Sedimentary cannabinol tracks the history of hemp retting

Abstract

ERODE project funded by the INSU/CNRS and 205 OTARIE project funded by the Région Centre and the European Council. ARTEMIS programInternational audienceHemp (Cannabis sp.) has been a fundamental plant for the development of human societies. Its fibers have long been used for textiles and rope making, which requires prior stem retting. This process is essential for extracting fibers from the stem of the plant, but can adversely affect the quality of surface waters. The history of human activities related to hemp (its domestication, spread, and processing) is frequently reconstructed from seeds and pollen detected in archaeological sites or in sedimentary archives, but this method does not always make it possible to ascertain whether retting took place. Hemp is also known to contain phytocannabinoids, a type of chemicals that are specific to the plant. Here we report on the detection of one of these chemicals, cannabinol (CBN), preserved in a sediment record from a small lake in the French Massif Central covering the last 1800 years. We demonstrate that the presence of this molecule in the sedimentary record is related to retting. Analysis of the evolution of CBN concentrations shows that hemp retting was a significant activity in the area until ca. 1850 AD. These findings are supported by pollen analyses and historical data

Tracking long-term human impacts on landscape, vegetal biodiversity and water quality in the Lake Aydat catchment (Auvergne, France) using pollen, non-pollen palynomorphs and diatom assemblages

“…Historical records from a farm situated in the village of Zanières, located in the Aydat catchment, indicate that crop planting was an important economic activity between 1778 and 1784 AD (Charbonnier, 1984) (AY-7b). Whereas historical sources are almost silent about hemp cultivation and retting, these activities peaked during the 17th and 18th centuries (see more details in Lavrieux et al, 2013b). A striking finding of these data is the long-term and continuous nature of anthropogenic pressure that precluded the regeneration of a forested landscape.…”

“…Blooms of akinetes of Anabaena also coincided with pollen evidence of hemp cultivation from the 5th century AD. This activity spread during the Carolingian period and hemp retting started in Lake Aydat as early as the 12th century (Lavrieux et al, 2013b) (AY-6b). Pollen frequencies of Cannabis and Cannabis-Humulus-type as well as regular notations of the common weeds of this culture (Carduus-type and Cirsium.)…”

“…In addition to the characterisation of the sedimentation model of Lavrieux et al (2013a), focus will be placed on the long-term evolution of the vegetation biodiversity and past water quality changes. In particular, changes induced by agro-pastoral activities or hemp retting which were previously noted by molecular biomarkers and pollen indicators (Lavrieux et al, 2013b).…”

Preliminary report on a mid-19th century Cannabis pollen peak in NE Spain: Historical context and potential chronological significance

“…This distinction, however, is possible using biochemical methods as, for example, the record of cannabiol, a molecule indicative of retting (Lavrieux et al, 2013). Retting is the process by which the fibrous cuticle is detached from the hemp stem to be used as a fibre source.…”

Molecular organic indicators for human activities in the Roman harbor of Ephesus, Turkey

“…Attempts to use organic-geochemical markers in archaeological archives have been reviewed recently by Evershed (2008) and Dubois & Jacob (2016). For example, cannabinol has been identified as an indicator of human impact (Clarke & Merlin, 2013;Lavrieux et al, 2013) related to the usage of hemp. Cannabinol has been identified in a pollen profile from sediments dating back to the Hellenistic period in the Ephesus harbor canal (Stock et al, 2016).…”