The U.S. Geological Survey (USGS) has been recording the changes that have occurred in municipal water utility practices for the last four decades. The scope of the latest study was limited to the 100 largest cities in the United States, as determined by the 1960 census, in order that comprehensive spectrographic and radiochemical analyses could be included. This article presents a summary of the study, including the following information for each of the 100 cities: suburban towns supplied by the city system; population of the city; total population served; sources of supply; auxiliary and emergency sources of supply; if available, the lowest 30‐day mean discharge of streams used for public water supply; treatment; rated capacity of each treatment plant; and, raw‐water and finished water storage capacity. Diagrams have been prepared for 58 cities showing the sources, treatment plants, and areas served by the municipal system. This article provides a list of the 100 largest cities in the U.S., according to the 1960 census, showing population served, sources of public water supply, treatment, and type of raw‐ and treated‐water analyses reported.

Hyaluronic acid (HA) is increasingly used for a number of medical device applications. Since the chemical structure of HA is identical no matter its bacterial or animal origin, it should be the ideal biomaterial. However, short term transient inflammatory reactions are common, while rare long-term adverse events may correlate with subclinical chronic inflammation. Concern has been raised that low molecular weight components or degradation fragments from implanted HA may directly stimulate inflammatory reactions. This study examined a panel of HA molecular weights from the unitary disaccharide up to 1.7 x 10(6) Dalton lengths, in which endotoxin was assayed at a very low level (less than 0.03 EU/mg). The murine cell line RAW 264.7, rat splenocytes, and rat adherent differentiated primary macrophages were assayed for nitric oxide production under a variety of inflammatory conditions plus or minus HA. Under the highest inflammatory states, nitric oxide production was mildly suppressed by HMW-HA while slightly augmented by LMW-HA at mg/mL concentrations. However, at micromolar concentrations fragments below 5000 Daltons, thought to have drug-like qualities, were without effect. These data support the hypothesis that if endotoxin is reduced to an extremely low level, LMW-HA may not directly provoke normal tissue macrophage-mediated inflammatory reactions.

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