Pesticide safety training and access to field sanitation among migrant farmworker mothers from Starr County, Texas

Very little published research describes employer compliance with EPA-mandated Worker Protection Standard (WPS) pesticide safety training and the OSHA Field Sanitation Standard among farmworker women in general and mothers specifically. A goal of both standards is limiting farmworkers' exposure to potentially hazardous agricultural pesticides. Data from a NIOSH-supported cohort study ("Injury and Illness Surveillance in Migrant Farmworker Families") allowed for examining these issues. The cohort included 267 migrant farmworker families who usually reside along the Texas-Mexico border (Starr County, Texas). Data were collected in Starr County during in-home interviews. Of 102 mothers who participated in migrant farm work during summer 2001, 57 (55.9%) reported having ever received training/instruction in the safe use of pesticides, while 47 (46.1%) reported having received training within the previous five years, as required by WPS. Of trained mothers, 91.5% to 93.6% reported that their training covered key WPS areas: (1) entry into a recently treated field, (2) pesticide related injuries/illnesses, and (3) where to go and who to contact for emergency care following exposure. Regarding access to field sanitation, 67.5% to 84.2% of 77 mothers who worked outside Texas reported employer-provided decontamination supplies (e.g., soap, wash water, towels, and toilet facilities). However, a strikingly smaller proportion (12% to 28%) of 25 mothers who worked within Texas reported access to the same resources, suggesting discrepancies in compliance across the U.S. Due to the low level of employer compliance with both WPS and OSHA mandated standards, increased enforcement and an alternate delivery of pesticide training is recommended.     

Chromate Generation by Chromate Depleted Subsurface Materials

Soluble chromate concentrations as high as 200 μg Cr L^-1 have been reported in water samples from monitoringwells tapping alluvial deposits allegedly contaminated bylaboratory waste as well as control wells off site andupgradient (shallow aquifer) near Davis California, U.S.A. In this report we present evidence that these Cr(VI) levelscould have been generated by geogenic processes rather thanby anthropogenic inputs. We tested the hypothesis thatnative Cr(III) has been and can be oxidized to chromate bynative manganese oxides. Twenty-three drill core samples(all unsaturated) were retrieved from depths varying from1.5 to 22.5 m in 6 different wells. Visible nodules ofMnO₂ were dispersed throughout many of the samples andcarbonates were also present. Sample pH values averagedabout 8.0 and organic C was mostly less than 1.0 g kg^-1. Total Mn and Cr averaged 835 and 191 mg kg^-1respectively. All samples had the capability to oxidizeadded Cr(III) to Cr(VI). To determine the inherent capabilityof the samples to produce Cr(VI) from native Cr(III), subsamples were extracted with 5 mM CaSO₄ plus 5 mM MgSO₄ until Cr(VI) was no longer detected. After freeze-drying, deionized-distilled water was added to theleached samples to approximately field capacity (0.03 MPa). Freeze drying did not generate Cr(VI). These samples wereincubated in polyethylene film bags at room temperature inthe dark. After 1 week incubation, water in the samples wasextracted by centrifugation and the extracts were analyzedfor Cr(VI). All of the samples generated Cr(VI), and theconcentrations in the extracts ranged from 20 to 100 μg Cr L^-1. Total chromium, endemic chromium VI and chromium VI generated in leached samples were not statistically different between samples from onsite and control samples taken offsite and upgradient in respect to the shallowest aquifer.