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PostPosted: Tue Jan 13, 2009 12:47 pm 
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A study published in the September 15 issue of Environmental Science & Technology has found pyrethroid contamination in 100 percent of urban streams sampled. Synthetic Pyrethroids are one of the most widely used consumer pesticides, but recently they have been scrutinized for their resultant health and environmental effects. California is currently reevaluating certain pyrethroid-containing pesticides as a result of increasingly conclusive research.

Entitled “Statewide Investigation of the Role of Pyrethroid Pesticides in Sediment Toxicity in California’s Urban Waterways,” the research included California’s most urbanized regions, as well as the less developed North Coast and Lake Tahoe areas. Thirty creeks in eight regions were selected from 90 screened sites, and bioassays were conducted at two temperatures, 23 and 15 degrees Celsius. Researchers found 25 samples to be toxic at the higher temperature and all 30 at the lower, which is where pyrethroids are more toxic. “Bifenthrin was the pyrethroid of greatest toxicological concern, occurring in all 30 samples,” wrote the team, and the Los Angeles, Central Valley, and San Diego regions showed the most severe contamination. The sampling included analysis for 8 pyrethroids, 30 organochlorine pesticides, and piperonyl butoxide, which helps to make pyrethroids toxic at lower levels.

“It was really good that they did the temperature study,” said Kathryn Kuivila of the U.S. Geological Survey (USGS). The analysis confirmed that pyrethroids were the substance toxic to Hyalella azteca, the small shrimp used in the study. Kuivila and other researchers from USGS will present similar data from seven cities around the United States at a November meeting of the Society of Environmental Toxicology and Chemistry.

A similar study found pyrethroid toxicity in sediments in urban Texas streams. Co-author Jason Belden, Ph.D. said conditions between Texas and California are “different enough to indicate problems [with pyrethroids] across the country.”

Toxicologist Michael J. Lydy, Ph.D., said results like these could occur “any time you find a manicured yard, across the U.S.” This is just one of many reasons to convert public and private lawns and landscapes to organic management, which eliminates synthetic pesticides like pyrethroids. Visit our Lawns and Landscapes program page or our Alternatives fact sheets for tips on organic, Integrated Pest Management, and policy information.

Source: Environmental Science & Technology


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PostPosted: Sun Jun 07, 2009 10:04 am 
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Is pyrethrin a pyrethoid? If not, does any one know its effetiveness as an insecticide?
Also, it seems as though most products that contain pyrethrin also contain piperonyl butoxide. Without this I wonder if pyrethrin is still an effective insecticide.
What are the alternatives?


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PostPosted: Wed Jun 17, 2009 10:27 pm 
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This is from Howard's Note in Jan/Feb 2009 DIRT:

It's time that I make myself very clear on the subject of pyrethrum and PBO. Pyrethrum is a natural material made from the painted daisy (Chrysanthemum cinerariaefolium or Chrysanthemum coccineum). Pyrethrins are the six compounds in pyrethrum that have insecticidal power.

I've been concerned about the misuse of pyrethrum products for some time, and I have never recommended a pyrethrum product that contains other toxic materials. One of the common extra ingredients is PBO, which is a synthetic synergist that gives the basic insecticide more killing power.

As you can read in the Journal of Pesticide Reform (Vol. 22, No. 1), published by the Northwest Coalition for Alternatives to Pesticides, there are scary facets to pyrethrum. The journal says that in laboratory tests, insecticides made from pyrethrum have caused tumors in animals, increased the risk of leukemia, disrupted the normal function of *** horomones, and triggered allergic reactions including heart attack and asthma.

See www.pesticide.org/PyrethrinsPyrethrum.pdf

Because of a recent surge of interest in using pyrethrum for mosquito control, I feel that I need to make my warnings stronger. Pyrethrum and related products are neurotoxins. These days, they are being recommended for use as safe, natural insecticides. The concept of the backyard mosquito mist system in which they are being used is good, but cedar or other biological products should be used instead of neurotoxins. The alternatives work as well, but they don't kill beneficial insects and are considerably less toxic.

In addition, some consultants and quite a few stores and contractors are selling and using combination pyrethrum/diatomaceous earth/PBO products. This concerns me because they are promoting these products as organic, and the idea often is marketed as something that I approve. I do not approve of these products. In my opinion, these pest-control products are in the same unacceptable category as diazinon, Dursban, Sevin and Orthene.

PBO deserves specific comment as well. It shows up in a variety of pesticides, even some orange oil/d-limonene and neem products. These combinations are unacceptable in an organic program. You'll find information about PBO in the Journal of Pesticide Reform, too.

PBO has some of the same toxicity issues as pyrethrum, but it is exponentially worse when mixed with other toxic chemicals to make them more effective at killing bugs. Pyrethrum products are toxic to bees, fish and other aquatic life, but they are even more toxic when PBO is added. For me, pyrethrum no longer is an acceptable insect control in an organic program. Pyrethrum combined with PBO has never been acceptable.

Furthermore, synthetic pyrethroids that also contain PBO are even worse than the "natural" products. Synthetic pyrethroids are similar in chemistry and action to pyrethrum pesticides, but they are a bigger problem for people with allergies and asthma. One of those synthetic pyrethroid products is Scourge, which is being used by Dallas and other cities for mosquito control. Its active ingredients are a pyrethroid called resmethrin and PBO. Some consumer products containing synthetic pyrethroids also are available for the control of ticks, fleas, ants and other insects. I urge you to avoid them.

http://www.dirtdoctor.com/organic/garde ... n/id/2536/


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