Survival of a fecal coliform (Escherichia coli) and a fecal streptococcus (Streptococcus faecalis var. liquifaciens) was studied through several years at shaded and exposed outdoor soil plots. Death rates for both organisms were calculated for the different seasons at both sites. The 90% reduction times for the fecal coliform ranged from 3.3 days in summer to 13.4 days in autumn. For the fecal streptococcus, 90% reduction times were from 2.7 days in summer to 20.1 days in winter. During summer, the fecal coliform survived slightly longer than the fecal streptococcus; during autumn, survival was the same; and in spring and winter the fecal streptococcus survived much longer than the fecal coliform. Both organisms were isolated from storm-water runoff collected below a sampling site when counts were sufficiently high in soil. Isolation was more frequent during prolonged rains, lasting up to 10 days, than during short rain storms. There was evidence of aftergrowth of nonfecal coliforms in the soil as a result of temperature and rainfall variations. Such aftergrowth may contribute to variations in bacterial count of storm-water runoff which have no relation to the sanitary history of the drainage area.

GELDREICH, EDWiN E. (Division of Water Supply and Pollution Control, Cincinnati, Ohio), AND NORMAN A. CLARKE. Bacterial pollution indicators in the intestinal tract of freshwater fish. Appl. Microbiol. 14:429-437. 1966.-A study was made of the occurrence, distribution, and persistence of coliforms, fecal coliforms, and fecal streptococci in the intestinal tract of freshwater fish. A total of 132 fish representing 14 different species were used in various phases of these experiments. Examination of the intestinal contents of 78 fish from moderately polluted sections of the Little Miami River indicated that fecal coliform densities were lowest in bluegills (less than 20 per gram) and highest in catfish (1,090,000 per gram). Levels of fecal streptococci for these two species were 220 and 240,000 per gram, respectively. The occurrence of fecal coliforms in fish caught in this stream reflected the warm-blooded-animalpollution level of the water. All fish used in this phase of the study were caught during July, August, and September when the water temperatures were between 13 and 18 C. The fate of fecal coliforms and Streptococcus faecalis in the fish intestine indicated that these organisms can probably survive and multiply when fish and water temperatures are 20 C or higher, but only when the organisms are retained in the gut for periods beyond 24 hr. Based on the biochemical reactions for 3,877 coliform strains isolated from 132 freshwater fish of 14 different species, 91.4% of all strains were composed of five IMViC types. In a similar study of the biochemical reactions of 850 streptococci isolated from the intestinal tract of 55 freshwater fish, the predominant strains included S. faecalis and various closely associated biotypes. No consistently recurring pattern for either coliforms or streptococci could be developed to identify species of fish investigated. The composition of the intestinal flora is, however, related in varying degree to the level of contamination of water and food in the environment.

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Previous reviews made by Clarke and Chang, and the Task Group 2760 P report pointed out that there was a need for much more quantitative information regarding the fate of human viruses in the environment and water treatment plants. This was particularly true in the matter of filtration, both in the ground and in rapid filters that usually follow flocculation and settling. In an effort to fill some of the gaps, pilot water plant studies were carried out with poliovirus at the R. A. Taft Sanitary Engineering Center for 20 months, and the significant findings to date are presented in this article. The article includes a discussion by Herbert O. Hartung of the St. Louis County Water Company, and also Chairman of the Task Group 2760 P – Viruses in Water. He congratulates the authors for accurately reporting their observations without attempting to draw general and definitive conclusions or to prescribe standards. Because of relatively gross laboratory methods and lack of epidemiological correlations, Task Group 2760 P – Viruses in Water recommends additional studies to show the effect of lime softening and excess lime softening on virus removal. Because of the value of excess lime softening for removing some other protein‐type substances, such a study for virus removal seems appropriate. The task group also recommends that the capacity of activated carbon to absorb viruses be studied.

Four microporous virus-adsorbent filter media for recovering low levels of virus from 380 liters of drinking water were compared. In addition, two of the filter media were compared with 1,900 liters of drinking water. The filter media evaluated were MF nitrocellulose membranes (293 mm), AA Cox M-780 epoxy-fiberglass-asbestos disks (267 mm), K-27 yarn-wound fiberglass cartridges + AA Cox M-780 disks (127 mm), and Balston epoxy-fiberglass tubes (24.5 by 63.5 mm). The filters were used to concentrate seeded poliovirus from 380 liters of finished drinking water. Sodium thiosulfate was added to the drinking water to neutralize chlorine, and hydrochloric acid was added to adjust the pH to 3.5. Virus was eluted from the filters with glycine-NaOH buffer at pH 11.5. In terms of virus recovery efficiency, the filter media ranked Balston > Cox 267-mm > MF 293-mm g K-27 + Cox 127-mm, but differences were slight. The Balston filters and holders were also superior to the other systems in terms of size, weight, cost, and handling factors. Experiments with 2and 8-,gm porosity Balston filters showed no statistically significant difference in virus recovery. Virus was readily detected by the Balston and the MF 293-mm systems at input levels of 12 to 22 PFU/1,900 liters. Preliminary experiments indicated that an elution pH lower than 11.5 may be satisfactory.