Thousands of twelvemonth ago , indigenous people living in the California Channel Islands relied on a manufacture physical process that exposed them to dangerous chemical substance that belike compromised their health . The find depict that toxic nub of our own making have been around for a circumstances longer than we realise .
By replicating a traditional method used to create weewee bottles and other items , a research squad from the University of California , with the aid of research worker from Stockholm University , has shown that native Californians inadvertently and inadvertently exposed themselves to dangerous chemicals known as polycyclic redolent hydrocarbons ( PAHs ) . These compound , which has been tie in to a wide kitchen range of health problems , are a noxious byproduct of warming bitumen , a crude - based nitty-gritty that can be used as a sealer . The detail of this discovery can now be obtain in the skill daybook Environmental Health .
The California Channel Islands are unparalleled in that they ’re one of the few stead in North America where archaeologist can find traces of continuous human occupation date back to when the peopling of the Americas began , up until the Industrial Age . Extensive oeuvre on the island has produced a plentiful and cryptic record of human occupation in the New World , include haggard cadaver that go steady back over 10,000 years . scientist have been able-bodied to trace signs of disease and strain in these skeletons over time , as populations grew in size , as their diet changed , and as societies evolved .
But as the new research shows , certain declines in the wellness of these ancient multitude can likely be trace back to the introduction of bitumen - lined water bottles at least 5,000 years ago , and bitumen - sealed board canoe around 2,000 year ago .
“ Bitumen is composed of chemical substance ( PAHs ) that have been linked to a kind of adverse human health effects , such as cancer , reproductive and developmental deadening , and decreased fetal length and head size , ” study lead generator Sabrina Sholts told Gizmodo . “ We require to know if ancient people confront PAH - related health risks from cultural U.S. of bitumen , as we do today from PAHs in cigarette smoke , polluted zephyr [ and other sources ] . In rules of order to line up out if the level of picture was unsafe ( accord to modern dose limit established by the EPA ) , we had to replicate operation by which bitumen was used — in this showcase , the fabrication and use of goods and services of bitumen - coated water bottles — and try out the resulting PAH concentration in the melody , weewee , and food . ”
To that terminal , Sholts ’ squad engaged in a morsel of experimental archeology . Using the exact unconscious process and tool used by the indigenous Californians , the investigator produced two different version of the ancient water nursing bottle . The first was line with easygoing bitumen known as “ malak , ” which is make out to wash ashore after ooze up from the ocean floor , and the 2d nursing bottle was trace with voiceless bitumen scream “ woqo , ” which is found in oleaginous country sediment .
During the process , the researchers try the atmosphere using gas chromatography and mass spectrometry . They isolate , identify , and calculated levels of PAHs , find concentrations equal to or greater than those incur in coffin nail smoke . But while the fumes from the bitumen were at serious levels , the water stored in the in the bitumen - lined nursing bottle did not contain toxic amounts . accordingly , Sholts says , the amounts of PAHs found in the water supply would n’t have been enough to bring on wellness problems .
“ If someone regularly breathed fumes from melted bitumen — not just for making bottles , but possibly also for making sauceboat , tools , objects for cookery / stash away solid food , [ and other items]—it ’s possible that it could have bring to an adverse wellness consequence at some point during life sentence , peculiarly if there were other sources of exposure , ” said Sholts . “ For instance , PAHs could have been postulate up by fatty solid food and ingested , if the foods were put in in bitumen - stop up shells ( an adaption we can see in the archaeological record ) . cutaneal vulnerability could have happen when bitumen was applied forthwith to the body for ritual or medicinal use . ”
Sholts say that bitumen was readily uncommitted and a highly versatile substance for the people who lived on the Channel Islands , and that further research may provide more info about possible health effects . significantly , this particular risk assessment was only focalize on grownup photo . “ Further assessment would profit from the inclusion of age - specific information and registration broker to account for increase predisposition to PAH exposure during other lifespan , ” said Sholts , adding that the “ health risk would have been higher for children and pregnant women . ”
Sholts let in that no direct grounds of PAHs exist in skeletal clay , since PAHs do not roll up in os ( unlike tether , for example ) and are usually excreted from the body in short after picture . “ However , we see non - specific indicator of stress , such as decreased head size and stature , that are logical with take note effects of prenatal PAH photograph in modern population , ” she said .
Interestingly , she say any of the wellness risks that were encountered through the use of bitumen were believably outweighed by its many advantages for natural selection and well - being . The researchers also teach through this experiment that the kind of bitumen that washes up on the Channel Islands ( from subterranean seeps ) was worthy for making these bottle . Previously , it was suggest that the quality was too inadequate , storm people on the islands to be more hooked on bitumen from the sublunar seeps on the mainland .
In term of next steps , Sholts ’ team plan to continue to use experimental archaeology , toxicology , and other method acting to better understand the health of autochthonal Americans .
A absorbing takeaway from this study is the realisation that fabrication proficiency have been expose hoi polloi to toxin for K of years . Call it the dark side of cleverness .
[ Environmental Health ]
anthropologyArchaeologyScience
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