IOWA DEPARTMENT OF NATURAL RESOURCES
Sept. 6, 2007
For immediate release
1. Lab results indicate pesticide at fault in Shelby County Fish
Kill
2. Iowa air monitors record multiple exceedances of health
standards
LAB RESULTS INDICATE PESTICIDE AT FAULT IN SHELBY COUNTY FISH KILL
MEDIA CONTACT: Alison Manz or Dan Stipe at (712) 243-1934.
HARLAN -Test results indicate that a pesticide was the cause of a fish
kill that occurred Aug. 15 at Little Lake George in Harlan.
Water samples collected from this lake during the investigation show
levels of chlorpyrifos, an insecticide, at approximately 50 times the
toxic level for aquatic life. In four water samples taken at different
locations, the concentrations were 4.6, 4.3, 3.2 and 0.62 parts per
billion. Chlorpyrifos is toxic to fish and other aquatic life at a
concentration of 0.083 ppb.
Marketed for agricultural and household use, this pesticide is used to
control insect pests on row crops and golf courses. It’s also used as
a wood treatment and to kill mosquitoes. Tradenames for chlorpyrifos
include Brodan, Detmol UA, Dowco 179, Dursban, Empire, Eradex, Lorsban,
Paqeant, Piridane, Scout and Stipend. It’s also sold under a number of
generic names.
Chemical residues in drinking water or food are not a concern, but are
extremely toxic to fish and to the aquatic insects like dragonfly larvae
that fish feed upon.
The DNR is continuing to investigate several potential sources of the
chemical that caused the fish kill.
“It’s also uncertain how the chemical reached the lake, although
several possibilities are under investigation,” said Alison Manz, an
environmental specialist at the Atlantic DNR field office. “This just
highlights how important it is for people to store and apply hazardous
chemicals correctly to prevent them from reaching storm sewers or other
waterways.
If they are applying lawn or crop chemicals, it’s vital that they
follow the instructions on the pesticide label, she said.
“Many people don’t realize that when they pour something down a
storm drain on their city street, it goes straight to a nearby stream or
lake,” Manz added.
It doesn’t hurt to leave a buffer of grass around crop fields, watch
weather conditions and avoid applying chemicals before a storm.
Levels of several herbicides were somewhat elevated in the lake,
including atrazine, metolachlor and acetochlor. But they have been ruled
out as a cause of the fish kill.
The DNR’s water monitoring and fisheries bureaus are considering
ongoing monitoring to ensure that chemical levels have dropped.
A DNR fisheries survey on Aug. 31 following the kill found two live
bass but no crappie or bluegill.
“Although the kill is believed to have been caused by chlorpyrifos,
the fish remaining in the lake should be safe to eat,” said John
Olson, water quality specialist with the DNR.
“Chlorpyrifos breaks down relatively rapidly in the environment,”
he added. “And, based on toxicology reports for chlorpyrifos, the
presence of this chemical in Little Lake George should not present a
risk or threat to the health of those who eat fish from this lake.”
The kill claimed an estimated 922 fish, including 710 crappie, 198
bluegill, seven bullheads and seven green sunfish.
Writer: Karen Grimes
# # #
IOWA AIR MONITORS RECORD MULTIPLE EXCEEDANCES OF HEALTH STANDARDS
MEDIA CONTACT: Mindy Kralicek (515) 281-7832, or Sean Fitzsimmons
(515) 281-8923.
The Iowa Department of Natural Resources Air Quality Bureau reported
its monitors recorded exceedances of National Ambient Air Quality
Standards (NAAQS) for pollutants 19 times from Jan. 1 through July 31,
2007. NAAQS are set by the Environmental Protection Agency (EPA) for
seven pollutants considered harmful to public health and the
environment.
The most common culprit was fine particulate matter (PM2.5).
Exceedances of EPA’s PM2.5 standard were monitored in Muscatine seven
times; Clinton three times; Davenport three times, and in Council
Bluffs, Sioux City and Iowa City each one time. For the pollutant levels
recorded, EPA indicates that individuals with respiratory or heart
disease as well as the elderly and children are the groups most at risk,
with increasing likelihood of respiratory symptoms in sensitive
individuals, aggravation of heart or lung disease and premature
mortality in persons with cardiopulmonary disease and the elderly.
High levels of fine particles usually occur under meteorological
conditions where air is stagnant over a multi-state region, trapping
direct fine particle emissions from combustion sources. More fine
particles are added when common airborne pollutants react with
sunlight.
The ozone standard was exceeded one time each in Waverly (north of
Waterloo) and Pisgah (north of Council Bluffs). The standard for coarse
particulate matter or PM10 (particulate matter less than 10 microns in
diameter) was exceeded once in Mason City.
The full report can be accessed at
www.iowadnr.com/air/prof/monitor/monitor.html.
Writer: Mindy Kralicek
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