Malathion: new thalidomide?

[Joseph R Parrish Jr <JoeParrish@compuserve.com>]

More on malathion:
It's mutagenicity and ability to cause birth defects may be ominous as
noted below.
What will be the statistics over the next nine months in NYC for deformed
infants, 
premature births, and miscarriages, etc.?  Why is no city, state, or
federal agency going to monitor this?
Does this sound like a substance to spray on 7 million people, as has been
done in New York City?
What compound has such a margin of safety other that common table salt?  
EPA's risk management proposal of malathion does not begin until April-June
2000.  
per <http://www.epa.gov/oppsrrd1/op/actionops.htm>
Sounds like someone jumped the gun, with potentially unknown consequences. 
Who gave the go ahead to do so?  
Joe Parrish
NY/NJ Environmental Watch
300 East 56th Street
New York, NY 10022
and
61 Broad Street
Elizabeth, NJ 07201

EPA: "Studies conducted by the University of Southern
    California's Department of Preventive Medicine and others showed no
correlation between
    malathion exposure and sensitive toxic indicators, such as extra risk
of miscarriage or birth
    defects."

versus

Journal of Pesticide Reform  Vol 12(4), pages 29-37

By Loretta Brenner
Loretta Brenner is one of NCAP’s program associates.
The Northwest Coalition for Alternatives to Pesticides (NCAP)
P.O. Box 1393, Eugene, OR  97440
(541) 344-5044, Fax (541) 344-6923
***** Please note new web site address
http://www.pesticide.org

<excerpts>

Malathion is the most commonly detected pesticide in food products in the
U.S. Over seven million malathion products are used in homes, gardens, and
yards in the U.S. annually. Drift and aerial spray eradication programs can
expose children to levels of malathion that can cause illness.

The toxicity of malathion is compounded by its metabolites and
contaminants. Malaoxon, a metabolite produced by the oxidation of malathion
in mammals, insects, plants, and in sunlight, is the primary source of
malathion’s toxicity and is 40 times more acutely toxic than
malathion.14,15  Malathion and malaoxon are more toxic to immature than to
adult rats, due to a slower rate of inactivation of the insecticide in the
livers of immature animals.14 

Residues
Based on U.S. Food and Drug Administration residue analyses, malathion is
the most commonly detected pesticide in food products.98 Malathion residues
were in 18 percent of the 936 food items tested, indicative of its
widespread use in many crops. It is also commonly found in animal feeds. In
1988, EPA estimated that children could be consuming malathion residues
1133 percent in excess, and adults 507 percent in excess, of the amount
currently determined not to cause adverse health affects.1

Mutagenicity
Malathion is mutagenic (causing genetic damage) in human, animal, and
bacteria cells. 
Frequencies of chromosomal aberrations were significantly higher in cotton
field workers exposed to malathion and other pesticides.38,39 (The design
of the study did not permit conclusions about a specific chemical.)
Increased chromosome breaks and aberrations occurred following acute
malathion human poisonings40 and in human blood cells exposed to
malathion.41,42 Malathion caused sister-chromatid exchanges (exchanges of
genetic material within a pair of chromosomes) in human blood cells41-44
and fetal cells.45 
Malathion has also caused mutations in laboratory animals, including mice
and hamsters,46-49 and induced DNA breakage in the bacteria Escherichia
coli.50
In some cases malathion induced genetic damage at doses far below acutely
toxic levels 45,51 and effects can be cumulative.45 

Birth Defects
In humans, maternal exposure to malathion during early pregnancy possibly
caused an almost total absence of skeletal muscle in a developing fetus.52
The mother had repeatedly used a hair lotion containing malathion for
treatment of lice. 
In the San Francisco Bay area, a two-year study examined the relationship
between aerial sprays of malathion for medfly and the occurrence of
congenital anomalies and low birth weights. The researchers found no
definitive associations, but they also admit to limitations in the data and
analysis. However, they did find positive associations between malathion
exposure in individual years and increases in ear anomalies, bowing of leg
bones, clubfoot, and other deformities.53
Malathion has also been associated with birth defects in domestic and
laboratory animals. In rabbits, malathion crosses the placenta and acts on
the central nervous system.54 Injection of malathion into the yolk sac of
chicken eggs caused reduced growth and weakening of a leg bone,55 increased
production of insulin,56 reduced chick weights, reduced hatch, short legs,
bleached down, nerve damage two to six weeks after hatching,57 sparse
plumage, limb shortening, growth reduction, and beak defects.

Synergists
The use of malathion in combination with other pesticides can increase its
toxicity to mammals. These synergistic effects are important because
pesticides are often applied in combination rather than alone. In rats
single low doses of malathion and carbaryl (a carbamate insecticide)
increased certain enzymes that are indicative of cellular damage in the
liver.94 The same combination of pesticides reduced the number of live
fetuses in pregnant rats and also reduced maternal weight gain.95
Combinations of malathion and endosulfan (an organochlorine insecticide)
are more toxic than malathion alone because the combination interferes with
malathion detoxification.96 Diazinon (another organophosphate insecticide)
was also shown to potentiate the toxicity of malathion causing greater
inhibition of cholinesterase in rats than malathion alone.97 

Malathion has been detected in ground and surface water, air, and fog.
Malathion is lethal to beneficial insects, snails, microcrustaceans, fish,
birds, amphibians, and soil microorganisms. 
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