This article reviews the different aspects of biochar as source and sink of organic and inorganic contaminants. Biochar can contain organic contaminants such as polycyclic aromatic hydrocarbons or heavy metals. As the distribution coefficients of the biochar especially for contaminants are high, the freely dissolved concentrations are low and with that also the bioavailability. The link between biochar's inherent contaminants and toxicity to soil meso- and macro-fauna remains unclear, with data being often contradictory and influenced by feedstock and pyrolysis conditions. The biochar's potential to remediate contaminated soils has mainly been addressed in lab studies, but rarely in the field. This far, results have been contradicting. Many studies reported successful immobilization of contaminants but some not. In summary, the ambivalent face of the biochar with regard to contaminants prevails. In future, long term field studies are needed to properly address the sustainability of biochar in this respect.

The utilization of bottom ashes from municipal solid waste incineration (MSWI) in road constructions might cause environmental problems due to the release of toxic metals. The present work is aimed at studying the suitability of soil as a treatment facility of metals leached out from bottom ashes. A laboratory experiment with three types of soil (forest soil, peat and mould soil), and with sand as a reference substrate, was performed to determine the binding capacity of each substrate towards heavy metals, such as Cu and Cr(VI). The results indicated that all the substrates were capable of removing on average 99,3 % of Cu from the solution, while only peat showed a high retention of Cr(VI) (96,2 %). The retention of Cr(VI) was directly proportional to the soil organic matter (SOM) content, while the retention of Cu had no correlation with the SOM of the substrates. A high retention of Cu shown by sand was due to its high content of pH which could favor the precipitation of Cu(OH)2. A synergetic effect of Cu on the retention of Cr(VI) by sand and mould was detected, i.e. increasing concentrations of Cu in the solution increased the retention of Cr. In all the other cases there was no statistically significant interaction between the retention of Cu and Cr(VI) by the analysed substrates.

This study analyses some characteristics of ancient construction and clarifies how they used renewable energy in their homes. This article analyzes ancient houses that were nature-oriented and used renewable energy. This study focuses on the structural system of ancient houses in Sistan. It dissects the structural elements of the old homes. The autopsy of the ancient house structure of Sistan shows the reader the techniques used in ancient architecture to provide energy. The research methods of this article are to examine the energy supply experiences of houses in the form of a case study of an old Sistan house to discover their energy-supplying techniques. This article uses the techniques used in Sistani houses with the application of modern house-building technologies, to develop a nature-oriented model. In fact, the model presented in this article is a modernized version of the ancient house of Sistan. This model gives a house completely friendly to nature and the environment and knowledge-oriented. The model contributes to housing programs addressing new requirements. Our proposed housing model and its general principles are replicable in other regions globally to use green energy sustainably.

The development of urbanization and the transformation of green lands into impermeable land increase temperature and create urban heat islands (UHIs). Our observations with remote sensing instruments of Landsat platforms show considerable changes in land use types in Beijing city with the shrinking of green lands, expansion of built envi-ronments, and a slight increase in the temperature during the recent four decades. Using remote sensing instruments of Landsat platforms and registered data from two meteorological stations in Beijing, this study finds the relationship between land surface temperature (LST) and the increasing conversion of cultivated lands into built-up areas. This article presents innovative research that shows the mutual correlation well and recommends revisions in the land use policies for better weather. The geographically weighted regression model (GWR) with a Gaussian weighting kernel function analyzes the impact of various urban land use types on the LST and the increase UHIs. In Beijing city, green lands show fewer standard deviations (SD) in the average temperatures equal to 0.109, while the industrial spaces exhibit a high SD equal to 0.212. The outcomes of this paper contribute to finding optimal land use policies everywhere in the world with the increasing urbanization through simulating its model for a more comfortable life.