enough wasted time over trivialities. see http://www.epa.gov/NCEA/iris/subst/0199.htm
IRIS (Integrated Risk Information System) is a compilation of electronic reports on specific substances found in the environment and their potential to cause human health effects. The information in IRIS is intended for those without extensive training in toxicology, but with some knowledge of health sciences. the home page for IRIS is http://cfpub.epa.gov/ncea/iris/index.cfm
I want to talk about a ubiquitous industrial solvent, TCE, because it is yet to be finally assigned a regulatory maximum contaminant level or MCL. Nevertheless, much is known about TCE to give one pause.
TCE was the major contaminant that was featured in the book and movie A Civil Action -- the Woburn groundwater contamination lawsuit over leukemia deaths among children allegedly caused by pollution from W.R. Grace and Beatrice Foods in Woburn, Mass. The case never made it to a jury. In fact, it turns out the TCE did not come from either company, but that's another story. Grace certainly did violate environmental regulatory laws by burying TCE drums under its Woburn Cryovac building -- but it could not be shown to have caused any cancer deaths among neighborhood children.
TCE used to have a summary in IRIS indicating just how carcinogenic EPA thought the chemical was. But this chemical is so widespread and so much cost, liabiity by the Defense Dept in particular, caused the previous Administration to withdraw that summary "pending further review."
The same thing has been done with a number of potentially dangerous chemicals -- what we call "emerging contaminants" that have not yet had regulatory standards set for them. Chemicals like this include Ammonium Perchlorate and 1,4, dioxane. googling those will bring up some interest stuff.
try that and let's talk about anything that catches your fancy.
for example, on TCE, the Canadian government's site at http://www.ccohs.ca/oshanswers/chemicals/chem_profiles/trichloroethylene/effects_trichloro.html
says, in part:
Short-term exposure to trichloroethylene causes irritation of the nose and throat and central nervous system (CNS) depression, with symptoms such as drowsiness, dizziness, giddiness, headache, loss of coordination. High concentrations have caused numbness and facial pain, reduced eyesight, unconsciousness, irregular heartbeat and death.
Trichloroethylene is noticeable by smell at approximately 82 ppm and above. However, people can become accustomed to the odour and may not smell it until higher concentrations are reached. In one study, exposure to 110 ppm for 8 hours produced fatigue and drowsiness. Other studies have shown no significant effects following exposure to 200 or 300 ppm for less than 4 hours. At 160-250 ppm, the odour is persistent. Lightheadedness has been reported following exposure to 350-400 ppm for 3 hours. At 1000-1200 ppm, the odour is very strong and unpleasant. Lightheadedness, reduced hand-eye coordination and dizziness have been observed after several minutes. At 2000 ppm, the odour is difficult to tolerate, irritation of the nose and throat is strong, and drowsiness, dizziness and nausea occur within 5 minutes. Very high concentrations have produced death due to CNS effects, and, in rare cases, irregular heart beat. In one case, pulmonary edema (a potentially fatal accumulation of fluid in the lungs) was reported. The employee was welding a surface that had been washed in trichloroethylene. The pulmonary edema likely resulted from exposure to phosgene which is formed upon heating of trichloroethylene.
07 Jun '09 03:07
additives
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