PARice’s Recent Comments

• Click here to view comment in original post

  With regard to plastics, I had a chance to talk with Dr. Vom Saal. He said BPA can be in any plastic. But no one really knows which plastics. He also said it may not be the plastic, per se, that is the problem, but the additives, like BPA or phthalates, that are added to the plastic to give it certain properties. He also said the plastics industry had a law passed that keeps anyone from knowing what is in the plastic. Below is a report I did on plastics for a former client, who would not mind if I shared it with you. No. 1, polyethylene phthalate (PETE). 1. This is usually a clear plastic found in soda, water, and vinegar bottles; medicine containers; backing for photography film; 2. There is only a small amount of leaching of phthalates into liquids stored in a PETE bottle, according to Lynn R. Goldman, professor of environmental health at the Johns Hopkins Bloomberg School of Public Health in a New York Times news article, published Jan. 5, 2008. Phthalates, considered by some to be a hormone disrupter, may cause decrease in sperm quality, genital defects, and reproductive impairments in boys, especially, and men and early puberty in girls. Two types of phthalates have been banned in the European Union, Japan, and Argentina. Oregon and other states have considered bans on phthalates. 3. In the same New York Times article above, Frederick Von Saal, a University of Missouri scientist who has studied plastics for years, said that reuse and scratching of PETE bottles can lead to leaching of antimony into the liquid. However, Von Saal points out that researchers don’t know what to look for in plastics because the industry will not tell them everything that is used to manufacture of plastics. Other articles show that there is leaching of other chemicals from PETE, especially if it is heated, but 3. There is little data on its human carcinogencity, according to the World Health Organization’s International Agency for Research on Cancer, which means more research needs to be done. No. 2. High Density Polyethylene (HDPE). 1. This seems to be one of the safest plastics. It is the thick plastic used in containers for detergent, bleach, shampoos, motor oil, newer bullet-proof vests, Tyvek ® envelopes and moonsuits. Usually it comes in cloudy bottles. 2. There is little data on its human carcinogencity, according to the World Health Organization’s International Agency for Research on Cancer. So, right now there is little we can say about it. No. 3, Polyvinyl chloride (PVC) (vinyl chloride is chloroethene, Polyvinyl chloride is chloroethene homopolymer). 1. It is used in many commercial cling wraps, water pipe, gas and sewer drainage, flooring, construction uses (including window frames, doors, wire sheathing), imitation leather, furniture, and vinyl wallpaper. It has been used in baby teethers and squeeze toys, beach balls, bath toys, dolls, knapsacks, raincoats, and umbrellas, those crinkly-sounding plastic trays in boxed cookies or chocolates, candy bar wrappers, and bottles. And there are PVC-covered paper clips). 2. The manufacture of PVC produces dioxins. 3. According to the website, www.inchem.org, a joint effort between the International Programme on Chemical Safety (IPCS) and the Canadian Centre for Occupational Health and Safety (CCOHS), PVC is a human carcinogen with significant exposure to workers and some exposure to the general public (Inchem relied on information from WHO's International Agency for Research on Cancer). From inchem.org: “Several independent but mutually confirmatory studies have shown that exposure to vinyl chloride results in an increased carcinogenic risk in humans, involving the liver, brain, lung and haemo-lymphopoietic system.” 4. Some studies have found higher rates of testicular cancers and a rare form of liver cancer among PVC workers. 5. Phthalates are used to soften PVC in some uses. See entry above under No. 1, polyethylene. 6. From inchem.org, “In one epidemiological study, an excess of foetal (fetal) mortality was reported among wives of workers who had been exposed to vinyl chloride, indicating a possible mutagenic effect in human germ cells.” 7. From inchem.org: “Studies which indicate increased rates of birth defects among the children of parents residing in communities where vinyl chloride production and polymerization plants are located indicate the necessity for further investigation of the teratogenicity of vinyl chloride and its polymers in both animals and humans. A teratogen is something that interferes with fetal development. No. 4 Low Density Polyethylene (LDPE) 1. Used in wrapping films, grocery bags, sandwich bags, food storage bags, “soft” bottles. 2. According to the World Health Organization’s International Agency for Research on Cancer, there are no studies on the carcinogencity of polyethylene. No. 5 Polypropylene (PP) 1. Found in Tupperware, syrup bottles, yogurt tubs, diapers, outdoor carpeting, margarine containers, rigid containers, some baby bottles, cups, and bowls. 2. IARC’s Working Group stated in a paper there was little research done on Polypropylene to determine its carcinogenicity. Although when under-the-skin implantation occurred with PP in rats, sarcomas developed at the site of implantation. No. 6 Polystyrene (PS). 1. Styrofoam, Used in puffy food containers, cups, disposable eating ware (clear and colored), bakery shells, meat trays, cheap hubcaps, packing peanuts and other packing material, and foam insulation. 2. According to IARC’s Working Group, studies were not available on styrofoam’s carcinogenicity, meaning that the studies have not been done but they should be done. However, the IARC report explicitly states “styrene is mutagenic.” From Greenpeace: “Polystyrene is widely used for foam insulation and also for hard applications like cups and toys. Its production involves the use of known (benzene) and suspected human carcinogenic substances (styrene and 1,3-butadiene). Styrene is also known to be toxic to the reproductive system.” No. 7 Various plastics, mostly polycarbonate (bisphenol A) 1. Used in the lining of cans in canned food, hard plastic baby bottles, 5-gallon water bottles, plastic silverware, Lexan products, Nalgene bottles, and plastic supply cups and as a dental sealant. 2. One thing you may not know is that (from Greenpeace) Polycarbonate (Bisphenol A) … is usually made with the highly toxic phosgene, derived from chlorine gas. PC does not need additives but does need solvents for its production, such as methylene chloride, a carcinogen. Other solvents used may include chloroform, 1,2-dichloroethylene, tetrachloroethane and chlorobenzene.”On Ask Umbra on canned and frozen foods posted 3 weeks, 6 days ago 23 Responses

• Click here to view comment in original post

  On the question of freezers, my Physics Group, comprising a professor emeritus of physics at the University of Massachusetts, and a number of former physics students (some of whom are now practicing physicists) said that -- if the freezer door remains closed, there is no difference in the energy cost. The only thing that matters in that determination is the heat exchange between the refrigerator insulation and the outside world. However, the less-than-perfect condition is that the freezer door is opened and closed throughout the day, which means that a full freezer consumes less energy.On Ask Umbra on canned and frozen foods posted 3 weeks, 6 days ago 23 Responses

• Click here to view comment in original post

  I've stopped using all food in cans because you just don't know if it contains BPA before you open it. After you open the can, you can tell because there is a tan or white plastic-looking layer on the cover. Dr. Frederic Vom Saal said that bisphenol A is used in all cans manufactured in the U.S. So the safest bet is to buy food that is in glass jars or frozen. I have to admit, however, that I don't trust the plastic bags used for frozen foods and don't know if the crap in plastic bags leaches into the food in any way.On Ask Umbra on canned and frozen foods posted 4 weeks, 1 day ago 23 Responses

• Click here to view comment in original post

  I'm not a geologist, but I understand that the heat underneath the earth's outermost layer tends to provide upward pressure on the land, so that when you tap the earth's heat, you run the risk of subsidence of the land. Could one of you geologists out there comment on the possibility of subsidence, as well as other risks in tapping geothermal heat energy.

  Thanks.

  On Drill, baby, drill posted 7 months, 2 weeks ago 10 Responses

• Click here to view comment in original post

  I'm not a geologist, but I understand that the heat underneath the earth's outermost layer tends to provide upward pressure on the land, so that when you tap the earth's heat, you run the risk of subsidence of the land. Could one of you geologists out there comment on the possibility of subsidence, as well as other risks in tapping geothermal heat energy.

  Thanks.

  On Drill, baby, drill posted 7 months, 2 weeks ago 10 Responses