Development of a test method for Chironomus riparius using a formulated sediment

River water quality is strongly influenced by their sediments and their associated pollutants. To assess the toxic potential of sediments, sediment toxicity tests require reliable control sediments, potentially including formulated control sediments as one major option. Although some standardization has been carried out, one critical issue still remains the quality of sediment organic matter (SOM). Organic carbon not only binds hydrophobic contaminants, but may be a source of mild toxicity, even if the SOM is essentially uncontaminated. We tested two different sources of organic carbon and the mixture of both (Sphagnum peat (P) and one commercial humic substances preparation-HuminFeed(®), HF) in terms of life trait variables and expression profiles of selected life performance and stress genes of the nematode Caenorhabditis elegans. In synchronous cultures, gene expression profiling was done after 6 and 48 h, respectively. The uncontaminated Sphagnum P reduced growth, but increased numbers of offspring, whereas HF did not significantly alter life trait variables. The 6 h expression profile showed most of the studied stress genes repressed, except for slight to strong induction in cyp-35B1 (all exposures), gst-38 (only mixture), and small hsp-16 genes (all exposures). After 48 h, the expression of almost all studied genes increased, particularly genes coding for antioxidative defense, multiple xenobiotic resistance, vitellogenin-like proteins, and genes regulating lifespan. Overall, even essentially uncontaminated SOM may induce several modes of action on the molecular level in C. elegans which may lead to false results if testing synthetic xenobiotics. This contribution is a plea for a strict standardization of the SOM quality in formulated sediments and to check for corresponding effects in other model sediment organisms, especially if using molecular toxicity endpoints.

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“…As SOM, pure Sphagnum peat (P) (Naylor and Rodrigues 1995) and HuminFeed Ò (HF) were used. The compositions are given in Table 1.…”

Section: Sediment Formulationmentioning

confidence: 99%

Organic carbon source in formulated sediments influences life traits and gene expression of Caenorhabditis elegans

et al. 2011

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“…Therefore, the number of reported experiments with artificial sediments in the laboratory has been increasing (Naylor and Rodrigues, 1995;Clément and Cadier, 1998;Kemble et al, 1999;Ribeiro et al, 1999;Verrhiest et al, 2002;Feiler et al, 2004;Roman et al, 2007). These studies permit evaluating the effects of various types of pollutants on aquatic organisms under pre-established conditions.…”

Section: Artificial Sedimentsmentioning

confidence: 99%

Use of artificial sediment to assess toxicity of chromium on Chironomus xanthus, Danio rerio and Poecilia reticulata

et al. 2013

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AIM: Artificial sediments with simple formulations were used to assess the toxicity of Cr to C. xanthus, D. rerio and P. reticulata. METHODS: The organisms were exposed to two sediment formulations: one without organic matter (S0) and one with 1% organic matter (SIII), both contaminated with Cr at concentrations of 90, 180, 360, 720 and 1440 mg/kg for the assays with C. xanthus, and 375, 750, 1500 and 3000 mg/kg for those with the two fish species. Chromium was obtained from the potassium dichromate (K2Cr2O7). RESULTS: The results of the acute toxicity tests demonstrated a reduction of up to four times in toxicity with the presence of OM, consisting of biodegradable detritus, even at the low concentration used (1%), and that C. xanthus was most sensitive to the metal. The reduction in the chromium toxicity was indicated by the LC50 values, which were higher in SIII (1234.43 mg/kg; 2263.54 m/kg; 2244.48 mg/kg) than in S0 (340.56 mg/kg; 1731.04 mg/kg; 1733.55 mg/kg) for C. xanthus, D. rerio and P. reticulata, respectively. CONCLUSIONS: Because of the repeatability of the results obtained, the artificial sediments with simple formulations were satisfactory to assess toxicity and can thus provide reliable results in ecotoxicological studies

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“…Clément and Cadier (1998) observed similar results in their experiment as that incorporation of TetraMin ® into the (sediment) substrate enhanced growth and emergence of chironomids were observed. In addition, too much food could have significant impact on both water quality and partitioning of any chemical under test (Naylor and Rodrigues, 1995).…”

Section: Results and Discussion Effect Of Different Food On The Growtmentioning

confidence: 99%

Effect of Food and Light on the Sensitivity of Copper and Zinc to Freshwater Benthic Ostracod Heterocypris incongruens

Sevilla

Nakajima

Yamamoto

2013

J. of Wat. ^|^ Envir. Tech.

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Freshwater green algae Scenedesmus acutus and ostracod Heterocypris incongruens were used to evaluate sediment toxicity. They were exposed to a series of copper and zinc concentrations for 6 days. Effects of different food (algae and TetraMin ® ) and modifications of photoperiod in the toxicity test were also determined. TetraMin ® met the validity criteria, though it cannot be a complete substitute of algal food in the toxicity test. Modification of photoperiod has significant influenced on the ostracod toxicity test. The median lethal concentrations (LC50) of copper when fed with TetraMin ® were 270 µgCu/L and 571 µgCu/L under 24-h dark and light/dark conditions, respectively. Almost no significant effect on ostracod sensitivity to zinc when exposed under light (470 to 423 µgZn/L). On the other hand, light condition has similar effects on ostracod sensitivity to copper and zinc when fed with S. acutus. The preliminary results of the ostracod toxicity tests seem to show complex phenomena of multi exposure pathways and further investigation of the interrelationship between ostracod and food organisms is necessary.

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Development of a test method for Chironomus riparius using a formulated sediment

Cited by 45 publications

References 14 publications

Organic carbon source in formulated sediments influences life traits and gene expression of Caenorhabditis elegans

Organic carbon source in formulated sediments influences life traits and gene expression of Caenorhabditis elegans

Use of artificial sediment to assess toxicity of chromium on Chironomus xanthus, Danio rerio and Poecilia reticulata

Effect of Food and Light on the Sensitivity of Copper and Zinc to Freshwater Benthic Ostracod Heterocypris incongruens

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