Environmental and Health Risk Assessment of Cultivation Strategies in Tunja, Colombia
Author: Marianne Leuenberger, Diploma Thesis, 2005

Abstract
Agriculture is the most important source of income in the Colombian mountain regions. However, the agricultural production often is insufficient to earn a livelihood. Economy therefore can be considered as the major constraint and motivation for the choice of cultivation strategies. Consequently, Colombian farmers adopt different cultivation strategies in order to enhance their economic status by increasing the productivity. This thesis investigated the sustainability of the current cultivation strategies with the purpose of identifying room for improvement.
A set of analysis tools was established that permits a fast risk assessment of cultivation strategies. The tool box contains a dynamic pesticide exposure model, a nutrient balance and an erosion risk assessment tool. The pesticide exposure model was developed in Matlab Simulink and bases on the principle of Material Flux Analysis. Matlab Simulink allows for a fast and comfortable adaptation of case specific information, as parameters can easily be changed. Existing modeling tools were adapted for the nutrient balance and erosion risk assessment. The NUTMON model developed by the Food and Agricultural Organization FAO calculates the nutrient balance. Additionally, the Universal Soil Loss Equation estimates the erosion risk. In order to assess the risk of the case specific cultivation strategies, a survey on the use of pesticide and fertilizer was conducted with 48 households in the study area.
For the risk evaluation the output values were compared to standard risk assessment scales. Furthermore, the overall risk of a cultivation strategy was evaluated using the Multi Attributive Utility Theory MAUT. The risk assessment showed that standard pesticide use is not health endangering for farmers as well as for the general population. However, two strategies could be identified, that impose a potential health hazard for both occupational and general exposure. The fertilizer use was found to be inappropriate as for all strategies the phosphorus input outweighed the output. Additionally, the soil degradation risk is high for the majority of the areas in cultivation. The overall assessment indicates that sustainable farming is limited to low erosion risk areas under moderate use of fertilizers and pesticides.
As a conclusion, potential tradeoffs could be identified between increasing yields by using more agrochemicals and sustainability. Current strategies must be reconsidered in order to relieve pressure on natural and human resources.


Addresses:
Jaime Diaz, Msc
Department of Environmental Engineering, Universidad de Boyacá (UNIBOYACA)
Carrera 2 est Numero 64-169, Tunja, Colombia
Phone::++57 (098) 745 2597 or ++57 (098) 7450000 ext. 5402
jaimediaz[at]uniboyaca.edu.co

Regina Schöll, dipl. Umwelt-natw. ETH
Department of Environmental Sciences, Institute for Human-Environmental Systems (HES)
Universitätstrasse 22, ETH Zentrum , 8092 Zuerich, Switzerland
Phone: ++41 (044) 6325945
regina.schoell[at]env.ethz.ch

Marianne Leuenberger, dipl. Umwelt-natw. ETH
mleuenberger[at]gmail.com