Pesticides in the Modern World -Risks and Benefits 90 system of plants (Knutson et al., 1990).In contrast to the above, there are few cases of pesticides proved dangerous to public health.A typical example is the chlorinated hydrocarbon DDT, which was previously used against mosquitoes.The active substance DDT contributed greatly to reduce the spread of diseases like malaria, but was withdrawn in 1970 as it was considered dangerous for human and environment safety.Active substances are classified into five groups according to their toxicity.The first group (Ia) includes the extremely toxic agricultural plant protection agents, while the four other groups of substances are listed in order of decreasing toxicity (Ib, II, III).The fifth group (U) includes substances that are unlikely to become toxic to humans (International Programme on Chemical Safety, 2004).The adverse effects of these compounds may be observed in a short period (acute toxicity) or after a long time (chronic toxicity).In any case, it should be noted that, although the annual reported number of deaths by poisoning is 355.000,only a part of these poisonings, which is not specified in the World Health Report, are due to pesticides (WHO The World Health Report, 2003).Moreover, all cases of poisoning are due to accidents, like accidental ingestion or inhalation of chemicals, and not by food intake.However, the possibility of indication of various effects in consumer health through chronic toxicity cannot be ignored.Toxicity of a plant protection product depends on various factors, including chemical structure, temperature and humidity conditions, dose, duration of exposure, mode of action and the kind of exposure, like ingestion, inhalation, dermal etc. Different groups of pesticides and veterinary drugs are likely to be responsible for causing malaise, sore eyes, abnormalities to skin and respiratory system.Moreover, some pesticides and veterinary drugs are suspected of causing certain types of cancer, teratogenicity, chromosomal abnormalities and the weakening of the immune system of humans (Banerjee, 1999).The toxicity of various active substances, which can be detected in bee products, varies according to their chemical synthesis.In any case, poisoning or deaths due to the presence of toxic substances exclusively to bee products have not been reported.An exception is the death of infants, which was caused by Clostridium botulinum (Arnon, 1980).Even in these cases, however, the responsibility of honey has not been proven clearly, as this clostridium appears in the environment widely (Midura, 1996).In addition, 65% of infants that became ill had not eaten honey at all (Arnon et al., 1979).In any case, appropriate infant feeding prohibits the consumption of honey until the age of one year to eliminate possible poisoning from toxins of this micro-organism.Another way of classification of active substances, relates to the subject of this investigation, and is based on bee toxicity.In general, active substances are classified as very toxic, moderately toxic and non-toxic to bees.The most significant impact on bee colonies has been observed after treatments with plant protection products during the blooming.Most deaths occurred during the stage of forager worker bee that collects nectar and pollen.Moreover, larvae and domestic bees die because of pesticide residues detected in pollen.Although in many cases the concentration of pesticide found in pollen is not lethal, it is however likely to cause paralysis of bees, irritability, killing and replacing of the queen bee and generally abnormal behavior.This behavior can also be caused by substances that do not kill bees directly (e.g.carbaryl as active ingredient of Sevin®) but are transferred into the hive by foragers and affect the entire population (Sanford, 1993).The long-term persistence of many pesticides in stored pollen has also serious impact of bees' survival.Arsenic from paris green and calcium arsenate was present in pollen stored in comb analyzed six months after application.Methomyl residues persisted in honeybee combs for eight months.Methyl parathion from Penncap M, persisted in combs samples of stored pollen for 7 to 14 months after use and carbaryl similarly persisted over winter for 7-9 months (Erickson et al., 1983) www.intechopen.comPesticide Residues in Bee Products 91 Neonicotinoids like imidacloprid were also detected in stored pollen (Gregorc & Bozic, 2004;Chauzat et al., 2006).Also, the type of formulation and application of the pesticide in relation to toxicity caused to the bees proved particularly important.For example, the standardization of the active ingredient methyl parathion in microcapsules kills 13 times more bees than the formulation of the same substance as an emulsified solution.Furthermore, wettable powder or dust proved less dangerous than microcapsules, but also caused more deaths than aqueous or emulsified solutions (Sanford, 1993).Under the development of framework concerning consumer safety, the European Union created a warning system called RASFF (Rapid Alert System for Food and Feed), which reports hazardous foods and feeds, identified in the markets of the Member States.Bee products like honey and royal jelly have been reported occasionally.The main reason why they have been reported is the detection of residues of antibiotics that have been used by beekeepers to fight various diseases of bees.www.intechopen.com
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