The Wiśniówka rock strip mining area (south-central Poland) with quartzite quarries, acid water bodies and tailings piles is one of the most unique acid mine drainage (AMD) sites throughout the world. This is due to the occurrence of enormous amounts of pyrite unknown in sedimentary formations worldwide. Of the two mineralization zones, one that is the most abundant in arsenical pyrite occurs in the lowermost Upper Cambrian formation of the Podwiśniówka quarry. The As-rich pyritiferous clastic rocks are exposed as a result of deep quartzite extraction during 2013–2014. In addition, the clayey-silty shale interbeds are enriched in rare earth element (REE) minerals. The mining operation left an acidic lake with a pH of about 2.4–2.6 and increased contents of sulfates, metal(loid)s and REE. The Podwiśniówka pyrite-rich waste material was stacked up in many places of the mining area giving rise to strongly acidic spills that jeopardized the neighboring environment. One of these unexplored tailings piles was a source of extremely sulfate- and metal(loid)-rich pools with unusual enrichments in As (up to 1548 mg L⁻¹) and REE (up to 24.84 mg L⁻¹). These distinctly exceeded those previously reported in the Wiśniówka area. A broad scope of geochemical, mineralogical and petrographic methods was used to document these specific textural and mineralogical properties of pyrite facilitating its rapid oxidation. The pyrite oxidation products reacted with REE-bearing minerals releasing these elements into acid water bodies. Statistical methods were employed to connect the obtained tailings pool hydrogeochemical data with those derived from this and the previous studies of the Podwiśniówka and Wiśniówka Duża acid pit lakes. In contrast to metal(loid) profiles, the characteristic shale-normalized REE concentration patterns turned out to be more suitable for solving different AMD issues including provenance of mine waste material in the tailings pile examined.

This study developed a novel Hg(II) immobilization strategy by firstly incubating algal cells in high-phosphate cultures for surface modification, followed by obtaining the P-rich biomass as adsorbents for enhanced Hg(II) removal and then charring the Hg-loaded biomass to prevent leaching of phosphate and to immobilize Hg(II). For algal surface modification, Scenedesmus obtusus XJ-15 were cultivated under different P concentrations and obtained the highest sites concentration of surface phosphoryl functional groups in 80 mg L⁻¹ P cultures. For Hg(II) adsorption, biomass from 80 mg L⁻¹ P cultures (B-80) achieved the highest saturated sorption capacity of 95 mg g⁻¹ fitting to Langmuir isotherm model under the optimum pH of 5.0. For charring stabilization, the Hg-loaded B-80 was calcinated under different temperatures, and the product obtained from 300 °C charring showed the lowest Hg(II) leaching rate without P release. Moreover, FT-IR and XPS analysis indicate that the surge of surface phosphoryl functional groups dominated the enhancement of Hg(II) sorption and also Hg(II) charring immobilization. The above results suggested that the developed strategy is promising for both phosphate and mercury removal from water and for co-immobilization of P and Hg(II) to prevent leaching.

Dyeing wastewaters are toxic and carcinogenic to both aquatic life and human beings. Adsorption technology, as a facile and effective method, has been extensively used for removing dyes from aqueous solutions for decades. Numerous researchers have attempted to seek or design alternative materials for dye adsorption. However, using various novel adsorbents to remove dyes has not been extensively reviewed before. In this review, the key advancement on the preparation and modification of novel adsorbents and their adsorption capacities for dyes removal under various conditions have been highlighted and discussed. Specific adsorption mechanisms and functionalization methods, particularly for increasing adsorption capacities are discussed for each adsorbent. This review article mainly includes (1) the categorization, side effects and removal technologies of dyes; (2) the characteristics, advantages and limitations of each sort of adsorbents; (3) the functionalization and modification methods and controlling mechanisms; and (4) discussion on the problems and future perspectives about adsorption technology from adsorbents aspects and practical application aspects.

Diagenetic sediment phosphorus (P) recycling is a widespread phenomenon, which causes degradation of water quality and promotes harmful algal blooms in lakes worldwide. Strong P coupling with iron (Fe) in some lakes is thought to inhibit diagenetic P efflux, despite elevated P concentrations in the sediment. In these sediments, the high Fe content leads to P scavenging on ferric Fe near the sediment surface, which increases the overall P retention. Reduced external Fe inputs in such lakes due to industrial pollution control may lead to unintended consequences for sediment P retention. Here, we study sediment geochemistry and sediment-water interactions in the historically polluted Hamilton Harbour (Lake Ontario, Canada) which has undergone 30 years of restoration efforts. We investigate processes controlling diagenetic P recycling, which has previously been considered minor due to historically high Fe loading. Our results demonstrate that present sediment P release is substantial, despite sediment Fe content reaching 6.5% (dry weight). We conclude that the recent improvement of wastewater treatment and industrial waste management practices has reduced Fe pollution, causing a decrease in diagenetically reactive Fe phases, resulting in the reduction of the ratio of redox-sensitive P and Fe, and the suppression of P scavenging on Fe oxyhydroxides.

Organic aerosol (OA) are always the most abundant species in terms of relative proportion to PM₂.₅ concentration in Beijing, while in previous studies, poor link between carbonaceous particles and their gaseous precursors were established based on field observation results. Through this study, we provided a comprehensive analysis of critical carbonaceous species in the atmosphere. The concentrations, diurnal variations, conversions, and gas-particle partitioning (F-factor) of 8 carbonaceous species, carbon dioxide (CO₂), carbon monoxide (CO), methane (CH₄), volatile organic compounds (VOCs), non-methane hydrocarbon (NMHC), organic carbon (OC), elemental carbon (EC), and water soluble organic compounds (WSOCs), in Beijing were analyzed synthetically. Carbonaceous gases (CO, CO₂, VOCs, and CH₄) and OC/EC ratios exhibited double-peak diurnal patterns with a pronounced midnight peak, especially in winter. High correlation between VOCs and OC during winter nighttime indicated that OC was formed from VOCs precursors via an unknown mechanism at relative humidity greater than 50% and 80%, thereby promoting WSOC formation in PM₁ and PM₂.₅ respectively. The established F-factor method was effective to describe gas-to-particle transformation of carbonaceous species and was a good indicator for haze events since high F-factors corresponded with enhanced PM₂.₅ level. Moreover, higher F-factors in winter indicated carbonaceous species were more likely to exist as particles in Beijing. These results can help gain a comprehensive understanding of carbon cycle and formation of secondary organic aerosols from gaseous precursors in the atmosphere.

Effects of CeO2 NPs (200 mg.L−1) on rice (Oryza sativa L.) alone or co-exposure with cadmium (Cd) and salt (sodium chloride, NaCl) were investigated in hydroponic systems for two weeks. Physiological results show that rice biomass was significantly inhibited when NaCl or CdCl2 added alone or in co-exposure treatment. CeO2 NPs significantly relieve the chlorophyll damage under CdCl2 environmental stress. The presence of CeO2 NPs alleviated both stressors induced damages to rice as indicated by the reduced proline level. Additionally, CeO2 NPs triggered the antioxidant defense systems to counteract the oxidative stress caused by NaCl and CdCl2. The level of 8-OHdG, one of the most important indicators for genotoxicity, in rice suggest that the presence of CeO2 NPs reduced the DNA damage in NaCl treated rice. Elemental analysis indicated that co-exposure to NaCl and CdCl2 slightly decreased the Cd content as compared to the one in the CdCl2 alone treatment, and this co-exposure also significantly reduced the Na content when comparing with the NaCl alone treatment. Taken together, our findings suggest that CeO2 NPs could alleviate the CdCl2 and NaCl stresses, but could not completely change the phenotype of both contaminants treated rice.

In modern society, the intense vehicle traffic and the lack of effective mitigating strategies may adversely impact freshwater systems. Road-deposited sediments (RDS) accumulate a variety of toxic substances which are transported into nature during hydrologic events, mainly affecting water bodies through stormwater runoff. The aim of this study was to evaluate the RDS metal enrichment ratio between the end of wet season and the middle of the dry season for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn in samples from Natal, Brazil. Twenty RDS, drainage system and river sediment samples were collected in the wet and dry seasons using a stainless-steel pan, brush and spatula. In the laboratory, the samples were submitted to acid digestion and heavy metal concentrations were measured by atomic absorption spectrometry (AAS). A consistent RDS enrichment by heavy metals in dry season samples was followed by an increase in the finest particle size fraction (D < 63 μm). Maximum concentrations were 5, ND, 108, 23810, 83, ND, 77 and 150 mg kg⁻¹ for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn, respectively. The RDS enrichment ratio was Cr(1.3 ×), Cu(2.6 ×), Fe(3.3 ×), Mn(1.5 ×), Pb(1.5 ×) and Zn(2.1 ×). The Geo-accumulation Index values showed that RDS were moderately polluted for Cu and slighted polluted for Zn and Pb. Principal Component Analysis (PCA) showed that the accumulation of toxic heavy metals decreased according to water flow.

Effective measures for protecting and preserving the marine environment require an understanding of the potential impact of anthropogenic sound on marine life. A crucial component is a proper assessment of the anthropogenic soundscape: which sounds are present where, when and how strong? We provide an extensive case study modelling the spatial, temporal and spectral distribution of sound radiated by several anthropogenic sources (ships, seismic airguns, explosives) and a naturally occurring one (wind) in the Dutch North Sea. We present the results as a series of sound maps covering the whole of the Dutch North Sea, showing the spatial and temporal distribution of the energy from these sources. Averaged over a two year period, shipping is responsible for the largest amount of acoustic energy (∼1800 J), followed by seismic surveys (∼300 J), explosions (∼20 J) and wind (∼20 J) in the frequency band between 100 Hz and 100 kHz. Our study shows that anthropogenic sources are responsible for 100 times more acoustic energy (averaged over 2 years) in the Dutch North Sea than naturally occurring sound from wind. The potential impact of these sounds on aquatic animals depends not only on these temporally averaged and spatially integrated broadband energies, but also on the source-specific spatial, spectral and temporal variation. Shipping is dominant in the southern part and along the coast in the north, throughout the years and across the spectrum. Seismic surveys are relatively local and spatially and temporally dependent on exploration activities in any particular year, and spectrally shifted to low frequencies relative to the other sources. Explosions in the southern part contribute wide-extent high energy bursts across the spectrum. Relating modelled sound fields to the temporal and spatial distribution of animal species may provide a powerful tool for understanding the potential impact of anthropogenic sound on marine life.

An accurate estimation of PM2.5 (fine particulate matters with diameters ≤ 2.5 μm) concentration is critical for health risk assessment and generating air pollution control strategies. In this study, a hybrid remote sensing and machine learning approach, named RSRF model is proposed to estimate daily ground-level PM2.5 concentrations, which integrates Random Forest (RF), one of machine learning (ML) models, and aerosol optical depth (AOD), one of remote sensing (RS) products. The proposed RSRF model provides an opportunity for an adequate characterization of real-time spatiotemporal PM2.5 distributions at uninhabited places and complex surfaces. It also offers advantages in handling complicated non-linear relationships among a large number of meteorological, environmental and air pollutant factors, as well as ever-increasing environmental data sets. The applicability of the proposed RSRF model is tested in the Beijing-Tianjin-Hebei region (BTH region) during 2015–2017. Deep Blue (DB) AOD from Aqua-retrieved Collection 6.1 (C_61) aerosol products of Moderate Resolution Imaging Spectroradiometer (MODIS) is validated with Aerosol Robotic Network. The validation results indicate C_61 DB AOD has a high correlation with ground based AOD in the BTH region. The proposed RSRF model performed well in characterizing spatiotemporal variations of annual and seasonal PM2.5 concentrations. It not only is useful to quantify the relationships between PM2.5 and relevant factors such as DB AOD, meteorological and air pollutant variables, but also can provide decision support for air pollution control at a regional environment during haze periods.