the importants of salt

Obtaining salt
1. Mining
  1. Large earth moving equipment is used to extract rock salt. This method of extraction leaves the salt with insoluble impurities such as reddish clay. This kind of salt is used to put on roads during freezing weather and does not need to be pure.
2. Solution in water
  1. when pure salt for industrial purposes is needed a different method is used. Water is forced down a borehole into rock. The salt dissolves making a solution of brine and this solution is withdrawn to the surface and pumped to a purification plant. Water is evaporated from the brine under a range of pressures making the process more efficient. The salt crystallises and is separated from any remaining brine by filtering or using a centrifuge.
Environmental impact
1. Extracting salt in solution can create large underground caverns. This can lead to bedrock collapsing and as a consequence, cause the lowering of the Earth’s surface. This is known as subsidence. It can be avoided by sensibly spacing out the holes created so the surface is supported by a sufficient amount of rock underground.
Risk of salt
1. Salt (sodium chloride) is used in foods as a flavouring and preservative. Humans need sodium in their diet to allow the body to carry out essential functions. The main sources of salt in our diet are processed meats and fish, cereal products and some dairy products.
2. Studies have shown that eating too much salt can increase a person’s blood pressure. Having high blood pressure increases the risk of heart disease and having a stroke.
3. Government departments such as the Department of Health and the Department for Environment, Food and Rural Affairs are involved in assessing what level of risk is acceptable in foods. They may respond to concerns that people are putting their health at risk by eating too much salt by carrying out risk assessments on foods and advising the population.
Perceived and measured risk
1. People’s perception of a particular risk can often differ from the statistically calculated risk. The risk of unfamiliar things (such as skydiving) and things that have an invisible effect (like ionising radiation) is often over-estimated by people. Attempts are frequently made to assess the chance of something happening and the consequences if it did.
2. Sometimes there is not enough evidence to say for certain how great the risk is for an action. For example, the information offered by many reports on the adverse effects of a high-sodium diet is challenged by others who suggest there is no scientific proof for this, and that in fact a low-sodium diet could be harmful.

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the importants of salt

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