4. Conclusion
The use of OPs as insecticides in the agricultural and urban settings is still high and is expected to remain so, at least in the near future. While other classes of insecticides are gaining market share (e.g., pyrethroids) and new classes have been developed (e.g., neonicotinoids), the efficacy of OPs, their relatively low cost and their lack of bioaccumulation in the ecosystems, would support this prediction. Yet OPs display relatively limited selectivity (one exception may be malathion) between insects and non target species, including humans. As such, concerns on their potential adverse effects in human populations will continue. The issues discussed in the review still represent real-life problems, with clinical, societal and legal ramifications. Continuing research in all these areas, and others not mentioned, is welcome and warranted.