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The rainfall–runoff conceptual model as a cascade of submerged linear reservoirs with particular outflows depending on storages of adjoining reservoirs is developed. The model output contains different exponential functions with roots of Chebyshev polynomials of the first kind as exponents. The model is applied to instantaneous unit hydrograph (IUH) and recession curve problems and compared with the analogous results of the Nash cascade. A case study is performed on a basis of 46 recession periods. Obtained results show the usefulness of the model as an alternative concept to the Nash cascade.

Introduction and objective Fungi belonging to various physiological and morphological groups present in the environment are potential human pathogens. Some of them are considered as emerging pathogens. Therefore, their presence in children’s playgrounds should be regarded as health risk factor. Material and Methods Sixty-eight samples of sand collected from 17 sandpits of different localities in Łódź, Poland, in autumn 2010 and 2011, and in spring 2011 and 2012 were evaluated. The fungi were isolated with classical mycological methods and identified on the basis of morphological and biochemical features. Results The prevalence of fungi in spring was 94.1% of sandpits in both layers of sand (depth 0–3 cm and 10–15 cm) and in one kindergarten sandpit, but only in a deeper layer. In autumn, fungi occurred in both layers in all sandpits (100%). The fungal concentration (CFU/g of sand) varied considerably (range 0 – uncountable) in both layers. A total of 352 isolates belonging to 80 species were found. There were 69 yeasts and yeast-like fungi isolates from 12 species (9 species in each season), and 283 filamentous fungi from 68 species: 35 species in spring and 55 in autumn, with 4 keratinolytic species. There were important causes of allergies, among them Cladosporium herbarum and Alternaria alternata , as well as of opportunistic mycoses: Cryptococcus neoformans, Aspergillus fumigatus and new and ‘emerging’ fungal pathogens e.g., Trichosporon, Rhodotorula, Fusarium and Scedosporium species. Conclusions Potentially pathogenic fungi are present in the sand taken from sandpits in Łódź. This fact poses a significant threat to child health and therefore proper maintenance and periodic checking of sandpits are of great importance.

Introduction and objective The contamination, seasonal and vertical distributions of Toxocara eggs in children’s recreation areas were estimated with respect to their accessibility to domestic and stray animals. Material and Methods During autumn 2011 and spring 2012, a total 88 composite samples of soil/sand (300g each) were taken twice, from 2 depths, from 11 sandpits and 11 play areas situated in the city of Łódź, Poland. From the collected material, 528 samples (20g) were tested using the flotation method. Half the sample sites were secured from access to dogs and cats, while the other half were not. Results The difference in the numbers of positive samples from sandpits and playing areas was significant (χ2=13.72, p=0.0002). The highest rate of contamination was observed in poorly-secured play areas (15.8% of positive samples and 1.2 eggs/100 g of soil/sand). The average density of Toxocara eggs in secured play areas was 6 times less than that found in unsecured areas, while secured sandpits were 3 times less contaminated than those unsecured. The contamination rate was similar in autumn 2011 and spring 2012 (6.4% and 6.8%, respectively). An inverse relationship between the sand/soil depth and number of recovered Toxocara eggs was observed. Additionally, other intestinal helminth eggs (Ancylostomidae, Ascaris spp., and Trichuris spp.) and oocysts of Isospora spp. were also detected from soil samples collected from playing fields. Conclusions The number of Toxocara eggs recovered decreased following fence construction around the examined children’s play areas, but it did not sufficiently prevent the contamination by eggs. These data indicate the necessity for educational programmes which should be implemented for the protection of the local child population from zoonotic infection.

[b]Introduction and objective[/b]. The contamination, seasonal and vertical distributions of [i]Toxocara[/i] eggs in children’s recreation areas were estimated with respect to their accessibility to domestic and stray animals. [b]Materials and methods[/b]. During autumn 2011 and spring 2012, a total 88 composite samples of soil/sand (300g each) were taken twice, from 2 depths, from 11 sandpits and 11 play areas situated in the city of Łódź, Poland. From the collected material, 528 samples (20g) were tested using the flotation method. Half the sample sites were secured from access to dogs and cats, while the other half were not. [b]Results[/b]. The difference in the numbers of positive samples from sandpits and playing areas was significant (c 2 = 13.72, p = 0.0002). The highest rate of contamination was observed in poorly-secured play areas (15.8% of positive samples and 1.2 eggs/100 g of soil/sand). The average density of [i]Toxocara[/i] eggs in secured play areas was 6 times less than that found in unsecured areas, while secured sandpits were 3 times less contaminated than those unsecured. The contamination rate was similar in autumn 2011 and spring 2012 (6.4% and 6.8%, respectively). An inverse relationship between the sand/soil depth and number of recovered [i]Toxocara[/i] eggs was observed. Additionally, other intestinal helminth eggs (Ancylostomidae, Ascaris spp., and Trichuris spp.) and oocysts of [i]Isospora[/i] spp. were also detected from soil samples collected from playing fields. [b]Conclusions[/b]. The number of [i]Toxocara[/i] eggs recovered decreased following fence construction around the examined children’s play areas, but it did not sufficiently prevent the contamination by eggs. These data indicate the necessity for educational programmes which should be implemented for the protection of the local child population from zoonotic infection.