Mirex in the Environment: Its Degradation to Kepone and Related Compounds

Abstract

The chlorocarbon mirex undergoes slow, successive loss of chlorine in the field to a series of related compounds that had lost one or more chlorine atoms. Soil samples were recovered 12 years after treatment at 1 part per million (ppm), and ant bait was recovered 5 years after an aircraft crash. As much as 50 percent of the original mirex was recovered at levels of about 0.5 and 640 ppm, respectively. Kepone was present at levels of 0.02 ppm in soil and 10 ppm in the bait or up to 10 percent of the recovered mirex, as determined by combined techniques of chromatography and mass spectrometry. This constitutes the first observation of the degradation of mirex in nature, and demonstrates a pathway for its eventual disappearance from the environment.

Natural transformation of chlordecone into 5b-hydrochlordecone in French West Indies soils: statistical evidence for investigating long-term persistence of organic pollutants

“…As an example, in the USA, only 2.2 and 8.5 % of Mirex spreads in a field in 1962, at a concentration of 1 ppm, were recovered 12 years later in the soils of this field under the form of CLD and 5b-hydromirex, respectively (Carlson et al 1976), which are known precursors of 5b-hydroCLD under the action of light and UV Ivie et al 1974). The production of 5b-hydroCLD from these compounds occurs, however, with an extremely slow kinetics, even when sunlight exposure is optimum (Ivie et al 1974), which is obviously not the case of a compound buried in soil.…”

“…Mrema et al 2013;Stockholm convention website 2015). Mirex was expected to oxidize to CLD by photolysis (Ivie et al 1974;Carlson et al 1976). Contamination by CLD was reported in French Polynesia for coral fish (Roche et al 2011) and in whitespotted bamboo shark (Chiloscyllium plagiosum), fished near Hong Kong (Cornish et al 2007).…”

Comparative fate of an organochlorine, chlordecone, and a related compound, chlordecone-5b-hydro, in soils and plants

“…Assessing the fate of these compounds in the environment is also important because another organochlorine pesticide, Mirex, degrades into CLD in the environment (Carlson et al, 1976). Mirex has been extensively used against fire ants and termites and now contaminates ecosystems worldwide (Bloom et al, 2005;Carlson et al, 1976;Luellen et al, 2006;Wang et al, 2010).…”

Historically and Currently Used Dechloranes in the Sediments of the Great Lakes

“…Kepone was reported to form from the degradation of mirex in aquatic environment. 11 In 2009, Kepone was added to the list of the Stockholm Convention as one of the nine "new" persistent organic pollutants.…”