(Beyond Pesticides, January 30, 2018) New data from the U.S. Geological Survey (USGS) reveals the year-round presence of neonicotinoids (neonics) in the Great Lakes – the world’s largest freshwater ecosystem. Neonics, which are highly toxic to aquatic organisms and pollinators, are prevalent in the tributaries of the Great Lakes with concentrations and detections increasing during planting season. This new data adds to burgeoning demand for a federal ban of these insecticides in order to safeguard vulnerable aquatic ecosystems and pollinators.
The study, “Year-round presence of neonicotinoid insecticides in tributaries to the Great Lakes, USA,” sampled ten major tributaries to the Great Lakes from October 2015 to September 2016. Neonicotinoids were detected in every month sampled. At least one neonicotinoid was detected in 74 percent of the samples, with 10 percent of samples containing three neonicotinoids. The most frequently detected neonicotinoid was imidacloprid (53%), followed by clothianidin (44%), thiamethoxam (22%), acetamiprid (2%), and dinotefuran (1%).
The detections of clothianidin and thiamethoxam are significantly correlated with the percentage of agricultural land use. Similarly, concentrations increased in the spring and summer months when the planting of neonic-coated seeds and broadcast applications are the highest. For instance, in the agriculturally dominated basin (corn and soybean) along the Maumee River, Ohio, clothianidin, imidacloprid, thiamethoxam are ubiquitously detected in all water samples collected within the basin at the highest recorded for the study; maximum individual neonicotinoid concentration is 330 ng L−1 and maximum total neonicotinoid concentration is 670 ng L−1; median detected individual neonicotinoid concentration is 7.0 to 39 ng L−1. Alternatively, imidacloprid detections significantly increase as the percent of the urbanization increases, where home gardeners and golf courses use neonicotinoid turf and garden products.
Prior to the study, little was known about the chemicals’ presence in the Great Lakes region. From October 2015 to September 2016, USGS researchers took monthly samples from the following rivers that all drain into the Great Lakes: Manitowoc River (WI), Grand River (MI), St. Joseph River (MI), Indiana Harbor Canal (IN), Saginaw River (MI), River Rouge (MI), Maumee River (OH), Cuyahoga River (OH), Genesee River (NY), and Bad River (WI). Michelle Hladik, PhD, lead author of the new study and a research chemist at the USGS, said the major risk of these chemicals is to aquatic insects—an effect that could ripple up the food chain. “If these pesticides are affecting aquatic insects, causing lower populations, it could affect the food chain by removing a food source” for fish, she said.
Neonicotinoids are the most widely used insecticides in the U.S. and have been linked to neurological and immune system impairments in honey bees and other pollinator declines. However, emerging science is also showing that these chemicals are also highly toxic to aquatic organisms, especially aquatic insects on which whole ecosystems rely. Declines in these organisms can, therefore, have catastrophic results for organisms that depend on them for food, including fish and birds.
Last month, the U.S. Environmental Protection Agency (EPA) released preliminary ecological (non-pollinator) assessments for the neonicotinoids clothianidin, thiamethoxam, dinotefuran and the terrestrial ecological assessment for imidacloprid, finding that these pesticides pose both acute and chronic risks to aquatic life and birds. Treated seeds are identified as posing the highest dietary risks to birds, confirming previous research that neonics are highly hazardous not only to bees, but also, to birds, aquatic life, and other non-target organisms. EPA has already released the preliminary pollinator assessment for the neonics, which identifies risks to pollinators from a variety of uses on agricultural crops. The aquatic assessment for imidacloprid, also released last year, finds that it threatens the health of U.S. waterways with significant risks to aquatic insects and cascading effects on aquatic food webs.
Neonics are detected regularly in the nation’s waterways at concentrations that exceed acute and chronic toxicity values for sensitive organisms. As a result of risks to aquatic organisms, the Canadian pesticide regulatory agency has recommended banning imidacloprid, a decision that has been delayed. In Europe, a recent survey finds that streams across the United Kingdom (UK) are contaminated with neonics. The Beyond Pesticides report Poisoned Waterways documents the persistence of neonicotinoids in U.S. waterbodies and the danger they cause to aquatic organisms, resulting in complex cascading impacts on the aquatic food web. The report also highlights current regulatory failures of EPA aquatic standards, which continue to underestimate risks to sensitive species, due to a reliance on test protocols that do not reflect real-world exposures or susceptibilities.
Take Action: Tell EPA that neonics pose unacceptable risks to pollinators, aquatic life, and birds! And, ask your Congressional delegation push EPA to stop the use of neonicotinoids.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Environmental Health News