Pesticides-l Digest, Vol 150, Issue 8

Title: The Perplexing Paradox of Paraquat: The Case for Host-Based Susceptibility and Postulated Neurodegenerative Effects
Authors: B.C. Jones, X. Huang, R.B. Mailman, L. Lu and R.W. Williams
Source: Journal of Biochemical and Molecular Toxicology, published online, 2014
http://onlinelibrary.wiley.com/doi/10.1002/jbt.21552/full

Paraquat is an herbicide used extensively in agriculture and has also been proposed to be a risk factor for Parkinson's disease. To date, experimental, clinical, and epidemiological data on paraquat neurotoxicity have been equivocal. In this short review, we discuss some technical and biological mechanisms that contribute to inconsistencies regarding paraquat neurotoxicity. We hypothesize that individual genetic variations in susceptibility generate major differences in neurotoxic risk and functional outcome. Identifying these heritable sources of variation in host susceptibility, and their role in complex gene–environment interactions, is crucial to identify risk biomarkers and to devise better prevention and treatment for those exposed to paraquat and other potential neurotoxicants.

Title: Wash. pesticide worker removal up in 2013
Date: 11 March 2014
Source: Capital Press
http://www.capitalpress.com/article/20140311/ARTICLE/140319953

Overexposure to pesticides caused nine orders for temporary work removal of pesticide applicators in Washington in 2013, according to the state Department of Labor & Industries.

That’s the most since 18 were temporarily removed in 2007. There were five in 2012, none in 2011 and 2010, seven in 2009 and one in 2008. There were seven in 2006, 10 in 2005 and a record 22 in 2004, the first year of monitoring.

Those temporarily removed in 2013 were all applicators employed by six separate tree fruit growers in Central Washington, says an L&I report. All nine handled toxic organophosphate and n-methyl carbamate pesticides, including Lorsban 4E, Guthion and Sevin 4F.

Guthion, used to control codling moth in apples and pears and also used in cherries, was banned by the EPA in September 2012. However, growers were allowed to use up existing supplies through September 2013.

The 2014 results should be interesting with Guthion gone, said Richard Fenske, director of the Pacific Northwest Agricultural Safety and Health Center at the University of Washington in Seattle.

Fenske and Kirk Mayer, manager of the Washington Growers Clearing House Association in Wenatchee, were involved in the start of the monitoring program when it was done by the state Department of Health.

The program checks workers for levels of cholinesterase, a blood enzyme needed for nervous system health. A number of compounds, including caffeine, medications and chemicals found in pesticides, can depress cholinesterase levels.

Mayer noted there’s never been a reported pesticide illness by anyone monitored by the program. He said he’s surprised the number of temporary work removals is up this year and that he gives little credence to the 22 in 2004 because there were procedural problems in the first year.

“When we have a (cholinesterase) depression among pesticide workers it’s a fairly high possibility that it’s pesticide related, but there’s also a smaller possibility it could be caused by other things like diet, drugs and alcohol,” Mayer said.

“I’ve considered it to be a success story because the cholinesterase measurement catches depression before it gets too severe. Workplace removal occurs usually before there’s any symptoms,” Fenske said.

L&I work site field evaluations of action-level depressions of cholinesterase identified multiple Pesticide Worker Protection Standard violations that may have contributed to over exposure including training, respiratory protection and personal protective equipment requirements, the report states.

“One concern consistently noted during work site evaluations was often finding employer-provided handler training to be of limited quality,” the report states.

Early on the program revealed potential exposure from baseball caps and sweatshirt hoods that didn’t get cleaned and weren’t fully covered by protective clothing, Mayer said.

“A value in the program has been increased cooperation and communication” among L&I and the departments of Agriculture and Health that has led to them working more closely to address potential causes, he said.

The state Department of Agriculture has a good hands-on pesticide applicator training program designed for Spanish-speaking people, Fenske said. The Clearing House Association and other groups sponsors some of the training, the program could use more funding and be expanded, Mayer said.

Temporary worker removal is triggered by a 30-percent depression in red blood cell cholinesterase or a 40-percent decline in serum cholinesterase while a 20-percent depression requires employer review of pesticide handling practices.

There were four cases in the 20 percent range in 2013. A total of 328 growing operations and 1,994 pesticide handlers participated in baseline cholinesterase testing. Of the 1,994, 226 were tested at least once more during the application season.

Use of certain products triggers voluntary baseline testing and the amount of usage triggers second and third testing, Fenske said.

Depression of cholinesterase in the blood and can lead to nerves being over stimulated to the point of exhaustion, blurred vision, diarrhea, tremors, seizures, loss of consciousness and death, L&I has said.

Farm organizations say pesticides are safe if administered properly, but environmentalists have been working for years to ban some of them as too dangerous.

Title: Determination of Pesticide Residues in Honeybees using Modified QUEChERS Sample Work-Up and Liquid Chromatography-Tandem Mass Spectrometry
Authors: Ż. Bargańska, M. Ślebioda and J. Namieśnik
Source: Molecules, Vol. 19, 2014
http://scholar.google.co.za/scholar_url?hl=en&q=http://www.mdpi.com/1420-3049/19/3/2911/pdf&sa=X&scisig=AAGBfm2BlUDhds_ImVMGAkPiiAjZ0oeMGw&oi=scholaralrt

Increasing emissions of chemical compounds to the environment, especially of pesticides, is one of factors that may explain present honeybee colony losses. In this work, an analytical method employing liquid chromatography-tandem mass spectrometry (LC-MS/MS) was optimized for the simultaneous screening of 19 pesticides which have not been yet determined in honeybee samples from northern Poland (Pomerania). The sample preparation, based on the QuEChERS method combining salting-out liquid-liquid extraction to acetonitrile and a dispersive-SPE clean-up, was adjusted to honeybee samples by adding a small amount of hexane to eliminate beeswax. The recovery of analytes ranged from 70% to 120% with relative standard deviation ≤20%. The limits of detection were in the range of 0.91–25 ng/g. A total of 19 samples of honeybees from suspected pesticide poisoning incidents were analyzed, in which 19 different pesticides were determined.

Hello everyone,

   Kenya is currently in the process of reviewing its current legislation on pest control products, originally from 1982. List member Githaiga Cyrus Wagate is asking for comments on the new bill being proposed (attached below). The proposed bill should fall in line with Kenya's constitution and internationally accepted best practices.