Claire Coutris
Forsker
Biografi
Claire er forsker på NIBIO siden 2013. Hun har en doktorgrad i miljøkjemi og økotoksikologi fra NMBU og en mastergrad i økologi og økotoksikologi fra Universitet i Toulouse (Frankrike).
Claire er opptatt av å forstå hva som skjer med miljøgifter som havner i jord som følge av menneskelig aktivitet (f.eks. ved bruk av avløpsslam, biorest og plantevernmidler i landbruksjord). Hvor fort brytes uønskede stoffer ned i jord? Hoper de seg opp i planter og i jordorganismer (f.eks. meitemark)? Hvor giftige er de for jordlevende organismer og planter og hva er miljøgiftenes effekter?
Arbeidet inkluderer lab- og feltforsøk, bruk av metoder og instrumenter for å spore miljøgifter og deres effekter på jord og jordorganismer, og samarbeid med andre faggrupper (f.eks. organisk og uorganisk kjemi, molekylærbiologi, mikroskopi).
Sammendrag
Funn fra PROLAND: Soppmidler og mikroplast i jorda Forskerne i PROLAND-prosjektet har undersøkt hva som skjer når soppmidler enten adsorberes på bionedbrytbar plastfolie som blir pløyd ned i jorda, kontra at de blandes direkte i jorda. Har dette noe å si for nedbrytningen av soppmidlene? Forskerne har fulgt nedbrytningsforløpet til tre soppmidler tillatt i norsk landbruk, og har nå svaret… Vi får også et unikt innblikk i hvordan meitemarken – naturens egen jordbearbeider – påvirkes av mikroplast. Hvor lang tid tar det for eksempel før en mikroplastpartikkel passerer gjennom meitemarkens tarm? Temaet er kanskje lite delikat på selveste valentinsdagen, men passer utmerket for oss som er nysgjerrige på mikroplastens mobilitet i jorda.
Sammendrag
Since the 1950s, the use of plastics in agriculture has helped solving many challenges related to food production, while its persistence and mismanagement has led to the plastic pollution we face today. A variety of biodegradable plastic products have thus been marketed, with the aim to solve plastic pollution through complete degradation after use. But the environmental conditions for rapid and complete degradation are not necessarily fulfilled, and the possibility that biodegradable plastics may also contribute to plastic pollution must be evaluated. A two-year field experiment with biodegradable mulches (BDMs) based on polybutylene adipate terephthalate (PBAT/starch and PBAT/polylactic acid) buried in several agricultural soils in mesh bags showed that also under colder climatic conditions does degradation occur, involving fragmentation after two months and depolymerization by hydrolysis, as shown by Fourier-transform infrared spectroscopy. The phytopathogenic fungus Rhizoctonia solani was found to be associated with BDM degradation, and the formation of biodegradable microplastics was observed throughout the experimental period. Between 52 and 93 % of the original BDM mass was recovered after two years, suggesting that accumulation is likely to happen in cold climatic regions when BDM is repeatedly used every year. Mass loss followed negative quadratic functions, implying increasing mass loss rates over time. Despite the range of climatic and edaphic factors, with various agricultural practices and vegetable productions at the study locations, the parameters that significantly favored in situ BDM degradation were higher soil organic matter content and temperatures.
Sammendrag
Food waste collection in Norway is mostly done using plastic bags, made either of polyethylene or, more recently, of biodegradable plastics, which are materials that can be degraded by microorganisms under certain environmental conditions and time frames. Most of the biodegradable plastic bags used in Norway for food waste collection are labelled as compostable, i.e. degradable under composting conditions, but end up in biogas plants and only rarely in composting plants. The present work provides answers to the following questions. First, to what extent are biodegradable plastic bags deteriorated during anaerobic digestion of food waste. Secondly, is the situation different under mesophilic (37°C) and thermophilic (55°C) conditions. Finally, does thermal hydrolysis (THP) pretreatment of food waste containing biodegradable plastic change the results. In tests offering optimal conditions for microorganisms involved in anaerobic digestion, limited deterioration of biodegradable plastics (Mater-Bi® certified as compostable under industrial (ICP) and home (HCP) composting conditions, representative of what is used in Norway for food waste collection for biogas production) was observed, as shown by limited mass loss (14-21 % for ICP and 22-33 % for HCP) and limited changes in the chemical composition after 22 d, a relevant hydraulic retention time for industrial biogas plant operations. Higher mass loss was observed under thermophilic conditions compared to mesophilic conditions. The effect of THP pretreatment of food waste containing biodegradable plastics offered unexpected results: while a small, non-significant increase in mass loss was observed for ICP, THP led to a significantly reduced mass loss for HCP during anaerobic digestion. The biogas process itself was not significantly affected by ICP and HCP present in food waste at a 4 % plastic to food waste ratio. The present research shows that the majority (79-86 % of ICP and 67-78 % of HCP) of biodegradable plastic residues left after initial pretreatment of food waste, will withstand anaerobic conditions, both under mesophilic and thermophilic conditions, also when subjected to THP pretreatment (5 bars, 160°C, 20 min). This strongly suggests that post-treatment of digestate is required to avoid the spread of biodegradable plastics to agricultural soils, for digestates intended for agricultural use.
Divisjon for miljø og naturressurser
PROLAND – Beskytte landbruket mot plastforurensning
I PROLAND undersøker vi kilder til plastforurensning i landbruksjord: avløpsslam, kompost, biorest, landbruksplast og avsetninger fra atmosfæren. Konsentrasjoner av plast, plasttyper og additiver knyttet til plast skal kvantifiseres i landbruksjord fra ulike områder. Videre skal det vurderes hvilke risikoer mikroplast, plastadditiver og plantevernmidler utgjør for jordøkosystemet.
Divisjon for miljø og naturressurser
PROLAND – Protecting agricultural lands from plastic pollution
PROLAND addresses the sources of plastic pollution in agricultural soils: sewage sludge, compost, biogas digestate, agricultural plastics, and atmospheric deposition. The project unfolds pressures of plastic and associated chemical hazards by analyzing their levels in soils and conducting fate and impact studies. It deploys cutting edge “design thinking” methods to co-develop measures for pollution prevention.