Sergio Caroli

The Assessment of Reference Values for Elements in Human Biological Tissues and Fluids: A Systematic Review

Abstract A survey is presented of the rationale of and the operative procedures for the assessment of reference values of minor and trace elements in human blood (whether entire, plasma, or serum), urine, milk, hair, kidneys, liver, and lungs. Literature sources available on this subject matter have been scanned over the past 30 years and reference values have been critically and selectively reported. The need for further harmonization of strategies and better comparability of experimental data is emphasized.

Environmental risk of particulate and soluble platinum group elements released from gasoline and diesel engine catalytic converters

A comparison of platinum-group element (PGE) emission between gasoline and diesel engine catalytic converters is reported within this work. Whole raw exhaust fumes from four catalysts of three different types were examined during their useful lifetime, from fresh to 80,000 km. Two were gasoline engine catalysts (Pt-Pd-Rh and Pd-Rh), while the other two were diesel engine catalysts (Pt). Samples were collected following the 91441 EUDC driving cycle for light-duty vehicle testing, and the sample collection device used allowed differentiation between the particulate and soluble fractions, the latter being the most relevant from an environmental point of view. Analyses were performed by inductively coupled plasma-mass spectrometry (ICP-MS) (quadrupole and high resolution), and special attention was paid to the control of spectral interference, especially in the case of Pd and Rh. The results obtained show that, for fresh catalysts, the release of particulate PGE through car exhaust fumes does not follow any particular trend, with a wide range (one-two orders of magnitude) for the content of noble metals emitted. The samples collected from 30,000-80,000 km present a more homogeneous PGE release for all catalysts studied. A decrease of approximately one order of magnitude is observed with respect to the release from fresh catalysts, except in the case of the diesel engine catalyst, for which PGE emission continued to be higher than in the case of gasoline engines. The fraction of soluble PGE was found to represent less than 10% of the total amount released from fresh catalysts. For aged catalysts, the figures are significantly higher, especially for Pd and Rh. Particulate PGE can be considered as virtually biologically inert, while soluble PGE forms can represent an environmental risk due to their bioavailability, which leads them to accumulate in the environment.

Levels and risk assessment for humans and ecosystems of platinum-group elements in the airborne particles and road dust of some European cities

Traffic is the main source of platinum-group element (PGE) contamination in populated urban areas. There is increasing concern about the hazardous effects of these new pollutants for people and for other living organisms in these areas. Airborne and road dusts, as well as tree bark and grass samples were collected at locations in the European cities of Göteborg (Sweden), Madrid (Spain), Rome (Italy), Munich (Germany), Sheffield and London (UK). Today, in spite of the large number of parameters that can influence the airborne PGE content, the results obtained so far indicate significantly higher PGE levels at traffic sites compared with the rural or non-polluted zones that have been investigated (background levels). The average Pt content in airborne particles found in downtown Madrid, Göteborg and Rome is in the range 7.3-13.1 pg m(-3). The ring roads of these cities have values in the range 4.1-17.7 pg m(-3). In Munich, a lower Pt content was found in airborne particles (4.1 pg m(-3)). The same tendency has been noted for downtown Rh, with contents in the range 2.2-2.8 pg m(-3), and in the range 0.8-3.0 and 0.3 pg m(-3) for motorway margins in Munich. The combined results obtained using a wide-range airborne classifier (WRAC) collector and a PM-10 or virtual impactor show that Pt is associated with particles for a wide range of diameters. The smaller the particle size, the lower the Pt concentration. However, in particles <PM-10, some of the highest values correspond to the fraction <0.39 microm. Considering an average Pt content in all particles of approximately 15 pg m(-3), which is representative for all countries and environmental conditions, the tracheobronchial fraction represents approximately 10% and the alveolar fraction approximately 8% of the total particles suspended in air. However, from the environmental risk point of view, an exposure to PGEs in traffic-related ambient air is at least three orders of magnitude below the levels for which adverse health effects might theoretically occur (of approx. 100 ng m(-3)). Therefore, today inhalation exposure to PGEs from automotive catalysts does not seem to pose a direct health risk to the general population. Even though the data available today indicate no obvious health effects, there are still a number of aspects related to PGEs and catalysts that justify further research. First, continual monitoring of changes in PGE levels in air and road dust is warranted, to make sure that there is no dramatic increase from todays levels. Secondly, more detailed information on the chemical composition of the PGE-containing substances or complexes leaving the catalyst surface and the size distribution of the PGE-containing particles released during driving will facilitate a more in-depth human risk assessment.

Platinum-group elements: quantification in collected exhaust fumes and studies of catalyst surfaces

Automotive catalytic converters, in which Pt, Pd and Rh (platinum-group elements; PGEs) are the active components for eliminating several noxious components from exhaust fumes, have become the main source of environmental urban pollution by PGEs. This work reports on the catalyst morphology through changes in catalyst surface by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) and laser-induced breakdown spectrometry (LIBS) from fresh to aged catalytic converters. The distribution of these elements in the fresh catalysts analysed (Pt-Pd-Rh gasoline catalyst) is not uniform and occurs mainly in a longitudinal direction. This heterogeneity seems to be greater for Pt and Pd. PGEs released by the catalysts, fresh and aged 30,000 km, were studied in parallel. Whole raw exhaust fumes from four catalysts of three different types were also examined. Two of these were gasoline catalysts (Pt-Pd Rh and Pd-Rh) and the other two were diesel catalysts (Pt). Samples were collected following the 91,441 EUDC driving cycle for light-duty vehicle testing. The results show that at 0 km the samples collected first have the highest content of particulate PGEs and although the general tendency is for the release to decrease with increasing number of samples taken, exceptions are frequent. At 30,000 km the released PGEs in gasoline and diesel catalysts decreased significantly. For fresh gasoline catalysts the mean of the total amount released was approximately 100, 250 and 50 ng km(-1) for Pt, Pd and Rh, respectively. In diesel catalysts the Pt release varied in the range 400-800 ng km-1. After ageing the catalysts up to 30,000 km, the gasoline catalysts released amounts of Pt between 6 and 8 ng km(-1), Pd between 12 and 16 ng km(-1) and Rh between 3 and 12 ng km(-1). In diesel catalysts the Pt release varied in the range 108-150 ng km(-1). The soluble portion of PGEs in the HNO3 collector solution represented less than 5% of the total amount for fresh catalysts. For 30,000 km the total amount of soluble PGEs released was similar or slightly higher than for 0 km.

Assessment of reference values for elements in human hair of urban schoolboys

Hair samples of youngsters (3-15 years of age) from several urban areas of Rome were analyzed to determine the content of 19 minor and trace elements with the aim of assessing Reference Values (RVs). Thirteen essential elements were taken into account, Ca, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, P, Se, V and Zn. On the other hand, Al, As, Cd, Pb, Sr and Ti were also evaluated on the basis of their potential toxicity. Procedures were developed for the collection, storage and pre-analytical treatment of samples. Measurements were performed by inductively coupled plasma atomic emission spectrometry. Subgroups were formed according to age and sex. Significant differences were found for certain elements depending on age and sex. This was the case, e.g., for Ca which showed a mean value of 336 mg/kg for males and of 537 mg/kg for females. The sex-dependent pattern for this element was also apparent when the three age subgroups of 3-6, 7-10 and 11-15 years were compared. The overall RVs obtained (mg/kg) are as follows Al, 10.2; As, 0.09; Ca, 450; Cd, 0.23; Co, 0.67; Cr, 0.99; Cu, 22.1; Fe, 19.0; Mg, 28.0; Mn, 0.35; Mo, 0.43; Ni, 1.49; P, 195; Pb, 7.11; Se, 0.77; Sr, 1.20; Ti, 0.79; V, 1.22; and Zn 150.

Determination of essential and potentially toxic trace elements in honey by inductively coupled plasma-based techniques

The mandate assigned by the European Union to the Community Reference Laboratory for residues at the Istituto Superiore di Sanità covers, among other things, the assessment of trace elements in living animals as well as their products. To better protect the health of the consumer, this task aims in particular at harmonizing the procedures in use at the National Reference Laboratories (NRLs) for residues of the Member States for such determinations as well as at developing new approaches wherever the need arises. In this context an investigation was undertaken to appraise the average levels of a number of key elements in several types of honey with special regard to the influence of the various processing steps. Instrumental methods of election for the analysis of this matrix turned out to be inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) depending on the actual concentrations of the elements of interest. Dissolution of the samples for suitable presentation to the analytical systems could be easily achieved by gentle heating at ca. 50 degrees C, sonication and addition of high-purity water. The ranges ascertained are as follows (in ng g(-1)): As, <0.50-0.70; Cd, <0.50-0.74; Cr, 1.03-3.93; Cu, 144-216; Fe, 191-651; Mn, 223-580; Ni, 17-49; Pb, 3.20-186; Pt, <0.50; Sn, <4-27; V, 1.22-1.94; and Zn, 565-1144. As a rule, concentrations of elements in honey from different beehives were similar. A few exceptions were noted for As, Cu, Fe, Ni and Zn. On the other hand, although data obtained with different analytical approaches for the same types of honey and beehive were generally in good agreement, yet some inconsistencies occurred, as in the case of Cu in freshly collected, extracted and ripened honey, Ni in extracted honey and Fe in ripened honey. These could not be traced back to specific procedural facts; rather, they should be ascribed to the inherent heterogeneity of the raw material. The experience gained with this exploratory study will be exploited to set up wider surveys and to plan the preparation of a new certified reference material in a matrix of honey to the benefit of NRLs for residues.

On-line separation and preconcentration of chromium species in seawater

Abstract A study was undertaken to ascertain the analytical capabilities of combined HPLC-ICP-AES with ultrasonic nebulization or HPLC-ICP-MS systems to perform on-line separation of CrIII-CrVI and on-line preconcentration of CrVI. Tetrabutylammonium bromide was used as the ion-pair forming agent and a reverse phase C18 column was used for separation. By optimizing the conditions of separation and preconcentration as well as plasma parameters a method could be developed for the determination of CrIII and CrVI in seawater by HPLC-ICP-AES with ultrasonic nebulization. In this matrix detection limits (3σ criterion) turned out to be 4.6 ng/ml for CrIII and 3.7 ng/ml for CrVI, while the RSD is 2%–3% at the level of 100 ng/ml Cr. As the preconcentration of CrVI is regarded, the detection limit of ICP-AES depends, among others, on the sample volume loaded onto the column. It resulted to be 0.20 ng/ml for an initial volume of 2 ml, while the RSD at 10 ng/ml CrVI was ± 3.8%. On the other hand, the high salinity of seawater and C content of the separation eluent pose serious problems with ICP-MS detection. In fact, in this matrix only CrVI preconcentration was achieved with a detection limit of 0.12 ng/ml for CrVI (initial volume 2 ml). Due to isobaric interferences, the isotope at mass 50 (relative abundance 4.31%) was preferred.

Assessment of exposure to platinum-group metals in urban children ☆

Abstract Catalytic converters for automotive traction raise some concern for human health and the environment, due to the release of Pd, Pt and Rh (Pt-Group Metals, PGMs). In fact, the thermal and mechanical conditions under which such devices work (including abrasion effects and hot-temperature chemical reactions with oil fumes) can cause significant release of the PGMs to the environment and eventually affect human health. A pilot investigation was performed to assess the exposure to these metals of 310 schoolchildren aged between 6 and 10 years from the urban and suburban area of Rome. All determinations were performed by high-resolution magnetic-sector inductively-coupled plasma-mass spectrometry after UV irradiation of the samples. The mean concentration values of these metals in urine were found to be (in ng/g creatinine) 7.5±5.4 for Pd, 0.9±1.1 for Pt and 8.5±8.0 for Rh. Urine concentrations of Pd and Rh (but not Pt) were found to be strongly associated with traffic density in the area of residence.

On-line preconcentration and determination of trace elements by flow injection-inductively coupled plasma atomic emission spectrometry

Abstract A study was made of the capabilities of iminodiacetic acid/ethylcellulose (IDAEC) to serve as the chelating resin for preconcentrating trace elements together with a computer-assisted on-line flow injection analysis-inductively coupled plasma atomic emission spectrometry technique. The system was tested with a few analytes of particular clinical and environmental importance (Cd, Co, Cu and Pb) in matrices such as water, sea water and urine. The performance of IDAEC resin was compared with that of carboxymethylated polyethyleneimine-polymethylenepolyphenylene isocyanate (CPPI) and Chelex 100 with regard to enrichment factor, analytical throughput and recovery. With several obvious advantages over the batch procedure, the on-line mode improved the detection power by one to two orders of magnitude and allowed twelve samples per hour to be treated. IDAEC appears to be the most convenient resin in terms of efficiency and long-term performance.

Evaluation of the environmental contamination at an abandoned mining site

This paper reports the preliminary findings of an environmental survey carried out at an abandoned mining site. The wastes were stored in dumps with poor release control. The mining site had been active for over a century and was mostly exploited for its stibnite mineral. Quantitative analyses were performed on wastes, groundwater, surface water and air. Elements of concern were As, Cd, Hg, Pb, Sb, Sn and Zn. The results of tailing determinations indicated that Pb concentration remains almost constant in samples taken at various depths and that As and Hg levels are quite similar. Leaching tests demonstrated that element release was fairly low. With regard to element concentrations in surface water, particular attention should be given to As and Sb levels in the river and As concentrations in the pond. The high levels of As, Hg, Pb and Sb reported in tailings and groundwater may depend on both the presence of a geochemical aureole with elevated average background levels, and on the enrichment of metals in the stored tailings, due to processing. Among the airborne metal levels, the Hg concentration deserves attention. When considering element levels reported in solid and liquid matrices, particular emphasis should be given to As, Hg, Pb and Sb, since these are known to be long-lasting environmental pollutants that are toxic to most forms of life. They are also worth nothing as the disused mine is only a few km from the nearest town and close to areas used for agriculture and animal breeding. Exposure to the toxic agents can also occur for those workers still employed in the area near the mining site; this risk needs an adequate assessment.