Paraffin and other petroleum waxes in the southern North Sea.

Petroleum waxes (PWs) are recognized as ubiquitously emerging marine pollutants. However, knowledge on their occurrence, particularly as persistent floaters of small size (<5 mm) in marine surface water, is scarce. For this study, 24 samples were collected in the North Sea by net-sampling (100 µm-mesh). Particles of wax-like appearance were detected at 14 stations. Similar appearing PWs from six stations with highest abundances were pooled per station and analyzed by ATR-FTIR (Attenuated total reflectance Fourier-transform infrared spectroscopy) and gas chromatography. Samples contained paraffin particles, being partly accompanied by substances like fatty acids and fatty alcohols. Using both analytical techniques provided a reliable detection of PWs and more details on their chemical composition. Furthermore, exemplarily the presence of PWs of 20-500 µm size was proven by µFTIR imaging. This study gives valuable insights into PW pollution in the North Sea, emphasizing the need for harmonized detection methods, ideally accompanying microplastics monitoring.

The potential for dispersant use as a maritime oil spill response measure in German waters.

In case of an oil spill, dispersant application represents a response option, which enhances the natural dispersion of oil and thus reduces coating of seabirds and coastal areas. However, as oil is transferred to the water phase, a trade-off of potential harmful effects shifted to other compartments must be performed. This paper summarizes the results of a workshop on the current knowledge on risks and benefits of the use of dispersants with respect to specific conditions encountered at the German sea areas. The German North Sea coast is a sensitive ecosystem characterised by tidal flats, barrier islands and salt marshes. Many prerequisites for a potential integration of dispersants as spill response option are available in Germany, including sensitivity maps and tools for drift modelling of dispersed and undispersed oil. However, open scientific questions remain concerning the persistence of dispersed oil trapped in the sediments and potential health effects.

Passive Sampling in Regulatory Chemical Monitoring of Nonpolar Organic Compounds in the Aquatic Environment.

We reviewed compliance monitoring requirements in the European Union, the United States, and the Oslo-Paris Convention for the protection of the marine environment of the North-East Atlantic, and evaluated if these are met by passive sampling methods for nonpolar compounds. The strengths and shortcomings of passive sampling are assessed for water, sediments, and biota. Passive water sampling is a suitable technique for measuring concentrations of freely dissolved compounds. This method yields results that are incompatible with the EU's quality standard definition in terms of total concentrations in water, but this definition has little scientific basis. Insufficient quality control is a present weakness of passive sampling in water. Laboratory performance studies and the development of standardized methods are needed to improve data quality and to encourage the use of passive sampling by commercial laboratories and monitoring agencies. Successful prediction of bioaccumulation based on passive sampling is well documented for organisms at the lower trophic levels, but requires more research for higher levels. Despite the existence of several knowledge gaps, passive sampling presently is the best available technology for chemical monitoring of nonpolar organic compounds. Key issues to be addressed by scientists and environmental managers are outlined.

Accelerated solvent extraction (ASE) for purification and extraction of silicone passive samplers used for the monitoring of organic pollutants.

Silicone passive samplers have gained an increasing attention as single-phased, practical and robust samplers for monitoring of organic contaminants in the aquatic environment in recent years. However, analytical challenges arise in routine application during the extraction of analytes as silicone oligomers are co-extracted and interfere severely during chemical analyses (e.g. gas chromatographic techniques). In this study, we present a fast, practical pre-cleaning method for silicone passive samplers applying accelerated solvent extraction (ASE) for the removal of silicone oligomers prior to the water deployment (hexane/dichloromethane, 100 °C, 70 min). ASE was also shown to be a very fast (10 min) and efficient extraction method for non-polar contaminants (non-exposed PRC recoveries 66-101 %) sampled by the silicone membrane. For both applications, temperature, extraction time and the solvent used for ASE have been optimized. Purification of the ASE extract was carried out by silica gel and high-pressure liquid size exclusion chromatography (HPLC-SEC). The silicone oligomer content was checked by total reflection X-ray fluorescence spectroscopy (TXRF) in order to confirm the absence of the silicone oligomers prior to analysis of passive sampler extracts. The established method was applied on real silicone samplers from the North- and Baltic Sea and showed no matrix effects during analysis of organic pollutants. Internal laboratory standard recoveries were in the same range for laboratory, transport and exposed samplers (85-126 %).

Relational information processing of novel unrelated actions by infants.

Declarative memory in infants is often assessed via deferred imitation. Not much is known about the information processing basis of the memory effect found in these experiments. While in the typical deferred imitation study the order of actions remains the same during demonstration and retrieval, in two experiments with n=30 respective n=25, 10- and 11-month-old infants, the order of novel unrelated actions in demonstration and retrieval was varied (same, reversed, mixed). This allowed a separation of item-specific from item-relational information processing. In both experiments best memory performance was found when the order of target actions remained the same during encoding and recall, demonstrating that infants seem to rely on item-specific as well as item-relational information which has to be ad hoc constructed while encoding.

Long-term effects of the Aznalcóllar mine spill-heavy metal content and mobility in soils and sediments of the Guadiamar river valley (SW Spain).

In 1998, a toxic spill from a pyrite mine (Aznalcóllar, SW Spain) contaminated some 40 km2 of the Agrio and Guadiamar river valley with heavy metal-enriched tailings sludge and acidic mine water. The aim of this study is to describe the long-term effects of heavy metal migration particularly with respect to the extent of vertical redistribution of As, Cd, Cu, Fe, Pb, S, Sb and Zn in soils and sediments of the river Guadiamar 4 years after the accident. For an assessment of the mobility behaviour, chemical associations of Cu, Pb, Sb and Zn in depth profiles polluted by tailings were determined by using sequential extraction procedures. In 2002, residues of toxic tailings were found in several places along the river Guadiamar. Heavy weathering has accelerated heavy metal displacement and contamination of the surrounding soil. Two element groups of contrary mobility can be distinguished: Cd and Zn are highly mobile and show strong displacements in acidic surroundings. Accumulation zones for Cd and Zn develop in less acidic soil layers due to the occurrence of Fe oxides, which constitute retaining fractions for these elements. The immobile elements Pb and Sb represent the second group. Highest concentrations of Pb and Sb are found in the tailings sludge. Cu and As show a variable distribution pattern. As a consequence of the heavy metal migration, an accumulation zone has formed up to 30 cm into the underlying soil at the time of investigation. In the future, there may be further penetration of heavy metals to greater depths.