Carbaryl: One Poison for Another in Urban Creeks

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Wed, 06 Jul 2005 20:10:08 GMT

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PANUPS: Carbaryl: One Poison for Another in Urban Creeks

 

 

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.

 

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