A California Department of Pesticide Regulation report on sampling of pesticides in the air at elementary schools in the Fresno County community of Parlier during the first quarter of 2006 has been released.
As a part of the California Environmental Protection Agency's Environmental Justice Action Plan, samples of 37 compounds, plus arsenic, copper and sulfur, are being gathered. Air monitoring will continue through December 2006, after which a full analysis will be made and a report will be issued.
DPR sources say enforceable state or federal health standards have not been established for most pesticides in the air. However, for the project, DPR is using “health screening levels” to evaluate potential health effects of chemical exposure.
In naming compounds and their detected levels, DPR officials said a screening level does not indicate the presence or absence of a health hazard, although detections above a certain level suggest a need for further evaluation.
Acrolein, which is used as a biocide and in the manufacturing of other chemicals, was the only volatile organic compound that exceeded health screening levels, but the amounts were similar to those typically found in other areas of the state and were likely from non-pesticidal sources.
Xylene, a solvent used in pesticides, gasoline, cleaners and paints, showed the highest concentration, but it is also thought be from sources other than pesticides.
The chemical with the highest concentration likely resulting from pesticide use was 1, 3-dichloropropene, the active ingredient in Telone II soil fumigant, but it was well below the screening level.
The organophosphate insecticide diazinon was found to be the closest to its screening level. One sample was 75 percent of the screening level but others were lower.
Most frequently detected was another organophosphate insecticide, chlorpyrifos, and samples of it were analyzed at 12 percent of the screening level.
The Parlier project, one of six underway in the state, has objectives of learning if residents are exposed to pesticides in the air, which pesticides in what amounts are involved, and whether the amounts harmful to humans — particularly children. Monitoring, with instruments on rooftops, is done at three elementary schools around Parlier on three consecutive days each week.
The project also has the goals of informing the community of survey results, reducing pesticide risk, evaluating pesticide risk compared with other pollutants monitored, and encouraging growers to use less-toxic alternatives or applying stricter use controls if health concerns emerge.
DPR officials say the Parlier project differs from other studies in that it has a pair of advisory groups. A local advisory group, composed of community organizations, businesses, health providers, grower organizations, growers and PCAs, meets periodically for its input with ideas and opinions on the project. A technical advisory group of governmental agency and university scientists meets several times a year to provide outside scientific review of how DPR is conducting the project.
Another departure from the norm is the series of progress reports issued for the Parlier air sampling. Typically, final results of a project are released only after the research is completed. A public forum on the results is set for the fall/winter of 2007.
Members of both advisory groups recently joined DPR officials for a visit to the 125-acre farm of Parlier grower Ty Parkinson, a participant in a project funded by U.S. EPA and DPR to reduce use of chlorpyrifos, carbaryl, diazinon and methamidophos in nectarines, peaches and plums.
In recent years Parkinson has been using more IPM practices such as trapping to monitor Oriental fruit moth and other stone fruit pests. “In the old days,” he said, “we just used a date of May 15 to routinely spray for OFM, but once we started trapping and working with degree-day hours, it made a lot easier to decide when was the best time to treat.”
Parkinson was an early advocate of using pheromone dispensers for mating disruption on OFM. “It was a big benefit as far as worker reentry times and not worrying about treating for OFM the required number of days before harvest.”
Pointing out that he lives on the ranch and is concerned about the health of his family, Parkinson said his reduced pesticide approach may be more expensive at times than conventional practices but it usually costs about the same.
About 10 years ago, he started using Volck oil as a dormant spray for San Jose scale in place of organophosphate insecticides. Today, he said, his scale problem has been reduced about 95 percent to 98 percent.
“The big drawback for me is I had to slow down the tractor speed to spray the oil and I do all the work myself. It can seem to take forever to get across the ranch,” he said.
After eliminating the organophosphate dormant spray for the scale, Parkinson said he had to find alternatives to manage peach twig borer, obliquebanded leafroller and other pests. He's now using the softer material, Success, instead of Lannate or Carzol.
“Sometimes doing this with softer materials can be a little bit more expensive, but we've gone ahead and bit the bullet. We've been a little innovative and tried to keep in mind what's going on with the environment.
“Still, there may be times that a pheromone doesn't work and we have to make a spray. In those cases, it's just a matter of economics,” he said.
Parkinson continues as a grower cooperator with Walt Bentley, University of California IPM entomologist at Parlier, who has been developing guidelines for a year-round approach to management of stone fruit pests.
The methods have been compiled by Bentley and other UC specialists, U.S. EPA, DPR and the California stone fruit industries.
Founded on “environmentally responsible” practices, the method relies on monitoring key pests and beneficial arthropods on a regular basis. It uses sprays only when monitoring information shows the potential for crop damage. It uses less-toxic pesticides whenever possible, and finally, the approach utilizes broad-spectrum insecticides as a last choice, when environmentally friendly materials are not available.
A guide detailing the steps, from dormancy through post-harvest, is being printed.