Stress, Mental Health, and Coping Among Workers in the Northern California Cannabis Industry: A Qualitative Descriptive Analysis

California is home to a multibillion-dollar cannabis (marijuana) industry, but little is known about the occupational health and safety hazards faced by cannabis workers and even less of the stress, mental health, and coping mechanisms among these workers. Previous research has been based on long-term workers at legal businesses, but most California cannabis is produced and sold unlawfully. There are many seasonal workers whose experiences have not been studied. A qualitative study based on focus group discussions and key informant interviews was performed to understand cannabis workers' experiences, knowledge, and perceptions of occupational hazards. Participants reported sources of stress including production pressure and isolation, and mental health outcomes such as depression and mental fatigue. They described primarily maladaptive coping mechanisms. Unique characteristics of the cannabis industry, including criminalization and isolated, remote farms, make interventions challenging. However, policy approaches that involve community organizations could promote worker health.

How Does Environmental Temperature Affect Farmworkers' Work Rates in the California Heat Illness Prevention Study?

OBJECTIVE

Estimate the association between environmental temperature (wet bulb globe temperature [WBGT]) and work rate over the course of a workday.

METHODS

Repeated-measures regression was used to identify characteristics impacting work rate in a cross-sectional study of Latino farmworkers. Minute-by-minute work rate (measured by accelerometer) and WBGT were averaged over 15-minute intervals.

RESULTS

Work rate decreased by 4.34 (95% confidence interval [CI], -7.09 to -1.59) counts per minute per degree Celsius WBGT in the previous 15-minute interval. Cumulative quarter hours worked (2.13; 95% CI, 0.82 to 3.45), age (-3.64; 95% CI, -4.50 to -2.79), and dehydration at the end of workday (51.37; 95% CI, 19.24 to 83.50) were associated with counts per minute as were gender, pay type (piece rate vs hourly) and body mass index ≥25 kg/m 2 . The effects of pay type and body mass index were modified by gender.

CONCLUSION

Increased temperature was associated with a decrease in work rate.

California cannabis cultivation and processing workers: A qualitative analysis of physiological exposures and health effects

INTRODUCTION

Cannabis is a multi-billion-dollar California industry, but little is known about the occupational hazards or health experiences of cannabis cultivation workers. Respiratory and dermal exposures, musculoskeletal hazards, and other agricultural hazards have been identified in previous research. Even in a post-legalization framework, cannabis work is stigmatized and most cannabis is still produced illegally. Qualitative research is essential for establishing rapport with cannabis workers to understand their experiences and concerns.

METHODS

We conducted semi-structured discussions with four focus groups including 32 cannabis workers total, and 9 key informants who were workers, industry experts, and business owners or managers. Transcribed results were analyzed to identify key themes on physiological exposures and health effects.

RESULTS

The majority (81.3%) of focus group participants were seasonal migrant cannabis trimmers. Themes emerged of respiratory and dermal exposures and outcomes, musculoskeletal disorders, and physical hazards including living conditions. Workers reported respiratory symptoms and rashes from exposure to cannabis, mold, and pesticides. Musculoskeletal pain was ubiquitous due to inadequate seating and long shifts performing repetitive tasks. Seasonal workers experienced chronic exposure to cold conditions and unsanitary housing. Management-level interviewees and other industry stakeholders described concerns and experiences that differed from those of workers.

DISCUSSION

The results were consistent with existing research on cannabis worker health, with workers reporting respiratory and dermal exposure and symptoms, musculoskeletal hazards, and physical hazards associated with agricultural work. In addition, we found that workers were affected by substandard living conditions, remote and isolated work environments, and an absence of training.

A Pilot Study of Respiratory and Dermal Symptoms in California Cannabis Cultivation Workers

Cannabis (Cannabis sativa, marijuana) is the largest cash crop in California. While it is difficult to characterize the size of the industry, the total production is estimated at 15 to 16 million pounds per year, with total revenues exceeding $10 billion per year. Despite the huge size and rapid growth of the industry, there has been little research on the health and safety of cannabis workers. The goal of this pilot study was to explore the feasibility of collecting cannabis worker health data with a self-administered survey and to analyze the first systematically collected data on occupational health symptoms among California cannabis cultivation workers. We performed a cross-sectional survey of demographic and job characteristics as well as eye, nasal, respiratory, and dermal symptoms among 29 workers at two cannabis farms in the Sacramento area, California. Most participants were men aged less than 30 years, with 48% of participants self-identifying as non-Hispanic white and 58% reporting at least some college education. The most frequently reported work-related symptom was nasal irritation, and 38% of the participants reported symptoms suggestive of asthma. The participants had a demographic makeup distinct from traditional California agricultural workers, and a very high prevalence of current use of cannabis (93%). The high proportion of respondents with symptoms suggestive of asthma raises concern; sensitization to the cannabis plant has been reported among cannabis workers and users and there are many well-documented agricultural exposures causing asthma and asthma-like syndrome.

Chronic disease burden among Latino farmworkers in California

Farmworkers are an essential workforce to maintain California's extensive agricultural production. However, this mostly Latino, immigrant population is affected by high poverty rates and food insecurity, which increases their risk of chronic diseases. We analyzed clinical and interview data from three studies of Latino farmworkers in California: (1) the Mexican Immigration to California: Agricultural Safety and Acculturation (MICASA) study, (2) the PASOS SALUDABLES pilot intervention (PASOS Pilot), and (3) the PASOS Study, a cluster-randomized, controlled trial (PASOS RCT). We aimed to determine the prevalence of diet-related chronic health outcomes (obesity, elevated waist circumference, high blood pressure, and high total cholesterol) and identify sociodemographic and socioeconomic factors associated with these conditions in this population. A total of 1,300 participants were included in this study (452 from MICASA, 248 from PASOS Pilot, and 600 from PASOS RCT). Obesity prevalence ranged from 29.2 to 54.5% across samples; elevated waist circumference was observed in 29.4-54.0% of participants; high blood pressure was detected in 42.0-45.5% of participants; 23.7-25.8% of participants had high total cholesterol. Age was positively associated with each health outcome, although not for each sample; each additional year in age increased odds by 3-9%, depending on the outcome and sample. Females were at higher risk of obesity (one sample) and elevated waist circumference, but at lower risk of high blood pressure and high total cholesterol. Single, divorced or widowed participants (vs. married/living together) had 35 and 47% reduced odds of obesity and elevated waist circumference, respectively. Each additional year living in the US was associated with 3-6% increased odds of obesity, depending on the sample. Higher household income was associated with a reduction in odds of high total cholesterol up to 76% (one sample). These findings highlight the increased risk of chronic health conditions in Latino farmworkers, in particular for obesity, and among farmworkers who may lack access to health care, which represents a large proportion of this population. Differences in chronic health risks by sex suggest that clinical and public health responses might need to be sex-specific. Expansion of eligibility for supplemental nutrition programs for this low-income population could reduce their disease burden.

Anemia, Weight Status, and Fatigue Among Farmworkers in California: A Cross-Sectional Study

OBJECTIVE

This study aimed to determine the prevalence of anemia and overweight/obesity and assess the relationships between hematocrit (Hct) and body mass index (BMI), and between fatigue and Hct, among a sample of farmworkers in California.

METHODS

We estimated the prevalence of anemia (using Hct), overweight/obesity (BMI ≥25 kg/m 2 ), and self-reported fatigue in 587 farmworkers. Multivariable linear and logistic regression models were used to examine the associations between Hct and BMI, and between fatigue and Hct.

RESULTS

Anemia prevalence was 3.1%, overweight/obesity prevalence was 80.7%, and 78% of workers reported fatigue at work. There was no association between Hct and BMI or between Hct and reported fatigue. Women were more likely than men to have lower Hct and higher BMI.

CONCLUSIONS

A majority of farmworkers in this sample were overweight/obese, but anemia was uncommon. Anemia among more vulnerable subgroups of farmworkers should be explored.

Are Cal/OSHA Regulations Protecting Farmworkers in California From Heat-Related Illness?

OBJECTIVE

Determine compliance with and effectiveness of California regulations in reducing farmworkers' heat-related illness (HRI) risk and identify main factors contributing to HRI.

METHODS

In a cross-sectional study of Latino farmworkers, core body temperature (CBT), work rate, and environmental temperature (WBGT) were monitored over a work shift by individual ingestible thermistors, accelerometers, and weather stations, respectively. Multiple logistic modeling was used to identify risk factors for elevated CBT.

RESULTS

Although farms complied with Cal/OSHA regulations, worker training of HRI prevention and hydration replacement rates were insufficient. In modeling (AOR [95% CI]) male sex (3.74 [1.22 - 11.54]), WBGT (1.22 [1.08 - 1.38]), work rate (1.004 [1.002 - 1.006]), and increased BMI (1.11 [1.10 - 1.29]) were all independently associated with elevated CBT.

CONCLUSION

Risk of HRI was exacerbated by work rate and environmental temperature despite farms following Cal/OSHA regulations.

Migrant workers, essential work, and COVID-19

Globally, migrant and immigrant workers have borne the brunt of the COVID-19 pandemic as essential workers. They might be a Bulgarian worker at a meat processing plant in Germany, a Central American farmworker in the fields of California, or a Filipino worker at an aged-care facility in Australia. What they have in common is they are all essential workers who have worked throughout the coronavirus pandemic and have been infected with coronavirus at work. COVID-19 has highlighted the inequitable working conditions of these workers. In many instances, they are employed precariously, and so are ineligible for sick leave or social security, or COVID-19 special payments. If these are essential workers, they should get at least the same health and safety benefits of all nonessential workers. Improving the working and living conditions of migrant workers can and should be a positive outcome of the coronavirus pandemic.

Examining the Impact of Two Dimensions of Precarious Employment, Vulnerability and Insecurity on the Self-Reported Health of Men, Women and Migrants in Australia

Precarious employment is increasing and adversely affects health. We aimed to investigate how perception of precariousness in current employment impacts gender and migrant workers in Australia. Using cross-sectional interviews of 1292 workers born in Australia, New Zealand, India and the Philippines, data were collected on self-reported health, employment conditions and sociodemographics. Factor analysis of nine questions about perceptions of current employment revealed two dimensions, vulnerability and insecurity. Women had higher vulnerability scores (µ = 6.5 vs. µ = 5.5, t = 5.40, p-value (p) < 0.000) but lower insecurity scores (µ = 8.6 vs. µ = 9.3 t = −4.160 p < 0.0003) than men. Filipino-born workers had higher vulnerability compared with other migrant workers (µ = 6.5 vs. µ = 5.8 t = −3.47 p < 0.0003), and workers born in India had higher insecurity compared with other migrant workers (µ = 9.8 vs. µ = 8.9, t = −6.1 p < 0.0001). While the prevalence of insecurity varied by migrant status, the negative effect on health was higher for Australian-born workers than migrants. Increasing levels of vulnerability and insecurity impacted self-reported health negatively (Coefficient (Coef).0.34 p < 0.0001; Coef.0.25 p < 0.0001, respectively). The combination of high vulnerability and high insecurity had the greatest impact on health (Coef. 2.37 p = 0.002), followed by high vulnerability and moderate insecurity (Coef. 2.0 p = 0.007). Our study suggests that understanding both changes in employment conditions over time as well as knowledge of cultural patterns may offer the best chance of understanding the impact of precarious employment experiences.

Gender differences in respiratory health outcomes among farming cohorts around the globe: findings from the AGRICOH consortium

Purpose: Respiratory hazards of farming have been identified for centuries, with little focus on gender differences. We used data from the AGRICOH consortium, a collective of prospective cohorts of agricultural workers, to assess respiratory disease prevalence among adults in 18 cohorts representing over 200,000 farmers, farm workers, and their spouses from six continents.Methods: Cohorts collected data between 1992 and 2016 and ranged in size from 200 to >128,000 individuals; 44% of participants were female. Farming practices varied from subsistence farming to large-scale industrial agriculture. All cohorts provided respiratory outcome information for their cohort based on their study definitions. The majority of outcomes were based on self-report using standard respiratory questionnaires; the greatest variability in assessment methods was associated with chronic obstructive pulmonary disease (COPD).Results: For all three respiratory symptoms (cough, phlegm, and wheeze), the median prevalence in men was higher than in women, with the greatest difference for phlegm (17% vs. 10%). For asthma, women had a higher prevalence (7.8% vs 6.5%), with the difference associated with allergic asthma. The relative proportion of allergic asthma varied among cohorts. In two of eight cohorts for women and two of seven cohorts for men, allergic asthma was more common than non-allergic asthma.Conclusions: These findings indicate that respiratory outcomes are common among farmers around the world despite differences in agricultural production. As women in the general population are at higher risk of asthma, exploring gender differences in occupational studies is critical for a deeper understanding of respiratory disease among agricultural workers.

Impacts of weather, work rate, hydration, and clothing in heat-related illness in California farmworkers

BACKGROUND

The primary aim of this study was to investigate the effects of work rate, hydration status, and clothing on core body temperature (CBT) on California farmworkers.

METHODS

Two hundred and eighty-seven farmworkers were recruited in Summer 2015, with 259 participants having sufficient data for analysis. We collected CBT, ambient temperature, work rate, body weight loss, and clothing worn by each participant throughout the work day and demographic data from a questionnaire.

RESULTS

Multiple regression with CBT as the outcome was used to determine the adjusted associations between CBT, environmental heat load, and worker characteristics. The multivariate regression model showed statistically significant associations of CBT with work rate (β = .006, 95% CI [0.004, 0.009]) and wet-bulb globe temperature (β = .03, 95% CI [0.017, 0.05]).

CONCLUSION

Results suggest that among our population workload is the primary modifiable risk factor for heat-related illness. As expected, the ambient temperature was also associated with higher risk.

Physical activity and common tasks of California farm workers: California Heat Illness Prevention Study (CHIPS)

Farm workers are at risk of heat related illness (HRI), but their work rates that contribute to HRI have not been objectively assessed. The CHIPS study collected accelerometer data and characterized the physical activity of major farm tasks. Demographic information, work characteristics, and accelerometer data were collected from 575 farm workers in California. Each participating worker contributed measurements over one work shift. An Actical accelerometer was attached securely to a belt worn at the hip. Data were collected at one-minute intervals throughout the work shift. A total of 13 major work-task categories were defined. The mean physical activity counts per minute (cpm) and percentage of the shift spent at moderate and/or vigorous levels of activity were described for each task. Multiple linear regression models were constructed to determine the worker and environmental characteristics contributing to the physical activity level. Mean levels of physical activity ranged from 700 cpm (workers who carry produce) to a low of 150 cpm "ground pruners" who tend low-level plants, with an overall mean of 345 cpm or "light" activity (2 to ≤3 metabolic equivalents). The environmental temperature was the major factor associated with physical activity. A 10°C increase in the median temperature reduced the mean cpm by 135 (95% CI = 87, 193). Age and the tasks of sorting, ground pruning, and harvesting low-level crops were also negatively and independently associated with mean cpm. Incentivized (piece rate) pay, multi-task work, and irrigator work were positively associated with cpm. An interaction was found between piece rate and sex. Men's activity significantly increased (p < 0.001) by a mean of 95 cpm, (95% CI = 38.3, 150.7) if they were paid by the piece, but there was a non-significant association with women's activity level. Workers conducting multiple tasks, irrigators, men, and those earning incentivized (piece rate) pay had higher adjusted mean physical activity levels and are likely at increased risk of heat-related illness on hot days.

Protocol for a cluster randomized controlled trial to study the effectiveness of an obesity and diabetes intervention (PASOS) in an immigrant farmworker population

BACKGROUND

Studies have shown that the prevalence of overweight, obesity and diabetes are higher in the largely Hispanic, immigrant farmworker population in California. Though to date, few interventional studies have focused on these issues in this at-risk population. The objective of this paper is to describe the study design of a cluster randomized controlled trial aimed at evaluating the effectiveness of an obesity and diabetes work place intervention in an immigrant farm worker population.

METHODS

PASOS is an obesity and diabetes intervention program that will be implemented on ranches where immigrant farmworkers spend a considerable amount of time each day. This cluster randomized controlled study will enroll approximately 600 farmworkers. Using a uniform distribution for random number generation, ranches are randomized using a 1:1 ratio as either control or intervention. Baseline data will be taken from eligible participants and analyzed against data collected at the post-intervention, 6-month, 1-year, and 1.5-year follow-ups. The enrollment period is 1.5 years.

DISCUSSION

Few studies have been conducted that aim to evaluate the effectiveness of a worksite intervention for obesity and diabetes prevention in a largely Hispanic, farmworker population. This study has been tailored to this population in order to enhance the feasibility of implementation and retention. If successful in reducing obesity and increasing healthy lifestyle choices to reduce diabetes, this study design can be implemented on a larger scale.

TRIAL REGISTRATION

NCT02480244 . Registered 24 June 2015.

Personal exposure of dairy workers to dust, endotoxin, muramic acid, ergosterol, and ammonia on large-scale dairies in the high plains Western United States

Dairy workers experience a high degree of bioaerosol exposure, composed of an array of biological and chemical constituents, which have been tied to adverse health effects. A better understanding of the variation in the magnitude and composition of exposures by task is needed to inform worker protection strategies. To characterize the levels and types of exposures, 115 dairy workers grouped into three task categories on nine farms in the high plains Western United States underwent personal monitoring for inhalable dust, endotoxin, 3-hydroxy fatty acids (3-OHFA), muramic acid, ergosterol, and ammonia through one work shift. Eighty-nine percent of dairy workers were exposed to endotoxin at concentrations exceeding the recommended exposure guidelines (adjusted for a long work shift). The proportion of workers with exposures exceeding recommended guidelines was lower for inhalable dust (12%), and ammonia (1%). Ergosterol exposures were only measurable on 28% of samples, primarily among medical workers and feed handlers. Milking parlor workers were exposed to significantly higher inhalable dust, endotoxin, 3-OHFA, ammonia, and muramic acid concentrations compared to workers performing other tasks. Development of large modern dairies has successfully made progress in reducing worker exposures and lung disease prevalence. However, exposure to endotoxin, dust, and ammonia continues to present a significant risk to worker health on North American dairies, especially for workers in milking parlors. This study was among the first to concurrently evaluate occupational exposure to assayable endotoxin (lipid A), 3-hydroxy fatty acids or 3-OHFA (a chemical measure of cell bound and noncell-bound endotoxins), muramic acid, ergosterol, and ammonia among workers on Western U.S. dairies. There remains a need for cost-effective, culturally acceptable intervention strategies integrated in OHS Risk Management and production systems to further optimize worker health and farm productivity.

Recruitment, Methods, and Descriptive Results of a Physiologic Assessment of Latino Farmworkers: The California Heat Illness Prevention Study

OBJECTIVE

The California heat illness prevention study (CHIPS) devised methodology and collected physiological data to assess heat related illness (HRI) risk in Latino farmworkers.

METHODS

Bilingual researchers monitored HRI across a workshift, recording core temperature, work rate (metabolic equivalents [METs]), and heart rate at minute intervals. Hydration status was assessed by changes in weight and blood osmolality. Personal data loggers and a weather station measured exposure to heat. Interviewer administered questionnaires were used to collect demographic and occupational information.

RESULTS

California farmworkers (n = 588) were assessed. Acceptable quality data was obtained from 80% of participants (core temperature) to 100% of participants (weight change). Workers (8.3%) experienced a core body temperature more than or equal to 38.5 °C and 11.8% experienced dehydration (lost more than 1.5% of body weight).

CONCLUSIONS

Methodology is presented for the first comprehensive physiological assessment of HRI risk in California farmworkers.

Acculturation-related predictors of very light smoking among Latinos in California and nationwide

The prevalence of light smoking has increased among Latinos. The purpose of this study was to identify demographic and acculturation-related factors associated with very light smoking, defined as smoking 1-5 cigarettes per day (CPD), among Latinos in California and nationwide. Latino smokers in the 2007-2008 National Health and Nutrition Examination Survey (NHANES) or the 2009 California Health Interview Survey (CHIS) were analyzed. Logistic regression assessed factors associated with very light smoking. Among NHANES smokers, those born in Mexico or who lived fewer years in the US were more likely to be very light smokers than 6+ CPD smokers. Among CHIS smokers, those born in Mexico, in another Spanish speaking country, or who spent smaller percentages of their life in the US were more likely to be very light smokers. Findings from this study can be used to design tobacco control media campaigns that include very light smokers.

Hired farmworkers in the US: Demographics, work organisation, and services

OBJECTIVE

Farm work is labor-intensive, physically demanding, and incurs a high risk of injury. The aim of this study was to identify characteristics of farmworkers at increased risk of adverse health outcomes to focus targeted interventions.

METHODS

The National Agricultural Workers Survey for 2008-2012 was used to compare characteristics associated with adverse health and safety conditions among US-born and Mexican and Central American-born Latino and Indigenous, documented and undocumented farmworkers, separately for males and females.

RESULTS

US-born farmworkers had more secure work, worked less onerous tasks, and earned more per hour than other categories of farmworkers. Undocumented Indigenous workers had more precarious work, worked more onerous tasks, and were more likely to do piece work, than undocumented Latino workers.

DISCUSSION

We highlight disparities in modifiable occupational health risk factors across groups of farmworkers that are associated with increased risks of work-related injury and poor health. Am. J. Ind. Med. 59:644-655, 2016. © 2016 Wiley Periodicals, Inc.

Systematic review of respiratory health among dairy workers

The dairy industry is changing on a global scale with larger, more efficient operations. The impact of this change on worker health and safety, specifically, associations between occupational lung disease and inhalation exposures, has yet to be reported in a comprehensive review of the scientific literature. Therefore, a three-tier process was used to identify information using a keyword search of online databases of scientific literature. Of the 147 citations reviewed, 52 met initial screening criteria, and 30 were included in this review. Dairy workers experience lung conditions such as asthma, chronic obstructive pulmonary disease, hypersensitivity pneumonitis, chronic bronchitis, and cancer. Recent pulmonary function studies have identified obstructive lung changes among dairy farm workers. The increased scale of dairy production with significant changes in technology and work practices has altered inhalation exposure patterns among dairy workers. The inhalation exposure in the dairy work environment may elicit differing inflammatory responses in relation to timing of initial exposure as well as to repeated exposures. Few studies have measured inhalation exposure while simultaneously assessing the impact of the exposure on lung function of dairy farm workers. Even fewer studies have been implemented to assess the impact of aerosol control technology to reduce inhalation exposure. Future research should evaluate worker exposure to aerosols through a task-based approach while utilizing novel methods to assess inhalation exposure and associated inflammatory responses. Finally, potential solutions should be developed and tested to reduce inhalation exposure to inflammatory agents and respiratory diseases in the dairy farm work environment.

Region of birth, sex, and reproductive health in rural immigrant latino farmworkers: the MICASA study

PURPOSE

Characterize sexual and reproductive health among immigrant Latino farmworkers.

METHODS

We surveyed 806 immigrant Latino farmworkers from Mexico and Central America in a rural agricultural community in California's Central Valley.

FINDINGS

A total of 556 respondents were born in Mexico (272 men, 284 women) and 250 in Central America (135 men, 115 women). The majority entered the United States as young adults, with median age at immigration ranging from 20 (Mexican-born men) to 24 (Central American-born women). Nearly 95% of respondents were married or cohabiting. Median age for sexual debut was 18 for women and was younger for men (adjusted mean difference: -2.1 years, 95% CI: -2.6 to -1.7). Median number of lifetime sexual partners was 1 for women and greater for men (adjusted mean difference: 2.0 partners, 95% CI: 1.3-2.7). Contraception use was less likely among men and among Central American women compared to Mexico-born women. Among sexually active persons not using contraception, the most common reasons for nonuse were "Don't want to"/"Don't like any" followed by desire to become or being pregnant. Women reported a median of 3 pregnancies; there were no significant differences based on respondents' region of birth.

CONCLUSIONS

This group of Latino immigrants demonstrated behaviors conducive to reproductive health: late sexual debut, few lifetime sexual partners, and high prevalence of marriage. Preventive education campaigns should focus on maintaining healthy behaviors, especially in men. Identifying groups with common provenance and cultural heritage may aid in maximizing acceptability and effectiveness of prevention programs.

Region of birth, sex, and agricultural work of immigrant Latino farm workers: the MICASA study

Agricultural work is hazardous, and immigrant workers perform the majority of production tasks, yet there are few data describing agricultural work and use of protective measures by demographic characteristics. We examined cross-sectionally the influence of region of birth (Mexico vs. Central America) and sex on agricultural work and use of protective measures in the MICASA cohort of immigrant Latino farm workers in Mendota, California. Of 445 participants, 293 (65.8%) were born in Mexico (163 men, 130 women) and 152 (34.2%) were born in Central America (80 men, 72 women). Men worked on average 74.4 more days than women (95% CI 62.0, 86.9) and were more likely to perform tasks requiring high levels of training or strength, such as machine operation, pruning, picking, planting, and irrigation; more likely to work in dusty conditions; and more likely to work directly with pesticides. Women predominated in packing. Respondents from Mexico were more likely to work with tomatoes and less likely to work with melon and lettuce. Central America-born respondents were less likely to engage in planting, irrigation, and pesticide use. Use of task-appropriate personal protective measures on at least a half-time basis was rare, with the exception of persons working with pesticides (a group limited to men) and for facial scarves among Central American women. Further work should focus on identifying barriers to use of preventive measures and programs to further their use. Educational models accounting for cultural factors and driving social norm change, employer engagement, and use of community health workers (promotores) may be helpful in promoting use of preventive measures.

Concentrations of the urinary pyrethroid metabolite 3-phenoxybenzoic acid in farm worker families in the MICASA study

Indoor pesticide exposure is a growing concern, particularly from pyrethroids, a commonly used class of pesticides. Pyrethroid concentrations may be especially high in homes of immigrant farm worker families who often live in close proximity to agricultural fields, and are faced with poor housing conditions, causing higher pest infestation and more pesticide use. We investigate exposure of farm worker families to pyrethroids in a study of mothers and children living in Mendota, CA within the population-based Mexican Immigration to California: Agricultural Safety and Acculturation (MICASA) Study. We present pyrethroid exposure based on an ELISA analysis of urinary metabolite 3-phenoxybenzoic acid (3PBA) levels among 105 women and 103 children. The median urinary 3PBA levels (children=2.56 ug/g creatinine, mothers=1.46 ug/g creatinine) were higher than those reported in population based studies for the United States general population, but similar to or lower than studies with known high levels of pyrethroid exposure. A positive association was evident between poor housing conditions and the urinary metabolite levels, showing that poor housing conditions are a contributing factor to the higher levels of 3PBA seen in the urine of these farm worker families. Further research is warranted to fully investigate sources of exposure.

Factors associated with agricultural work performed by adolescents from an immigrant farm worker population (MICASA study)

While studies have looked at the relationship of adolescent employment with health outcomes and risk behaviors, few have focused on children of hired farm workers. These children face unique challenges affecting their health and work environment. Exploring the frequency and nature of agricultural work characteristics among adolescent children of Hispanic hired farm workers is important for assessing the potential risks they face.

METHODS

MICASA is a population-based study of settled immigrant Hispanic farm working families in Mendota, California. We selected a cross-sectional random sample of adolescents (ages 11 to 18). Interviews assessed work history, place of birth, and acculturation.

RESULTS

38% of participants were female and 62% were male; 55% were born in the U.S., 38% in Mexico, and 7% in El Salvador; and 49% worked for pay during the last year. Among those who worked, farm work was most frequently reported (73.5%). Among those who had done farm work, the mean age at initiation was 14 years, and they worked a mean of 4.3 weeks during the previous year. Hoeing, picking, and packing/sorting were the most common tasks. In models adjusted for age and sex, low-acculturated adolescents were more likely than moderately acculturated to have worked in the past 12 months, to start work younger than age 14 years, and to do farm work.

SIGNIFICANCE

Farm work is common among adolescents in this Hispanic agricultural community and is strongly associated with foreign birth and low acculturation.

Demographic and migration-related risk factors for low-level smoking in a farm working sample of Latinos (the MICASA study)

Cigarette smoking is the most preventable cause of death in the U.S. Research regarding the phenomenon of low-level smoking, defined as smoking one to five cigarettes per day (CPD) on average, is increasing as its high prevalence is better recognized. The Mexican Immigration to California: Agricultural Safety and Acculturation (MICASA) study is a prospective cohort study of Latino hired farm worker families that assesses respiratory health, including patterns and behaviors of cigarette smoking. The purpose of the present analysis was to establish demographic, migration-related, and psychosocial characteristics and risk factors for low-level smoking. Seven percent of participants were current smokers, 61% of them being low-level smokers. Low-level smokers did not smoke as many days during the past month as those who smoke 6+ CPD (p=0.04). Low-level smokers were more likely than never and former smokers combined not to be married and to experience frequent mental distress. Those who smoke 6+ CPD were also more likely than never and former smokers combined to experience frequent mental distress and to be more acculturated. Low-level smokers have characteristics and risk factors that set them apart from other types of smokers. This increased understanding of low-level smokers can enhance public health education and smoking cessation programs targeted at Latinos.

Agricultural work exposures and pulmonary function among hired farm workers in California (the MICASA study)

Despite California's dependence on hired farm labor, scarce research has been conducted on the respiratory health of hired farm workers. Agricultural exposures to inorganic and organic dusts can adversely affect an individual's respiratory health and differ by farm type and job task. The purpose of the present analysis was to examine associations between agricultural work exposures and pulmonary function among 450 California farm workers. Data were collected as part of the Mexican Immigration to California: Agricultural Safety and Acculturation (MICASA) study, a prospective cohort study examining occupational risk factors and health of hired farm worker families in Mendota, California. Time-weighted self-reported average (TWSRA) dust scores were calculated from assessments of past-12-month agricultural work history. Other dust exposure indicator variables included months worked in agriculture in the past 12 months and years worked in agriculture. Multiple linear regression modeled FEV1 (forced expiratory volume in 1 second), FEF(25-75%) (forced midexpiratory flow rate), FVC (forced vital capacity), FEV6, FEV1/FVC, and FEV1/FEV6 separately. Seventy-six percent of participants had worked in agriculture in the past year. In models conducted for crops and tasks separately, high TWSRA dust score was associated with better FEV6. Crop and task models showed associations between greater months worked in agriculture in the past year and better FEV1, FEF(25-75%), and FEV6. Both models also found greater years worked in agriculture to be associated with worse FEV1/FEV6. Results were generally in the opposite direction as expected given past research but not uncommon. Future research should investigate relationships between pulmonary function and agricultural dust exposure over a lifetime and changes in pulmonary function over time.

Pyrethroids in house dust from the homes of farm worker families in the MICASA study

Indoor pesticide exposure is a growing concern, particularly for pyrethroids, a commonly used class of pesticides. Pyrethroid concentrations may be especially high in homes of immigrant farm worker families, who often live in close proximity to agricultural fields and are faced with poor housing conditions, potentially causing high pest infestation and pesticide use. We investigate levels of pyrethroids in the house dust of farm worker family homes in a study of mothers and children living in Mendota, CA, within the population-based Mexican Immigration to California: Agricultural Safety and Acculturation (MICASA) Study. We present pesticide use data and levels of pyrethroid pesticides in indoor dust collected in 2009 as measured by questionnaires and a GC/MS analysis of the pyrethroids cis- and trans-permethrin, cypermethrin, deltamethrin, esfenvalerate and resmethrin in single dust samples collected from 55 households. Cis- and trans-permethrin had the highest detection frequencies at 67%, with median concentrations of 244 and 172ng/g dust, respectively. Cypermethrin was detected in 52% of the homes and had a median concentration of 186ng/g dust. Esfenvalerate, resmethrin and deltamethrin were detected in less than half the samples. We compared the pyrethroid concentrations found in our study to other studies looking at both rural and urban homes and daycares. Lower detection frequencies and/or lower median concentrations of cis- and trans-permethrin and cypermethrin were observed in our study as compared to those studies. However, deltamethrin, esfenvalerate and resmethrin were detected more frequently in the house dust from our study than in the other studies. Because households whose children had higher urinary pyrethroid metabolite levels were more likely to be analyzed in this study, a positive bias in our estimates of household pyrethroid levels may be expected. A positive association was observed with reported outdoor pesticide use and cypermethrin levels found in the indoor dust samples (rs=0.28, p=0.0450). There was also a positive association seen with summed pyrethroid levels in house dust and the results of a pesticide inventory conducted by field staff (rs=0.32, p=0.018), a potentially useful predictor of pesticide exposure in farm worker family homes. Further research is warranted to fully investigate the utility of such a measure.

Adherence to dietary recommendations is associated with acculturation among Latino farm workers

We examined adherence to dietary recommendations on fruit/vegetable and fat intake and identified correlates with acculturation indicators as well as with family, lifestyle, and occupational factors in a farm worker cohort in central California. Interviewer-administered questionnaires for this cross-sectional study were completed from January 2006 to April 2007. Participants were 18- to 55-y-old Latinos living in Mendota in a farm worker household. We assessed fruit/vegetable consumption and fat intake using the Block Fruit/Vegetable/Fiber Screener and the Block Dietary Fat Screener, respectively. Survey data analysis methods for contingency tables and logistic regression were used for assessing associations. The sample included 802 participants, reporting mean fruit and vegetable intake ( ± SD) of 5.0 ± 1.5 daily servings, and 47% reporting < 5 daily servings. Being born in Mexico or Central America and longer United States residency were associated with higher odds of consuming ≥ 5 daily fruit/vegetable servings and more frequent consumption of field products while working was associated with lower adherence to this recommendation. The average daily percent of calories from fat was 35.0 ± 4.1% and 53% of participants consumed > 35% of daily calories from fat. Men born in Mexico, women born in Central America, and participants who worked in fruit or vegetable crops had higher odds of consuming ≤ 35% of calories from fat. Higher acculturation level, United States school attendance, and having a child at home were associated with lower adherence to this recommendation. Acculturation, family, and occupational correlates of diet quality were identified in this underserved, immigrant population. Our findings may assist program targeting and intervention efforts.

Occupational exposure to particulate matter from three agricultural crops in California

Agricultural work is a major contributor to California's and the nation's economy and employs a large number of workers. However, agricultural work can have numerous risks, such as exposure to elevated levels of particulate matter (PM) and other airborne pollutants with potential adverse health effects. To determine the magnitude of occupational exposures, PM levels were assessed for 89 workers from three major crops in California; almonds, melons and tomatoes. Personal samples were collected for PM2.5 and inhalable PM using personal sampling equipment. Geometric mean concentrations from personal exposure for workers in almonds (inhalable PM=4368 μg/m(3), PM2.5=122 μg/m(3), N=5), tomatoes (inhalable PM=1410 μg/m(3), PM2.5=12 μg/m(3), N=33), and melons (inhalable PM=1118 μg/m(3), PM2.5=19 μg/m(3), N=51) showed high PM exposure when working with these three crops. Large exposure differences by crop were more common than by task (i.e. harvesting, packing and weeding) among the three crops studied. This is the largest study of agricultural workers engaged in hand harvesting, a significant employer of farm labor, and relatively high levels of exposure to PM were measured.

Agricultural work and chronic musculoskeletal pain among Latino farm workers: the MICASA study

BACKGROUND

Agriculture poses varied dangers to hired farm workers in the U.S., but little information exists on occupational risks for chronic musculoskeletal pain. We examined common work positions, such as kneeling, carrying heavy loads, and repetitive motion that may increase the risk for chronic musculoskeletal pain.

METHODS

MICASA is a population-based study of occupational exposures and health in hired farm workers in California. This analysis includes 759 participants, 18-55 years old, engaged in farm work and residing in Mendota, CA. Chronic pain was defined as pain lasting 6 weeks or longer at specific body sites (back, knee, hip, etc.) over the entire farm work career.

RESULTS

Mean age was 37.9 years. Sixty-five percent participants were born in Mexico, 27.7% were born in El Salvador, and 4.2% were U.S-born. Chronic pain was associated with older age and female sex. After adjustment for age, years working in agriculture, and smoking, stooping/bending >30 hr/week among both men (OR = 2.49, 95% CI: 1.03-5.99) and women (OR = 2.15, 95% CI: 1.04-4.46) was associated with chronic hip pain. Driving tractors or other heavy farm equipment >60 hr/week was associated with increased odds of chronic hip pain (OR = 2.16, 95% CI: 1.02-4.54) among men. We also observed significant associations with kneeling or crawling >35 hr/week among women for both chronic back pain (OR = 2.96, 95% CI: 1.27-6.93) and knee pain (OR = 3.02, 95% CI: 1.07-8.50), respectively.

CONCLUSIONS

Chronic musculoskeletal pain is prevalent among farm workers and is associated with common work positions. Further research should focus on developing preventive interventions for tasks associated with increased pain risk. These interventions should be targeted to specific types of agricultural tasks.

Agricultural injury in California Hispanic farm workers: MICASA follow-up survey

The authors report here results from the first follow-up survey of the Mexican Immigration to California: Agricultural Safety and Acculturation (MICASA) cohort of community-dwelling immigrant Hispanic farm workers in California's Central Valley. Among 560 participants the authors observed cumulative 1-year injury incidence of 6.6% (all injuries) and 4.3% (agricultural injuries). Increased prospective injury risk was associated with males, US birth, years lived in the United States, family income, and poor self-rated health. Agricultural injuries were associated most frequently with being struck by an object, falls, and cutting instruments, whereas over two thirds of nonagricultural injuries involved motor vehicles. Prevention should focus on safe handling of tools and materials, falls, and motor vehicle safety.

Acute pulmonary function change associated with work on large dairies in California

OBJECTIVE

To study whether dairy workers in California have lower baseline and greater cross-shift decrements in lung function than control employees.

METHODS

A cross-sectional study of 210 dairy and 47 control workers who completed questionnaires and spirometry before and after the work shift.

RESULTS

Dairy work was associated with mean baseline differences of -0.132 L (P = 0.07) and -0.131 L (P = 0.13) in forced expiratory volume in 1 second and forced vital capacity, respectively, compared with control employees, adjusting for age, height, smoking status, and days back at work since last day off. Dairy work was associated with a mean cross-shift difference of -65.2 mL (P = 0.02) and -103.1 mL (P < 0.01) in forced expiratory volume in 1 second and forced vital capacity, respectively, adjusting for smoking status and work-shift time.

CONCLUSIONS

Dairy work in California was associated with mild acute airway obstruction. The unclear long-term effect of dairy work in California merits further investigation.

A survey of particulate matter on california dairy farms

Over the past 30 yr, individual California dairy operations have grown in size; however, little is known about the distribution and determinants of particulate matter (PM) concentrations on these dairies. Elevated exposure to PM is associated with respiratory and cardiovascular health effects, particularly in occupational settings. The purpose of this study was to quantify the concentrations of PM and all inhalable PM (0-100 µm) on California dairies. Samplers were placed at various locations (e.g., milking parlor, grain storage area, drylot corral, and freestall barns) on 13 different dairies to collect PM and all inhalable PM during the 2008 summer months. The PM and all inhalable PM concentrations varied between different areas on a dairy and from dairy to dairy. Geometric mean concentrations for PM and inhalable PM were 24 µg m (range, 2-116 µg m) and 332 μg m (range, 74-1690 µg m). A key variable for explaining variation in PM concentrations with a mixed effects model was regional background ambient concentrations of PM No significant differences were observed in mean concentrations between upwind and downwind fence line concentrations (adjusted geometric mean ratio [AGMR] = 0.7; 95% CI, 0.4-1.3), although significant differences were found between upwind and central location mean values (AGMR = 0.5; 95% CI, 0.3-0.8; < 0.01). These results indicate dairy PM sources and, thus, elevated occupational exposure. Covariates, such as the age of the dairy and number of cows in the freestall barn and drylot corral, were important variables in explaining PM concentration variability. Levels of PM were lower compared with dairies in other U.S. states and other countries.

Cumulative trauma disorders among California veterinarians

BACKGROUND

The prevalence of cumulative trauma disorders (CTDs) in veterinarians has not been adequately studied.

METHODS

A questionnaire was sent to 2,000 California veterinarians in 1997; the return rate was 73% (n = 1,415).

RESULTS

Ninety-six percent (1,353) of the respondents were professionally active and were included in the analyses. Sixty-four percent were male and 90% were working full-time. One-fourth of the respondents reported a CTD during their career that required treatment or restricted usual activities. Two-thirds of those reporting CTDs reported chronic or residual problems. In a multivariate regression analysis female sex, working full-time, rectal palpations, and large animal practice were significant risk factors for CTDs.

CONCLUSIONS

Being in large animal practice increased the CTD risk for both women and men whether they worked full or part-time. CTD risk was highest in women working full-time and doing 80% rectal palpations. Preventive methods to attenuate the risk of CTDs especially in large animal practice should be investigated.

Activation of inflammatory responses in human U937 macrophages by particulate matter collected from dairy farms: an in vitro expression analysis of pro-inflammatory markers

BACKGROUND

The purpose of the present study was to investigate activation of inflammatory markers in human macrophages derived from the U937 cell line after exposure to particulate matter (PM) collected on dairy farms in California and to identify the most potent components of the PM.

METHODS

PM from different dairies were collected and tested to induce an inflammatory response determined by the expression of various pro-inflammatory genes, such as Interleukin (IL)-8, in U937 derived macrophages. Gel shift and luciferase reporter assays were performed to examine the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and Toll-like-receptor 4 (TLR4).

RESULTS

Macrophage exposure to PM derived from dairy farms significantly activated expression of pro-inflammatory genes, including IL-8, cyclooxygenase 2 and Tumor necrosis factor-alpha, which are hallmarks of inflammation. Acute phase proteins, such as serum amyloid A and IL-6, were also significantly upregulated in macrophages treated with PM from dairies. Coarse PM fractions demonstrated more pro-inflammatory activity on an equal-dose basis than fine PM. Urban PM collected from the same region as the dairy farms was associated with a lower concentration of endotoxin and produced significantly less IL-8 expression compared to PM collected on the dairy farms.

CONCLUSION

The present study provides evidence that the endotoxin components of the particles collected on dairies play a major role in mediating an inflammatory response through activation of TLR4 and NF-κB signaling.

A pilot binational study of health behaviors and immigration

In the US, Mexican immigrant women often have better health outcomes than non-Hispanic white women despite a greater health risk profile. This cross-sectional pilot study compared women living in Chavinda, Michoacán (n = 102) to women who had migrated from Mexico to Madera, California (n = 93). The interview gathered information on acculturation and risk behaviors including smoking, alcohol use and number of sexual partners. The results suggest that more acculturated women living in the US are more likely to consume alcohol. US residence and higher acculturation level was marginally associated with having more than one sexual partner. There were no differences between odds of smoking among Chavinda and Madera women. While results with acculturation are not consistently significant due to small sample sizes, the results are suggestive that acculturation among immigrant Hispanic women in the US may be associated with adverse health behaviors, and selective migration seems less likely to account for these differences.

Characterization of endotoxin collected on California dairies using personal and area-based sampling methods

Endotoxin, found in the cell wall of gram negative bacteria, is an important contributor to the biological activity of agriculture particulate matter (PM). We analyzed endotoxin in PM collected on 13 California dairies and from the breathing zone of 226 workers during the summer months of 2008. Two particle size fractions were measured: PM(2.5) and inhalable PM. Recombinant factor C assays were used to analyze biologically active endotoxin, while gas chromatography coupled with mass spectrometry in tandem was used to quantify total lipopolysaccharide. Biologically active endotoxin concentrations in the inhalable PM size fraction from area-based samples ranged from 11-2095 EU/m(3) and from 45-2061 EU/m(3) for personal samples. Total endotoxin in the inhalable PM size fraction ranged from 75-10,166 pmol/m(3) for area-based samples and 34-11,689 pmol/m(3) for personal samples. Area-based geometric mean concentrations for biologically active endotoxin and total endotoxin in PM(2.5) and inhalable PM size fractions were 3 EU/m(3), 149 EU/m(3), 60 pmol/m(3), and 515 pmol/m(3), respectively. Personal geometric mean concentrations in the inhalable PM size fraction were 334 EU/m(3), and 1178 pmol/m(3). Biologically active and total endotoxin concentration variation was best explained by meteorological data, wind speed, relative humidity, and dairy waste management practices. Differences in endotoxin concentration and composition were found across locations on the dairy.

A global perspective of migration and occupational health

BACKGROUND

Global migration has dramatically increased over the past decade and is at an all-time high, approaching 200 million persons per year. Demographics and economic interdependence suggest that immigration will continue for the near future at record high levels.

METHODS

A review of the few studies that have investigated occupational injury and illness rates among immigrant populations.

RESULTS

Existing data indicate that higher rates of fatal and non-fatal injuries are common compared to native populations. This increase is in part due to immigrants working in higher risk occupations (e.g., agriculture, construction), but occupational morbidity and mortality is higher among immigrants than native-born workers within occupational categories.

CONCLUSIONS

Research is needed to identify the causes of increased risk among immigrants and to provide direction to effective public health interventions. Research methods must be adapted to different epidemiologic characteristics of immigrant populations, including lack of standard sampling frames, different language and culture from the dominant culture, and precarious work status.

Aerosols in the agricultural setting

This report summarizes discussions chaired by Kent Pinkerton held during the New Paths: Health and Safety in Western Agriculture conference, November 11-13, 2008. Research on air quality and aerosols in the agricultural setting was presented and discussed, providing insight into critical issues by many of the prominent scientists in this field. The panel discussion provided an overview of recent advances and future directions for research regarding sampling and exposure assessment of biologically active aerosols. This analysis considers chemical composition, individual exposures, and subsequent health effects experienced in large- and small-scale farming operations. The breakout discussion focused on other sources of particulate matter associated with agricultural activities prominent in various regions of the western United States. The complementary directions for these discussions fully demonstrate the wide range of concerns and issues that exist regarding bioaerosols and ambient dust associated with agricultural activities.

Pneumoconiosis from agricultural dust exposure among young California farmworkers

BACKGROUND

Agricultural workers are exposed to airborne pollutants, including organic and inorganic (mineral) dusts.

OBJECTIVES

Lung autopsy specimens from consecutive coroner's cases of Hispanic males in Fresno County, California, (n = 112) were obtained to determine whether mineral dust exposure in agricultural work leads to pneumoconiosis.

METHODS

The left lung was fixed by inflation. We evaluated airway and parenchymal pathology using standardized diagnostic criteria and semiquantitative grading schemata, including the grading of small airways for fibrosis and birefringent mineral dust particles. We analyzed lung dust burden on a subset of 37 lungs following bleach digestion, using scanning electron microscopy (SEM), X-ray spectrometry (XRS) and image analysis, and by X-ray diffraction for crystalline silica (CSi). Farmworkers comprised 51.5% and nonfarmworkers 48.5% of the samples.

RESULTS

Proximal airways demonstrated little mineral dust accumulation, but membranous and respiratory bronchioles had wall thickening, remodeling, and inflammation associated with carbonaceous and mineral dust deposition. These changes were independently associated with agricultural work, cigarette smoking, and increased age. Mineral dust small airways disease, pneumoconiosis (macules and nodules), and pathologic changes consistent with chronic bronchitis, emphysema, and interstitial fibrosis predominated in farmworkers compared with nonfarmworkers. CSi, determined gravimetrically, and aluminum silicate particles, determined by SEM/XRS, were increased in the lungs of farmworkers compared with nonfarmworkers and were significantly (p < 0.05) associated with small airway disease and pneumoconiosis.

CONCLUSION

Mineral dust exposure is associated with increased small airway disease and pneumoconiosis among California farmworkers; however, the clinical significance and natural history of these changes remains to be determined.

Recruiting strategy and 24-hour biomonitoring of paraquat in agricultural workers

The objectives of this study were to recruit agricultural workers in Costa Rica to participate in a 24-hour urine collection for paraquat exposure assessment and to compare the 24-hour sampling to end-of-shift sampling. The authors recruited 187 handlers and 54 nonhandlers from coffee, banana, and palm oil plantations. The completeness of 24-hour urine samples collected (a total of 393 samples) was confirmed by questionnaire and urinary creatinine level. For a subset of 12 samples, the absorbed paraquat level was determined in 24-hours and end-of-shift spot urine samples. The participation rate for handlers was approximately 90%. The completeness of 24-hour urine collections was verified as the overall average of creatinine levels from 393 urines (1.11+/-0.50 g/L). A total of 92.4% to 96.7% of urine samples were considered within the acceptable range of urinary creatinine, whereas 94.7% of the samples were described as "complete" from the questionnaire. Measured creatinine correlated well to predicted values (r=.327, p=.0024, 95% CI .12-.51). Detected paraquat levels in spot urine samples had a sensitivity of 96.9% at the high specificity of 100% compared to 24-hour urine samples as the gold standard. There was a significant (p<.0001) correlation between spot and 24-hour urine paraquat levels (r=.7825, 95% CI .61-.88). The recruiting strategy was successful in getting 24-hour urine samples from a farm worker population. Comparison between the paraquat levels in spot and 24-hour urine samples demonstrated that for this compound, end-of-shift spot urine samples would be an appropriate substitute for 24-hour collections.

Occupational paraquat exposure of agricultural workers in large Costa Rican farms

OBJECTIVE

Paraquat is an herbicide widely used worldwide. This study determined the extent of occupational exposure to paraquat among farm workers in Costa Rica and identified determinants of occupational exposure.

METHODS

Twenty-four hour urine samples were collected from 119 paraquat handlers and 54 non-handlers from banana, coffee and palm oil farms. Information about herbicide handling operations was also collected. The urinary paraquat levels were determined by an enzyme-linked immunosorbent assay (ELISA) with a limit of quantification (LOQ) of 2 ng/mL. Inhalable dust and airborne paraquat levels were simultaneously measured for a subset of the participants.

RESULTS

Urinary paraquat measurements were non-detectable or very low when workers did not handle paraquat. For handlers, 83.3, 47.1 and 63.9% of the samples were below the LOQ on before-, during- and after-paraquat spray days, respectively. The arithmetic mean (+/-SD) of urinary paraquat level on days when workers handled paraquat was 6.3 (+/-10.45) microg/24 h. Paraquat exposures among handlers on spray day were significantly associated with the type of crop.

CONCLUSION

Non-handlers had negligible urinary paraquat, while detectable paraquat exposures were observed among handlers on spray day. Urinary paraquat levels were different by crop.