**7. Conclusions**

The present study describes the framework for evaluating average monthly concentration of agricultural non point source pollution due to herbicide atrazine in streams by fuzzy rule based model with FCM utilizing limited amount of data. The values of statistical performance evaluation criteria indicate the model is able to simulate the behaviour of diffuse pollution sources from agricultural fields like attrazin in streams. The fuzzy rule based model with FCM performs comparatively better than the fuzzy rule based model without FCM and even with more fuzzy partitions. The proposed methodology also performs better than the ANN model when applied to the same problem. However, the model predicts with lesser accuracy for the intermediate months concentration measurement values including peak values. An extensive evaluation of the effect of more number of FCM based fuzzy centers and shapes of membership functions may fully establish the applicability of the methodology.

However, the proposed fuzzy rule based approach with FCM uses least amount of information in terms of number of inputs required, incorporate prior knowledge about fuzzy partitions, and also uses linguistic variables which make it relatively easy to interpret the rules. Prior knowledge about the physical system in the form of rule base can also be directly incorporated in the suggested approach. This preliminary study shows that the developed fuzzy rule based approach with FCM is potential suited to estimation of diffuse pollution concentration like atrazine in streams.

#### **8. References**


performance is also affected due to limited data sets. In the present study, the inputs were assigned with triangular shape. Further improvement in the performance of the methodology may be possible with more extensive evaluations of membership functions shape, number of data centers for membership functions for each variables, and overlap between two membership functions. Present methodology utilized centroid method for defuzzification. Performance of other defuzzification method also need to be investigated. The error in prediction of peak values shows the limitation of the methodology. However, these results show potential applicability of the proposed methodology. The main advantage of the developed methodology is incorporate some prior knowledge into the model frame work, and its ability to perform in case of limited availability of data than other

The present study describes the framework for evaluating average monthly concentration of agricultural non point source pollution due to herbicide atrazine in streams by fuzzy rule based model with FCM utilizing limited amount of data. The values of statistical performance evaluation criteria indicate the model is able to simulate the behaviour of diffuse pollution sources from agricultural fields like attrazin in streams. The fuzzy rule based model with FCM performs comparatively better than the fuzzy rule based model without FCM and even with more fuzzy partitions. The proposed methodology also performs better than the ANN model when applied to the same problem. However, the model predicts with lesser accuracy for the intermediate months concentration measurement values including peak values. An extensive evaluation of the effect of more number of FCM based fuzzy centers and shapes of membership functions may fully

However, the proposed fuzzy rule based approach with FCM uses least amount of information in terms of number of inputs required, incorporate prior knowledge about fuzzy partitions, and also uses linguistic variables which make it relatively easy to interpret the rules. Prior knowledge about the physical system in the form of rule base can also be directly incorporated in the suggested approach. This preliminary study shows that the developed fuzzy rule based approach with FCM is potential suited to estimation of diffuse

ASCE Task Committee on Definition of Criteria for Evaluation of Watershed Models (1993)

Arnold, J.G., Allen, P.M., Bernhardt, G. (1983) A comprehensive surfacegroundwater flow

Baker D.B., Richards R.P. (1990) Transport of soluble pesticides through drainage networks

Battaglin, W. A. and Goolsby, D. A., 1997. Statistical modeling of agricultural chemical

Bezdek J. C. (1981) Pattern Recognition with Fuzzy Objective Function Algoritms. Plenum

occurrence in Midwestern Rivers. *Journal of Hydrology*, 196, 1-25.

Criteria for evaluation of watershed models. *J. Irrig. Drain. Eng.* ASCE 119(3): 429–

in large agricultural river basins, In: Kurtz D.A. (Ed.), Long Range Transport of

methods such as ANN.

establish the applicability of the methodology.

pollution concentration like atrazine in streams.

model. *Journal of Hydrology* 142: 47–69.

Pesticides. Lewis Publishers, Inc., Chelsea, MI.

**7. Conclusions** 

**8. References** 

442.

Press, New York.


**14** 

*Hungary* 

**Forty Years with Glyphosate** 

*Department of Ecotoxicology and Environmental Analysis, Plant Protection Institute,* 

If one were to pick the most notified pesticide of the turn of the millennium, the choice would most likely be glyphosate. Although DDT remains to be the all-time star in the Hall of Fame of pesticides, the second most admitted pesticide active ingredient must be the

Indeed, the two boasted pesticides show certain similarities in their history of discovery and fate. Both were synthesised first several decades prior to the discovery of their pesticide action. DDT and glyphosate were first described as chemical compounds 65 and 21 years before their discovery as pesticides, respectively. Both fulfilled extensive market need, therefore, both burst into mass application right after the discovery of their insecticide/herbicide activity. They both were, to some extent, connected to wars: a great part of the use of DDT was (and remains to be) hygienic, particularly after Word War II, but also the Vietnam War; while glyphosate plays an eminent role in the "drug war" (Plan Colombia) as a defoliant of marijuana fields in Mexico and South America. And last, not least, ecologically unfavourable characteristics of both was applauded as advantageous: the persistence of DDT had been seen initially as a benefit of long lasting activity, and the zwitterionic structure and consequent outstanding water solubility of glyphosate, unusual among pesticides, also used to be praised, before the environmental or ecotoxicological

Yet there are marked differences as well between these two prominent pesticide active ingredients. Meanwhile the career of DDT lasted a little over three decades until becoming banned (mostly) worldwide, the history of glyphosate has gone beyond that by now, since the discovery of its herbicidal action (Baird et al., 1971). And while DDT is the only Nobel prize laureate pesticide, glyphosate was the "first billion dollar product" of the pesticide industry (Franz et al., 1997). Moreover, meanwhile the course of DDT was rather simple: rapid rise into mass utlilisation, discovery of environmental persistence, development of pest resistance, loss of efficacy, and subsequent ban; the history of glyphosate is far more diverse: its business success progressed uncumbered, receiving two major boosts. First, the patent protection of glyphosate preparations was renewed in the US in 1991 for another decade on the basis of application advantages due to formulation novelties, and second, its sales were further strengthened outside Europe with the spread of glyphosate-tolerant (GT) genetically modified (GM) crops. This market success has been limited significantly neither

phosphonomethylglycine type compound of Monsanto Company, glyphosate.

disadvantages of these characteristics were understood.

**1. Introduction** 

András Székács and Béla Darvas

*Hungarian Academy of Sciences* 

