Crop Protection Chemistry in Latin America
by Kenneth Racke
More than 225 scientists, government regulators, and industry leaders representing some 20 countries gathered in balmy Rio de Janeiro, Brazil during 9–12 November 2009 to participate in the 3rd IUPAC International Workshop on Crop Protection Chemistry in Latin America. The theme of the workshop was “Environment, Safety, and Regulation.” A key objective was to encourage exchange of the latest information regarding harmonized approaches for scientific and regulatory evaluation of pesticides in Brazil and the surrounding region.
The workshop was organized by the National Association of Specialists in Residues, Contaminants, and Organic Pollutants, the Brazilian Chemistry Association, and the IUPAC Division of Chemistry and the Environment (DCE or Division VI). Leadership for the workshop was provided by Irene Baptista de Alleluia of GARP. IUPAC contributions were coordinated by Laura McConnell and Ken Racke. Key local organizing team leaders were Celso Augusto Caldas Fernandes of ABQ and Pedro Luiz de Freitas of EMBRAPA.
Participants in the three-day workshop had the opportunity to attend 38 plenary and invited lectures and view more than 50 posters organized around five major scientific topics. Along with many excellent scientific presentations from international and regional experts, the program included 10 IUPAC lecturers from the Division VI’s Subcommittee on Crop Protection Chemistry, who highlighted the findings and recommendations of several IUPAC projects.1–7
Innovative Chemistry and Technology for Crop Protection
Increased agricultural production in Brazil and other Latin American countries will be critical to meet the world’s burgeoning requirements for food and fiber, and intensive investments in innovative research efforts will be required.
Gerry Stephenson of the University of Guelph, Canada, pointed out that the population of South America is expected to reach 500 million by 2050, and this increase will present significant challenges for increased efficiency of agricultural production. Pesticide use for management of insect, weed, and disease pests has played an important role in doubling the theoretical food crop yield experienced since 1965. Worldwide sales of agricultural pesticides have exceeded at least USD 20 billion per year since the 1990s. Unfortunately, 30 percent to 40 percent of the theoretical yield is still being lost today due to pest impacts, so additional efficiencies are required to continue to meet the world’s needs without bringing more of the world’s marginal lands into production. Stephenson noted that the increased efficiency derived from use of agricultural pesticides had, during the past half-century, saved conversion of one-half of today’s forested land to food production.
José Otavio Menten of ANDEF, Brazil, emphasized that pesticides are particularly relevant for tropical agriculture, where pest pressures are often experienced with greater frequency and more severity than in the temperate zone. He noted that agricultural production in Brazil recently had increased to the point where the country is now numbered among the top users of pesticide chemicals in the world. To continue to provide new and safer tools for pest management and stay ahead of pest resistance development, intensive R&D efforts are required. Introduction of one new chemical pesticide may involve screening of more than 200 000 candidate molecules and can take 10–12 years and an investment of USD 300 million for completion of development, safety, and environmental testing.
|Members of the IUPAC Subcommittee on Crop Protection Chemistry, including “Rio Organizers” (in front row, from left) Laura McConnell, Pedro Freitas, Irene Alleluia, and Ken Racke.|
Areas of emphasis for industrial R&D efforts were highlighted by Ken Racke of Dow AgroSciences, USA, and Keiji Tanaka of Mitsui Chemicals Agro, Japan. Racke noted that there has been an increased emphasis on developing pesticides with enhanced human safety and reduced environmental impact as part of a “reduced risk” initiative that originated in the USA in the mid–1990s. Based on a government-industry cooperation that accelerates regulatory evaluation and approval for successful candidates, nearly 50 new, reduced-risk active ingredients, including several biopesticides, have been introduced for agriculture in the USA and worldwide since 1994. Tanaka emphasized the efforts of industry in developing products that provide effective pest management with reduced environment loading (20–100 g/ha active ingredient instead of 1000–3000 g/ha) and with advanced formulation and delivery technologies that minimize worker exposures (e.g., water-soluble sachets or tablets in place of jugs of high-volume liquid products). Finally, Maria de Fátima Grossi de Sá of EMBRAPA, Brazil, highlighted new developments for employment of biotechnology and genetic engineering to agricultural pest management. Introduction of genetically modified cotton, soybeans, and maize has already resulted in a shift to more effective and environmentally compatible weed and insect management practices in Brazil and other countries.1,5 Research is now focused on new crops and pests, and Grossi de Sá highlighted ongoing efforts at EMBRAPA to develop crop plants engineered for resistance to soil nematode pests.
Risk Assessment, Regulation and Global Harmonization
Progress is being made toward the adoption of science-based and internationally-harmonized approaches to regulation of crop protection chemistry, but further efforts and increased Latin American participation is required.
Bernhard Johnen of CropLife International, Belgium, emphasized the principles of sound regulation and highlighted existing international treaties, conventions, and initiatives which provide the framework for harmonized approaches. Some of the most important principles include availability of a sound policy framework to ensure high standards of use and protection for human health and the environment, reliance on scientific principles and risk/benefit evaluation, and transparency of the regulatory process with clear roles defined for the various stakeholders.
Keith Solomon of the University of Guelph, Canada, outlined the importance of the risk assessment approach in the pesticide regulatory process. Risk assessment is a process of assigning magnitudes, probabilities, and relevance to the adverse effects that may result from a particular activity or set of activities and is critical in making correct decisions in evaluating new crop protection chemistry products and uses. Solomon emphasized the critical nature of integrating numerical estimates of toxicity, exposure, and the probability of exposure to support a more objective decision-making process.
The importance of adopting measures to ensure high-quality and reliable chemical and biological data for use in the regulatory evaluation process was emphasized by Elisa Rosa dos Santos of INMETRO, Brazil. Rosa dos Santos highlighted the “Good Laboratory Practices” or GLP system which was first developed for the pharmaceutical industry and more recently applied to the crop protection chemical industry. This intensive system of quality procedures, record-keeping, documentation, and independent auditing is applied to entire research facilities as well as to each individual study, and is increasingly being relied upon by the Brazilian regulatory authorities ANVISA, IBAMA, and MAPA.
|View of Rio Janeiro, site of the 3rd IUPAC International Workshop on Crop Protection Chemistry in Latin America.|
Recent progress for international harmonization of evaluation and regulation of crop protection chemistry was highlighted by several government and industry lecturers. Volker Bornemann of BASF Corp., Germany, highlighted the efforts of the Organization for Economic Cooperation and Development (OECD) in the elaboration of a harmonized set of guidelines for human safety and environmental testing, and noted very recent progress with a harmonized guideline for pesticide residue testing in food crops. Jeff Herndon of the U.S. Environmental Protection Agency (EPA) outlined an innovative program of joint evaluations for new pesticide active ingredients initiated during the past several years. The OECD joint evaluation allows a single dossier of core studies to be simultaneously evaluated in multiple, cooperating countries through a work-sharing arrangement. Final risk assessments and regulatory decisions are left to the participating countries, but the result has been more harmonized outcomes of the evaluation process. So far, primary participants in the OECD joint evaluations have included Australia, Canada, Germany, UK, and USA, but both Mexico and Brazil are becoming increasingly active.
Environmental Chemistry and Risk Assessment
The need for agricultural production must be balanced by protection of environmental resources, and this will be facilitated in Latin American countries by more widespread adoption of risk assessment-based approaches.
Environmental fate and ecological risk assessment were important areas of emphasis for the workshop, particularly in light of growing environmental awareness in the Latin American region. Lecturers highlighted advances in understanding pesticide fate in soil, water, and air. Jan Linders of the National Institute for Public Health and Environment, The Netherlands, highlighted simulation modeling advancements for prediction of surface and ground water levels of pesticides in agricultural catchments. Cathleen Hapeman of the U.S. Department of Agriculture (USDA) summarized field research approaches to estimate pesticide movement in runoff sediment and water and evaluation of potential mitigation practices. Laura McConnell, also of USDA, shared recent developments in modeling and monitoring the fate of pesticides and other volatile agricultural chemicals in air. She also highlighted conclusions of the critical evaluation of methodology now being completed as part of an IUPAC project.4
Lecturers also placed significant emphasis on the need for integration of environmental fate and effects information to support the risk assessment paradigm. Rafaela Maciel Rebelo of the Brazilian Institute of Environment and Renewable Natural Resources highlighted current regulatory evaluation approaches and future needs for Brazil. At present, environmental management of crop protection chemistry in Brazil is based on a hazard classification and scoring system. There is a future need to better employ the principles of environmental risk assessment (probability, exposure, effects) in supporting the regulation of pesticides in Latin American countries, and two lecturers highlighted recent case studies.
The first study, presented by Joseph Dulka of DuPont, USA, involved a cooperative project between the Colombian government and CropLife Latin America for development of a tiered evaluation scheme for predicting pesticide concentration and impacts in surface and ground water. Without the tiers, simple screening examinations tend to trigger the need for extensive field monitoring studies. Standardized evaluation scenarios based on representative soil, climate, and crop conditions for Colombia were developed by adapting available dissipation and transport models utilized in the USA and European Union. This approach allows the regulatory authorities to make more rapid, science-based decisions using available data rather than waiting for months or years for additional studies.
The second case study was presented by Keith Solomon of the University of Guelph, Canada. It involved a cooperative effort between the University of Guelph and Universidad del Tolima, Colombia, and focused on evaluation of potential nontarget amphibian effects associated with herbicidal management of illicit cocaine agriculture. Based on comparing distributions of aerial spray deposition patterns developed from wind tunnel experiments with differential sensitivity of various amphibian species noted from laboratory studies, it was determined that the probability of adverse effects for the vast majority of scenarios could be reduced to negligible levels by employing a five-meter spray buffer setback.
Pesticide Residues in Food and Human Exposure
The need for agricultural production must be balanced by protection of human health, with emphasis placed on measures to ensure safety of consumers exposed to trace levels in food.
Several lecturers brought attention to evaluation of pesticide residues in food, and noted that the primary means of local management of pesticide residues in food is via establishment of maximum residue limits or MRLs. The MRL is defined as the “Maximum concentration of a residue that is legally permitted or recognized as acceptable in, or on, a food, agricultural commodity or animal feedstuff as set by Codex or a national regulatory authority,”3 and is established for a particular pesticide/crop combination to reflect the trace residues to be expected when farmers follow Good Agricultural Practice and approved labeling. In Brazil and several other Latin American countries, the evaluation process includes development of field residue trials to estimate the MRL, and as explained by Eloisa Caldas of the University of Brasilia, a dietary risk assessment is prepared to confirm safety of these levels. Luiz Cláudio Meirelles of ANVISA, Brazil, described the post-registration monitoring, which is coordinated by 37 regional laboratories distributed within the agricultural areas of Brazil. As exports of high-value commodities have increased in recent years, the level of residue monitoring activities has also had to increase.
Adélia Cristina Pessoa Araújo of the Institute of Technology of Pernambuco, Brazil, noted that for fresh fruits, the state lab had increased the number of samples examined per year for as many as 400 pesticides from fewer than 500 samples in 2002 to more than 3000 samples in 2008. As emphasized by Phil Brindle of BASF Corp., USA, one continuing challenge faced by farmers, food exporters, and the chemical industry is the lack of global harmonization of MRL standards among countries. As pointed out by Luis Rangel of MAPA, Brazil, the problem is particularly acute for various minor crops such as tropical fruits (e.g., papaya, mango, starfruit), which are often not grown in countries in the temperate zone so tend to lack MRLs in important destination regions such as the EU, Japan, and North America. Caroline Harris of Exponent, Inc., UK, and Eloisa Caldas of the University of Brasilia both emphasized the importance of seeking greater national recognition of the international MRL standards established via the CODEX process.
Education and Information Management in Crop Protection
Adoption of sound evaluation approaches and good stewardship for the use of crop protection chemicals requires additional emphasis on education and training of regulatory authorities and farmers. In an era of information proliferation, there is a critical need for adoption of good information management practices including availability of up-to-date, electronic databases of pesticide properties.
The workshop included several lectures focused on education, training, and communication. Ron Parker of the U.S. EPA shared preliminary outcomes of an IUPAC project6 designed to promote widespread availability of tools and training for environmental risk assessment. The e-VALUATE tool is an internet-based, pesticide ecological risk assessment and training module developed with support from IUPAC, FAO, and U.S. EPA. Both English and Spanish versions of the module have been developed, and training sessions or seminars have already been held in several countries including China, Costa Rica, and India.
Learning approaches and options for use within the laboratory context were described by Elizabeth Carazo of the University of Costa Rica. In cooperation with the FAO and IAEA, an internet-based, e-training system for such important topics as analytical residue methods, GLP, safety, and laboratory accreditation has been made available.2 Training farmers and pesticide applicators for good stewardship practices was the subject of several lectures.
José Otavio Menten of ANDEF, Brazil, described industry efforts for promoting good product stewardship, which have included an emphasis on a “train the trainer” approach. He noted that during the past 20 years, around 32000 trainers had participated in 500 industry-sponsored educational events organized throughout Brazil. Courses and training have focused on such practical aspects as integrated pest management, safe transportation and storage practices, use of appropriate personal protective equipment and clothing during mixing and application, and good waste disposal practices.
With respect to protective clothing and equipment for pesticide handlers and applicators, Hamilton Humberto Ramos of the Agronomic Institute, Brazil, described improvement efforts of the past 20 years. Although Brazilian regulations dating from the late 1970s mandated the use of protective clothing, gloves, and respiratory devices, it has only been recently that his laboratory and others have developed quality standards for such materials and also sought to identify improved technologies. With respect to container disposal practices, Mário Kazuchira Fujii of the National Institute for Processing Empty Containers, Brazil, described the nationally mandated program of empty container recycling. Finally, John Unsworth, a consultant based in the UK, described the tremendous challenge for regulatory authorities, industry, and academia in managing the vast amount of information becoming available on crop protection chemistry. He described the internet-based system at http://agrochemicals.iupac.org, developed as the outcome of an ongoing IUPAC project.7 The website has centralized and organized access to key electronic crop protection chemistry information including the IUPAC pesticide glossary, regulatory requirements and testing guidelines, GLP practices, pesticide profiles, and training resources.
Outcomes and Future Plans
As a consequence of holding the workshop in Rio de Janeiro, five new members were recruited to join the work of the Subcommittee on Crop Protection Chemistry, including scientists from Brazil, Colombia, and Uruguay. IUPAC has historically struggled to maintain good participation from Latin America, and participation of these new members will greatly assist crop protection chemistry efforts of IUPAC. Also, new IUPAC project proposals are under development to address three areas of need identified at the workshop: 1) development of better methods for extrapolating data on the soil fate of pesticides from region-to-region, 2) elaboration of regional guidance for harmonized assessment methods for crop protection chemicals, and 3) better estimation of volatility and pesticide inhalation exposure to workers. Finally, a project was agreed for industry sponsorship to translate the IUPAC pesticide glossary3 and the noteworthy textbook Pesticides and the Environment8 into the Portuguese language.
The IUPAC workshop in Rio de Janeiro was the 9th in a series of such crop protection chemistry-related workshops organized by the Division VI since 1988 and the 3rd to be held in Latin America. Past workshops have been held in Brazil (1996), China (1988, 2007), Costa Rica (2005), Korea (2003), Taiwan (2000), and Thailand (1992). The DCE Subcommittee on Crop Protection Chemistry is now considering proposals for the next workshop, and welcomes input and suggestions from the worldwide IUPAC community.
Lecture presentation slides have been posted to the workshop website <www.iupacrio2009.org/presentations.html>.
- IUPAC Project 2001-024-2-600 (Kleter)
- IUPAC Project 2003-013-1-600 (Carazo)
- IUPAC Project 2004-002-1-600 (Stephenson); project outcome published in Pure Appl. Chem. 78(11), 2075–2154, 2006.
- IUPAC Project 2006-011-1-600 (McConnell)
- IUPAC Project 2006-015-3-600 (Kleter)
- IUPAC Project 2008-011-2-600 (Parker)
- IUPAC Project 2008-041-1-600 (Unsworth)
- Stephenson, G.R., and Solomon K.R. 2008. Pesticides and the Environment. Canadian Network of Toxicology Centres, University of Guelph, 425 pp. ISBN 978-0-9808847-0-8. www.uoguelph.ca/cntc/educat/pesticide
Ken Racke <email@example.com>, senior scientist with Dow AgroSciences in Indianapolis, USA, is past president of the IUPAC Division on Chemistry and the Environment, and has been active with the Subcommittee on Crop Protection Chemistry for several years. His interests include environmental impact assessment of pesticides, food safety standards for pesticide residues in food, and international harmonization of the regulation of crop protection chemistry.
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