trading poisons

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Carbaryl: One Poison for Another in Urban Creeks

July 6, 2005

 

 

 

 

 

 

A recent analysis of contamination in urban creeks has found that homeowners in

the Pacific Northwest have responded to recent bans on lawncare insecticides by

dumping another, equally dangerous pesticide on their lawns. Carbaryl, a likely

carcinogen that attacks the nervous system and is highly toxic to aquatic

invertebrates, is now a major contaminant in creeks in Seattle and Portland.

Sales of the insecticide have also increased, in some areas as much as tenfold,

as bans of lawncare uses of diazinon and chlorpyrifos went into effect in 2003

and 2002. Meanwhile, the U.S. Environmental Protection Agency (EPA) is

concluding its re-registration of carbaryl and proposes to limit only a fraction

of uses, none of which will substantially address the increased stream

concentrations that are now a primary concern for endangered salmon in the

Northwest.

 

 

 

The study, Toxic Tradeoff: Exit Diazinon, Enter Carbaryl, by the Clean Water for

Salmon Campaign, Northwest Coalition for Alternatives to Pesticides (NCAP) and

Washington Toxic Coalition (WTC) compared U.S. Geological Survey (USGS) water

sampling data for two urban creeks in the Pacific Northwest: Thornton Creek in

Seattle and Fanno Creek near Portland. The analysis also looked at sales records

for carbaryl (primarily sold under the product name Sevin) and diazinon in

retail stores in surrounding watersheds. The study focused on diazinon because

chlorpyrifos is not often found in Northwest surface water. Diazinon

concentrations in both creeks decreased between the phaseout period, 2000 to

2004, and generally coincided with a sharp decrease in sales of diazinon in

2002.

 

 

 

Meanwhile, carbaryl sales and stream concentrations followed an opposite

pattern, with sales climbing in 2002 and sampling data indicating more frequent

detections in higher concentrations than ever before. National Academy of

Science guidelines recommend that aquatic carbaryl concentrations not exceed

0.02 parts per billion. At Thornton Creek in 2002, four water samples detected

carbaryl at levels between 0.054 to 0.48 ppb. Since then, five other samples

have shown concentrations greater than the NAS guidelines. The study attributed

the higher sales to use of granular formulations to control crane flies on

residential lawns.

 

 

 

Carbaryl is a broad spectrum insecticide that inhibits the functioning of the

nervous system and is widely used in agriculture and in residential landscaping.

First registered for use by the EPA in 1959, the insecticide was targeted for

review as early as 1972, when stronger health and environmental protections were

incorporated in FIFRA (Federal Insecticide, Fungicide and Rodenticide Act). EPA

is finally addressing carbaryl risks, with a draft interim registration decision

(IRED) issued in 2003 that proposes no major changes for agricultural uses and

will not eliminate the granular applications on lawns that are most problematic

for fish and people in the Pacific Northwest. The EPA has recommended phasing

out some residential garden and pet applications because they pose unacceptable

exposure risks to infants and toddlers.

 

 

 

Multiple studies have reported greater incidence of childhood brain cancer in

homes where carbaryl or products that may contain carbaryl are used and elevated

risks of non-Hodgkins lymphoma among farmers using carbaryl. Laboratory studies

have also found carbaryl an especially potent inhibitor of immune system

responses, and found it mimics the hormones estrogen and progesterone.

 

 

 

The report faults the EPA environmental review of impacts on endangered salmon,

noting the agency issued a " not likely to affect " determination for carbaryl on

Puget Sound Chinook, despite the USGS data on rising concentrations in salmon

streams. The agency has recently announced it will re-do its effects

determination, but it is not clear if the new evaluation will incorporate

important evidence of sub-lethal impacts that the agency has previously ignored,

such as reducing the ability of salmon to metabolize food and resist parasites

or the impacts of carbaryl on the aquatic invertebrates that are a major source

of food for salmon.

 

 

 

Once the EPA phaseout of residential uses of diazinon and chlorpyrifos began to

take effect, manufacturers aggressively marketed carbaryl as a replacement.

Toxic Tradeoff reports that mailers for Sevin were sent to Master Gardeners

around the country in 2004, offering a free ten-pound bag of the granular

formulation to " test on your lawn or use in field trials. " Manufacturers also

continue to promote insecticides containing pyrethroids, which are also harmful

to aquatic life.

 

 

 

Not willing to stand by while pesticide manufacturers dangle substitute

pesticides in front of consumers, local governments concerned about water

quality impacts in the Pacific Northwest have developed consumer advisories for

non-toxic lawn care. The report suggests that EPA should take a page from these

local efforts and encourage use of these established, non-chemical alternatives

for lawn care.

 

 

 

EPA closed a public comment period for modifying all tolerances for food

residues of carbaryl as recently as May 31, 2005. Research on alternatives to

carbaryl and full evaluation of the ecological and human health risks of

carbaryl products are commonsense steps EPA could take to stop the toxic

tradeoff of one toxic pesticide for another.

 

 

 

Sources: Toxic Tradeoff, Exit Diazinon, Enter Carbaryl,Phaseout Leads to Risk

Replacement, Erika Schreder and Philip Dickey, A Clean Water for Salmon Campaign

report, May 2005, Washington Toxics Coalition, http://www.watoxics.org; US EPA

IRED, Carbaryl, REDs and Pesticide Re-registration Status,

http://www.epa.gov/pesticides.

Contact: WTC, info, (202) 632-1545, PANNA.

 

 

" God was my co-pilot, but we crashed in the Andes and I had to eat him. "