Interspecific and Spatial Comparisons of Perfluorinated Compounds in Bighead and Silver Carp in the Illinois River, Illinois, USA.

We examined perfluoroalkyl compounds (PFC) in bighead (BHCP; Hypophthalmichthys nobilis) and silver (SVCP; H. molitrix) carp from the Illinois River, Illinois, USA. Summed PFC concentrations in whole fish did not differ by species or river reach. Perfluorooctanesulfonate (PFOS) concentrations were much greater in whole fish (16.4 ng/g) than in fillets (3.4 ng/g). PFOS concentrations represented 35%-51% of total measured PFC concentrations in whole fish, and in fillets were weakly associated with carcass mass (R2=0.17, p=0.01) and % carcass lipid (R2=0.16, p=0.01). No such relationship was observed in whole fish. The relationship between concentrations of individual PFC congeners in whole fish and carcass mass or % lipid content varied by species. Our study demonstrated that filter-feeders such as BHCP and SVCP can accumulate measureable concentrations of PFC and these results are important for understanding the fate of these compounds in large river systems.

Short-term effects of military fog oil on the fountain darter (Etheostoma fonticola).

Toxicity tests evaluated chronic and sublethal effects of fog oil (FO) on a freshwater endangered fish. FO is released during military training as an obscurant smoke that can drift into aquatic habitats. Fountain darters, Etheostoma fonticola, of four distinct life stages were exposed under laboratory conditions to three forms of FO. FO was vaporized into smoke and allowed to settle onto water, violently agitated with water, and dosed onto water followed by photo-oxidization by ultraviolet irradiation. Single smoke exposures of spawning adult fish did not affect egg production, egg viability, or adult fish survival in 21-day tests. Multiple daily smoke exposures induced mortality after 5 days for larvae fish. Larvae and juvenile fish were more sensitive than eggs in 96-h lethal concentration (LC50) tests with FO­water mixtures and photo-oxidized FO. Water-soluble FO components photo-modified by ultraviolet radiation were the most toxic, thus indicating the value of examining weathering and aging of chemicals for the best determination of environmental impact.

Acute toxicity of nitrate and nitrite to sensitive freshwater insects, mollusks, and a crustacean.

Both point- and nonpoint-sources of pollution have contributed to increased inorganic nitrogen concentrations in freshwater ecosystems. Although numerous studies have investigated the toxic effects of ammonia on freshwater species, relatively little work has been performed to characterize the acute toxicity of the other two common inorganic nitrogen species: nitrate and nitrite. In particular, to our knowledge, no published data exist on the toxicity of nitrate and nitrite to North American freshwater bivalves (Mollusca) or stoneflies (Insecta, Plecoptera). We conducted acute (96-h) nitrate and nitrite toxicity tests with two stonefly species (Allocapnia vivipara and Amphinemura delosa), an amphipod (Hyalella azteca), two freshwater unionid mussels (Lampsilis siliquoidea and Megalonaias nervosa), a fingernail clam (Sphaerium simile), and a pond snail (Lymnaea stagnalis). Overall, we did not observe a particularly wide degree of variation in sensitivity to nitrate, with median lethal concentrations ranging from 357 to 937 mg NO(3)-N/l; furthermore, no particular taxonomic group appeared to be more sensitive to nitrate than any other. In our nitrite tests, the two stoneflies tested were by far the most sensitive, and the three mollusks tested were the least sensitive. In contrast to what was observed in the nitrate tests, variation among species in sensitivity to nitrite spanned two orders of magnitude. Examination of the updated nitrite database, including previously published data, clearly showed that insects tended to be more sensitive than crustaceans, which were in turn more sensitive than mollusks. Although the toxic mechanism of nitrite is generally thought to be the conversion of oxygen-carrying pigments into forms that cannot carry oxygen, our observed trend in sensitivity of broad taxonomic groups, along with information on respiratory pigments in those groups, suggests that some other yet unknown mechanism may be even more important.

Contaminant concentrations in Asian carps, invasive species in the Mississippi and Illinois Rivers.

Populations of invasive fishes quickly reach extremely high biomass. Before control methods can be applied, however, an understanding of the contaminant loads of these invaders carry is needed. We investigated differences in concentrations of selected elements in two invasive carp species as a function of sampling site, fish species, length and trophic differences using stable isotopes (delta (15)N, delta (13)C). Fish were collected from three different sites, the Illinois River near Havana, Illinois, and two sites in the Mississippi River, upstream and downstream of the Illinois River confluence. Five bighead carp (Hypophthalmichthys nobilis) and five silver carp (Hypophthalmichthys molitrix) from each site were collected for muscle tissue analyses. Freshwater mussels (Amblema plicata) previously collected in the same areas were used as an isotopic baseline to standardize fish results among sites. Total fish length, trophic position, and corrected (13)C, were significantly related to concentrations of metals in muscle. Fish length explained the most variation in metal concentrations, with most of that variation related to mercury levels. This result was not unexpected because larger fish are older, giving them a higher probability of exposure and accumulation of contaminants. There was a significant difference in stable isotope profiles between the two species. Bighead carp occupied a higher trophic position and had higher levels of corrected (13)C than silver carp. Additionally bighead carp had significantly lower concentrations of arsenic and selenium than silver carp. Stable isotope ratios of nitrogen in Asian carp were at levels that are more commonly associated with higher-level predators, or from organisms in areas containing high loads of wastewater effluent.

Effects of freshly neutralized aluminum on oxygen consumption by freshwater invertebrates.

The hypothesis tested in this study was if a pulse of precipitating aluminum (Al) at circumneutral pH covers the body of an invertebrate and, therefore, reduces the surface area available for respiration, organisms exposed to precipitating Al in an experimental system should consume less oxygen than organisms not exposed to aluminum. To test this hypothesis, experiments were conducted in the laboratory placing test organisms in biochemical oxygen demand (BOD) bottles containing a recently neutralized acidic, Al-enriched solution; conditions were meant to loosely mimic those of an acidic, Al-rich stream flowing into a larger, neutralizing receiving stream. The experiments suggested that freshly neutralized Al, i.e., Al in transition from ionic species in acidic waters to polymers or precipitating hydroxides after a rapid increase to pH > or = 6.8, impaired oxygen consumption by D. magna in a repeatable, dose-dependent fashion. Precipitating Al also impaired oxygen consumption by the perlid stoneflies Perlesta lagoi and Acroneuria abnormis, at the lower concentrations used, but higher concentrations resulted in oxygen consumption similar to that of controls. An ionoregulatory impairment response may explain this trend. Aluminum did not affect oxygen consumption by the larger, detritivorous stonefly, Pteronarcys pictetii.

Impaired Acroneuria sp. (Plecoptera, Perlidae) populations associated with aluminum contamination in neutral pH surface waters.

Our aim was to quantify impairment to invertebrate predator populations, particularly to Acroneuria sp. (Plecoptera, Perlidae), downstream of an acid mine drainage-impacted tributary to the North Fork of the Powell River, southwestern Virginia. Predatory insects comprised 9.0 +/- 1.3% of the total abundance at the three stations upstream of the impacted tributary, but were significantly reduced (p = 0.0039) downstream (3.9 +/- 0.6%). Acroneuria sp. populations followed the same trend, with the upstream average (2.3 and 2.8%) being significantly higher (p < 0.05) than the downstream averages (0.2 and 0%) during 1999 and 2000, respectively. Using correlation analysis, we evaluated the relationship between the percent abundance of Acroneuria sp. throughout this reach and metal concentrations in water, sediment, and biological tissues (invertebrate predators and primary consumers). Water column aluminum (Al) concentration was the only parameter that was significantly correlated with percent Acroneuria sp. abundance, with correlation coefficients of -0.845 and -0.873 during 1999 and 2000, respectively. While this correlation exists, it may not indicate a causal relationship, and experiments should be conducted to determine the long-term toxicity of various Al species to perlid stoneflies.

An integrative assessment of a watershed impacted by abandoned mined land discharges.

The Ely Creek watershed in Lee County, VA, USA, contains an abundance of abandoned mined land areas with acid mine drainage (AMD) that contaminate the majority of the creek and its confluence into Stone Creek. Acidic pH measurements ranged from 2.73 to 5.2 at several stations throughout the watershed. Sediments had high concentrations of iron (approximately 10,000 mg kg-1), aluminum (approximately 1,500 mg kg-1), magnesium (approximately 400 mg kg-1) and manganese (approximately 150 mg kg-1), and habitat was partially to non-supporting at half of the stations due to sedimentation. Benthic macroinvertebrate surveys at six of 20 stations sampled in the watershed yielded no macroinvertebrates, while eight others had total abundances of only one to nine organisms. Four reference stations contained > or = 100 organisms and at least 13 different taxa. Asian clam in situ toxicity testing supported field survey results. Laboratory, 10-day survival/impairment sediments tests with Daphnia magna and Chironomus tentans and 48-h water column bioassays with Ceriodaphnia dubia indicated environmental stress to a lesser degree. Ten parameters that were directly influenced by AMD through physical, chemical, ecological and toxicological endpoints were assimilated into an ecotoxicological rating (ETR) to form a score of 0-100 points for the 20 sampling stations, and the lower the score the greater the AMD stress. Twelve of the 15 sampling stations influenced by AMD received an ETR score of 13.75-57.5, which were categorized as severely stressed (i.e. comprised the < 60 percentile category) and worthy of the highest priority for future ecological restoration activities in the watershed.

Relative acute toxicity of acid mine drainage water column and sediments to Daphnia magna in the Puckett's Creek Watershed, Virginia, USA.

Acid mine drainage (AMD) is produced when pyrite (FeS(2)) is oxidized on exposure to oxygen and water to form ferric hydroxides and sulfuric acid. If produced in sufficient quantity, iron precipitate, heavy metals (depending on soil mineralogy), and sulfuric acid may contaminate surface and ground water. A previous study of an AMD impacted watershed (Puckett's Creek, Powell River drainage, southwestern Virginia, USA) conducted by these researchers indicated that both water column and sediment toxicity were significantly correlated with benthic macroinvertebrate community impacts. Sites that had toxic water or sediment samples had significantly reduced macroinvertebrate taxon richness. The present study was designed to investigate the relative acute toxicity of acid mine drainage (AMD) water column and sediments to a single test organism (Daphnia magna) and to determine which abiotic factors were the best indicators of toxicity in this system. Nine sampling stations were selected based on proximity to major AMD inputs in the watershed. In 48-h exposures, sediment samples from three stations were acutely toxic to D. magna, causing 64-100% mortality, whereas water samples from five stations caused 100% mortality of test organisms. Forty-eight-hour LC50 values ranged from 35 to 63% for sediment samples and 27 to 69% for water column samples. Sediment iron concentration and several water chemistry parameters were the best predictors of sediment toxicity, and water column pH was the best predictor of water toxicity. Based on these correlations and on the fact that toxic sediments had high percent water content, water chemistry appears to be a more important adverse influence in this system than sediment chemistry.