| 1. |
- Crowe, Jennifer, 1976-
(författare)
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Heat exposure and health outcomes in Costa Rican sugarcane harvesters
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background The remarkably efficient mechanisms of the human body to maintain its core temperature of 37°C can be inadequate when harsh climatic conditions and excessive muscle movement lead to heat stress, dehydration and potential heat illness, ranging from minor symptoms such as fatigue to a potentially fatal heat stroke. Agricultural workers in the tropics are at high risk, which is expected to increase with climate change. Sugarcane harvesting in Costa Rica is largely done by cutting the cane with a machete, by temporary, sub-contracted workers who are often migrants and living in poverty. Sugarcane harvesters are known to be affected by an epidemic of chronic kidney disease of non-traditional origin, currently hypothesized to be related to working conditions.Objectives This work aimed to better understand and document sugarcane harvester exposure to heat and the health consequences of working under such conditions. Specific objectives were to 1) Document working conditions and heat in the Costa Rican sugarcane industry (Paper I); 2) Quantify heat stress exposures faced by sugarcane harvesters in Costa Rica (Paper II); and 3) Quantify the occurrence of heat stress symptoms and abnormal urinary parameters in sugarcane workers in Costa Rica (Papers III and IV).Methods This study took place over three harvests following a pilot assessment prior to the first harvest. Methods included direct observation, semi-structured interviews with 24 individuals and a participatory workshop with 8 harvesters about heat-related perceptions, exposures and coping strategies during the harvest and non-harvest season (Pilot). Researchers accompanied workers in the field during all three harvests, measured wet bulb globe temperature (WBGT) and conducted direct observation. Heat exposure assessment was conducted by calculating metabolic load, WBGT and corresponding limit values based on international guidelines (NTP and OSHA) (Harvest 1). Self-reported symptom data were collected using orally-administered questionnaires from 106 sugarcane harvesters and 63 non-harvesters from the same company (Harvest 2). Chi-square test and gamma statistic were used to evaluate differences in self-reported symptoms and trends over heat exposure categories. Finally, liquid consumption during the work shift was documented and urinalysis was conducted pre-and post-shift in 48 sugarcane harvesters on three days; differences were assessed with McNemar´s test on paired proportions (Harvest 3).Results Sugarcane workers in both the harvest and non-harvest seasons are exposed to heat, but particularly during the harvest season. Field workers have to carry their own water to the field and often have no access to shade. Some plantworkers are also exposed to intense heat. The metabolic load of sugarcane harvesting was determined to be 261 W/m2. The corresponding threshold value is 26 ◦C WBGT, above which workers should decrease work load or take breaks to avoid the risk of heat stress. Harvesters in this study were at risk of heat stress as early as 7:15 am on some mornings and by 9:00 am on all mornings. After 9:15 am, OSHA recommendations would require that harvesters only work at full effort 25% of each hour to avoid heat stress. Heat and dehydration symptoms at least once per week were experienced significantly more frequently among harvesters than non-harvesters (p<0.05): headache, tachycardia, fever, nausea, difficulty breathing, dizziness, and dysuria. Percentages of workers reporting heat and dehydration-related symptoms increased over increasing heat exposure categories. Total liquid consumed ranged from 1 to 9 L and differed over days (median 5.0, 4.0 and 3.25 on days 1, 2 and 3 respectively). On these same days, the two principle indicators of dehydration: high USG (≥1.025) and low pH (≤5), changed significantly from pre to post-shift (p=0.000 and p=0.012).Proportions of workers with proteinuria >30 mg/dL, and blood, leucocytes and casts in urine were also significantly different between pre and post-shift samples at the group level, but unlike USG and pH, these alterations were more frequent in the pre-shift sample. 85% of workers presented with proteinuria at least once and 52% had at least one post-shift USG indicative of dehydration.Conclusion Heat exposure is an important occupational health risk for sugarcane workers according to international standards. A large percentage of harvesters experience symptoms consistent with heat exhaustion throughout the harvest season. Pre and post-shift urine samples demonstrate dehydration and other abnormal findings. The results of this study demonstrate an urgent need to improve working conditions for sugarcane harvesters both under current conditions and in adaptation plans for future climate change.
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| 2. |
- Rodríguez, Teresa, 1966-
(författare)
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Environmental Pesticide Exposure and Neurobehavioral Effects among Children of Nicaraguan Agricultural Workers
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Children exposed to pesticides are susceptible for neurodevelopmental disruption. Data from developing countries are scarce.Aim: Assessing long-term and recent pesticide exposure in Nicaraguan children in relation to parental pesticide use and examining potential associated neurobehavioral effects.Methods: In the first study, pre- and post-spraying urinary residues of the chlorpyrifos metabolite TCPY and diazinon metabolite IMPY were measured among 7 subsistence farmers and 10 plantation workers, and in one child per worker. In the second study, for 110 children in an agricultural village and 22 in a non-agricultural village, aged 7-9, parental pesticide use was assessed by hours of spraying and kilograms of active ingredients during pre-and-postnatal time windows, as proxies for children’s long term pesticide exposures. Urinary TCPY, 3-PBA (pyrethroid metabolite), and 2,4-D were determined in 211 samples of 74 children of the agricultural village. IQ components and total IQ (WISC-IV) were evaluated in all agricultural village children. Behavior was evaluated with the Conners’ Teacher Rating Scale-Revised: Short. Multivariate linear regression models assessed associations between long-term and recent exposure to organophosphates and pyrethroids and cognitive and behavioral scales.Results: In study 1, post-spraying urinary levels of pesticide metabolites of subsistence farmers and their children were highly correlated (r=0.85), but not those of plantation workers and their children. In study 2, a wide range of exposures was reported by parents for all pesticides and time windows. The median urinary TCPY (3.7 μg/g creatinine), 3-PBA (2.8), and 2,4-D (0.9) were comparable to other studies for TCPY and 3-PBA but high for 2,4-D. Maximum levels were the highest reported for all compounds. Prenatal use of organophosphates affected working memory, and methamidophos also verbal comprehension and total IQ. Urinary TCPY was associated with poorer working memory. Organophosphate exposures were not associated with children’s behavior. Pyrethroid exposure during the first year of life associated with poorer perceptual reasoning and behavior, and urinary 3-PBA with a number of cognitive functions and ADHD in girls but not in boys.Conclusion: Nicaraguan children in poor agricultural areas are highly exposed to pesticides, which is influenced by parental pesticide use in subsistence farms. Organophosphate and pyrethroid exposures adversely affect their neurobehavioral development.
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| 3. |
- Wesseling, Catharina
(författare)
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Health effects from pesticide use in Costa Rica : an epidemiologic approach
- 1997
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The use of toxic pesticides is increasing in developing countries, often under unsafe conditions. Poisonings are a well-known but underreported public health problem, and studies on long-term effects are sparse. Therefore, a survey was carried out to determine the incidence and the risk factors for pesticide poisonings in Costa Rica, integrating data from national registries of occupational accidents, hospitalizations, and fatalities between 1980-1986. A case series further assessed the exposures that can lead to a fatal outcome in nonintentional paraquat poisonings. A cross-sectional study among 211 banana plantation workers tested the hypothesis that chronic neurobehavioral deficits occur as a consequence of previous intoxication with cholinesterase inhibiting pesticides. An ecologic study tested the hypothesis that geographical differences in cancer incidence are associated with pesticide use. A cohort of 34,457 banana plantation workers with more than 400,000 person years was established to assess the cancer pattern among workers with a high level of exposure to pesticides (in particular dibromochloropropane), and to examine the feasibility of computerized record linkage between various registries in Costa Rica. In addition, health hazards from pesticide use in the Third World were reviewed, and some possibilities and limitations for epidemiologic research in developing countries were assessed. Cholinesterase inhibitors and paraquat caused the vast majority of the poisonings. Young workers, female workers and banana plantation workers were the groups at highest risk for occupational poisonings. Suicide as a cause of severe poisonings was less frequent than expected. It was estimated that, yearly, 1.5% of the agricultural workers suffer a work-related pesticide poisoning requiring medical attention. The case series suggested that paraquat may be fatal by dermal absorption of diluted paraquat, by ingestion of very low doses, and possibly by inhalation of diluted spray. Mild neurobehavioral deficits were found among previously poisoned workers, both by organophosphates and carbamates; after a poisoning, the workers seemed to become more susceptible to subsequent low dose exposures to cholinesterase inhibitors. Pesticide use was associated with increased cancer incidence in the most rural areas of Costa Rica, including lung and female hormone related cancers. Male banana plantation workers were at increased risk of melanoma and penile cancer, and female workers of cervical cancer and leukemia. Pesticides appear to be a public health problem throughout the Third World. Epidemiologic research to assess these problems is difficult because of methodological and infrastructure restrictions. However, high exposures provide good opportunities to carry out etiologic research; another advantage is that participation rates are often very high. Registry based studies may be feasible, but sometimes after costly improvements of the registries. This thesis indicates that pesticide exposure in Costa Rica is associated with an increased risk of various health effects.
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