No abstract

As the human population in the piedmont of South Carolina grows, the release of treated effluents from wastewater-treatment plants (WWTPs) will increasingly affect the chemical composition and biogeochemical processes of the region's rivers. We examined the impact of WWTP effluent on the solute chemistry of one such river, the Bush River, South Carolina, which experienced extremely low flow during the drought of 1998-2002. Two WWTPs discharge into the river and accounted for at least 70% of the river flow during the summer of 2002. The response of river solute concentrations to discharge from the downstream WWTP followed the expected dilution pattern. In contrast, the response to discharge from the upstream WWTP only followed the expected pattern for nonnutrient solutes (e.g., chloride and sodium). Concentrations of total dissolved nitrogen, nitrate, phosphate, and sulfate were all far below those expected from simple mixing calculations. At downstream sampling localities, however, conservative ions such as chloride and sodium had concentrations well below those predicted by mixing calculations. Instream biological processes associated with very low flow conditions, such as denitrification and sulfate reduction, may have caused the observed decrease in some nutrients. The cause of the discrepancy between the observed and predicted concentrations of conservative solutes remains unclear. Fluxes of solutes were much higher below the downstream WWTP. Our results indicate that the treated effluents of WWTPs have a significant impact on the biogeochemistry of piedmont rivers during drought periods. The impact is particularly large in rivers with small discharges. Extreme low flow conditions, however, may actually increase the

Naturally high total dissolved solids and upstream agricultural runoff often mask the influence of urban land cover on stream chemistry and biology. We examined the influence of headwater urbanization on the water chemistry, microbiology, and fish communities of the Big Brushy Creek watershed, a 96 km 2 drainage basin in the piedmont of South Carolina, USA. Concentrations of most major anions and cations (especially nitrate, sulfate, chloride, sodium, potassium, and calcium) were highest in the urban headwaters and decreased downstream. Generally, the highest concentrations of suspended coliform bacteria occurred in the urban headwaters. In contrast, stream habitat quality and the abundance, species richness, and species diversity of fishes did not differ significantly between urban and rural sites. Discharge of wastewater treatment plant effluent at one rural location caused an increase in concentrations of many solutes and possibly the abundance of benthic algae. We hypothesize that atmospheric dry deposition and domestic animal wastes are important sources of stream solutes and of coliform bacteria, respectively, in the urban headwaters. The lack of significant differences in fish abundance and diversity between urban and rural sites may indicate that urban development in the Big Brushy Creek watershed has not yet degraded habitat conditions greatly for stream fishes. Alternatively, agriculture or other land uses may have degraded stream habitat quality throughout the watershed prior to urbanization.

No abstract

Abstract. Stream nitrate (NO•-) concentrations were 2.6-7.0 times lower in watersheds in which red oak (Quercus rubra) stands were present than in other forested watersheds in northwestern Pennsylvania. Also, seasonal variations in NO•-concentrations were smaller in watersheds with oak stands than in watersheds without oak stands. Stream water concentrations of calcium, magnesium, potassium, sodium, chloride, and sulfate did not differ significantly between the two groups of watersheds. The variability in NO•-concentrations among streams did not appear to be due to differences in atmospheric nitrogen deposition among watersheds. Low stream NO•-concentrations occurred even if only 10-20% of a watershed was covered by oak stands. We suggest that oaks, rather than directly controlling NO•-losses, instead merely occur on soils which have low NO•-losses.

No abstract

Primary nonobstructive caliceal calculi were removed by nephrostolithotomy in 51 patients. Among the patients with caliceal stones indications for removal included pain in 36 (71 per cent), associated infection in 11 (21 per cent), progressive stone growth in 2 (4 per cent), hematuria in 1 (2 per cent) and flight status eligibility in 1 (2 per cent). Over-all, 300 patients have undergone percutaneous removal of upper urinary tract calculi, with a 97 per cent success rate. Successful removal was completed percutaneously in 49 patients (96 per cent). One patient remains asymptomatic with retained caliceal fragments and surgical stone removal was required in 1 additional patient. Complications occurred in 4 patients (8 per cent). One patient underwent transcatheter embolization of an intralobar artery to control renal bleeding. Three patients required placement of an internal Double-J ureteral stent to permit resolution of ureteral edema. Following recovery 34 of 36 patients (95 per cent) reported complete resolution of the preoperative pain for which the calculus was removed. Two patients had persistent urinary infection. The remaining patients reported no residual complaints. These observations suggest that pain and discomfort occasionally may be associated with nonobstructive caliceal calculi. Removal of caliceal calculi may permit resolution of associated discomfort in more than 90 per cent of all carefully selected patients.

A total of 12 patients underwent primary repair of ureteropelvic junction obstruction between November 1, 1985 and December 31, 1986. Ten patients underwent percutaneous incision of the ureteropelvic junction (endopyelotomy) as the initial effort to correct the obstruction. Two patients with ureteropelvic junction obstruction associated with an aberrant lower pole renal artery underwent dismembered pyeloplasty (Anderson-Hynes) via a flank incision. Of the 10 patients who underwent endopyelotomy 8 (80 per cent) have shown radiographic improvement. Radiographic stability of the obstructed ureteropelvic junction was demonstrated in the remaining 2 patients. No patient exhibited evidence of increased obstruction or decreased renal function. No patient required prolonged or rehospitalization for complications, and none required additional endoscopic or surgical procedures. All patients have remained clinically well after the initial release from the hospital.