In limited toxicological studies, chemicals used in roadside vegetation control have been shown to be harmful to humans, wildlife and the environment. Of the eight most popular herbicides used along California roads, one is confirmed to be a human carcinogen and developmental toxicant, six are identified by the Federal Environmental Protection Agency (EPA) as possible human carcinogens, and three are linked to birth defects. More than half have been found in groundwater and three quarters may pollute the air. Caltrans has refused to pursue further investigation of a controversial 1987 study that found elevated cancers among its employees, or of a 1994 Department of Pesticide Regulation study that showed significant levels of herbicide residue on its applicators' clothing.
Several safe, effective and affordable ways to end the use of health threatening chemical herbicides exist. There are proven nontoxic alternatives to highly dangerous chemicals, such as mowing, planting competitive vegetation, and mulching.
The report by Californians for Alternatives to Toxics (CATs) discloses that Caltrans and county road agencies apply more than 122,000 gallons of herbicide in liquid formulation and 98,000 pounds of dry weedkillers to roadsides in a typical yearÑabout five gallons of liquid and more than two pounds of dry herbicide per road-mile of the 15,000 miles of highways under its jurisdiction. In addition, 51 of the state's 58 county governments also rely on chemical poisons to kill weeds, averaging more than one gallon and one pound of herbicide per mile along the 64,000 miles of roads under county management. Much of the spraying is condensed into a few weeks in late winter and early spring.
The report found that based on the combined herbicide application of Caltrans and county road agencies, people in Los Angeles, Orange, and Contra Costa counties were exposed to the greatest concentration of chemical weedkillers. In stark contrast, no toxic spraying was conducted either by Caltrans or local road agencies in the counties of Mendocino, Humboldt and Trinity, which are located in the most vegetated region of the state.
Eight herbicides account for 86.5% of roadside spraying in California. The federal EPA recognizes six as possible human carcinogens, and four may cause birth defects. Seven, including glyphosate, are linked to toxicity in the liver and blood. Another, oxadiazon, is recognized by state and federal agencies as a liver and kidney toxicant which also causes birth defects and cancer. Seven exhibit varying degrees of toxicity to fish while four are harmful to birds. Four of the toxic chemicals listed have been detected in groundwater by California's Department of Pesticide Regulation.
CATs discovered that most of Caltrans' twelve district offices could not provide a basic summary of their use of toxic herbicides. Caltrans officials in Sacramento are not even sure how much the agency spends on herbicides. Annual expenditures can only be estimated at $4 to $6 million for weedkilling chemicals. The pledge, made in 1992, to reduce use of herbicide by 50% by the year 2000 is unlikely to be met by Caltrans, given the demonstrated level of commitment to this goal.
What You Can Do
Urge your county supervisor to vote against the use of herbicides by Caltrans and by the county.
Copyright Mendocino Environmental Center 1999
Permission granted to excerpt or use this article if source is cited