Ryszard Dębicki

Ecotoxicological assessment of residues from different biogas production plants used as fertilizer for soil.

Residues from biogas production (RBP) are a relatively new materials, which may be an interesting resource for the improvement of soil fertility. Nevertheless, in spite of the potential benefits from the agricultural utilization of RBP, there is a need of comprehensive estimation of their toxicity. This information is needed to exclude potential negative environmental impacts arising from the use of RBP. Samples of RBP obtained from six biogas production plants with varied biogas production methods were analysed. The samples with and without separation on solid and liquid phases were investigated. The physicochemical properties of the RBP, heavy metals content (Cr, Cu, Ni, Cd, Pb i Zn) and toxicity on bacteria (Vibrio fischeri, MARA test - 11 different strains), collembolans (Folsomia candida) and two plant species (Lepidium sativum and Sinapis alba) was investigated. Toxicity of RBP was examined using Phytotoxkit F (root growth inhibition), collembolan test (mortality, inhibition of reproduction), Microtox® (inhibition of the luminescence of V. fischeri) and MARA test (growth of microorganisms). An especially negative effect on the tested organisms whereas was noted for the liquid phase after separation. In many cases, RBP without separation also showed unfavourable effects on the tested organisms. Liquid phase after separation and non-separated materials caused inhibition of root growth of L. sativum and S. alba at the level of 17.42-100% and 30.5-100%, respectively, as well as the inhibition of reproduction of F. candida with the range from 68.89 to 100%. In most cases, no ecotoxicological effect was observed for solid phase after separation for tested organisms. The solid phase after separation presented the most favorable properties between all investigated RBP. Therefore, it can be a potential material for the improvement of soil properties and for later use in agriculture.

Land-use impact on selected forms of arsenic and phosphorus in soils of different functions

Abstract The aim of the study was to assess the impact of technosols and geomechanically unchanged soils of the Lublin agglomeration on the concentrations of arsenic and phosphorus, and on selected forms of these elements. Arsenic and phosphorus concentrations were determined in the urban soils of Lublin (Poland), and the relationship between their degree of contamination and different types of land use was estimated. The samples collected were subjected to sequential analysis, using ammonium sulphate, acid ammonium phosphate, oxalate buffer (also with ascorbic acid) and aqua regia for arsenic, and ammonium chloride, sodium hydroxide, hydrochloric acid and aqua regia for phosphorus. The influence of the land use forms was observed in the study. The greatest amount of arsenic (19.62 mg kg−1) was found in the industrial soils of Lublin, while the greatest amount of phosphorus (580.4 mg kg−1) was observed in non-anthropogenic soils (mainly due to the natural accumulation processes of this element). Fractions of arsenic and phosphorus obtained during analysis showed strong differentiation. Amorphic and crystalline fractions of arsenic, bound with iron oxides, proved to have the highest share in the total arsenic pool. The same situation was noted for phosphorus.

The influence of soil granulometric composition on the horology of earthworms

The influence of granulometric composition of fractions from different soil horizons on the qualitative and quantitative composition of earthworms has been studied. The effect of granulometric fractions on the formation of humidity, temperature, gaseous regime, actual acidity as main abiotic factors in genesis of earthworms complexes in the soils of Western Volyn and Podillya has been described.