Risk Assessment of Pesticides Applied in Paddy Rice Fields in the European Union

摘要

In many parts of the world rice is an important if not the most important crop for the foodsupply of people. Although there are several crop management systems for growing rice often paddyfields are used in the production of rice. Sometimes huge fields are sown with rice; sometimes thescales of the fields are much smaller. Often the application of plant protection products is needed totake care of good quality of the rice crop as well as the yield. The registration decision in the European Union (EU) includes an evaluation of the efficacy ofthe products as well as side effects on humans, including worker exposure and public health effects,and on the environment, including non-target organisms, like fish and birds. For the environmentalrisk assessment a tiered system has been set up to evaluate the non-target risks of plant protectionproducts in the application to paddy rice fields taking into account the water management of thefields. To perform the risk assessment for rice paddies first it had to be decided whether or not thestandard data set would be sufficient. Depending on the characteristics of the substance the registrant may decide which data should be needed to carry out a risk assessment. The main differencewith data requirements for plant protection products in other crops was the additional possibility toperform a separate degradation study in paddy water. The tiered approach consists in step 1 of three situations again depending on the known characteristics like degradation and sorption. If the substance sorbs to soil particles very well or the degradation in soil or water/sediment systems is quick the risk assessment may come to an early decisionof no risk. If however,the criterion in step 1 is breached the higher tier 2 may be entered and additional calculations or fate and/or effect studies may be required. The paper describes the equations that rule the calculations for the step 1 approach where a distinction is made in la)no degradation and no sorption, Ib)degradation and no sorption and Ic)degradation and sorption. The methods developed have proven to be useful in the risk assessment for substances appliedin paddy rice fields by the registrant who is able to determine whether or not a safe use of the substance is possible and for registration authorities to grant registration to guarantee that substancesdo not have unacceptable side effects and therefore public health and the environment stay protected.