Репозиторий Университета

© 2020 Cigarette butts (CBs) represent the most common, though poorly biodegradable, type of waste on Earth. Thrown on the soil surface, they can remain unchanged for years, poisoning surrounding ecosystems with toxins accumulated during the smoking process. However, there is practically no data on the effect of smoked CBs on soil biota or soil animals in particular, nor on the potential of edaphic fauna to facilitate their decomposition. One of the most promising agents among soil animals are earthworms, which are known to be beneficial in the processes of recalcitrant organic matter degradation and stimulation of microbial activity in detrital food webs. In a microcosm experiment with the sod podzolic soil, we aimed at testing the effect of the commonly cultured epigeic earthworm Eisenia fetida (Savigny 1826) on the biodegradation rate of CBs and the possible adverse effects of this waste on the species. The experiment had a full-factorial design with three categorical predictors: CB number (0, 1 and 3 per microcosm); smoking condition (smoked and unsmoked CBs) and two levels of earthworm amendment (0 and 4 per microcosm). During 70 days of the experiment, we did not observe any smoked CB-induced mortality of earthworms. The addition of E. fetida significantly increased the CB mass loss across all treatment combinations. Specifically, earthworms improved the decomposition rate from 30 to 36% (p < 0.05), on average. However, this improvement was mainly associated with CB paper wrapping consumption. The inhibition of CO2 emission in microcosms with CBs and earthworms suggested the direct consumption of this waste by E. fetida, rather than modulation of the degradation potential of a microbial community. E. fetida appears to thus be a moderately promising agent for CB biodegradation with the simultaneous reduction in carbon loss from soil through the microbial channel in the studied soil type. These results open perspectives for the further evaluation of the role of soil macroinvertebrates in recalcitrant organic waste management in general and CBs in particular. We demonstrated that earthworms can efficiently decompose smoked and unsmoked cigarette butts regardless of their toxic potential and simultaneously reduce associated microbial activity.

© 2019 Elsevier B.V. Submicrocapsules were prepared from diethylaminoethyl dextran (DEAE-D), xanthan gum (XG) and bovine serum albumin (BSA) on oil cores by ultrasonic treatment. These capsules were modified with poly-L-lysine (PLL) via electrostatic adsorption. The behavior of the capsules was investigated at an air–water interface after their introduction into an aqueous subphase. The interaction of the capsules with 1,2-Dimyristoyl-sn-glycero-3-phosphocholine (DMPC) monolayer formed on the water surface (model cellular membrane) was studied both upon their introduction under the condensed monolayer and with the use of a dilute colloidal solution of the capsules as a subphase. Biodegradation of the proteinaceous capsules with subsequent oil-core release was demonstrated by influence of pronase. The Langmuir lipid monolayer was found to be a good model for investigation of drug release from the capsules in the presence of the cellular membrane.