Acute and chronic toxicity of lead to rainbow trout salmo gairdneri, in hard and soft water

Lead was found to be highly toxic to rainbow trout in both hard water (hardness 353 mg l⁻¹ as CaCO₃) and soft water (hardness 28 mg l⁻¹. Analytical results differ greatly with methods of analysis when measuring concentrations of lead in the two types of water. This is exemplified in LC50's and maximum acceptable toxicant concentrations (MATC's) obtained when reported as dissolved lead vs total lead added in hard water. Two static bioassays in hard water gave 96-h LC50's of 1.32 and 1.47 mg l⁻¹ dissolved lead vs total lead LC50's of 542 and 471 mg l⁻¹, respectively. In a flow-through bioassay in soft water a 96-h LC50 of 1.17 mg l⁻¹, expressed as either dissolved or total lead, was obtained. From chronic bioassays, MATC's of lead for rainbow trout in hard water were between 18.2 and 31.7 μg l⁻¹ dissolved lead vs 120–360 μg l⁻¹ total lead. In soft water, where exposure to lead was initiated at the eyed egg stage of development, the MATC was between 4.1 and 7.6 μg l⁻¹. With exposure to lead beginning after hatching and swim-up of fry, the MATC was between 7.2 and 14.6 μg l⁻¹. Therefore, fish were more sensitive to the effects of lead when exposed as eggs.     

Detoxification of seawater used for gas scrubbing in the steel industry

Cyanide ion present in seawater after scrubbing blast furnace and coke ovens gases can be removed by sedimentation of hexacyanoferrate complexes followed by oxidation of residual cyanide with Caro's acid. Zinc ion is removed at the same time by adsorption on the hexacyanoferrate/hydrous ferric oxide precipitate.Sulphide is precipitated as ferrous sulphide, then oxidised by atmospheric oxygen. At 25°C and using an Fe/CN ratio of 1·00, initial concentrations of 50 mg l⁻¹ of CN⁻ and 10 mg l⁻¹ of Zn²⁺ in seawater are reduced to 5–7 mg l⁻¹ and 0·1 mg l⁻¹. Subsequent treatment with H₂SO₅/CN = 1·2 reduces the [CN⁻] to 0·1 mg l⁻¹.Treatment of a combined blast furnace/coke ovens effluent ([CN⁻] = 24 mgl⁻¹, [Zn²⁺] = 4·0 mgl⁻¹) with Fe/CN = 1·5 reduced [CN⁻] to 0·2 mg l⁻¹ and [Zn²⁺] to <0·1 mgl⁻¹. Subsequent treatment with H₂SO₅/CN = 2·0 reduced [CN⁻] to 0·2 mg l⁻¹. The process operates best in the pH range 7–9 and so is not affected by the buffer characteristics of seawater.     

Chronic toxicity of vanadium to flagfish

The 96-h LC50 of vanadium to adult American flagfish (Jordanella floridae) was 11.2 mg l⁻¹ in very hard water. Larvae showed 28-day LC50's of 1.13 and 1.88 mg l⁻¹ of vanadium with larger larvae being more resistant. These appeared to be thresholds of lethality. During continuous exposure for 96 days, larval growth and survival were the most sensitive indicators of vanadium toxicity and were marginally reduced at 0.17 mg l⁻¹. At 0.041 mg l⁻¹, there were no deleterious sublethal effects but there was definite stimulation of growth in females and of reproductive performance. The threshold for chronic toxicity was judged to be about 0.08 mg l⁻¹. The “safe”-to-lethal ratio was 0.007 and this could be used as an application factor for other species. There was no clear evidence that vanadium had any long-term cumulative toxicity.     

The toxic effects of trinitrotoluene (TNT) and its primary degradation products on two species of algae and the fathead minnow

The effects of alpha trinitrotoluene (alpha TNT) and its primary degradation product (TNTcc), commonly referred to as “pink water”, were determined on members of two trophic levels. The growth responses of the algae Selenastrum capricornutum and Microcystis aeruginosa were examined through static bioassays. Death and behavioral responses of the fathead minnow (Pimephales promelas) were determined using a proportional diluter. Alpha TNT and TNTcc were both more toxic to the fathead minnow than to either species of alga. Five and 15 mg l⁻¹ alpha TNT inhibited S. capricornutum and M. aeruginosa growth, respectively. TNTcc inhibited S. capricornutum growth at concentrations above 9 mg l⁻¹; it was lethal to M. aeruginosa at 50 mg l⁻¹, but stimulated growth at lower concentrations. The 96-h lc₅₀ values based on the death response of the fathead minnow to alpha TNT and TNTcc were 2.58 and 1.60 mg l⁻¹, respectively. The 96-h ec₅₀ values based on the behavioral responses were 0.46 and 0.64 mg l⁻¹, respectively. There was no response to concentrations of 0.05 mg l⁻¹ alpha TNT and 0.07 mg l⁻¹ TNTcc.     

Acute and chronic toxicity of copper to the fathead minnow in a surface water of variable quality

Acute and chronic toxicity tests conducted with the fathead minnow and copper used as the source of dilution water a natural stream to which a sewage treatment plant upstream contributed a variety of materials known to affect acute copper toxicity. Nominal total copper 96-h median tolerance limit values (96-h TL50), determined with static testing procedures, ranged from 1.6 to 21 mg l⁻¹. Dissolved copper 96-h TL50 values ranged from 0.60 to 0.98 mg l⁻¹. The maximum acceptable toxicant concentration (MATC) based on survival, growth, reproduction, and hatchability of eggs was between 0.066 and 0.118 mg l⁻¹.     

Lethal and sublethal exposure and recovery effects of ozone-produced oxidants on adult white perch (Morone americana Gmelin)

Adult white perch (Morone americana), acclimated to 15°C, were exposed to a series of ozone-produced oxidant (OPO) concentrations for 96 h using continuous flow bioassay techniques. Toxicity data were analyzed using both response surface modeling and standard probit regression. White perch were also exposed to a series of near and sublethal OPO concentrations, selected from the acute toxicity study, for 96 h and then placed in clean non-ozonated water for 14 days. Blood pH, hematocrit and gill histopathology were analyzed during exposure at 24, 48 and 96 h and after 4 and 14 days in the recovery period. Blood pH and hematocrit levels were analyzed statistically using standard ANOVA and multiple range tests. Histopathological effects were examined using both light microscopy and scanning electron microscopy. The 24-, 48- and 96-h LC₃₀'s were 0.38, 0.26 and 0.20 mg OPO l⁻¹, respectively. Blood pH was significantly reduced at concentrations 0.15 mg OPO l⁻¹ but not at 0.10 mg l⁻¹ or lower concentrations. Hematocrit significantly increased at concentrations 0.10 mg OPO l⁻¹. Histopathological examination revealed minimal effects on gill tissue at 0.01 mg OPO l⁻¹, moderate epithelial sloughing and heavy mucus production at 0.05 mg OPO l⁻¹ and extreme tissue damage at concentrations 0.10 mg l⁻¹. Results from both the acute toxicity and the exposure and recovery study were compared with the effects of chlorine-produced oxidants (CPO) obtained from the literature. Both OPO and CPO appear to have similar effects on adult white perch.     

Toxic effects of hexavalent chromium on brook trout (Salvelinus fontinalis) and rainbow trout (Salmo gairdneri)

Exposing brook trout to various concentrations of chromium [Cr(VI)] for up to 22 months (including reproduction) significantly increased alevin mortality at 0.35 mg Cr l⁻¹ and retarded growth of young brook trout at the lowest concentration tested (0.01 mg Cr l⁻¹). Eight month exposures of rainbow trout significantly increased alevin mortality at 0.34 mg Cr l⁻¹ and also retarded growth at the lowest concentration tested (0.10 mg Cr l⁻¹). Exposures of brook trout lasting 22 months showed, however, that growth was only temporarily affected, and therefore, it was not used as an end point to measure the affects of chromium on either species. Reproduction, and embryo hatchability of brook trout were unaffected at Cr(VI) concentrations that affected survival of newly hatched alevins. The maximum acceptable toxicant concentration (MATC) for brook and rainbow trout exposed to Cr(VI) in water with a hardness of 45 mg l⁻¹ (as CaCO₃) and a pH range of 7–8 lies between 0.20 and 0.35 mg Cr l⁻¹. The 96-h lc₅₀ for brook and rainbow trout was 59 and 69 mg Cr l⁻¹, respectively: therefore, the application factor (MATC/96-h lc₅₀) for both species lies between 0.003 and 0.006.     

The growth inhibition of planktonic algae due to surfactants used in washing agents

A survey of inhibitory effects of nonionic and anionic surfactants, including a soap, used in washing agents, on the growth on three species of freshwater phytoplankton, Selenastrum capricornutum, Nitzschia fonticola and Microcystis aeruginosa was conducted. Based on the specific growth rate, μu estimated from a short period (2 or 3 days) cultivation of test algae, the growth inhibition was determined using EC₅₀ values where μu in the culture medium with surfactant decreased 50% of that without surfactant.The EC₅₀ values of nonionic and anionic surfactants tested here for S. capricornutum ranged from 2 to 50 mg l⁻¹ and from 10 to 100 mg l⁻¹, respectively. The tolerances of three species of algae tested with three surfactants, LAS, AE (EO:9) and soap, were different and the inhibitory effects were species specific. EC₅₀ values of LAS, AE (EO:9) and soap for S. capricornutum were 50–100, 4–8 and 10–50 mg l⁻¹, respectively. Those for N. fonticola were 20–50, 5–10 and 20–50 mg l⁻¹, and those for M. aeruginosa were 10–20, 10–50 and 10–20 mg l⁻¹, respectively.     

Toxicity-, accumulation- and elimination studies of α-hexachlorocyclohexane (α-HCH) with saltwater organisms of different trophic levels

A short-term study with α-HCH was carried out with saltwater organisms of different trophic levels the alga—Dunaliella, the crustacean—Artemia, and the fish—Lebistes, acclimated to water of gradually increased salinity.Within the solubility range of α-HCH in saltwater (1.4 mg l⁻¹) there was no influence on the growth of Dunaliella. The LC50 (4 days) for Artemia was 0.5 mg l⁻¹, the EC50 (2 and 4 days)—E = mortality and immobilization, for Lebistes was 1.4 and 1.3 mg l⁻¹ respectively. In the longterm study the LC10 (35 days) for Lebistes proved to be 0.5 mg l⁻¹.In the accumulation studies the concentration factor was about 60–90 with Artemia and about 500 with Lebistes; equilibrium levels were reached within 24 and 48 h respectively. In the elimination studies the α-HCH concentration was halved within 48–72 h in Artemia and within 10 h in Lebistes.     

The acute toxicity of vanadium and copper to eyed eggs of rainbow trout (Salmo gairdneri)

The effects of vanadium (25–595 mg l⁻¹) and of copper (0.03–4.78 mg l⁻¹) on embryonic survival and hatching of eyed eggs of rainbow trout, Salmo gairdneri, were investigated. Copper was approx. 300-fold more toxic than vanadium (96-h LC₅₀ = 0.4 and 118 mg l⁻¹, respectively) but had little effect on the timing of hatch. Vanadium induced premature hatching of eyed eggs at concentrations from 44 to 595 mg l⁻¹. Concentrations of copper required to produce lethality in eyed eggs were similar to concentrations required to produce mortality in juveniles. Vanadium concentrations approx. 15 times higher were required to produce mortality in eyed eggs than in juveniles. Therefore, acute exposure of eyed rainbow trout eggs to vanadium is not a sensitive toxicity test for use in establishing water quality criteria or maximum acceptable toxicant concentrations.     

Lethal toxicity of permethrin (NRDC-143) to rainbow trout, salmo gairdneri, in relation to body weight and water temperature

Lethal toxicity of permethrin varied inversely with water temperature and body weight. The 96 h LC 50 (median lethal concentration) for 1 g trout increased by an order of magnitude from 0.62 to 6.43 μg 1⁻¹ between 5 and 20°C. However between 5 and 10°C the 96 h LC 50 changed little from 0.6 μg 1⁻¹. Large trout (200 g) were considerably more tolerant to permethrin than small fish. Thus, the 96 h LC 50s for 1 and 200 g trout were 3.17 and 314 μg 1⁻¹ respectively at 15°C. The size effect was most pronounced between 1 and 50 g.It is to be noted that the application of permethrin for insect control coincides with the usual period of emergence of rainbow trout fry subsequent to a spawning period of April to late June.     

Comparison of chlorine and chlorine dioxide toxicity to fathead minnows and bluegill

The comparative toxicity of total residual chlorine (TRC) and chlorine dioxide (ClO₂) was evaluated by conducting 96 h flow-through bioassays with three types of fish. The fish were subjected to an intermittent exposure regime in which biocide residuals were present for approx. 2-h periods beginning at 0, 24, 48 and 72 h into the tests. These conditions simulated the antifouling procedure (1 h day⁻¹ biocide addition) used to control biofouling of nuclear reactor heat exchangers at the Savannah River Plant near Aiken, South Carolina. LC₅₀ values showed that ClO₂ was approx. 2–4 times more toxic than TRC to: (1) juvenile and 1-year-old fathead minnows (Pimphales promelas); and (2) young-of-the-year bluegill (Lepomis macrochirus).The TRC mean 96-h LC₅₀ values were: 0.08 mg l⁻¹ for juvenile fathead minnows, 0.35 mg l⁻¹ for adult fathead minnows and 0.44 mg l⁻¹ for young-of-the-year bluegills. The ClO₂ mean LC₅₀ values were: 0.02 mg l⁻¹ for juvenile fathead minnows, 0.17 mg l⁻¹ for adult fathead minnows and 0.15 mg l⁻¹ for young-of-the-year bluegills.     

Preliminary studies on the leaching of some trace metals from kitchen faucets

Preliminary studies were carried out on the leaching of copper, zinc, chromium, cadmium and lead from eight kitchen faucets by samples of raw, filtered and distributed Ottawa water, a sample of well water and deionized water containing 2 mg l⁻¹ aqueous fulvic acid. Leaching was effected by allowing the test solutions to stand in the inverted faucets for two successive 24-h periods. Concentrations of the metals found in the leachates were copper: first leaching, 0.12–28.0 mg l⁻¹, second leaching, 0.08-3.54 mg l⁻¹; zinc: first leaching, 0.13-10.25 mg l⁻¹, second leaching, 0.06-2.85 mg l⁻¹; chromium: first leaching, < 1.0 × 10⁻³ − 0.395 mg l⁻¹, second leaching, < 1.0 × 10⁻³−0.032 mg l⁻¹; cadmium: first leaching, < 0.05 × 10⁻³−0.01 mg l⁻¹, second leaching, < 0.05 × 10⁻³−4 × 10⁻³ mg l⁻¹; and lead: first leaching, < 0.2−110.0 mg l⁻¹, second leaching, < 0.2−82.0 mg l⁻¹. The faucets containing lead-soldered copper joints released high concentrations of lead, particularly in the case of leaching with the aqueous fulvic acid solution. Under the conditions of the present investigations it is indicated that in some cases the concentrations of metals leached could lead to intakes in excess of the maximum permissible limits for these metals. However, further investigations will be required to determine the possible contribution of these faucets to metal intake under normal usage.     

Acute toxicity and behavioral responses of coho salmon (Oncorhynchus kisutch) and shiner perch (Cymatogaster aggregata) to chlorine in heated sea-water

The acute toxicity and behavioral response to chlorinated and heated sea-water was determined for coho salmon smolts and 1–3 month old shiner perch. LC₅₀'s were determined for 7.5, 15, 30 and 60 min exposure times; 13, 16 and 20°C (Δt = 0, 3, 7°C) temperatures and total residual oxidant (TRO) concentrations ranging from 0.077 to 1.035 mg l⁻¹. The mean 60 min LC₅₀ for shiner perch was significantly reduced (P ≤ 0.05) from 308 μg l⁻¹ TRO at 13°C to 230 μg l⁻¹ TRO at 20°C. The 60 min LC₅₀ for coho salmon decreased from 208 μg l⁻¹ TRO at 13°C to 130 μg l⁻¹ at 20°C. The LC₅₀'s for coho salmon in chlorinated sea-water averaged 55% of those for shiner perch. The relationship between TRO concentration, exposure time, and percent survival in chlorinated sea-water at 13°C is presented for both species.A significant (P ≤ 0.01) avoidance threshold for coho salmon occurred at 2 μg l⁻¹ TRO and was reinforced with increasing temperature. A significant (P ≤ 0.01) avoidance threshold for shiner perch occurred at 175 μg l⁻¹ TRO, while a significant preference (P ≤ 0.05 or 0.01) response at 16°C and 20°C occurred at 10, 25, 50 and 100 μg l⁻¹ TRO. The ecological implications of the toxicity tests and the behavioral responses are discussed.     

The toxicity of various mining flotation reagents to rainbow trout (Salmo gairdneri)

Preliminary testing of eight collectors (xanthates) and four frothers in 96-h static and 28-day flow-through bioassays using rainbow trout as the test organism show a great disparity in the toxicity of the chemicals administered in these two ways.For the short-term tests, the relative toxicity of the compounds is expressed as an lc₅₀ or as a range of concentration in mg l⁻¹ in which the lc₅₀ is expected to fall. Of the collectors tested in this way sodium ethyl and potassium amyl xanthate were the most toxic, with lc₅₀'s in the range of 30–50 mg l⁻¹. Among the frothers, xylenol (cresylic acid) was found to be the most toxic (5.6 mg l⁻¹ >lc₅₀ > 3.2 mg l⁻¹) while polypropylene glycol was least toxic (lc₅₀ > 1000 mg l⁻¹).The long-term tests using potassium ethyl, sodium isopropyl, sodium ethyl, and potassium amyl xanthate indicated that in the flow-through system, the toxicity of the chemicals was in the order of 100 fold greater compared with the static bioassay results.     

The use of uric acid as a method of tracing domestic sewage discharges in riverine, estuarine and coastal water environments

The chemical tracking of sewage effluents discharged into fresh and saline waters presents difficulties, especially in estuaries. The main difficulty is caused by the dissolved constituents being used to monitor the effluent also occurring naturally at similar levels. Uric acid is present at significant levels in untreated sewage and is not normally found in unpolluted waters. Until now no suitable routine method has been available for uric acid estimation in fresh and saline waters at levels normally encountered in the environment. In this paper we describe a recently developed technique using high-performance liquid chromatography which estimates uric acid in both fresh and saline waters in the range 1–10,000 μg l⁻¹ with a precision (2σ) of ±20% at 2 μg l⁻¹, ±4% at 40 μg l⁻¹ and ±2% at 10 mg l⁻¹.     

The toxicity of chlorine to a common vascular aquatic plant

Myriophyllum spicatum was exposed to various chlorine concentrations on a continuous and intermittent basis in 96-h toxicity studies utilizing a proportional diluter. Continuous exposure to chlorine concentrations as low as 0.05 mg l⁻¹ total residual chlorine (TRC) depressed shoot and total plant dry weights approx. 30% relative to controls. Shoot length was depressed approx. 16% at this concentration. Chlorophyll a was depressed 25% at 0.1 mg l⁻¹ TRC. However, intermittent exposure of plants to chlorine for three 2-h periods daily for 96 h indicated an insensitivity to repeated short term chlorine exposure at all concentrations but 1.0 mg l⁻¹ TRC. These results indicate that high level chlorine discharges from waste water facilities and electric generating plants could be a contributing factor impacting nearby submerged aquatic vegetation.     

The relationship between dissimilatory nitrate reduction and oxygen uptake by cells of an Alcaligenes strain in flocs and in suspension and by activated sludge flocs

The oxygen uptake and the dissimilatory nitrate reduction by anaerobically grown cells of a denitrifying Alcaligenes strain, occurring in floc form or in suspension, were studied at different oxygen concentrations in the surrounding medium. When the oxygen concentration in the medium fell below 1·5 mg l⁻¹, the nitrate reduction by the cells within flocs increased considerably. The cells in suspension showed an increased nitrate reduction when the oxygen concentration was below 0·1 mg l⁻¹. When anaerobically grown cells had been aerated for 24 h in a nitrogen-free medium, the cells became sensitive to respiration inhibition by nitric oxide, resulting from nitrate reduction. This gave rise to an increased nitrate reduction below 2·5 mg oxygen l⁻¹ when the cells were aggregated in flocs and below 0·1 mg oxygen per litre when the cells were in suspension. The nitrate reduction by the denitrifying, floc-forming pure culture was compared with that of activated sludge flocs.     

Comparative toxicity of ten organic chemicals to ten common aquatic species

The susceptibilities of 10 aquatic organisms to 10 organic chemicals were determined using lethality tests. The species included six fishes, two crustaceans, a chironomid and an amphibian. The chemicals were selected to span the toxicity range from 26 g l⁻¹ to 1 μg l⁻¹ and include chemicals which were lethal by four modes of toxic action. There was no consistent relative susceptibility among the test species because the sensitivity to specific modes of toxic action varied among the chemicals. Nonetheless, the toxicities of the chemicals to any given species were highly correlated to the toxicities to other species, particularly among fishes. The 96-h median lethal concentration (LC₅₀) of the chemicals to rainbow trout (Salmo gairdneri) could be estimated from the 96-h LC₅₀ with fathead minnows (Pimephales promelas) with a correlation coefficient greater than 0.99. Equations for estimating the lethal concentration of chemicals with each species from the 96-h LC₅₀ for fathead minnows are presented.     

Toxicity of silver to rainbow trout (Salmo gairdneri)

The mean 96-h LC₅₀'s of silver with rainbow trout were 6.5 μg l⁻¹ and 13.0 μg l⁻¹ in soft water (approximately 26 mg l⁻¹ hardness as CaCO₃) and hard water (350 mg l⁻¹ hardness as CaCO₃), respectively. The long-term, “no effect” concentration for silver, added to the water as silver nitrate, was between 0.09 and 0.17 μg l⁻¹ after 18 months exposure in soft water. The “no effect” concentration is that concentration range which defines no observed effect. Based on mortalities different from the control, no mortalities attributable to silver occurred at 0.09 μg Ag l⁻¹, whereas 17.2% mortality occurred to fish exposed to 0.17 μg ll⁻¹. The “no effect” concentration does not reflect possible effects of silver on spawning behavior or reproduction, since female rainbow trout will not generally reach sexual maturity before 3 yr. At silver concentrations of 0.17 μg l⁻¹ or greater, silver caused premature hatching of eggs and reduced growth rate in fry. In one experiment, the eggs were completely hatched within 10 days of exposure; whereas, control eggs completed hatching after 42 days. The prematurely erupted fry were not well developed and frequently died. The growth rate of surviving fry was greatly reduced.