Characterization of the inhalable fraction (< 10 µm) of soil from highly urbanized and industrial environments: magnetic measurements, bioaccessibility, Pb isotopes and health risk assessment.

Soil in urban and industrial areas is one of the main sinks of pollutants. It is well known that there is a strong link between metal(loid)s bioaccessibility by inhalation pathway and human health. The critical size fraction is < 10 µm (inhalable fraction) since these particles can approach to the tracheobronchial region. Here, soil samples (< 10 µm) from a highly urbanized area and an industrialized city were characterized by combining magnetic measurements, bioaccessibility of metal(loids) and Pb isotope analyses. Thermomagnetic analysis indicated that the main magnetic mineral is impure magnetite. In vitro inhalation analysis showed that Cd, Mn, Pb and Zn were the elements with the highest bioaccessibility rates (%) for both settings. Anthropogenic sources that are responsible for Pb accumulation in < 10 µm fraction are traffic emissions for the highly urbanized environment, and Pb related to steel emissions and coal combustion in cement plant for the industrial setting. We did not establish differences in the Pb isotope composition between pseudo-total and bioaccessible Pb. The health risk assessment via the inhalation pathway showed limited non-carcinogenic risks for adults and children. The calculated risks based on pseudo-total and lung bioaccessible concentrations were identical for the two areas of contrasting anthropogenic pressures. Carcinogenic risks were under the threshold levels (CR < 10-4), with Ni being the dominant contributor to risk. This research contributes valuable insights into the lung bioaccessibility of metal(loids) in urban and industrial soils, incorporating advanced analytical techniques and health risk assessments for a comprehensive understanding.

Geochemistry and origin of inorganic contaminants in soil, river sediment and surface water in a heavily urbanized river basin.

Understanding the geochemistry and contamination of rivers affected by anthropogenic activities is paramount to water resources management. The Asopos river basin in central Greece is facing environmental quality deterioration threats due to industrial, urban and agricultural activities. Here, the geochemistry of river sediments and adjacent soil in terms of major and trace elements (Al, Ca, Mg, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) and the geochemical composition of surface water in terms of major ions, trace elements and nutrients along the Asopos river basin were determined. In addition, this study characterized potential nitrate sources through the analysis of stable isotope composition of NO3- (δ15Ν-ΝΟ3- and δ18Ο-ΝΟ3-). Results indicated that specific chemical constituents including nutrients (NO2-, NH4+, PO43-) and major ions (Na+, Cl-) were highest in the urban, industrialized and downstream areas. On the other hand, nitrate (NO3-) concentration in river water (median 7.9 mg/L) showed a decreasing trend from the upstream agricultural sites to the urban area and even more in the downstream of the urban area sites. Ionic ratios (NO3-/Cl-) and δ15Ν-ΝΟ3- values (range from +10.2 ‰ to +15.7 ‰), complemented with a Bayesian isotope mixing model, clearly showed the influence of organic wastes from septic systems and industries operating in the urban area on river nitrate geochemistry. The interpretation of geochemical data of soil and river sediment samples demonstrated the strong influence of local geology on Cr, Fe, Mn and Ni content, with isolated samples showing elevated concentrations of Cd, Cu, Pb and Zn, mostly within the industrialized urban environment. The calculation of enrichment factors based on the national background concentrations provided limited insights into the origin of geogenic metals. Overall, this study highlighted the need for a more holistic approach to assess the impact of the geological background and anthropogenic activities on river waters and sediments.

Impact of drinking water hardness on carotid atherosclerosis and arterial stiffness: Insights from the "Corinthia" study.

BACKGROUND: Several investigations have highlighted the role of water quality in cardiovascular health. In the present study, we have investigated the effects of drinking water hardness on atherosclerotic burden in carotid arteries and arterial stiffness. METHODS: "Corinthia" study was conducted in the homonym region in Greece from 2015 to 2017. Carotid atherosclerosis was assessed by intima-media thickness (IMT). Pulse wave velocity (PWV) was used to evaluate arterial stiffness. Tap-water samples were collected from the study area and analyzed for a variety of elements, as well as pH and total hardness. RESULTS: Individuals living in lower drinking water hardness areas (Area 1) versus individuals living in higher water hardness areas (Area 2) had lower max IMT (p = 0.004) and were less susceptible to carotid plaque formation (p = 0.004). Interestingly, individuals over 65 years from Area 1 had lower mean IMT, max IMT, and less plaque formation (p < 0.001 for all). The mean value of PWV in the overall study population was below the 10 m/s cutoff, which defines arterial stiffness (9.15 ± 2.79 m/s). Nevertheless, a marginally higher rate of vascular stiffening was noted in Area 2 vs. Area 1 (16.2% and 12.8%, respectively, p = 0.048). CONCLUSIONS: According to this cross-sectional study's findings, a positive association between extra hard water and carotid atherosclerotic burden was found. However, the association with arterial stiffness is unclear and should be investigated further.

Do humans take good care of their offspring as animals do ! The Lavreotiki and Lavrion 'sagas', Hellenic Republic-Part 1: Historical outline and mapping of lead contamination.

The Lavreotiki-Lavrion area, situated in the south-eastern tip of mainland Hellas, has one of the longest mining, ore beneficiation and smelting legacies worldwide. With a history of over 5000 years of argentiferous Pb-Zn ore exploitation, Lavrion is a place that shaped human civilisation by being a major wealth producing centre of the ancient world but also represents one of the few significant industrial developments of the modern Hellenic Republic, since the second part of the 19th century. The long history of mining, ore beneficiation and smelting activities produced a vast amount of potentially toxic wastes. In the post-mining era of Lavrion, during the 1980's, cross-sectional epidemiological studies diagnosed a severe problem of blood-Pb poisoning in primary school-age children and highlighted the seriousness of environmental contamination on the health of the local population. The first part of this review deals with the contamination problem in the area with respect to Pb, and discusses the results of detailed geochemical and epidemiological studies, based on the source-pathway-receptor model. The second part of the review presents the holistic evaluation of the contamination hazard, the assessment of health-related risk to residents, and the socio-economical impact of the proposed remediation plan to the local community. The case of Lavrion-Lavreotiki area is a worldwide reference example of the environmental, economical, societal and health-related implications that the thousand-years long legacy of mineral resources exploitation has left behind.

Do humans take good care of their offspring as animals do ! the Lavreotiki and Lavrion 'sagas', Hellenic Republic-Part 2: hazard and risk assessment and remediation.

A number of geochemical and epidemiological studies verified that the Lavrion urban and suburban area is highly contaminated and has affected to a variable degree the health of the inhabitants, presented in the first part of review on the Lavrion 'sagas'. In the second part of this review, emphasis is given to the challenge environmental scientists faced in communicating the scientific results to environmental managers and the public and state officials in order for them to understand the benefits of prioritising public health over wealth. Imminent remediation actions have been developed and proposed in order to secure a healthier life for the local population. The proposed integrated environmental management scheme was based on the findings of hazard and health risk assessment. The aim was not only to remediate the contaminated land, but also to inform the local population and authorities regarding the environmental hazards that they were facing, and the necessary safety measures that should be taken. However, the proposed lifestyle changes were viewed with scepticism from all stakeholders. This paper seeks to provide some answers to questions related to the obstacles that have prevented the implementation of the proposed remediation plan on a large scale by reporting on risk perception and response to scientific evidence by the affected community in Lavrion. It also underlines the significant role of SEGH in linking applied environmental research with the public.

Estimating remobilization of potentially toxic elements in soil and road dust of an industrialized urban environment.

The mobility of potentially toxic elements (PTEs) is of paramount concern in urban settings, particularly those affected by industrial activities. Here, contaminated soils and road dusts of the medium-size, industrialized city of Volos, Central Greece, were subjected to single-step extractions (0.43 M HNO3 and 0.5 M HCl) and the modified BCR sequential extraction procedure. This approach will allow for a better understanding of the geochemical phase partitioning of PTEs and associated risks in urban environmental matrices. Based on single extraction procedures, Pb and Zn exhibited the highest remobilization potential. Of the non-residual phases, the reducible was the most important for Pb, and the oxidizable for Cu and Zn in both media. On the other hand, mobility of Ni, Cr, and Fe was low, as inferred by their dominance into the residual fraction. Interestingly, we found a significant increase of the residual fraction in the road dust samples compared to soils. Carbonate content and organic matter controlled the extractabilities of PTEs in the soil samples. By contrast, for the road dust, magnetic susceptibility exerted the main control on the geochemical partitioning of PTEs. We suggest that anthropogenic particles emitted by heavy industries reside in the residual fraction of the SEP, raising concerns about the assessment of this fraction in terms of origin of PTEs and potential environmental risks. Conclusively, the application of sequential extraction procedures should be complemented with source identification of PTEs with the aim to better estimate the remobilization of PHEs in soil and road dust influenced by industrial emissions.

Lead removal from aqueous solutions by olive mill wastes derived biochar: Batch experiments and geochemical modelling.

In this study, lead removal from aqueous solutions using biochar derived from olive mill solid and liquid wastes has been investigated by applying batch experiments and geochemical modelling. The batch adsorption experiments included the assessment of several key parameters such as the contact time (kinetic), initial concentration (isotherm), pH, adsorbent dose, and the presence of competitive cations, whilst the geochemical modelling focused on the involved adsorption mechanisms using the PHREEQC code. The kinetic studies showed that lead adsorption is a relatively fast process, where intraparticle diffusion is the rate-limiting step. Biochar dose, solution pH and the presence of competitive ions significantly affected the Pb adsorption effectiveness by the biochar. Especially the higher Pb removal percentages were observed in mono-elemental solutions with high biochar dose at mildly acidic solution pH values. The maximum Pb adsorption capacity of biochar was estimated as 40.8 mg g-1 which is higher than various biochars derived from sludge, lignocellulosic and animal biomasses. On the other hand, the geochemical modelling employing the PHREEQC code showed that ion exchange and Pb precipitation are the main reactions controlling its removal from aqueous solutions, whilst surface complexation is insignificant, mainly due to the low surface functional groups on the used biochar.

Tracing the sources of bioaccessible metal(loid)s in urban environments: A multidisciplinary approach.

Understanding the links between sources of magnetic particles and bioaccessibility of metal(loids) in environmental sampling media is crucial for better evaluating human health risks, although relevant information in the scientific literature is scarce. Here, soil, road and house dust samples from a heavy industrial area in Greece were characterized in a multidisciplinary study combining magnetic measurements, SEM/EDS analyses, bioaccessibility measurements and Pb isotopic analyses of bioaccessible Pb. The oral and inhalable bioaccessible fractions of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were assessed by applying simulated gastric and lung solutions. SEM/EDS analysis revealed the abundant presence of anthropogenic Fe-containing spherules of industrial origin in all sampling media, often containing minor contents of Cr, Cu, Mn, Pb and Zn. The inhalation bioaccessibility (%) in all environmental compartments was higher than the oral one for most elements analyzed in the present study. Clear associations between magnetic susceptibility and bioaccessible amounts of most of analyzed elements were encountered for the soil and road dust. The isotopic analyses of bioaccessible Pb showed that there are significant differences in the isotopic ratios between total and bioaccessible Pb. We conclude that Pb solubilized by the simulated gastric and lung extractions is principally anthropogenic, representing a mixture of industrial Pb and Pb related to the past usage of leaded petrol. Low values of 206Pb/207Pb were accompanied by high bioaccessible contents of Cd, Pb and Zn indicating that anthropogenic (mostly industrial) sources exert influence on the bioaccessible forms of these metals. Coupling magnetic and bioaccessibility measurements with stable isotopic technique of bioaccessible Pb is more reliable for determining Pb and other metal sources with high oral and inhalation bioaccessibility.

Geochemical interactions in the trace element-soil-clay system of treated contaminated soils by Fe-rich clays.

Clays have been widely applied in contaminated soils in order to reduce the mobility of potentially toxic elements (PTEs), such as Pb, Zn and Cu. In the present study, three Fe-rich clays from Greece were selected as amendments of three contaminated soils with distinct physicochemical and mineralogical characteristics. The amendments consisted of palygorskite-rich (PCM), Fe-smectite-rich (SCM) and natural palygorskite/Fe-smectite-rich (MCM) clays. The changes induced in the environment of the soil-PTE-clay system were assessed by examining the water-labile fraction of Pb, Zn and Cu, as well as the bioaccessibility of Pb, in the contaminated soils. The initial water-leachable concentrations of PTEs in soil were within the range 1826-6160 µg/kg Pb, 152-645 µg/kg Cu and 370-4052 µg/kg Zn. All three Fe-rich clays exhibited high retention efficiency toward PTEs, following the order Pb (55-70%) > Zn (45-55%) > Cu (0-45%). The high reactive surface area of the clay particles acted as a substrate for the deposition of Fe-Al oxides with a concomitant removal of PTEs that were transported through the colloidal fraction. Furthermore, the decrease in relative bioaccessibility of Pb (5-10% compared to the control) suggests dissolution of primary clays followed by entrapment of the element in secondary Fe-rich precipitates. In conclusion, the use of Fe-rich clays as soil amendments may have a positive effect in reducing the environmentally significant PTE fraction in soils, especially when different clay phases coexist.