Low level of exposure to pesticides leads to lung dysfunction in occupationally exposed subjects.
Hernández AF, Casado I, Pena G, Gil F, Villanueva E, Pla A.

Department of Legal Medicine and Toxicology, University of Granada Medical School, Granada, Spain. ajerez@ugr.es

Pesticides may contribute to adverse respiratory health effects among farmers and have been considered one causal factor for the rise in asthma prevalence. This cross-sectional study was conducted to evaluate potential respiratory function abnormalities following long-term pesticide exposure by means of a complete pulmonary function testing, including spirometry, lung volumes, and diffusing capacity for carbon monoxide. The study population was comprised by workers from a prominent intensive agriculture area of southern Spain that relied on pesticides for the control of plagues. Eighty-nine pesticide sprayers of plastic greenhouse farming and a control group of 25 nonspraying control farmers from the same area were interviewed by a general practitioner asking about sociodemographic factors, occupational exposure, and clinical symptoms by using a structured questionnaire. Multiple regression analyses showed a relationship of short-term exposure to pesticides (as indicated by a drop in serum cholinesterase > 25% of baseline levels) with reduced forced expired volume in 1 s, and of long-term exposure (as indicated by a cumulative pesticide exposure index) with reduced forced expiratory flow rate. Exposure to bipyridilium-class herbicides was a determinant of a fall in the diffusing capacity of the lungs, and neonicotinoid insecticides showed a relationship with lower pulmonary volumes (total lung capacity, residual volume, and functional residual capacity), suggestive of restrictive lung disease, and with an increased risk of reporting irritative symptoms.

PMID: 18645724 [PubMed - indexed for MEDLINE] Inhal Toxicol. 2008 Jul;20(9):839-49. Links

Lu C, Barr DB, Pearson MA, Walker LA, Bravo R.

aDepartment of Environmental and Occupational Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.

J Expo Sci Environ Epidemiol. 2008 Sep 3.

Despite the widespread use of synthetic pyrethroid insecticides that led to common exposure in the population, very few studies have been conducted to quantitatively assess human, particularly, children’s, long-term exposures to pyrethroid insecticides.

The objective of the Children Pesticide Exposure Study – Washington (CPES-WA) was to establish the longitudinal exposure profiles for pyrethroid insecticides in a cohort of children living in an urban
and suburban community using urinary pyrethroid metabolites as exposure biomarkers.

The results from this analysis will allow us to examine potential risk factors in relation to the elevated pyrethroid insecticide exposure in children. A total of 23 children, aged 3-11 years, who only consumed conventional diets were enrolled in this 1-year study. We provided organic food items to children for 5 consecutive days in the summer and fall sampling seasons. We measured urinary metabolites for the synthetic pyrethroid insecticides in urine samples that were collected twice daily during each of the four sampling seasons. 3-phenoxybenzoic acid was frequently detected in the urine samples with mean and median daily volume-weighted average levels of 1.5 and 1.2 mug/l, followed by trans-2,2-(dichloro)-2-dimethylvinylcyclopropane carboxylic acid (1.4 and 1.0 mug/l) and cis-2,2-(dichloro)-2-dimethylvinylcyclopropane carboxylic acid (0.5 mug/l, and non-detected). When we took into account season, age, sex, diet, and self-reported residential use of pyrethroid insecticides in a linear mixed-effects model, the results suggested that the combination of the use of pyrethroid insecticides in the household, dietary intake, and seasonal differences play a significant role in predicting children’s exposure to synthetic pyrethroid insecticides. We found CPES-WA children were continuously exposed to pyrethroid insecticides through their diets all year long, and this chronic exposure pattern was periodically modified by episodes of relatively high exposures from residential uses.

Future research should be devoted to enhancing our understanding of the complexity of pyrethroid insecticide exposure patterns.Journal of Exposure Science and Environmental Epidemiology advance online publication, 3 September 2008; doi:10.1038/jes.2008.49.

http://www.ncbi.nlm.nih.gov/pubmed/18766203?dopt=AbstractPlus

PMID: 18766203 [PubMed - as supplied by publisher]

Toxic levels falling in the Arctic
The Canadian Press reports the first large-scale attempt in a decade to measure contaminants in Arctic food animals has found carcinogens such as PCBs and other pesticide toxins “have largely leveled off or have begun declining.” Survey researcher Laurie Chan of the University of Northern British Columbia says it’s good news that “organochlorines, like DDT or chlordane or toxaphene or industrial chemicals like PCB, are declining.” Chan called the falling levels proof that “the Stockholm Convention is having some effect.” The 2004 convention limited the use of the so-called “dirty dozen” chemicals that are pushed north into the Arctic by global air currents. Canada’s Inuit once had some of the highest PCB levels — up to 10 times the levels found in southern Canada — and PCB was found in the breast milk of Inuit mothers. A 2003 study found statistically significant nervous system and behavioral changes in Inuit babies that may be linked to PCBs. Since 1997, PCB levels in whales, walruses and ringed seals have fallen by an average of 43 percent while the PCB contamination reaching local people has dropped by an average of 20 percent. Exposure to toxaphene — an insecticide that damages the lungs, nervous system and kidneys — has dropped an average of one-third across the Arctic. Unfortunately, the study found that levels of mercury, probably from the world’s growing number of coal-fired powerplants, is rising in some animals. Meanwhile, levels of some persistent organic pollutants (POPs) like the pesticide endosulfan remain high in the Arctic, underscoring the need for global action to ban POPs pesticides.