Über röntgenographische Untersuchungen des Gel-Zustandes beim Abbindevorgang von Gips

The Science of Nature -     

Poly- and perfluorinated compounds in household consumer products

Several household consumer products were analyzed for their content of perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), and fluorotelomer alcohols (FTOH) by nanoflow ultra performance liquid chromatography – mass spectrometry and gas chromatography – mass spectrometry. Among the investigated products, which are applied as sprays, were impregnating agents, cleaning agents, lubricants, and conditioners. In 14 of the 26 products analyzed, at least one polyfluorinated compound (PFC) was detected in 14 samples. 8?:?2 FTOH was the dominating PFC with concentrations up to 149?µg?mL^?1. The maximum concentration of PFOA was 14.5?µg?mL^?1, whereas PFOS was not detected in any sample. Investigated PFCs were mostly found in impregnating agents and lubricants, but were not detected in cleaning agents and conditioners. In FTOH-containing impregnating agents, similar ratios between 6?:?2 FTOH, 8?:?2 FTOH, and 10?:?2 FTOH were found. FTOH proportions in PFC-containing lubricants were similar as well. Total human exposure to PFC from consumer product aerosols for three different scenarios was estimated to be between 42.8 and 464?ng?kg^?1?per day.     

Alkoxy-silyl Induced Agglomeration: A New Approach for the Sustainable Removal of Microplastic from Aquatic Systems

The substance class of inert organic-chemical stressors (IOCS) describes organic-chemical (macro-) molecules, which demonstrate a high level of persistence upon entry in the ecosystem, and whose degradation is limited. These synthetically produced organic-chemical macromolecules, which are often derived from the polymerization of different monomers, are, in the form of plastics, indispensable in the everyday world. They enter the environmental compartments and cause great damage due to primary (industry, cosmetic, washing of textile), and secondary (degradation) entry. If these particles get into aquatic systems, this has fatal consequences for the ecosystem such as the death of marine animals, or bioaccumulation. Wastewater treatment plants are reaching their limits and require innovative ideas for the sustainable removal of microplastic. This article examines a new approach to the removal of polymers from aquatic systems (lab scale) by using sol–gel induced agglomeration reactions to form larger particle agglomerates. These enlarged agglomerates can be separated much more easily from the wastewater, since they float on the water surface. Separation systems, e.g. sand trap can easily be used. A further advantage is that the agglomeration can be carried out completely independently of the type, size, and amount of the trace substance concentration as well as of the external influences (pH value, temperature, pressure). Thus, this new type of particle separation can not only be used in sewage treatment plants, but can also be transferred to decentralized systems (e.g. implementation in industrial processes).

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Globaler Vertrag zur Regelung von POPs: Die Stockholm Konvention

The success of the negotiations on the POPs Convention after the failure of the negotiations over the climate protocol in The Hague in late November is an important result for international action to protect the earth from damage by chemicals. It shows the countries’ real commitment to find compromises for protection of the environment and human health and for the restoration of damaged ecosystems on our planet. It deserves to be highlighted that all participants — not only the industrialized countries but also developing countries as well as environmental organizations and the (chemical) industry — regard the conclusion of this convention as a success and that a broad basis for joint action has thus been created. The convention is a signal also because of its useful contents, which includes instruments for the total elimination of 12 POPs in the beginning and of further persistent organic pollutants at a later stage. The basis for a gradual reduction of the increasing pollution of the environment on a global scale is given by mechanisms for subjecting further POPs to the requirements of this Convention in the future.     

Dioxins (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-furans) in traditional clay products used during pregnancy

Geophagy, the practice of consuming clay or soil, is encountered among pregnant women in Africa, Eastern Asia and Latin America, but also in Western societies. However, certain types of clay are known to contain high concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). The aim of this study was to determine the PCDD/F contents of orally consumed clays purchased from Dutch and African markets. Congener patterns were compared with those of pooled human milk samples collected in eight African countries, to investigate a possible relationship with clay consumption. From the Dutch market thirteen clay products were examined, seven of African and six of Suriname origin. From seven African countries, twenty clay products were collected. All 33 clay products were screened with a cell-based bioassay and those showing a high response were analyzed by GC/HRMS. High PCDD/F concentrations were measured in three clay products from the Dutch market, ranging from 66 to 103 pg TEQ g^-1, whereas clay products from African countries were from 24 to 75 pg TEQ g^-1. Patterns and relatively high concentrations of PCDD/Fs in human milk samples from the Democratic Republic of the Congo and Côte d’Ivoire suggest a relationship with the consumption of contaminated clay. Frequent use of PCDD/F contaminated clay products during pregnancy may result in increased exposure of the mother and subsequently the developing fetus and new-born child. The use of these contaminated clays during pregnancy should be carefully considered or even discouraged.