Environmental Geochemistry and Health最新文献

This study applies a Screening-Level Ecological Risk Assessment (SLERA) to evaluate the potential impact of trace elements on vegetation in an abandoned As-Cu mining area in northern Spain. A total of 27 soil samples were analyzed for pseudo-total (aqua regia) and phyto-available (EDTA 0.05 M) content of As, Cd, Co, Cr, Cu, Ni, Pb and Zn. Contamination and ecotoxicological risk indices were used to identify pollution hotspots and contaminants of ecological concern (COPEC). Arsenic, Cu, Co and Zn pose a potential risk to vegetation across the site. Available concentrations of these elements are high, although average phyto-availabilities are generally low (< 30%). Remarkably, some highly contaminated areas support vegetation, while others remain barren. This suggests that high phyto-available concentrations alone do not fully explain the presence or absence of vegetation. Edaphic properties, such as low soil pH and minimal organic matter content, seem to play a critical role in inhibiting vegetation growth in certain areas. These results underline the importance of considering not only trace element concentrations but also site-specific edaphic properties when assessing ecological risk and planning remediation strategies in contaminated mining areas.

The occurrence of microplastics in athletic fields and their risk of ecological pollution have attracted widespread attention. The abundance, particle size, morphology, color and type of microplastics as well as their ecological risk are conducted in five types of athletic fields runoff on a campus in Beijing. The concentration of microplastics in the stormwater runoff of the five athletic fields ranges 2433 ± 493 to 5067 ± 839 particles/L, composed of fibers, granules and fragments. Fibers microplastics (41-64%) are the most abundant in stormwater runoff samples from most athletic fields, followed by granules (26-45%), and fragments (8-18%). ATR-FTIR and micro-FTIR identify the types of microplastics in runoff from athletic fields as EPDM, SBR, PE, PP, PO, rayon, and nylon. The degree of microplastic pollution is ranked level II-III pollution, which posing potential health and ecological risks. The adsorption behavior is tested for three types of microplastic particles including ethylene propylene diene monomer (EPDM), styrene-butadiene rubber (SBR) and aged-SBR particles derives from athletic fields surface materials towards runoff typical heavy metals Pb and Zn. The adsorption isotherms are more in line with the Langmuir model, indicating a chemical monolayer adsorption. The maximum adsorption capacity towards Pb and Zn follow the order of EPDM (2.67 mg/g) > aged-SBR (1.50 mg/g) > SBR (0.13 mg/g), and EPDM (2.61 mg/g) > aged-SBR (1.50 mg/g) > SBR (0.56 mg/g), respectively. Aged microplastics are subjected to processes such as UV aging and weathering, the surface layer is more likely to acquire charges and adsorb metals to maintain charge balance. EPDM, SBR and aged-SBR particles all contain Ca, Zn, and Mg, which can undergo displacement reactions with Pb and Zn. FTIR results indicate that the adsorption of heavy metals may alter the surface chemical properties of microplastics, rendering them more polar. XPS results reveal that the changes in surface functional groups of EPDM are more pronounced before and after adsorption compared to SBR and aged-SBR, indicating that chemical adsorption plays a dominant role in this process. Microplastics in runoff from athletic fields is an important source of microplastic release, and the occurrence of microplastics needs to attract further attention. The adsorption of microplastics and pollutants in athletic field runoff could exacerbate their combined pollution, thus their ecological risks cannot be ignored.

Research on the associations between PM_2.5 and total respiratory diseases (RD) in Lanzhou is limited. We investigated the short-term impact of PM_2.5 on total RD hospitalizations in Lanzhou (2015-2019) using various exposure metrics. We collected data on hospitalizations, daily air pollutant concentrations, and meteorological factors during the study period. Daily excessive concentration hours (DECH) were calculated according to the World Health Organization's air quality guidelines. A distributional lag nonlinear model (DLNM) based on a generalized additive model (GAM) was used to comparatively analyze the association between three PM_2.5 exposure metrics (DECH (DECH PM_2.5), daily mean concentration (Mean PM_2.5), and hourly peak concentration (Peak PM_2.5)) and RD hospitalizations. Subgroup analyses and sensitivity analyses were also performed. We found similar effects on RD hospitalizations using DECH PM_2.5 and Mean PM_2.5, but relatively weak associations observed using Peak PM_2.5. The cumulative lag effect increased daily. Subgroup analyses showed that females and children aged 0-17 years were more susceptible to PM_2.5 pollution and that the association was enhanced during the cold season. Our research strengthened the evidence that exposure to ambient PM_2.5 increases the risk of RD. This study revalidated the reliability of the new metrics and confirmed that DECH PM_2.5 effect estimates for exposure-disease were more accurate than the Mean PM_2.5.

The coal extraction process often results in the generation of significant amounts of waste materials. Mineral coal waste from the coal region of Coahuila poses significant environmental challenges due to its accumulation in surrounding areas. However, repurposing this waste presents opportunities for various applications, including the removal of water contaminants. This study evaluated the potential of mineral coal waste as an adsorbent material for Cr (VI). The waste underwent neutral (LN) and acid washing (LA) to compare the effects of these treatments on its properties. Characterization methods included proximate analysis, thermogravimetric analysis, X-ray fluorescence, X-ray diffraction, FTIR, scanning electron microscopy, contact angle and zero-point charge determination. Adsorption conditions were optimized varying pH, temperature and adsorbent mass. The highest removal efficiency was achieved with acid-washed material at a pH of 3, an adsorbent-to-solution ratio of 5 g/L, and a temperature of 45 °C, with pH identified as the most significant variable. Experimental isotherm data aligned with the Langmuir model, revealing a maximum adsorption capacity (Qmax) of 1.41 mg/g for the LA material. Kinetic data were best described by the pseudo-second-order model, with a maximum contact time of 48 h yielding 67.54% removal efficiency for a 5 mg/L Cr (VI) solution. Acid washing was found to reduce the ash content of the material, enhancing its adsorption performance.

This paper discusses information collected from original articles published between 1992 and 2022 regarding heavy metals (HMs) contamination in various environments across Mexico. The primary aim of this work was to identify the Mexican states where concentrations of HMs have been reported to exceed the maximum permissible limits for several types of soil, water, and sediment according to Mexican standards NOM-147-SEMARNAT/SSA1-2004, NOM-127-SSA1-2021, as well as international standards. The data collected indicates that 25 states in Mexico have reported at least one metal exceeding the maximum permissible limits in soil. Among these, Zacatecas, Nuevo Leon and Chihuahua had the highest number of HMs exceeding the standards. For sediment contamination, 26 states exceeded the permissible limits, with San Luis Potosí and Guerrero showing the highest number of HMs above the standards. Additionally, 26 states have reports of HMs exceeding the permissible limits in water, with Guanajuato and Guerrero having the highest number of HMs. Interestingly, the most frequent metals reported as soil contaminants are Cu, Fe, Pb and Zn; in sediment, they are Cd, Cr, Cu, Fe, Pb and Zn; and in water, they are Cd, Cr, Cu, Fe, Mn, Pb and Zn. The compiled information indicates that the primary anthropogenic sources of HMs release in Mexico include industrial activities, urban wastewater, mining, and agricultural practices. Furthermore, the data analyzed highlights several serious health risks associated with exposure to HMs, including cancer, central nervous system damage, DNA damage, and issues related to kidneys and lungs. This paper provides a comprehensive overview of HMs contamination in Mexico as well as the health challenges that arise from this contamination..

Plant-growth-promoting bacteria (PGPB) and biochar have attracted increasing attention for remediating the combined pollution of arsenic (As) and cadmium (Cd) and promoting selenium (Se) biofortification. However, their differing effects on the bioavailability of As, Cd, and Se and their absorption by rice are still poorly understood. In this study, PGP Agrobacterium sp. T3F4 with Se- oxidizing capacity and corn straw biochar were applied to natively polluted paddy soil. Strain T3F4 reduced the bioavailability of As in soil but increased bioavailable Se, decreasing the As content in rice by 16.8% and improving the Se content of rice by 54.5% (p < .05). Application of 2.5% biochar stimulated iron (Fe) plaque formation of the root and immobilized As and Cd in the soil, decreasing the As and Cd absorption of rice by 14.7% and 40.3%, respectively (p < .05). Application of 5.0% biochar achieved similar mitigation effects for As and Cd but also decreased the Se content in rice by 60.6% by reducing bioavailability. This decrease in Se uptake was mitigated when 5.0% biochar was co-applied with strain T3F4. Notably, applying strain T3F4 also alleviated the oxidative stress on rice plants and enhanced soil enzyme activities, contributing to a substantial increase in grain yield in the polluted paddy soil. The adverse effects of 5.0% biochar on soil health and grain yield were mitigated by the co-application of strain T3F4. Our results provide new insights into applying PGPB and biochar for Se biofortification and As and Cd remediation in paddy soil.

Heavy metal contamination represents a critical environmental and public health challenge, necessitating effective remediation approaches. This study examines the bioremediation potential of three indigenous bacterial strains Aeromonas caviae KQ_21, Aeromonas hydrophila AUoR_24, and Shewanella putrefaciens SUoR_24 evaluated both individually and in consortia for their capacity to remove heavy metals. Tolerance assessments demonstrated that the coculture of these strains exhibited superior resistance to copper (Cu), zinc (Zn), and nickel (Ni), with optimal growth observed up to 6 mM for Cu, 9 mM for Zn, and 5 mM for Ni, outperforming the monocultures. The co-culture system also achieved higher metal reduction efficiencies, with reductions of 47.02% for Cu, 61.49% for Ni, and 61.93% for Zn, in contrast to lower reductions observed in individual strains. The study further explored the impact of environmental conditions on bioremediation efficiency. Optimal temperature for both monoculture and coculture setups was found to be 30 °C. pH and salt concentration variations significantly affected bacterial growth and metal reduction, highlighting the necessity of tailored conditions for enhanced bioremediation. In terms of metal removal mechanisms, the results demonstrated that nickel (Ni) removal occurred primarily through bioaccumulation, while copper (Cu) removal involved both biosorption and bioaccumulation. Zinc (Zn) removal was facilitated through biosorption, bioaccumulation, and biotransformation. These findings underscore the effectiveness of bacterial consortia, particularly indigenous strains, in improving heavy metal tolerance and reduction through synergistic interactions and cooperative metabolic processes. This research offers valuable insights into optimizing bacterial consortia for environmental cleanup and advances the application of indigenous bacteria in bioremediation strategies. Future investigations should focus on exploring additional microbial species and further elucidating the molecular mechanisms that contribute to enhanced bioremediation efficacy.

The riparian zone serves as an ecological transition area between aquatic and terrestrial environments. Understanding the spatial distribution and origins of heavy metals within this zone is crucial for studying riverine ecosystems. In this research, we assessed the occurrence forms and spatial patterns of heavy metals in the riparian zone of the Shaying River Basin in Zhoukou City. Environmental risks were preliminarily evaluated using indices such as I_geo, RI, and PLI, and the sources of heavy metals were identified through PMF. The results revealed that the overall ecological risk associated with eight analyzed heavy metals (Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn) in this region was low. However, Cd is marked enriched and represents a significant factor contributing to the potential ecological risk within the riparian zone of the basin. The high bioavailability of Cd and Mn in the soils of nine more contaminated sites showed moderate to very high ecological risk. The PMF model identified four pollution primary sources in this region: agricultural and industrial activities (29.4%), upstream water pollution (21.1%), natural sources (26.5%), and transport-related source (23.1%). These findings establish a scientific foundation for the conservation and management of the ecological environment in the riparian zone of the Shaying River Basin in Zhoukou City. Additionally, they will serve as a reference for future research on soil heavy metal migration and sources within the Huaihe River Basin, China.

The management of fluorescent lamps wastes is a challenge, and its disposal in soils may cause harmful effects on human health and edaphic biota due to the presence of Hg and other potentially toxic metals. However, the pedogeochemical behavior of metals from fluorescent lamps is still rarely studied in the tropics. An Oxisol sample was contaminated in the laboratory using a dosage of 6.5% fluorescent lamp powder relative to the mass of soil. The mobility of metals was assessed through a sequential extraction protocol of the Community Bureau of Reference. To assess potential risks, a mathematical model of Human Health Risk Assessment was employed, based on human exposure on metal-contaminated groundwater from soil contamination. Evaluation of metal mobility showed that 6% of Ni and 30% of Cu in contaminated soil were in the potentially bioavailable fraction. The slightly acidic pH of the contaminated soil seems to influence the mobility of Ni and Cu. Zn and Pb were mainly found in the residual fraction, suggesting low geochemical availability. However, over time, metals may be leached, highlighting the importance of monitoring disposal areas. When these results are compared to the mobility profile found in extractions applied to pure fluorescent lamps waste, the data suggest that soil properties tend to reduce metal mobility. Human Health Risk Assessment showed significant risks associated with the human consumption of Cu-contaminated groundwater, considering a scenario of metal leaching from the soil. This study highlights the need for proper fluorescent lamps disposal in tropical terrestrial systems to prevent ecological and public health risks.