Edible muscle tissues of Solea solea, Mullus barbatus, and Sardina pilchardus marketed in Mersin were analyzed for their Cr (total), Mn, Fe, Ni, Cu, Zn, As (total), Cd, Sn, and Pb levels. Metal levels of the tissues were determined using inductively coupled plasma-mass spectrophotometric (ICP-MS) methods. Muscle levels of Cr, Mn, Fe, Ni, Cu, Zn, As, Sn, and Pb were determined as 0.19–2.80, 0.08–3.88, 0.93–25.76, 0.03–0.63, 0.01–1.96, 1.28–45.95, 0.49–25.26, 0.14–4.03, and 0.02–1.37 mg kg⁻¹ w.w., respectively. Cadmium levels were below detection limits in all the muscle samples taken. Mean metal levels of the tissues were compared with the provisional tolerable daily (PTDs) and weekly (PTWIs) intake limits. Mean metal levels taken by the consumption of analyzed tissues were below PTDs and PTWIs; hence, the fish species studied do not pose any risk for human consumption from the point of heavy metals.

Large volumes of excavated rock are produced as a result of road and railway tunnel construction in Hokkaido, Japan. Due to the geological condition of this region, these rocks have often undergone hydrothermal alterations, causing them to contain elevated amounts of hazardous elements including arsenic (As). Therefore, these excavated rocks are potentially hazardous waste, and proper disposal methods are required. In this article, performance of unsaturated river sediment on immobilizing As from hydrothermally altered rock is evaluated using laboratory column experiments and Hydrus-1D. The results reveal that the river sediment significantly reduces As migration. Arsenic retarded by river sediment was observed in three patterns. The first was an adsorption onto minerals originally contained in the river sediment. The next pattern was a combination of reduction of As generation by oxidation of As bearing-minerals, irreversible adsorption, and adsorption onto newly precipitated Fe oxy-hydroxide/oxide. The last pattern led to a further depletion of As leached from the rock layer due to a shift in the majority of the As generation mechanism from dissolution to oxidation in combination with a low concentration of oxygen in the rock layer. These patterns were satisfactorily evaluated by a Hydrus-1D model with reversible and irreversible adsorptions. The information from this work is effective in designing and establishing a reasonable technique for the disposal of hydrothermally altered rocks.

Spontaneous colonization of mine tailing dams by plants is a potential tool for phytostabilization of such reservoirs. However, the physical and chemical properties of each mine tailings deposit determine the success of natural plant establishment. The plant Baccharis linearis is the main native nanophanerophyte species (evergreen sclerophyllous shrub) that naturally colonizes abandoned copper tailings dams in arid to semiarid north-central Chile. This study compare growth of B. linearis against the physical and chemical properties of a Technosol derived from copper mine tailings. Five sites inside the deposit were selected based on B. linearis vegetation density (VD), at two soil sampling depths under the canopy of adult individuals. Physical and chemical properties of tailings samples and nutrient concentrations in tailings and plants were each determined. Some morphological features of the plants (roots and aerial parts) were also quantified. There were significant differences in soil available water capacity (AW) and relative density (Rd) at different VD. Sites with low AW and high Rd had lower nutrient concentrations and higher Zn content in tailings, decreased infection by arbuscular mycorrhizal fungi, and increased fine root abundance and root hair length in individual plants. In contrast, higher AW, which was positively correlated with fine particles and organic matter content, had a positive effect on vegetation coverage, increased N and P contents in tailings, and increased N contents in leaf tissues, even when available N and P levels in tailings were low. Multiple constraints, such as low AW, N, P, and B contents and high Zn concentrations in the tailings restricted vegetation coverage, but no phenotypic differences were observed between individuals. Thus, in order to promote dense coverage by B. linearis, water retention in these tailings must be improved by increasing colloidal particles (organic and/or inorganic) contents, which have a positive effect on colonization by this species.

Carbon sequestration is an indispensable ecosystem service provided by soil and vegetation, so mapping and valuing the carbon budget by considering both ecological and social factors is an important trend in evaluating ecosystem services. In this work, we established multiple scenarios to evaluate the impacts of land use change, population growth, carbon emission per capita, and carbon markets on carbon budget. We quantified carbon sinks (aboveground and belowground) under different scenarios, using the Carnegie-Ames-Stanford Approach (CASA) model and an improved carbon cycle process model, and studied carbon sources caused by human activities by analyzing the spatial distribution of human population and carbon emission per capita. We also assessed the net present value (NPV) for carbon budgets under different carbon price and discount rate scenarios using NPV model. Our results indicate that the carbon budget of Guanzhong-Tianshui Economic Region is surplus: Carbon sinks range from 1.50 × 10¹⁰ to 1.54 × 10¹⁰ t, while carbon sources caused by human activities range from 2.76 × 10⁵ to 7.60 × 10⁵ t. And the NPV for carbon deficits range from 3.20 × 10¹¹ RMB to 1.52 × 10¹² RMB. From the perspective of ecological management, deforestation, urban sprawl, population growth, and excessive carbon consumption are considered as the main challenges in balancing carbon sources and sinks. Levying carbon tax would be a considerable option when decision maker develops carbon emission reduction policies. Our results provide a scientific and credible reference for harmonious and sustainable development in the Guanzhong-Tianshui Economic Region of China.

The objective of this study was to evaluate the influence of the soil parameters (particle size, initial contamination level, etc.) on the performances of an attrition process to remove As, Cr, Cu, pentachlorophenol (PCP) and dioxins and furans (PCDD/F). Five different contaminated soils were wet-sieved to isolate five soil fractions (< 0.250, 0.250–1, 1–4, 4–12 and > 12 mm). Five attrition steps of 20 min each, carried out in the presence of a biodegradable surfactant ([BW] = 2%, w w⁻¹) at room temperature with a pulp density fixed at 40% (w w⁻¹), were applied to the coarse soil fractions (> 0.250 mm) of different soils. The results showed good performances of the attrition process to simultaneously remove PCP and PCDD/F from contaminated soil fractions initially containing between 1.1 and 13 mg of PCP kg⁻¹ (dry basis) and between 1795 and 5720 ng TEQ of PCDD/F kg⁻¹. It appeared that the amounts of contaminants removed were significantly correlated (p value < 0.05, R ² = 0.96) with the initial amounts of PCP and PCDD/F, regardless of the particle size of the soils studied. The nature of the soil (granulometric distribution, pH, total organic carbon (TOC) (organic matter) and diverse industrial origin) slightly and negatively influenced the efficiency of organic contaminants removals using attrition. However, the attrition treatment allowed an efficient removal of both PCP and PCDD/F from the coarse fraction of contaminated soil, despite the nature of the soil.

The objectives of the present study are to isolate thiosulfate-degrading bacterium and optimize its degradative conditions including temperature, pH, and thiosulfate concentrations required for bioremediation purposes. A heterotrophic thiosulfate-degrading bacterial strain DT was successfully isolated from saline soil and identified as Altererythrobacter sp. based on its physicochemical properties and 16S rDNA sequence analysis. It was a naturally occurring methionine auxotrophic strain that utilized only peptone, yeast extract, or several amino acids as the sole carbon source. Altererythrobacter sp. DT degraded thiosulfate via a distinctive disproportionation reaction which was characterized by accumulation of sulfate and elemental sulfur at a molar ratio of 1:1. Optimal conditions for both bacterial growth and thiosulfate metabolism were 25–30 °C and pH 6, respectively. In a fed-batch treatment system receiving liquid polysulfide wastewater, a high degradation rate of 407.3 mg S₂O₃²⁻/(L h) and an elemental sulfur yield of nearly 50% were achieved for immobilized DT cells, indicating great potential of strain DT for future application in the treatment of and microbial production of elemental sulfur from thiosulfate-bearing industrial wastewater.

The Pantanal is an extensive flooded plain, rich in biodiversity and considered a Biosphere Reserve and World Heritage Site. It has great complexity and can be divided into regions due to its each distinct characteristic. Nhecolândia is a very peculiar region because it is made up of thousands of freshwater and brackish ponds. The study objective was to evaluate the physical-chemical parameters of the Nhecolândia ponds and to analyze the vegetation indexes generated from UAV aerial photographs in order to identify what best distinguishes freshwater and brackish ponds and to differentiate study area features. The in-field and image data collection were performed on June 20, 2015. The aerial photographs were processed to obtain mosaic which served as a vegetation index basis. The indexes and wavelengths in the visible region analyses were performed for each of the area’s ponds. It was observed that bays and salines have a differentiated spectral behavior. The excess green and normalized excess green vegetation indexes presented results enough to separate freshwater from brackish ponds, plus to differentiate many study area features.

Stormwater wetlands collect and attenuate runoff-related herbicides, limiting their transport into aquatic ecosystems. Knowledge on wetland bacterial communities with respect to herbicide dissipation is scarce. Previous studies showed that hydrological and hydrochemical conditions, including pesticide removal capacity, may change from spring to summer in stormwater wetlands. We hypothesized that these changes alter bacterial communities, which, in turn, influence pesticide degradation capacities in stormwater wetland. Here, we report on bacterial community changes in a stormwater wetland exposed to pesticide runoff, and the occurrence of trz, atz, puh, and phn genes potentially involved in the biodegradation of simazine, diuron, and glyphosate. Based on T-RFLP analysis of amplified 16S rRNA genes, a response of bacterial communities to pesticide exposure was not detected. Changes in stormwater wetland bacterial community mainly followed seasonal variations in the wetland. Hydrological and hydrochemical fluctuations and vegetation development in the wetland presumably contributed to prevent detection of effects of pesticide exposure on overall bacterial community. End point PCR assays for trz, atz, phn, and puh genes associated with herbicide degradation were positive for several environmental samples, which suggest that microbial degradation contributes to pesticide dissipation. However, a correlation of corresponding genes with herbicide concentrations could not be detected. Overall, this study represents a first step to identify changes in bacterial community associated with the presence of pesticides and their degradation in stormwater wetland.

This study proposes a method, backpropagation (BP) neural network, for interpolating missing values in daily precipitation time series. Firstly, the BP neural network is adopted to interpolate missing daily rainfall data at three selected stations in Yantai, Shandong, China. Then, the temporal and spatial variations in precipitation extremes across Shandong are analyzed by utilizing the complete daily rainfall dataset derived from accurate propagation at 24 meteorological stations. The results show that the long-term trends in five selected extreme precipitation indices calculated from interpolated daily rainfall data are generally consistent with those from original nonmissing values. And the spatial patterns of trends in precipitation extremes also show better performance for BP neural network approach in interpolating missing daily rainfall gaps. Those suggest that this BP neural network algorithm can obtain a good fit in terms of space-time variability of regional precipitation extremes, in case that the correlation coefficients between the target stations with missing values and reference stations with complete daily rainfall dataset are relatively large. These findings could be crucial for investigating regional frequency of heavy rainfall and water resource management.

Sorption of antibiotics to clay minerals is a key process controlling their transport and fate in environment. In this study, the effects of pH, ionic strength, and Cu(II) on ofloxacin (OFL) sorption to kaolinite were investigated by batch sorption experiments. The results of sorption edge experiments suggested that OFL sorption to kaolinite was pH and ionic strength dependent. Cation exchange was a major contributor to the sorption of OFL⁺ to kaolinite. The decreased OFL sorption with increasing ionic strength indicated the formation of outer-sphere complexation. When solution pH was lower than 7.0, Cu-OFL complexes facilitated OFL sorption through electrostatic attraction or formation of kaolinite-Cu-OFL and kaolinite-OFL-Cu ternary surface complexes. However, existence of free Cu(II) cation in solution competed for sorption sites, and thus suppressed OFL sorption. When solution pH was higher than 7.0, Cu(II) existed as Cu(OH)₂, and the Cu-OFL complexes in aqueous phase and solid phase (precipitation) enhanced OFL removal efficiency from solution. The results imply that Cu(II) effects should be taken into account in the evaluation of OFL mobility in environment.