Fersiynau electronig

Dangosydd eitem ddigidol (DOI)

  • Winnie Courtene-Jones
    University of Plymouth
  • Fannie Burgevin
    University of Bath
  • Liliy Munns
    University of Plymouth
  • Maia B. T. Shillam
    University of Plymouth
  • F De Falco
    University of Plymouth
  • Antione Buchard
    University of Bath
  • Richard D. Handy
    University of Plymouth
  • Richard C. Thompson
    University of Plymouth
  • Mick E. Hanley
    University of Plymouth

In response to the plastic waste crisis, teabag producers have substituted the petrochemical-plastic content of their products with bio-based, biodegradable polymers such as polylactic acid (PLA). Despite widespread use, the degradation rate of PLA/PLA-blended materials in natural soil and their effects on soil biota are poorly understood. This study examined the percentage mass deterioration of teabags with differing cellulose:PLA compositions following burial (-10 cm depth) in an arable field margin for 7-months, using a suite of analytical techniques, such as size exclusion chromatography, 1H nuclear magnetic resonance, dynamic scanning calorimetry, and scanning electron microscopy. The effect of 28-d exposure to teabag discs at environmentally relevant concentrations (0.02 %, 0.04 % and 0.07 % w/w) on the survival, growth and reproduction (OECD TG 222 protocol) of the key soil detritivore Eisenia fetida was assessed in laboratory trials. After 7-month burial, Tbag-A (2.4:1 blend) and Tbag-B (3.5:1 cellulose:PLA blend) lost 66 ± 5 % and 78 ± 4 % of their total mass, primarily attributed to degradation of cellulose as identified by FTIR spectroscopy and a reduction in the cellulose:PLA mass ratio, while Tbag-C (PLA) remained unchanged. There were clear treatment and dose-specific effects on the growth and reproductive output of E. fetida. At 0.07 % w/w of Tbag-A adult mortality marginally increased (15 %) and both the quantity of egg cocoons and the average mass of juveniles also increased, while at concentrations ≥0.04 % w/w of Tbag-C, the quantity of cocoons was suppressed. Adverse effects are comparable to those reported for non-biodegradable petrochemical-based plastic, demonstrating that bio-based PLA does not offer a more 'environmentally friendly' alternative. Our study emphasises the necessity to better understand the environmental fate and ecotoxicity of PLA/PLA-blends to ensure interventions developed through the UN Plastic Pollution Treaty to use alternatives and substitutes to conventional plastics do not result in unintended negative consequences.

Allweddeiriau

Iaith wreiddiolSaesneg
Tudalennau (o-i)172806
CyfnodolynScience of the Total Environment
Cyfrol934
Dyddiad ar-lein cynnar20 Mai 2024
Dynodwyr Gwrthrych Digidol (DOIs)
StatwsCyhoeddwyd - 15 Gorff 2024
Cyhoeddwyd yn allanolIe
Gweld graff cysylltiadau