Entomopathogenic Nematode <i>Steinernema feltiae</i> as an Indicator of Soil Pollution with Oil Derivatives in Bioremediation Process

Petroleum-derived substances (PDSs) pollutants negatively affect agricultural soil biocenosis, disturbing the biological properties of soils. This paper aimed to test the effect of oil derivatives during soil bioremediation processes on Steinernema feltiae nematode and determine their potential use as an indicator of the degree of soil pollution. Two test series were applied (with bioremediation and without bioremediation) in which the soil was contaminated with diesel fuel, petrol and engine oil. A preparation was designed for the bioremediation of soils polluted with oil derivatives and used in the experiments. Soil pollution with oil derivatives has a negative effect on S. feltiae nematode ability to penetrate Tenebrio mollitor larvae. The most negative and long-lasting effect of soil pollution with oil derivatives was registered when engine oil and diesel fuel were used. The application of biopreparation accelerated the bioremediation process and diminished a negative effect of soil pollution with engine oil on virulence of S. feltiae nematode. The mortality of test insects caused by the nematode S. feltiae was a sufficient indicator of the progress of bioremediation of petroleum pollutants, such as diesel oil and engine oil

Spatial Distribution of Salmonella in Soil near Municipal Waste Landfill Site

Due to the heterogeneous origin of municipal waste, different substrates support the growth of many microorganisms, including those hazardous to humans. In consequence, landfills collecting these refuses are regarded as serious sources of infectious material contaminating the environment. In this study, we aimed to assess how waste may be related to the presence of Salmonella spp. in soil within a landfill and its surroundings. The numbers of these pathogens were estimated in soil samples collected at 17 different stands established in the municipal waste landfill of Barycz (near Krak&oacute;w, Poland) and the surrounding area. The analysis showed that in all soil samples, Salmonella spp. did not exceed 270 cfu g&minus;1 in dry soil (i.e., the active landfill sector). Salmonella spp. was found in 57% of the tested soil samples in spring, 88% in summer, 45% in autumn, and was not detected in winter. A spatial distribution visualized by graphical maps allowed determination of the influence of the active sector on the surrounding areas. The graphical maps showed the impact of seasons on the spread of Salmonella spp. in the soil near the landfill. Detection and estimation of Salmonella spp. distribution in soil within the landfill area distinctly confirms the hazardous impact of collected wastes on hygienic characteristics of the soil

Condition of Young Japanese Knotweed (<i>Reynoutria japonica</i> Houtt.) Offshoots in Response to Microwave Radiation of Their Rhizomes

Invasive Japanese knotweed is one of Poland’s most aggressive and difficult-to-control species. New methods of control are of utmost importance. This study aimed to analyze young knotweed offshoots’ regeneration and physiological condition after treatment of their rhizomes with microwaves of high frequency. The fresh rhizomes were microwaved in the laboratory once for different times (from 5 to 60 s, interval 5 s). Next, in the greenhouse, the growth of offshoots and their biochemical state (spectrophotometry of leaves) were recorded in three measurement series. It was shown that the microwave treatment for 35 s directly destroys knotweed rhizomes of a diameter of 1–3 cm, so it does not produce new offsprings. The treatment times from 5–25 s delay offspring regeneration and growth and development of leaves. The leaves initiate the mechanisms of protection against microwave stress in offshoots grown from the rhizomes exposed to microwaves for 10 s (increase in the anthocyanin index) and the 5 or 20 s treatments (higher values of the photochemical reflectance index). Based on the effective dose (ED50) analysis, the threshold of harmful effects of microwaves on the growth and development of Reynoutria japonica rhizomes was assumed to be 17–19 s