3D printed receptacle with diffuser membrane for manipulating pressurized air and water.

Water research is one of many fields where fused filament fabrication 3D printing offers the freedom of customization and the inclusion of commercial components. We present our 330 mL 3D printed laboratory receptacle that has been customized to control pressurized air and liquid in one body. During our tests, water has been stored without loss, and batches were frozen whilst circulating and diffusing air through the liquid. The printing has been optimized with the slicer software and gcode editing, letting the fused filament 3D printer to build a diffuser membrane surrounded by air-tight walls. Detailed construction instructions are given, including piping and control board for operation. According to the functionality of the receptacle and the aeration system, the solutions have been found durable and low-cost. Disadvantages are the time invested in creating customized code, and certain limitations of the membrane itself.

A complex urban ecological investigation in a mid-sized Hungarian city - SITE assessment and monitoring of a liveable urban area, PART 1: Water quality measurement.

Urbanization and related environmental pollution have strong effects on stream systems by inducing short duration high-peak floods, raised levels of nutrients and contaminants, altered channel geomorphology, sediment dynamics, and reduced biotic richness. The main purpose of this current study is to detect stream contamination levels in a mid-sized Hungarian city by comparing the results of two separate years (2011, 2018). Discharge, channel geomorphology, and water quality parameters were measured, and load-based contamination was calculated for the city's main watercourse (Gaja Brook). The pH, CaCO3, texture, and heavy metal contents - Cd, Co, Cu, Ni, Pb, and Zn - were reanalysed in the sediment for both investigated years. For comparison, enrichment factors were used to determine sediment accumulation. As a complex parameter, biological water quality was also determined using BMWP and MMCP protocols in 2018. The results show that conductivity and the nutrient concentrations were higher, but the discharge values were lower in 2011 than in 2018. The nitrate load doubled both times in the brook between the first and the last sampling sites. The enrichment factors decreased or stagnated when the values of the two years were compared, but severe enrichment of Cd was detected in the middle of the city and south of the city. The aquatic macroinvertebrate fauna structure defined clean, but slightly impacted watercourses north and south of the city as well, but the abundance and presence of sensitive taxa differed at the sampling sites. Székesfehérvár has better than expected water quality, which can be attributed to the good ecological states of the hydromorphology and the streamside zone.

Influence of human impacts on trace metal accumulation in soils of two Hungarian cities.

Despite the advanced activity of urban soil research, comparison of available trace metal contents in the soil of settlements has not yet been well investigated. First aim of research was the comparison of human impacts on urban soils in two Hungarian cities with different structure and development. To detect the sources of contamination, Szombathely and Sopron cities were separated into urban, suburban and peri-urban areas. Altogether 192 topsoil samples were collected at 0-20 cm in order to measure the physicochemical properties of the soil. Instead of total element contents, plant-available trace metal concentrations - Cd, Co, Cu, Ni, Pb, Zn - were determined using ICP-OES method. Due to different geological conditions, urban soils of the investigated settlements had similar properties in the case of pH, CaCO3 and texture. In the case of plant available trace metals, limit excesses were found in urban and peri-urban areas mostly, but high values were recorded in the suburb. The amount of Cdavailable, Coavailable and Niavailable were negligible. Downtown area was the most contaminated in both cities, but extremes appeared in suburban areas. In Szombathely, Cuavailable values were <40 mg Cu/kg, but extremely high Cuavailable results were found in the peri-urban viticulture areas of Sopron (>90 mg Cu/kg). The samples taken alongside busy roads near the city centre were Pbavailable-contaminated due to traffic. The Pbavailable concentration decreased slightly towards the suburban areas of the cities. The Znavailable level exceeded 40 mg Zn/kg in soils taken from the watercourses of Szombathely. The highest trace metal pollution levels were recorded in soils of public parks of Sopron. Urban soils of Szombathely were more homogenized than urban soils of Sopron. Based on statistical analyses and comparison of the relations of urban, suburban, and peri-urban areas of Sopron to Szombathely, Szombathely's urban soils show more homogeneity.