Plant protection products toxicity

In general, plant-protection products are biocidal active substances and are therefore by nature toxic to target organisms. At least some of them are also toxic to humans therefore, the safe use of plant-protection products presupposes, among other things, an evaluation of worker exposure during re-entry, an adequate risk assessment on the basis of the various practical scenarios in agriculture and horticulture, and, if necessary, specific instructions for worker protection on the product label. 

This step contains an initial evaluation of possible risk to workers due to the toxicity of the plant-protection product. The evaluation is based on the classification and labeling requirements established within the European Community. In order to address the specific need to safeguard the health of workers during re-entry to treated crops, the general safety advice (S-phrases) has to be specified in detail. Delineation of specific instructions for workers regarding classification and labeling is provided below. If no classification or... 

Within the EU, experimental human toxicity smdies must not be conducted specifically for the purpose of hazard assessment of biocides according to the EU Biocidal Product Directive (EC 1998), or pesticides according to the EU Plant Protection Product Directive (EC 1991). 

The basic idea of the CLH process is the transfer of responsibility for classification and labeling from industrial companies to authorities on a European Community level. In case of active substances in biocidal or plant protection products, all intrinsic properties including physicochemical properties, human health hazards, and environmental hazards are subject to the harmonization. By contrast, in the case of chemicals which are used in other application fields only some specific hazard classes are considered in the CLH procedure. According to Article 36 of the CLP Regulation, these are respiratory sensitization, carcinogenicity, germ cell mutagenicity, and reproductive toxicity. Consequently, these provisions have... 

Tests with three soil invertebrate groups, lumbricid earthworms, enchytraeids and springtails, have been ratified. All three tests were developed originally for testing the toxicity of plant protection products in an artificial soil consisting of 10% peat,... 

Birds and mammals may be exposed to toxic effects of active substances following the field use of plant protection products. In current ecotoxicological risk assessments for pesticide registration endpoints, of toxicity tests are compared with estimations of the expected exposure of wildlife species in the field. From the data on toxicity and exposure, a risk quotient (e.g., TER Toxicity Exposure Ratio) is calculated and compared to safety factors (e.g., 10 for acute risk). If the quotient is larger than the safety factor, the risk is considered to be acceptable. On the other hand, if the quotient is below the safety factor, a possible risk is indicated and further refinement of the input parameters is necessary to show that no risk for wildlife species will exist when the substance is applied under practical field conditions. 

In France, in 1943, a law on the registration of plant protection products used in agriculture was adopted. The tests required at this time for plant protection products to become commercialized were limited. They mainly dealt with the biological efficacy of the product and acute toxicity tests on rats. No test was requested on the side-effects of the products on nontar-geted insects, such as pollinator insects. Nevertheless, even at this time. 

Data are also required on the toxicity of the plant protection product. Further details on when these data are required can be found in the Aquatic Guidance Document, as well as Section 10.2.1 of Directive 96/12/EC. 

Further problems to be taken into consideration in plant production are contaminations with heavy metals, damages caused by pests and diseases, and residues of plant protection products. The most important toxic heavy metals Cd, Hg, Pb, and Zn, but also Cu, Ni, and Mn may in uence the plant growth severely and by that way also the essential oil, as they may act as cofactors in the plant enzyme system. But as contaminants, they remain in the plant residue after distillation (Zheljazkov and Nielsen, 1996 Zheljazkov et al., 1997). Some plant species, for example, yarrow and chamomile accumulate heavy metals to a greater extent. This is, however, problematic for using the crude drug or for deposition of distillation wastes mainly. The same is valid for the microbial contamination of the plant material. More important in the production of essential oils are pests and diseases that cause damages to the plant material and sometimes alterations in the biosynthesis but little is known in this respect. 

Stockholm Convention This bans the production and use of certain Persistent Organic Pollutants (POPs) or severely restricts release. It applies to plant protection agents, industral chemicals and highly toxic by-products and incineration processes, such as dioxins and furans. 

Protective equipment must be used for protection from toxic gases and vapors and are required for normal hazardous operations such as working in a spray-painting plant, production and use of toxic chemicals, and fumigant use. Safe respiratory protective equipment is required for all these activities. 

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