R.I. Roads Sprayed Annually with Herbicides

By TIM FAULKNER/ecoRI News staff

Whether or not you like it, exposure to herbicides is unavoidable if you drive in Rhode Island.

Using truck-mounted hand-sprayers, portions of Rhode Island's 1,100 miles of state roads, highways and bridges are treated with herbicides twice a year by the state Department of Transportation.

This year, the herbicide dicamba, under the commercial name Vanquish, has already been sprayed on roadsides. This synthetic herbicide was applied to road shoulders, curbs and major bridges in late April and early May to prevent the growth of weeds, brush and bamboo.

Glyphosate is sprayed in July to eliminate existing weeds and unwanted plant growth. Both are registered with state Department of Environmental Management (DEM) and legal to use.

In studies, dicamba has shown to cause liver, adrenal gland and reproductive problems in pets and other animals. It is slightly toxic to fish and other aquatic wildlife. It has a half-life of one to four weeks. Although its long-term effects are uncertain, dicamba is highly prone to leaching through soil and into groundwater. Dicamba is not classified as a human carcinogen.

The herbicide Razor, aka glyphosate, is the most common herbicide in the United States and was popularized as the main ingredient in Monsanto's herbicide Roundup. Glyphosate poses a broader range of health risks than dicamba. Glyphosate has shown fetal abnormalities in rats, as well as estrogen and testosterone problems in human embryonic cell studies. It is a suspected endocrin disruptor. It is not considered a carcinogen. 

Studies by the European Union have shown several environmental risks, including toxicity for aquatic organisms. The Environmental Protection Agency (EPA) says prolonged exposure to glyphosates in drinking water can lead to kidney and reproductive "difficulties." It has proved toxic to crustateans and amphibians.

Weeding and mowing are alternatives to control weeds and brush. But Vanquish and Razor are inexpensive alternatives. Vanquish costs $160 for a gallon of concentrate. No more than three gallons of concentrates are needed to apply to the entire state.

Razor is even less expensive at $56 for a gallon of concentrate. Only two or three gallons are needed to create the mixture to treat all state roads.

Public herbicide use also occurs at state parks, the Statehouse grounds and other state-owned lands. Each Rhode Island city and town also relies on pesticides and herbicides to eliminate unwanted bugs and plants from public grounds.

Note: The original version of this article incorrectly stated that all state roads are treated with pesticides. Only problem areas are treated.