We studied short-term changes in macrozoobenthos in a 20m deep borrow pit. A boxcorer was used to sample macrobenthic infauna and a bottom sledge was used to sample macrobenthic epifauna. Sediment characteristics were determined from the boxcore samples, bed shear stress and near-bed salinity were estimated with a hydrodynamic model. Two years after the cessation of sand extraction, macrozoobenthic biomass increased fivefold in the deepest areas. Species composition changed significantly and white furrow shell (Abra alba) became abundant. Several sediment characteristics also changed significantly in the deepest parts. Macrozoobenthic species composition and biomass significantly correlated with time after cessation of sand extraction, sediment and hydrographical characteristics. Ecosystem-based landscaped sand bars were found to be effective in influencing sediment characteristics and macrozoobenthic assemblage. Significant changes in epifauna occurred in deepest parts in 2012 which coincided with the highest sedimentation rate. We recommend continuing monitoring to investigate medium and long-term impacts.

Rapid migration to cities and the increasing demand for housing negatively affect living areas. Furthermore, uncontrolled population growth, industrialization, urbanization, narrowing of urban areas, and expansion of cities cause physical boundaries. Urbanization growth and the cold climate restrict pedestrian mobility in the city. Therefore, hourly microclimate data of the city center streets were collected 1.5 m above ground level in the winter period of 2019–2020. Then, different landscape design scenarios on pedestrian roads were investigated extensively using the ENVI-met V.4.4.2 winter model to determine the outdoor thermal comfort level. The RayMan model was utilized to generate the sky view factor (SVF) and analyze the mean values of the microclimate data. The proposed landscape design scenarios were as follows; (1) hard-covered street, (2) complete street coverage with a canopy, (3) street coverage with a semi-canopy, (4) sage of a combination of different plant species (30% deciduous, 30% coniferous, 30% bush), and (5) usage of ornamental pools in streets. The time period when pedestrians used the outdoor space was taken into consideration in evaluating and interpreting the analysis results. The findings of this study generally indicated that the semi-open canopy design provided roads with high thermal comfort such that people can walk and cycle in winter time. In conclusion, the thermal comfort condition of a street design, which is important for achieving sustainable urbanization, can be changed by making appropriate plan decisions. The findings of this study will help improve the outdoor thermal comfort in the first stage of urban planning and landscape street design for more livable and effective cities. This study emphasizes that a multidisciplinary team should work together to establish a healthy, sustainable, and livable urbanized area with thermal comfort in the streets.

The use of treated grey water (GW) for home gardens, peri-urban agriculture and landscaping is becoming popular in many water stressed countries such as Oman. This study aims to investigate the treatment efficacy, health and chemical concerns, cost-benefits and maintenance protocol of a GW treatment system as well as the effect of irrigation with GW on crop yield. Therefore, a decentralized homemade GW treatment system was installed in a newly constructed house in Muscat, Oman and studied over a 2-year period. The treated GW was found to be suitable for irrigation as per Omani standards. GW when mixed with kitchen effluent substituted the use of nutrient supplements for plants and did not show any harmful chemical or biological contamination. The capital cost of the system was around US $980, and the annual operating cost was US $78 with annual income and savings from the system being around US $572 indicating a payback period of nearly 2 years. It was found that the system required simple but regular maintenance particularly cleaning of the top layer of the filter. It can be concluded from this study that such a GW system should be technically, economically and environmentally feasible in Oman. Also, wider acceptance by the general public to the idea of GW reuse will help in mitigating the water shortage problem of the country to some extent.

In the present study, a two-tiered research method was adopted. In the first stage, a literature review was conducted to determine the associations that landscape colors evoke in individuals and each association was converted into a statement for each color. The developed 5-point Likert-type scale was submitted for expert opinion (N = 200), and factor analysis was conducted on the findings to determine correlated sub-factors and categorized in the same factor. Thus, three factor groups were determined. Thus, the survey form that will be used in the second study stage was finalized. The factor analysis was also conducted to reduce the number of statements in the scale. Furthermore, 102 statements with a factor load of below 0.30 were excluded. Thus, the final scale included 34 associations in 3 dimensions. In the second stage, the final 5-point Likert-type survey form was applied to the expert group (N = 200) and the participants (N = 200) to determine the agreement of these two groups with the associations. Also, the differences between the agreement levels of the two groups with the associations and the differences between the associations were determined. The statistical analyses revealed that there was a difference between the mean association scores of the participant and the expert groups in 3 factor groups at 0.05 significance level (sig. 0.000, F = 34.432). The direction and size of the correlations between the factors were determined with the correlation analysis, multiple regression analysis was conducted to determine the effect of the factors on others, and it was determined that there was a positive significant correlation between 1st factor and agreement and a negative significant correlation between the 2nd and 3rd factor groups and agreement. The order of the factors that explained the variation in agreement was the 1st factor (ß = .332; p = 0.000), the 2nd factor (ß = − .274; p = 0.000), and the 3rd factor (ß = − .157; p = 0.001), respectively.

Under the climate change scenario, the negative impacts of urban heat island (UHI) will exacerbate due to unsustainable urban planning and human activities. Thermal comfort has close relationships with UHI in urban areas. This paper is based on the studies of urban heat island, thermal comfort, microclimate, and urban planning in cities in the recent decade, combined with a method of research into design. The key topics include vegetation and water conditions, the albedo of materials, and urban morphology. By the comparative case studies in landscape projects, the results further reveal that the density of tree canopies, the natural structure and density of ground cover, the form of water features, the color and texture of materials, and the scale of shading structures have different cooling effect and performance in outdoor thermal comfort improvement with specific features in the landscape design. It is also found that there are some external conditions that can influence design determinations in real practices. The purpose of this study is to provide theoretical research methods and evaluation of thermal comfort landscape design elements and to provide guidance for future sustainable city research and landscape design.

The use of plants for ecological remediation is an important method of controlling heavy metals in polluted land. Cotinus coggygria is a landscape plant that is used extensively in landscaping and afforestation. In this study, the cadmium tolerance level of C. coggygria was evaluated using electrical impedance spectroscopy (EIS) to lay a theoretical foundation for broad applications of this species in Cd-polluted areas and provide theoretical support to broaden the application range of the EIS technique. Two-year-old potted seedlings of C. coggygria were placed in a greenhouse to analyse the changes in the growth, water content and EIS parameters of the roots following treatment with different Cd concentrations (50, 100, 200, 500, 1000 and 1500 mg kg⁻¹), and soil without added Cd was used as the control. The roots grew well following Cd treatments of 50 and 100 mg kg⁻¹. The Cd contents increased with the increase in Cd concentration in the soil. However, the lowest root Cd content was found at 4 months of treatment. The extracellular resistance rₑ and the intracellular resistance rᵢ increased first overall and then decreased with the increasing Cd concentration, and both parameters increased with a longer treatment duration. The water content had a significant negative correlation with the Cd content (P < 0.01) and the rₑ (P < 0.05). C. coggygria could tolerate a soil Cd concentration of 100 mg kg⁻¹. There was a turning point in the growth, water content and EIS parameters of the C. coggygria roots when the soil Cd concentration reached 200 mg kg⁻¹. The root water content and rₑ could reflect the level of Cd tolerance in C. coggygria.

Disused creosote-treated railway ties are reused in France and many other countries and, in particular, for landscaping and other residential uses. Given the lack of data on the environmental fate of creosote-derived compounds released from used railway ties, a survey of different environmental media (i.e. soil, sediment, surface water, plants and outdoor air) was carried out at six sites located in France where old creosote-treated railway ties are stored or reused for different purposes. Maximum total polycyclic aromatic hydrocarbon (PAH) concentrations measured in soils ranged from 2 to 140 mg/kg dry weight. PAH impacts were limited both vertically and horizontally to several centimetres from the railway ties. At two sites, PAH levels in plants (up to 140 μg/kg fresh weight) appeared correlated to the levels measured in soils, suggesting a transfer from soils to the plants. PAHs in sediment were measured at concentrations of up to 280 mg/kg dry weight. As observed in soil, PAH concentrations decreased rapidly further away from the railway ties. Principal component analysis and hierarchical clustering on principal components indicate that PAHs detected in soils and sediments originated from unweathered to severely weathered creosote and could be strongly influenced by urban background. Results on outdoor air measurements show a degradation of air quality above old and fresh railway tie storage areas at a railway station and to a lesser extent in their vicinity. However, this degradation was low to moderate when compared to French regulatory values, ambient background levels reported in France, as well as health-based air comparison values.