Edoardo Menichini

The temporal variability of the profile of carcinogenic polycyclic aromatic hydrocarbons in urban air: a study in a medium traffic area in Rome, 1993–1998

Abstract The constancy, both temporal and spatial, of the profile of polycyclic aromatic hydrocarbons (PAHs) relative to benzo[a]pyrene (BaP) is a prerequisite to using the BaP-indicator approach in the carcinogenic risk assessment for PAHs. The principal aim of this study was to provide a contribution to validate this approach, by studying the variability of the profile at a typical urban site through a multi-year data set and by comparing the profiles available for different cities. Seven carcinogenic PAHs (benz[a]anthracene, benzo[b+j+k]fluoranthenes, BaP, indeno[1,2,3-cd]pyrene, dibenz[a,h]anthracene) were determined in PM10 24-h samples collected every third day at a road site; moreover, benzo[e]pyrene was determined as a reference PAH due to its stability. The profile was found stable from year to year. Besides, it was similar to those recently found in other European cities (observed differences within a factor of four) and to those elaborated from earlier (1970s–1980s) investigations. The substantial similarity of profiles, both temporal (on an annual basis) and spatial, supports the validity of the BaP-indicator approach. Large PAH-to-PAH differences were, however, found in the seasonal pattern of profile: they were explained by the different atmospheric degradability of PAHs, whose effect is enhanced under the meteoclimatic conditions typical of the European Mediterranean countries. PAH annual means showed a slight declining trend since 1994. In the last sampling year, mean concentration of BaP was 1.2 ng m−3. Within-year differences among monthly averaged PAH concentrations were observed, as large as up to 44-fold for BaP, underlining the need for whole-year monitoring.

Urban air pollution by polycyclic aromatic hydrocarbons: levels and sources of variability

The atmospheric levels of polycyclic aromatic hydrocarbons (PAHs), measured since the mid-1970s from approximately 60 towns world-wide, are reviewed. For each investigation, a concise description of sampling conditions and analytical methods is also given. The strongly carcinogenic benzo[a]pyrene was typically found in the range of 1-20 ng/m3 in Europe, and around 1 ng/m3 in the USA. For other PAHs, individual concentrations were generally in the range of 1-50 ng/m3 in Europe, 0.1-1 in North and South America and in Australia, 1-10 in Japan, and 10-100 in two towns in India and New Zealand. Data on the size distribution of PAH-containing particles are also presented, showing that PAH content is adsorbed mostly on respirable particles. The ratios of winter to summer levels, and of urban to rural levels, were found in the range of 2-10 in both cases. PAH levels have progressively decreased in the last few decades, most probably due to the introduction of anti-smoke regulations and the decrease of coal burning for heating. Measurements from different investigations can only be compared with great prudence, owing to sampling factors which can affect results. Sources of urban PAH contamination and of the variability in levels are discussed.

Polycyclic aromatic hydrocarbons in olive oils on the Italian market

The six olive oils and seven virgin olive oils which are most consumed in Italy were analysed for 28 polycyclic aromatic hydrocarbons (PAHs). The aim was to evaluate whether a carcinogenic hazard for the general population can derive from the dietary intake of this food, which is consumed particularly highly in the Mediterranean area. The analytical method involved extraction by liquid-liquid partition, filtration on silica gel, clean-up by thin-layer chromatography on silica gel, and analysis by high-resolution gas chromatography with a flame ionization detector. The 3- and 4-ring PAHs which are most abundant in the environment were found in all samples, at individual levels up to ca. 40 micrograms/kg (for phenanthrene); no important difference was observed between olive oils and virgin olive oils. PAHs which are most suspected of being carcinogenic for humans were not detected (limit of detection, ca. 3 micrograms/kg). The average yearly intake of the detected PAHs through this food was estimated at ca. 0.56 mg per capita.

Artificial-turf playing fields: contents of metals, PAHs, PCBs, PCDDs and PCDFs, inhalation exposure to PAHs and related preliminary risk assessment.

The artificial-turf granulates made from recycled rubber waste are of health concern due the possible exposure of users to dangerous substances present in the rubber, and especially to PAHs. In this work, we determined the contents of PAHs, metals, non-dioxin-like PCBs (NDL-PCBs), PCDDs and PCDFs in granulates, and PAH concentrations in air during the use of the field. The purposes were to identify some potential chemical risks and to roughly assess the risk associated with inhalation exposure to PAHs. Rubber granulates were collected from 13 Italian fields and analysed for 25 metals and nine PAHs. One further granulate was analysed for NDL-PCBs, PCDDs, PCDFs and 13 PAHs. Air samples were collected on filter at two fields, using respectively a high volume static sampler close to the athletes and personal samplers worn by the athletes, and at background locations outside the fields. In the absence of specific quality standards, we evaluated the measured contents with respect to the Italian standards for soils to be reclaimed as green areas. Zn concentrations (1 to 19 g/kg) and BaP concentrations (0.02 to 11 mg/kg) in granulates largely exceeded the pertinent standards, up to two orders of magnitude. No association between the origin of the recycled rubber and the contents of PAHs and metals was observed. The sums of NDL-PCBs and WHO-TE PCDDs+PCDFs were, respectively, 0.18 and 0.67×10(-5) mg/kg. The increased BaP concentrations in air, due to the use of the field, varied approximately from <0.01 to 0.4 ng/m(3), the latter referring to worst-case conditions as to the release of particle-bound PAHs. Based on the 0.4 ng/m(3) concentration, an excess lifetime cancer risk of 1×10(-6) was calculated for an intense 30-year activity.

On-filter degradation of particle-bound benzo[a]pyrene by ozone during air sampling: a review of the experimental evidence of an artefact.

On-filter loss of benzo[a]pyrene (BaP) during air sampling due to reaction with ozone was observed in several experimental studies. It was also of concern in the recent CEN method for BaP measurement in ambient air: a denuder-based sampling system minimising this loss is described in the method but, due to the scarcity of validated data, is not yet ready to be used for normative purposes. This paper presents a review of the available experimental results on this artefact, as reported in 16 published studies, with the aim of assessing the state of knowledge regarding its occurrence and extent. Almost all field studies showed that, regardless the type of sampling site, the on-filter BaP degradation by O(3) constituted a not negligible artefact. When limiting the analysis of the results to the field sampling campaigns carried out under real-world conditions, mean BaP losses were typically in the 20-55% range (hence causing underestimates of mean BaP concentrations possibly in the order of 100%), with daily maxima up to 71%. The duration of the campaigns was typically of a few days; no experimental results are available on the actual O(3) effect on the BaP annual mean. Various factors were investigated as potential contributors to the O(3) effect, although their role has yet to be clarified: O(3) concentration, relative humidity, distance from BaP sources, size distribution and source of particles, sampling duration. The use of denuders for O(3) removal in the sampling system substantially eliminates this artefact, but their application and performance must still be validated.

Reliability assessment of a gas chromatographic method for polycyclic aromatic hydrocarbons in olive oil

A quality control test was developed for a gas chromatographic method to determine polycyclic aromatic hydrocarbons in olive oil. Fifteen oil specimens were fortified with eight three- to six-ring polycyclic aromatic hydrocarbons at levels of between 3.0 (approximate detection limit) and 360 micrograms/kg. Three sets of five equally fortified specimens were obtained and assayed at random by three operators. For each fortification level, the means of recovery yield were in the range 56-107%, and were independent of the polycyclic aromatic hydrocarbon congener specificity and the operators capability. Excluding subsets of data associated with both the fortification level at the detection limit and a deviant polycyclic aromatic hydrocarbon term (benzo[ghi]perylene), an overall mean accuracy of 96% and a precision of 7% were achieved.

A 3-year study of relationships among atmospheric concentrations of polycyclic aromatic hydrocarbons, carbon monoxide and nitrogen oxides at an urban site

Abstract Particle-bound carcinogenic PAHs (benzo[a]pyrene, benzofluoranthene isomers, indeno[1,2,3-cd]pyrene), benzo[e]pyrene (selected as a stable reference PAH), CO and nitrogen oxides (NO, NO2 and NOx) were simultaneously measured at a street site in Rome. The aim was to investigate the possibility of using a conventional air quality parameter as a surrogate for carcinogenic PAHs at urban sites. Eighty-seven sample sets, corresponding to 344 sampling days, were statistically treated by standard univariate and bivariate methods. NO and NOx were the parameters most strongly correlated with PAHs (overall mean r=0.92, for both), with the highest linearity and lowest scattering of data in the regression lines, but CO also showed a very good correlation (r=0.86). Temporal variations of all these substances were substantially superimposable throughout the study. Summer results indicate, however, that PAH degradation may affect correlation under conditions of relatively high temperature and sunlight intensity. This preliminary investigation suggests that, at street level where pollution is traffic dominated, NO could be the most valid surrogate to roughly estimate PAH concentrations and trends, or PAH pollution ranking within a monitoring network.

Dibenzopyrenes, other PAHs with molecular weight 302, and selected carcinogenic PAHs seldom determined: identification and one-year quantification in urban air

The unambiguous identification in environmental samples of the potent carcinogen dibenzo[a,l]pyrene (DBalP) and the other DBPs (DBaeP, DBaiP, DBahP), whose evidence of carcinogenicity was recently re-evaluated by the International Agency for Research on Cancer (IARC), is an analytical challenge. This is attributed to their low concentrations in the environment and to the co-presence of several 302 MW isomers. In this study the four DBPs were identified in air, together with further four isomers with MW 302, based on an overall evaluation of five acceptance criteria. Their annual mean concentrations were quantified, for the first time to our knowledge. Thirteen other isomers were tentatively identified by comparison with previously published gas chromatographic profiles. The determinations were performed on PM10 samples collected every sixth day at a site in Rome, solvent extracted and analysed using GC/LRMS. The primary objective was to determine the mean DBP concentrations the population may be exposed to, and their consequent carcinogenic risks relative to benzo[a]pyrene (BaP) taken as a reference polycyclic aromatic hydrocarbon (PAH). The mean concentrations of DBalP, DBaeP, DBaiP and DBahP were, respectively, 0.014, 0.07, 0.02 and 0.01 ng m−3 (BaP: 0.65 ng m−3). Based on the available toxicity equivalence factors, DBalP contributed the carcinogenic risk of the PAH mixture by a factor of 2 relative to the risk attributable to BaP. DBaeP, DBahP and DBaiP contributed by, respectively, 11%, 1% and 0.3% of BaP. The instrumental conditions used to determine the 302 MW isomers allowed to unambiguously identify and to quantify other PAHs, ‘possibly carcinogenic’ to humans according to IARC, whose atmospheric concentrations reported in literature are scarce or missing: benzo[c]phenanthrene, 5-methylchrysene and benzo[j]fluoranthene (the latter being baseline resolved from isomers b and k). Finally, for completeness of information on PAHs recently upgraded by IARC to ‘possibly carcinogenic’, the concentrations of cyclopenta[cd]pyrene are reported.

Monitoring of carcinogenic PAHs in air under mild–warm ambient temperatures: relative importance of vapour- and particulate-phase analyses in assessing exposure and risk

Atmospheric polycyclic aromatic hydrocarbons (PAHs) are often determined by collecting only the particulate phase. The aim of this study was to ascertain in the field to what extent not collecting the vapour phase may affect the exposure assessment and the risk assessment for carcinogenic PAHs, under ambient temperatures typical of Southern Europe. PM10 24-h samples were collected in Rome every two months throughout one year on a filter backed by two polyurethane foam sections. Daily mean temperatures during sampling reached 31°C, with hourly maximum values up to 36°C. While four-ring PAHs were found in the vapour phase to a large extent, the calculated annual means of five-ring PAHs, including benzo[a]pyrene, were not affected significantly by the amounts collected as vapour phase. By using the “toxicity equivalence factor” approach, the carcinogenic risk overall attributable to particle-bound PAHs accounted for at least 97% of the risk attributable to total (particulate + vapour phase) PAHs.

TREND OF ATMOSPHERIC BENZO[ a ]PYRENE IN ITALY BEFORE THE ADOPTION OF THE EUROPEAN DIRECTIVE ON PAHs

The benzo[a]pyrene temporal trend was investigated in 11 towns where at least five annual means were available. The overall number of stations was 22, of which 12 were traffic-oriented, 6 background and 4 industrial. The trend was generally declining at traffic-oriented sites and roughly stable at background sites. The annual means in 2004 still exceeded the forthcoming European target value of 1 ng/m 3 in two towns (up to 1.9 ng/m 3 ). The background means (up to 1.4 ng/m 3 in 2004) accounted for approximately 40–90% of those at the traffic-oriented sites in the same town. The presence of a coke plant was incompatible with the attainment of the target value, while the adoption of technical measures on a carbon electrode plant was successful in attaining concentrations lower than the target value. In heavy traffic areas in Italy, the attainment of the target value hardly appears feasible under the current conditions of traffic congestion.