Periphytic communities were investigated using glass slide substrates at four sites downstream from the montane Hyalite Reservoir, Montana, USA. Comparison of the most upstream site with the three lower sites revealed that the discharges to Hyalite Creek stimulated periphytic productivity, increased periphytic proportions of chlorophyll ° in the organic accumulations, and increased diatom species diversity and evenness. As nitrogen concentration was the only stream physiochemical parameter which correlated with periphytic variations, it is probable that ammonia nitrogen discharged from the reservoir was the primary factor influencing periphytic growth. Cocconeis placentula var. lineata dominated generally °70—80% of the diatom communities at the three downstream sites whereas only three individuals of this species were observed at the upper site. Data from two successional series following colonization of the slides suggested that species other than Cocconies had higher initial growth rates. It appears the Cocconies become dominant at the three downstream sites because of higher efficiencies for obtaining or incorporating limiting nitrogen resources: species other than Cocconeis dominated the diatom communities in which nitrogen concentrations were enriched,apparently because of higher potential growth rates which could be realized with the elevated nutrient conditions. A brief review of the literature and new data presented indicate that species diversity first increases and then decreases as a function of resource abundance.

We report our long-term experience with 104 patients treated for recurrent superficial bladder tumors followed for a mean of 48 +/- 2 months (range 6 to 83 months). Patients received 6 weekly intravesical bacillus Calmette-Guerin instillations, and were followed for response with urinary cytology, cystoscopy and bladder biopsy. Patients were considered treatment failures if either urinary cytology or biopsy results were positive for tumor. Of 69 patients who failed the initial treatment course 60 were given an additional 6-week course of therapy. A 6-week course of bacillus Calmette-Guerin was successful in 19 of 55 patients (35%) treated for prophylaxis, 10 of 32 (31%) treated for carcinoma in situ and 6 of 17 (35%) treated for residual tumor. The response rate for the total patient population treated with 1, 6-week course was 34% (35 of 104). Another 6-week course was successful in 32 of 60 patients (53%). The over-all response rate free of tumor for patients treated with either 6 or 12 weeks of therapy was 64%. The mean interval free of tumor was 48 months. We evaluated tumor type, stage and grade in conjunction with muscle invasion to assess potential indicators of response to a second course of bacillus Calmette-Guerin. Of 13 patients with carcinoma in situ and 45 with papillary disease 5 (38%) and 26 (58%), respectively, responded to a second course of bacillus Calmette-Guerin (not significantly different). In contrast, 5 of 8 carcinoma in situ failures (63%) had muscle invasive disease, compared to only 3 of 19 papillary nonresponders (16%) (p less than 0.02). These results suggest that intravesical bacillus Calmette-Guerin for the treatment of superficial bladder tumors is an effective long-term therapy. One 6-week course may be ineffective for some patients and another 6-week course provides long-term survival free of tumor for many course 1 failures. Patients who present with carcinoma in situ after a single 6-week course of intravesical bacillus Calmette-Guerin have a significantly higher risk for muscle invasive disease than those with recurrent papillary tumors.

The U.S. Environmental Protection Agency (EPA) has developed a “Seven‐Day Fathead Minnow Larval Survival and Growth Test” for measuring the toxicity of effluents. This study evaluated the ease and performance and the intra‐ and interlaboratory variability of this 7‐d test using two reference toxicants (sodium pentachlorophenate and potassium dichromate), two refinery effluents, and one low‐volume internal waste stream from an electric power plant. Ten different laboratories representing academia, private industry, contractors, the state EPA, and the U.S. EPA participated in this study. The reference toxicants were tested twice during two separate test periods, and each effluent and waste stream was tested once. Using EPA's criteria for a successful test, 90% of the 140 planned tests were completed as valid tests. The intralaboratory variability of the survival (LC50) and growth (IC50) results for tests conducted concurrently (spatial variability), expressed as the coefficient of variation (C.V.), ranged between 5.9 and 15.6% and between 9.1 and 26.1%, respectively. The intralaboratory variability of the survival (LC50) and growth (IC50) results for tests conducted at two different times (temporal variability), expressed as C.V., ranged between 14.5 and 25.3% and between 17.6 and 22.7%, respectively. The interlaboratory variability of the survival (LC50) and growth (IC50) results, expressed as C.V., ranged between 24.1 and 43.7% and between 22.4 and 88.0%, respectively. Overall, the variability of the 7‐d fathead minnow test was similar to the variability observed with other toxicity tests and with analytical chemistry measurements of environmental samples.

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