Sediment toxicity testing of organic chemicals in the context of prospective risk assessment: A review
Diepens, N.J. ; Arts, G.H.P. ; Brock, T.C.M. ; Smidt, H. ; Brink, P.J. van den; Heuvel-Greve, M.J. van den; Koelmans, A.A. - \ 2014
Critical Reviews in Environmental Science and Technology 44 (2014)3. - ISSN 1064-3389 - p. 255 - 302.
species sensitivity distributions - amphipod corophium-volutator - midge chironomus-riparius - fresh-water sediments - polycyclic aromatic-hydrocarbon - field-collected sediment - aquatic food webs - quality guidelines - benthic invertebrates - whole-sediment
Sediment toxicity tests play an important role in prospective risk assessment for organic chemicals. This review describes sediment toxicity tests for microorganisms, macrophytes, benthic invertebrates and benthic communities. Current approaches in sediment toxicity testing are fragmentary and diverse. This hampers the translation of single species test results between freshwater, estuarine and marine ecosystems and to the population and community levels. A more representative selection of species and endpoints as well as a unification of dose metrics and exposure assessment methodologies across groups of test species, constitutes a first step towards a balanced strategy for sediment toxicity testing of single organic compounds in the context of prospective risk assessment.
Alternative states and population crashes in a resource-susceptible-infected model for planktonic parasites and hosts
Gerla, D.J. ; Gsell, A.S. ; Kooi, B.W. ; Ibelings, B.W. ; Donk, E. van; Mooij, W.M. - \ 2013
Freshwater Biology 58 (2013)3. - ISSN 0046-5070 - p. 538 - 551.
fresh-water phytoplankton - aquatic food webs - asterionella-formosa - viral-infection - dynamics - growth - diseases - diatoms - blooms - fungi
1. Despite the strong impact parasites can have, only few models of phytoplankton ecology or aquatic food webs have specifically included parasitism. 2. Here, we provide a susceptible-infected model for a diatom-chytrid hostparasite system that explicitly includes nutrients, infected and uninfected hosts, reproduction of the parasite on the hosts and free-living infective stages. 3. A distinguishing feature of the model is that parasite reproduction on host increases with nutrient availability to the infected host, as has been observed for many parasites and viruses. 4. It follows from this assumption that the parasite's basic reproduction number, R0, increases with nutrient concentration, because at higher nutrient concentrations, infected hosts consume more nutrients that are used for the reproduction of the parasite. 5. Another important result is that there may be two alternative states to which population densities can converge: one with only the host and one with host and parasite co-existing. In the latter, the parasite can invade a host population only if it is introduced above a threshold density. 6. Furthermore, the model shows a strong tendency for hostparasite cycles, which may be chaotic. Nutrient enrichment leads to increasing amplitude of these cycles, which may cause host or parasite population extinction caused by stochastic fluctuations during periods of low population density, which is the Paradox of Enrichment. 7. Finally, if alternative states and cycles co-occur, increased population cycle amplitude may drive the parasite below its threshold density for successful invasion, causing parasite extinction in a deterministic Paradox of Enrichment'. Published results confirm that hostparasite cycles and collapse of hostparasite systems may occur in real plankton communities. 8. Our results underline that ecological detail in hostparasite models may have consequences for disease dynamics that may be overlooked when ecological interactions between environment, host and parasite are not explicitly taken into account.
Uptake of sediment-bound bioavailable polychlorobiphenyls by benthivorous carp (Cyprinus carpio)
Moermond, C.T.A. ; Roozen, F.C.J.M. ; Zwolsman, J.J.G. ; Koelmans, A.A. - \ 2004
Environmental Science and Technology 38 (2004)17. - ISSN 0013-936X - p. 4503 - 4509.
sediment - biologische beschikbaarheid - polychloorbifenylen - benthos - karper - zoetwatervissen - meren - waterinvertebraten - chemicaliën - opname (uptake) - organische scheikunde - ecotoxicologie - waterbodems - sediment - bioavailability - polychlorinated biphenyls - benthos - carp - freshwater fishes - lakes - aquatic invertebrates - chemicals - uptake - organic chemistry - ecotoxicology - water bottoms - hydrophobic organic contaminants - aquatic food webs - contact time - pore-water - ingested sediment - extraction - lake - pollutants - fish
It is unclear whether accumulation of sediment-bound chemicals in benthivorous fish depends on the degree of sequestration in the sediment like it does for invertebrates. Here, we report on the potential of slow and fast desorbing sediment-bound polychlorobiphenyl (PCB) fractions for accumulation in carp (Cyprinus carpio) in lake enclosures treated with different nutrient doses
It is unclear whether accumulation of sediment-bound chemicals in benthivorous fish depends on the degree of sequestration in the sediment like it does for invertebrates. Here, we report on the potential of slow and fast desorbing sediment-bound polychlorobiphenyl (PCB) fractions for accumulation in carp (Cyprinus carpio) in lake enclosures treated with different nutrient doses. Routes of PCB uptake were quantitatively evaluated for 15 PCBs (log K-0W range 5.6-7.8) using model analysis. Fast-desorbing PCB fractions in the sediment were defined as the ratio of 6-h Tenax-extractable to (total) Soxhlet-extractable concentrations. These fractions varied between 4 and 22% and did not show a clear trend with log K-0W. However, bioaccumulation of PCBs in carp correlated much better with Tenax-extractable concentrations than with total-extractable concentrations. Nutrient additions in the enclosures had a positive effect on PCB accumulation. Model results show that PCB uptake in carp can be explained from (1) uptake through invertebrate food, (2) uptake from fast-desorbing fractions in ingested sediments, and (3) uptake from water, where PCBs are in partitioning equilibrium with fast-desorbing fractions. The main implication of this research is that fast-desorbing PCB fractions in sediments have great predictive potential for bioaccumulation in benthivorous fish.