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Coal Tar (coal + tar)

Distribution by Scientific Domains

Medical Sciences	50%
Life Sciences	43%

Selected Abstracts

Partition Behavior of Polycyclic Aromatic Hydrocarbons Between Aged Coal Tar and Water,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2009
Lihua Liu
Abstract Coal tar aged in a large-scale, artificial aquifer experiment for five years was subsequently investigated for leaching behavior of polycyclic aromatic hydrocarbons (PAHs). After five years, the initially liquid coal tar had solidified and formed segregated particles with a grain size similar to that of the sandy aquifer material. The composition of the aged coal tar (ACT) with regard to PAHs was remarkably different from that of the original bulk coal tar (BCT), because most of the low-molecular-weight compounds had been depleted. Equilibrium aqueous-phase concentrations of 17 PAHs leaching from the aquifer material containing the ACT were measured from consecutive equilibration steps at increasing temperatures of between 25 and 100C using accelerated solvent extraction. The results showed 2-to 5,000-fold lower concentrations than those from BCT, indicating dramatic changes of dissolution behavior of PAHs from coal tar after the five-year aging period. Predictions based on Raoult's law with the subcooled liquid solubilities substantially overestimated the equilibrium aqueous-phase concentrations of the PAHs from ACT, whereas the estimations were reasonable if the solid solubilities were employed instead. The enthalpies of phase transfer from ACT to water were determined based on the van't Hoff equation. The resulting values agreed with the dissolution enthalpies of pure solid rather than subcooled liquid PAHs. [source]

Uptake of Pyrene in a Breast-Fed Child of a Mother Treated with Coal Tar

PEDIATRIC DERMATOLOGY, Issue 2 2009
Paul T. J. Scheepers Ph.D.
Coal tar containing ointments contain genotoxic polycyclic aromatic hydrocarbons. Over a period of 50 days the accumulated dose of different coal tar containing ointments treatments corresponded to 993 mg of pyrene and 464 mg of benz[a]pyrene. During this treatment she gave breast milk to her 3-month-old daughter. Analysis of urine samples from the breast-fed child showed elevated levels of urinary excretion of a metabolite of pyrene (1-hydroxypyrene, 1-OHP). These levels were in the same range as urinary excretion levels of this metabolite observed in the mother's urine. As no pyrene was observed in breast milk at a limit of determination of 0.0035 ,mol/L, transfer of pyrene from mother to child via breast milk is not likely. Also, a low level of 1-hydroxypyrene observed in the mother's milk did not account for the observed urinary excretion levels in the child. It must therefore be assumed that pyrene was transferred from mother to child via another route, presumably direct skin-to-skin or skin-to-mouth contact. Dermatologists should inform their patients who receive treatment with coal tar containing ointments of the risk of transfer of polycyclic aromatic hydrocarbons by skin-to-skin or skin-to-mouth contact. [source]

Partition Behavior of Polycyclic Aromatic Hydrocarbons Between Aged Coal Tar and Water,

Effect of artificial mixtures of environmental polycyclic aromatic hydrocarbons present in coal tar, urban dust, and diesel exhaust particulates on MCF-7 cells in culture

ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 2 2004
Brinda Mahadevan
Abstract Human exposure to polycyclic aromatic hydrocarbons (PAHs) occurs through complex mixtures. The National Institute of Standards and Technology has established standard reference materials (SRMs) for selected PAH mixtures that are composed of carcinogenic, noncarcinogenic, and weakly carcinogenic compounds, such as those derived from coal tar (SRM 1597), atmospheric particulate matter (SRM 1649), and diesel particulate matter (SRM 1650). To study the effects of PAHs with different carcinogenic potential in complex mixtures, and to investigate the metabolic activation of noncarcinogenic and weakly carcinogenic PAHs to DNA-binding derivatives, artificial mixtures (1597H, 1649H, and 1650H) were prepared in the laboratory. These artificial mixtures contained the same relative ratios of noncarcinogenic and weakly carcinogenic PAHs present in SRM 1597, SRM 1649, and SRM 1650. The human mammary carcinoma-derived cell line MCF-7 was treated with these artificial mixtures and analyzed for PAH-DNA adduct formation and the induction of cytochrome P450 (CYP) enzymes. We found that the artificial mixtures formed lower but detectable levels of DNA adducts 24 and 48 hr after treatment than benzo[a]pyrene. Induction of CYP enzyme activity was measured by the ethoxyresorufin- O -deethylase assay, and the expression of CYP1A1 and CYP1B1 was confirmed by immunoblots. Both noncarcinogenic and weakly carcinogenic PAHs present in the artificial mixtures have the ability to induce CYP1A1 and CYP1B1 in MCF-7 cells and contribute to DNA binding. Therefore, it is necessary to take into account the noncarcinogenic and weakly carcinogenic PAHs present in environmental mixtures in assessing the potential risk associated with human exposure. Environ. Mol. Mutagen. 44:99,107, 2004. © 2004 Wiley-Liss, Inc. [source]

Partition Behavior of Polycyclic Aromatic Hydrocarbons Between Aged Coal Tar and Water,

Bench-scale evaluation of in situ bioremediation strategies for soil at a former manufactured gas plant site

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2005
Jun Li
Abstract We examined the biodegradation and desorption of a set of 15 polycyclic aromatic hydrocarbon (PAH) compounds in coal tar,contaminated soil at a former manufactured gas plant site to evaluate the feasibility of in situ bioremediation. Experiments were conducted in well-mixed aerobic soil suspensions containing various additives over a 93- to 106-d period. In general, both biotransformation and desorption decreased with PAH ring size, becoming negligible for the six-ring PAH compounds. Biodegradation by indigenous microorganisms was strongly accelerated by addition of inorganic nutrients (N, P, K, and trace metals). The rates of biotransformation of PAH compounds by indigenous microorganisms in nutrient-amended flasks outpaced their maximum (i.e., chelate-enhanced) rates of desorption to an infinite sink (Tenax®) in sterilized systems run in parallel, suggesting that indigenous organisms facilitated desorption. Biodegradation by indigenous organisms in nutrient-amended flasks appeared to be unaffected by the addition of a site-derived bacterial enrichment culture, resulting in approximately 100-fold higher aromatic dioxygenase levels, and by the addition of 0.01 M chelating agent (citrate or pyrophosphate), although such chelating agents greatly enhanced desorption in microbially inactivated flasks. The strong ability of nutrients to enhance degradation of the bioavailable PAHs indicates that their persistence for many decades at this site likely results from nutrient-limited natural biodegradation, and it also suggests that an effective strategy for their bioremediation could consist simply of adding inorganic nutrients. [source]

Myeloperoxidase (MPO) genotype and lung cancer histologic types: The MPO ,463 A allele is associated with reduced risk for small cell lung cancer in smokers

INTERNATIONAL JOURNAL OF CANCER, Issue 5 2002
Heike Dally
Abstract MPO participates in the metabolic activation of tobacco carcinogens such as PAHs. A frequent MPO ,463 G,A polymorphism in the promoter region reduces MPO transcription and has been correlated with >4-fold lower benzo[a]pyrene,DNA adduct levels in the skin of coal tar,treated patients. Four of 7 case-control studies found significantly reduced lung cancer risk associated with the A allele. Due to their different etiologies, we examined whether the MPO genotype affects histologic lung cancer types differentially. A case-control study was conducted in 625 ever-smoking lung cancer patients, including 228 adenocarcinomas, 224 SCCs, 135 SCLCs and 340 ever-smoking hospital controls. MPO genotyping was performed by capillary PCR followed by fluorescence-based melting curve analysis. Combining the MPO ,463 (G/A+A/A) genotypes, a protective effect approaching significance (OR = 0.75, 95% CI 0.55,1.01) was observed when comparing all lung cancer cases to controls. Among histologic types of lung cancer, a weak protective effect was found for both adenocarcinoma (OR = 0.81, CI 0.55,1.19) and SCC (OR = 0.82, CI 0.56,1.21); a stronger and significant effect was found for SCLC (OR = 0.58, CI 0.36,0.95; p = 0.029). Our results also suggest that the MPO genotype varies among inflammatory nonmalignant lung diseases. In conclusion, our results emphasize the need for a separate analysis of lung cancer histologic types and an adjustment for inflammatory nonmalignant lung diseases in future MPO-related studies. We confirm that the MPO ,463 A variant affords a protective effect against lung cancer risk in smokers, which was strongest for SCLC patients. © 2002 Wiley-Liss, Inc. [source]

Hereditary palmoplantar keratoderma (four cases in three generations)

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 2 2001
Virendra N. Sehgal MD
A 39-year-old man reported with progressive thickening of the skin of the hands and feet and an inability to flex his hand. It was largely asymptomatic; however, brisk walking caused excessive sweating, pain, and widening of the fissures on the soles of the feet. He was unable to walk barefooted. According to his mother, the first episode presented with blistering at 7 days of age. Ever since, the condition has steadily worsened to acquire the current status. He was married at the age of 18 years, and had a stillborn child 18 months afterwards. Presently, he has three children, two girls aged 14 and 12 years and a son aged 10 years. Both the daughters are similarly affected. While cataloguing the details of the pattern of inheritance, the mother of the index case was also found to be affected (Fig. 1). The natural history of the disease was identical. Figure 1. Palmoplantar keratoderma: pattern of inheritance; black indicates affected individuals Examination of the palms was marked by pronounced thickening of the skin resulting in the masking of palmar creases. The thickening was well demarcated and its margins were prominent and surrounded by an erythematous halo. The color of the skin was yellow and waxy (Fig. 2a). Contractures were present on all the fingers; nevertheless, the deformity of the middle and distal interphalangeal joints of the little finger was prominent. The soles of the feet had a similar morphology. In addition, marked fissuring was obvious (Fig. 2b). His daughters had an identical affliction of the palms and soles. The texture and morphology of the nails were normal. Light microscopy performed on scrapings from the fissures, mounted on 10% potassium hydroxide, revealed mycelia (hyphae) and spores. Figure 2. Well-demarcated hyperkeratosis depicting the yellow, waxy color of the palms, with masking of creases (a). Marked fissuring on the soles was prominent (b) Hematoxylin and eosin-stained microsections from the palms and soles showed exquisite changes in the epidermis characterized by considerable uniform orthohyperkeratosis. Hypergranulosis and acanthosis were other associated changes. In addition, perinuclear vacuolization and keratohyalin granules of varying sizes and shapes were located at the periphery of the cells. A sparse mononuclear infiltrate was located at the dermo-epidermal junction. Hyphae and spores of fungi were also identified in the stratum corneum (Fig. 3). Figure 3. Orthohyperkeratosis, hypergranulosis, and acanthosis. Perinuclear vacuolization and keratohyalin granules at the periphery of the cells; a sparse mononuclear infiltrate was also present (hematoxylin and eosin, ×,40 (a), ×,400 (b)) Itraconazole, 400 mg/day in two equally divided doses, was administered with major meals for 7 days. In addition, high doses of vitamin A (100,000 IU) were given daily for 2 weeks, supplemented by 12% salicylic acid (Salicylix SF12) ointment for daytime application and an ointment containing 6% coal tar and 3% salicylic acid (Salytar) for night-time application. This treatment is useful in recalcitrant cases. [source]

A novel LCD (coal tar) solution for psoriasis does not discolor naturally light or color-processed hair in an exaggerated exposure test model

JOURNAL OF COSMETIC DERMATOLOGY, Issue 3 2009
Colleen Johnson BS
Summary Background, Scalp psoriasis is reported to occur in 50,80% of psoriasis sufferers. Treatment of scalp psoriasis requires special consideration of product esthetics and staining potential due to the presence of hair. Aim, To evaluate the potential of a new, marketed liquor carbonis distillate (LCD; coal tar) solution to discolor naturally light or color-processed hair under exaggerated exposure conditions. Methods, Samples of naturally light and color-processed hair from a single donor were exposed to LCD solution repeatedly over 14 days and via submergence for 24 h. Color of LCD-treated hair samples was compared with untreated control hair samples. Results, LCD solution did not discolor naturally light or color-processed hair following repeated exposures and 24 h submergence. Conclusion, The marketed LCD solution does not appear to discolor naturally light or color-processed hair. [source]

Immunologic Changes in TNF-alpha, sE-selectin, sP-selectin, sICAM-1, and IL-8 in Pediatric Patients Treated for Psoriasis with the Goeckerman Regimen

PEDIATRIC DERMATOLOGY, Issue 6 2007
Lenka Borska M.D., Ph.D.
The present study investigated changes in the serum levels of proinflammatory cytokines and soluble forms of adhesion molecules in children with psoriasis. The observed patient group of 26 children was treated with the Goeckerman regimen. This therapy combines dermal application of crude coal tar with ultraviolet radiation. The Psoriasis Area Severity Index decreased significantly after treatment by with the Goeckerman regimen (p < 0.001). Serum levels of the proinflammatory cytokine TNF-alpha and adhesion molecules sICAM-1, sP-selectin and sE-selectin decreased after the Goeckerman regimen. The TNF-alpha and sICAM-1 decreased significantly (p < 0.05). Our findings support the complex role of these immune parameters in the immunopathogenesis of psoriasis in children. The serum level of IL-8 increased after the Goeckerman regimen. This fact indicates that the chemokine pathway of IL-8 activity could be modulated by this treatment, most likely by polycyclic aromatic hydrocarbons. [source]

Estimating exposures in the asphalt industry for an international epidemiological cohort study of cancer risk

AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 1 2003
Igor Burstyn
Abstract Background An exposure matrix (EM) for known and suspected carcinogens was required for a multicenter international cohort study of cancer risk and bitumen among asphalt workers. Methods Production characteristics in companies enrolled in the study were ascertained through use of a company questionnaire (CQ). Exposures to coal tar, bitumen fume, organic vapor, polycyclic aromatic hydrocarbons, diesel fume, silica, and asbestos were assessed semi-quantitatively using information from CQs, expert judgment, and statistical models. Exposures of road paving workers to bitumen fume, organic vapor, and benzo(a)pyrene were estimated quantitatively by applying regression models, based on monitoring data, to exposure scenarios identified by the CQs. Results Exposures estimates were derived for 217 companies enrolled in the cohort, plus the Swedish asphalt paving industry in general. Most companies were engaged in road paving and asphalt mixing, but some also participated in general construction and roofing. Coal tar use was most common in Denmark and The Netherlands, but the practice is now obsolete. Quantitative estimates of exposure to bitumen fume, organic vapor, and benzo(a)pyrene for pavers, and semi-quantitative estimates of exposure to these agents among all subjects were strongly correlated. Semi-quantitative estimates of exposure to bitumen fume and coal tar exposures were only moderately correlated. EM assessed non-monotonic historical decrease in exposures to all agents assessed except silica and diesel exhaust. Conclusions We produced a data-driven EM using methodology that can be adapted for other multicenter studies. Am. J. Ind. Med. 43:3,17, 2003. © 2003 Wiley-Liss, Inc. [source]

Contributions of common sources of polycyclic aromatic hydrocarbons to soil contamination

REMEDIATION, Issue 3 2006
John A. Simon
Asphalt products, particularly sealants, are prepared using petroleum products that contain a com-plex mixture of aliphatic and aromatic hydrocarbons, including polycyclic aromatic hydrocarbons (PAHs). Clearly, these products are ubiquitous in urban environments, which raises an issue regard-ing the potential for PAHs to be transported from parking lots to underlying or adjacent soil, surface-water bodies, or groundwater. Based on a literature review, there are limited studies focus-ing on this issue; however, the studies that have been published have fascinating conclusions. The literature shows, as expected, that asphalt-based products contain PAHs. The highest PAH concen-trations are present in asphalt sealants, particularly those manufactured using coal tar. Furthermore, due to the low solubility and high partition coefficients of PAHs, the potential for PAHs to leach from asphalt surfaces is negligible, which has been confirmed by leachability studies. Thus, there is little risk that PAHs will be present in stormwater runoff or leach into groundwater from asphalt-paved areas in a dissolved form. However, asphalt pavement and sealants produce particulate matter that can contain concentrations of PAHs in the sub-percent range (100s to 1,000s mg/kg total PAHs) that is transported in stormwater runoff. Some studies show that this can cause soil and sediment con-tamination with total PAH concentrations in the range of 1 to 10 mg/kg. From a remediation per-spective, many site cleanups are conducted to remediate the presence of PAHs to cleanup goals below 1 mg/kg or, in some cases, 0.1 mg/kg or lower. From a total risk perspective, remediating sites to low PAH cleanup goals may be unwarranted in light of the risk of transportable PAHs produced from paved parking surfaces. In other words, is it reasonable to conduct a cleanup to remediate low PAH concentrations and then redevelop the area with asphalt pavement and sealant, which may pose a greater PAH-related risk? © 2006 Wiley Periodicals, Inc. [source]

A double blind, randomized, controlled clinical trial to assess the efficacy of a new coal tar preparation (Exorex) in the treatment of chronic, plaque type psoriasis

CLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 8 2000
C. H. Smith
Exorex is a new topical formulation for the treatment of psoriasis; it contains 1% coal tar and a synthetic analogue resembling components identified in banana skin (a complex of esterified essential fatty acids). To determine whether the esterified essential fatty acid complex confers any therapeutic advantage over coal tar alone, patients with chronic plaque psoriasis (n = 20) were entered into a double-blind, randomized, right/left comparison of Exorex, and Exorex without the essential fatty acid component (known hereafter as coal tar control) for 8 weeks. Target plaques were scored (0,4) for erythema, desquamation and infiltration at day 0 and at 2 week intervals throughout the study. No significant differences were detected between Exorex and coal tar control with respect to changes in the summed scores at baseline and following 8 weeks of treatment (mean difference in summed score changes from baseline between Exorex and coal tar control 0.2, 95% confidence interval ,,0.44 to 0.84; P = 0.52) or in the area under the response,time curve (P = 0.16). Mean percentage improvement in summed scores of target plaques were 53.9% (SE = 4%) and 56.1% (SE = 4.9%) for Exorex and coal tar control, respectively. Results suggest that the complex of esterified essential fatty acids is not exerting any clinically important therapeutic effect in the treatment of chronic plaque psoriasis. [source]