Exposure to pesticides and metal contaminants of fertilizer among tree planters

Gorman Ng M, Stjernberg E, Koehoorn M, Demers PA, Davies HW. Exposure to pesticides and metal contaminants of fertilizer among tree planters. Annals of Occupational Hygiene 2011; 55(7):752-763.

In British Columbia, Canada, harvested forests are manually replanted by seasonal workers. The work is known to be physically demanding and ergonomically difficult, and recently, there have been concerns over chemical exposures due to pesticide residues on seedlings, fertilizers (often applied alongside seedlings), and potential metal contamination of these fertilizers. This study aimed to characterize metal and pesticide exposure among a sample of British Columbia tree planters. Between May 2006 and April 2007, exposure measurements were taken from 54 tree planters at five geographically disperse worksites throughout British Columbia. Four worksites were using fertilizer and one was not. Metal concentrations were measured by inductively coupled plasma mass spectrometry on post-shift hand wipes, full-shift personal air sample, bulk soil, seedling root balls, and fertilizer samples. Pesticides were measured on post-shift hand wipes and on bulk seedling samples. Seedling nursery pesticide application records were used to focus pesticide analyses on pesticides known to have been applied to the seedlings used at the study sites. Carbamate pesticides were analyzed by high-performance liquid chromatography/mass spectroscopy and all other pesticides by gas chromatography mass spectrometry. No evidence was found that tree planters who worked with fertilizer were at an elevated risk of exposure to arsenic, lead, cadmium, chromium, and nickel relative to tree planters who did not. Pesticide residues were found on seedlings taken from work sites early in the tree planting season in April 2007. At these worksites, the fungicides chlorothalonil and iprodione were found on the skin of workers at low levels (range 0.37-106.3 ng cm(-2) and 0.48-15.9 ng cm(-2), respectively), providing evidence for exposure potential. Very poor hygiene conditions were observed at all tree planting work sites. Hand washing facilities were not available at work sites and only 5.6% of subjects reported hand washing during the work day, including prior to eating or smoking. Gloves were worn by all subjects but no personal protective equipment programs existed to train workers in the correct use or selection of gloves, and consequentially, many glove choices were inappropriate. The lack of hand washing facilities combined with incorrect glove use could increase the duration of dermal exposure and increase the risk of hand-to-mouth ingestion exposure.

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