Day: July 12, 2007

You breathe in toxic chemicals too.

Behind a frigging pay wall, as usual! Kelly et al. argue in Science that hydrophobicity, the tendency to favor oil over water (to break it down to the simplest explanation) is not the only factor that explains biomagnification. The underlying theory used to be that compounds that can dissolve in water would swiftly degrade (either chemically or biologically) and not be of any concern to humans. Compounds like dioxins, PCB’s, DDT, etc. accumulated in fat tissue of aquatic animals and these were the compounds that would biomagnify through ingestion (eating!). Kelly et al. uncover another pathway that probably made every scientist go “D’uh”! – Apparently, chemicals animals breathe in can also bioaccumulate if they are not cleared efficiently by the lungs. So, air breathing cows, chickens and pigs can also cause significant bioaccumulation of certain compounds. Which ones? I guess you’ll have to pay to find out more, but this Scientific American article adds some context. Turns out, it is about 10000 chemicals, not all of them known to be harmful, but because they were never suspect, their metabolism is unknown.

Well, if anything, it will keep the biomonitoring folks busy for a while!

Chemical Consequences — 317 (5835): 165g — Science

Global regulators of commercial chemicals apply a scientific paradigm that relates the biomagnification potential of the chemical in food webs to the chemical’s hydrophobicity. However, Kelly et al. (p. 236; see the news story by Kaiser) show that current methods fail to recognize the food web biomagnification potential of certain chemicals. Certain chemicals do not biomagnify in most aquatic food chains, but biomagnify to a high degree in air-breathing animals, including humans, because of low respiratory elimination. Thus, additional criteria for evaluating biomagnification and toxicity in chemicals that biomagnify are required.

Fundamentalism alive and well in the US

As a card carrying agnostic, my Hindu pride is not shattered, but these people need to get a life. Read the whole article, there’s more about “false gods” and such.

Of course, some Hindus happily accept Jesus as another god, or avatar of some kind, so, fret not O denizens of Saved America, your god has already been assimilated into the Hindu pantheon.

Christian activists disrupt Hindu prayer in US Senate-The United States-World-The Times of India

Christian activists briefly disrupted a Hindu invocation in the US Senate on Thursday, marring a historic first for the chamber and showing that fundamentalism is present and shouting in the US too.

Invited by the Senate to offer Hindu prayers in place of the usual Christian invocation, Rajan Zed, a Hindu priest from Reno, Nevada, had just stepped up to the podium for the landmark occasion when three protesters, said to belong to the Christian Right anti-abortion group Operation Save America, interrupted by loudly asking for God’s forgiveness for allowing the ”false prayer” of a Hindu in the Senate chamber.

“Lord Jesus, forgive us father for allowing a prayer of the wicked, which is an abomination in your sight,” the first protester shouted. “This is an abomination. We shall have no other gods before you.”

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

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.