scholarly journals Biogeochemistry of Household Dust Samples Collected from Private Homes of a Portuguese Industrial City

Geosciences ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 392
Author(s):  
Amélia P. Marinho-Reis ◽  
Cristiana Costa ◽  
Fernando Rocha ◽  
Mark Cave ◽  
Joanna Wragg ◽  
...  
Keyword(s):  
Trace Elements ◽  
Phase Distribution ◽  
Solid Phase ◽  
Hazard Quotient ◽  
Gastric Fluid ◽  
Indoor Dust ◽  
Multiple Discriminant Analysis ◽  
Household Dust ◽  
Calcium Carbonates ◽  
Oxide Component

The main objectives of the present study were to (i) investigate the effects of mineralogy and solid-phase distribution on element bioaccessibility and (ii) perform a risk assessment to calculate the risks to human health via the ingestion pathway. Multiple discriminant analysis showed that the dust chemistry discriminates between indoor and outdoor samples. The solid-phase distribution of the elements in indoor dust indicated that a large proportion of zinc, nickel, lead, copper, and cobalt is associated with an aluminum oxy-hydroxides component, formed by the weathering of aluminum silicates. This component, which seems to influence the mobility of many trace elements, was identified for a group of indoor dust samples that probably had a considerable contribution from outdoor dust. An iron oxide component consisted of the highest percentage of chromium, arsenic, antimony, and tin, indicating low mobility for these elements. The bioaccessible fraction in the stomach phase from the unified BARGE method was generally high in zinc, cadmium, and lead and low in nickel, cobalt, copper, chromium, and antimony. Unlike other potentially toxic elements, copper and nickel associated with aluminum oxy-hydroxides and calcium carbonates were not extracted by the stomach solutions. These trace elements possibly form stable complexes with gastric fluid constituents such as pepsin and amino acid. Lead had a hazard quotient >1, which indicates the risk of non-carcinogenic health effects, especially for children.

scholarly journals Children Health Risk Assessment of Metals in Total Suspended Particulate Matter (TSP) and PM1 in Kindergartens during Winter and Spring Seasons

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1096
Author(s):  
Anna Mainka
Keyword(s):  
Trace Elements ◽  
Health Risks ◽  
Hazard Quotient ◽  
Carcinogenic Risk ◽  
Indoor Dust ◽  
Exposure Pathways ◽  
Safe Level ◽  
Suspended Particulate ◽  
Total Suspended Particles ◽  
Single Trace

This study evaluates the health risks related to heavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sb, Se, Zn, and metalloid As) in the indoor dust samples of total suspended particles (TSP) and particles with diameter < 1 μm (PM1). The samples were collected during 5-day periods during the spring and winter seasons in the Upper Silesia region, Poland. The highest concentration among determined trace elements revealed Fe. The greatest concern expressed the concentration of carcinogenic Cd in PM1 (from 6.7 to 9.7 ng/m3), exceeding the permissible value 5 ng/m3 (for PM10). The carcinogenic and non-carcinogenic health risks were assessed for three exposure pathways (inhalation, ingestion, and dermal contact) for preschool children. None of the single trace elements obtained the Hazard Quotient Index (HQ > 1) or carcinogenic risks above the upper acceptable limit (1 × 10−4). However, the cumulative HQ values (SHQ) for three exposure pathways were greater than the safe level. The highest cumulative non-carcinogenic risk presented the TSP in rural kindergartens (2.0 × 10−4). In the same location as the TSP, the highest carcinogenic risk was also observed (9.1 × 10−4). High carcinogenic risks (>10−4) were found for the ingestion pathway of TSP inside urban and rural kindergartens and of PM1 in urban ones. A comparative evaluation shows that the health risks of trace elements in airborne particles in Polish kindergartens bring high risk.

Control of trace elements content in solid-phase extraction sorbent by x-ray fluorescence analysis

2020 ◽  
Author(s):  
E. V. Kochergina ◽  
A. O. Vagina ◽  
A. O. Taukin ◽  
A. V. Abramov ◽  
G. M. Bunkov ◽  
...  
Keyword(s):  
Trace Elements ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Fluorescence Analysis ◽  
Phase Extraction ◽  
X Ray

scholarly journals Human health impact assessment and temporal distribution of trace elements in Copșa Mică- Romania

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Katalin Bodor ◽  
Zsolt Bodor ◽  
Alexandru Szép ◽  
Róbert Szép
Keyword(s):  
Trace Elements ◽  
Hazard Quotient ◽  
Temporal Distribution ◽  
Health Impact ◽  
Temporal Variations ◽  
Carcinogenic Risk ◽  
Dermal Absorption ◽  
Safe Limit ◽  
Adults And Children ◽  
Mean Concentration

AbstractThe present study aims to analyze the temporal variations of PM10 and to assess the health risk indexes caused by trace elements from particulate matter (PM10) via inhalation, ingestion, and dermal absorption by adults and children in Copșa Mică (Romania) during 2009–2019. The results revealed a high multi-annual mean concentration of PM10 and trace elements. The analyzed air pollutants showed a decreasing trend during the studied years, therefore 44.11%, 43.48%, 36.07%, 16.02%, and 15.80% lower values were observed for As, Cd, Ni, PM10, and Pb, respectively, due to environmental regulations. The daily exceedance percentage of Pb and Cd was very high, representing 21.74% and 11.26%, followed by PM10 and As concentrations with 4.72% and 3.92%. The ratio between the trace element concentration measured in Copșa Mică and the country average was 2.46, 4.01, 2.44 and 10.52 times higher for As, Cd, Ni and Pb. The calculated Hazard Quotient values via inhalation were higher than the safe limit (1), which accounted 1.81, 3.89 and 4.52, for As, Cd and Ni, respectively, indicating that the trace elements might present a non-carcinogenic risk to both adults and children. Furthermore, the concentration of all studied trace elements in Copșa Mică showed cancer risk for adults via inhalation and dermal absorption as well.

scholarly journals Influence of Sodium Sulfate Addition on Iron Grain Growth during Carbothermic Roasting of Red Mud Samples with Different Basicity

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1571
Author(s):  
Pavel Grudinsky ◽  
Dmitry Zinoveev ◽  
Denis Pankratov ◽  
Artem Semenov ◽  
Maria Panova ◽  
...  
Keyword(s):  
Magnetic Separation ◽  
Grain Growth ◽  
Red Mud ◽  
Sodium Sulfate ◽  
Phase Distribution ◽  
Solid Phase ◽  
Alumina Production ◽  
Metallic Particles ◽  
Iron Phase ◽  
High Alkalinity

Red mud is an iron-containing waste of alumina production with high alkalinity. A promising approach for its recycling is solid-phase carbothermic roasting in the presence of special additives followed by magnetic separation. The crucial factor of the separation of the obtained iron metallic particles from gangue is sufficiently large iron grains. This study focuses on the influence of Na2SO4 addition on iron grain growth during carbothermic roasting of two red mud samples with different (CaO + MgO)/(SiO2 + Al2O3) ratio of 0.46 and 1.21, respectively. Iron phase distribution in the red mud and roasted samples were investigated in detail by Mössbauer spectroscopy method. Based on thermodynamic calculations and results of multifactorial experiments, the optimal conditions for the roasting of the red mud samples with (CaO + MgO)/(SiO2 + Al2O3) ratio of 0.46 and 1.21 were duration of 180 min with the addition of 13.65% Na2SO4 at 1150 °C and 1350 °C followed by magnetic separation that led to 97% and 83.91% of iron recovery, as well as 51.6% and 83.7% of iron grade, respectively. The mechanism of sodium sulfate effect on iron grain growth was proposed. The results pointed out that Na2SO4 addition is unfavorable for the red mud carbothermic roasting compared with other alkaline sulfur-free additives.

Trace elements in skin-contact clothes and migration to artificial sweat: Risk assessment of human dermal exposure

2016 ◽  
Vol 87 (6) ◽  
pp. 726-738 ◽  
Author(s):  
Joaquim Rovira ◽  
Martí Nadal ◽  
Marta Schuhmacher ◽  
José L Domingo
Keyword(s):  
Trace Elements ◽  
Health Risks ◽  
Hazard Quotient ◽  
Dermal Exposure ◽  
Environmental Scanning ◽  
Potential Health ◽  
Skin Contact ◽  
Artificial Sweat ◽  
High Concentrations ◽  
And Migration

The concentrations of a considerable number of trace elements (Ag, Al, As, B, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Sb, Sc, Se, Sm, Sn, Sr, Ti, Tl, V and Zn) were determined in various skin-contact clothes (T-shirts, blouses, socks, baby pajamas and bodies) from the Catalan (Spain) market. In addition, migration experiments with artificial acidic sweat were conducted in order to establish the migration rates of these elements. High levels of Zn (186–5749 mg/kg) were found in zinc pyrithione labeled T-shirts, while high concentrations of Sb and Cr were found in polyester and black polyamide fabrics, respectively. An environmental scanning electron microscope (ESEM) confirmed the presence of Ag and Ti particles and aggregates in several clothing items. The use of the ESEM complemented the results of the elemental analysis and migration experiments. Dermal exposure to trace elements was subsequently calculated, and the human health risks were assessed. Antimony showed the highest mean hazard quotient (HQ = 0.4) for male and female adults wearing polyester clothes; for one of the examined items (polyester T-shirt) the HQ was even above the safety limit (HQ > 1). Exposure to Sb from polyester textile could mean potential health risks in subpopulation groups who frequently wear these clothes, and for long time periods. The migration experiments with artificial sweat showed to be essential for establishing the exposure to trace elements through cloth with direct contact with skin.

Study of the kinetics of calcium molybdate leaching with sodium carbonate solutions

2021 ◽  
pp. 40-46
Author(s):  
Yu. V. Sokolova ◽  
◽  
E. V. Bogatyreva ◽  
Keyword(s):  
Solid Phase ◽  
Stable Phase ◽  
Calcium Carbonates ◽  
Calcium Molybdate ◽  
Carbonate Solutions ◽  
Efficient Recovery ◽  
Kinetic Mode ◽  
Kinetics Of ◽  
Soda Solution ◽  
Rate Controlling Step

Calcium molybdate forms powellite, it is produced as a result of oxidizing roasting of off-grade molybdenum sulphide concentrates and other molybdenum materials with calcium additives (calcium oxides and hydro xides, calcium chlorides) in air at the temperatures of 550–600 oC. Use of Na2CO3 solutions enables an efficient recovery of Мо from CaMoO4 and a quantitative removal of impurities. To determine the optimum conditions for this process, one would need data on CaMoO4 leaching within a broad range of Na2CO3 concentrations and at high temperature and one would need to analyze the composition of the solid phase and the kinetic parameters of the process, i.e. rate and rate-controlling step. The authors look at the CaMoO4 leaching kinetics in 1.0–2.5 mol/l Na2CO3 solutions at 60–90 oC. It was found that the process rate is dictated by the stirring intensity and tends to increase with a rising temperature and the reagent concentration rising in the range of 1.0–1.5 mol/l. A higher concentration of Na2CO3 has no effect on the reaction rate. An apparent reaction order was determined in the Na2CO3 concentration range of 1.0–1.5 mol/l. An equation is proposed for calculating the CaMoO4 dissolution rate for the Na2CO3 solution and the temperature of 80 oC. It was established that a kinetic mode of leaching takes place in the soda concentration range of 1.0–1.5 mol/l amid intensive stirring. It is demonstrated that, within the studied Na2CO3 concentration range, calcite СаСО3 is formed after vaterite, a less stable phase of calcite, with crystallization of double sodium-calcium carbonates Na2Са(CO3)2·nH2O (n = 0, 2, 5) occurring at the same time. With the concentration of soda being >1.5 mol/l, the process is controlled by internal diffusion. In this region, the leaching rate is independent of the Na2CO3 concentration. Formation of double carbonates is associated with an additional consumption of soda. Therefore, when using this system one should consider how CaMoO4 typically dissolves in Na2CO3 solutions. The presence of these compounds in the soda solution after molybdenum leaching may impact the recovery of Мо from the solution using the known techniques. It may also hinder the recirculation of sodium carbonates going for the second leaching cycle.

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