Herbs heavy metals

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]. 

There are many review articles concerning application of USE in food technology [57] and for isolation of bioactive substances from herbs and other plant materials [58], as well as leaching of heavy metals from environmental and industrial samples [59]. Application of ultrasound during sequential extraction of trace elements significantly shortens the whole procedure however, for satisfactory efficiency it is necessary to increase the temperature and modify the matrix. 

The authors of a survey of German importers of Chinese herbs concluded that only rarely had herbal drugs to be returned because of contamination (117). The authors also stated that a 100% check for all possible contaminants is not possible. However, there have been many reports of adulteration and contamination relate to Chinese herbal remedies (118). Instances include adulteration/contamination with conventional drugs (119,120), heavy metals (121-127), and other substances (128,129). 

Consumers and practitioners should be aware that herbal products can cause adverse reactions or result in negative outcomes for a number of reasons. First, consumers or herbalists may not recognize the seriousness of a medical condition, which might require more aggressive medical treatment than herbs can provide. Second, problems can arise from aUei ic reactions, misidentification of herbal products, intentional or unintentional contamination of herbal products with heavy metals or other harmful substances, or mistakes in the dosage. Third, herbs and conventional medications may interact and exacerbate an existing... 

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