Beatrice Bocca

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.

Trace and major elements in whole blood, serum, cerebrospinal fluid and urine of patients with Parkinson's disease.

Summary.Quantifications of Al, Ca, Cu, Fe, Mg, Mn, Si and Zn were performed in urine, serum, blood and cerebrospinal fluid (CSF) of 26 patients affected by Parkinson’s disease (PD) and 13 age-matched controls to ascertain the potential role of biological fluids as markers for this pathology. Analyses were performed by Inductively Coupled Plasma Atomic Emission Spectrometry and Sector Field Inductively Coupled Plasma Mass Spectrometry. The serum oxidant status (SOS) and anti-oxidant capacity (SAC) were also determined. Results showed a decreasing trend for Al in all the fluids of PD patients, with the strongest evidence in serum. Calcium levels in urine, serum and blood of PD patients were significantly higher than in controls. Copper and Mg concentrations were significantly lower in serum of PD patients. Levels of Fe in urine, blood and CSF of patients and controls were dissimilar, with an increase in the first two matrices and a decrease in CSF. No significant difference was found in levels of Mn between patients and controls. Urinary excretion of Si was significantly higher in PD subjects than in controls. No clear difference between Zn levels in the two groups was found for serum, urine or CSF, but an increase in Zn levels in the blood of PD patients was observed. The SOS level in PD was significantly higher while the corresponding SAC was found to be lower in patients than in controls, in line with the hypothesis that oxidative damage is a key factor in the pathogenesis of PD. The results on the whole indicate the involvement of Fe and Zn (increased concentration in blood) as well as of Cu (decreased serum level) in PD. The augmented levels of Ca and Mg in the fluids and of Si in urine of patients may suggest an involuntary intake of these elements during therapy.

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.

Metal allergens of growing significance: epidemiology, immunotoxicology, strategies for testing and prevention.

Metal-induced allergic contact dermatitis (ACD) is expressed in a wide range of cutaneous reactions following dermal and systemic exposure to products such as cosmetics and tattoos, detergents, jewellery and piercing, leather tanning, articular prostheses and dental implants. Apart from the well known significance of nickel in developing ACD, other metals such as aluminium, beryllium, chromium, cobalt, copper, gold, iridium, mercury, palladium, platinum, rhodium and titanium represented emerging causes of skin hypersensitivity. Despite the European Union directives that limit the total nickel content in jewellery alloys, the water soluble chromium (VI) in cement, and metals banned in cosmetics, the diffusion of metal-induced ACD remained quite high. On this basis, a review on the epidemiology of metal allergens, the types of exposure, the skin penetration, the immune response, and the protein interaction is motivated. Moreover, in vivo and in vitro tests for the identification and potency of skin-sensitizing metals are here reviewed in a risk assessment framework for the protection of consumers health. Avenues for ACD prevention and therapy such as observance of maximum allowable metal levels, optimization of metallurgic characteristics, efficacy of chelating agents and personal protection are also discussed.

A medical-toxicological view of tattooing

Long perceived as a form of exotic self-expression in some social fringe groups, tattoos have left their maverick image behind and become mainstream, particularly for young people. Historically, tattoo-related health and safety regulations have focused on rules of hygiene and prevention of infections. Meanwhile, the increasing popularity of tattooing has led to the development of many new colours, allowing tattoos to be more spectacular than ever before. However, little is known about the toxicological risks of the ingredients used. For risk assessment, safe intradermal application of these pigments needs data for toxicity and biokinetics and increased knowledge about the removal of tattoos. Other concerns are the potential for phototoxicity, substance migration, and the possible metabolic conversion of tattoo ink ingredients into toxic substances. Similar considerations apply to cleavage products that are formed during laser-assisted tattoo removal. In this Review, we summarise the issues of concern, putting them into context, and provide perspectives for the assessment of the acute and chronic health effects associated with tattooing.

Market survey on toxic metals contained in tattoo inks.

Tattooing practice is adopted worldwide and represents an important socio-cultural phenomenon, but, the injection into the skin of coloring agents as metals might pose a risk for allergies and other skin inflammations as well as for systemic diseases. In this context, 56 inks for tattooing purchased from 4 different supply companies were analyzed for metal concentration. Aliquots of pigments were microwave digested by nitric acid, fluoridric acid and hydrogen-peroxide and Al, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Sr and V were quantified by sector field inductively coupled plasma mass spectrometry. Limits of quantification varied from 0.07 ng/ml (Cd) to 10 ng/ml (Al and Fe); recoveries ranged from 92% (Cd and Sb) to 109% (Sr); within- and between-day precisions were 3.2% and 4.67% on average. The relative contribution of metals to the tattoo inks composition was highly variable between brands and colors, even in pigments with the same base color. Elements found as the main components of inks were as follows (in microg/g): Al, 1.59-5893; Ba, 0.058-1226; Cu, 0.076-31,310; Fe, 0.717-88,443; Sr, 0.174-36.4. Toxic metals as Cd, Mn, Pb, Sb and V were over the 1 microg/g in a few cases, while Hg was in traces. Among the allergenic metals, Cr was the highest (0.315-147 microg/g), followed by Ni (0.037-9.59 microg/g) and Co (0.0028-6.43 microg/g) then. On 56 tattoo inks, Cr, Ni and Co exceeded the safe allergological limit of 1 microg/g in 62.5%, 16.1% and 1.8% of cases, respectively.

Baseline Trace Metals in Seagrass, Algae, and Mollusks in a Southern Tyrrhenian Ecosystem (Linosa Island, Sicily)

Trace elements were analyzed in organisms collected at five sampling stations along coastal areas of Linosa Island, Sicily (southern Tyrrhenian Sea, Italy). Concentrations of Cd, Cr, Cu, Pb, and Zn were measured in Posidonia oceanica L. Delile tissues, the two brown algae Padina pavonica (L.) Thivy and Cystoseira sp., and the two gastropod mollusks Monodonta turbinata Born and Patella caerulea L. Seawater samples were also collected at each site to assess soluble metal concentrations and to gain relevant information on their bioaccumulation ability. Data were processed by multivariate techniques, such as principal component analysis (PCA) and linear discriminant analysis on PCA factors. The scoreplots obtained showed that the pollutant distribution is more significantly correlated with species than with sites. For seaweeds, P. oceanica was associated with higher Cd, Cu, and Zn levels; Padina species had higher Cr concentrations, and Cystoseira had higher Pb levels. For mollusks, Monodonta species had high concentrations of Cu and Cr and Patella species were associated with Cd. Some general metal bioaccumulation patterns are described but no one sampling site was more contaminated than the others. The hypothesis of Linosa island serving as a reference ecosystem for baseline trace metal levels in southern Tyrrhenian areas is indeed supported by the statistical comparison among other southern Tyrrhenian ecosystems performed with Kruskall Wallis and Mann-Whitney tests. For P. oceanica leaves, P. pavonica, M. turbinata, and P. caerulea, this study confirms their usefulness as possible cosmopolitan biomonitors of trace metals in marine Mediterranean areas.

Reference values for chromium, nickel and vanadium in urine of youngsters from the urban area of Rome.

In the assessment of human health risk, the obtainment of reference values in biological tissues and/or fluids is crucial to estimate the type and magnitude of occupational and environmental exposure. In this context, urine is the major excretion route for many noxious substances that have entered the organism and can be viewed as one of the most useful materials for biomonitoring campaigns. In this study, reference concentration ranges for Cr, Ni and V in urine were achieved in a sub-population of 131 youngsters, aged 6-10, attending primary schools in the urban area of Rome. Subjects under drug therapy or affected by any pathological diseases were not included in this investigation. Strict precautions against contamination or loss of the analytes of interest were adopted for all steps. Determinations were performed by means of high resolution inductively coupled plasma mass spectrometry. In general, the natural log-transformed concentration data for the three elements investigated conformed to a satisfactorily normal distribution. The estimated reference ranges were as follows (microg g(-1) creatinine): Cr, 0.07-0.76; Ni, 0.20-1.23; V, 0.02-0.22. The sex of the youngsters was tentatively treated as a statistical explanatory variable using the Fischer F-test on variance.