Daily News Archive
October 31, 2006
Town Bends To Public Pressure on Malathion
(Beyond Pesticides, October 31, 2006) Several
years of public pressure has resulted in a decision by the mosquito
district of Paonia, Colorado, to stop the use of malathion for adult
mosquito control. However, the use of the remaining stock of the pesticide
and future mosquito control practices are still up for debate.
Bill Kolb, president of the mosquito district board that serves the
towns of Paonia and Hotchkiss, told the Grand
Junction Daily Sentinel that letters to the editor and appearances
at board meetings by Paonia citizens helped him decide to switch to
a more natural-based substance. Mr. Kolb also stated that the mosquitoes
may have built up some immunity over the last five years it has been
Mr. Kolb conveyed to the Daily Sentinel that he’s not
convinced malathion causes health problems. “There’s nothing
concrete that it does do the bad things they’re saying it does,”
he said. He continued that only three barrels of malathion were used
this year, and most mosquito control was done through killing the insects
at the larval or pupal stage.
However, there are two remaining barrels of malathion. If the board
can return these to Schall Chemical for a refund, they will not fog
with malathion again. However, there is a possibility that malathion
will be used for one more season. A replacement adulticide will be named
is a broad spectrum organophosphate insecticide used to control pests
in agricultural crops, around domestic and comercial buildings and landscapes,
and in public health mosquito control programs. Malathion targets the
nervous system of insects by inhibiting cholinesterase (ChE). Malathion
is classified as having “suggestive evidence of carcinogenicity,”
and published literature studies have shown that malathion can affect
immune function, among other health effects.
Malathion is mobile
in soil and can leach into groundwater and surface waters and impact
public water supplies. Malaoxon, the breakdown product of malathion,
is estimated to be 61 times more toxic to adults than malathion. Malaoxon
is also formed during the water treatment process. According to the
Environmental Protection Agency's (EPA) recent Reregistration
Eligibility Decision (RED) for Malathion, limited monitoring information
indicates that conversion from malathion to malaoxon during the water
treatment process may be as high as 100% and the chemical can remain
stable for 72 hours, which is within delivery times for some publicly
owned treatment works.
Data collected by
the Florida Department of Agriculture and Consumer Services Bureau of
Pesticides (1997) showed only concentrations of malathion entering the
Hillsboro Water Treatment Plant and, following the treatment process,
only concentrations of malaoxon exiting the plant. Once converted, malaoxon
may remain stable in treated water long enough to be available at the
tap for direct consumption.
Local residents disagree with the mosquito control district’s
assessment of malathion effects. Dinah Lindarin of Paonia blamed malathion
for the death of her dog from lung cancer in a letter she wrote to the
Delta County Independent, the area’s local paper. Ms.
Lindarin also said spraying malathion is “extremely ineffective”
and just makes mosquitoes more aggressive.
Paonia residents filed four complaints to EPA in the last five years
with no result. Now, oversight of the mosquito district will be under
the Department of Agriculture. A biological larvicide will be used when
mosquito control starts up in April, Mr. Kolb said, followed this summer
by an adulticide that will be approved by the Department of Agriculture.
Laura Hepting, a
Paonia native now working as special projects coordinator for Beyond
Pesticides, says, “Mosquito spraying is hotly debated in Paonia
– the town is very polarized over the issue. While some people
in the next town over want their property to be included in the spray
zone, others literally head for the hills on the night the truck is
scheduled to pass by their homes. There really needs to be an open dialogue
here and a comprehensive effort to work on effective alternatives to
malathion and adulticiding in general, such as reducing the ample mosquito
breading areas that exist in the North Fork Valley.”
Paonia is not alone. Local municipalities across the country are
working to find ways to improve mosquito control practices. Find out
more through the Alliance
for Informed Mosquito Management.