Towards understanding Cameraria ohridella (Lepidoptera: Gracillariidae) development: effects of microhabitat variability in naturally growing horse-chestnut tree canopy.

Dwelling intensity of horse-chestnut miner (Cameraria ohridella) larvae in various leaves insolation and temperature was measured to determine whether this pest's development follows a predictable pattern or depends more on local microenvironment conditions. Mines growing on leaves of mature host plants (Aesculus hippocastanum L.) in their natural conditions were photographed for two consecutive generations of the pest and in two separated vegetation periods. Apart from meteorological data obtained from the nearest station, the temperature of intact and mined parts of sun-exposed and shaded leaf blades was measured at various daytimes throughout the experiment. Obtained sets of digital data were analysed and combined to model mine area growth as a function of degree-days sum by adopting of Verhulst logistic equation. We showed the predictive potential of our model based on experimental data, and it may be useful in the scheduling of pest control measures in natural conditions. Our analyses also revealed that despite significant differences in microenvironment conditions depending on mines' insolation, the horse-chestnut miner larvae could partially compensate for them and complete their development at similar endpoints expressed as the cumulative sum of degree-days. We conclude that computer-aided analysis of photographic documentation of leaf-miner larval growth followed by mathematical modelling offers a noninvasive, reliable, and inexpensive alternative for monitoring local leaf-miners populations.

Long term changes in the concentration of radium in discharge waters of coal mines and Upper Silesian rivers.

According to the latest guidelines of the International Atomic Energy Agency (IAEA, 2016), coal mining is one of the most important contributors to occupational exposure. Coal mining contributes about 45% of the total annual collective dose obtained by workers due to the exposure at places of working. One of the sources of exposure in mining are formation brines with elevated concentrations of natural radionuclides, the most common are radium 226Ra and 228Ra. Radium isotopes often occur in formation waters in underground collieries in the Upper Silesian region (USCB) in Poland. Significant amounts of radium remain underground in the form of radioactive deposits created as a result of spontaneous deposition or water treatment. This phenomenon leads to the increase of radiation hazard for miners. The remaining activities of 226Ra and 228Ra are released into the rivers with mine effluents, causing the contamination of bottom sediments and river banks. The results of radioactivity monitoring of effluents and river waters are presented here to illustrate a trend of long-term changes in environmental contamination, caused by mining industry in the Upper Silesian Region.