Silica gel as a particulate carrier of poorly water-soluble substances in aquatic toxicity testing

Breitholtz, Magnus; Ricklund, Niklas; Bengtsson, Bengt‐Erik; Persson, N. Johan

doi:10.1016/j.aquatox.2007.02.016

Cited by 19 publications

(7 citation statements)

References 36 publications

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“…However, published median effective concentration values for the crustacean Daphnia are in the range of 200 mg/L to 400 mg/L; these were obtained in 24 h acute toxicity to 8 d subchronic toxicity tests [40][41][42]. The copepod populations in the present study were close to extinction in 2 out of 3 experimental replicates exposed to 21 mg/L at the end of the experimental period, whereas development inhibition was observed at as low as 4 mg/L after a period that was sufficient for completing juvenile development [23,24]. Therefore, for test organisms with complex life cycles, like copepods, it is important to include different life stages in toxicity testing and design longterm tests ensuring stable exposure concentrations and allowing detection of stage-specific chronic effects.…”

Section: Effects Of Triclosan On Population Developmentmentioning

confidence: 55%

Passive dosing of triclosan in multigeneration tests with copepods – stable exposure concentrations and effects at the low μg/L range

Ribbenstedt

Mustajärvi

Breitholtz

et al. 2016

Enviro Toxic and Chemistry

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Ecotoxicity testing is a crucial component of chemical risk assessment. Still, due to methodological difficulties related to controlling exposure concentrations over time, data on long-term effects of organic chemicals at low concentrations are limited. The aim of the present study was, therefore, to test the applicability of passive dosing to maintain stable concentrations of the organochlorine bacteriocide triclosan in the water phase during a 6-wk multigeneration population development test with the harpacticoid copepod Nitocra spinipes. Triclosan was loaded into silicone (1000 mg), which was used as passive dosing phase in the exposure vials. The distribution ratio for triclosan between silicone and water (D silicone-water ) was 10466 AE 1927. A population development test was conducted at 3 concentration levels of triclosan that were measured to be 3 mg/L to 5 mg/L, 7 mg/L to 11 mg/L and 16 mg/L to 26 mg/L. The results demonstrate that passive dosing is applicable for long-term ecotoxicity testing of organic chemicals, including during significant growth of the test organism population. Shifts in the demographic structure of the population during exposure suggest the most severe effects were exerted on juvenile development. Progressively lower development index values in the populations exposed to increasing triclosan concentrations suggest developmental retardation. The results further stress the need for chronic exposure during ecotoxicity testing in chemical risk assessment because even the most sensitive endpoint was not significant until after 7 d of exposure.

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Section: Effects Of Triclosan On Population Developmentmentioning

confidence: 55%

Passive dosing of triclosan in multigeneration tests with copepods – stable exposure concentrations and effects at the low μg/L range

Ribbenstedt

Mustajärvi

Breitholtz

et al. 2016

Enviro Toxic and Chemistry

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“…Notably, the basic experimental design for this sediment bioassay is the same as for the two earlier published bioassays used for testing of water-soluble substances and organic extracts (see e.g. Breitholtz et al , 2007Karlsson et al 2008). This together with the fact that N. spinipes occurs naturally in both estuarine and marine environments makes the so-called LDR test relevant for assessment of a wide range of pollutants and environments.…”

Section: Discussionmentioning

confidence: 98%

“…Lang 1948;Wulff 1972;Abraham and Gopalan 1975) with the ability to utilize a variety of nutritionally poor diets (Weiss et al 1996) and has been used in ecotoxicological investigations for many years (e.g. Lindén et al 1979;Bengtsson and Bergström 1987;Magnusson et al 1996;Dave and Dennegård 1994;Breitholtz and Bengtsson 2001;Breitholtz et al , 2007Dahl et al 2006). The N. spinipes strain used in the present study was collected from the continuous stock culture at the Department of Applied Environmental Science (ITM, Stockholm University, Sweden), which originated from one female isolated from a Baltic Sea sediment sample collected in 1975 (Bengtsson 1978).…”

Section: Whole Sediment Test and Leachate Tests With N Spinipes-larvmentioning

confidence: 99%

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Biological and chemical characterization of harbour sediments from the Stockholm area

et al. 2009

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Purpose The main objective of the current study was to assess the impact of pleasure boat activities on harbour sediment quality in the Stockholm area. Sediment contamination is a growing ecological issue, and there is consequently a need to use sediment bioassays in combination with chemical analysis to determine the impact on the ecosystem. To generate sediment toxicity data relevant for the Baltic Sea, a secondary objective was to further develop and evaluate two well-established bioassays for saltwater, with the macroalga Ceramium tenuicorne and the crustacean Nitocra spinipes, to be useful also for toxicity testing of whole sediment. A major concern has been to minimize any manipulation of the sediments. A third objective was to assess whether a simple leaching procedure could be used to simulate sediment toxicity by comparing results from whole sediment and leachate tests. Materials and methods Surface sediments (0-2 cm) from five different types of pleasure boat harbours were collected. Chemical measurements of boat related compounds, i.e. tin organic substances (tributyltin (TBT), dibutyl tin, and monobutyl tin), polyaromatic hydrocarbons (PAHs), copper, zinc, lead, tin and irgarol were conducted. The sediments were tested for toxic effects using the established Microtox® test as well as the developed sediment tests with C. tenuicorne and N. spinipes. The endpoints are growth inhibition for the algal test and for the crustacean test mortality of larvae and rate of development expressed as the ratio between nauplia and copepodites. Two different procedures have been compared with both organisms, i.e. exposure to whole sediment and to leachate. The duration of both tests is around 1 week. Results and discussion All harbour locations were more or less heavily contaminated with remnants from use of antifouling paints. The sediment in a smaller marina (ca. 250 boats) contained the highest levels of TBT (max 1,400 µg/kg dry weight (dw)), whereas the centre of Stockholm City had the highest concentrations of all measured metals (max values Cu 252, Pb 830, Sn 25 and Zn 600 µg/kg dw) as well as high concentrations of total PAH (18 mg/kg dw). All three organisms were well suited to test the toxicity of contaminated sediments and were able to discriminate between more or less polluted sediments. The sediments in the smaller marina were most toxic along with sediments adjacent to slipways and sediments from the centre of Stockholm. No significant difference was found between the two different procedures for the algal tests. The whole sediment test was significantly more toxic to N. spinipes than the test using leachate. Conclusions Our results show that in spite of prohibition for many years to use tin organic substances and copper, boat activities still contribute with high concentrations of these toxic substances from anti-fouling paints in the surface sediment and that these have effects on organisms normally living in this environment. The present study has also demonstrated an expansion of two well-established t...

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“…To facilitate homogenous exposure of the organic sediment extracts and to increase the surface area to which the animals were exposed, the bottoms of each exposure beaker (20 ml) were covered with 100 mg silica gel (Merck, silica gel 60, Ø= 0.063-0.200 mm; Area: ∼500 m 2 /g; Breitholtz et al 2007). The spiking of the extracts was prepared the day before the start of the test to avoid residues from the solvents (Ulfsdotter Turesson et al 2007).…”

Section: N Spinipes-mortality and Larval Development Ratiomentioning

confidence: 99%

Hazard identification of contaminated sites—ranking potential toxicity of organic sediment extracts in crustacean and fish

et al. 2008

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Background, aim, and scope It is well known that contaminated sediments represent a potential long-term source of pollutants to the aquatic environment. To protect human and ecosystem health, it is becoming common to remediate contaminated sites. However, the great cost associated with, e.g., dredging in combination with the large numbers of contaminated sites makes it crucial to pinpoint those sites that are in greatest need of remediation. In most European countries, this prioritization process has almost exclusively been based on chemical analyses of known substances; only seldom toxicity data has been considered. The main objective of the current study was therefore to develop a tool for hazard identification of sediment by ranking potential toxicity of organic sediment extracts in a crustacean and a fish. A secondary objective was to investigate the difference in potential toxicity between compounds with different polarities. Materials and methods Early life stages of the crustacean Nitocra spinipes and the fish Oncorhynchus mykiss, which represent organisms from different trophic levels (primary and secondary consumer) and with different routes of exposure (i.e., ingestion through food, diffusive uptake, and maternal transfer), were exposed to hexane and acetone fractions (semi-polar compounds) of sediment from five locations, ranging from heavily to low contaminated. Preliminary tests showed that the extracts were non-bioavailable to the crustacean when exposed via water, and the extracts were therefore loaded on silica gel. Rainbow trout embryos were exposed using nano-injection technique.Results and discussion Clear concentration-response relationships of both mortality and larval development were observed in all tests with N. spinipes. Also for rainbow trout, the observed effects (e.g., abnormality, hemorrhage, asymmetric yolk sac) followed a dose-related pattern. Interestingly, our results indicate that some of the locations contained toxic semi-polar compounds, which are normally not considered in risk assessment of sediment since they are focused on compounds isolated in the hexane fraction. Conclusions The ranking of the five sediments followed the expected pattern of potential toxicity in both organisms, i.e., sediments with known pollution history caused major effects while reference sediments caused minor effects in the two test systems. Silica gel turned out to be an excellent carrier for exposure of N. spinipes to very hydrophobic and otherwise non-bioavailable sediment extracts. Recommendations and perspectivesSince both test systems demonstrated that a substantial part of the potential toxicity was caused by semi-polar compounds in the acetone fractions, this study enlightens our poor understanding of which compounds are causing adverse effects in environmental samples. Therefore, by investigating potential toxicity (i.e., hazard identification) as a first screening step in prioritizing processes, these implications could be avoided. For proper sediment risk assessment, we however recommend w...

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Silica gel as a particulate carrier of poorly water-soluble substances in aquatic toxicity testing

Cited by 19 publications

References 36 publications

Passive dosing of triclosan in multigeneration tests with copepods – stable exposure concentrations and effects at the low μg/L range

Passive dosing of triclosan in multigeneration tests with copepods – stable exposure concentrations and effects at the low μg/L range

Biological and chemical characterization of harbour sediments from the Stockholm area

Hazard identification of contaminated sites—ranking potential toxicity of organic sediment extracts in crustacean and fish

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