Effects of nano-sized zero-valent iron (nZVI) on DDT degradation in soil and its toxicity to collembola and ostracods

Nano-sized zero valent iron (nZVI) has been studied for in situ remediation of contaminated soil and ground water. However, little is known about its effects on organisms in soil and aquatic ecosystems. In this study, the effect of nZVI on degradation of DDT and its ecotoxicological effects on collembola (Folsomia candida) and ostracods (Heterocypris incongruens) were investigated. Two soils were used in suspension incubation experiments lasting for 7 and 30 d; a spiked (20 mg DDT kg−1) sandy soil and an aged (>50 years) DDT-polluted soil (24 mg DDT kg−1). These were incubated with 1 or 10 g nZVI kg−1, and residual toxicity in soil and the aqueous phase tested using ecotoxicological tests with collembola or ostracods. Generally, addition of either concentration of nZVI to soil led to about 50% degradation of DDT in spiked soil at the end of 7 and 30 d incubation, while the degradation of DDT was less in aged DDT-polluted soil (24%). Severe negative effects of nZVI were observed on both test organisms after 7 d incubation, but prolonged incubation led to oxidation of nZVI which reduced its toxic effects on the tested organisms. On the other hand, DDT had significant negative effects on collembolan reproduction and ostracod development. We conclude that 1 g nZVI kg−1 was efficient for significant DDT degradation in spiked soil, while a higher concentration was necessary for treating aged pollutants in soil. The adverse effects of nZVI on tested organisms seem temporary and reduced after oxidation.acceptedVersio

Ecotoxicity of nanomaterials used for remediation

Remediation using nanoparticles depends on proper documentation of safety aspects, one of which is their ecotoxicology. Ecotoxicology of nanoparticles has some special features: while traditional ecotoxicology aims at measuring possible negative effects of more or less soluble chemicals or dissolved elements, nanoecotoxicology aims at measuring the toxicity of particles, and its main focus is on effects that are unique to nano-sized particles, as compared to larger particles or solutes. One of the main challenges when testing the ecotoxicity of nanoparticles lies in maintaining stable and reproducible exposure conditions, and adapt these to selected test organisms and endpoints. Another challenge is to use test media that are relevant to the matrices to be treated. Testing of nanoparticles used for remediation, particularly red-ox-active Fe-based nanoparticles, should also make sure to exclude confounding effects of altered red-ox potential which are not nanoparticle-specific. Yet another unique aspect of nanoparticles used for remediation is considerations of ageing of nanoparticles in soil or water, leading to reduced toxicity over field-relevant time scales. This review discusses these and other aspects of how to design and interpret appropriate tests and use these in hazard descriptions for subsequent risk assessments.acceptedVersion30.09.202

Jordlevende sopp

Jordlevende sopp vokser som lange trådformede strukturer kalt hyfer. Når flere hyfer vokser sammen dannes et hvitaktig mycel som vi kan se med det blotte øye. Sopp har ikke klorofyll og må derfor skaffe seg næring på annet vis. Det gjør de ved å hente næring fra organisk materiale i jorda, fra å bryte ned ferske planterester på overflaten og/eller ved å leve i samliv (symbiose)med levende planterøtter (bildet. Selv om man kan se store og små sopper på overflaten, er det alltid slik at mesteparten av soppen finnes under jordoverflaten

Bruk av parasittmidler i landbruk og hestehold

Parasittmidler er viktige for å ivareta god dyrehelse, men økt resistens gjør at virkningen av midlene avtar. I tillegg er parasittmiddel-rester i dyremøkk skadelig både for insekter som lever av møkk, og for mange former for jordliv. Redusert bruk av parasittmidler og riktig håndtering av gjødsla kan bremse resistensutviklingen og bedre situasjonen for gjødselbiller og jordliv.Bruk av parasittmidler i landbruk og hesteholdpublishedVersio

Suppression of the activity of arbuscular mycorrhizal fungi by the soil microbiota

Arbuscular mycorrhizal fungi (AMF) colonise roots of most plants; their extra-radical mycelium (ERM) extends into the soil and acquires nutrients for the plant. The ERM coexists with soil microbial communities and it is unresolved whether these communities stimulate or suppress the ERM activity. This work studied the prevalence of suppressed ERM activity and identified main components behind the suppression. ERM activity was determined by quantifying ERM-mediated P uptake from radioisotope-labelled unsterile soil into plants, and compared to soil physicochemical characteristics and soil microbiome composition. ERM activity varied considerably and was greatly suppressed in 4 of 21 soils. Suppression was mitigated by soil pasteurisation and had a dominating biotic component. AMF-suppressive soils had high abundances of Acidobacteria, and other bacterial taxa being putative fungal antagonists. Suppression was also associated with low soil pH, but this effect was likely indirect, as the relative abundance of, e.g., Acidobacteria decreased after liming. Suppression could not be transferred by adding small amounts of suppressive soil to conducive soil, and thus appeared to involve the common action of several taxa. The presence of AMF antagonists resembles the phenomenon of disease-suppressive soils and implies that ecosystem services of AMF will depend strongly on the specific soil microbiome.publishedVersio

Assessment of the impact of wastewater and sewage sludge treatment methods on antimicrobial resistance. Scientific opinion of the Panel on Microbial Ecology of the Norwegian Scientific Committee for Food and Environment

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Surveillance of antimicrobial resistance in the environment - Scientific Opinion of the Panel on Microbial Ecology, Norwegian Scientific Committee for Food and Environment

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