Use of Rodenticides at High School Raises Issues of Health and Safety
• Misinformation about Chemicals Used Downplays Problem
BY SUZANNE GULDIMANN
A sign posted at Malibu High School last week warning that three restricted use rodenticides are currently in use on the fields surrounding the school to kill ground squirrels has raised numerous concerns in the community.
Families of SMMUSD students received a list with the names of all pesticide products "expected to be applied at school facilities" this year. Parents who wish to be notified of "individual pesticide applications" have the option of filing for a "request for individual pesticide application" from their child's school.
The document lists the following pesticides used by the district: permethrin, phenethyl propionate, piperonyl butoxide, pyrethrins, eugenol, bifenthrin, boric acid, hydramethylnon, bromadiolone, amorphous silica gel, deltamethrin, difethialone, diphacinone, fipronil, chlorfenapyr, cyfluthrin, imidacloprid, aluminum phosphide, zinc phosphide, and glyphosate.
Malibu Mayor Pro Tem Laura Rosenthal was critical of the initial round of concerns.
"I am kind of taking it upon myself to kind of tell you what the issues are," Rosenthal, an outspoken proponent for the SMMUSD said at the Sept. 12 city council meeting. "I want to thank Bob Stallings, our head of Parks and Rec., for helping me with this, as well as speaking to the principal at Malibu High School, as well as speaking with Board of Education members. And, with a little research, this is what the writers could have found out, that there has been a big problem with ground squirrels at MHS. Not on the fields, but in the hillsides, and actually this school had gotten a notice from the county to take care of this problem. That they were running amok, I guess would be a good way to describe it. And that the school district, like our city, like the LAUSD, follows what California safe schools recommends, which is called an IPM, Integrated Pest Management, strategy that focuses on long-term prevention and suppression of a pest problem, with a combo of techniques.
"Because they do use what is called a toxin, they have to put up certain warnings," Rosenthal said. "But I was glad to know that the toxin that they do use is a toxin that is in pellet form, is put down a hole, the holes are covered up, so nothing gets out."
Rosenthal maintained that "the ground squirrels that do eat [the pellets] die, but the poison does not stay in their bodies, so that if they die above ground and another animal eats them, there is nothing left to affect the other animal, whether it be a coyote, a dog, a birds or anything like that." She did not state how the poison vacates an animal's remains, leaving them untainted, or where it goes.
However, Rosenthal's contention that the three poisons listed on the sign at Malibu High School cannot cause secondary poisoning appears to be contradicted by studies and documentation published by numerous government agencies, including the EPA, and the U.S. Department of Agriculture, as well as numerous scientific studies.
Developed in National Socialist Germany in the 1930s, aluminum phosphide, brand name Fumitoxin, one of the three chemicals listed on the MHS sign, was registered for mammal control in 1981, as a fumigant designed for the control of burrowing rodents.
The EPA has placed this rodenticide in its highest toxicity category. As a restricted use pesticide, it can be used by certified personnel only. According to the manufacturer's description, the compound converts to a deadly phosphine gas when it comes in contact with moisture, eventually degrading into inorganic phosphate, which is not toxic to humans but is a groundwater contaminant and contributes to ocean water quality degradation.
According to a U.S. Department of Agriculture report published in 1997, aluminum phosphate has been found to eliminate certain species of ground squirrel, but that "burrowing fumigants will kill animals residing in treated burrows, so it is important to verify that burrows are occupied by target animals. Animals potentially affected by primary poisoning include nontarget rodents, burrowing owls, reptiles and amphibians, rabbits, raccoons, fox, weasel and skunk."
The EPA lists all organophosphates, including aluminum phosphide, as "acutely toxic to bees, wildlife, and humans." Recent studies suggest a possible link to adverse effects in the neurobehavioral development of fetuses and children, even at low levels of exposure.
Fumitoxin is alleged to have caused the death of a four-year-old girl and her 15-month-old sister in 2010 in Utah, after the fumigant leaked into the basement of the girls' home after the defendant used the rodenticide to treat the family's lawn for gophers. According to the allegations, the toxic fumes were spread throughout the house by the air conditioning. The case is currently being heard in Salt Lake City.
Strychnine and diphacionone, the other two rodenticides listed on the warning sign at MHS, are also restricted use pesticides.
Strychnine is a colorless crystalline alkaloid that is a favorite with murder mystery writers because of its high level of toxicity and the fact that it has no specific antidote. It is a well-documented frequent cause of secondary poisoning in cats and dogs, and species like coyote.
Diphacionone is an anticoagulant rodenticide. It has repeatedly been linked to the death of owls, hawks, and other non-target species. There is a growing body of research that links anticoagulants to sarcoptic mange in bobcats and coyotes, a crippling condition that leads to a slow, painful death if not treated.
A study published in March 2011 by scientists from Maryland and Colorado using American kestrels suggests that raptors are at greater risk from poisoning from the rodenticide diphacinone than previously thought.
The research, published in the journal Environmental Toxicology and Chemistry, examines the threat posed by diphacinone as its usage has increased following restrictions on the use of similar pesticides.
"Recent restrictions on the use of some rodenticides may result in increased use of diphacinone," said lead researcher and author Barnett Rattner, of the U.S. Geological Survey. "Very few controlled studies have examined its toxicity in birds, so it is important to determine how lethal this chemical is to wildlife."
"Diphacinone was found to be considerably more toxic to American kestrels than previously reported in tests of other wildlife test species," Rattner wrote.
"The use of these pesticides is another example of the school district's one-size doesn't fit anyone approach," one of the school's neighbors told the Malibu Surfside News. "Santa Monica is an urban environment, western Malibu is not. The district doesn't understand that, and our hawks, owls, bobcats, raccoons, skunks, dogs and children have to pay the price for that. This needs to stop. The City of Malibu is using raptor poles at Trancas to control the gophers. The district needs to look at the alternatives, too."
City of Malibu Public Safety Commissioner Susan Tellem brought the issue up at the panel's September meeting last month.
She requested that the item be placed on the PSC'S October adgenda. She was told by staff that Jim Thorsen, the city manager, would have to decide if the issue was appropriate for the commission to discuss.
"A lot of mothers are upset about this," Tellem said. "Fumitoxin, strychnine and anticoagulants? This is really bad news for the kids. Kids, dogs walk on it, dogs being poisoned. I want to put it on the agenda. This is a major safety issue."
BY SUZANNE GULDIMANN