The impact of pesticide residues on human health is a worldwide problem, as human exposure to pesticides can occur through ingestion, inhalation, and dermal contact. Regulatory jurisdictions have promulgated the standard values for pesticides in residential soil, air, drinking water, and agricultural commodity for years. Until now, more than 19,400 pesticide soil regulatory guidance values (RGVs) and 5400 pesticide drinking water maximum concentration levels (MCLs) have been regulated by 54 and 102 nations, respectively. Over 90 nations have provided pesticide agricultural commodity maximum residue limits (MRLs) for at least one of the 12 most commonly consumed agricultural foods. A total of 22 pesticides have been regulated with more than 100 soil RGVs, and 25 pesticides have more than 100 drinking water MCLs. This research indicates that those RGVs and MCLs for an individual pesticide could vary over seven (DDT drinking water MCLs), eight (Lindane soil RGVs), or even nine (Dieldrin soil RGVs) orders of magnitude. Human health risk uncertainty bounds and the implied total exposure mass burden model were applied to analyze the most commonly regulated and used pesticides for human health risk control. For the top 27 commonly regulated pesticides in soil, there are at least 300 RGVs (8% of the total) that are above all of the computed upper bounds for human health risk uncertainty. For the top 29 most-commonly regulated pesticides in drinking water, at least 172 drinking water MCLs (5% of the total) exceed the computed upper bounds for human health risk uncertainty; while for the 14 most widely used pesticides, there are at least 310 computed implied dose limits (28.0% of the total) that are above the acceptable daily intake values. The results show that some worldwide standard values were not derived conservatively enough to avoid human health risk by the pesticides, and that some values were not computed comprehensively by considering all major human exposure pathways.

To promote international collaboration on environmental pollution management and human health protection, we conducted a global-level study on the management of pesticides for surface freshwater quality. Prior to actions being taken in terms of water treatment or remediation, it is essential that clear and definite regulations be disseminated. In our study, 3094 surface freshwater quality standards for 184 different pesticides were recorded from 53 countries and categorized according to pesticide types and standard types, as well as diverse use of freshwater by humans, and compared water quality standards related to human health. Our results indicate large variations in pesticide regulations, standard types (i.e., long- or short-term water quality standards), and related numerical values. With regard to the protection of human health, the 10 most frequently regulated pesticides account for approximately 47% of the total number of standards across 184 considered pesticides. The average occurrence-weighted variations of standard values (i.e., numerical values provided in a standard in terms of residue limits of a given pesticide in water) for the 20 most regulated persistent organic pollutants (POPs) and other phase-out pesticides (i.e., pesticides not currently-approved for use in agriculture across various countries) are 4.1 and 2.6 orders of magnitude, respectively, with human-exposure related standard values for some pesticides varying with over 3 orders of magnitude (e.g., lindane). In addition, variations in water quality standard values occurred across standard types (e.g., maximum and average), water use types (e.g., unspecified waters and human consumption), and standard values (e.g., pesticide individuals and groups). We conclude that regulatory inconsistencies emphasize the need for international collaboration on domestic water treatment, environmental management as well as specific water quality standards for the wider range of current-use pesticides, thereby improving global harmonization in support of protecting human health.