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Organophosphates in the Hula Basin: Atmospheric Levels,
Transport, Degradation Products and Neurotoxic Hazards in Children
Following Low-Level Long-Term Exposure
Organophosphate pesticides (OPs) have been widely used in the Hula Valley. A
significant portion of applied OPs remains suspended in the atmosphere despite the
low volatility. This project assessed the effect of low-level long-term OP exposure on
children and atmospheric levels of key OPs in the valley. Previous studies (1977-87)
showed in-season reversible neurobehavioral effects of OP exposures in residents of
kibbutzim in the valley. This cross-sectional study assessed neurobehavioral outcomes
in 8-12 year-old schoolchildren (n=135) divided into subgroups: (1) those who reside
and study in the Hula Valley (n=51), and (2) those who study in the valley but reside on
the surrounding hills (n=45). In these two sub-groups 84% of the children are "second
generation" of OP exposure, (3) a comparison group (n=39) of age- and sex-matched
schoolchildren living in a different kibbutz in the Rift Valley where OPs have been
minimally used for decades. Cognitive tests were performed. Saliva was sampled to
measure paraoxonase-1 (PON1) gene polymorphisms. Urinary samples were collected
in three consecutive spraying seasons to measure OP metabolites.
Results: An exposure-effect gradient was shown in cognitive tests including Trail B,
Digit Symbol, Digit Cancellation A and Bender Gestalt tests, Purdue Pegboard in two sub-
tests (in both hands and in the subdominant hand). Performance was inversely related to
OP exposure in complex tests that contain scanning and manual dexterity elements. In
parallel, atmospheric concentrations, transport and transformations processes of key OPs
were studied. Measurements of airborne OPs in a few settlements adjacent to agricultural
fields showed spatial and temporal variability; and also indicated that applied pesticides
may reach nearby settlements during application (primary drift) and in the following
few days (secondary drift). Maximal concentrations were observed during application.
A non-steady-state atmospheric dispersion model (CALPUFF) was used in order to
investigate pesticide transport within the valley during the studied application events.
Model results successfully repeated the observed temporal trend but underestimated
OPs air concentrations near field. In addition, laboratory studies of photo-oxidation
of chlorpyrifos (a commonly used OP) adsorbed on various outdoor surfaces (soil,
leaves and glass) were conducted to evaluate the impact of such surface processes on
its environmental fate. The results provide better estimation of atmospheric levels of key
OPs and their derivatives as well as new information on the health hazards of lengthy
exposures to OP drift on children.
Research publications
(1)
Finkelstein,Y., Milatovic, D., Lazarovici, P., Ophir, A., Richter, E.D., Aschner, M., Lecht, S., Marcinkiewicz,
C., Lelkes, P.I., Zaja-Milatovic, S., Gupta, R.C., Brodsky, B., Rosengarten, A., Proscura, E., Shapira, E., &
Wormser, U. (2010). Peaceful use of disastrous neurotoxicants.
NeuroToxicology, 31
, 608-620.
(2)
Finkelstein, Y., Ophir, A., Aschner, M., & Richter, E.D. (2010). Is there a consistent cognitive
and neurobehavioral pattern of toxicity following acute, delayed or chronic exposures to
organophosphates?
NeuroToxicology, 31
, 608-612.
(3)
Finkelstein,Y., Richter, E.D., &Aschner, M. (2011). Epidemiological and clinical studies on acute and chronic
organophosphate-induced neurotoxicity in Israel. In T. Satoh, & R.C. Gupta (Eds.),
Anticholinesterase
pesticides: Metabolism, neurotoxicity, and epidemiology
(pp. 456-457). Hoboken, N.J.: John Wiley & Sons.
Yoram Finkelstein
1
Yael Dubowski
2
Michal Segal-Rosenhaimer
2
Elyakim Doitsch
1
Elihu Richter
3
1. Shaare Zedek Medical Center
in Jerusalem
2. Technion - Israel Institute of
Technology
3. Hebrew University – Hadassah
2009-2013
Multi-Year Research Grants