Skin disease after occupational dermal exposure to coal tar: a review of the scientific literature

Acne vulgaris: advances in pathogenesis and prevention strategies

PURPOSE

The aim is to encourage the creation of innovative prevention and treatment measures and to help readers in selecting the most effective ones.

BACKGROUND

Acne vulgaris is the most prevalent skin condition of adolescents, affecting approximately 9% of the global population. Patients become more prone to mental and psychological problems because of it. Several strategies have been established to effectively improve acne vulgaris. However, the complexity of its pathogenesis and the limitations of the existing strategies to control it in terms of bacterial resistance, patient compliance, and safety have made the development of new control strategies a hot topic in skin health research.

RESULTS

This review systematically summarizes the pathogenesis and prevention strategies of acne vulgaris according to the most recent studies. The limitations of the current research on acne vulgaris and future research directions are presented based on the analysis of the strengths and weaknesses of the existing prevention and treatment strategies.

Pathophysiology and Treatment of Psoriasis: From Clinical Practice to Basic Research

Psoriasis, a chronic inflammatory dermatosis, represents a significant clinical challenge due to its complex pathogenesis and the limitations of existing therapeutic strategies. Current psoriasis diagnoses are primarily clinician-dependent, with instrumental diagnostics serving as adjuncts. Ongoing research is progressively deciphering its molecular underpinnings; the future of psoriasis diagnostics may involve genetic and immunological profiling to pinpoint biomarkers, enabling more accurate and timely interventions. The administration of psoriasis medications, whether oral, injectable, or topical, is associated with a range of side effects and compliance issues. Topical medications, despite their advantages in patient compliance and reduced systemic side effects, are hindered by the altered skin barrier in psoriasis, which impedes effective drug penetration and retention. In recent years, the development of novel transdermal drug delivery systems represents a promising frontier in psoriasis management. Nanotechnology-, microneedle- and dressing-based systems have demonstrated the potential for improved skin penetration, enhanced bioavailability, or extended retention time. Here, we will focus on the latest insights into the etiology, diagnostic methodologies, and therapeutic approaches for psoriasis, with a particular emphasis on the evolution and challenges of novel transdermal drug delivery systems.

Artemisia monosperma essential oil nanoformulations alleviate imiquimod-induced psoriasis-like dermatitis in mice

Psoriasis is an inflammatory immune-mediated skin disease that affects nearly 2-3 % of the global population. The current study aimed to develop safe and efficient anti-psoriatic nanoformulations from Artemisia monosperma essential oil (EO). EO was extracted using hydrodistillation (HD), microwave-assisted hydrodistillation (MAHD), and head-space solid-phase microextraction (HS-SPME), as well as GC/ MS was used for its analysis. EO nanoemulsion (NE) was prepared using the phase inversion method, while the biodegradable polymeric film (BF) was prepared using the solvent casting technique. A.monosperma EO contains a high percentage of non-oxygenated compounds, being 90.45 (HD), 82.62 (MADH), and 95.17 (HS-SPME). Acenaphthene represents the major aromatic hydrocarbon in HD (39.14 %) and MADH (48.60 %), while sabinene as monoterpene hydrocarbon (44.2 %) is the primary compound in the case of HS-SPME. The anti-psoriatic Effect of NE and BF on the successful delivery of A.monosperma EO was studied using the imiquimod (IMQ)-induced psoriatic model in mice. Five groups (n = 6 mice) were classified into control group, IMQ group, IMQ+standard group, IMQ+NE group, and IMQ+BF group. NE and BF significantly alleviated the psoriatic skin lesions and decreased the psoriasis area severity index, Baker's score, and spleen index. Also, they reduced the expression of Ki67 and attenuated the levels of tumor necrosis factor-alpha, interleukin 6, and interleukin 17. Additionally, NE and NF were able to downregulate the NF-κB and GSK-3β signaling pathways. Despite the healing properties of BF, NE showed a more prominent effect on treating the psoriatic model, which could be referred to as its high skin penetration ability and absorption. These results potentially contribute to documenting experimental and theoretical evidence for the clinical uses of A.monosperma EO nanoformulations for treating psoriasis.

Updated view of tars for psoriasis: what have we learned over the last decade?

Tars are one of the most effective, unknown, and oldest therapies for psoriasis. They include coal tar (CT) and biomass-derived products. These treatments, particularly the CT, have proven to be cost-effective with long remission times compared to other systemic or topical treatments. However, they have hardly evolved in recent years, as they are not well-embraced by clinicians or patients because of concerns regarding cosmesis and safety. This review summarizes current knowledge about the chemical characterization, mechanism of action, toxicity, and clinical studies supporting the use of tars for psoriasis over the last decade. Trends within these above aspects are reviewed, and avenues of research are identified. CT is rich in polycyclic aromatic hydrocarbons, whereas biomass-derived tars are rich in phenols. While the activation of the aryl hydrocarbon receptor is involved in the antipsoriatic effect of CT, the mechanism of action of biomass-derived products remains to be elucidated. No conclusive evidence exists about the risk of cancer in psoriasis patients under CT treatment. Large, randomized, double-blind, controlled clinical trials are necessary to promote the inclusion of tars as part of modern therapies for psoriasis.

Urinary levels of monohydroxylated polycyclic aromatic hydrocarbons in Brazilian children and health risk assessment: a human biomonitoring-based study

Monitoring human exposure to polycyclic aromatic hydrocarbons (PAHs) is a public health concern. Children are a vulnerable subgroup of the population with limited human biomonitoring data worldwide. Thus, this study aimed to measure the levels of seven PAH metabolites in urine from Brazilian children and provide risk assessment values for this exposure. Our data show naphthalene was the major contributor to children's exposure to PAHs, with a 100% detection rate. Children in urban regions presented higher exposure to PAHs, with higher concentrations of 2-naphthol in the southeast (1.09 ng/mL, p < 0.05). Furthermore, the highest concentration of 2-naphthol was found in older children (p = 0.02), suggesting a possible difference in dietary habits. Exposure to the carbaryl insecticide is suggested based on the high concentrations of 1-naphthol (1.29 ng/mL) and considering the ratio 1-naphthol/2-naphthol (1.78). Moreover, the positive correlation between the metabolites of fluorine and pyrene also suggests exposure to PAHs by petrol combustion. The risk assessment of the PAH exposure was evaluated using the estimated daily intake (EDI) for two naphthalene metabolites in the study with a 100% detection rate. The EDI was 14.47 ng/kg BW/day. The risk assessment to the PAH exposure revealed a non-carcinogenic risk profile, with a hazard quotient of 0.71. To the best of our knowledge, this study is the first to provide levels of PAHs in Brazilian children.

Loading of Coal Tar in Polymeric Nanoparticles as a Potential Therapeutic Modality for Psoriasis

Coal tar (CT) is a commonly used therapeutic agent in psoriasis treatment. CT formulations currently in clinical use have limitations such as toxicity and skin staining properties, leading to patient nonadherence. The purpose of this study was to develop a nanoparticle (NP) formulation for CT based on biocompatible poly(lactide-co-glycolide) (PLGA). CT was entrapped in PLGA NPs by nanoprecipitation, and the resulting NPs were characterized using dynamic light scattering and high-performance liquid chromatography (HPLC) to determine the particle size and CT loading efficiency, respectively. In vitro biocompatibility of the NPs was examined in human dermal fibroblasts. Permeation, washability, and staining experiments were carried out using skin-mimetic Strat-M membranes in Franz diffusion cells. The optimal CT-loaded PLGA NPs achieved 92% loading efficiency and were 133 nm in size with a polydispersity index (PDI) of 0.10 and a zeta potential of -40 mV, promoting colloidal stability during storage. CT NPs significantly reduced the cytotoxicity of crude CT in human dermal fibroblasts, maintaining more than 75% cell viability at the highest concentration tested, whereas an equivalent concentration of CT was associated with 28% viability. Permeation studies showed that only a negligible amount of CT NPs could cross the Strat-M membrane after 24 h, with 97% of the applied dose found accumulated within the membrane. The superiority of CT NPs was further demonstrated by the notably diminished staining ability and enhanced washability compared to those of crude CT. Our findings present a promising CT nanoformulation that can overcome its limitations in the treatment of psoriasis and other skin disorders.

Aryl Hydrocarbon Receptor/nuclear factor E2-related factor 2 (AHR/NRF2) Signaling: A Novel Therapeutic Target for Atopic Dermatitis

Aryl hydrocarbon receptor (AHR)/nuclear factor-erythroid 2-related factor 2 (NRF2) modulation are emerging as novel targets in the treatment of atopic dermatitis and other inflammatory skin disorders. Agonist activation of this pathway has downstream effects on epidermal barrier function, immunomodulation, oxidative stress reduction, and cutaneous microbiome modulation. Tapinarof, a dual agonist of the AHR/NRF2 signaling pathway, has shown promise in phase 2 trials for atopic dermatitis. In this review, we summarize current knowledge of the AHR/NRF2 pathway and implications in skin disease process. We also review the therapeutic potential of current AHR agonists and propose future directions to address knowledge gaps.

Comparison Between Two Strategies of Topical Treatment in Tar Burn: A Case Report

The management of tar burns presents a wide range of possible approaches, and several strategies can be used to reduce the damage regarding the removal of tar adhered to the patient's skin. Tar residues should preferably be emulsified with solvent solutions. Due to the low incidence of tar burns, it has not yet been possible to select the appropriate agent for the removal of the adhered tar. In this article, we reported a case of a 47-year-old man with a tar burn in his forehead region and his both upper limbs treated with two different approaches and the outcomes. In the right upper limb, the removal of tar with oil-based on essential fatty acids was attempted at the time of hospital admission, whereas in the left upper limb, he was treated with 1% silver sulfadiazine cream, sterile gauze, and bandage. On the right upper limb, the treatment was eventually performed with debridement and split-thickness skin grafting. On the left upper limb, there was complete re-epithelialization of the burns. The more conservative approach of keeping a dressing with 1% silver sulfadiazine on the tar itself, followed by removing the material in the dressing changes was considered better than the immediate removal of tar with an oily solution, especially about pain. Our impression was that the application of 1% silver sulfadiazine cream at the time of the admission, as well as in the following days, may be beneficial for the removal of the tar in close contact with the skin. Possibly, this approach leads to less trauma to the skin and, eventually, simplifies the treatment of burns by hot tar.

The associations between prenatal exposure to polycyclic aromatic hydrocarbon metabolites, umbilical cord blood mitochondrial DNA copy number, and children's neurobehavioral development

Exposure to polycyclic aromatic hydrocarbons (PAHs) during pregnancy is a risk factor for adverse neurobehavioral development outcomes. Mitochondrial DNA are sensitive to environmental toxicants due to the limited ability of repairing. The change of mitochondrial DNA copy number (mtDNAcn) might be a biologically mechanism linking PAH exposure and children's neurobehavioral impairment. Our aims are to explore whether PAH metabolites in maternal urine were associated with children's neurobehavioral development at 2 years old and umbilical cord blood mtDNAcn, and whether mtDNAcn was a mediator of PAH-related neurobehavioral development. We included 158 non-smoking pregnant women from Taiyuan City, Shanxi Province. Maternal urinary eleven PAH metabolites were detected by high performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). MtDNAcn in cord blood was detected by real time quantitative polymerase chain reaction (RT-PCR). Children's neurodevelopment was measured by Gesell Developmental Schedules (GDS) when children were two years age. Generalized linear models and restricted cubic spline models were applied to assess the relationships between PAH metabolites in maternal urine and GDS scores and mtDNAcn. A mediation analysis was also conducted. Generalized linear models showed the relationships of sum of PAH metabolites (Σ-OHPAHs) in maternal urine with decreased motor score, and Σ-OHPAHs with increased mtDNAcn (p for trend < 0.05). Urinary levels of Ln (Σ-OHPAHs) increased one unit was related to a 2.08 decreased in motor scores, and Ln (Σ-OHPAHs) increased one unit was related to 0.15 increased in mtDNAcn. Mediation analysis did not find mtDNAcn can be a mediator between PAH metabolites and neurobehavioral development. Our results suggest that prenatal exposure to PAH decreased children's neurobehavioral development scores and increased mtDNAcn. And reducing exposure to PAH during pregnancy will benefit to improving neurobehavioral development in children. In our present cohort study, sum of PAH metabolites in urine of pregnant women were related with motor score and were positively associated with umbilical cord blood mtDNA copy number.

Prevalence, Incidence, and Risk of Cancer in Patients With Psoriasis and Psoriatic Arthritis: A Systematic Review and Meta-analysis

Importance

The association between psoriasis and risk of cancer remains debatable.

Objective

To evaluate the association and risk of cancer in patients with psoriasis or psoriatic arthritis, including risk of specific cancer subtypes.

Data Sources

Two databases (PubMed and Embase) were screened from inception to January 1, 2019, using the search string psoriasis or psoriatic and neoplasms or malignancy or cancer. The search was filtered to only include human participants and publications in English.

Study Selection

Observational cohort studies with a population of patients with psoriasis or psoriatic arthritis were included. Studies had to be original and report the incidence or prevalence of cancer within this population. Studies evaluating pediatric populations and cancer types not included in the protocol were excluded.

Data Extraction and Synthesis

This study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The search string, objectives, and study protocol methods were defined before the study was initiated. A total of 365 studies were included for full-text assessment. Owing to the heterogeneity of the included studies, a random-effects model was used.

Main Outcomes and Measures

Main outcome was cancer (overall and specific subtypes) and measures were prevalence, incidence, and risk estimate for cancer in patients with psoriasis or psoriatic arthritis.

Results

Of the 365 studies assessed, 112 were included in the analysis (N = 2 053 932 patients). The overall prevalence of cancer in patients with psoriasis was 4.78% (95% CI, 4.02%-5.59%), with an incidence rate of 11.75 per 1000 person-years (95% CI, 8.66-15.31) and a risk ratio (RR) of 1.21 (95% CI, 1.11-1.33). There was an increased risk of several cancers, including keratinocyte cancer (RR, 2.28; 95% CI, 1.73-3.01), lymphomas (RR, 1.56; 95% CI, 1.37-1.78), lung cancer (RR, 1.26; 95% CI, 1.13-1.40), and bladder cancer (RR, 1.12; 95% CI, 1.04-1.19). No increased risk of cancer for patients with psoriasis treated with biologic agents was found (RR, 0.97; 95% CI, 0.85-1.10). Psoriatic arthritis was not associated with increased risk of cancer overall (RR, 1.02; 95% CI, 0.97-1.08).

Conclusions and Relevance

Patients with psoriasis appear to have a slightly increased risk of cancer, particularly keratinocyte cancer and lymphomas. Data on treatment with biologic agents did not show an increased risk of cancer. Data on cancer in patients with psoriatic arthritis remain scarce, and further research is warranted in this area.

Pollution and Sun Exposure: A Deleterious Synergy. Mechanisms and Opportunities for Skin Protection

BACKGROUND

Pollutants are diverse chemical entities, including gases such as ozone and particulate matter PM. PM contains toxic chemicals such as polycyclic aromatic hydrocarbons (PAHs). Some PAHs can induce strong oxidative stress under UVA exposure. Pollution aggravates some skin diseases such as atopy or eczema, but epidemiological data also pointed to a correlation with early occurrence of (photo)-aging markers.

OBJECTIVE

This paper aims at reviewing current literature dealing with dermatological effects of pollution, either on in vitro models or using in vivo approaches (including humans). It particularly focuses on the probable deleterious synergy between pollutants and sunlight.

RESULTS

An exhaustive analysis of literature suggests that skin may be impacted by external stress through oxidation of some of its surface components. However, pollutants detected in plasma may also be provided to deep skin by the circulation of the blood. Oxidative stress, inflammation and metabolic impairments are among the most probable mechanisms of pollution- derived dermatological hazards. Moreover these stresses should be amplified by the deleterious synergy between pollution and sunlight. Some experiments from our lab identified few PAHs inducing a huge toxic stress, at nanomolar concentrations, when exposed to long UVA wavelengths. Prevention strategies should thus combine surface protection (long UVA sunscreens, antioxidants) and enhanced skin tissue resistance through stimulation of the natural antioxidation/detoxification pathway Nrf2.

CONCLUSION

In people exposed to highly polluted environments, pollutants and sunlight may synergistically damage skin, requiring a specific protection.

Importance of Dermal Absorption of Polycyclic Aromatic Hydrocarbons Derived from Barbecue Fumes

Despite the ubiquity and carcinogenicity of polycyclic aromatic hydrocarbons (PAHs), their dermal absorption for the general population has not been adequately addressed. Aiming to verify the importance of dermal absorption of PAHs, barbecue (BBQ) in Guangzhou, China was chosen as a case study. Urine samples were collected and analyzed for nine hydroxyl (OH)-PAHs. Air, food, and cotton clothing samples were analyzed for 16 PAHs. Dietary exposure was the dominant exposure route with the greatest amounts of OH-PAH excretion and PAH intake. Dermal intake of low molecular-weight PAHs was greater than inhalation intake from the occurrence of atmospheric PAHs. In addition, the net excreted amounts of OH-naphthalene, OH-fluorene, OH-phenanthrene, and OH-pyrene via dermal absorption were 367, 63, 98, and 28 ng, respectively, upon 2.5-h exposure, comparable to those via combined dermal and inhalation exposure, which were 453, 98, 126, and 38 ng. The ratios of excretion to intake via dermal absorption were 0.11, 0.036, and 0.043 for fluorene, phenanthrene, and pyrene, respectively, lower than the ratios from dietary exposure (0.38, 0.14, and 0.060) but higher than the ratios from inhalation (0.097, 0.016, and 0.025). In the case of BBQ fumes, dermal absorption was a more important pathway for intake of low molecular-weight PAHs than inhalation.

The influence of exposome on acne

BACKGROUND

Acne vulgaris is one of the main reasons for dermatological consultations. Severity and response to treatment may be impacted by various external factors or exposome.

AIM

To assess the impact of environmental factors on acne and to provide a comprehensive overview of the acne exposome.

METHODS

Two consensus meetings of five European dermatologists and a comprehensive literature search on exposome factors triggering acne served as a basis for this review.

RESULTS

Acne exposome was defined as the sum of all environmental factors influencing the occurrence, duration and severity of acne. Exposome factors impact on the response and the frequency of relapse to treatments by interacting with the skin barrier, sebaceous gland, innate immunity and cutaneous microbiota. They may be classified into the following six main categories: nutrition, psychological and lifestyle factors, occupational factors including cosmetics, as well as pollutants, medication and climatic factors. Moreover, practical considerations for the dermatologist's clinical practice are proposed.

CONCLUSION

Exposome factors including nutrition, medication, occupational factors, pollutants, climatic factors, and psychosocial and lifestyle factors may impact on the course and severity of acne and on treatment efficacy. Identifying and reducing the impact of exposome is important for an adequate acne disease management.

Review of the mechanism of action of coal tar in psoriasis

PURPOSE

Crude coal tar and its derivatives have been used in modern medicine for the treatment of psoriasis since at least 1925 as part of the Goeckerman regimen. To this day, coal tar remains a safe and highly effective option for the treatment of psoriasis vulgaris. However, the mechanism by which coal tar has its therapeutic effect is unknown. This review summarizes current knowledge of the mechanism by which coal tar has its therapeutic effect in the treatment of psoriasis vulgaris.

MATERIAL AND METHODS

A Pubmed search was conducted on March 13, 2017 for relevant English language journal articles on the subject and were relevant journal articles were included in this review.

RESULTS

Crude coal tar consists of thousands of ingredients, many of which are unidentified. Of these ingredients, the most research has gone into analyzing polycyclic aryl hydrocarbons. These hydrocarbons are thought to be the most likely component of crude coal tar that leads to its effects in psoriasis. Of the aryl hydrocarbons, carbazole has been the most well studied in psoriasis and is hypothesized as being responsible for the treatment efficacy of crude coal tar.

CONCLUSIONS

Polycyclic aryl hydrocarbons, and specifically carbazole, are thought to be the mechanism by which crude coal tar has its effect in psoriasis. However, further research is warranted to fully characterize the mechanism of action of crude coal tar, with the potential to create new therapies for psoriasis.

Arbeitsbedingte Synkanzerogenese an der Haut - Zur kombinatorischen Einwirkung zweier Karzinogene der Berufskrankheiten-Liste

HINTERGRUND

Die Synkanzerogenese am Hautorgan, wissenschaftlich unstrittig, spiegelt sich im monokausal geleiteten Berufskrankheiten (BK)-Recht nicht wider. Nichtmelanozytäre Hauttumoren und deren Vorläuferläsionen können nur nach Einzelprüfung der BK-Nrn. 5103 und 5102 anerkannt werden.

METHODIK

Retrospektive Auswertung von 28 zwischen September 2012 und September 2015 begutachteten Fällen (Altersmedian 72,5 J.) mit nichtmelanozytären Hauttumoren und deren Vorläuferläsionen und arbeitsbedingter Exposition gegenüber natürlicher UV-Strahlung und polyzyklischen aromatischen Kohlenwasserstoffen.

ERGEBNISSE

In allen 28 Fällen sahen wir die arbeitstechnischen Voraussetzungen nach den BK-Nrn. 5103 und 5102 als erfüllt an. In 26 Fällen (93 %) empfahlen wir die Hautkrebserkrankung als BK-Tatbestand nach den Nrn. 5103 und 5102 anzuerkennen. Dem folgte der Unfallversicherungsträger in vier Fällen. Achtmal wurde die Anerkennung nur nach BK-Nr. 5103, zehnmal nur nach BK-Nr. 5102 und viermal gar nicht ausgesprochen.

SCHLUSSFOLGERUNGEN

Bei nichtmelanozytären Hauttumoren oder deren Vorläuferläsionen an UV-exponierten Hautarealen mit ausreichend kumulativer arbeitsbedingter natürlicher UV-Strahlenexposition und bei arbeitsbedingter Exposition gegenüber polyzyklischen aromatischen Kohlenwasserstoffen sollten mittels BK-Anzeige die "BK-Nrn. 5103 und 5102 im Sinne der Synkanzerogenese" gemeldet werden. Neben der gerechteren Wiedergabe der Arbeitsplatzrealitäten in einem solchen Feststellungsverfahren kann es dann im Konkreten auch zur Anerkennung von Basalzellkarzinomen kommen, die ansonsten, bei alleiniger Prüfung der BK-Nr. 5103, herausgerechnet würden.

Evaluation of 11 polycyclic aromatic hydrocarbon metabolites in urine of Czech mothers and newborns

Polycyclic aromatic hydrocarbons (PAHs) represent a large group of ubiquitous contaminants of the environment, including food chain where they are released as by-products of incomplete combustion of an organic matter. Epidemiological studies have shown that exposure to PAHs correlated with increased incidence of cancer. Carcinogenicity is associated mainly with metabolites that are formed during metabolic degradation of these substances in exposed organism. In this study monohydroxylated PAHs (OH-PAHs), the major metabolites excreted into urine, were determined in 531 urine samples collected from mothers and their newborns from two localities of the Czech Republic - heavily air polluted Karvina and control locality of Ceske Budejovice and in two sampling rounds - August-October 2013 (summer, less air polluted season) and January-April 2014 (winter, more air polluted season). From all targeted analytes, naphthalene-2-ol was the most abundant compound present in 100% of the samples and it represented also the analyte with the highest concentration. Median concentration of ΣOH-PAHs in the urine of children was on average 1.6 times lower compared to the respective mother which correlates with higher intake of PAHs by mothers. ΣOH-PAHs concentrations determined in mothers' urine collected in the summer were comparable in both localities. No significant increase occurred in Ceske Budejovice in winter, while in samples from the Karvina region a statistically significant difference (α=0.05) in the amount of ΣOH-PAHs was observed. The median concentrations of ΣOH-PAHs in mothers' urine samples in the winter were 1.5 times higher than in the summer in the same locality. The amounts of ΣOH-PAHs in newborns' urine from Karvina in the winter season were 1.5 times higher than in the summer collected in the same locality and 3.3 times higher when compared with the less polluted locality of Ceske Budejovice.

Relationship between atmospheric pollution in the residential area and concentrations of polycyclic aromatic hydrocarbons (PAHs) in human breast milk

Human milk is an important source of beneficial nutrients and antibodies for newborns and infants and, under certain circumstances, its analysis may provide information on mothers' and infants' exposure to various contaminants. In the presented study, we have introduced the new analytical approach for analysis of 24 highly occurring polycyclic aromatic hydrocarbons (PAHs) in this indicator matrix. The sample preparation procedure is based on an ethyl acetate extraction of milk; the transfer of analytes into an organic layer is enhanced by addition of inorganic salts, i.e. sodium chloride and magnesium sulphate. Following the clean-up of a crude extract on silica SPE columns, gas chromatography coupled to triple quadrupole mass spectrometry is used for PAH identification and quantitation. The average recoveries of targeted PAHs from spiked samples were in the range of 68-110% with repeatabilities below 30% and method quantitation limits ranging from 0.03 to 0.3ng/g lipid weight. This newly validated method was successfully applied for analyses of 324 human milk samples collected from nonsmoking women during two sampling periods (summer and winter) in two residential areas in the Czech Republic differing in atmospheric pollution by PAHs. From 24 targeted analytes 17 were detected at least in one sample. Phenantherene, fluoranthrene, pyrene and fluorene were the most abundant compounds found at average concentration of 13.81, 1.80, 0.86, and 2.01ng/g lipid weight respectively. Comparing the data from two sampling periods, in both areas higher concentrations were measured in samples collected during winter. Also in the highly industrialized locality with heavily contaminated air PAH amounts in milk were higher than in the control locality. These first data on PAH concentrations in human milk collected in the Czech Republic are comparable with measurements for nonsmoking women reported earlier in the United States but significantly lower than results from China, Turkey or Italy.