Hydrocarbon solvents are liquid hydrocarbon fractions derived from petroleum processing streams, containing only carbon and hydrogen atoms, with carbon numbers ranging from approximately C5-C20 and boiling between approximately 35-370°C. Many of the hydrocarbon solvents have complex and variable compositions with constituents of 4 types, alkanes (normal paraffins, isoparaffins, and cycloparaffins) and aromatics (primarily alkylated one-and tworing species). Because of the compositional complexity, hydrocarbon solvents are now identified by a nomenclature ("the naming convention") that describes them in terms of physical/ chemical properties and compositional elements. Despite the compositional complexity, most hydrocarbon solvent constituents have similar toxicological properties, and the overall toxicological hazards can be characterized in generic terms. To facilitate hazard characterization, the solvents were divided into 9 groups (categories) of substances with similar physical and chemical properties. Hydrocarbon solvents can cause chemical pneumonitis if aspirated into the lung, and those that are volatile can cause acute CNS effects and/or ocular and respiratory irritation at exposure levels exceeding occupational recommendations. Otherwise, there are few toxicologically important effects. The exceptions, n-hexane and naphthalene, have unique toxicological properties, and those solvents containing constituents for which classification is required under the Globally Harmonized System (GHS) are differentiated by the substance names. Toxicological information from studies of representative substances was used to fulfill REACH registration requirements and to satisfy the needs of the OECD High Production Volume (HPV) initiative. As shown in the examples provided, the hazard characterization data can be used for hazard classification and for occupational exposure limit recommendations. Introduction Scope and purpose of the documentThe present document summarizes information on the physical/ chemical properties and toxicological hazards of hydrocarbon solvents and provides examples of the ways in which the information on hazard characterization can be used for hazard classification and to set occupational exposure limits. Many of the toxicological studies were published separately, but the results are summarized herein and referenced in the appendices.Hydrocarbon solvents are liquid hydrocarbon fractions that are primarily produced by the distillation of petroleum feed stocks or their synthetic analogs (e.g., Fischer-Tropsch derived materials), sometimes followed by additional processing steps such as solvent extraction, hydrodesulfurization, or hydrogenation. 1 Most hydrocarbon solvents are complex substances with variable compositions and are best described as UVCB 2 (unknown and variable composition) substances, but some are single constituent (mono-constituent) substances. The complex and variable nature of these solvents is the consequence of their manufacturing processes. In short, most hydroca...

No abstract

To explore the effects of increasing fruit and vegetable intake and the resulting effects on levels of circulating micronutrients in a community-dwelling population with an already high consumption of fruits and vegetables, 112 volunteers (86% women) underwent targeted dietary counseling for three months. At the beginning of the study and after 4, 8 and 12 weeks a food frequency questionnaire was filled in, and plasma levels of dietary antioxidants as well as biomarkers of oxidative lipid and protein damage were determined. Compared to baseline, especially the intake of fruits was significantly improved after 3 months of intervention, and mean plasma levels of lutein, zeaxanthin, β-cryptoxanthin, lycopene, α-and β-carotene, retinol, α-tocopherol, vitamin C and vitamin B6 were increased. Biomarkers of oxidative stress remained unchanged. Thus, a nutritional counseling program is capable of improving plasma levels of antioxidants even in a health-conscious population. A decrease in biomarkers of oxidative stress, however, does not occur. FindingsDietary habits are an important instrument of active care for maintaining the population's health due to the association between antioxidant-rich food intake and the occurrence of age-related diseases [1]. A large part of the population, however, does not meet the recommended daily intake of five portions of fruits and vegetables http:/ /www.5aday.com. Research is still needed on micronutrient requirements for optimal health and adequate vitamin intake. Identification of the conditions favoring initiation and maintenance of a healthy nutrition, especially so in adult working populations as target groups of preventive activities, has become a major health priority.One-hundred twenty-nine employees of a University Hospital in Düsseldorf, Germany, were recruited in the present study. All study participants gave their informed signed consent and followed an intervention plan consisting of 4 two-hour sessions for three months: baseline, T0; 4 weeks, T1; 8 weeks, T2; and 12 weeks, T3. In the sessions, guided by a nutritionist and a physician, participants were motivated to consume at least five portions of

No abstract

Gas-to-liquid (GTL) products are synthetic hydrocarbons produced from natural gas using a Fischer-Tropsch process. This process yields a synthetic crude oil that consists of saturated hydrocarbons, primarily linear alkanes, with increasing amounts of branched (methyl-groups) alkanes as the chains get longer. In addition, small amounts of cycloalkanes (branched cyclopentanes and cyclohexanes) may be formed as the polymerization reaction prolongs. This synthetic crude can subsequently be refined to a range of products very similar to petroleum refining. However, in contrast to their petroleum-derived analogs, GTL products are essentially free of unsaturated or aromatic constituents and also no sulfur-, oxygen-, or nitrogen-containing constituents are present. From a regulatory perspective, GTL products are new substances which require extensive testing to assess their hazardous properties. As a consequence, a wide range of GTL products, covering the entire portfolio of GTL products, have been tested over the past few years in a wide variety of toxicological studies, including reproductive and prenatal development toxicity studies. This review provides an overview of the hazardous properties of the various GTL products. In general, the data collected on GTL products provide strong proof that they exert minimal health effects. In addition, these data provide supporting evidence for what is known on the mechanisms of mammalian toxicology of their petroleum-derived analogs. In the few cases where adverse effects were found for the GTL substances, these were usually less severe than the adverse effects observed with their petroleum-derived analogs.