Aquatic Toxicity Due to Residential Use of Pyrethroid Insecticides
Donald P. Weston; Robert W. Holmes; Jing You; Michael J. Lydy
Abstract
Pyrethroids are the active ingredients in most insecticides available to consumers for residential use in the United States. Yet despite their dominance in the marketplace, there has been no attempt
to analyze for most of these compounds in watercourses draining residential areas. Roseville, California was selected as a typical suburban development, and several creeks were examined that drain subdivisions
of single-family homes. Nearly all creek sediments collected caused toxicity in laboratory exposures to an aquatic species, the amphipod Hyalella azteca, and about half the samples caused nearly complete
mortality. This same species was also found as a resident in the system, but its presence was limited to areas where residential influence was least. The pyrethroid bifenthrin is implicated as the primary
cause of the toxicity, with additional contributions to toxicity from the pyrethroids cyfluthrin and cypermethrin. The dominant sources of these pyrethroids are structural pest control by professional
applicators and/or homeowner use of insecticides, particularly lawn care products. The suburbs of Roseville are unlikely to be unique, and similar sediment quality degradation is likely in other suburban
areas, particularly in dry regions where landscape irrigation can dominate seasonal flow in some water bodies.
Full article appeared in:
Environmental Science and Technology (2005) 39:9778-9784.
Electronic reprint available free of charge here.
