Food Safety and Health
There is a strong link between soils, health and food safety. The soil contains numerous minerals, usually in balanced amounts, providing essential nutrients for plants and animals and eventually for humans. There are two situations in which this supply to plants, animals and humans lacks reasonable balance. Firstly, soils can contain deficiencies in (too little) or surpluses of (too much) nutrients, which then become reflected in the supply to, and health of, plants, animals and humans. This is usually the result of inheritance from the parent rocks, which have released too much or too little of a particular element into the soil, so imbalancing nutrient supply. These situations can be a problem for soil health and for those that live and depend on the soil. Many of the soils that are subject to these problems worldwide are now reasonably well recognised, particularly in developed countries.
A more significant problem is the growing number of situations where human misuse of the soil has led to pollution or contamination. Most of these problems relate to increased industrialisation, particularly from the 18th, 19th and 20th centuries in the developed world, when much damage was done to soils, leaving a legacy of pollutants and contaminants. It is apparent today that rapid industrialisation in many of the developing countries is now also having a similar effect, with much pollution going unchecked, leading to severe land degradation. Such damage to soils leads in turn to soil, water and air pollution and these can interact to cause a variety of problems such as release of toxins and carcinogens, amongst others. Misuse of soil in this way threatens the ability of soils to meet reasonable safety standards and has jeopardised food production.
Soils have often been considered as a sink for pollutants but it is now recognised that in some situations soils can also act as a source of pollutants. We need to understand this 'sink-source' relationship to regulate the impact of pollutants and contaminants on the various uses of soil. This is vital if we are to rely on soils increasingly and more intensively in the future. Food safety is becoming a major issue in many countries. Soil has an extremely important part to play in securing this food safety because it has so many different functions, including adsorption of nutrients, filtering, leaching, flow control, storage and amelioration. Many of these functions are vital in planning food security. Knowledge of the properties of soils, the processes operating in them, and their distribution in the landscape, is essential for the management of contaminants and would-be soil pollutants in the soil system with respect to food safety.