Is It Safe to Put the Kettle on? — Chromatography Investigates

Modern life is toxic apparently. It is true that toxins are all around us, from the polluted air we breathe to the toxins found in the environment. Was this a problem that affected our ancestors?

Well, a study published in the journal Environmental Health suggests it was. The paper looks at how Native Californian Indians might have been exposed to toxins through their drinking water bottles. Put the kettle on and read on.

Bitumen — not just for roofing

Bitumen is commonly found as a by-product in the petroleum industry. But is also found at the Earth’s surface as a rock or as a viscous liquid found in the sea and on beaches. It is this type of bitumen that Native Californian Indians used for all kinds of applications including fixing arrow heads, making smoke signals and waterproofing containers.

The bitumen was common on the beaches where the Native Californian Indians lived in an area known as the Channel Islands. Archaeological evidence suggests that they were making water vessels using baskets coated in bitumen by at least 5000 years ago. But could this have impacted the health of the Indians?

PAHs are not good for your health

Bitumen contains lots of chemicals known as PAHs — polycyclic aromatic hydrocarbons. The air we breathe is full of PAHs, they come from roads, cigarette smoke and burning hydrocarbons such as in car exhaust gas. Research suggests that they can cause many illnesses including cancer and developmental deficiencies in infants.

So, although we suspect that exposure to PAHs affects modern life — what about our forebears? Very little research has been carried out, which is one of the reasons the team wanted to study the Native Californian Indians. Previous studies have shown that as bitumen use increased, their skeletal remains showed decreases in height and head size. But could that be linked to the increase in PAH exposure?

Baskets like our forebears

The researchers made some baskets and coated them in bitumen. PAH levels were measured in the air near the bottles as they were made. The bottles were then filled with either water or olive oil and left to rest for several months before the liquids were analysed for PAHs using gas chromatography. Using GC to analyse PAHs is discussed in the article, Rapid Screening of Volatile and Semi-Volatile Organic Components in Cocoa Beans and Chocolate Products Using a Portable GC/MS System.

The team found that storing water in the bottles did not cause any of the PAHs to leach out — but storing oil in the bottles did leach out PAHs suggesting foodstuffs stored in bitumen-coated vessels could lead to health problems. Also, the air samples taken during the manufacture of the bottles had levels of PAHs that were equal to or greater than that found in cigarette smoke. Other cultures used bitumen too, so PAHs might have had a role to play in human history — not just modern life.