Estimating pesticide environmental risk scores with land use data and fugacity equilibrium models in Misiones, Argentina

In the Province of Misiones (NE Argentina), traditional agriculture was based on industrial crops like mate tea, tea and tobacco, which still occupy 93% of the cultivated land. Recently, a fast crop re-conversion process with citrus plantations intended for direct consumption began. This re-conversion implies a number of changes in the agricultural systems. In particular, an intensification in the use of agrochemical pesticides to control bacterial, fungic and parasitic (mites, flies, scales, etc.) citrus pests is to be expected, unless effective Integrated Pest Control Programs (IPCPs) are simultaneously and successfully implemented. In order to maintain environmental risks at current levels, an adequate timing of crop replacement, pesticide use and progress of IPCPs is required. Methods and results of the analysis of prospective increases in pesticide environmental risk derived from agricultural re-conversion in scenarios with and without IPCPs at various scales of land use units are presented. The results indicate that some spatial scales of citrus cropping imply an estimated 530-790% increase of the exposure of local residents to pesticides as compared to present levels, and 66-110% increases in average regional human exposures. A successful IPCP that would ameliorate the effect of crop re-conversion maintaining present risk scores should accomplish a reduction of 75% of the risk posed by pesticides used in citrus crops within the next 20 years. This would compensate for an estimate 9% annual crop re-conversion rate. The techniques and concepts used here to arrive to these estimates could be extended to the analysis of environmental risks posed by agricultural re-conversion processes in other regions where similar processes occur. (C) 2003 Elsevier B.V. All rights reserved.