Drugs in the water: Behold the power of synergy

Byoliveridley

funky MathES&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.

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  • Obama seeks U.S. carbon emissions cap

    Byoliveridley

    President Barack Obama on Tuesday called on Congress to send him legislation that places a market-based cap on U.S. carbon polluting emissions and pushes the production of more renewable energy.

    In his first speech to a joint session of Congress, Obama said that “to truly transform our economy, protect our security, and save our planet from the ravages of climate change, we need to ultimately make clean, renewable energy the profitable kind of energy.

    Good, Canada will have to harmonize. Stephen Harper was last seen pretending that his “intensity based”” approach was just a “different” way of measuring emissions. You can say that speed and distance are just two ways of measuring travel!

    It is still early and we will see what the US congress can come up with, and what egregious exemptions and offsets it will provide for. Lobbying is already fast and furious. But the news emanating from Obama is promising on the climate change front.

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    Water Find to End Darfur War – Well, not so fast!

    Byoliveridley

    Beware the dangers of the overhyped press release machine (or sciencedaily, pick your poison). All Farouk El-Baz saw when he did the radar study was a giant depression. It is TBD whether there’s water in them thar holes!’

    BBC NEWS | Africa | Ancient Darfur lake is dried up

    Alain Gachet, who used satellite images and radar in his research, said the area received too little rain and had the wrong rock types for water storage. But the French geologist said there was enough water elsewhere in Darfur to end the fighting and rebuild the economy.

    On Wednesday, Boston Universitys Farouk El-Baz said he had received the backing of Sudans government to begin drilling for water in the newly-discovered lake, in North Darfur.

    No wonder they say that water is the 21st century oil. This guy’s going to be drilling for water (also known as well digging!).

  • Scary Energy Consumption Trends

    Byoliveridley

    Per capita energy

    Data courtesy World Resources Institute. As you can see, the people of up and coming powers India and China use barely use 10% the energy per person compared to the US/Canada and will be thirsting for more in the coming years. Of course, they will never get to the same per capita use because population density and crowded housing makes for a lot of energy efficiency.

    China is going coal in a big way. A NY Times article last week spent 5+ pages on this subject. Coal is dirty, dirty, dirty. Coal puts out copious amounts of CO2. Of course, conventional coal fired power plants also pollute in ways that temporarily mask greenhouse effects, both from direct particle emissions and sulfate formation from sulfur in the coal. These effects are localized and temporary, and have pretty serious short term health consequences.

    India is going coal too, being the third largest producer in the world. At least, there is lip service being paid to clean coal/gasification, and increased use of natural gas.

    The world is going to get worse before it gets better…

  • King Coal Country Debates a Sacrilege, Gas Heat

    Byoliveridley

    Hidden in the beginning of an article on a county heavily dependent on coal contemplating a switch to natural gas heating…

    “Heritage should account for something,” said James J. Rhoades, a Republican state senator from Schuylkill County.

    King Coal Country Debates a Sacrilege, Gas Heat – NYTimes.com

    Of course, this argument can be made to defend any practice including child marriage, the caste system, widow burning, slavery, genocide (the list goes on…). Coal is in august company.

    Some of the issues with anthracite:

    But what makes this brittle and lustrous rock, often known as black diamond, so hard and pure is that it is often deeper and under greater pressure than other forms of coal, which also explains why it is expensive and dangerous to extract.

    The anthracite mines in this area have seen more than 30,000 deaths since 1870.

    The argument about local jobs being lost and local economies being damaged is a valid one and needs to be addressed. In theory, destructive practices cannot be continued in order to prop up local economies. But decisions are made locally and it takes a lot of political courage to shutdown a destructive economy and possibly doom a town to fast death. I guess the solution is to provide alternative modes of economy and employment growth during the transition, easier said than done. Problem with being a one horse town, you better hope your horse stays forever young!

    Blogged with the Flock Browser
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    ES&T Online News: E-waste recycling spews dioxins into the air

    Byoliveridley

    ES&T Online News: E-waste recycling spews dioxins into the air

    When computers, televisions, music systems, and other electronic products reach the ends of their lives, they often end up in China or other developing countries as e-waste. Such waste is a serious environmental threat in these parts of the world because of the poorly regulated conditions under which the waste is dismantled. A new study published in ES&T (DOI 10.1021/es0702925) shows that Guiyu, a major e-waste recycling center in China, has the highest documented levels of atmospheric polychlorodibenzo-p-dioxins (PCDDs) and polychlorodibenzofurans (PCDFs) in the world.

    In e-waste recycling centers in China, discarded products are dipped into open pits of acid and heated over grills fueled with coal blocks to extract precious metals, such as gold. These processes often release toxic metals, such as lead, and organic compounds, such as dioxins. The emissions are not regulated, and occupational exposure is high because of the poor working conditions for e-waste recycling laborers.

    In March 2007, researchers at Hong Kong Baptist University showed that soil at e-waste recycling sites in China has high levels of dioxins and polybrominated diphenyl ether (PBDE) flame retardants. (Read the paper at ES&T‘s ASAP website.) More recently, another study published in ES&T showed that the workers at these sites have blood levels of the heavy PBDE, BDE–209, 50–200 times higher than those previously reported. Whereas dioxins are potentially carcinogenic for humans, PBDEs affect thyroid metabolism and brain development.

    In the current study, Ping’an Peng of the Guangzhou Institute of Geochemistry (China) and his colleagues sampled the air from Guiyu for a week in both the summer and the winter and analyzed the samples for 2,3,7,8-PCDD/Fs. The levels varied between 64.9 and 2765 picogram per cubic meter (pg/m3). The toxic equivalents (TEQ)—a value used to account for the different levels of toxicity of the individual dioxins—was 0.909–48.9 pg TEQ/m3. Given that Guiyu has no municipal or medical solid-waste incinerators, which are known to be major sources of dioxins, the authors attributed the elevated dioxin levels to e-waste recycling.

    The team also found that the dioxin concentrations in the air around Guiyu were 12–18 times higher than those in Chendian, a town 9 kilometers (km) from Guiyu, and 37–133 times higher than those in Guangzhou, which is 450 km from the e-waste site. The results suggest that dioxin pollution from e-waste recycling is spreading to nearby areas.

    When they calculated the exposure of adults to dioxins through inhalation, the researchers found that it (68.9 and 126 pg TEQ per kilogram per day in the summer and winter, respectively) was a whopping 15–56 times higher than the World Health Organization recommended maximum of 1–4 pg TEQ/kg/day.

  • BC Carbon Tax regressive?

    Byoliveridley

    British Columbians with low incomes will benefit from the carbon tax in its first year, but will pay more by the scheme’s third year, a new study concludes.

    The impact of the tax and its offsetting income tax cuts will become increasingly unequal unless the provincial government increases payments to low-income earners, the study says.

    The study, by Marc Lee, senior economist with the Canadian Centre for Policy Alternatives, and Toby Sanger, senior economist with the Canadian Union of Public Employees, takes a detailed look at the fairness of the controversial tax.

    via Carbon Tax Whacks the Poor, Later :: News :: thetyee.ca

    The report makes some good points. Revenue neutrality (the offsetting of carbon taxes with income/corporate tax cuts) has nothing to do with reducing carbon emissions. If I were to redesign this tax, I would do as the report says, increase rebates to lower income people, reduce corporate tax cuts so that the resulting revenue can be used to fund more transit infrastructure, energy efficiency infrastructure and the building of a low carbon economy.

    A carbon tax in itself is not sufficient to reduce emissions. It does its part, but building an energy efficient, low carbon infrastructure will do a lot more and the money’s there, just use it.

    You can read the whole report here.