Development of an analytical method for monitoring worker populations exposed to platinum-group elements

Microchemical Journal 76 (2004) 131–140

Development of an analytical method for monitoring worker populations exposed to platinum-group elements Francesco Petruccia,*, Nicola Violantea, Oreste Senofontea, Marco De Gregorioa, Alessandro Alimontia, Sergio Carolia, Giovanni Fortea, Antonio Cristaudob a

` Laboratorio di Tossicologia Applicata, Viale Regina Elena 299, 00161, Rome, Italy Istituto Superiore di Sanita, b Istituto Dermatologico S. Gallicano, Rome, Italy Received 6 October 2003; accepted 9 November 2003

Abstract The increasing industrial use of platinum-group elements (PGEs), namely Ir, Pd, Pt and Rh, and related allergies such as rhinitis, conjunctivitis, asthma, urticaria and contact dermatitis, have led to a growing need to monitor selected populations of exposed workers. In this study, the levels of PGEs were measured in indoor airborne particulate matter and in biological samples taken from employees of a plant where car catalytic converters are produced and precious metals are recovered from spent carbon catalysts. The development of an analytical procedure based on quadrupole inductively coupled plasma mass spectrometry (QICP-MS) for the analysis of PGEs in airborne particulate matter and on sector field inductively coupled plasma mass spectrometry (SF-ICP-MS) for the analysis of PGEs in blood, serum, urine and hair is described. For airborne particulate matter deposited on filters, the limits of detection (LoDs) were found to be 0.006 ng my3, 0.020 ng my3, 0.018 ng my3 and 0.006 ng my3 for Ir, Pd, Pt and Rh, respectively. Repeatability of measurements ranged from 1.8 to 8.5%, while recovery was in the range from 92 to 102%. For biological samples LoDs in blood, serum, urine and hair ranged from (in ng ly1 ) 0.2–0.6 for Ir, 5–10 for Pd, 1–3 for Pt and 2–3 for Rh. For all biological materials, the repeatability varied from 1.1 to 12% for the four elements. Recovery data for the determination of PGEs in biological matrices were found to range from 84.0 to 107.8%. The method was applied to the determination of either total or respirable airborne PGEs collected from five different work areas in the plant. The difference between areas with high and low exposure correlates closely with metal levels in hair, blood and urine. The correlation coefficients between Pt in airborne particulate matter and Pt in biological materials was 0.994, 0.991 and 0.970 for blood, hair and urine, respectively. 䊚 2003 Elsevier B.V. All rights reserved. Keywords: Platinum-group elements (PGE); Airborne particulate matter; Exposed workers

1. Introduction Platinum-group elements (PGEs) such as Ir, Pd, Pt and Rh belong to the transition metals group and their chemical properties are primarily inherent catalytic activity and resistance to corrosion w1x. Background levels of PGEs in the environment are very low: in airborne particulate matter their concentration is below 0.05 pg my3, while that in road dust, sediment, soil and grass is thought to be at level of a few pg gy1 w2–5x. The concentrations of PGEs in the environment have been increasing since the adoption of car catalytic *Corresponding author. Tel.: q39-0649902081; fax: q390649902080. E-mail address: [email protected] (F. Petrucci).

converters as a consequence of their release during vehicle operation w6–9x. In this context, the impact of PGEs in the workplace has raised much concern in metal-finishing industries such as catalyst manufacturing and recycling. There is thus increasing interest in investigating the levels of these metals in occupationally exposed employees. The physiological role of PGEs is not known. Knowledge about possible adverse effects of low levels of exposure is still lacking. Hence, the risk inherent in the exposure to PGEs is still undefined. Some toxicological information about Pt is available, particularly regarding the side effects of its therapeutic use in the treatment of several types of tumors and the high-level occupational exposure to halogenated platinum salts. Diseases caused

0026-265X/04/$ - see front matter 䊚 2003 Elsevier B.V. All rights reserved. doi:10.1016/j.microc.2003.11.005

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by Pt compounds in occupational environments such as refineries and catalyst-manufacturing plants are well documented. After a period of latency varying from a few weeks to several years, more than 50% of exposed workers develop hypersensitivity reactions, i.e. conjunctivitis, rhinitis, bronchial asthma, urticaria or contact dermatitis w10x. Data concerning Ir, Pd and Rh toxicity are still meager. Only a few cases have been reported in the literature of allergic contact dermatitis and contact stomatitis w11–16x. The Italian Ministry of Health financed a project to study the allergic response caused by a new group of substances used in industry. In particular, the study aimed to (i) define the type of allergic reaction caused by PGEs; (ii) study the level of exposure in the workplace w17x; and (iii) determine the levels of metals in biological samples from exposed and unexposed subjects w18–20x. As a part of the above project, the objective of this pilot study was to develop a reliable and sensitive analytical procedure for the measurement of PGEs in the working environment and to biomonitor these metals in blood, plasma, urine and hair of exposed workers. Hair analysis, in particular, is rather advantageous, since this tissue can reflect the total body intake of certain elements better than biological fluids, even though careful evaluation of exogenous contamination is mandatory w21–24x. The determination of PGEs in biological samples requires analytical techniques of adequate detection power. This poses substantial problems to the majority of instrumental analytical techniques, such as electrothermal atomization atomic absorption spectrometry (ETA-AAS), neutron activation analysis (NAA) and inductively coupled plasma emission spectrometry (ICPAES) w25–28x. In this study measurement were performed by sector field (SF) and quadrupole (Q) inductively coupled plasma-mass spectrometry (ICPMS). These are well-established and powerful analytical techniques for the determination of trace and ultra-trace elements in environmental and biological samples. However, this technique is plagued by isobaric interference, this being a major problem in the analysis of PGEs in such matrices. Analytical methods for the determination of PGEs in airborne particulate matter and road dust, as well as in the urine of schoolboys and adults not professionally exposed, were previously reported w29– 32x.

solution department (SSD), salts and solutions of PGEs are used for the production of automotive catalytic converters. This department also prepares solutions of PGEs to be used in other sectors of the plant. To this end, the metals are dissolved in acid and, after precipitation, solubilized in organic and inorganic additives. In the chemical catalyst department (CCD) the acid metal solutions prepared in the SSD are adsorbed on carriers (carbon or alumina substrates), transformed into insoluble compounds and finally washed and dried. The final solid product is a powder or granular catalyst and contains metals at concentrations of 0.5–1%. In the coating department (CD) the acid metal solutions prepared in the SSD are dispersed in a silico-alluminate powder to prepare the substrate by which ceramic or metallic honeycombs or other special supports have to be coated. Once coated, the pieces are finally dried in dryers. In turn, in the recycling department (RD) PGEs are recovered from the carbon spent catalysts by burning them in furnaces or incinerators. Ashes containing PGEs are then thoroughly collected and sent to the refinery department (RFD) where the ashes are leached with acid solutions in order to separate the PGEs. The standard equipment, which is provided with hoods and extraction vents in all sectors, consists of reactors, centrifuges, mixers, dryers, filter-press and vacuum filters. 2.2. Selection of subjects A total of 104 individuals from either the production sectors (number of exposed subjects, 86) or the Administrative Services (AS) (number of internal controls, 18) were included in the study. Moreover, 10 subjects not employed in the plant and living in urban areas have been used as external controls. Each subject filled in a form to provide personal data and job description, general state of health, diet habits, possible use of pharmaceuticals, alcohol, coffee and tobacco, presence of dental implants, etc. All the workers enrolled in the study were tested for skin allergies. Informed consent was obtained beforehand from all subjects. The applicability of the analytical method described hereafter was tested in the case of 25 subjects (15 exposed individuals and 10 controls) out of the 104 subjects thus selected. 2.3. Sample collection and storage

2. Experimental 2.1. Industrial plant and production processes The industrial plant monitored in this study is engaged in the production and recycling of PGEs and is organized in sectors in which the different stages of the productionyrecycling process are carried out. In the salt and

2.3.1. Airborne particulate matter samples Airborne particulate samples were collected by means of personal and area samplers. In the former case, air samples were sucked at a rate of 2.0 l miny1 through cellulose nitrate filters (0.8 mm pore size, 25-mm diameter) by means of GilAir-5 pumps (Sensidyne, Clearwater, FL, USA). Workers wore personal samplers,

F. Petrucci et al. / Microchemical Journal 76 (2004) 131–140 Table 1a Sampling of airborne particulate matter. Indoor sampling Sites

Air volume (m3)

Sampling duration (h)

Sampling type

RFD RFD SSD SSD CD CD CD CD CD CD CD CD CCD CCD CCD CCD RD RD AS AS Outdoor area Outdoor area

87 93 43 77 92 107 110 111 104 101 97 99 109 113 105 117 69 78 123 55 97 108

96 96 36 72 96 120 120 120 120 120 120 120 120 120 120 120 72 72 120 48 96 96

Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work

week week shift shift week week week week week week week week week week week week shift shift week shift week week

Table 1b Sampling of airborne particulate matter. Personal sampling Sites

Air volume (L)

Sampling duration (h dayy1)

Sampling type

RFD RFD SSD SSD CD CD CD CD CD CD CD CCD CCD CCD CCD CCD CCD RD RD RD RD AS

3816 3096 6190 6576 2606 2718 3186 3208 3212 2916 3142 2590 2580 2620 1966 3000 3872 2556 2712 1852 2346 3482

6.4 5.2 10.3 11.0 4.3 4.5 5.3 5.3 5.4 4.9 5.2 4.3 4.3 4.4 3.3 5.0 6.5 4.3 4.5 3.1 3.9 5.8

Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work Work

week week week week week week week week week week week week week week week week week week week week week week

which simulate human breathing and collect the entire range of airborne particulate matter. In order to evaluate exposure to indoor respirable fractions, air samples were collected by means of area samplers equipped with PM10 sampling heads (average particle size -10 mm). In this case, air was pumped at a rate of 17 l miny1 through cellulose ester filters (0.8 mm pore size, 47-mm

133

diameter) by means of a PM-Bravo rotative pump sampler (Tecora, Milan, Italy). The selected sites and sampling periods, including AS and outdoor sites as control areas, are detailed in Tables 1a and 1b. Air sampling was generally performed throughout the work week, but in some cases was carried out during a particular work shift because of the nature of the manufacturing cycle. 2.3.2. Biological samples Four kinds of biological samples were tested, i.e. blood, serum, urine and hair. For blood collection, subjects fasted overnight. The first portion of blood drawn was used to analyze haematological parameters. This also permitted to cleanse the drawing system from inorganic contaminants that could affect the elemental determinations. The subsequent 10 ml of blood were collected in polyethylene tubes (Falcon䉸, Becton Dickinson, Lincoln Park, NJ, USA). From them an aliquot of 1 ml was taken for PGEs measurement in whole blood. The serum matrix was obtained from the residual blood aliquot. Haemolysed serum samples were not discarded. Furthermore, the first urine of the day was collected to which HNO3 was added (Ultrapure, Carlo Erba, Milan, Italy) at a ratio of 1 ml per 100 ml of urine so as to obtain a final acid concentration of 0.14 M. All samples were frozen at y20 8C upon drawing and stored until tested. Hair samples were taken from the occipital area of the head at a distance of approximately 1 cm from the scalp. 2.4. Pretreatment of samples Filters with collected airborne particulate matter were transferred to high-pressure Teflon vessels and added with 3 ml of concentrated HNO3 and 2 ml of H2O2 (Suprapur, Merck, Darmstadt, Germany). The digestion procedure, performed in a Microwave (MW) oven (MLS 1200 MEGA Model, Milestone, Bergamo, Italy), consisted in 5 min steps at powers of 250, 0, 250, 400 and 600 W. After the digestion, an evaporation cycle (15 min at 600 W) was carried out. Finally, the residues were dissolved in 2 ml of HCl (Ultrapure, Carlo Erba, Milan, Italy) to facilitate solubilization of the metals. The final residues were dissolved in high-purity deionized water (Easy Pure UV, International PBI, Milan, Italy) up to a final volume of 50 ml and further diluted 1:10 (vyv) before analysis. Blood and urine samples were digested by means of an ETHOS 900-MEGA 2 MW unit (Milestone, Italy) with a MultiPREP 80 rotor and a temperature control programme. For blood samples, 2 ml of HNO3 were added to the same polyethylene tubes in which they were collected. Digestion was carried out in accordance with the following procedure: (i) overnight predigestion

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Table 2 Instrumental characteristics and settings Q-ICP-MS Instrument Resolution (m Dm y1) RF power Nebulizer Cones Data acquisition

ELAN 5000 (PerkinElmer, Norwalk, CT, USA) 140 at 103Rh 1.0 kW cross flow type Nickel peak hopping; number of sweeps per readings, 3; dwell time, 167 ms; number of replicates, 3; total analysis time, 1 min 14 s plasma, 18.0; auxiliary, 1.0; nebulizer, 1.0 103 Rh, 105Pd, 193Ir, 195Pt 115 In

Argon flows (l miny1) Analytical masses Internal standard mass HR-ICP-MS Instrument Geometry Resolution (m Dmy1) RF power Nebulizer Cones Data acquisition

ELEMENT (Finnigan MAT, Bremen, Germany) double focusing reverse Nier-Johnson 300, 3000, 7500 1.30 kW Meinhard concentric nickel electric scan; 4 runs; 10 passes; number of channels, 1605 scan-time, 8.07 s; total analysis time, 5 min 23 s plasma, 13.0; auxiliary, 0.91; nebulizer, 0.85 103 Rh, 105Pd, 106Pd, 193Ir, 195Pt 115 In

Argon flows (l miny1) Analytical masses Internal standard mass

at 40 8C; (ii) enhancement of temperature up to 80 8C within 1 h; (iii) digestion for 5 h at 80 8C. The digested solution was diluted 1:10 (vyv) with deionized water. For urine, 1 ml was added with 0.5 ml of HNO3, digested for 2 h at 80 8C and finally diluted 1:10 (vyv) with deionized water. Serum samples were simply diluted 1:10 (vyv) with deionized water. Regarding hair, the removal of exogenous contamination is mandatory prior to analysis. This was achieved by means of a careful washing procedure, as already reported w23x. Briefly, samples were repeatedly washed under stirring with a mixture of ethyl ether and acetone (3q1, vyv) (Merck, Germany). After drying, a 5% EDTA solution (Merck, Germany) was added and stirring went on for 1 h. After rinsing with deionized water, the samples were dried in an oven at 85 8C for 16 h, weighed and finally transferred into PTFE containers. The samples were added with 2 ml of HNO3 and digested overnight. One milliliter of H2O2 was then added. The MW digestion settings were as follows: (i) 3 min at 250 W followed by 6 min at 0 W; (ii) 5 min at 250 W and 5 min at 0 W; (iii) 5 min at 450 W; and (iv) 5 min at 500 W. The digestion solutions were diluted up to 20 ml and stored at q2 8C.

MS technique was resorted to. Instrumental details and operating conditions are summarized in Table 2. 2.6. Calibration and interference study The standard addition mode was adopted for calibration by adding diluted single-element standards to the analytical solutions of serum, urine, whole blood, hair and filters. To compensate for instrumental drifts and matrix effects, In was added as the internal standard (IS) to each sample at concentrations of 1 mg ly1 and 10 mg ly1 for biological matrices and filters, respectively. Because of the high content of Cu, Hf, Pb, Rb, Sr, Y and Zn in the airborne matrix, the influence of relevant potential interfering species on the analytical mass signals could not be disregarded. Particular attention was given to the following interferents: 206Pb2q, 40Ar63Cuq, Table 3 Analytical performance of Q-ICP-MS for the quantification of PGEs in digested solution of airborne particulate matter Element

LoDs (mg l

2.5. Instrumentation The determination of PGEs was performed by means of SF-ICP-MS because of the expected very low levels. However, airborne particulate matter had substantially higher concentrations of PGEs and, therefore the Q-ICP-

Ir Pd Pt Rh a

0.02 0.07 0.06 0.02

y1 a

)

(ng m

y3 b

0.006 0.020 0.018 0.006

In analytical solutions. In 24 m3 air filtered volumes. c At concentration of 1 mg ly1. b

)

Repeatabilityc (%)

Recovery (%)

8.5 2.8 2.0 1.8

94 95 96 102

F. Petrucci et al. / Microchemical Journal 76 (2004) 131–140

135

Table 4 LoDs and sensitivity of SF-ICP-MS for the quantification of PGEs in biological matrices Element

Ir Pd Pt Rh

Blood

Serum

Urine

LoDs (ng ly1)

Sensitivity (counts sy1 at 1 ng ly1)

LoDs (ng ly1)

Sensitivity (counts sy1 at 1 ng ly1)

LoDs (ng ly1)

Sensitivity (counts sy1 at 1 ng ly1)

LoDs (ng kgy1)

Sensitivity (counts sy1 at 1 ng ly1)

0.6 10 3 3

282 72 86 373

0.3 7 1 2

487 136 182 607

0.3 10 3 3

271 68 99 305

0.2 5 1 2

444 132 166 620

Table 5 Repeatability of the analysis of 0.5 mg ly1 of PGEs in different matrices Element

Ir Pd Pt Rh

Hair

Intraday precision (%) Blood

Serum

Urine

Hair

3.9 4.6 4.7 2.1

12.0 7.8 7.9 10.0

4.1 3.5 5.1 5.1

1.1 1.6 2.7 1.8

87

Rb16Oq, 87Sr16Oq, 68Zn35Clq and 66Zn37Clq on Rhq; 40Ar65Cuq, 89Y16Oq, 68Zn37Clq and 70 Zn35Clq on 105Pdq; 177Hf16Oq on 193Irq; and 179 Hf16Oq on 195Ptq. On the basis of knowledge accrued so far, the determination of Ir and Pt in biological matrices is not hampered by mass interferences. In fact, 177Hf16Oq and 179 Hf16Oq, the only potential interferents, are in practice negligible because of the very low content of Hf in biological samples. However, measurements of 103Rhq can be affected by 40Ar63Cuq, 87Rb16Oq, 87Sr16Oq, 68 Zn35Clq, 66Zn37Clq and 206Pb2q, those of 105Pdq by 40 Ar65Cuq, 88Sr16OHq, 89Y16Oq, 68Zn37Clq and 70 Zn35Clq and those of 106Pdq by 40Ar66Znq and 103

90

Zr16Oq. The matrices under study contain very high levels of Ca, Cl, K, Mg, Na, P and S, which can also react with Ar, N and O to produce further unknown interfering ion clusters. The analytical mass spectra were investigated at high resolution (m D my1 7500) to study in detail the behavior of these molecular ions. The degree of interference, quantified as apparent concentration, and the relevant correction factor had thus to be experimentally measured. Increasing concentrations of the interfering elements were added to each matrix to match and even exceed their expected ranges of concentration. Standard solutions were prepared daily by diluting 1000 mg ly1 of stock solution of In, Ir, Pd, Pt and Rh (Spex, Edison, NJ, USA) and solutions for the interference studies were set from the single element stock solutions (1000 mg ly1) of Ca, Cu, K, Mg, Na, P, Pb, Rb, S, Sr, Y and Zn (Spex, USA) as well as of Hf (PE pure, PerkinElmer, Norwalk, CT, USA). 2.7. Figures of merit Limits of detection (LoDs) were calculated on the basis of the 3-s criterion. Blanks for airborne particulate matter were obtained from a remote area with very low

Table 6 Recovery data for the determination of PGEs in biological matrices Element

Blood Spike (mg ly1)

Serum Recovery (%)

Urine

Hair

Spike (mg ly1)

Recovery (%)

Spike (mg ly1)

Recovery (%)

Spike (mg ly1)

Recovery (%)

Ir

1 5 10

94.6 95.3 84.0

1 5 10

96.7 98.1 97.8

1 5 10

103.4 102.1 107.8

1 5 10

96.5 94.8 95.1

Pd

1 5 10

102 100.1 97.1

1 5 10

98.3 96.5 95.9

1 5 10

100 96.8 99.0

1 5 10

99.3 98.1 97.4

Pt

1 5 10

96.2 94.5 95.7

1 5 10

97.3 96.5 98.4

1 5 10

104 101 105

1 5 10

94.7 96.3 94.5

Rh

1 5 10

86.5 88.2 86.4

1 5 10

92.3 97.8 98.5

1 5 10

108 103 106

1 5 10

93.1 94.7 94.0

F. Petrucci et al. / Microchemical Journal 76 (2004) 131–140

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Table 7 Concentration of PGEs in respirable airborne particulate matter collected by means of area samplers Sites

Task

Ir (mg my3)

Pd (mg my3)

Pt (mg my3)

Rh (mg my3)

SSD

Preparation of solutions for coating Coating of supports for catalytic converters Adsorption on the carrier Recovery of PGEs from exhausted catalytic converters

0.002

0.06

0.02

0.001

0.6=10y4

0.094

1.71

0.002

0.7=10y4 0.9=10y4

2.1 10.6

0.23 0.18

0.003 0.001

0.5=10y4 -LoD (6=10y6)

0.006 -LoD (2=10y5)

0.008 -LoD (1.8=10y5)

0.001 -LoD (6=10y6)

CD CCD RD

AS Controls

PGEs concentration and for biological samples from non-exposed subjects. The same samples, spiked as needed, were used for the within-series imprecision tests. Because of the lack of reference materials with certified levels of PGEs for the matrices under study, recovery data were used instead of accuracy results. To this end, a solution containing Ir, Pd, Pt and Rh was adsorbed on a filter prior to MW digestion so as to obtain a final spiked concentration of 1 mg ly1. For biological samples, each matrix was spiked with aliquots of 1, 5 and 10 mg ly1 of the analytes prior to treatment. 3. Results 3.1. Interference study 3.1.1. Airborne particulate samples Of the interfering species affecting the 103Rhq signal, the influence of 87Rb16Oq and 87Sr16Oq was negligible, probably because of the poor oxide formation in this matrix. The contributions of 40Ar63Cuq, 68Zn35Clq, 66 Zn37Clq and 206Pb 2q could also be disregarded when compared with the high content of Rh in airborne particulate matter samples. The Pd determination was achieved at mass 105, where the most relevant potential interferences come from the polyatomic ions 40 Ar65Cuq, 89Y16Oq, 68Zn37Clq and 70Zn35Clq. The formation of 89Y16Oq was the only species to be considered for mathematical correction, while the contribution of molecular ions forming from Cu and Zn was scarce and required no corrections. Platinum and Ir were determined at mass 195 and 193, respectively. Both might be impaired by the formation of the 179Hf16Oq and 177Hf16Oq molecular ions. Results showed that the experimental contribution of Hf was in practice negligible. On the basis of the above considerations Ir, Pt and Rh were determined with Q-ICP-MS without any correction for potentially interfering elements, whereas the following mathematical equation was used for 105Pdq:

I

105

PdqsI 105ywI

89

Yq=CFx

where I is the Intensity (counts sy1) and CF is the daily Correction Factor obtained by ratioing the intensities of 89 16 q Y O and 89Yq as measured in the solutions spiked with increasing amounts of Y. 3.1.2. Biological material The selection of the analytical ions 193Irq, 105Pdq, 106 Pdq, 195Ptq and 103Rhq out of those available was dictated by their high abundance as well as by the fact that they are subject to scarce interference. For the matrices under study, the mass spectra obtained at high resolution (m D my1 7500) showed single peaks in all the analytical masses with the exception of 105Pdq, which presented two distinct peaks. However, the influence of this unknown interference on the 105Pd signal was negligible, i.e. no more than 5% of the total intensity. Other potential sources of interference, which could not be separated even at high resolution, were evaluated in the low-resolution (m D my1 300) mode. In particular, the low concentrations of Hf, Y and Zr in these samples implies that the effects of the relevant oxides on 193Irq, 195Ptq, 105Pdq and 106Pdq are negligible. The contribution of various ZnCl molecular ions on 105Pdq and 103Rhq also appeared not to be substantial, in spite of the high content of both elements in these matrices. Similarly, the potential ions deriving from elements at very high concentrations, such as Ca, K, Mg, Na, P and S, were studied in both the low- and high-resolution modes at the masses 103 and 105. No significant increase in intensity was observed even after adding up to 25 mg ly1 of Ca and Mg, 10 mg ly1 of K, P and S and 500 mg ly1 of Na. Oxides, such as 87Rb16Oq and 87Sr16Oq, and argide ions, such as 40Ar63Cuq and 40Ar65Cuq, did not affect the determination of 103Rhq or 105Pdq because their contributions were much less than the signals of Rh and Pd in the samples. It would be possible in any case to use mathematical equations to correct such interferences.

Department Ir

Pd

Pt

Rh

Blood Serum Urine Hair Blood Serum Urine Hair Blood Serum Urine Hair Blood Serum Urine Hair (mg ly1) (mg ly1) (mg ly1) (mg gy1) (mg ly1) (mg ly1) (mg ly1) (mg gy1) (mg ly1) (mg ly1) (mg ly1) (mg gy1) (mg ly1) (mg ly1) (mg ly1) (mg gy1) SSD CD CCD RD AS Controls

0.02 2.05 0.03 0.15 0.04 0.001

0.02 0.74 0.03 0.16 0.02 0.001

0.015 0.01 0.01 0.01 0.01 0.001

0.0044 0.204 0.0005 0.0042 0.0005 0.0002

0.74 2.23 0.72 0.54 0.01 -LoD

0.41 0.71 0.65 0.41 0.01 -LoD

0.285 0.295 2.1 0.95 0.205 -LoD

0.78 1.82 3.25 5.18 0.09 -LoD

0.11 2.90 0.11 0.21 0.05 0.006

0.08 1.55 0.04 0.15 0.03 0.002

0.405 2.065 0.145 0.13 0.155 0.003

0.24 2.55 0.15 0.22 0.04 0.001

0.11 2.94 0.21 0.15 0.14 -LoD

0.13 1.36 0.17 0.11 0.10 -LoD

0.12 0.27 0.09 0.09 0.10 0.005

0.11 0.31 0.02 0.02 0.03 -LoD

F. Petrucci et al. / Microchemical Journal 76 (2004) 131–140

Table 8 Preliminary biomonitoring data (means of three subjects from each working area and of 10 subjects from control area)

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F. Petrucci et al. / Microchemical Journal 76 (2004) 131–140

138

Fig. 2. Concentrations of Pt in biological and environmental matrices in different areas of the plant. SSD: salt and solution department; CD: coating department; CCD: chemical catalyst department; RD: recycling department; AS: administrative services.

Fig. 1. Respirable airborne particulate matter Pt (a) and Pd (b) distribution in different areas of the plant. SSD: salt and solution department; CD: coating department; CCD: chemical catalyst department; RD: recycling department; AS: administrative services.

Surprisingly, increasing additions of Sr gave rise in all matrices to a signal at mass 105, much higher than that expected, on the basis of the abundance of 88Sr17Oq. The signal increase at mass 105, probably due to the formation of 88Sr16OHq, was particularly serious in urine because of the higher content of Sr. For this reason, 106Pdq corrected for the isobaric interference of 106 Cdq, was preferred to 105Pdq. Finally, with reference to the interference of 206Pb2q on 103Rhq, the following corrective equation was resorted to: I

103

RhqsI 103ywI 103.5=IRx

where I is the Intensity (counts sy1) and IR is the isotopic abundance ratio between the masses 206Pb and 207 Pb w29x. 3.2. Analytical performances For airborne particulate matter samples, Table 3 reports the LoDs, precision and recovery. In consideration of the high content of PGEs in this matrix, the

detection power achieved by Q-ICP-MS turned out to be adequate. Repeatability of measurements at 1.0 mg ly1 was, with the only exception of Ir, lower than 3%, this providing evidence of the reliability of the entire analytical procedure. Although recovery data cannot replace accuracy tests, the range of 94 and 102% provide some evidence of good control over contamination during the digestion procedure, negligible absorption on the vessel walls and complete dissolution of PGEs during treatment. Tables 4–6 set forth the LoDs, sensitivity, repeatability and recovery for the determination of PGEs in biological matrices. According to the data of Table 4, the detection power achieved by SF-ICP-MS equipped with pneumatic nebulizer was adequate to analyze the expected concentrations of PGEs in the matrices studied. Measurements of 89Y16Oq in diluted serum (1:10 with water vyv) and diluted digested hair (1:25 with water vyv) were characterized by a higher sensitivity than those of digested blood and urine because of their lower acid content (0–2% vs. 5–10% of added HNO3, respectively). The reliability of the overall treatment and instrumental procedures is proven by the satisfactory repeatability obtained on ten measurements, as shown in Table 5. At a concentration of 0.5 mg ly1, precision varied from 1.1 to 5.1 for the digested solutions (blood, hair and urine) and from 7.8 to 12 for water-diluted serum. In the latter case, the presence of organic matter may account for some instability in the analytical signal, which cannot be fully counterbalanced for by the use of the internal standard. The results of the recoveries reported in Table 6 were in good agreement with the added amounts for all elements, with the exception of

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Rh in digested blood, for which a recovery lower than 90% was achieved. 3.3. Preliminary application The analytical approach thus developed was tested in a number of cases as described below. The concentrations of PGEs in indoor airborne particulate matter collected from four different areas of the plant as a function of the type of activity and in the AS assumed to be non-exposed areas are given in Table 7. The control values reported here are referred to the levels of PGEs in indoor environments far away from the plant. In all sites, the presence of Rh and Ir was very low, since these two elements are very rarely used in production processes. Emissions of Pd and Pt to indoor environments, however, depended on which work shift was being carried out at the time of collection. More specifically, the emission of PGEs was very low in the SSD, always below the threshold limit value (TLV) for airborne soluble PGEs, i.e. 2 mg my3. In this area, all processes are completed in a closed reactor and the dissolved PGEs are transferred to other departments by means of pipes. The highest concentration of Pt in airborne particulates was found, as expected, in the CD, where the supports are coated by PGEs, primarily by using chloroplatinic acid in the case of Pt. Although all the equipment is effectively provided with hoods and extraction vents and the oven plant is self-contained, aerosols and dust powder are nonetheless able to spread in the indoor environment. In the CCD, where the acid metal solutions are adsorbed on the carrier, the Pd concentration in respirable airborne particulate matter was higher than that of Pt, probably because of the particular production process carried out during the sampling period. In the RD the spent carbon catalysts are burned in furnaces and then ground and sieved. Surfaces in this area were found to be covered with a fine dust originating from the grading and preparation steps. Palladium was at a very high concentration, five times over the soluble PGEs-TLV. Finally, the administrative area showed very low levels of PGEs, albeit at least two orders of magnitude higher than those of the remote control sites. Fig. 1(a,b) summarizes the Pd and Pt emissions in the various departments of the plant. Table 8 compares the results obtained for PGEs concentrations of three individuals from each different sector of the plant with those for an external control urban population. On the whole, the workers employed in the CD had the highest body load for all four elements, the only exception being Pd in urine and hair. The highest levels of Pd in urine and hair were found in personnel working in the CCD and RD. The latter findings, along with the Pt biological data, were in good agreement with data obtained by area samplers. Fig. 2 shows the correlation between environmental emission

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and Pt body load in different areas of the plant. The differences between areas with high and low exposure correlate well with the levels of the metal in hair, blood and urine. The correlation coefficients (r) between Pt levels in air and in biological matrices were 0.994, 0.991 and 0.970 for blood, hair and urine, respectively. 4. Conclusions Although some of the analytical problems associated with the determination of PGEs in biological fluids of non-exposed individuals have not yet been completely solved, the data reported here clearly indicate that ICPMS techniques are fully adequate for monitoring occupationally exposed populations. The present findings for both biological and air samples were well above the LoDs of the techniques and satisfactory control on potential mass interferences could be achieved. The overall performance of the method in terms of recovery, precision and sensitivity allowed PGEs levels to be reliably measured. The findings of this pilot study are probative of the fact that exposure to PGEs in the industrial plant varies according to the different production processes and working areas. Other studies already in progress aim at elucidating the relationship, if any, between the body load of these elements and the related allergic reactions in order to shed further light on this important issue of occupational health. In conclusion, the analytical procedures described are fit for monitoring of outdoor and indoor exposure to PGEs and also enable differences to be detected among the levels of exposure of groups of workers as a function of specific activities. References w1x S.A. Cotton (Ed.), Chemistry of Precious Metals, Chapman and Hall, London, UK, 1997. w2x H. Renner, G. Schmuckler, in: E. Merian (Ed.), Metals and their Compounds in the Environment, Wiley-VCH, Weinheim, Germany, 1991, pp. 1131–1151. w3x D.E. Johnson, J.B. Tillery, R.J. Prevost, Environ. Health Persp. 12 (1975) 27–32. w4x F. Alt, H.R. Eschnauer, B. Megler, J. Messerschmidt, G. Tolg, ¨ Fresenius J. Anal. Chem. 357 (1997) 1013–1018. w5x E. Helmers, N. Merghel, Fresenius J. Anal. Chem. 362 (1998) 522–528. w6x S. Rauch, G.M. Morrison, M. Motelica-Heino, O.F.X. Donard, in: Proceedings of the Eighth International Conference on Urban Storm Drainage, Sydney, Australia. The Institution of Engineers, Sydney, Australia, 1999, vol. 1, pp. 202–209. w7x C. Wei, G.M. Morrison, Sci. Tot. Environ. 146–147 (1994) 169–176. w8x C.B. Tuit, G.E. Ravizza, M.H. Bothner, Environ. Sci. Technol. 34 (2000) 927. w9x S. Caroli, A. Alimonti, F. Petrucci, B. Bocca, F. Forastiere, Spectrochim. Acta B 56 (2001) 1241–1248. w10x G.M. Levence, Br. J. Dermatol. 85 (1971) 590–593.

140

F. Petrucci et al. / Microchemical Journal 76 (2004) 131–140

w11x C. Cavelier, J. Foussereau, Kontaktallergie gegen Metalle und deren Salze. Teil II: Nickel, Cobalt, Quecksilber und Palladium, Dermatosen 43 (1989) 202–209. w12x A. Henne, G.A. Wiesmuller, ¨ G. Leng, IV-2.1.18 Palladium, in: J. Konietzko, H. Dupuis (Eds.), Handbuch der Arbeitsmedizin, Ecomed Verlagsgesellschaft, LandsbergyLech, 1989, pp. 1–20. w13x G.A. Wiesmuller, ¨ A. Henne, G. Leng, VI-3 MetalleyPalladium, ¨ ¨ in: H.E. Wichmann, H.W. Schlipkoter, G. Fulgraff (Eds.), Handbuch der Umweltmedizin, Ecomed Verlagsgesellschaft, LandsbergyLech, 1992, pp. 1–16. w14x A. Bergman, U. Svedberg, E. Nilsson, Contact Dermatitis 32 (1995) 14–17. w15x J.J. Hostyneck, R.S. Hins, C.R. Lawrence, M. Price, R.H. Guy, CRC Crit. Rev. Toxicol. 93 (1993) 171–235. w16x J. De La Cuadra, M. Grau-Massanes, Contact Dermatitis 25 (1991) 182–184. w17x A.D. Maynard, C. Northage, M. Hemingway, S.D. Bradley, Ann. Occup. Hyg. 41 (1997) 77–94. w18x R. Shierl, H. G. Fries, C. Van de Weyer, G. Fruhmann, Occup. Environ. Med. 55 (1998) 138–140. w19x J. Begerow, U. Sensen, G.A. Wiesmuller, ¨ L. Dunemann, Zbl. Hyg. Umweltmed. 202 (1999) 411–424. w20x R. Merget, R. Kulzer, A. Kniffka, F. Alt, R. Breitstadt, T. Bruening, Int. J. Hyg. Environ. Health 205 (2002) 347–351.

w21x T. Takayuchi, Y. Nakano, A. Aoki, Ann. Rep. Res. Reactor Inst. Kyoto Univ. 19 (1986) 89–98. w22x J. Chlopicka, P. Zagrodzki, Z. Zachwieja, M. Krosniak, M. Folta, Analyst 120 (1995) 943–945. w23x O. Senofonte, N. Violante, S. Caroli, J. Trace Elem. Med. Biol. 14 (2000) 6–13. w24x N. Violante, O. Senofonte, G. Marsili, P. Meli, M.E. Soggiu, S. Caroli, Microchem. J. 67 (2000) 397–405. w25x P. Shearen, M.R. Smyth, Analyst 113 (1988) 609. w26x J. Kucera, J. Drobnik, J. Radioanal. Chem. 75 (1982) 71. w27x S. Caroli, A. Alimonti, P. Delle Femmine, F. Petrucci, O. Senofonte, N. Violante, et al., J. Atom. Anal. Spectrom. 7 (1992) 859–864. w28x F. Morazzoni, C Canevali, I. Moschetti, R. Todeschini, S. Caroli, A. Alimonti, et al., Cancer Chemother. Pharmacol. 35 (1995) 529–532. w29x M. Krachler, A. Alimonti, F. Petrucci, K.J. Irgolic, F. Forestiere, S. Caroli, Anal. Chim. Acta 363 (1998) 1–10. w30x F. Petrucci, B. Bocca, A. Alimonti, S. Caroli, J. Anal. At. Spectrom. 15 (2000) 525–528. w31x F. Petrucci, B. Bocca, A. Alimonti, ICP Newsletter 27 (2002) 246–251. w32x B. Bocca, A. Alimonti, A. Cristaudo, E. Cristallini, F. Petrucci, S. Caroli, Anal. Chim. Acta (2004) in press.