The central part of the tin ore deposit Ehrenfriedersdorf/Erzgebirge, which was exploited from the 13th century to 1990, was flooded from 1994 to 1996. Since that time mine waters have flown through the gallery “Tiefer Sauberger Stolln” to the creek Wilisch in the Elbe river catchment area. The water at the mine portal shows high concentrations of arsenic and heavy metals. The average arsenic concentration is about 0.5 mg/L. Approximately two thirds of arsenic are transported dissolved. Where the mine water ascends from deeper levels, arsenic concentrations of about 0.4 mg/L were found. Here arsenic occurs predominantly particular. The mining gallery “Tiefer Sauberger Stolln” provides the unique opportunity of subsurface sampling for the identification of the arsenic sources under different hydrological conditions (normal and high water level). The sources of dissolved arsenic in the gallery part between the raise and the portal were determined and analyzed. Between these two monitoring points, many inflows of infiltration water were detected. The concentration of As in the infiltration water reaches up to 1.8 mg/L, which varies depending on the location in the gallery and the hydrological situation. The first part of the gallery was straightened, heightened and partly concreted with modern mining technique. The arsenic concentrations can decrease owing to high precipitation rates and snow melt events. The last part of the gallery was preserved due to low coverage. Here the arsenic concentrations in the infiltration waters increase with the surface water inflow. At a normal water level, 1 kg arsenic per day leaves the raise and 2.1 kg the gallery portal, which means that 50 % of the arsenic load comes from the infiltration water. At a high water level, 2.5 kg arsenic per day are transported through the raise and 8.2 kg per day through the gallery portal, which means that about 70 % of the arsenic load comes from infiltration water. The area of Ehrenfriedersdorf is characterized by a superposition of anthropogenic soil pollution over the geogenic inventory. There is a close connection between ancient soil contaminations by high amounts of water‐soluble arsenic compounds, e.g. arsenic trioxide formed by roasting the ores during ancient tin smelting, and high concentrations of dissolved arsenic in the infiltration water. The contamination of surface water and river sediments by arsenic is originating from an anthropogenic pollution of soils by ancient tailings via infiltration of water rich in arsenic into the mine gallery.

Rapid population growth necessitates modifications of urban form, especially in city centers. Consequently, the correlation of the outdoor environment with the occupant’s behavior has profoundly changed. In this study, the authors describe a method, that allows for the estimation of the impact of passive green technologies on the microclimate of historic urban structures, taking into account the city-specific conditions. The Envi-met application, which is widely applied in urban climatology, was used to create the atmospheric processes simulation. Passive scenarios such as green roofs, living facades, and high greenery for chosen periods—warm conditions and the hottest day—were considered. It enabled an assessment of microclimatic outdoor conditions at the pedestrian (1.4 m) and living level (5 m). The results suggested that the highest temperature reduction was related to the tree scenarios (0.09 °C at 1.4 m and 0.18 °C at 5 m height for warm a period; 1.23 °C at 1.4 m and 1.31 °C at 5 m height for the hottest day). The thermal comfort was calculated through the usage of simulated output data. In our investigation, the maximum change in PET was 1.51 °C (for the warm period) and 5.41 °C (during the hottest day of the year). The findings have valuable implications for the design of the city’s structure.

No abstract

The implementation of adaptation strategies has become an essential activity of spatial planning departments. Passive technologies related to the introduction of natural components in the form of vegetation are used, especially in urban development plans, to mitigate the effects of climate change and thus improve the quality of citizen life. Nature-Based Solutions are of particular importance in the areas of strict city centers, where historical building structures are subject to legal protection. In this study, the authors tested the influence of high greenery on the microclimatic conditions in the areas of typical street canyons (east–west and north–south orientations). Authors included the established greenery strategy by the City Planning Department. To estimate the impact of the assumed scenarios, a CFD tool was used—the ENVI-met application, which is commonly used in the field of urban microclimatology. Studies have shown that the introduction of 10% of green area contributed to a maximum air temperature reduction of 0.80 °C (17:00) in an east–west-oriented canyon, 0.49 °C (10:00) in a north–south canyon. The scenarios, assumed by the City Planning Department, related to the introduction of a greater amount of greenery turned out to be a less effective solution. The impact of greenery on the thermal comfort felt by humans was also determined. The reduction in the PET index was a maximum of 10.80 °C (14:00) in an east–west canyon; 6.66 °C (14:00) in a canyon area with a north–south orientation. This research might constitute the foundations to a re-evaluation of the urban development plans. The outcomes can lead to taking alternative direction of city layout transformations.