Terrestrial eutrophication of building materials and buildings: An emerging topic in environmental studies

Changing climate intensifies downstream eutrophication by enhancing nitrogen availability from tropical forests

The contribution of diffuse nutrient exports from forests to downstream water bodies is significant owing to their extensive spatial distribution across watersheds. However, the intricacies of coupling mechanism between diffuse nutrient exports and meteorological factors driving downstream eutrophication remain poorly understood. Multiple methods involving field sampling, laboratory analysis, and model simulation were utilized to investigate the impact of diffuse nutrient exports from tropical forests on chlorophyll a concentration dynamic in the downstream reservoir. A strong positive correlation was observed between air temperature and chlorophyll a concentration, indicating the direct influence of climatic factors on microalgal biomass. The significant positive linear relationship was also observed between diffuse nitrate exports and chlorophyll a concentration, with a regression coefficient of 0.36 (P < 0.001), underscoring the role of nitrogen inputs in stimulating microalgal growth. The interplay between diffuse nitrate exports and meteorological factors was shown to regulate chlorophyll a concentration fluctuation. Additionally, the structural equation model revealed that increasing temperature and decreasing precipitation could elevate chlorophyll a concentration by enhancing nitrogen availability. Monte Carlo simulation results further revealed that temperature and precipitation were the most influential factors affecting chlorophyll a concentration during dry and rainy seasons, with sensitivity values of 0.94 and - 0.76, respectively. Notably, the eutrophication status was projected to deteriorate from light to moderate under diminishing precipitation conditions. These findings underscore the urgency of addressing eutrophication risks in reservoirs surrounded by tropical forests and the implementation of effective nitrate mitigation strategies is imperative, which offers theoretical guidance for the management of eutrophic water restoration within tropical rainforest regions under changing climate conditions.

A comparative approach to evaluate the toxicity of building materials through life cycle assessment

BACKGROUND

This paper addresses the lack of research that compares the toxicity of commonly used construction materials. The toxicity of construction materials has received less attention, despite its importance within the Life Cycle Assessment methodology. All aspects, including toxicity, need to be analysed throughout the life cycle of the material to understand its true behaviour.

AIM

The purpose of this study is to propose a methodology to compare the toxicity of different construction materials and highlight the need to consider toxicity criteria in the selection of materials during the design phase. The study seeks to fill the gap in the existing literature by providing information on the comparative toxicity of the most common building materials.

METHODOLOGY

The study follows Life Cycle Assessment methodology as established by the ISO 14040:2006 and ISO 14044:2006 standards. For this study, statistics were consulted to identify the most used materials in the construction sector; then, from this group of materials, those available in the Ecoinvent 3.7.1 database were selected. For comparison, these materials were categorised into material families and a functional unit was established to compare them. Finally, all materials were compared with each other, using 1 kg as the functional unit.

RESULTS

When we conduct a comparative analysis of various materials and categorise them into groups, it becomes readily apparent which materials demonstrate a less favourable performance with respect to their toxic properties. This approach allows us to discern and pinpoint those materials that present a more concerning level of toxicity relative to others, facilitating informed decision-making in terms of construction material selection and design.

CONCLUSIONS

By comparing all materials with each other using 1 kg as the functional unit, we can conclude that some materials have a greater impact than others, both in absolute and relative terms, for example, steel and polyurethane foam.

Biodiversity burdens in Spanish conventional and low-impact single-family homes

Biodiversity loss caused by housing is not a well-defined sector of environmental impact. This research quantifies effects on biodiversity of an average Spanish Single-Family House (SFH) with 180 m2 of built surface. The current Spanish SFH stock GWP amounts to 1.16 Gt CO2eq in a 50-year life cycle, 40 % of which is embodied in the building materials and the 60 % are emissions due to the use of the building. This stock also impacts with 10.2 Gt 1,4-DCB the land, water and human health. SFHs also drive 6052 species extinct in a 50 year life cycle, and account for 3.03 M years of life lost due to premature death or lived with a disability. Divided by the 16 M people living in Spanish SFHs, each one lost 0.19 years of their lives (68.1 days) due to their home's impacts on human health. The article compares a reference conventional building against three low-impact cases, to understand how different building techniques and materials influence environmental outcomes that keep biodiversity loss the lowest possible. Scenarios include a standard brick and concrete house as Scenario 0 (SC0, Base), a timber Passivhaus as Scenario 1 (SC1), a straw-bale house with renewable energies as Scenario 2 (SC2), and an earth bioclimatic house as Scenario 3 (SC3). An initial Global Warming Potential (GWP) analysis was performed to relate previous building Life Cycle Assessment (LCA) studies with biodiversity metrics. Three main biodiversity metrics; ecotoxicity (as midpoint indicator), biodiversity loss and damage to human health (both as endpoint indicators) have been considered. Compared to SC0 with 1292 kgCO2-eq·m-2 (516 embodied) of GWP, we found that SC1 emitted -47.0 % of that, SC2-41.4 % and SC3-80.9 %. Concerning ecotoxicity, where SC0 has 11,399 kg 1,4 DCB, the results are -27.9 % in SC1, -19.2 % in SC2, and -45.6 % in SC3. Regarding biodiversity loss, where SC0 has 7.54 E-06 species.yr·m-2, the impacts are -30.9 % in SC1, -32.6 % in SC2, and -58.6 % in SC3. Human health damage in SC0 being 3.37 E-03 DALY, has been reduced in the timber home (SC1) is -44.2 %, of the Straw SFH (SC2) -39.2 %, and of the earth house (SC3) -67.1 %. This article shows that with current existing technological solutions GWP could be reduced in -80.9 %, ecotoxicity in -45.6 %, biodiversity loss in -58.6 % and human health in -67.1 %. Spanish Single-Family Houses built in timber, earth or straw-bale are real alternatives to current cement traditional building.

Characterisation of a low methane emission rice cultivar suitable for cultivation in high latitude light and temperature conditions

Rice cultivation on paddy soil is commonly associated with emissions of methane, a greenhouse gas, but rice varieties may differ in their actual level of emissions. This study analysed methane emissions associated with 22 distinct rice genotypes, using gas chromatography, and identified the cultivar Heijing 5 from northern China as a potential low-methane rice variety. To confirm this and to examine whether Heijing 5 can perform similarly at higher latitudes, Heijing 5 was cultivated in field trials in China (lat. 32° N) and Sweden (lat. 59° N) where (i) methane emissions were measured, (ii) methanogen abundance in the rhizosphere was determined using quantitative PCR, and (iii) the concentrations of nutrients in water and of heavy metals in rice grain and paddy soil were analysed. The results demonstrated that the low-methane rice cultivar Heijing 5 can successfully complete an entire growth period at high-latitude locations such as central Sweden. Massively parallel sequencing of mRNAs identified candidate genes involved in day length and cold acclimatisation. Cultivation of Heijing 5 in central Sweden was also associated with relatively low heavy metal accumulation in rice grains and lowered nutrient losses to neighbouring water bodies.

Phosphate removal using dolomite modified with ultrasound: mathematical and experimental analysis

We studied the dolomite modified using an ultrasound bath and its application in phosphate removal. The modification was applied to improve the physicochemical properties of the dolomite and then to enhance its suitability as an adsorbent solid. The settings for analyzing the adsorbent modification were bath temperature and sonication time. The modified dolomite was characterized by electron microscopy, N₂ adsorption/desorption, pore size, and X-ray diffraction. To grasp the pollutant's adsorption mechanism more precisely, we used experimental research and mathematical model analysis. Design of Experiments was conducted to determine the ideal circumstances. In addition, the Bayesian method of Markov Chain Monte Carlo was used to estimate the isotherm and kinetic model parameters. A thermodynamic study was done to investigate the adsorption mechanism. Results show that the surface area of the modified dolomite was greater, enhancing its adsorption properties. To remove more than 90% of the phosphate, the optimal operational parameters for the adsorption were pH 9, 1.77 g of adsorbent mass, and 55 minutes of contact time. The pseudo-first-order, Redlich-Peterson and Sips models presented a good fit to the experimental data. Thermodynamics suggested a spontaneous and endothermic process. The mechanism suggested that physisorption and chemisorption could be involved in phosphate removal.

Portable determinations for legislated dissolved nitrogen forms in several environmental water samples as a study case

In this work, we have studied the main species involved in determining total dissolved nitrogen (TDN) in water samples for accommodating a variety of quantitation methodologies to portable instruments and with the goal to achieve in situ analysis. The rise of water eutrophication is becoming an ecological problem in the world and TDN contributes markedly to this. Traditionally the several forms of DN are measured in the laboratory using conventional instrumentation from grab samples, but their analysis in place and in real time is a current demand. Inorganic nitrogen: NO₃^-, NO₂^- and NH₄⁺, and organic nitrogen, such as amino nitrogen were tested here. For nitrate that presents native UV absorption suitable for direct water analysis, a portable optical fiber probe was compared with benchtop equipment and an in place analyzer. For nitrate, nitrite and ammonium, in situ solid devices that deliver reagents needed were tested and water color was measured by a smartphone coupled with a miniaturized optical fiber spectrometer and a miniaturized spectrometer or from images obtained and their RGB components. Amino nitrogen of some aromatic aminoacids with native fluorescence was followed by a portable optical fiber probe. Organic amino nitrogen and ammonium were determined by a portable luminometer and luminol supported in a measurement tube. Moreover, a portable miniaturized liquid chromatograph was shown suitable for monitoring priority nitrogen environmental pollutants. All options provided suitable results in comparison with lab estimations and were useful for evaluating if the legislation is fulfilled for the variety of tested waters. A discussion about the several portable options proposed for in place analysis, in function of the legislated determinations needed for each type of water was carried out.

Mapping Blue and Red Color-Coated Steel Sheet Roof Buildings over China Using Sentinel-2A/B MSIL2A Images

Accurate and efficiently updated information on color-coated steel sheet (CCSS) roof materials in urban areas is of great significance for understanding the potential impact, challenges, and issues of these materials on urban sustainable development, human health, and the environment. Thanks to the development of Earth observation technologies, remote sensing (RS) provides abundant data to identify and map CCSS materials with different colors in urban areas. However, existing studies are still quite challenging with regards to the data collection and processing costs, particularly in wide geographical areas. Combining free access high-resolution RS data and a cloud computing platform, i.e., Sentinel-2A/B data sets and Google Earth Engine (GEE), this study aims at CCSS material identification and mapping. Specifically, six novel spectral indexes that use Sentinel-2A/B MSIL2A data are proposed for blue and red CCSS material identification, namely the normalized difference blue building index (NDBBI), the normalized difference red building index NDRBI, the enhanced blue building index (EBBI), the enhanced red building index (ERBI), the logical blue building index (LBBI) and the logical red building index (LRBI). These indexes are qualitatively and quantitatively evaluated on a very large number of urban sites all over the P.R. China and compared with the state-of-the-art redness and blueness indexes (RI and BI, respectively). The results demonstrate that the proposed indexes, specifically the LRBI and LBBI, are highly effective in visual evaluation, clearly detecting and discriminating blue and red CCSS covers from other urban materials. Results show that urban areas from the northern parts of P.R. China have larger proportions of blue and red CCSS materials, and areas of blue and red CCSS material buildings are positively correlated with population and urban size at the provincial level across China.

Comparative environmental evaluation of recycled aggregates from construction and demolition wastes in Italy

Ensure sustainable consumption and production patterns requires urgent actions to combat climate change and its impacts as established by Sustainable Development Goals (SDGs). In this context, this study demonstrates the feasibility to produce structural concrete using recycled aggregates from construction and demolition waste in Italy. More specifically, the present research aims to analyze the environmental impacts caused by five mixtures of concrete, with similar mechanical properties and workability, but with a different amount of recycled coarse aggregate and natural coarse aggregate (0% - 30% - 50% - 70% - 100%). Fixed plant and a mobile plant treatments are investigated as two different modes of production of recycled aggregates. Life Cycle Assessment (LCA) methodology is applied to achieve this goal. The main results demonstrate that mixtures formed by recycled coarse aggregates have a better environmental impacts than the only one formed exclusively by natural coarse aggregates and results improve when the amount of recycled coarse aggregate is higher.

The influence of marine environment on the conservation state of Built Heritage: An overview study

Marine aerosol is a chemical complex system formed by inorganic salts and organic matter, together with airborne particulate matter from the surrounding environment. The primary particles transported in the marine aerosol can experiment different chemical reactions in the atmosphere, promoting the so-called Secondary Marine Aerosol particles. These kinds of particles (nitrates, sulfates, chlorides etc.), together with the natural crustal or mineral particles and the metallic airborne particulate matter emitted by anthropogenic sources (road traffic, industry, etc.) form clusters which then can be deposited on building materials from a specific construction following dry deposition processes. Apart from that, the acid aerosols (e.g. CO₂, SO₂, NO_X, etc.) present in urban-industrial environments, coming also from anthropogenic sources, can be deposited in the buildings following dry or a wet deposition mechanisms. The interactions of these natural and anthropogenic stressors with building materials can promote different kind of pathologies. In this overview, the negative influence of different marine environments (direct or diffuse influence), with or without the influence of an urban-industrial area (direct or diffuse), on the conservation state of historical constructions including a wide variety of building materials (sandstones, limestones, artificial stones, bricks, plasters, cementitious materials, etc.) is presented.

Combined use of calcium nitrate, zeolite, and anion exchange resin for controlling phosphorus and nitrogen release from sediment and for overcoming disadvantage of calcium nitrate addition technology

Ca(NO₃)₂ addition has proved to have a high potential to immobilize internal phosphorus (P) in sediments; however, it cannot effectively stop the release of ammonium-nitrogen (NH₄⁺-N) from sediments into overlying waters (OL-waters). Additionally, the addition of Ca(NO₃)₂ alone has high risk of nitrate-nitrogen (NO₃^--N) releasing into OL-waters. To overcome the shortcoming of the Ca(NO₃)₂ addition method, we reported an integrated method, i.e., a combined method based on Ca(NO₃)₂ injection, zeolite capping, and anion exchange resin (AERN)-contained floating system suspending (Ca(NO₃)₂/zeolite/AERN). The effectiveness and mechanism of the Ca(NO₃)₂/zeolite/AERN method for simultaneously controlling the release of soluble reactive P (SRP) and NH₄⁺-N were investigated, and the NO₃^--N releasing risk of this method was evaluated. It was found that the joint use of Ca(NO₃)₂ injection, zeolite capping, and AERN-contained floating system suspending not only could effectively suppress the release of SRP and NH₄⁺-N from sediments into OL-waters simultaneously, but also had much less risk of NO₃^--N releasing into OL-waters as compared to the single Ca(NO₃)₂ injection method and the combined Ca(NO₃)₂/zeolite method. The inhibition of the reductive dissolution of the P-bound Fe(III) oxides/hydroxides by the presence of nitrate and the adsorption of ammonium on the zeolite played very important roles in the interception of SRP and NH₄⁺-N releasing into OL-waters by the Ca(NO₃)₂/zeolite/AERN method. After the sediment remediation using the Ca(NO₃)₂/zeolite/AERN approach, the increase in the content of residual P in the sediment layer of 0-50 mm, the decrease of mobile P in the sediment layer of 0-10 mm, and the increased NH₄⁺-N adsorption capacity for the sediment layer of 0-10 mm would be conductive to the interception of SRP and NH₄⁺-N liberation in the long run. Results of this research suggest a promising application potential of the Ca(NO₃)₂/zeolite/AERN method in the simultaneous control of the release of SRP and NH₄⁺-N from sediments.

Novel Composite Materials for Lake Restoration: A New Approach Impacting on Ecology and Circular Economy

The purpose of this study is to promote a new way of application composite materials to restore eutrophic waters. A new sustainable way of application is based on the “teabag” method, in which materials were placed in water-permeable bags and immersed in the water column in order to sorb phosphate—one of the main contributory element for the eutrophication problem. Particularly, the two composites materials of Phoslock™ (lanthanum-modified bentonite, LMB) and Bephos™ (Fe-modified bentonite, f-MB) were tested and bench-scale batch experiments were employed to investigate their sorption efficiency in the forms of slurry and teabag. The adsorption kinetics and the relevant adsorption isotherms were deployed, while the effect of the materials on turbidity and their aging were also investigated. Experimental results showed that Phoslock™ and Bephos™ (as teabag), being applied at initial concentration range: 0.05–5 mg/L, they sustained a maximum adsorption capacity of 7.80 mg/g and 25.1 mg/g, respectively, which are considered sufficient rates for P concentrations reported at natural aquatic ecosystems. At the same time this new method did not cause turbidity in the water column, since the material was not released into the water, thus, preventing potential harmful consequences for the living organisms. Moreover, the “teabag” method prevents the material to cover the lake bottom, avoiding the phenomenon of smothering of benthos. Βy teabag method, the materials can be collected for further applicability as soil improver or crops fertilizer. Finally, it was argued that the possibility to recycle LMB and f-MB materials for agricultural use is of paramount importance, sustaining also positive impacts on sustainable ecology and on the routes of circular economy (CE).