TORONTO -- When a group of archeologists excavated reconstructed Iron Age roundhouses that had been used in historical reenactments in Wales for more than 30 years, they expected to learn about the decay processes of these structures.
What they didn’t expect was to discover so much plastic.
More than 2,300 individual pieces of plastic — candy wrappers, straws, a Motorola phone battery, etc. — were found in the ground by archeologists excavating the reconstruction sites.
The Plastic Age encroaching on the Iron Age.
A paper this week dives into the finds, as well as the implications for what future archeological digs could look like, given the ubiquity of plastic in our society today.
THE PLACE
Castell Henllys Iron Age Village is both an archeological site, and a tourist attraction in Wales. The hill fort consists of reconstructed roundhouses that visitors can walk through while learning about the Iron Age, the main draw being that the roundhouses have been reconstructed on the very spot that the structures stood around 2,000 years ago.
As well as attracting tourists, the site is also frequently visited by schools in the area as part of their history teachings on the Iron Age Celts.
But in 2017 and 2018, two reconstructed roundhouses at Castell Henllys came to the end of their heritage life, after 35 and 30 years of use respectively.
The structures were demolished, and the Pembrokeshire Coast National Park — which runs the site — arranged for them to be excavated, “appreciating the value of an archeological perspective for the redesign and rebuilding, and the research significance, of these long-term experimental structures.â€
The roundhouses themselves look like pointy hats resting on the ground, with conical thatched roofs. They were used year-round, and were well-maintained. One even served as the location of a short-lived reality TV show called ‘Surviving The Iron Age,’ in 2001, where participants attempted to live as their ancestors did in the Iron Age.
The first roundhouse, referred to by the site as the Cookhouse, was 9.5 metres in diameter, and was first erected in 1982. It was predominantly used to show what a domestic Iron Age house would’ve looked like, with a central hearth, beds and storage, as well as a portable loom for weaving demonstrations.
“Despite the Cookhouse being the most frequently visited roundhouse at the site, relatively little debris accumulated within it,†the paper stated, adding that this was due to the fact that people visited, walked around, and left, instead of partaking in any activities there that might generate trash.
The second roundhouse, called the Earthwatch roundhouse, was erected in 1984 and contained “curved benches around the hearth […] on which visitors—particularly school parties—could sit.
When the roundhouses were demolished ahead of excavation, the furniture was removed and the roof was taken down, but parts of the standing wall remained, as did debris in the middle of the structure.
THE PLASTIC
The roundhouses had been toured by the public for 30 to 35 years, and all of those years showed in the different types of plastic debris found in the excavation.
In the Cookhouse, archeologists found plastic tags with the word “FERTO" on them — the name of a lake in Hungary. The tags had come with bundles of reeds from Hungary to help build the roundhouses with other, local materials.
A metal bowl with plastic tubs of face paint and a tin of beeswax represented materials that had been used by reconstruction actors in demonstrations over the years.
But much of the plastic in both roundhouses was thought to come from visitors.
The vast majority of the plastic found was in the Earthwatch roundhouse. Researchers suggest this was because it was less well-lit, and visitors spent longer in this space.
“Here, they were told stories about the Iron Age, and, in bad weather, would eat their packed lunches,†the paper stated.
Archeologists found plastic cutlery, and an assortment of food related wrappers, revealing the culinary habits of the schoolchildren and other visitors who came to the roundhouses over the past few decades.
According to the wrappers found, a few visitors had snacked on CheeStrings, Pepperamis and Lunchables pizza.
“A complete Golden Wonder noodles foil lid and two other foil-lid fragments were also found,†the paper stated. "A healthier eating choice is represented by 21 plasticized apple stickers, revealing a range of popular apple varieties, including Braeburn, Cox, Golden Delicious, Granny Smith, Pacific Beauty, Pink Lady and Royal Gala.â€
Other finds included plastic clothing items, one pair of glasses, “an almost complete Godzilla-themed thermos wrapper,†bottle caps, sealing strips for bottles, and plastic straws. One of the most common types of plastic found was the plastic wrapping that affixes straws to drink cartons.
“There were 18 plastic straws and 210 fragments of straw packaging,†the paper said.
Candy wrappers made up the biggest single category, however, with around 1,100 fragments found between both roundhouses.
There was no obvious signs of the plastic having decayed at all, which made sense given the relatively short time period they had been in the ground.
In the Earthwatch roundhouse, some plastic was found trampled into the clay floor itself, packed in. Most debris accumulated around the edge of the structure and underneath furniture, in both roundhouses.
Many of the plastic items were in pieces, or torn in some way, meaning several could belong to the same original plastic bag or wrapper.
“The figures thus represent plastic fragments rather than original plastic or plasticized items,†the paper clarified.
OUR PLASTIC ARCHEOLOGICAL FOOTPRINT
When archeologists in the future look back on our lives now, plastic may be the biggest takeaway and the largest indication of how we lived, this study suggests.
For this specific example, the plastic found at the Earthwatch roundhouse “vividly reveals the consumption of packed lunches by schoolchildren.
“At Castell Henllys, these items comprise the dominant archaeological signature of contemporary heritage-visiting activity,†researchers wrote.
Researchers pointed out that while there has been a lot of research into how plastic winds up in oceans, lakes and rivers, there has been much less research into the plastic presence in terrestrial locations.
Some contemporary archeology studies have noted plastic in areas where it is expected to collect, such as urban areas and landfills, the researchers stated, but “this study concentrates on what might be considered a ‘benign’ environment.â€
These roundhouses — which were built with Iron Age materials and were far away from modern life — were cleaned frequently due to the number of visitors and the year-round use. And yet plastic found its way in.
“The high prevalence of plastic at Castell Henllys is therefore particularly poignant,†the paper said, saying the “sheer quantity of the plastic recovered […] was unexpected.â€
Several scholars have proposed before that the “Plastic Age†should be the term for contemporary society due to how the advent of plastic has changed society so much and become such a staple in every corner of our lives.
While this term has not overtaken others used for our current era, it’s clear that an abundance of plastic in the archeological record may help future archeologists date artifacts and sites.
“With many initiatives now pushing to switch from disposable plastic and plasticized items, this may be a narrow but archaeologically distinctive chronological horizon,†researchers wrote.
