Contaminants plant-protective agents

Over the last few decades, safety has become one of the most important topics related to food. From this view, quality control of vegetable raw materials has at first to cover the following issues natural and anthropogenic contaminants (e.g. heavy metals, pollution from industrial and private combustions, not professionally deposited waste products, radionuclides), residues of fertilisers (e.g. nitrate), plant-conditioning and plant-protective agents, filth, pests, the microbial status and the occurrence of microbial toxins. It is not possible to discuss all these aspects in detail however, with a focus on herbs and spices, two of them should be stressed more thoroughly. For further information, see [8]. 

The best method for protecting soils from heavy metal contamination is prevention. It is very expensive and difficult to clean contaminated sods. Some treatments include high temperature methods to produce a non-leachable material, solidifying agents to make cement-like material, and a washing process to remove contaminants. Several other techniques involve soil and crop management by adjusting the pH of the soil and the use of plants to remove metals from soil and water. 

---