An attempt to assess the relevance of flood events—biomarker response of rainbow trout exposed to resuspended natural sediments in an annular flume

Abstract

There is a consensus within the scientific community that sediments act as a long-term sink for a variety of organic and inorganic pollutants, which, however, can re-enter the water column upon resuspension of deposited material under certain hydraulic conditions such as flood events. Within the implementation of the European Water Framework Directive, it is important to understand the potential short- and long-term impact of suspended particulate matter (SPM)-associated contaminants on aquatic organisms as well as the related uptake mechanisms for a sound risk assessment. To elucidate the effects of sediment-bound organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), rainbow trout (Oncorhynchus mykiss) were exposed to three resuspended natural sediments with different contamination levels. Physicochemical parameters including dissolved oxygen concentration, pH and temperature, total PAH concentration in sediments and SPM as well as different biomarkers of exposure in fish (7-ethoxyresorufin O-deethylase activity, biliary PAH metabolites, micronuclei, and lipid peroxidation) were measured following seven days of exposure within an annular flume, a device to assess erosion and deposition processes of cohesive sediment. Concentrations of PAHs in SPM remained constant and represented the different contamination levels in the un-suspended sediments. Significant differences in bile metabolite concentrations as well as in 7-ethoxyresorufin O-deethylase induction compared to control experiments (untreated animals and animals that were exposed in the annular flume without sediment) were observed for all exposure scenarios. The ratio between 1-hydroxypyrene in bile from fish exposed to the three different contamination levels was 1.0:3.6:10.7 and correlated well with (1) the ratio of pyrene concentrations in corresponding sediments which was 1.0:3.1:12.7 and (2) with the ratio of particle-bound pyrene in SPM which was 1.0:2.7:11.7. In contrast, hepatic lipid peroxidation and micronuclei formation represented the different contamination levels less conclusive. The results of this study clearly demonstrate that firmly bound PAH from aged sediments can become bioaccessible upon resuspension under flood-like conditions and are readily absorbed by aquatic organisms such as rainbow trout. Associated short-term effects were clearly documented and possible adverse long-term impacts due to genotoxicity are likely to follow.

Effect of recurrent sediment resuspension-deposition events on bioavailability of polycyclic aromatic hydrocarbons in aquatic environments

“…The particle sizes of original sediment used in this study were comparable to those collected from other rivers for sediment resuspension research (Alkhatib and Weigand, 2002;Feng et al, 2008). Furthermore, the SPS concentrations of this study were comparable to those obtained in sediment resuspension simulation experiments with other river sediments (Hudjetz et al, 2014;Wang et al, 2009) and the levels during a flood event in other rivers (Eyrolle et al, 2012). Although the resuspension strength (150 rpm, 6.4 N/m 2 ) was constant among the three resuspension events, the SPS concentrations followed the sequence of the first < the second < the third resuspension event for all sampling ports.…”

Towards science-based sediment quality standards—Effects of field-collected sediments in rainbow trout (Oncorhynchus mykiss)

“…This location was chosen because it is known to be only moderately contaminated with PCDD/Fs, PCBs and PAHs, and represents a wide range of fluvial systems with respect to the sediment particle size and organic carbon content (Feiler et al, 2013;Heininger et al, 2007). Sediment from this area had also been successfully used previously as a source material for experiments with spiked sediments and in simulated flood events Hudjetz et al, 2014). PR sediment was sampled in October 2013 from the river Elbe at a harbour entrance near Prossen, 13 km downstream from the Czech border (+50 • 55' 40" N, +14 • 6' 55" E).…”

Linking Ah receptor mediated effects of sediments and impacts on fish to key pollutants in the Yangtze Three Gorges Reservoir, China — A comprehensive perspective

“…A reasonable explanation for a lack of correlation despite present PAH metabolites could be that pyrene -the precursor to 1-OHPyr -is not regarded as an EROD inducer as described by Bols et al (1999) in RTL-W1 cells. In contrast, Hudjetz et al (2014) could show a similar but less pronounced gradient for EROD induction compared to 1-OHPyr increase in bile of rainbow trout exposed to sediment spiked Table 3 Parameters for PAH metabolites in bile of Pelteobagrus vachellii from sampling campaign May 2012. Parameters were concentrations of 1-hydroxypyrene (1-OHPyr) given as ng mL −1 , absorption of bile at 380 nm in dimensionless absorption units (A380) given as mL −1 , the concentration of 1-OHPyr normalized by A380 given as ng A380 −1 , and the ratio of 1-OHPyr to 1-hydroxyphenanthrene (1-OHPhe) in dimensionless units; Values are stated as means with standard deviation of pooled samples (n); n = 3, with exception of WU 2012 (n = 2).…”