Lead (Pb) is a non-threshold toxin capable of inducing toxic effects at any blood level but availability of soil screening criteria for assessing potential health risks is limited. The oral bioaccessibility of Pb in 163 soil samples was attributed to sources through solubility estimation and domain identification. Samples were extracted following the Unified BARGE Method. Urban, mineralisation, peat and granite domains accounted for elevated Pb concentrations compared to rural samples. High Pb solubility explained moderate-high gastric (G) bioaccessible fractions throughout the study area. Higher maximum G concentrations were measured in urban (97.6 mg kg−1) and mineralisation (199.8 mg kg−1) domains. Higher average G concentrations occurred in mineralisation (36.4 mg kg−1) and granite (36.0 mg kg−1) domains. Findings suggest diffuse anthropogenic and widespread geogenic contamination could be capable of presenting health risks, having implications for land management decisions in jurisdictions where guidance advises these forms of pollution should not be regarded as contaminated land.

Submerged man-made structures present novel habitat for marine organisms and often host communities that differ from those on natural substrates. Although many factors are known to contribute to these differences, few studies have directly examined the influence of substrate material on organism settlement. We quantified larval substrate preferences of two species of ascidians, Ciona intestinalis (cryptogenic, formerly C. intestinalis type B) and Botrylloides violaceus (non-native), on commonly occurring natural (granite) and man-made (concrete, high-density polyethylene, PVC) marine materials in laboratory trials. Larvae exhibited species-specific settlement preferences, but generally settled more often than expected by chance on concrete and HDPE. Variation in settlement between materials may reflect preferences for rougher substrates, or may result from the influence of leached chemicals on ascidian settlement. These findings indicate that an experimental plate material can influence larval behavior and may help us understand how substrate features may contribute to differences in settlement in the field.

Strong differences have been observed between the assemblages on artificial reefs and on natural hard-bottom habitats worldwide, but little is known about the mechanisms that cause contrasting biodiversity patterns. We examined the influence of spatial attributes in relation to both biogenic and topographic microhabitats, in the distribution and composition of intertidal species on both artificial and natural reefs. We found higher small-scale spatial heterogeneity on the natural reef compared with the study breakwater. Species richness and diversity were associated with a higher availability of crevices, rock pools and mussels in natural habitats. Spatial distribution of certain grazers corresponded well with the spatial structure of microhabitats. In contrast, the lack of microhabitats on the breakwater resulted in the absence of several grazers reflected in lower species richness. Biogenic and topographic microhabitats can have interactive effects providing niche opportunities for multiple species, explaining differences in species diversity between artificial versus natural reefs.

Marine urbanisation often results in the proliferation of artificial coastal defences and heavy sedimentation, adversely impacting coral reef systems in tropical coastal cities. Knowledge of how motile organisms, such as reef fish, respond to novel human-made habitats and high sedimentation is limited. Here, we examine the role of sloping granite seawalls in supporting reef fishes that utilise the epilithic algal matrix (EAM) as a food resource. We surveyed fish assemblages and feeding activities on seawalls and reef flats, and conducted a field experiment to examine the effects of sediment on EAM feeding rates. Seawalls and reef flats supported distinct fish assemblage composition with significantly greater feeding activity on seawalls. However, reduced feeding activity on EAM with elevated sediment loads suggests that urban sedimentation may limit the utility of this novel feeding ground for nearshore communities. These findings illustrate the complexities and interactive effects of anthropogenic changes driven by coastal urbanisation.

The use of the ornamental stone wastes, such as the originated from granite or marble, has been the subject of technological studies that evaluated its application in ceramic and cement materials; however, some complementary assessments, such as its life cycle assessment, are still not well explored in the literature. Therefore, the objective of this study was to discuss the main environmental impacts related to the manufacture of ceramic specimens, comparing conventional production versus the production of specimens incorporated with ornamental stone wastes. For this, the life cycle assessment was conducted in accordance with ISO 14.040 and 14.044. For this research, the ornamental stone wastes from the municipality of Cachoeiro do Itapemirim–ES and clay from the municipality of Campos dos Goytacazes–RJ were used. The system was modeled, using the SimaPro 9.0 software and the Ecoinvent database 3.3, for the life cycle assessment of the ceramic specimens and the potentiality regarding the use of ornamental stone wastes in ceramic materials using alternative input energy for burning, contributing to the effectiveness of the solid wastes reuse by the ceramic industry. The evaluation identified that the ornamental stone wastes incorporated into the ceramic specimens had significant potential in reducing environmental impacts and that the alternative input energy in burning stage makes them even more relevant. The study points out as the main result, the reduction of 35.74% of the impacts related to the category of the emission of greenhouse gases, and scarcity of mineral resources, 14.83% reduction, when compared to specimens to conventional brick production and alternative brick production, which emphasizes that the ceramic materials with wastes contribute to the mitigation of impacts.

Mass transport and residence time of saline water from road salt applications in soil columns composed of Toyoura sand and weathered granite sand were investigated by simulations and in laboratory experiments. Both are sands found in Japan, especially the weathered granite sand. The Toyoura sand has a fairly uniform particle size of 0.1 to 0.4 mm diameter, and a saturated hydraulic conductivity Kₛ = 0.0296 cm/s, while the weathered granite sand used consisted of 13% fine materials (silt and clay) and 87% coarse materials (sand and gravel) with a saturated hydraulic conductivity Kₛ = 0.00393 cm/s. A model was developed to simulate rinsing of brine from a soil column. Assuming a steady, homogeneous flow induced by rainwater infiltration into the soil column, the model was found to match the experimental results for Toyoura sand very well. The normalized salt concentration in the effluent from the 40 cm tall soil column remained constant until about t = 500 s; the concentration then decreased with time quickly and, finally, approached zero. For the weathered granite sand, however, the salt concentrations in the effluent simulated by the model with assumption of homogeneous flow are inconsistent with the experimental data collected. A substantial delay occurs in mass transport of salt from the column, which is different from the Toyoura sand. The delay is attributed to shifts in “active” and “inactive pores” created in the soil due to fine particles such as silt and clay. The proportion of “active pores” and “inactive pores” is not constant but variable with time due to physical and/or electrochemical processes such as pore-size distributions and salt depletion in the soil. A modified model presented, using a time-variable active pore parameter k(t), can reproduce the experimental results for salt mass left in the soil better.

In tropical countries like Colombia, a large variety of available aquatic plants have yet to be investigated for phytodepuration processes. The aim of this study was to assess the effect of Cyper-us ligularis and Echinocloa colona¸ two local plants of Colombian Caribbean region, on removal of dissolved organic matter (COD) and nutrients (N-NH₄⁺, N-NO₃⁻ and P-PO₄⁻³) from domestic wastewater. Experiments were conducted in replicate pilot-scale Horizontal Subsurface Flow Constructed Wetlands (HSSF CWs) (0.66 m²). Four wetland treatment units were installed in parallel. Two were planted with C. ligularis and the other two remained with E. colona. The experimental system was connected to a 0.76-m³ primary sedimentation tank that fed experimental wetland treatment units. Wetlands were filled with granite gravel (~8 mm and 0.4 of porosity). During a period of 4 months, each treatment unit received a continuous loading at the rate of 42 L day⁻¹ and a hydraulic retention time of 2.3 days approximately. Wastewater samples from influent and effluents were collected three times each week in order to monitor temporal/spatial changes in removals efficiencies of COD, N-NH₄⁺, N-NO₃⁻, and P-PO₄⁻³. Results showed that removals of COD, N-NH₄⁺, and N-NO₃⁻ were not significantly different between treatments (p > 0.05). Nevertheless, P-PO₄⁻³ removal for E. colona was significantly higher than C. ligularis (p < 0.05), showing that this plant can assimilate important amounts of P. Further investigations must be conducted to evaluate the potential of native aquatic macrophytes for phytodepuration.

To elucidate the influence of airborne materials on the ecosystem of Japan’s Yakushima Island, we determined the elemental compositions and Sr and Nd isotope ratios in streamwater, soils, vegetation, and rocks. Streamwater had high Na and Cl contents, low Ca and HCO₃ contents, and Na/Cl and Mg/Cl ratios close to those of seawater, but it had low pH (5.4 to 7.1), a higher Ca/Cl ratio than seawater, and distinct ⁸⁷Sr/⁸⁶Sr ratios that depended on the bedrock type. The proportions of rain-derived cations in streamwater, estimated by assuming that Cl was derived from sea salt aerosols, averaged 81 % for Na, 83 % for Mg, 36 % for K, 32 % for Ca, and 33 % for Sr. The Sr value was comparable to the 28 % estimated by comparing Sr isotope ratios between rain and granite bedrock. The soils are depleted in Ca, Na, P, and Sr compared with the parent materials. At Yotsuse in the northwestern side, plants and the soil pool have ⁸⁷Sr/⁸⁶Sr ratios similar to that of rainwater with a high sea salt component. In contrast, the Sr and Nd isotope ratios of soil minerals in the A and B horizons approach those of silicate minerals in northern China’s loess soils. The soil Ca and P depletion results largely from chemical weathering of plagioclase and of small amounts of apatite and calcite in granitic rocks. This suggests that Yakushima’s ecosystem is affected by large amounts of acidic precipitation with a high sea salt component, which leaches Ca and its proxy (Sr) from bedrock into streams, and by Asian dust-derived apatite, which is an important source of P in base cation-depleted soils.

Biochar has a great potential to sustainably improve the performance of bio-engineered slope due to its ability to retain water and to supply nutrients. Existing studies mainly focus on hydrological properties of biochar-amended soil. However, the effects of biochar on shear strength of soil are not well studied. This study aims to assess the shearing behaviour of biochar-amended completely decomposed granite (CDG). Soil specimens were prepared by mixing CDG with two types of biochar at a mass ratio of 5% and compacted at 95% of the maximum dry density. Although the peak shear strength of biochar-amended CDG is reduced by up to 20% because of lower initial dry density of the soil and crushing of biochar particles during shearing, both types of biochar have negligible effects on the ultimate shear strength, which is governed by friction between soil particles. This highlights that the ultimate friction angle can be adopted for designing bio-engineered slopes using biochar-amended soils.