Peter van den Hurk

Abstract To evaluate the process of trophic transfer of microplastics, it is important to consider various abiotic and biotic factors involved in their ingestion, egestion, bioaccumulation, and biomagnification. Toward this end, a review of the literature on microplastics has been conducted to identify factors influencing their uptake and absorption; their residence times in organisms and bioaccumulation; the physical effects of their aggregation in gastrointestinal tracts; and their potential to act as vectors for the transfer of other contaminants. Limited field evidence from higher trophic level organisms in a variety of habitats suggests that trophic transfer of microplastics may be a common phenomenon and occurs concurrently with direct ingestion. Critical research needs include standardizing methods of field characterization of microplastics, quantifying uptake and depuration rates in organisms at different trophic levels, quantifying the influence that microplastics have on the uptake and/or depuration of environmental contaminants among different trophic levels, and investigating the potential for biomagnification of microplastic-associated chemicals. More integrated approaches involving computational modeling are required to fully assess trophic transfer of microplastics. Integr Environ Assess Manag 2017;13:505–509. © 2017 SETAC Key Points The trophic transfer of microplastics are dependent on a variety of abiotic and biotic factors including the feeding strategies of the organisms within the food web, their exposure to these particles in their habitat, the physical and chemical characteristics of the particles, and their residence times within organisms. Limited field evidence from higher trophic level organisms in a variety of habitats suggests that trophic transfer of microplastics may be occurring concurrently with direct ingestion. Integrated approaches involving computational modeling will be required to fully assess trophic transfer of microplastics.

A PCR assay was developed for the diagnosis of invasive aspergillosis in immunocompromised patients. For this purpose, the complete nucleotide sequences of the genes encoding the 18S rRNA of Aspergillus nidulans, Aspergillus terreus, Aspergillus niger, and Aspergillus flavus were elucidated and aligned to the sequences of Aspergillus fumigatus and other clinically relevant prokaryotic and eukaryotic microorganisms. Genus-specific sequences could be identified in the V7 to V9 region of 18S rRNA. By using hot-start PCR, Southern blot hybridization, and restriction enzyme analysis, Aspergillus-specific and -sensitive determination was achieved. Five of six immunosuppressed mice experimentally infected with A. fumigatus developed infection, and rRNA could be detected in each case, even in livers with the absence of positive cultures. Aspergillus species were detected by PCR in four neutropenic patients with proven aspergillosis, although Aspergillus species had been isolated from only one bronchoalveolar lavage (BAL) fluid sample. Aspergillus species were detected by PCR in two more patients suspected of having infection. Positive PCR signals were obtained from the BAL samples of 3 of 8 neutropenic patients who had developed pulmonary infiltrates, but none were obtained from the samples of 14 nonimmunosuppressed patients. These results indicate the potential value of PCR to detect Aspergillus species in BAL samples and, therefore, to identify neutropenic patients at risk for invasive aspergillosis.

Toxicity testing of whole sediments was conducted as part of the Bremerhaven Workshop designed to test various methods (chemical and biological) for assessing the status of North Sea waters, sediments and biota.Six investigators from 4 countries were involved; laboratory testing was conducted after transporting field-collected sediments distances varying from tens of miles to thousands of miles.Sediments were tested from 2 contamination gradients, one from an abandoned drilling site, and the other from the mouth of the Elbe northwest across the German Bight.Methods included 11 different tests (20 end-points), 3 species of amphipod, a polychaete, a clam, an oyster and a bacterium.Amphipod 10 d acute lethality tests and a 48 h oyster larvae abnormal development test most clearly determined gradients in toxicity that corresponded with chemical and in situ con~munity data.Lack of response was observed in Microtox and clam reburial tests.A polychaete growth test conducted in North America provided useful but not convincing information.A 24 h oyster larvae survival test conducted separately in England and The Netherlands gave results that were counter to the other tests and difficult to interpret.Survival and metamorphosis tests with older oyster larvae did not show consistent, interpretable gradients for the drilling site but did for the German Bight.The responsiveness of some tests may have been affected by a maximum 3 wk sediment holding time prior to testing; other tests did not provide usable information relative to either the burden of evidence of all tests, or corresponding chemical contamination data and benthic infaunal community structure.Based on the results of this workshop, currently the most useful sediment toxicity tests for general assessment and regulatory use in Europe are infaunal amphipod survival and 48 h oyster larval development tests.