Monitoring van paraffine-achtige stoffen op Nederlandse stranden en in magen van Noordse Stormvogels

Within the KB-Program System Earth Management 2018 (KB-24-002-036) a pilot study was conducted into options to monitor of paraffin- or palmfat-like substances on Dutch beaches and in stomachs of corpses of beached Northern Fulmars. Such substances are, in part legally, discharged by tanker ships cleaning their tanks at sea.Paraffin was chemically identified by the presence of alkanes in the samples. It remains to be investigated in detail which other mineral oil derivatives may show similar alkane patterns. In the absence of alkanes further analyses were conducted to assess the type of material involved.Samples taken from beaches showed to be paraffin in 30 of 32 analyses (94%). One sample contained palmoil related substances, one sample remained unclear but contained phthalates (eg used as plastic softeners). The materials from bird stomachs proved to be different. Paraffin was only found in 31% of 32 samples. In 41% of the stomachs vegetable fatty substances were demonstrated, usually palm oil related. The remainder of samples had an uncertain mix of vegetable and animal fats. The difference between beaches and bird stomachs may have several backgrounds, including attraction for wildlife, melting points, and biodegradability.Over 20% of fulmars found in the Netherlands has chemical suspect materials in the stomach. Not much is known about potential health impacts. Over the years no clear changes can be detected. Quantities of material ingested are highly variable. Frequency of occurrence may slightly reduce over the more recent years, but there is no statistically significant trend. It would make sense to add records on chemical suspect materials in fulmar stomachs to the existing monitoring of plastics in the framework of OSPAR and the EU Marine Strategy Framework Directive. Clearly chemical analyses of substances encountered on beaches and in birds is additionally recommended

Improving the knowledge basis for advice on North Sea horse mackerel : developing new methods to get insight on stock boundaries and abundance

The North Sea horse mackerel stock is currently classified by ICES as a data poor stock, for which the catch advice is based on the trend in an abundance index. The development of an analytical stock assessment, necessary to give more accurate advice, is hampered by a number of limitations on the input data, among which the most important are the poor quality of catch-at-age data and the absence of a targeted survey for North Sea horse mackerel. The aim of this project was to study possibilities to improve the data quality used for an analytical stock assessment model

Toxic elements and speciation in seafood samples from different contaminated sites in Europe

The presence of cadmium (Cd), lead (Pb), mercury (THg), methylmercury (MeHg), arsenic (TAs), inorganic arsenic (iAs), cobalt (Co), copper (Cu), zinc (Zn), nickel (Ni), chromium (Cr) and iron (Fe) was investigated in seafood collected from European marine ecosystems subjected to strong anthropogenic pressure, i.e. hotspot areas. Different species (Mytilus galloprovincialis, n=50; Chamelea gallina, n=50; Liza aurata, n=25; Platichthys flesus, n=25; Laminaria digitata, n=15; and Saccharina latissima, n=15) sampled in Tagus estuary, Po delta, Ebro delta, western Scheldt, and in the vicinities of a fish farm area (Solund, Norway), between September and December 2013, were selected to assess metal contamination and potential risks to seafood consumers, as well as to determine the suitability of ecologically distinct organisms as bioindicators in environmental monitoring studies. Species exhibited different elemental profiles, likely as a result of their ecological strategies, metabolism and levels in the environment (i.e. seawater and sediments). Higher levels of Cd (0.15–0.94 mg kg-1), Pb (0.37-0.89 mg kg-1), Co (0.48–1.1 mg kg-1), Cu (4.8–8.4 mg kg-1), Zn (75–153 mg kg-1), Cr (1.0–4.5 mg kg-1) and Fe (283–930 mg kg-1) were detected in bivalve species, particularly in M. galloprovincialis from Ebro and Po deltas, whereas the highest content of Hg was found in P. flesus (0.86 mg kg-1). In fish species, most Hg was organic (MeHg; from 69 to 79%), whereas lower proportions of MeHg were encountered in bivalve species (between 20 and 43%). The highest levels of As were found in macroalgae species L. digitata and S. latissima (41 mg kg-1 and 43 mg kg-1, respectively), with iAs accounting almost 50% of the total As content in L. digitata but not with S. latissima nor in the remaining seafood samples. This work highlights that the selection of the most appropriate bioindicator species is a fundamental step in environmental monitoring of each contaminant, especially in coastal areas. Furthermore, data clearly shows that the current risk assessment and legislation solely based on total As or Hg data is limiting, as elemental speciation greatly varies according to seafood species, thus playing a key role in human exposure assessment via food