Untreated River Water Research Articles

THE AQUEOUS PHOTOLYSIS OF TRICLOPYR

The aqueous photolysis of triclopyr was examined in both pH 7-buffered water and natural river water under artificial lights and midsummer sunlight (40°N latitude). The pseudo-first-order half-lives in pH 7-buffered water and natural river water averaged 0.5 and 1.3 d, respectively, at 25°C. Diffuse mercury lamps and midsummer sunlight produced similar rates of triclopyr decay and photoproduct distribution for a given solution. The photolysis of untreated river water produced a significantly different distribution of photoproducts compared to sterile, pH 7-buffered water. The photolysis of triclopyr in river water generated oxamic acid as the major photoproduct and a number of other low-molecular-weight carboxylic acids as minor products. Photolysis in sterile, pH 7-buffered water produced 5-chloro-3,6-dihydroxy-2-pyridinyloxyacetic acid as the major photoproduct, with minor amounts of oxamic acid and other low-molecular-weight acids.

The aqueous photolysis of triclopyr

AbstractThe aqueous photolysis of triclopyr was examined in both pH 7‐buffered water and natural river water under artificial lights and midsummer sunlight (40°N latitude). The pseudo‐first‐order half‐lives in pH 7‐buffered water and natural river water averaged 0.5 and 1.3 d, respectively, at 25°C. Diffuse mercury lamps and midsummer sunlight produced similar rates of triclopyr decay and photoproduct distribution for a given solution. The photolysis of untreated river water produced a significantly different distribution of photoproducts compared to sterile, pH 7‐buffered water. The photolysis of triclopyr in river water generated oxamic acid as the major photoproduct and a number of other low‐molecular‐weight carboxylic acids as minor products. Photolysis in sterile, pH 7‐buffered water produced 5‐chloro‐3,6‐dihydroxy‐2‐pyridinyloxyacetic acid as the major photoproduct, with minor amounts of oxamic acid and other low‐molecular‐weight acids.

Kinetic characteristics of the sodium uptake mechanism during the development of embryos and fry of Atlantic salmon, Salmo salar L., in an improved water quality

The kinetics of active sodium uptake in dechorionated embryos, yolk‐sac fry and start‐feed fry of Atlantic salmon were compared in two groups reared either in low conductivity, untreated, river water (conductivity ∼ 46 μS cm−1, pH 5.75), or in ‘improved’ river water buffered with sea water (conductivity ∼2200 μS cm 1, pH 6.56), the latter treatment often being used in commercial hatcheries to avoid problems associated with periodic acidification.Maximal transport rate (Vmax) increased during development in both groups but was always significantly higher in embryos and fry maintained in untreated river water. Values for Km were not seen to vary during development up to 12 weeks after hatching and were not significantly different between groups, or from values reported for adult Atlantic salmon in fresh water.The results are discussed with respect to the influence of Na+ concentrations in the perivitelline fluid of developing eggs and in the external medium surrounding fry on Vmax and Km. The ability of fry reared entirely in buffered river water to maintain sodium balance following transfer to untreated river water is also considered.

Oocyte atresia and reproductive success in fathead minnows (Pimephales promelas) exposed to acidified hardwater environments.

The ovarian histology of fathead minnows (Pimephales promelas) chronically exposed to three levels of environmental pH was examined for evidence of reproductive impairment. Exposures occurred in three experimental running-water channels receiving Mississippi River water. One of these channels was not acidified and two were dosed with H2SO4. The pH was approximately 8 in untreated river water and 6 and 5 in the two channels receiving H2SO4. Fish for ovarian examination were taken from these channels at four stages of the reproductive season: initiation of spawning (June 19), mid-spawning (July 12), end of spawning (August 14-15), and approximately 1 mo. post-spawning (September 19). The fish exhibited ovarian histological changes and depression of reproductive success which were directly associated with the level of environmental stress experienced. The association between these three factors was most consistent and pronounced if the fish were sampled near the end of the spawning season. When sampled at this time, reproductive impairment in a population was found when the ratio of the volume of atretic (resorbing) oocytes present in the ovary to the total ovarian volume exceeded 20% in all fish sampled. This was the case in the pH 5 channel fish sampled in August. At this same time, not all of the fish in the pH 6 channel exhibited such an accumulation of atretic oocytes, and egg deposition in that population was not reduced. None of the fish from the pH 8 channel were so affected nor was their reproduction.

Epidemic non-A, non-B viral hepatitis in Algeria: strong evidence for its spreading by water.

A waterborne epidemic of non-A, non-B hepatitis occurred in Medea, an Algerian town of 68,000 inhabitants during the autumn and winter of 1980-1981. About 6 weeks before the epidemic, there had been a chlorination failure and an accidental sewage contamination of the river water that supplied large parts of the town. From October, 1980, to January, 1981, 788 cases were notified. This epidemic affected mostly young adults, who usually recovered; however, a high rate of mortality was noted among pregnant women (nine patients, nine deaths). Serological examinations performed on 57 hospitalized patients excluded both hepatitis A and B. The waterborne nature of the epidemic was suggested by a study of the case distribution according to water supplies. The epidemic was severe in the areas supplied by the untreated river water. Few cases were reported in the areas receiving spring water, where chlorination never failed. A mild incidence of infection was noted in the areas supplied by a mixture of untreated river water and chlorinated spring water.

Effects of Low Environmental pH on the Survival, Growth, and ionic Composition of Postemergent Atlantic Salmon (Salmo salar)

Postemergent Atlantic salmon (Salmo salar) were reared during the early feeding phase in the soft, acidic water of the Westfield River (mean pH 5.0) in Nova Scotia. The fry were held in a flow-through system of tanks in situ and were fed a hatchery diet. Bioassays were also conducted in river water treated with limestone (mean pH 6.1) to provide a control. Cumulative mortality of fry after 30 d in the tanks was 70% at pH 5.0 and only 4% at pH 6.1. Fry in untreated river water were inactive, ingested little food, and lost weight (approximately 25%) during the first 15 d of exposure. Large increases in body [Ca2+] and [Na+] were observed in fry at both pH levels during that time, but the increase in [Ca2+] lagged and that in [Na+] was less in fry at low pH. Deaths occurred 15–30 d after swim-up and dead fry were all severely emaciated, indicating that deaths were probably from starvation. Although there were differences in ionic composition changes in fry held at pH 5.0 compared with control, no major depletion of body ionic reserves occurred relative to initial concentrations. Surviving fry at pH 5.0 developed a tolerance after 25 d and had growth rates, condition factors, and ionic concentrations similar to those of fry in treated water. The mortality of fry during the transition to exogenous feeding, in response to low pH stress in soft water, is probably responsible for reduced recruitment and the decline or loss of salmon stocks in this and other acidic rivers of Nova Scotia.

Effect of high axial velocity on performance of cellulose acetate hyperfiltration membranes

The effect of axial velocity on performance characteristics of a commercial cellulose acetate membrane was determined in a parallel plate test channel over a 270-fold velocity range, from 0.09 to 24 ft/sec and an applied pressure range of 200 to 1200 psig. Feed was demineralized water or untreated river water spiked with MgCl 2 to give solution concentrations of 0.04 to 0.08 M. At 800 psig system pressure and 24 ft/sec circulation velocity, intrinsic rejection was ∼ 97% and permeability was 0.6 gal/day · ft 2· atm with demineralized water feed spiked with MgCl 2. Substantially no flux decline was observed with demineralized water feed in a 93-hour run at 24 ft/sec. Even with untreated river water feed containing 10–100 ppm suspended solids, flux decline was relatively modest (a slope of -0.03 on a plot of log flux vs. log time) at a circulation velocity of 24 ft/sec. Reduction of circulation velocity to 1.64 ft/sec resulted in a marked decline in flux with time.

Removal of Radionuclides From the Pasco Supply by Conventional Treatment

THE municipal water system of Pasco, Washington, is typical in design of many systems for similar populations and climates. The system is quite unique, however, in that the Columbia River water being treated contains radioactive materials. The presence of radionuclides leads to some interesting considerations not usually found in public water systems. Of these, the radiation exposure of those drinking the water and the reduction of this exposure by removal of nuclides at the treatment plant are of particu‐ lar interest. The nuclides considered here come from the Hanford Atomic Products Operation (HAPO), which is one of the nation's major plutonium production facilities. The plant, located in southeastern Washington, has been operated since 1946 by the General Electric Co. under contract to the AEC. The Pasco treatment facilities are approximately 39 mi downstream from the nearest reactor. Richland, although farther upstream, obtains its raw water from the Yakima River and is therefore not of interest. Kenne‐ wick obtains water from the Columbia River through a collector system which would be more difficult to evaluate in terms of water plant efficiency. A small farming community, Ringold, utilizes Columbia River water for irrigation only. For these reasons, Pasco was chosen to illustrate the distribution of radionuclides in a municipal water system and the radiation exposure to those who drink treated or untreated river water.