From: Robina Suwol
Date: 27 Jul 2006
Time: 17:10:27
Remote Name: 69.149.50.230
State agency may curtail use of pyrethroids after discovering runoff is killing
aquatic life.
By Marla Cone, Times Staff Writer
July 14, 2006
Alarmed that popular insecticides that end up in urban streams are killing tiny
aquatic creatures, California's pesticide agency is conducting
a review that is likely to lead to restrictions on many products used on lawns
and gardens.
The chemicals, pyrethroids, are man-made versions of natural compounds in
chrysanthemum flowers. Their use has skyrocketed in the past few years as
U.S. consumers and exterminators search for less-toxic alternatives for
dangerous insecticides already banned. But last fall, a UC Berkeley
scientist reported that pyrethroids are polluting streams in Northern California
suburbs, wiping out crustaceans and insects vital to ecosystems.
Mary-Ann Warmerdam, director of the state Department of Pesticide Regulation,
said Thursday that notices will be sent next month to
manufacturers of about 600 pyrethroid products informing them that the state is
reevaluating their use. That kicks off a process that will probably
culminate in new regulations, and perhaps bans of some products in California.
"We've got the caution flag out," Warmerdam said. "This is a shot across the bow
to the manufacturers that we found a reason for concern and
you need to provide us with data to either eliminate the concern, reformulate
your products or consider taking them off the market."
Allan Noe, a spokesman for CropLife America, representing pesticide
manufacturers, said Thursday that the companies were unaware of California's
intentions but will cooperate with its requests. He said the industry does not
agree that there are toxicity problems but is analyzing the way the
products are used.
"The valuable contributions that pyrethroids make through agricultural and urban
uses are many and these benefits need to be considered," Noe said.
The compounds, particularly one called permethrin, are prevalent in lawn
products and household and pet sprays, as well as in insecticides
sprayed by exterminators and farmers. Also, many cities and counties spray a
pyrethroid for mosquito control to prevent the spread of West Nile virus.
Although they poison nerve cells of invertebrates, the compounds are among the
least toxic insecticides for humans and other mammals as well as
birds. That is why they have replaced the organophosphate insecticides diazinon
and chlorpyrifos, which were phased out by the EPA because they are
particularly hazardous for children.
Use of pyrethroids by California farmers and exterminators has nearly tripled,
growing from about 420,000 pounds in 1999 to 1.1 million pounds in
2004. Consumers' retail sales are not included in those numbers but state
officials say their usage probably doubles that volume.
Donald Weston, an adjunct professor of integrative biology at UC Berkeley, said
his studies have shown that pyrethroids are flowing into
storm drains and building up to toxic levels in stream sediment.
Creeks in the Sacramento suburb of Roseville that contain high pyrethroid levels
are devoid of tiny crustaceans called hyalella, while
nearby streams with low levels are inhabited by them, according to Weston's
study, published in October. In lab tests, nearly all samples of the
pesticide-tainted sediments from the creeks killed the creatures.
The creatures - shrimp-like amphipods that live in bottom sediment - are
important prey for small fish, frogs, salamanders and aquatic insects.
Their presence is often considered a sign of a healthy waterway.
Weston said that the most toxic compound in the creeks is bifenthrin, which is
sprayed around houses by exterminators and is found in some
consumer products that are spread on lawns. He did not find pyrethroids from
farms or mosquito control in the creeks.
About 20% of the Central Valley's streams contain pyrethroid levels that are
toxic to the crustaceans. In addition, they have been detected in
creeks in the Monterey area and the Imperial Valley. No tests have been done in
the Los Angeles region.
Glenn Brank, a spokesman for the state pesticide department, called the
targeting of pyrethroids "definitely the biggest regulatory initiative
ever in California involving pesticides and surface waters."
"It will be the kickoff for regulatory oversight for years to come," he said.
In restricting pyrethroids, however, the state agency hopes to keep some as
options and ensure that people don't switch to products that wind up
being worse.
"We want to do our best to maintain these materials and their viability. They
are relatively safe. They don't pose a human health problem
like these other materials do," Warmerdam said.
The EPA is also reviewing pyrethroids for possible national restrictions.
Consumers can identify pyrethroids in products by checking labels for compounds
that end in "thrin." They are broad spectrum insecticides
effective against a wide variety of flying and crawling insects.
State officials said they will be particularly careful in restricting any
pyrethroids sprayed by vector control agencies, since combating the West
Nile virus, which is spread by mosquitoes, is important.
When manufacturers receive the state notices next month, they must agree within
60 days to begin gathering information about their products'
toxicity and buildup in waterways. If they refuse, the agency will immediately
cancel their products and they cannot be sold in California.
Labels required by the EPA define how much should be used and prohibit
application within 100 feet of waterways. But Warmerdam said the current
warnings may be insufficient because consumers now use large volumes.
"The problem is not the material itself. The real challenge is trying to address
what appears to be misuse and misapplication . We may have to
eliminate products altogether" or require them in different forms less prone to
runoff, she said.
http://www.latimes.com/news/local/la-me-insecticides14jul14,0,4922297.story