An Occupational Heat Stress and Hydration Assessment of Agricultural Workers in North Mexico

Abstract

Expanding agribusiness in Northern Mexico has increased demand for workers from Southern Mexico, with hundreds of thousands migrating for work annually. Extreme temperatures, physical labor, and low fluid consumption place workers at risk for heat strain and dehydration, commonly underreported hazards in the agricultural industry. The objectives of this pilot study were to assess heat exposure and hydration status of a population of migratory agricultural workers in Northern Mexico throughout the grape harvest season. In addition to demographic information, environmental conditions, hydration status, and core body temperatures were collected. The majority listed Chiapas as their home state, nearly half spoke an Indigenous language, and none had completed high school. The wet-bulb globe temperature was significantly higher during the harvest and post-harvest seasons compared to the pre-harvest season. Across the different seasons, the majority were dehydrated post-shift, and mean core body temperature of workers was not significantly different. This project highlights the need for targeted interventions to improve hydration and prevent heat stress in this region. As the number of warm days is expected to rise each year worldwide, it will be increasingly important to engage in practices to protect vulnerable populations, such as migratory agriculture workers.

Keywords: climate change; dehydration; farm worker; heat strain; thermal stress.

Figure 1

American Conference of Governmental Hygienists Threshold Limit Value and Action Limit for heat stress by month (n = 28).

Figure 2

Comparison of specific gravity quartiles by month and collection time (n = 28).

Figure 3

Worker core body temperature during workday, by temperature range (n = 24).