Suchergebnisse

Die Ausweitung des Evolutionsgedankens auf alle Wissenschaftsbereiche beschäftigte den Tübinger Professor schon in 'Entdeckung der Evolution'. Im 'Darwin-Code' geht es ihm nun zusammen mit der Biologin und Wissenschaftspublizistin Paul um die evolutionsbiologische Deutung der Kultur. Allgemein verständlich erläutern die Autoren die Fehlanpassungshypothese, die besagt, dass der Mensch mit seinen im Laufe von 2 Millionen Jahren entwickelten Genen beispielsweise einem in den letzten 150 Jahren drastisch veränderten Nahrungsmittelangebot gegenübersteht. In einem weiteren Kapitel geht es um die Herleitung der Kunst als eine spezielle Art der Kommunikation, die als erweitertes Ich durchaus Rückschlüsse auf die Gene des Urhebers zulässt. Breit einsetzbare Lektüre über die menschlichen Verhaltensweisen aus evolutionsbiologischer Sicht. (1) STO klein

AbstractBecause of their usually high molecular weight, polymers are generally considered as being of low environmental concern and are, therefore, exempted from registration and evaluation within REACH. This exemption is currently being reviewed by the European Commission. Against this background, data on the environmental fate and effects of selected water-soluble synthetic organic polymers used in cosmetic products were evaluated. The considered polymers include non-ionic polyethylene glycols (PEGs), anionic homo- and copolymers of acrylic acid (AA-P&CoPs), and cationic polyquaterniums (PQs). The PEGs are more amenable to biodegradation than the AA-P&CoPs and the PQs, which biodegrade slowly. In wastewater treatment plants, sorption and precipitation are expected to lead to an effective removal of the considered polymers from the wastewater. Uptake and bioaccumulation in aquatic organisms are limited by the large molecular size and, for AA-P&CoPs and PQs, the ionic charge of the polymers. In aquatic ecotoxicity tests, the PEGs and the AA-P&CoPs showed generally no to low toxicity. Effects of AA-P&CoPs on algae and crustaceans are attributed to the chelation of cationic nutrients in soft water, with toxicity being mitigated at higher water hardness. Toxicity of the cationic PQs to aquatic organisms ranged from absent to high, depending on the polymer structure, charge density and molecular weight, as well as on the test organism and test conditions. The observed effects most likely result from interactions with the organisms' surfaces. Aquatic toxicity of the PQs is reduced by dissolved organic carbon, suspended solids, sediments minerals, and at higher water hardness, representative of natural conditions. Results from toxicity tests with sediment and soil organisms were only identified for homopolymers of acrylic acid, showing no toxicity. The evaluation of the available ecotoxicity data suggests that test methods may need to be adapted to the respective polymer type, and further standardised to improve reproducibility. Based on the identified data, the considered polymers are likely to be of low environmental concern. However, this conclusion must be seen as preliminary, since environmental concentrations could not be estimated, and further ecotoxicity data are required, e.g., for sediment and soil organisms.

Ready biodegradability tests (RBTs) of the OECD 301 series and the OECD 310 are currently used for testing of ready biodegradability and for the identification of potentially persistent substances. The project aimed giving recommendations for further development and standardization of these tests next to improve knowledge about the application of so called "enhanced" ready tests (eRBT), where a longer test duration up to 60 d and larger vessel volumes are allowed. A survey among European laboratories was performed, to identify their experiences with ready biodegradability testing. The results were discussed among experts on an international workshop in April 2019. Further on, a practical testing programme has been realised with five test compounds in 4 testing series under different conditions. Here, Ibuprofen and 4-Fluorophenol were regarded as being non-persistent while the results for Piperonylbutoxide were inconclusive ("potentially P"). Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate did not meet the 60% pass level in any test series and thus also is "potentially P". Cis-13-Docosenonamide (Erucamide) can be considered as being non-persistent based on results from several tests, but some doubts remain, since a high variability between replicates was observed. The testing experience led to suggestions regarding the test design, the evaluation and the interpretation of eRBTs, which could be used as a starting point for further guidance. The impact of the proposed recommendations for the persistence assessment under REACH are discussed.

Abstract
Background
Spreading of manure on agricultural soils represents an important pathway by which veterinary medicinal and biocidal products enter the environment. To assess their environmental impact in the context of authorization processes, experimental testing of transformation of these compounds in manure is considered in regulatory guidance documents. However, there is no standardized experimental test method available so far. To fill this gap, an experimental test method was developed to examine transformation in liquid cattle and pig manure.

Results
To account for manure specifics and for a possible influence of manure parameters on transformation rates, a comprehensive data acquisition and statistical analysis were performed. To address the variability of liquid manure of different type and origin, 30 manures were sampled and characterized. Thereof, three cattle and three pig manures were selected to perform anaerobic transformation studies with two radiolabeled veterinary medicinal active substances (14C-salicylic acid and 14C-paracetamol) and a confidential radiolabeled "14C-biocide B" serving as test compounds. Spatial and seasonal variability of manure parameters was quantified, and a sampling technique to obtain homogenous manure samples was developed. Transformation studies with six replicates per sampling point were conducted to examine the influence of test setup, of manure storage conditions, and of parameter variations between manure of the same species and of different species on half-lives, formation of extractable and non-extractable residues and mineralization rates. Finally, a test design was established that yields reproducible results for transformation studies in liquid cattle and pig manure under anaerobic conditions.

Conclusions
Results give a reliable basis for an experimental test method to perform anaerobic transformation studies in liquid cattle and pig manure. The developed test method comprises detailed guidance on selection of sampling date and site, collection from manure tank, storage duration and temperature in the laboratory, duration of manure acclimation period, and the incubation system design. It proved to give reproducible results in a validation ring test performed in a follow-up project and is planned to be submitted as draft test guideline for approval by the OECD.