The Story of Stuff

World Water Day – World Water Day

As opposed to every other day when water’s not all that important! But seriously, the site is a good compendium of resources. This year’s theme is coping with scarcity. I remember when Madras had severe water shortages in the late ’80s until a couple of years back. You had to be either very lucky to live in the right neighborhood/rich enough to buy water from private tankers to fill up your water tank. Running water was off and on, we had giant buckets of stored water, it was quite an adventure for me (and a great deal of stress for my parents, of course). Those days still leave a big impression on me. Everytime I leave the tap running for more than 30 seconds, or stand in the shower for longer than necessary, I can hear my mom yelling!

Benzene Levels in Soft Drinks Above Limit – Yahoo! News

WASHINGTON – Cancer-causing benzene has been found in soft drinks at levels above the limit considered safe for drinking water, the Food and Drug Administration acknowledged Wednesday.
Even so, the FDA still believes there are no safety concerns about benzene in soft drinks, or sodas, said Laura Tarantino, the agency’s director of food additive safety.”We haven’t changed our view that right now, there is not a safety concern, not a public health concern,” she said. “But what we need to do is understand how benzene forms and to ensure the industry is doing everything to avoid those circumstances.”

The admission contradicted statements last week, when officials said FDA found insignificant levels of benzene.

In fact, a different study found benzene at four times the tap water limit, on average, in 19 of 24 samples of diet soda.

The formation of benzene in soft drinks is from the reaction of ascorbic acid (aka Vitamin C) and benzoate salts, notably sodium benzoate which is used as a preservative. As the FDA letter states:

We learned that elevated temperature and light can stimulate benzene formation in the presence of benzoate salts and vitamin C, while sugar and EDTA salts inhibit benzene formation.

Is this a pressing concern? First of all, exposure modeling done by the EPA indicates that 93% of all benzene exposure is through inhalation (cigarette smoke, indoor offgassing, that wonderful refueling smell!), with 7% exposure through oral ingestion. So, potentially elevated levels in this 7% fraction are not likely to greatly increase exposure. In addition, the 5 parts per billion level for drinking water is set based on an assumed daily consumption of 2 liters per day (Source – USEPA), a safety factor up from the actual estimated 0.9-1.2 L per day measured consumption. Assuming the average amount of benzene in soda (mainly diet, mind you) is 4 times that of drinking water, a 500 ml dose of diet soda per day is required to equal the dose from drinking water, which mind you, only counts for 7% of the total bezene exposure. So in a sense, a person drinking 2 servings of diet soda per day would exceed the exposure from drinking water at the federally regulated level, and knock the socks off the California standard of 0.13 ppb in water. This will increase his/her known oral exposure. The total exposure to benzene of that individual, however, would not go up significantly because the overwhelming majority of the exposure still occurs through the nose, not through the mouth.

The issue here, and benzene is just the symptom, is that consumers know much more about their drinking water than they do about their manufactured food products, and that is not good for the consumer or for the industry because in the absence of knowledge and full disclosure, both parties are vulnerable. Which is why attempts to limit consumer knowledge hurt everyone.

Conclusion Please don’t stop drinking soda because of this, I am sure you can find plenty of other reasons to limit your soda consumption… Drink lots of filtered tap water, it’s the best!! And, I can assure you that most tap water is tested thoroughly, it’s zero calories and cheap!

ES&T Online News: Can drugs found in water harm humans?

Researchers agree that aquatic species face the greatest risk from exposure to low levels of pharmaceuticals, such as synthetic hormones, which can act as endocrine disrupters at environmental levels. However, little is known about the potential human health effects arising from complex drug mixtures.

Well, it is often more difficult to analyze complex mixtures because Experimental Design 101 makes you want to isolate the effects. And when you do compounds one by one in series, the tendency is to always add them up from the individual experiments. Unfortunately, body chemistry is not like that. I’ve always wanted to design a study that started complex and then tried to isolate later.

To his surprise, Pomati observed that this mixture of drugs at environmental levels inhibited the growth of human embryonic kidney cells. After 48 hours of exposure, cell proliferation was reduced by 10–30% compared with controls. However, no inhibition was observed when cells were exposed to only the toxic cancer drug at environmental levels.

Well, that seems conclusive enough, but here comes the “Experimental Design 101” Scold:

The results show that the growth inhibition is not due to the single most cytotoxic compound alone. But that does not conclusively prove that synergistic or additive effects exist between drugs in the mixture, cautions Thomas Heberer of the Institute of Food Chemistry at the Technical University of Berlin. To show that the individual drugs behave additively, Heberer suggests that researchers should analyze the effects of compounds with a common mode of action, such as antibiotics, alone and in various mixtures.

No, No, and No. Doing this presupposes that you know that mechanism of action, meaning you’ve half answered your question. The question Heberer is trying to answer is “do individual drugs with the same mode of action behave additively”. The question Pomati is trying to answer is “Can we demonstrate cytotoxic effects of a cocktail of drugs at ambient levels in a laboratory setting”? These are two completely different questions and Pomati’s question is more valuable at this point in time. Heberer’s strategy, on the other hand, will keep a lab well funded for years to come! But, it is very much the final step.

It is more important at this point in time to demonstrate other effects such as endocrine disruption, mutagenicity, etc in the lab at environmentally relevant levels of mixtures. Then we can get a better handle on which  effects are relevant and which ones to ignore.

Seriously, for every bit of bad news you read in the New York Times about coal, you read a good news story about the LA Times about coal!

State acts to limit use of coal power – Los Angeles Times

The California Energy Commission on Wednesday imposed new rules that effectively forbid the Los Angeles Department of Water and Power and all other municipal utilities in the state from signing new contracts with coal-fired power plants. The move, together with identical regulations imposed on private utilities in January, is a significant step toward reducing the contribution of California, the world’s sixth largest economy, to global warming.

This is important because California is a huge market and is imposing its market power wisely. It will buy coal power if sequestration actually works.

Technorati Tags: coal, environment

Buried in this abstract from the Environmental Science and Technology Journal is a little titbit about the origin and fate of 90% of all natural estrogens found in water bodies.

Fate, Transport, and Biodegradation of Natural Estrogens in the Environment and Engineered Systems

Another major source, which accounts for 90% of the estrogen load, is animal manure from concentrated animal-feeding operations (CAFOs). Manure is not required to be treated in the United States as long as it is not discharged directly into water bodies. Thus, there is an urgent need to study the fate of animal-borne estrogens from these facilities into the environment. A number of studies have reported the feminization of male aquatic species in water bodies receiving the effluents from wastewater treatment plants (WWTPs) or surface runoff from fields amended with livestock manure and municipal biosolids.

I am not a big fan of hog factories. Clean them up!