Article · 2024
The contamination of in situ archaeological remains: A pilot analysis of microplastics in sediment samples using μFTIR
J. M. Rotchell, F. Mendrik, E. Chapman, P. Flintoft, I. Panter, G. Gallio, C. McDonnell, C. R. Liddle, D. Jennings and J. Schofield
Science of The Total Environment 914
An article testing archived and contemporary sediment samples from two York excavations for microplastics, with the particle types and levels found and their implications for preservation in situ.
Rotchell and colleagues analyse archived sediment samples from the Queen's Hotel and Wellington Row excavations in York, together with contemporary cores taken near the sites, to test for microplastics and to consider how such particles move through archaeological deposits. They compare three archived and three contemporary samples from each site, using procedural and air-environment blanks.
Sediments were digested in hydrogen peroxide, density-separated with hypersaline solution, filtered and analysed by μFTIR, which detected particles down to 5 μm (pp. 3–4).
Most of the particles were fragments, and the authors report no significant differences in microplastic levels between samples within either site. They read this as consistent with contamination already present when the archived sediments were collected (pp. 5–6).
Their argument concerns preservation in situ: they present the York results as evidence that microplastics occur in archaeological stratigraphy, and state that effects on organic remains, dating and other analyses need further study (pp. 9–10).
What it records
- The highest level, 20,588 microplastic particles per kilogram, came from the lowest archived Wellington Row sample, at about 7.35 m depth.p. 2
- The Queen's Hotel site, excavated in 1989 and 1990, held 5.33 m of archaeological sediment dating from the late first century CE to the 20th century.p. 3
- The Wellington Row site was excavated in 1988 and 1989, and its archaeological sediments measured 2.91 m in depth.p. 3
- The samples yielded 66 microplastic particles representing 16 polymer types.p. 5
- Wellington Row and Queen's Hotel lie in the River Ouse floodplain, where groundwater monitoring along Tanner Street shows recharge coming principally from the river.p. 7
- Microplastic contamination may compromise the scientific value of archaeological deposits and of the environmental proxies in them, the authors argue.p. 10
Where to read
- Site excavation histories, borehole locations and sediment samplingp. 3
- Sample processing, controls and μFTIR analysispp. 3–5
- Microplastic results and implications for preservation in situpp. 5–10
Contents
- 1. Introduction2
- 2. Methods3
- 2.1. Sediment sample acquisition3
- 2.2. Sediment sample digestion and filtration3
- 2.3. Chemical characterisation of particles using μFTIR analysis3
- 2.4. Quality assurance and control measures4
- 2.5. Statistical analysis5
- 3. Results5
- 3.1. MP abundance levels detected in sediment samples5
- 3.2. MP particle characterisation from sediment samples5
- 4. Discussion6
People, places and institutions
Institutions
- Historic Englandheritage adviser and project funder
Places
- Yorkcity containing both study sites
- Queen's Hotelexcavation and sediment sampling site
- Wellington Rowexcavation and sediment sampling site
- River Ouseriver linked to groundwater recharge
- Tanner Streetlocation of the contemporary core samples
Also named: North Street, Department for Digital, Culture, Media and Sport, Galapagos archipelago, Castell Henllys, UNESCO.
Extent Article 169941, 6 figs, including a plan of the 1980s excavations and boreholes
Defines microplastics (MPs)
RomanMedievalModernLandscape and ClimateSettlementsChronology and DatingTechnology