Higher heavy metal contamination indoors than outdoors during COVID-19 in Mexico City.

People spend most of their time indoors, especially during the coronavirus disease. Prolonged exposure to heavy metal-contaminated dust can be harmful to human health. The objectives of this study were to identify the contamination level in outdoor and indoor dust, compare contamination in both environments, and assess the human health risk. Two-hundred thirty-nine samples of dust were taken by Mexico City citizens in 38 homes on the weekends of May 2020. Heavy metal concentrations were measured through XRF. The contamination level was set using the contamination factor with a local and global background value, mixed linear models were used to identify indoor and outdoor differences, and USEPA human health risk methodology was used. Pb, Zn, and Cu had the highest contamination levels, followed by Sr and Mn, using both the local and global background values. The Pb, Zn, and Cu contamination was greater indoors, while higher Mn, Sr, and Fe were detected outdoors. According to the outdoor/indoor ratios, the main sources of Ca, Pb, Zn, and Cu must be indoors, while the main sources of Fe, Mn, Sr, Y, and Ti are outdoors. A human health risk was not detected, as the hazard index was lower than one. However, ailments can be developed due to exposure to Pb, Mn, and Fe in children (hazard index > 0.1). A higher risk due to Pb exposition was found indoors. Indoor environments in Mexico City were more contaminated by heavy metals and represented a higher risk to human health than outdoors during the pandemic isolation.

Assessing heavy metal pollution load index (PLI) in biomonitors and road dust from vehicular emission by magnetic properties modeling.

Vehicular traffic occupies a significant place among the sources of air pollution, due to population and urban growth that has led to an excessive increase in the vehicle fleet worldwide, and in Costa Rica as well. Vehicle emissions generate greenhouse gases (GHGs), particulate matter (PM), and heavy metals (HMs), due to combustion products from fossil-fuel engines, tire wear, and brake linings. HMs are important because they cannot be degraded or destroyed naturally; however, they can be diluted by physicochemical agents and be incorporated into trophic chains where they can be bioaccumulated causing significant negative effects on human well-being and ecological quality. This study aimed to assess the HM pollution load in biomonitors and road dust from vehicular emissions by chemical analyses and magnetic properties modeling. For this purpose, chemical and magnetic property analyses were carried out on samples of road dust and leaves of Cupressus lusitanica Mill. and Casuarina equisetifolia L., which were sampled during 2 different years in the Greater Metropolitan Area of Costa Rica known as GAM. Contamination factor (CF) and pollution load index (PLI) results showed significant metal pollution in some of the study sites. Contamination by the metals V, Cr, and Zn was most commonly present in the biomonitors, and for road dust, they were Cr, Zn, and Pb. The PLI estimates obtained with the validated support vector machine (SVM) magnetic properties models were consistent (sensitivity, specificity, and precision) with those obtained by chemical analysis, demonstrating the feasibility of this method for the identification of this index of contamination.

Heavy metals concentration, pollution indexes, and health risk assessment of urban road dust in the historical center of Havana, Cuba.

In recent years, the historical center of Old Havana has been under a serious restoration movement which could increase the heavy metal concentrations in street dusts and thus severely impact humans in the area. Therefore, the aim of this work is to study the heavy metal concentrations, pollution indexes, and health risk assessment of urban road dusts from the city in order to assess if this restoration movement is harmful to the citizens and visitors. Street road dust samples were collected at 33 stations for the determination of some heavy metals (Co, Ni, Cu, Zn, and Pb) concentrations using an X-ray fluorescence (XRF) instrument. The mean concentration values of the elements Co, Ni, Cu, Zn, and Pb were 7.0 mg.kg-1, 60.6 mg.kg-1, 73.6 mg.kg-1, 548.7 mg.kg-1, and 60.8 mg.kg-1, respectively. Zn and Pb showed higher values of the background. The study of the enrichment factor (EF), the pollution index (IP), and the integral pollution index (IPI) showed some stations with high values of contamination near construction places. Zn was identified as the major pollutant and correlated to the biggest construction places of the municipality at that moment. However, the hazard index (HI) and carcinogenic risk (CR) values do not show the risk of getting non-carcinogenic or carcinogenic diseases associated with the analyzed pollutants. Therefore, it was safely concluded that the big reconstruction movement does not represent a health problem.

Pollution characteristics, risk assessment, and source apportionment of potentially toxic elements in road dust at two industrial parks in Trinidad and Tobago, West Indies.

Potentially toxic elements can enter the environment through natural and anthropogenic processes, with the latter considered the primary contributor. Road dust samples from two industrial parks on the island of Trinidad were investigated for heavy metal content, and the pollution status, potential health risks, and source apportionment were evaluated. Samples were acid-digested and analysed by flame atomic absorption spectroscopy. The average levels of cadmium, chromium, copper, manganese, nickel, lead, and zinc in road dust at the Frederick Settlement Industrial Park were 1.14 µg/g, 15.13 µg/g, 66.42 µg/g, 768.49 µg/g, 37.95 µg/g, 55.90 µg/g, and 573.04 µg/g, respectively, while average concentrations at the O'Meara Industrial Park were 1.20 µg/g, 16.97 µg/g, 42.72 µg/g, 482.65 µg/g, 21.12 µg/g, 136.77 µg/g, and 358.70 µg/g, respectively. Contamination assessments evaluated both Fredrick Settlement and O'Meara as typically uncontaminated to moderately polluted, with the overall ecological risk deemed low at all locations. Hazard index values at all sampling areas were lower than 1, indicating no potential non-carcinogenic risks to children or adults, while the carcinogenic exposure risks for cadmium, chromium, and nickel were considered low. Principal component analysis and cluster analysis revealed two main sources of contamination for Fredrick Settlement, and three main sources for O'Meara. Based on the groupings obtained, the presence of potentially toxic elements was attributed primarily to specific anthropogenic activities within the industrial parks, with lesser contributions from vehicular-related sources.

Ambient particulate matter in Santiago, Chile: 1989-2018: A tale of two size fractions.

We have analyzed trends in ambient fine (PM2.5) and coarse (PM2.5-10) particulate matter in Santiago, Chile, for the last 30 years. PM2.5 has monotonously decreased between 67% and 72% at those sites. Trends varied between -2.0 and -2.7 (µg/m3/year) between 1989 and late 90's, and between -0.7 and -1.1 (µg/m3/year) afterwards. This slowing down is likely a consequence of fast increase of motor vehicles in the city, which have become a dominant source of ambient PM2.5. Annual ambient PM2.5 concentrations are still above 20 (µg/m3), so more regulation is needed to bring them down. Coarse particles have changed little in 30 years, decreasing between 0% and 12%; particle concentrations have evolved in a non-linear way: first increasing in 1989-1995, then decreasing until 2003, and with a flat trend afterwards. We ascribe these trends to a combination of a) public works implemented throughout the city, b) fugitive dust controls like street sweeping programs and emission offsets for PM10 and c) increasing numbers of motor vehicles in the city. Further initiatives are needed to curb down coarse particles as well. By considering interaction between trend and seasonality, we have found that ambient PM2.5 has monotonously decreased all year long at all monitoring sites with similar patterns; this is characteristic of a regional-scale pollution. For ambient PM2.5-10 trend and season have a more complex, site-specific interaction, suggesting local sources and site location in the basin are relevant in determining ambient concentrations of coarse particles. A limitation of this study is that no quantitative link between ambient concentrations trends and atmospheric emissions could be established with the analyses carried out. A strength of the study is the long period analyzed with measurements conducted with the same gravimetric methodology.

Distribution and health risk assessment of heavy metals in road dust from an industrial estate in Trinidad, West Indies.

Road dust from the Point Lisas Industrial Estate in Trinidad, West Indies was investigated to determine its heavy metal content and the associated health risks. The average concentrations of Cd, Cr, Cu, Mn, Ni, Pb and Zn were 3.44, 37.69, 58.16, 770.69, 35.61, 68.50 and 342.53 µg/g, respectively. The health risks due to exposure to heavy metals in road dust were assessed based on the US EPA's Health Risk Assessment Model for both carcinogenic and non-carcinogenic effects. The health risk assessment indicated that the ingestion pathway was the main exposure route to heavy metals from road dust; however, HI values suggested no potential health risks to both children and adults. The cancer risks for Cd, Cr and Ni were less than 10-6 and the resulting exposure was therefore considered low.

A scoping study of component-specific toxicity of mercury in urban road dusts from three international locations.

This scoping study presents an investigation of the total and bioaccessible mercury concentrations in road dust (RD) from three international urban sites, where a one-off sampling campaign was conducted at each. This was done to address the hypothesis that the matrix in which mercury is found influences its ability to become accessible to the body once inhaled. For that purpose, the samples were analysed for total and pulmonary bioaccessible mercury and the data compared to the chemical structure of individual particles by SEM. The results obtained from this study suggest that a high mercury content does not necessarily equate to high bioaccessibility, a phenomenon which could be ascribed to the chemical character of the individual particles. It was found that the Manchester samples contained more pulmonary soluble mercury species (as determined by elemental associations of Hg and Cl) in comparison to the other two samples, Curitiba, Brazil, and Johannesburg, South Africa. This finding ultimately underlines the necessity to conduct a site-specific in-depth analysis of RD, to determine the concentration, chemical structure and molecular speciation of the materials within the complex matrix of RD. Therefore, rather than simply assuming that higher bulk concentrations equate to more significant potential human health concerns, the leaching potential of the metal/element in its specific form (for example as a mineral) should be ascertained. The importance of individual particle behaviour in the determination of human health risk is therefore highlighted.

Levels, spatial distribution, risk assessment, and sources of environmental contamination vectored by road dust in Cienfuegos (Cuba) revealed by chemical and C and N stable isotope compositions.

Road dust is an indicator widely used when monitoring contamination and evaluating environmental and health risks in urban ecosystems. We conducted an exhaustive characterization of road dust samples coupling their chemical characteristics and stable isotope compositions (C and N) with the aim of evaluating the levels and spatial distribution of local contamination as well as to identify its main source(s) in the coastal city of Cienfuegos (Cuba). Results indicate that the concentrations of several elements (total nitrogen, S, Ca, V, Cu, Zn, Mo, Sn, Hg, and Pb) exceed the background values reported for both Cuban soils and the upper continental crust (UCC) and showed a high variability among the sampling sites. We show that road dust contamination in Cienfuegos induces high associated ecological risks. Among the studied elements, Cd and Hg are the major contributors to the environmental contamination in the city, mainly along busy roads and downtown. δ13C and δ15N, coupled to a multivariate statistical analysis, help associate the studied elements to several local sources of contamination: mineral matter derived from local soils, cement plant and related activities, road pavement alteration, power plant, road traffic, and resuspension of particulate organic matter (POM). Our results suggest that incorporating the chemical and isotope monitoring of road dust may help implement more effective environmental management measures in order to reduce their adverse impact on ecosystems and human health.

EVALUACIÓN DE METALES PESADOS ACUMULADOS EN POLVO VIAL EN TRES SECTORES DE LA CIUDAD DE VILLAVICENCIO, COLOMBIA / ASSESSMENT OF HEAVY METALS IN ACCUMULATED ROAD DUST IN THREE SECTORS OF THE CITY OF VILLAVICENCIO, COLOMBIA

La dinámica urbana derivada del crecimiento de las ciudades y de la demanda de la población en términos de servicios de transporte, de producción de alimentos, de bienes y servicios en general, son algunos de los responsables de la generación de factores contaminantes, donde uno de ellos es la presencia de metales pesados por acumulación en el polvo vial. En este sentido, el presente estudio tiene como finalidad evaluar la contaminación por presencia de metales pesados (Pb, Zn, Ni, Cu, Cr, y Cd) en el polvo de las vías de tres zonas de la ciudad de Villavicencio -Meta- (sector Anillo vial, sector Buque y sector Porvenir). Entre los resultados encontrados se tiene que la abundancia de metales por sector fue: sector Porvenir (SP), seguido del sector Anillo vial (SA) y sector Buque (SB). El estudio mostró que las concentraciones de metales pesados en el polvo vial están relacionadas con la dinámica de cada uno de ellos.

Urban dynamics derived from city growth and the population demands for transportation, food production, goods and services in general, are among the responsible on the generation of contaminating factors, where one of them is the presence of heavy metals in accumulated road dust. In this sense, the current study seeks to evaluate the pollution by presence of heavy metals (Pb, Zn, Ni, Cu, Cr, and Cd) in road dust from three sectors on Villavicencio -Meta- (sector Anillo vial sector, Buque sector and Porvenir sector). Among the obtained results, the metals abundance for each sector was as follows: Porvenir (SP), followed by sector Anillo vial (SA) and Buque (SB). The study showed that concentrations of heavy metals in road dust are related to the dynamics of each of these sectors.