Reusing PET(E) Water Bottles

My friend Tim Anderson reuses plastic bottles made of polyethylene terephthalate (PET(E)) to carry his drinking water stored in his truck or boat for longish periods. I told him it wasn't great to drink old water from those bottles, but I couldn't give a good reason why besides the funny taste. I figured since I work at a water science center this is something I should learn about.

After searching on Google Scholar, antimony (Sb) seems to be the main threat of leaching chemicals from the plastic, especially over periods of time and exposure to heat. Sb2O3 is used as the catalyst in the manufacture of polyethylene terephthalate and is probably carcinogenic but there is not good proof according to the WHO ("Although there is some evidence for the carcinogenicity of certain antimony compounds by inhalation, there are no data to indicate carcinogenicity by the oral route.")

Westerhoff et al. (2008) found antimony concentrations in nine brands of commercial bottled water ranged from 0.095 to 0.521 ppb, well below the US Environmental Protection Agency (USEPA) maximum contaminant level (MCL) for Sb of 6 ppb. The average concentration was 0.195+/-0.116 ppb at the beginning of the study and 0.226+/-0.160 ppb 3 months later, with no statistical differences; samples were stored at 22 degrees C. For exposure temperatures of 60, 65, 70, 75, 80, and 85 degrees C, the exposure durations necessary to exceed the 6 ppb MCL are 176, 38, 12, 4.7, 2.3, and 1.3 days, respectively.

Holy cow, does it get to be 140°F in our cars (that's 60°C)? If so, don't leave any bottles of water in there for 176 days. There are 3 or so of these bottles full of refill water in Tim's boat that I think he's planning to drink on his trip back to the mainland that have been stored since October 1. Temps on the island have probably been around 80°, so maybe it gets up to 100 in the hull of the boat... it's sort of in the shade and it's white, reflecting lots of heat.

I made a quick Sb release-curve; if you follow the curve up to the left, I think Tim would have to wait til next summer to have more antimony than the EPA likes in his water.

But there is great variability in Sb release of these bottles depending on who made the bottle! A group of geochemists at the University of Heidelberg headed by William Shotyk (2006) reported antimony in 15 brands of bottled water from Canada and 48 from Europe. They found that waters from a commercial bottling plant in Germany had 0.008 ppb Sb before being bottled. That same brand, when purchased in the store in the PET bottles, had 0.359 ppb (2 orders of mangitude!). After an additional 3 months of storage, the same brand had 0.626 ppb. (I converted reported unit of ng/L assuming it's = 1 ppt.) In 14 brands of bottled water from Canada, Sb concentrations increased on average 19% during 6 months storage at room temperature, but 48 brands of water from 11 European countries increased on average 90% under identical conditions.

We don't know who made Tim's bottles that are sitting in the hull of cuba canoe so we can't guess how much antimony is in them.

Tangent: I'm really curious to find out if these 4 guys made their 11,000 mile voyage on a sailboat made of PET bottles. Their boat is called Plastiki! (Kon Tiki is a wonderful book, I love it.) Oops, just saw their webpage; looks like they are still glueing stuff onto the boat!

Naturalization

Went to the naturalization ceremony today in US District Court. My friend Manohardeep had to renounce India, and I cried a lot. India is so beautiful, he is such an Indian person, he loves India and his parents, and he is so part of Punjabi culture, it sounded so terribly awful:

“I hereby declare, on oath, that I absolutely and entirely renounce and abjure all allegiance and fidelity to any foreign prince, potentate, state, or sovereignty of whom or which I have heretofore been a subject or citizen…”

There were plenty of people from other nice countries too.

The judge was in love with Kate Smith, a singer from the 40s and 50s, so showed two still shots on the overhead of her with the flag as God Bless America played (and some folks sang along), and again she popped up on the screen with flag singing America the Beautiful. He also showed a movie about Ellis Island so they could see how difficult immigration used to be.

Then a speaker from Egypt, who had naturalized in 1996, told funny stories of silly things he did when he first immmigrated (like paying full price for a car). Then he told the folks to "adopt the American values." He said it 2 or 3 times. That was his message (though he never described these values).

Then the judge told them that their kids would not have the accents they have today; their kids would be fully integrated Americans in the future.

The Daughters of the American Revolution, the Sons of the American Revolution, the Board of Elections, Altrusa and other groups had representatives that got to stand up to welcome them as citizens and tell about their group's civic activities that they could get involved in.

Then everyone recited the Pledge of Allegiance, recieved signed certificates and got to get pics with family members in front of the flag and US Seal.

Things opened and closed with a prayer/benediction, Amen.

Everyone went to another room to eat piles of homemade cookies made by older ladies from the aforementioned organizations. One lady tried to recruit me to be a member of Daughters of the Revolution (DAR) because I had told Sylvia that my great grandfather probably descened from a revolutionary family so she wanted me to get involved.

Cell phones were not allowed in the building; you were supposed to "leave them in your car," so I had to bury mine under the mulch behind a building for a few hours.

It was wierd and interesting, let me tell you.