Water Quality and Pesticide Concerns: Health and Policy Review

Introduction to Pesticides: Definitions and History

The U.S. Environmental Protection Agency (EPA) describes a "pesticide" as a substance or combination of substances intended for (1) the prevention, elimination, repulsion, or mitigation of any pest; (2) use as a plant regulator, defoliant, or desiccant; or (3) use as a nitrogen stabilizer. Although this formal definition is relatively recent, pesticides have been integral to agricultural production worldwide for centuries and have likely played an essential role in managing insects, weeds, and diseases.

For example, sulfur's use for controlling plant diseases can be traced back 4,500 years to its first application in Sumeria. Mercury and arsenic salts were later introduced, and the insecticidal properties of chrysanthemum flower extracts (pyrethrum) were discovered approximately 2,000 years ago. Indeed, natural substances have long been employed to help manage pests in agriculture (Reeves et al., 2019).

Contemporary Uses of Pesticide-Classified Substances

Many substances used daily are classified as pesticides if marketed for their pest-mitigating abilities. Disinfecting agents serve as a typical example — products containing bleach that are promoted for their capacity to manage pathogens must be registered with the EPA as pesticides. Boric acid, often used as a whitening agent in laundry, is also registered as a pesticide for insect control. Vitamin D3 (cholecalciferol), an essential nutrient, is likewise registered as a pesticide. When ingested in large amounts, vitamin D3 can be lethal to rats and mice, and products containing vitamin D3 designed for this purpose must be registered with the EPA as rodenticides (Reeves et al., 2019).

Exposure Assessment and Environmental Justice

Increased pesticide exposure typically falls on the poorest and most vulnerable populations globally. This is also true in the United States, where pesticide exposure strongly correlates with race, ethnicity, and socioeconomic status. The following sections examine general trends in exposure across different subpopulations in the United States and identify specific demographic groups that disproportionately bear the societal burdens of pesticide use (Donley et al., 2022).

Researchers from California's Environmental Protection Agency identified pesticide usage as the most significant pollution burden contributing to racial, ethnic, and income disparities in the state, surpassing various air pollutants and other toxic releases. Their findings indicated that most pesticide applications in California occurred within the 60% of zip codes with the highest proportion of people of color. Additional research revealed that over half of the glyphosate applied in California was utilized in the state's eight poorest counties, where 53% of inhabitants identified as Hispanic or Latinx — compared to the statewide average of 38%.

In 2019, pesticides totaling over eight million pounds that are associated with childhood cancers were applied in 11 Californian counties with a predominantly Latinx population (greater than 50%), equating to 4.2 pounds of these pesticides per individual. Conversely, 770,000 pounds of the same pesticides were applied in 25 Californian counties with the lowest Latinx population (less than 24%), resulting in only 0.35 pounds per person. Both county groups have comparable land areas and total populations (Donley et al., 2022).

National patterns also reflect these disparities. African Americans and Mexican Americans have greater pesticide indicators in their bloodstream or urine compared to non-Hispanic whites not living in poverty. Similarly, the largest gap between white women and women of color across 16 chemical categories tested was observed in pesticide exposure markers. A study conducted by the U.S. Centers for Disease Control and Prevention (CDC) found that specific historical pesticide byproducts were more prevalent in Mexican American and African American women aged 40 and older than in white women. Non-Hispanic Black and Mexican American individuals also disproportionately experienced the financial and health effects linked to organophosphate pesticide exposure compared to non-Hispanic white individuals (Tessum et al., 2021).

To analyze a broader array of pesticides across the country, researchers examined data gathered by the CDC for the Report on Human Exposure to Environmental Chemicals. This document includes data on various pesticides and their byproducts tracked in the blood and urine of a nationally representative U.S. population sample from 1999 to 2016. Among 14 pesticides and byproducts with concentrations high enough to establish a geometric mean for the three demographic subgroups studied — non-Hispanic white, non-Hispanic Black, and Mexican American — only 3 (21%) were detected in non-Hispanic whites at levels above the overall population average. In contrast, average urinary and serum concentrations were elevated for 8 of 14 (57%) pesticides and byproducts in non-Hispanic Blacks, and for 10 of 14 (71%) in Mexican Americans, compared to the national average. For 12 out of 14 pesticides and byproducts evaluated, non-Hispanic Blacks or Mexican Americans displayed higher average concentrations than non-Hispanic whites (Tessum et al., 2021).

Conclusion

Governments play a crucial role in decreasing pesticide usage and associated risks. Major challenges for effective policy implementation include updating regulations specific to agricultural pesticides, strictly enforcing existing laws, strengthening the function and clarifying the role of agricultural extension services responsible for translating government policies to farmers, raising farmer awareness of pesticide safety measures and alternative pest management, implementing incentive policies that promote alternative pest management, and educating consumers about pesticide risks and how to make safer food choices. All of these approaches should be implemented simultaneously and without delay.

Governments must also collaborate with other sectors — including agriculture, health, the environment, and private and food industries. Such cooperation results in sustainable problem-solving and meaningfully reduces both pesticide use and risk (Sharma et al., 2019).

References

Reeves, W. R., McGuire, M. K., Stokes, M., and Vinci, J. L. (2019). Assessing the safety of pesticides in food: How current regulations protect human health. American Society for Nutrition, 10, 80–88.

Tessum, C. W., Paolella, D. A., Chambliss, S. E., Apte, J. S., Hill, J. D., and Marshall, J. D. (2021). PM 2.5 polluters disproportionately and systemically affect people of color in the United States. Science Advances, 7, eabf4491.

Donley, N., Bullard, R. D., Economos, J., Figueroa, I., Lee, J., Liebman, A. K., Martinez, D. N., and Shafiei, F. (2022). Pesticides and environmental injustice in the USA: Root causes, current regulatory reinforcement and a path forward. BMC Public Health, 22, 708.

Policy Department for External Relations (PDER). (2021). The use of pesticides in developing countries and their impact on health and the right to food. Directorate General for External Policies of the Union. PE 653.622 — January 2021.

Sapbamrer, R., Kitro, A., Panumasvivat, J., and Assavanopakun, P. (2023). Important role of the government in reducing pesticide use and risk sustainably in Thailand: Current situation and recommendations. Frontiers in Public Health, 11, 1141142.

Sharma, A., Kumar, V., Shahzad, B., Tanveer, M., Sidhu, G. P. S., Handa, N., et al. (2019). Worldwide pesticide usage and its impacts on ecosystem. SN Applied Sciences, 1, 1446.