13th IUPAC International Congress of Pesticide Chemistry: Crop, Environment, and Public Health Protection, Technologies for a Changing World.

This introductory paper provides an overview of Perspectives papers written by plenary speakers from the 13th IUPAC International Congress of Pesticide Chemistry held in San Francisco, CA, USA, in August 2014. This group of papers emphasizes some of the emerging issues and challenges at the forefront of agricultural research: sustainability; agriculture's response to climate change and population growth; pollinator health and risk assessment; and global food production and food security. In addition, as part of the Congress, a workshop on "Developing Global Leaders for Research, Regulation, and Stewardship of Crop Protection Chemistry in the 21st Century" identified specific recommendations to attract the best scientists to agricultural science, to provide opportunities to study and conduct research on crop protection chemistry topics, and to improve science communication skills.

Altered pesticide use on transgenic crops and the associated general impact from an environmental perspective.

The large-scale commercial cultivation of transgenic crops has undergone a steady increase since their introduction 10 years ago. Most of these crops bear introduced traits that are of agronomic importance, such as herbicide or insect resistance. These traits are likely to impact upon the use of pesticides on these crops, as well as the pesticide market as a whole. Organizations like USDA-ERS and NCFAP monitor the changes in crop pest management associated with the adoption of transgenic crops. As part of an IUPAC project on this topic, recent data are reviewed regarding the alterations in pesticide use that have been observed in practice. Most results indicate a decrease in the amounts of active ingredients applied to transgenic crops compared with conventional crops. In addition, a generic environmental indicator -- the environmental impact quotient (EIQ) -- has been applied by these authors and others to estimate the environmental consequences of the altered pesticide use on transgenic crops. The results show that the predicted environmental impact decreases in transgenic crops. With the advent of new types of agronomic trait and crops that have been genetically modified, it is useful to take also their potential environmental impacts into account.

Disposal and degradation of pesticide waste.

Generation of pesticide waste is inevitable during every agricultural operation from storage to use and equipment cleanup. Large-scale pesticide manufacturers can afford sophisticated recovery, treatment, and cleanup techniques. Small-scale pesticide users, for example, single farms or small application businesses, struggle with both past waste problems, including contaminated soils, and disposal of unused product and equipment rinsewater. Many of these problems have arisen as a result of inability to properly handle spills during, equipment loading and rinsewater generated after application. Small-scale facilities also face continued problems of wastewater handling. Old, obsolete pesticide stocks are a vexing problem in numerous developing countries. Pesticide waste is characterized by high concentrations of a diversity of chemicals and associated adjuvants. Dissipation of chemicals at elevated concentrations is much slower than at lower concentrations, in part because of microbial toxicity and mass transfer limitations. High concentrations of pesticides may also move faster to lower soil depths, especially when pore water becomes saturated wish a compound. Thus, if pesticide waste is not properly disposed of, groundwater and surface water contamination become probable. The Waste Management Hierarchy developed as an Australian Code of Practice can serve as a guide for development of a sound waste management plan. In order of desirability, the course of actions include waste avoidance, waste reduction, waste recycling, waste treatment, and waste disposal. Proper management of pesticide stocks, including adequate storage conditions, good inventory practices, and regular turnover of products,. will contribute to waste avoidance and reduction over the long-term. Farmers can also choose to use registered materials that have the lowest recommended application rates or are applied in the least volume of water. Wastewater that is generated during equipment rinsing can be recycled by spraying it onto cropland, thus avoiding a soil contamination problem. If it is not feasible to spray out rinsates, then water treatment becomes necessary. However, for small waste generators, practical technology is still too experimental and not easily implemented on an individual farm or at a small application business. Nevertheless, research has been quite active in application of advanced oxidation processes (UV/ozonation: photoassisted Fenton reaction: photocatalysis using TiO2). Obsolete pesticide stocks in developing countries are being packaged and shipped to developed countries for incineration. Contaminated soil can also be incinerated, but this is not practical nor affordable for small waste generators. Chemical degradation of chlorinated hydrocarbon pesticides may be amenable to dechlorination by alkali polyethylene glycol treatment, but further study is needed to make the technique practical for small waste generators. Contaminated soils may be amenable to cleanup by one of several biological treatment methods, including composting, landfarming, and bioaugmentation/ biostimulation. Composting and landfarming (which may be used in combination with biostimulation) may be the most practical of the biological methods that is immediately ready for implementation by small-scale pesticide waste generators.