Soil and Health Healthy soil is very important for human health because what is in the soil affects the health and quality of the food we eat that is derived from it. For example, soil is the main source of trace elements (e.g. iodine and cadmium), which are taken up by crops and plants, before being consumed by us. However, the human body only needs tiny amounts of these trace elements – too much or too little can make us ill. Factors such as soil acidity can affect the quantity of trace elements passing to crops, which subsequently affects us as well. A common example is a lack of iodine, which causes problems with the thyroid gland (vital for human growth and development). In contrast, too much cadmium can cause kidney failure. In the past, people working with soils (e.g. farmers and gardeners) were highly exposed to catching tetanus, a harmful bacteria living in the soil. These days, the risk has been substantially reduced in many countries through immunisations. Nevertheless, there are still many other threats such as the E.coli 0157 bacteria, which in extreme cases can result in death. Make sure you wash your hands after working with soil! Can you imagine eating soil? It is hard to believe, but in some parts of the world, particularly in less developed countries, people may have to resort to eating soil when there is nothing else available. However, research has shown that this can have serious health implications such as anaemia and retarded growth. Additionally, in particularly dry countries where soil is eroded by the wind, people can become seriously ill simply by inhaling soil particles. Research has shown that breathing in soil can cause elephantiasis (which is the swelling of limbs due to the blockage of the lymph nodes) and even cancer. Investigating the links between soil and our health has become an increasing priority for soil scientists. However, in order to achieve this, they still need to work more closely with geochemists, medical scientists and food and farming experts.