In order to find out if the level of exposure was unsafe (according to modern dose limits established by the EPA), we had to replicate processes by which bitumen was used—in this case, the manufacture and use of bitumen- coated water bottles—and test the resulting PAH concentrations in the air, water, and food.”To that end, Sholts’ team engaged in a bit of experimental archaeology. Using the exact processes and tools used by the indigenous Californians, the researchers produced two different version of the ancient water bottles. The first was lined with soft bitumen known as “malak,” which is known to wash ashore after seeping up from the ocean floor, and the second bottle was lined with hard bitumen called “woqo,” which is found in oily land deposits.
Following oral tradition, the researchers used stone tools and a bird bone awl to weave baskets from soft rush plants found in California. Abalone shells were used as mixing dish, and the bitumen was heated with metavolcanic pebbles before applying the substance to the basket by hand using the bone of a sea mammal. During the process, the researchers sampled the air using gas chromatography and mass spectrometry. They isolated, identified, and measured levels of PAHs, finding concentrations equal to or greater than those found in cigarette smoke. But while the fumes from the bitumen were at dangerous levels, the water stored in the in the bitumen- lined bottles did not contain toxic amounts. Consequently, Sholts says, the amounts of PAHs found in the water wouldn’t have been enough to induce health problems.“If someone regularly breathed fumes from melted bitumen—not just for making bottles, but possibly also for making boats, tools, objects for cooking/storing food, . Dermal exposure could have occurred when bitumen was applied directly to the body for ritual or medicinal purposes.” Sholts says that bitumen was readily available and a highly versatile substance for the people who lived on the Channel Islands, and that further research may provide more information about possible health effects.
Importantly, this particular risk assessment was only focused on adult exposure. The researchers also learned through this experiment that the kind of bitumen that washes up on the Channel Islands (from subterranean seeps) was suitable for making these bottles. Previously, it was suggested that the quality was too poor, forcing people on the islands to be more dependent on bitumen from the terrestrial seeps on the mainland. In terms of next steps, Sholts’ team plans to continue to use experimental archaeology, toxicology, and other methods to better understand the health of indigenous Americans. Hp Pavilion 6700 Laptop Manual here.
A fascinating takeaway from this study is the realization that manufacturing techniques have been exposing people to toxins for thousands of years. Call it the dark side of ingenuity.
WBDG Whole Building Design Guide. The Gateway to Up- To- Date Information on Integrated 'Whole Building' Design Techniques and Technologies.
The goal of 'Whole Building' Design is to create a successful high- performance building by applying an integrated design and team approach to the project during the planning and programming phases. This section pertains to environmental performance of building elements and strategies.