TY - JOUR

T1 - Bracken growth, toxin production and transfer from plant to soil

T2 - a 2-year monitoring study

AU - García-Jorgensen, Daniel B.

AU - Diamantopoulos, Efstathios

AU - Kisielius, Vaidotas

AU - Rosenfjeld, Mette

AU - Rasmussen, Lars H.

AU - Strobel, Bjarne W.

AU - Hansen, Hans Chr B.

PY - 2021

Y1 - 2021

N2 - Background: Bracken fern (Pteridium aquilinum) produces several toxic glycosides, of which ptaquiloside (PTA) is the most well documented. PTA is released from bracken to soil and leaches to surface water and to groundwater. This study presents the first comprehensive monitoring study of bracken biomass, PTA content in the biomass, release by precipitation and concentrations in soil solution at 50 cm depth. Laboratory experiments were carried out to estimate the degradation kinetics of PTA in different soil horizons and moisture contents. Results: The PTA concentration in bracken was highest at the earliest development stages of the plant, i.e., May, declining through the growing season until negligible contents at senescence. The maximum seasonal PTA content in the canopy peaked in early summer, with values up to 1600 mg m−2. Results show that on average 0.2% of the PTA present in the canopy is washed per mm of incident rain, resulting in up to 13.1 mg PTA m−2 being washed off during single rain events. Once in the soil, PTA dissipates rapidly showing a half-lives ranging from 3.3 to 73 h with observed degradation rates showing a tenfold decrease with soil depths increasing from top soil to 25 cm soil depth. Concentrations of PTA in soil solution were positively correlated with the content of PTA in the canopy, with maximum pore water concentrations up to 4,820 ng L−1 during a pulse event taking place in July 2019. Conclusions: The production of PTA in bracken was found to be proportional to biomass growth, while the mass of PTA being released is a function of volume and intensity of precipitation, as well as the bracken development stage. Leaching of PTA takes place in the form of pulses linked to precipitation events, with concentrations in the soil solution exceeding levels which are known to pose a risk to human health.

AB - Background: Bracken fern (Pteridium aquilinum) produces several toxic glycosides, of which ptaquiloside (PTA) is the most well documented. PTA is released from bracken to soil and leaches to surface water and to groundwater. This study presents the first comprehensive monitoring study of bracken biomass, PTA content in the biomass, release by precipitation and concentrations in soil solution at 50 cm depth. Laboratory experiments were carried out to estimate the degradation kinetics of PTA in different soil horizons and moisture contents. Results: The PTA concentration in bracken was highest at the earliest development stages of the plant, i.e., May, declining through the growing season until negligible contents at senescence. The maximum seasonal PTA content in the canopy peaked in early summer, with values up to 1600 mg m−2. Results show that on average 0.2% of the PTA present in the canopy is washed per mm of incident rain, resulting in up to 13.1 mg PTA m−2 being washed off during single rain events. Once in the soil, PTA dissipates rapidly showing a half-lives ranging from 3.3 to 73 h with observed degradation rates showing a tenfold decrease with soil depths increasing from top soil to 25 cm soil depth. Concentrations of PTA in soil solution were positively correlated with the content of PTA in the canopy, with maximum pore water concentrations up to 4,820 ng L−1 during a pulse event taking place in July 2019. Conclusions: The production of PTA in bracken was found to be proportional to biomass growth, while the mass of PTA being released is a function of volume and intensity of precipitation, as well as the bracken development stage. Leaching of PTA takes place in the form of pulses linked to precipitation events, with concentrations in the soil solution exceeding levels which are known to pose a risk to human health.

KW - Bracken fern

KW - Emerging pollutants

KW - Leaching

KW - Monitoring

KW - Phytotoxins

KW - Production

KW - Ptaquiloside

KW - Release

U2 - 10.1186/s12302-021-00484-0

DO - 10.1186/s12302-021-00484-0

M3 - Journal article

AN - SCOPUS:85104077044

VL - 33

JO - Environmental Sciences Europe

JF - Environmental Sciences Europe

SN - 2190-4707

M1 - 45

ER -