Extractability and mobility of mercury from agricultural soils surrounding industrial and mining contaminated areas

This study focussed on a comparison of the extractability of mercury in soils with two different contamination sources (a chlor-alkali plant and mining activities) and on the evaluation of the influence of specific soil properties on the behaviour of the contaminant. The method applied here did not target the identification of individual species, but instead provided information concerning the mobility of mercury species in soil. Mercury fractions were classified as mobile, semi-mobile and non-mobile. The fractionation study revealed that in all samples mercury was mainly present in the semi-mobile phase (between 63 and 97%). The highest mercury mobility (2.7 mg kg-1) was found in soils from the industrial area. Mining soils exhibited higher percentage of non-mobile mercury, up to 35%, due to their elevated sulfur content. Results of factor analysis indicate that the presence of mercury in the mobile phase could be related to manganese and aluminum soil contents. A positive relation between mercury in the semi-mobile fraction and the aluminium content was also observed. By contrary, organic matter and sulfur contents contributed to mercury retention in the soil matrix reducing the mobility of the metal. Despite known limitations of sequential extraction procedures, the methodology applied in this study for the fractionation of mercury in contaminated soil samples provided relevant information on mercury's relative mobility

The Production of Mammary Carcinomas in Rats by 9,10-Dimethyl-1,2-Benzanthracene and its Relationship to the Oestrous Cycle

Sprague-Dawley rats aged 50 days were given single oral doses of the carcinogen, DMBA

An online survey of Australian physicians reported practice with the off-label use of nebulised frusemide

BACKGROUND: Off-label prescribing is common in palliative care. Despite inconsistent reports of the benefit of nebulised frusemide for breathlessness, its use continues to be reported. METHODS: An online survey was emailed to 249 members of the Australian and New Zealand Society of Palliative Medicine to estimate the use of nebulised frusemide for breathlessness by Australian physicians involved in palliative care in the previous 12 months. RESULTS: There were 52/249 (21%) respondents to the survey. The majority (44/52; 85%) had not prescribed nebulised frusemide in the previous 12 months. The most common (18/44; 43%) reason for not prescribing nebulised frusemide was a belief that there was not enough evidence to support its use. Whilst only a few respondents (8/52; 15%) reported having used nebulised frusemide, all that had used it thought there was at least some benefit in relieving breathlessness. CONCLUSION: This report adds to the series of case studies reporting some benefit from nebulised frusemide in relieving breathlessnes

Oral bioaccessibility tests to measure potentially toxic elements in inhalable particulate matter collected during routine air quality monitoring

The simplified bioaccessibility extraction test (SBET) and the stomach phase of the unified bioaccessibility method (UBM) have been modified for use in assessing the bioaccessibility of potentially toxic elements in samples of PM10 collected during routine air quality monitoring. Arsenic, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were measured by inductively coupled plasma mass spectrometry in extracts of synthetic PM samples prepared by loading candidate soil reference material BGS102 onto TX40 (Teflon-coated borosilicate) filters widely used in standard commercial tapered element oscillating microbalance/filter dynamics measurement system (FDMS) ambient particulate monitors. Analysis of blanks revealed two important sources of contamination that had to be controlled in order to achieve reproducible results. The syringe filters used in the SBET released Cu and Zn into sample extracts during filtration and had to be washed with 80 mL of 0.4 M glycine at pH 1.5 immediately prior to use, whilst the FDMS filters used to collect PM10 were found to contain sufficient extractable Zn (ca. 3 μg per filter) to almost double the concentration released by the soil. The latter is a consequence of the use of Zn in filter manufacture and so could not be eliminated, but was successfully overcome by means of blank-subtraction. A ten-fold miniaturisation of the SBET and six-fold miniaturisation of the UBM allowed 0.1 g samples to be processed, with analyte recoveries generally within ±10% of those obtained when the conventional procedures were used. Comparison between results obtained when the modified procedures were applied to soil alone, and when soil was loaded onto FDMS filters, indicated that the presence of the filter had no effect on extraction efficiency, except for Fe, provided blank-correction was performed. Results obtained for As, Cd and Pb when the modified UBM was applied to BGS102 on FDMS filters were 4.40 ± 0.04, 0.224 ± 0.002 and 17.3 ± 0.8 mg kg-1, respectively (n = 3), all within recommended ranges

A novel two-step sequential bioaccessibility test for potentially toxic elements in inhaled particulate matter transported into the gastrointestinal tract by mucociliary clearance

A novel two-step sequential extraction has been developed to assess the bioaccessibility of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn in airborne particulate matter following inhalation and transport into the human gastrointestinal tract by mucociliary clearance. A new artificial mucus fluid (AMF) was used to determine the bioaccessible potentially toxic element (PTE) fraction in the upper airways, in sequence with the simplified bioaccessibility extraction test (SBET) or the stomach phase of the unified bioaccessibility method (gastric fluid only) (UBMG). Filter dynamic measurement system TX40 filters smeared with soil reference material (BGS RM 102) were used as test samples. Analysis was performed by ICP-MS. Comparison between results obtained for soil alone and when the soil was supported on TX40 filters indicated that the presence of the substrate did not affect the extraction efficiency, although a large Zn blank was detected. The sequential AMF→SBET extraction liberated similar amounts of Fe, Mn, Ni and Zn to the SBET alone; but significantly less Cd; and significantly more As, Cr, Cu and Pb. The sequential AMF→UBMG extraction liberated similar amounts of Cd, Cr, Mn and Zn to the UBMG alone, but significantly less As, Fe and Ni; and significantly more Cu and Pb. Enhanced extractability was due to the greater quantities of exchangeable ions and complexing agents present. Adoption of a two-step sequential extraction (AMF followed by either the SBET or the UBMG) is recommended because it is more representative of biological conditions and avoids overestimation or underestimation of bioaccessible PTE concentrations

Overview and challenges of mercury fractionation and speciation in soils

Analytical procedures to assess mercury speciation in soils still lack consensus. This article presents an overview of the mercury fractionation and speciation procedures used in soils. Mercury fractionation is the most common approach despite the operational definition of the fractions. Application of single extraction procedures that target the water-soluble, exchangeable and acid-soluble fractions and the application of EPA method 3200 for mercury sequential extraction are examined in soils with different physicochemical characteristics. A step forward in mercury speciation is thermo-desorption, a useful tool to rapidly obtain needed information about contaminated soils. The advantages and limitations of these procedures are compared; the importance of soils’ physicochemical characteristics highlighted. Criteria to be considered when choosing a suitable method are given - assessing total mercury concentration, soil physicochemical characteristics, environmental conditions, and legislation. It is recommended that the interpretation of results is done wisely, to correctly support decisions concerning intervention strategies at contaminated sites

Atomic spectrometry update : a review of advances in environmental analysis

This is the 31st annual review of the application of atomic spectrometry to the chemical analysis of environmental samples. This update refers to papers published approximately between August 2014 and July 2015 and continues the series of Atomic Spectrometry Updates (ASUs) in Environmental Analysis that should be read in conjunction with other related ASUs in the series, namely: clinical and biological materials, foods and beverages; advances in atomic spectrometry and related techniques; elemental speciation; X-ray spectrometry; and metals, chemicals and functional materials. In the field of air analysis, highlights within this review period included: the development of a new laser fluorescence instrument for the ultratrace determination of mercury vapour; single particle ICP-MS studies and the coupling of elemental analysers to mass spectrometers for the improved characterisation of carbonaceous aerosols. In the arena of water analysis, methods continue to be developed: for the extraction and preconcentration of elements, As, Cr, Hg and Sb species and determination of elemental constituents in colloidal and NP fractions. Emerging elements of interest include Gd derived from MRI agents discharged at low level from medical facilities in water courses. Instrumental developments reported included the use of MC-ICP-MS for isotopic tracer studies and a review of TXRF techniques and associated preconcentration procedures for trace element analysis. In the period covered by this update several articles have explored the analysis of soil extracts for geochemical prospecting. There has been widening interest in the use of CS-AAS and in the application of techniques capable of direct sample analysis such as slurry sampling ETAAS and ETV-ICP-AES. Portable XRF instrumentation is now being used in many disciplines to quantify trace elements in soils – bringing a need for better transfer of analytical knowledge to non-specialist users – and the growing use of portable XRF in proximal sensing is also noteworthy. Recent research indicates that geological applications still drive many of the instrumental and methodological advances in LA-ICP-MS. Fundamental studies continued to shed light on the processes involved and hence ways of improving the analysis of laser-produced aerosols and to minimise matrix and fractionation effects. A new technique LA-DOF-MS (distance of flight) was described. The utility of LIBS and portable XRF for in situ survey work continues to show promise but issues such as appropriate calibration regimes and data processing protocols will still need to be addressed

Work and Career Experiences of Men from Families without College Experience

A dearth of research exists exploring the career and work development of adult men and the influence of family-of-origin on that development. In this qualitative study, the researchers used a phenomenological approach to examine the career and work experiences of men whose parents have no education beyond high school and the influences of family on these experiences. We describe five constituents: (a) what work is like; (b) preparation/education; (c) who or what influenced them; (d) how to act at work; and (e) challenges/opportunities/choices; and one essence: mottos from father, which articulate the meaning of the experience of work and career and the family influence on the experience. In conclusion, we provide implications for counselors working with adult men whose parents lack post-secondary education

Fractionation and ecotoxicological implication of potentially toxic metals in sediments of three urban rivers and the Lagos Lagoon, Nigeria, West Africa

The potential environmental impact of sediment-bound Cd, Cr, Cu, Pb and Zn in three trans-urban rivers in Lagos state and in the Lagos Lagoon was assessed by use of the modified Community Bureau of Reference (BCR) sequential extraction. The quality of the data was checked using BCR CRM 143R and BCR CRM 701. Good agreement was obtained between found and certified/indicative values. Of the rivers, the Odo-Iyaalaro, was generally the most contaminated and the Ibeshe the least. Higher concentrations of metals were generally found in the dry season compared to the wet season. Cadmium and Zn were released mostly in the acid exchangeable step of the sequential extraction, indicating that they have the greatest potential mobility and bioavailability of the analytes studied. Chromium and Cu were associated mainly with the reducible and oxidisable fractions, and Pb predominantly with the reducible and residual fractions. Sediments with the highest pseudototal analyte concentrations also released higher proportions of analytes earlier in the sequential extraction procedure. The study suggests that, during the dry season, potentially toxic metals (PTM) may accumulate in sediments in relatively labile forms that are released and can potentially be transported or bioaccumulate in the rainy season. Application of risk assessment codes and Hankanson potential risk indices indicated that Cd was the element of greatest concern in the Lagos Lagoon system. The study indicated that there is a need to strengthen environmental management and pollution control measures to reduce risk from PTM, but that even relatively simple strategies, such as seasonal restrictions on dredging and fishing, could be beneficial

Comparison of original and modified BCR sequential extraction procedures for the fractionation of copper, iron, lead, manganese and zinc in soils and sediments

This article describes a detailed comparison between the original BCR sequential extraction procedure, step 2 of which involves treatment with 0.1 mol l(-1) hydroxylammonium chloride at pH 2, and the revised BCR procedure (step 2: 0.5 mol l(-1) hydroxylammonium chloride at pH 1.5). An intermediate protocol was also evaluated in which 0.5 mol l(-1) hydroxylammonium chloride at pH 2 was used. The procedures were applied to five soil and sediment substrates: a sewage sludge-amended soil, two different industrially contaminated soils, a river sediment and an inter-tidal sediment. Extractable iron and manganese concentrations were measured to assess the effects of the procedural modifications on dissolution of the reducible matrix components. Trace elements copper, lead and zinc were also determined. Statistical analysis (two-tailed t-tests at 95% confidence interval) indicated that recovery of iron in step 2 was not markedly enhanced when the intermediate protocol was used. However, significantly greater amounts were isolated with the revised BCR scheme than with the original procedure. Copper behaved similarly to iron. Lead recoveries were increased by use of both modified protocols, with the greatest effect occurring for the revised BCR extraction. In contrast, manganese and zinc extraction did not vary markedly between procedures. The work indicates that the revised BCR sequential extraction provides better attack on the iron-based components of the reducible matrix for a wide range of soils and sediments. (C) 2002 Elsevier Science B.V. All rights reserved