Regulatory Policy Implications of 1,4-Dioxane - Environmental Investigation and Remediation - page 477

“Green Pharmacy” approach to life-cycle stewardship of pharmaceuticals and personal care prod-
ucts (Daughton, 2003).
While California has established a tradition of pioneering environmental regulatory policies, only
USEPA can implement a nationally unii ed regulatory framework for Green Chemistry. Therefore,
USEPA should lead the way to develop a U.S. national equivalent of Europe's REACH program.
10.7 SHOULD 1,4-DIOXANE BE BANNED?
Given 1,4-dioxane's toxicity and associated groundwater contamination hazard, should all uses of
1,4-dioxane be banned? No. To do so would be to disregard the major advances in industry steward-
ship and regulations governing chemical handling, workplace training, enforcement, manifesting
wastes, monitoring, full accounting of chemicals entering and leaving industrial operations, and
more. These actions and requirements together offer orders of magnitude greater environmental
protection than was in effect at the time most solvent releases occurred. Because methyl chloroform
was banned as an ozone depleting compound by the Montreal Protocol in 1990, and because 90%
of 1,4-dioxane produced in the 1970s and 1980s was used to stabilize methyl chloroform, the total
volume of 1,4-dioxane now in use has been substantially reduced. Moreover, 1,4-dioxane is still
revealing its unique properties to chemical researchers, who continue to i nd innovative uses for the
symmetry of the dioxane ring. One example follows, although 1,4-dioxane has been an agent in
many more chemical discoveries.
Researchers at the University of Edinburgh, Scotland, serendipitously created polymer dough-
nuts while studying potential drug-carrying microparticles. While synthesizing micro-spheres, the
team added 5% of 1,4-dioxane to their usual ethanol solvent. To their surprise, the resulting micropar-
ticles were regular in size and shape, with a hole through the middle, just like a doughnut (see Figure
10.1). Their unique and uniform structure was immediately interesting to the researchers, who tested
the potential usefulness of the dioxane-derived polymer doughnuts as carrier particles for drug
delivery. The dioxane-derived polymer doughnuts showed a high level of liver cell-specii city (94%
uptake rate), leading the team to conduct extensive in vivo testing in mice. Human embryonic kidney
FIGURE 10.1 1,4-Dioxane-derived polymer doughnuts, with potential uses for drug delivery to liver cells, liver
toxicity testing, water i ltration, and other as yet undiscovered applications. (Reproduced from Royal Society
of Chemistry, 2008, Science Daily , June 24. http://www.sciencedaily.com/releases/2008/06/080624120237.
htm [accessed June 25, 2008]. With permission.)