A sediment quality triad consisting of (1) quantification of sediment polycyclic aromatic hydrocarbons (PAHs), total petroleum hydrocarbons (TPHs), and chloride concentrations; (2) a sediment bioassay using the amphipod Hyalella azteca; and (3) an in situ study of macroinvertebrate community structure were used to assess impacts of oil and/or brine spills on intermittent streams in southern Illinois. Thirty intermittent streams and three reference streams were selected for study based on oil and/or brine spill history since 1991. Sampling sites within study streams included one location above and three locations below the reported spill site. The sum of PAH concentrations exceeded the lower sediment quality guidelines (SQG) value for total PAHs (1.61 μg/g) in four of 130 sediment samples. All four samples exceeding the total PAH SQG were collected from locations within 40 m of where the spill entered the stream. However, there was no significant differences (p = 0.13) in mean sum of PAH concentrations among study and reference streams, and the reported volume of oil spilled into streams was not correlated with the sum of PAH concentrations measured in stream sediments. There was, however, a general trend toward greater PAH concentrations in sediment collected from streams where spills had occurred during the three years prior to sample collection ( × = 1.01 μg/g) compared to concentrations measured in sediment collected from streams where spills had occurred during nine to twelve years prior to sample collection ( × = 0.71 μg/g). No TPH concentrations were greater than the Canadian Ministry of Environment soil clean up standard of 1000 μg/g, and TPH concentrations were not significantly different between study and reference streams. Chloride concentrations in sediment from study streams were significantly greater than concentrations in sediment from reference streams (p < 0.028); however, chloride concentrations only exceeded the U.S. Environmental Protection Agency (U.S. EPA) recommended water quality criterion for chloride (230 mg/L) in two streams. Chloride concentrations in sediment were not significantly correlated with the reported volume of brine spilled into streams. The standardized sediment toxicity test component of the triad did suggest that sediment from several streams associated with oil and/or brine spills had adverse effects on H. azteca. However, there was no consistent indication of a corresponding association between the observed 3 effects and the contaminant concentrations measured in the sediment. Therefore, it was not possible to link the toxicity observed in H. azteca with the oil and/or brine spill. There were no measured differences in macroinvertebrate communities among sampling locations during the in situ macroinvertebrate community structure component of the sediment quality triad. There were no significant correlations between contaminant concentrations, water chemistry, or physical characteristics of the sediment and either taxa richness; Ephemeroptera, Plecoptera, and Trichoptera (EPT) richness; or family-level biotic index (FBI) scores. Habitat scores, biotic indexes, and water quality evaluations of studied intermittent streams suggest a degraded environment, and the correlation between habitat scores and invertebrate FBI suggested that habitat quality was the primary factor influencing invertebrate communities. Degraded habitat quality may in part be due to agricultural activities, the nature of intermittent streams, and/or the impacts of the oil industry. In the current study, it was not possible to separate the influences of oil and/or brine from other influences. Evaluations of some of the individual study streams did provide an indication that these streams had been exposed to oil and/or brine. However, there was little evidence to link oil and/or brine spills to effects observed in the streams studied.
|Name||ISTC Research Report Series|
- Polycyclic aromatic hydrocarbons -- Environmental aspects
- Petroleum hydrocarbons -- Environmental aspects
- Stream ecology -- Illinois
- Water -- Pollution -- Illinois
- Ecotoxicology -- Illinois