Mark S. Schorr

Spatial and temporal analysis of pharmaceutical concentrations in the upper Tennessee River basin

The behavior of pharmaceutical compounds in aquatic ecosystems is not well defined. In order to determine spatial and temporal variations in concentrations of pharmaceuticals in the Tennessee River, water samples were collected from multiple points along the river and at the inflow of major tributaries. Sampling structure was designed to investigate trends between surface and subsurface samples, seasonal trends (winter, spring, summer, and fall), the direct influence of sewage treatment plants (upstream versus downstream), and the effect of downstream distance on pharmaceutical concentrations. All samples were quantified via solid phase extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). This method yielded reproducible quantitation at low parts per trillion (ng L(-1)) levels for all 14 analytes (acetaminophen, atorvastatin, caffeine, carbamazepine, ciprofloxacin, diltiazem, fluoxetine, levofloxacin, lovastatin, norfluoxetine, ranitidine, sertraline, sulfamethoxazole, and trimethoprim). Correlation analyses (depth, distance) and repeated-measures ANOVAs (season, sewage treatment plant proximity) were used to determine statistically significant trends for frequently detected pharmaceuticals (caffeine, carbamazepine, sulfamethoxazole). Caffeine and sulfamethoxazole were found to vary by season in subsurface samples; spring exhibited the highest concentrations. Carbamazepine varied in proximity to sewage treatment plant outfall with subsurface samples yielding greater concentrations downstream than upstream. In addition, individual pharmaceuticals displayed positive correlation between surface and subsurface samples and negative correlation with downstream distance from the headwaters.

Influence of Watershed Urbanization on Fine Sediment and Macroinvertebrate Assemblage Characteristics in Tennessee Ridge and Valley Streams

ABSTRACT Benthic macroinvertebrates and sediments were sampled in second- to fourth-order Tennessee Ridge and Valley streams and evaluated relative to urban land use and natural riparian cover. Site-specific estimates of EPT family richness (number of Ephemeroptera, Plecoptera, and Trichoptera families) ranged from 3 to 15. Urban land use in the watershed (from <1 to 27 %) was directly correlated with total suspended solids, sediment coverage, sediment depth, and oligochaete abundance. Watershed urban land use was inversely correlated with EPT family richness and relative abundances of EPT, filterers, and predators. Riparian forest cover was inversely correlated with total suspended solids, and total plant/wetland cover in the buffer was directly correlated with overall invertebrate taxa richness. Although natural riparian features appeared to have a positive influence on stream habitat quality and biotic conditions, correlations were stronger at the catchment scale. Relationships observed in this study underscore the negative effects of increased watershed urbanization on environmental conditions (more sedimentation) and benthic invertebrate assemblages (fewer pollution-sensitive insects, filterers, and predators) in small to midsize streams.

Description of a Floating Trap Net for Sampling Crappies

Abstract We developed a floating trap net suitable for sampling populations of crappies Pomoxis spp. This trap net consisted of two 8 × 8-ft front frames spaced 3 ft apart, followed by four 4 × 4-ft frames spaced 2.7 ft apart. All meshes were 0.5 in square. Each frame was fit with polyvinyl chloride floats. A 200 × 8-ft lead net was attached to center braces on the 8-ft frames. In trial net sets in Mississippi lakes (N = 98 net-nights) the net caught an average 54.4 crappies/net-night (range 0–134). Total lengths of crappies caught by the floating trap nets ranged from 1 to 16 in. Although the floating net is bigger than standard trap nets and more cumbersome to fish, we submit that the nets ability to yield large catches outweighs any inconveniences caused by its size.

Effects of Watershed Urban Land Use on Environmental Conditions and Fish Assemblages in Chattanooga Area Streams (Tennessee-Georgia)

ABSTRACT We studied fish assemblages within seven streams in the Ridge and Valley ecoregion near Chattanooga, Tennessee. These were all second- to fifth-order streams with small drainage areas (<23 km2). Sites were characterized in terms of water quality, habitat, and fish assemblages. Relationships among these features and land use were examined at both the riparian and watershed scales. Forty fish species representing nine families were collected by electrofishing. Site-specific findings included the vulnerable flame chub (Hemitremia flammae) and a disjunct population of southern redbelly dace (Phoxinus elythrogaster). Species richness and diversity varied considerably among sites, and index of biotic integrity (IBI) ratings ranged tiom very poor to faidgood. Species diversity and IBI scores were negatively correlated with watershed urban land use and positively correlated with rocky substrate. Urbanized watersheds were characterized by sites with higher levels of sedimentation and conductivity. Reaches draining well-forested watersheds exhibited more rocky substrate, higher levels of dissolved oxygen, lower temperatures, and more diverse fish assemblages. Riparian forest cover was positively correlated with rocky substrate but not correlated with species diversity or biotic integrity.

Localized Effects of Coal Mine Drainage on Fish Assemblages in a Cumberland Plateau Stream in Tennessee

ABSTRACT The upper watershed of North Chickamauga Creek (NCC), a fourth-order tributary to the Tennessee River, Tennessee, has been impacted by decades of acid mine drainage (AMD) from abandoned coal mines. We assessed fish assemblages, pH, conductivity, and sediment coverage at 12 study reaches (six AMD sites and six reference sites) in the Cumberland Plateau region of the NCC system, May-September 1998. Stream pH increased (3.6 to 6.0) and conductivity decreased (296 to 49 μS/cm) downstream of the AMD-impacted area; however, no discernable gradient was observed in sediment cover. Elevated conductivity at AMD-impacted sites reflected increased concentrations of dissolved metals and other inorganic ions. Reference sites exhibited higher pH (6.0–6.4) and lower conductivity (13–28 μS/cm). Acidified reaches were characterized by low fish species richness (r = 0.885, P = 0.0007) and abundance (r = 0.854, P = 0.0017); no fish were observed at sites where the mean pH was <5 Centrarchids (mostly bluegill [Lepomis macrochirus] and green sunfish [L. cyanellus]) comprised >90 % of the catch at AMD sites, whereas cyprinids (creek chub [Semotilus atromaculatus] and blacknose dace [Rhinichthys atratulus]) accounted for >90 % of the catch at reference sites. Findings from this study document the negative effects of acid drainage from coal mines on fish assemblages in a Cumberland Plateau stream.

Effects of stream acidification on lotic salamander assemblages in a coal-mined watershed in the Cumberland Plateau

We studied the effects of acid mine drainage (AMD) from abandoned coal mines on lotic salamanders and environmental conditions in the upper watershed (Cumberland Plateau) of North Chickamauga Creek (NCC; Tennessee River drainage) in southeastern Tennessee, USA, from 1996–97. Study sites (2nd- or 3rd-order reaches) were sampled in an AMD-influenced section (five sites) and in two reference streams (two minimally disturbed sites). A total of 212 plethodontids (premetamorphic larvae) representing four species were collected by kicknetting in riffles (n = 99) and electrofishing in mixed habitats (n = 113). The dusky salamander (Desmognathus fuscus) was the most abundant species in both AMD and reference reaches (> 80 – 90% of total catches), successively followed by the southern two-lined salamander (Eurycea cirrigera), spring salamander (Gyrinophilus porphyriticus), and red salamander (Pseudotriton ruber). Mining-influenced reaches were characterized by acidic flows (mean pH = 3.8–5.6), zero to low alkalinity, and elevated conductivity, sulfate, hardness, aluminum, and manganese, as well as very low abundances of salamanders. Reference reaches were slightly acidic to circumneutral (mean pH = 6.0–6.9) with low to moderate alkalinity, low levels of conductivity, hardness, sulfate, and metals, and high salamander abundances. Our findings document the impact of acid/metal pollution from past coal mining activities on lotic salamanders in a Cumberland Plateau stream.

Is ambient chitobiase activity a monitoring tool for impacts on secondary production in lotic systems

Chitobiase is one of two enzymes responsible for cleaving the chitin polymers that form arthropod exoskeletons and has been found to be predictive of secondary production for marine and freshwater zooplankton. Since chitobiase is re- leased into water during molting by aquatic arthropods, it is possible that ambient chitobiase activity may be a useful proxy of secondary production in aquatic systems. In the present study, surface water samples from the upper Tennessee River basin, USA, were collected and analyzed for chitobiase to determine how enzyme levels vary with season, water depth, and proximity to sewage treatment outfalls. Additionally, chitobiase activity was correlated with three pharmaceuti- cal compounds to assess if changes in chitobiase activity were associated with contaminants derived from sewage treat- ment plants. Chitobiase activity was significantly (p < 0.05) elevated in the fall relative to other seasons. Further, chitobiase activity displayed significant positive correlation (p < 0.05) between surface and subsurface samples and was negatively correlated (p < 0.05) with pharmaceutical concentrations in summer samples. These results indicate the potential for chitobiase as an assessment tool in estimating secondary production and as an ecotoxicological indictor.

Correlations of Watershed Housing Density with Environmental Conditions and Fish Assemblages in a Tennessee Ridge and Valley Stream

ABSTRACT We examined relationships of watershed housing density with instream environmental conditions and fish assemblage attributes in Mountain Creek, a third-order Ridge and Valley stream in Hamilton County, Tennessee (Chattanooga area). Habitat features and fish assemblages were sampled in May-June 2005 at seven sites (drainage areas <17 km2) in the middle-upper reaches of the Mountain Creek system (Tennessee River drainage). Watershed housing density upstream of the sites ranged from 49 housing units/km2 to 72 housing units/km2. Twenty-two fish species and 3,686 individuals were found at the seven sites. Native species richness per catchment area ranged from 1 species/km2 to 6 species/km2 at the individual sites. Index of biotic integrity (IBI) ratings varied from poor to fairlgood. Housing density was directly correlated with stream temperature, variation in discharge, fine sediment depth, and abundances of introduced and tolerant species; it was inversely correlated with dissolved oxygen, pH, variation in depth, substrate diversity, and native species richness. Although pockets in upper Mountain Creek appeared moderately healthy, most reaches exhibited signs of degradation. Catchments with > 60 housing units per km2 (four of seven sites) received IBI ratings of poor or poorlfair. Our results underscore the negative effects of residential development on water quality, hydrology, habitat complexity, and fish assemblages in a suburban stream.

Incidental Catch of Sport Fish in Cast Nets Used to Collect Baitfish in Lake Texoma, Oklahoma–Texas

Abstract Cast nets are a popular and effective means of collecting gizzard shad Dorosoma cepedianum and threadfin shad D. petenense for use as bait. To evaluate the incidental catch of sport fish in cast nets, three sizes of cast nets (2.4-, 3.0-, and 3.7-m diameter) were fished twice per month, January–December 1990, in shallow-water (<3 m deep) and deepwater areas at six cove sites on Lake Texoma, Oklahoma–Texas. Additionally, 2.4-m-diameter nets were fished near (<10 m) and away from (≥10 m) each of six boathouses on the lake, Shad collectively accounted for 91% of the total catch at cove sites and 87% at boathouse sites, whereas sport-fish species (mostly centrarchids) accounted for 5 and 11% of the total, respectively. The numbers of sport fish collected at cove sites did not vary significantly with the size of the net, but were greatest in shallow-water areas. The numbers of sport fish collected at boathouse sites were greatest in the summer and near artificial structures (e.g., boat slips, piers). ...