Sediment Toxicity in Mid-Continent Great Rivers (USA)

Abstract

As part of the Environmental Monitoring and Assessment Program for Great River Ecosystems (EMAP-GRE), sediment samples were collected from 447 randomly selected littoral sites along the main channels of the Ohio, Missouri, and Upper Mississippi Rivers between 2004 and 2006. Toxicity of these sediment samples was measured using a 7-day Hyalella azteca survival and growth test. Sixty-five sites (14.5%) exhibited lethal toxicity, and 130 sites (29.1%) exhibited decreased growth. In the EMAP-GRE probabilistic sampling design, each sampled site had a weight associated with it that determined the length (and proportion) of the river represented by that sample point in the population. Weighted whole-river estimates indicated that of the 4721 river km sampled, sediment from 15.9 ± 3.0% of the river (752 ± 50 km) were lethally toxic, 27.4 ± 3.5% (1289 ± 57 km) were toxic by way of growth inhibition, and 40.0 ± 3.7% (1887 ± 68 km) exhibited either lethal or growth toxicity. Selected toxic samples were analyzed for 21 pesticides, 20 polychlorinated biphenyl congeners, and 6 polybrominated diphenyl ether congeners. For all of the samples tested, the concentration levels of these analytes were mostly lower than known toxicity thresholds, and neither unionized ammonia concentration nor osmotic stress (as measured by conductivity) could account for the toxicity found in sediments. The spatial pattern of sediment toxicity cannot be readily explained by urbanization or agricultural land use at the subcatchment scale. We speculate that the distribution of toxic sediment is more likely due to a combination of localized sources, including polluted tributaries, and the redistribution of contaminated sediments from upriver. The sediment toxicity results from this study will be used, in combination with other sediment, biologic, and habitat metrics and indicators collected in the EMAP-GRE study, to help interpret and assess the condition of the Ohio, Upper Mississippi, and Missouri Rivers.

An Evaluation of the Relative Quality of Dike Pools for Benthic Macroinvertebrates in the Lower Missouri River, Usa

“…In that study, sediment samples from multiple near-shore habitats were combined, and therefore, local sediment conditions in dike pools could only be inferred by examining the upstream-downstream pattern in overall toxicity that they documented. Even though Echols et al (2008) suggested a low probability of adverse effects because of contaminants at our dike pool study sites, it is unknown why the conclusions regarding the risk of toxicity in sediments differ among studies (Canfield et al, 1998;Echols et al, 2008;Haring et al, 2011), but it is possible that differences in sampling methodologies and the relative sensitivities of toxicity endpoints may have led to these conflicting results.…”

“…Sediments collected from this tributary have concentrations of many contaminants and sediment‐quality parameters that are one to two orders of magnitude greater than those known in sediments of the Missouri River mainstem (Echols et al , ), and both previous and ongoing research have identified the Blue River as a significant contributor of contaminants, wastewater, nutrient enrichment and a myriad of urban pollutants from many sources (Stern and Stern, ; Wilkison et al , ). Haring et al () also reported a higher frequency of toxicity responses to invertebrates downstream of urban areas on the Lower Missouri River.…”

“…However, pools and associated backwaters of the Upper Mississippi River were formed by lock‐and‐dam management system different than that of the Lower Missouri River and are more lentic in their characteristics (Benke and Cushing, ). In contrast, a recent investigation of sediments in great river ecosystems reported system‐wide estimates of sediment toxicity in the Mississippi, Ohio and Missouri Rivers (Haring et al , ), and 43.2% of the sediment collection sites from the Missouri River mainstem caused a toxicity response for at least one endpoint. In that study, sediment samples from multiple near‐shore habitats were combined, and therefore, local sediment conditions in dike pools could only be inferred by examining the upstream–downstream pattern in overall toxicity that they documented.…”

“…Among large river studies that have documented effects of water or habitat quality limitations on aquatic invertebrates in off‐channel habitats, several factors responsible for these limitations have been identified, including flow conditions (Beckett and Pennington, ), presence of contaminants (Canfield et al , ), sediment toxicity (Haring et al , ), organic nutrient enrichment (Beckett and Pennington, ; Elstad, ), particle sizes of deposited sediments (Barnum and Bachmann, ; Schloesser et al , ) and turbidity (Berner, ). The ecological conditions in dike pool habitats may also change with highly variable local hydraulics and sediment transport related to dike geometry in relation to the main channel (Reuter et al , ; Jamieson et al , ).…”

“…Effects of anthropogenic disturbances on benthic macroinvertebrate communities in main channel habitats have been documented in the 1970s (Munger et al, 1974) and within the last decade (Poulton et al, 2003;. Elevated levels of hydrophobicorganic contaminants in the water column (Petty et al, 1995(Petty et al, , 1998 and in depositional sediments (Echols et al, 2008) have also been documented recently, and sediments collected downstream of urban areas are more frequently toxic to invertebrates such as Hyallela azteca in laboratory studies (Haring et al, 2011). The substantial shift in the relative contribution of habitats and substrate materials in the main channel resulting from physical modifications, taken together with stressors associated with degraded water quality, has likely altered the diversity and relative dominance within the aquatic macroinvertebrate community.…”