In situ monitoring (field screening) and assessment of lead and arsenic contaminants in the greater New Orleans area using a portable X-ray fluorescence analyser

Geochemical fingerprinting and magnetic susceptibility to unravel the heterogeneous composition of urban soils

The typically high heterogeneity of urban soil properties challenges their characterization and interpretation. The objective of this study was to investigate if proximally sensed volume-specific magnetic susceptibility and/or geochemical soil properties can uncover differences in anthropogenic, lithogenic and pedological contributions in, and between, urban soils. We also tested if volume-specific magnetic susceptibility can predict heavy metal enrichment. Data on 29 soil properties of 103 soil horizons from 16 soils from Ghent, Belgium, were analyzed by factor analysis. A correlation analysis, and in-depth analysis of five contrasting urban soils supplemented insights gained from the factor analysis. The factor analysis extracted four factors: 29.2 % of the soil property variability was attributed to fossil fuel combustion and industrial processes, with high (>0.80) loadings for S, organic carbon, magnetic susceptibility, and Zn. Furthermore, 26.0 % of the variability was linked to parent material differences, with high loadings (>0.80) for K, Rb and Ti. In absence of geogenic carbonates, increased soil alkalinity due to anthropogenic input of CaCO₃ explained 17.0 % of the variability. Lastly, 4.7 % of the variability resulted from variable Zr contents by local geology. Elemental analysis by XRF, possibly combined with magnetic susceptibility measurements, helped to explain lateral or vertical differences related to (1) the nature of anthropogenic influence, for instance burning (e.g., by the S and Zn content) or the incorporation of building rubble (e.g., by the Ca content); (2) the particle size distribution (e.g., by the K, Rb or Ti content); (3) lithology (e.g., by the Zr content); or (4) pedology, such as organic matter build-up (e.g., by the S content) or leaching of alkalis (e.g., by the Ca content). Even though artifacts and soil translocation were common in the studied soils, volume-specific soil magnetic susceptibility measured on fine earth predicted the total heavy metal pollution loading index well (Pearson correlation = 0.85).

X-ray fluorescence spectrometry for environmental analysis: Basic principles, instrumentation, applications and recent trends

In recent years, the conceptual advancement on green analytical chemistry (GAC) has moved in parallel with efforts to incorporate new screening or quantitative low-cost analytical tools to solve analytical problems. In this sense, the role of solid state techniques that allow the non-invasive analysis (or with a minimum sample treatment) of solid samples cannot be neglected. This review describes the basic principles, instrumentation and advances in the application of X-ray fluorescence instrumentation to the environmental sciences research topics, published between 2006 and 2020. Obviously, and because of the enormous number of works that can be found in the literature, it is not possible to exhaustively cover all published articles and the diversity of topics related to the environment in which a solid state technique like XRF has been applied successfully. It is a question of making a compilation of the instrumentation in use, the significant advances in XRF spectrometry and sample treatment strategies to highlight the potential of its implementation for environmental assessment.

In situ investigation of heavy metals at trace concentrations in greenhouse soils via portable X-ray fluorescence spectroscopy

Soil pollution by heavy metals (HMs) has rapidly become a major threat to vegetable security. Nearly all cultivated soils are at risk of metal accumulation, and greenhouse soils are among the most heavily impacted soils. In this study, a rapid assessment of HMs at trace concentrations was conducted via portable X-ray fluorescence (PXRF) spectroscopy in Shouguang, China. Measurements were made via PXRF under in situ, ex situ and sieved conditions and by inductively coupled plasma mass spectrometry (ICP-MS) after acid digestion. The performance of each PXRF measure relative to the ICP-MS method was assessed by linear regression. Redundancy analysis was performed to quantify the proportion of explained variability between the PXRF and ICP-MS data. Evaluation of the possible sources of HMs and their potential risks was then conducted by multivariate analysis. The results showed that the PXRF data were closely correlated with ICP-MS quantification for Cu, Mn and Zn, whereas no significant correlations were found for As, Ni and Pb. The uncertainties of PXRF measurement derived from soil heterogeneity accounted for 20.02% of total variability and those from moisture and particle size accounted for 20.15%. The geo-accumulation index (I_geo) indicated that the greenhouse soils were potentially contaminated by Cu and Zn (I_geo > 0), which can be attributed to anthropogenic activities. Overall, PXRF spectroscopy is promising as a rapid and nondestructive in situ technique for assessing the potential risks of HMs at trace concentrations in greenhouse soils.

Chemical contamination of soils in the New York City area following Hurricane Sandy

This paper presents a unique data set of lead, arsenic, polychlorinated biphenyl (PCB), and polycyclic aromatic hydrocarbon (PAH) concentrations in soil samples collected from the metropolitan New York City area in the aftermath of Hurricane Sandy. Initial samples were collected by citizen scientists recruited via social media, a relatively unusual approach for a sample collection project. Participants in the affected areas collected 63 usable samples from basements, gardens, roads, and beaches. Results indicate high levels of arsenic, lead, PCBs, and PAHs in an area approximately 800 feet south of the United States Environmental Protection Agency (US EPA) Superfund site at Newtown Creek. A location adjacent to the Gowanus Canal, another Superfund site, was found to have high PCB concentrations. Areas of high PAH contamination tended to be near high traffic areas or next to sites of known contamination. While contamination as a direct result of Hurricane Sandy cannot be demonstrated conclusively, the presence of high levels of contamination close to known contamination sites, evidence for co-contamination, and decrease in number of samples containing measureable amounts of semi-volatile compounds from samples collected at similar locations 9 months after the storm suggest that contaminated particles may have migrated to residential areas as a result of flooding.

A comparative evaluation of semen parameters in pre- and post-Hurricane Katrina human population

A natural disaster leading to accumulation of environmental contaminants may have substantial effects on the male reproductive system. Our aim was to compare and assess semen parameters in a normospermic population residing in the Southern Louisiana, USA area pre- and post-Hurricane Katrina. We retrospectively evaluated semen analyses data (n = 3452) of 1855 patients who attended the Tulane University Andrology/Fertility Clinic between 1999 and 2013. The study inclusion criteria were men whose semen analyses showed ≥ 1.5 ml volume; ≥15 million ml^-1 sperm concentration; ≥39 million total sperm count; ≥40% motility; >30% morphology, with an abstinence interval of 2–7 days. After the inclusion criteria applied to the population, 367 normospermic patients were included in the study. Descriptive statistics and group-based analyses were performed to interpret the differences between the pre-Katrina (Group 1, 1999–2005) and the post-Katrina (Group 2, 2006–2013) populations. There were significant differences in motility, morphology, number of white blood cell, immature germ cell count, pH and presence of sperm agglutination, but surprisingly there were no significant differences in sperm count between the two populations. This long-term comparative analysis further documents that a major natural disaster with its accompanied environmental issues can influence certain semen parameters (e.g., motility and morphology) and, by extension, fertility potential of the population of such areas.

Metals analysis of agricultural soils via portable X-ray fluorescence spectrometry

To assess the applicability of portable X-ray fluorescence (PXRF) spectrometry for metals analysis, total concentrations of As, Pb, Cu, and Zn in 47 agricultural soils were determined using in situ PXRF analysis, ex situ PXRF analysis, and conventional laboratory analysis. The correlation regression parameters of PXRF data with the data of conventional analysis were significantly improved upon going from in situ to ex situ, indicating that improvement of the ex situ PXRF data quality was achieved thorough sample preparation. Use of PXRF in situ was inferior to other analyses, especially when attempting to quantify relatively low levels of metals in agricultural soils. A high degree of linearity and similar spatial distribution existed between ex situ PXRF and laboratory analysis, suggesting that PXRF can be used in rapid detection or screening of agricultural soils, but is best followed with additional sample preparation ex situ and laboratory confirmation.

Pollution distribution of heavy metals in surface soil at an informal electronic-waste recycling site

We studied distribution of heavy metals [lead (Pb), copper (Cu) and zinc (Zn)] in surface soil at an electronic-waste (e-waste) recycling workshop near Metro Manila in the Philippines to evaluate the pollution size (spot size, small area or the entire workshop), as well as to assess heavy metal transport into the surrounding soil environment. On-site length-of-stride-scale (~70 cm) measurements were performed at each surface soil point using field-portable X-ray fluorescence (FP-XRF). The surface soil at the e-waste recycling workshop was polluted with Cu, Zn and Pb, which were distributed discretely in surface soil. The site was divided into five areas based on the distance from an entrance gate (y-axis) of the e-waste recycling workshop. The three heavy metals showed similar concentration gradients in the y-axis direction. Zn, Pb and Cu concentrations were estimated to decrease to half of their maximum concentrations at ~3, 7 and 7 m from the pollution spot, respectively, inside the informal e-waste recycling workshop. Distance from an entrance may play an important role in heavy metal transport at the soil surface. Using on-site FP-XRF, we evaluated the metal ratio to characterise pollution features of the solid surface. Variability analysis of heavy metals revealed vanishing surficial autocorrelation over metre ranges. Also, the possibility of concentration prediction at unmeasured points using geostatistical kriging was evaluated, and heavy metals had a relative "small" pollution scales and remained inside the original workshop compared with toxic organohalogen compounds. Thus, exposure to heavy metals may directly influence the health of e-waste workers at the original site rather than the surrounding habitat and environmental media.

Analysis of U.S. soil lead (Pb) studies from 1970 to 2012

Although lead (Pb) emissions to the air have substantially decreased in the United States since the phase-out of leaded gasoline by 1995, amounts of lead in some soils remain elevated. Lead concentrations in residential and recreational soils are of concern because health effects have been associated with Pb exposure. Elevated soil Pb is especially harmful to young children due to their higher likelihood of soil ingestion. The purpose of this study is to create a comprehensive compilation of U.S. soil Pb data published from 1970 through 2012 as well as to analyze the collected data to reveal spatial and/or temporal soil Pb trends in the U.S. over the past 40 years. A total of 84 soil Pb studies across 62 U.S. cities were evaluated. Median soil Pb values from the studies were analyzed with respect to year of sampling, residential location type (e.g., urban, suburban), and population density. In aggregate, there was no statistically significant correlation between year and median soil Pb; however, within single cities, soil Pb generally declined over time. Our analysis shows that soil Pb quantities in city centers were generally highest and declined towards the suburbs and exurbs of the city. In addition, there was a statistically significant, positive relationship between median soil Pb and population density. In general, the trends examined here align with previously reported conclusions that soil Pb levels are higher in larger urban areas and Pb tends to remain in soil for long periods of time.

Characterization of soils from an industrial complex contaminated with elemental mercury

Historical use of liquid elemental mercury (Hg(0)l) at the Y-12 National Security Complex in Oak Ridge, TN, USA, resulted in large deposits of Hg(0)l in the soils. The fate and distribution of the spilled Hg(0) are not well characterized. In this study we evaluated analytical tools for characterizing the speciation of Hg in the contaminated soils and then used the analytical techniques to examine the speciation of Hg in two soil cores collected at the site. These include x-ray fluorescence (XRF), soil Hg(0) headspace analysis, and total Hg determination by acid digestion coupled with cold vapor atomic absorption (HgT). XRF was not found to be suitable for evaluating Hg concentrations in heterogeneous soils containing low concentration of Hg or Hg(0) because Hg concentrations determined using this method were lower than those determined by HgT analysis and the XRF detection limit is 20 mg/kg. Hg(0)g headspace analysis coupled with HgT measurements yielded good results for examining the presence of Hg(0)l in soils and the speciation of Hg. The two soil cores are highly heterogeneous in both the depth and extent of Hg contamination, with Hg concentrations ranging from 0.05 to 8400mg/kg. In the first core, Hg(0)l was distributed throughout the 3.2m depth, whereas the second core, from a location 12m away, contained Hg(0)l in a 0.3m zone only. Sequential extractions showed organically associated Hg dominant at depths with low Hg concentration. Soil from the zone of groundwater saturation showed reducing conditions and the Hg is likely present as Hg-sulfide species. At this depth, lateral Hg transport in the groundwater may be a source of Hg detected in the soil at the deeper soil depths. Overall, characterization of soils containing Hg(0)l is difficult because of the heterogeneous distribution of Hg within the soils. This is exacerbated in industrial facilities where fill materials make up much of the soils and historical and continued reworking of the subsurface has remobilized the Hg.

Environmental lead after Hurricane Katrina: implications for future populations

BACKGROUND

As a result of Hurricane Katrina, > 100,000 homes were destroyed or damaged and a significant amount of sediment was deposited throughout the city of New Orleans, Louisiana. Researchers have identified the potential for increased lead hazards from environmental lead contamination of soils.

OBJECTIVES

We assessed the distribution of residential soil and dust lead 2 years poststorm and compared soil lead before and after the storm.

METHODS

We conducted a cross-sectional study in New Orleans in which households were selected by stratified random sampling. A standard residential questionnaire was administered, and lead testing was performed for both the interior and exterior of homes. Logistic regression was used to identify significant predictors of interior and exterior lead levels in excess of allowable levels.

RESULTS

One hundred nine households were enrolled; 61% had at least one lead measurement above federal standards. Of homes with bare soil, 47% had elevated lead and 27% had levels exceeding 1,200 ppm. Housing age was associated with soil lead, and housing age and soil lead were associated with interior lead. Race, income, and ownership status were not significantly associated with either interior or exterior lead levels. The median soil lead level of 560 ppm was significantly higher than the median level of samples collected before Hurricane Katrina.

CONCLUSIONS

The high prevalence (61%) of lead above recommended levels in soil and dust samples in and around residences raises concern about potential health risks to the New Orleans population, most notably children. Steps should be taken to mitigate the risk of exposure to lead-contaminated soil and dust. Further research is needed to quantify the possible contribution of reconstruction activities to environmental lead levels.