixed iodated salt, iii) packaging in 50 kg bags.

- In some instances iodate solution was sprayed only on the top layer of salt in the upright filled bag without further subsequent mixing.

Workers knowledge on salt iodation

- Workers had minimum skills in salt iodation techniques and knowledge of iodation rationale.

- Workers have shortage of weighing scales and were uncertain of the quantity of KIO₃ required to deliver the recommended iodine levels 40 – 80 ppm.

- Quantities of KIO₃ and volumes of water varied from one producer to another. Sometimes brine (with high density) was used for dissolving KIO₃, requiring more time to dissolve and possibly more pressure from the sprayer. Moisture content of iodated salt was measured by dry hand palm. The more the crystals of salt remains, the higher the moisture content in salt.

Supervision & monitoring

- Inadequate supervision (internal and external) to ensure quality control.

- Records of quantities of salt produced monthly/annually were available but did not indicate whether iodated or not.

- Field rapid test kits for iodated salt were adequately available in all sites but were not frequently used by workers to check the salt.

- All necessary requirements for titration were observed in two sites, and reported that trained quality control personnel have left the salt business leaving no replacement and therefore the equipments were found not in use and/or damaged.

- Salt workers were aware of salt testing by salt inspectors and the existence of salt regulations, therefore took effort to iodate top layers of the salt in bags to avoid troubles with enforcers.

Price of local iodation sprayers

Knapsack sprayer (20 litre capacity) costs Tanzanian Shillings 30,000 – 50,000 (equivalent US$ 25 – 40) and hand-bottle sprayers (one to two-litre capacity) cost Tanzania Shillings 6,000 – 10,000 (US$ 5.0 – 8.0).

Source of potassium iodate

Large salt producers import KIO₃ from India costing about US$ 22 per kilogram including freight and custom duties. Others buy from the Tanzania Salt Producers Association (TASPA) or from their fellow producers at a price of Tanzania Shillings 25,000 – 30,000 (US$ 20 – 25) per Kg.