Total Residual Chlorine Concentrations Research Articles

Effect of low‐level continuous chlorination on Corbicula fluminea

AbstractThe time required for continuous chlorination to produce 100% mortality in adult Corbicula fluminea was determined. The total residual chlorine concentrations maintained were lower than any previously tested: 0.05, 0.10 and 0.20 mg/L.

Effects of chlorine on microbial communities in naturally derived microcosms: Population and community level responses to environmental perturbations

AbstractLaboratory microcosms and field enclosures were used to evaluate effects of chlorine on microbial community structure and function. Microcosms were exposed to chlorine (as sodium hypochlorite) at concentrations up to 308 μg/L total residual chlorine (TRC) for 28 d. Test systems were sampled weekly to evaluate protozoan species accrual, biomass distribution, microbial enzyme activity, and macronutrient retention. Protozoan species numbers were depressed at all sampling times at TRC concentrations ≥25 μg/L. Algal biomass (chlorophyll a) was adversely affected at 2 μg/L, and alkaline phosphatase activity was inhibited at ≥6 μg/L. Other biomass measures and macronutrient retention were affected at 25 to 308 μg/L. Oxygen production was depressed at ≥25 μg/L. Field enclosures (sediment‐water mesocosms) were dosed daily with chlorine, resulting in average chlorine doses up to 261 μg/L. Protozoan species numbers were depressed at chlorine doses ≥79 μg/L, and zooplankton density was affected at 24 μg/L. Algal biomass and total biomass were adversely affected at the highest chlorine level, 261 μg/L. Nontaxonomic measures were typically less sensitive than community structure responses to chronic chlorine stress. Estimated effect levels for both experiments overlapped; however, the response of specific variables (i.e., stimulation, inhibition, no effect) to chlorine differed between the two tests. These results support the importance of experimental design and dosage regime in chronic toxicity testing.

Hatching of the Pacific salmon leech ( Piscicola salmositica) from cocoons exposed to various treatments

Cocoons of Piscicola salmositica deposited on rocks (3–4 cm in diameter) by captive leeches were incubated in tanks supplied with continously flowing well water at 8–10°C from November 1984 to February 1985. The percentage of leeches that hatched from cocoons that were treated with either a total residual chlorine (TRC) concentration that decreased from 602 to 94 μg/l during the 24-h exposure period (64% hatched) or a 1 10 dilution of stock iodophore disinfectant (Wescodyne ®) for 10 min (63% hatched) was not statistically different from the percentage that hatched from untreated control cocoons (53% hatched). The percentage of leeches that hatched from cocoons treated with TRC concentration that decreased from 52 to 4 μg/l during the 24-h exposure period (78% hatched) was significantly increased over that of the controls. A statistically significant reduction in the percentage of cocoons that hatched occurred after exposure to air at 20°C and 80% relative humidity for 24 h (23% hatched). No leeches hatched from cocoons subjected to freezing in or out of water at −5°C for 7 days, exposed to air at 16–20°C and 75–84% relative humidity for 7 and 28 days, or exposed to a 1 10 dilution of a 10.8% sodium hypochlorite solution for 10 min. Leeches hatched over a period of about 152 days with peak hatching during October. Despite exposure of cocoons to various treatments and incubation in well water at 8–10°C from the day the cocoons were deposited until the experiment was terminated (29 November 1984–18 February 1986), and incubation in almost total darkness for the last 238 days, the emergence of leeches in the experiment was synchronous with the hatching of “wild” leeches in the field.

Potential Usefulness of Chlorine for Controlling Pacific Salmon Leeches, Piscicola salmositica, in Hatcheries

Susceptibility to the lethal effects of low levels of total residual chlorine (TRC) differed between juvenile coho salmon (Oncorhynchus kisutch) and the salmon leech (Piscicola salmositica), the vector for the haemoflagellate salmonid pathogen Cryptobia salmositica. There was no salmon mortality at concentrations below approximately 50 μg TRC/L for the maximum exposure time of 24 h. Some damage to gill tissue (hypertrophy, fusion, oedema, and some necrosis), was observed at the highest concentrations of TRC that did not kill any of the fish (approximately 50 μg/L for 24 h, and approximately 100 μg/L for 8 h). This damage was repaired by the fish within 4 d of exposure, although evidence of past irritation was noted in 6 of 12 fish. All small juvenile leeches exposed to 44 μg TRC/L for 24 h died, and over half of such leeches exposed to 44 μg/L for 8 h and 21 μg/L for 24 h died. Below TRC concentrations that were lethal to the fish (approximately 50 μg/L), contours of constant leech mortality derived from a logistic regression model fitted to the data offered a wide range of concentrations and exposure times that would result in high mortality of juvenile leeches. Larger subadult and adult leeches were more resistant to chlorine than the smaller leeches but were more sensitive than the juvenile fish. Thus, chlorine may prove useful for controlling P. salmositica in salmonid hatcheries.

Sewage effluent biomonitoring: I. Survival, growth, and histopathological effects in channel catfish

A 17-day, in situ, biomonitoring study using caged, juvenile channel catfish ( Ictalurus punctatus) was conducted at five sites along a 9-km section of the Flint River at the Anthony Ragnone Wastewater Treatment Plant near Montrose, Michigan. Effects on survival, growth, and gill and liver histopathology were examined. No differences in growth, measured as wet weight gain, were observed between upstream control (UP) and experimental fish located 9 km downstream from the outfall (Down 4). Acute, 100% mortality occurred at study sites 300 and 500 m downstream from the outfall (Down 1 and Down 2, respectively). Mortality was probably due to excessive mean total residual chlorine concentration (0.24 and 0.30 mg/liter at Down 1 and Down 2, respectively). No mortality was observed at the remaining study sites. Forty percent of the fish at UP had slight hyperplasia and hypertrophy of the respiratory epithelium. All fish at Down 4 had two or more moderate to severe histopathological damages to the gills, including severe hyperplasia of the epithelial cells, clubbing and fusion of the secondary lamellae, moderate to severe edema in the secondary lamellae, and multiple, blood-filled aneurysms. Thirty-eight percent of livers from the UP fish were extremely vacuolated compared to 60% of the Down 4 fish livers. Both the vacuolated and less vacuolated (dense) liver sections stained negatively for lipids with oil red O. The vacuolated liver sections were qualitatively more intense than the dense sections when stained with Best's carmine. Vacuolated liver sections stained negatively with Best's carmine when pretreated with amylase, thereby indicating that the vacuolation represented glycogen storage. There was no correlation between the histopathological changes and any deleterious effects on growth or survival during the 17-day exposure. However, the gill histopathological changes would likely increase susceptibility to bacterial gill disease, and cause a reduction in the scope for activity due to impaired oxygen diffusion in the gills.

Detoxification rates of chlorinated solutions as determined by the half‐life of biological activity withDaphnia magna

AbstractData are presented that discourage the use of total residual chlorine (TRC) and free residual chlorine (FRC) levels in setting water quality criteria for chlorine and chlorinated carrier molecules. Repetitive static acute toxicity tests for aging solutions of chlorinated complexes withDaphnia magnapermit generation of biological half‐lives for direct comparison with analytically derived concentrations of TRC and FRC. The results indicate a strong similarity in the decline of toxic effects onD. magnaand TRC for an aging solution of 1,3‐dichloro‐5,5‐dimethylhydantoin (DCDMH), although no such similarity exists between these two measures for aging solutions of chlorine and trichloro‐S‐triazinetrione (TCTT). Repetitive toxicity tests with aging DCDMH generated toxic decay curves with coefficients of determination (r2) exceeding 73% while exhibiting a minimum decay rate of ‐0.10. TRC data for DCDMH exhibited anr2of 93% and a decay rate of ‐0.07. Ther2values for the chlorine series ranged from 15 to 60% for the toxic effects decay curve, as compared with 76% for analytically derived data. The TCTTr2values for these same parameters were 23 to 64 and 84%, respectively. Both chlorine and TCTT presented definable, consistent decreases in TRC levels over the course of the studies, while the observed biological effects oscillated widely from test to test within a series. These results demonstrate that the standard reported parameters of TRC and FRC are inadequate for setting effluent limitations on chlorinated discharges because they are inconsistent in measuring the toxic constituents of these solutions.

Influence of Chlorine on the Susceptibility of Striped Bass (Morone saxatilis) to Vibrio anguillarum

Exposure of striped bass (Morone saxatilis) for 96 h to sublethal concentrations of total residual chlorine (TRC) (0.05–0.23 mg/L) did not increase their susceptibility to infection with the bacterial pathogen Vibrio anguillarum. Variables examined were TRC concentrations, length of exposure to chlorine, and the order of exposure to chlorine and the pathogen. Mortalities in the groups exposed to both chlorine and pathogen were not significantly different from those seen in groups receiving the bacteria only. The LD50 of V. anguillarum for striped bass was influenced by the water temperature as well as the size and immune status of the fish.

THE INFLUENCE OF SPRING AND FALL TEMPERATURES ON THE AVOIDANCE RESPONSE OF JUVENILE ATLANTIC MENHADEN, BREVOORTIA TYRANNUS, EXPOSED TO SIMULTANEOUS CHLORINE‐δT CONDITIONS1

ABSTRACT: The avoidance response of groups of juvenile Atlantic menhaden, Brevoortia tyrannus, was evaluated by exposing test species to a range of simultaneous total residual chlorine (TRC) (0.00, 0.05, 0.10, and 0.15 mg/L) and elevated temperature (0, 2, 4, and 6°C) conditions simulating power plant discharges. This species was tested at both 15 and 20°C to determine possible effects of acclimation temperature on the avoidance response. These temperatures were selected to represent spring or fall thermal conditions when most East Coast power plant facilities initiate power plant chlorination in the spring or terminate the use of this biocide in the fall. An unbalanced 3‐factor factorial design was used to develop response surface avoidance models at 15 and 20°C. The model developed at 15°C showed: (1) an increase in avoidance occurred at all δT conditions as TRC increased from 0.00 to 0.05 mg/L; (2) a greater degree of avoidance occured at TRC concentrations above 0.05 mg/L at all δT conditions; and (3) TRC was the most important term inflencing avoidance. The model for Atlantic menhaden at 20°C showed: 1) avoidance increased with increasing TRC concentration at each δT condition; (2) avoidance did not necessarily increase with increasing δT's at each TRC concentration; (3) greatest avoidance occured at 0°C δT and 0.15 mg/L TRC; and (4) TRC was the most important term influencing avoidance. There was a significant difference (p < 0.00001) between avoidance models at 15 and 20°C. However, when extreme conditions of 0.15 mg/L TRC and 0–6°δT were compared, the degree of avoidance responses (percent time in control area) was similar.

Factors affecting the amperometric determination of trace quantities of total residual chlorine in sea water

The standard scheme for the determination of total residual chlorine in seawater by amperometric titration is not suitable for many recent studies that require lower and lower detection limits (<0.1 mg L/sup -1/ or <1.4 ..mu..equiv L/sup -1/). The interference of iodate that originated from the reaction between iodide and hypobromite and from naturally occurring iodate in seawater may yield variable blank and/or grossly underestimated results. The pH chosen in the present analytical scheme is at a value where the reaction between iodate and iodide is sluggish and the extent to which iodate is converted to triiodide is most sensitive to small pH changes. A titration at pH 2 will yield the true concentrations of total residual chlorine after the contribution from naturally occurring iodate is corrected for. The interference from nitrite should be considered if a submilligram per liter level of residual chlorine is to be measured and/or if the titration is carried out at a pH below 3. This interference may be removed by the addition of sulfamic acid.

Acute metabolic responses of lotic epilithic communities to total residual chlorine.

Numerous workers have examined the effects of chlorine on individual e p i l i t h i c community components (e.g. , CAIRNS & PLAFKIN 1975; BROOKS & LIPTAK 1979), but l i t t l e attent ion has been given to the effects of residual chlorine on the whole l o t i c e p i l i t h i c community. Ep i l i t h i c organisms are those microf loral and fauna assemblages l i v ing on the surface of rocks; the primary cons t i t uents include bacteria, algae, fungi, and protozoans. Ep i l i t h i c communities are an important functional component of aquatic ecosystems. Thus, deter iorat ion of the community due to the introduction of a stress agent could dras t ica l l y impair the functional capabi l i t ie~ of the ent i re system. As the respirat ion rates of biological systems are re f lec t ive of energy flow through the system, and primary product iv i ty is a measure of carbon f ixat i o n c a p a b i l i t i e s , the purpose of th is invest igat ion was to determine the acute metabolic responses of l o t i c e p i l i t h i c communities to various concentrations of total residual chlorine (TRC).

Comparison of Laboratory and Field Avoidance Behavior of Fish in Heated Chlorinated Water

Abstract The effects of intermittent chlorination and temperature selection on the movement of fish were studied in an integrated field and laboratory project on the New River at the Glen Lyn Power Plant in southwestern Virginia. Over a temperature range of 7–36 C, the total number of fish sampled from the intermittently chlorinated thermal effluent was lower than control values (P ⩽ 0.09) when total residual chlorine (TRC) concentrations were ⩾ 0.15 mg/liter. After seasonal variations were segregated into discrete intervals of field temperature and fish avoidance of TRC, a decline in fish abundance in the chlorinated, heated discharge was observed within 95% confidence limits. In summer field temperatures of 27–30 C, fish avoided a TRC concentration that ranged from (95% confidence limits) 0.19 to 0.28 mg/liter TRC; when temperatures were falling from 26 to 7 C, they avoided 0.23–0.42 mg/liter TRC. The two most consistently sampled fish species, spotfin shiner Notropis spilopterus and whitetail shiner N....

The effect of total residual chlorine on the respiration rates of two species of freshwater leech (hirudinoidea)

1. The effect of chlorine on the respiration rates of Erpobdella punctata (Leidy) and Nephelopsis obscura (Hirudinoidea) was investigated at total residual chlorine concentrations ranging from 0.00 to 8.00 mg/1 at both 10 and 15C. 2. Both species displayed a similar pattern of respiratory response at 10 and 15°C with a decrease in respiration at low chlorine concentrations followed by an increase in respiration at medium concentrations and a decreased respiration rate at high chlorine concentrations. 3. The pattern of respiratory response shown by the leeches appears to be related to the differences in activity in different chlorine concentrations. 4. The respiration rates of both species were significantly higher at 15°C than at 10°C, but little difference occurred in the respiration response with chlorine concentrations.

Avoidance response of rainbow trout ( Salmo gairdneri) to single-dose chlorination in a power plant discharge canal

Rainbow trout ( Salmo gairdneri) were exposed to 20 min single-dose chlorine additions designed to achieve maximum total residual chlorine (TRC) concentrations of 0.04, 0.2, 0.6, and 1.0 mg l −1. First retreats from the chlorine front occurred at 0.05 mg l −1 TRC. Approximately 95% of the fish had moved downstream when TRC reached 0.5 mg l −1, well before cumulative time-dose exposure approached lethal limits. Percentage of fish remaining near the discharge decreased linearly as TRC concentration rose, suggesting that a rapid rise in receiving water chlorine level might be beneficial in reducing cumulative time-dose exposure. Rainbow trout demonstrated the initial sensitivity to avoid lethal chlorine exposure, but complete assessment of the utility of the avoidance response must also consider distribution throughout chlorination and the potential for repeated exposure.

The effect of intermittent chlorination on freshwater phytoplankton

Lake Michigan phytoplankton showed a significant loss of chlorophyll a and permanent reduction of carbon uptake rates after exposure for 30 min to concentrations of total residual chlorine at or above 1 mg l −1. At this level the photosynthetic system of the algae was irreversibly destroyed. Below 0.1 mgl −1 total residual chlorine only slight changes in chlorophyll a were noted, and, following an initial decrease, carbon uptake rates exhibited nearly complete recovery after 24 h.

The recovery and hematological rehabilitation of chlorine stressed adult rainbow trout (Salmo gairdneri)

The ability of adult rainbow trout (Salmo gairdneri) to recover from acute chlorine exposure was tested. Six separate tests were carried out in duplicate. Blood was collected from each duplicate group of fish at the beginning of the test, at the appearance of the chlorine-distress symptoms, and at 24 and 48 h after exposures. The total residual chlorine (TRC) concentrations used in these six tests were 1.67, 3.50, 1.10, 1.25, 1.02 and 0.0 mg 1−1, at water temperatures of 13.5, 14.6, 17.2, 22.6, 23.0 and 26.0° C, respectively. The cumulative fish mortality for these six tests at 48 h after exposure were 11.5, 100, 0.0, 67.1, 36.1 and 100 percent. Blood of chlorine stressed fish exhibited signs of hemoconcentration and hemolysis. All blood parameters with the exception of hemolysis returned to control levels within 24 hours after exporsure. High TRC concentrations in the range of 3.5 mg 1−1 at 14.0° C, and TRC of 1.25 and 1.02 mg 1−1 TRC at 23° C, significantly diminished the rainbow trout recovery.

Chlorine Effects on Larval Development of Striped Bass (Morone saxatilis), White Perch (M. americana) and Blueback Herring (Alosa aestivalis)

Abstract Eggs of striped bass (Morone saxatilis), white perch (M. americana) and blueback herring (Alosa aestivalis) were exposed to a series of total residual chlorine (TRC) concentrations until hatch occurred. Larval development of the three species was inhibited by increasing TRC concentrations. Length of larval fish at hatch decreased with increasing TRC concentrations and the production of abnormal blueback herring larvae increased with increasing TRC concentrations.

Toxicity of intermittent chlorination to bluegill, Lepomis macrochirus: interaction with temperature.

Ten juvenile bluegill which were acclimated in aquaria to each test temperature (6, 15, 25, and 32 C) for a minimum of 2 weeks were placed in each bioassay container and further acclimated for 48 h before chlorine exposure. A laboratory system was built to simulate the pattern of changes in chlorine concentration of water below a steam-electric generating plant. Chlorine, as calcium hypochlorite, was added to achieve peaks of total residual chlorine concentration of 0.21, 0.31, 0.41, and 0.52 mg/1, respectively, in each of 4 aquarium at the temperatures used in the test. Although there were no deaths at 0.2 mg/1 peak total chlorine, the behavior of the fish exposed at the two highest temperatures indicated that they were under stress. The threshold of 0.3 mg/1 peak total chlorine observed in the study, at which chlorine becomes toxic to bluegills, is rather distinct. (MFB)

Factors affecting the use of chlorine in the spin‐chilling of eviscerated poultry

Synopsis Conditions have been determined under which chlorination can be used to eliminate both faecal and spoilage bacteria from the water used for chilling eviscerated poultry carcasses, thus avoiding any hazard from cross‐contamination. All combinations of three rates of water usage (2.5, 5 or 8 1 per carcass) and three concentrations of total residual chlorine (10 to 15, 25 to 30 or 45 to 50 ppm), obtained by the addition of sodium hypochlorite, were compared. It was found that the majority of bacteria present were destroyed by the use of 45 to 50 ppm of total chlorine in conjunction with 5 1 of water per carcass. When the rate of water usage was increased to 8 1 per carcass it was found that 25 to 30 ppm of residual chlorine in the chill‐water gave comparable results. The effect of water usage on the concentrations of free residual chlorine present in the chill‐water during processing is discussed. When chlorine gas was added continuously at a fixed concentration to the input water the concentration of total residual chlorine decreased in each chiller. This method of chlorination was found to be less effective in destroying bacteria than the hypochlorite method which could be used to vary the amount of added chlorine in order to maintain the required total residual concentration during processing.