Anikó Seres

Nano szemcseméretű fém-oxidok hatásai a talajban élő kiemelt ökológiai jelentőségű mikroorganizmusokra – Szemle –

Ebben az osszefoglalo cikkben bemutatjuk, hogy a ma mar szeleskorűen alkal-mazott nanomeretű fem-oxidok milyen hatassal lehetnek a talajban elő mikroorga-nizmusokra. A nanomeretű fem-oxidok felhasznalasuk soran kozvetlenul es kozve-tetten is bekerulhetnek a talajba. A leginkabb alkalmazott es ezert kornyezeti kockazat szempontjabol is leggyak-rabban vizsgalt fem-oxidok a nZnO, a nTiO2, a nSiO2, az nAl2O3 es a nCuO. A nanoanyagokat alkalmazhatjak a mezőgazdasagban is, elsősorban novenyvedelmi celbol. A felvezető fem-oxidokat a peszticidek lebontasara is hasznalhatjak a fotokatailitikus tulajdonsaguk miatt. A talajbakteriumokra kifejtett hatasokat szamos kozlemeny vizsgalja. Jelentőse-guk nagy, mivel alapjat kepezik a taplalekhalozatnak es az elsődleges szereplői a globalis biogeokemiai korforgalmaknak. A taplaleklancban betoltott helyzetuk mi-att szerepuk lehet a fem-oxidok felhalmozodasaban is, tehat mindenkepp jol alkal-mazhatoak tesztszervezettkent toxikologiai vagy okotoxikologiai vizsgalatokban. A kis...

Toxicity and uptake of nanoparticulate and bulk ZnO in nematodes with different life strategies

Despite the increasing number and quantity of nanomaterials released in the environment, our knowledge on their bioavailability and possible toxicity to organisms is rather limited. Thus, we know quite little about sensitivity of various nematode feeding types and life strategies to treatments with nano metal oxides. The toxicity of zinc oxide nanoparticles (nano-ZnO) (with a particle size of 25 nm) and the bulk counterpart was investigated in two free-living nematode species of different life strategies: Xiphinema vuittenezi, a K-strategist plant-feeder nematode and Panagrellus redivivus, an r-strategist bacterivor nematode. The internal zinc concentration and the concentration of minor and trace elements were determined by total reflection X-ray fluorescence spectrometry. Concentration-dependent mortality in both nematode species was observed following a 24-h exposure both to nano-ZnO and bulk ZnO. The zinc concentration of the treating suspension had a significant effect on the internal zinc content of the animals in both cases. Particle size did not influence the internal zinc content. Our results show that nano and bulk ZnO have a similar dose-response effect on mortality of the bacterivor P. redivivus. In contrast, the nano-ZnO has stronger toxic effect on the mortality of X. vuittenezi. In general, X. vuittenezi did not react more sensitively to the treatments than P. redivivus, but appeared sensitive to the nano-ZnO treatment compared to bulk ZnO.

Laboratory studies on the effects of a neonicotinoid-containing seed treatment product on non-target soil animals

Cruiser 350 FS (Syngenta) is a widely applied thiamethoxam-containing seed treatment product. Despite of this fact, little is known about its side effects on non-target organisms other than bees. In this study, the effects of Cruiser 350 FS mixed in soil in different concentrations (according to OECD standards) were investigated on the mortality and reproduction of a Collembola species (Folsomia candida). On the basis of springtail mortality data, an LC50 of 223.6 mg/kg and a NOEC of 24.5 mg/kg were determined for Folsomia candida. The following toxicological limits were obtained on the basis of the reproduction data from the springtail test: EC50: 61.73 mg/ kg, NOEC: 12.27 mg/kg. Moreover, mortality tests were performed in microplates on two nematode species of different feeding and reproductive strategies. After 24 hours of exposure, treatment had no effect on mortality up to a concentration of 35 g of thiamethoxam/l in the r-strategist bacterivorous Panagrellus redivivus; while the species-specific LC50 was determined to be 0.19 g/l for Xiphinema vuittenezi. Our results proved the K-strategist plant-feeding X. vuittenezi to be more sensitive than the r-strategist bacterivore P. redivivus. Our results highlight the difference in the sensitivity of nematodes of different feeding and functional groups, suggesting the importance of a more sophisticated study approach.