Toxic effects of an anionic detergent on the gills of rainbow trout

The changes that occur in the gill tissue of rainbow trout exposed to 100 mg l⁻¹ sodium lauryl sulphate are typical of an acute inflammatory reaction and are in general similar to the changes induced in gills by other toxic agents. The gill epithelium lifts away from the underlying tissue, and lymphocytes and granulocytes invade the subepithelial spaces. Large numbers of epithelial cells die and are sloughed off, but puncture of the epithelium does not occur. Detailed changes at the cellular level, mostly related to cell death, distinguish SLS-induced damage from that caused by zinc sulphate. Epithelial lifting may be a consequence of a decrease in gill surface area imposed by the need to maintain osmotic stability while sustaining the progressive loss of epithelial cells caused by pollutant action.     

The availability of cadmium to perfused rainbow trout gills in different water qualities

The uptake of cadmium in perfused gills from rainbow trout (Salmo gairdneri, Rich.) in different water qualities has been studied.In the naturally hard alkaline Uppsala tap water, the calcium concentration was the dominating factor controlling the cadmium transfer through the gills. A strong inverse relationship was measured between the external Ca²⁺ concentration up to 3 mmol l^?1 (< 120 mg Ca²⁺ l^?1), and the Cd transfer. A higher Ca²⁺ concentration (10 mmol l^?1) did not further affect the transfer. Magnesium decreased the transfer, but only at concentrations 4 to 5 times as high as calcium. At a constant Ca²⁺/Mg²⁺ hardness, the transfer was a function of the free cadmium ion activity (Cd²⁺). Ca²⁺ and Mg²⁺ selectively reduced the transfer by a biological mechanism, probably by changing the permeability of the gill epithelium.Cd transfer was not dependent on pH in the range pH 5–7. A lower transfer at pH 7.6 was related to a lower Cd²⁺ activity, probably due to the formation of non-available bicarbonate/carbonate complexes.Cd transfer decreased in the presence of 121 mmol l^?1 NaCl (0.7% salinity). This decrease was not caused by the altered osmotic gradient over the gills. The transfer was proportional to the Cd²⁺ activity. CdCl⁺ and CdCl₂ were not available for the gills.The retention of Cd in perfused gill tissue was proportional to the Cd²⁺ activity in all water qualities tested. Tissue accumulation of Cd was not sensitive to external Ca and Mg and in this respect different from the transfer.     

Assessing the impact of waterborne and dietborne cadmium toxicity on susceptibility risk for rainbow trout

The purpose of this study was to use a risk-based integrated-scale toxicological model to examine the impact of waterborne and dietborne cadmium (Cd) toxicity on rainbow trout (Oncorhynchus mykiss) susceptibility appraised with recent published data. A probabilistic assessment model was performed to estimate Cd susceptibility risk. The dose-response models were constructed based on two endpoints of % Cd in metabolically active pool (MAP) and susceptibility time that causes 50% effect (ST50). We further constructed an elimination-detoxification-recovery scheme to enhance the model predictive ability. We found a 95% probability of % Cd in gill and liver MAP exceeding 47-49% and it was likely (70% probability) to have exceeded 52-55%, but it was unlikely (30% probability) to have exceeded 56-60%. In contrast to gill and liver, gut had a relative lower Cd susceptibility risk (15-17% Cd in MAP) with a longer ST50. We suggested that the proposed probabilistic risk assessment framework can incorporate the elimination-detoxification-recovery scheme to help government based biomonitoring and bioassessment programs to prevent potential aquatic ecosystems and human health consequences.     

An investigation into the long-term effects of rhine water on rainbow trout

Rainbow trout were maintained in Rhine water for a period of 18 months in order to determine the chronic toxicological quality of this water. An equal number of trout were kept in ground water of drinking water quality under identical experimental conditions.Compared to this control group, the rainbow trout in Rhine water showed growth inhibition, enlarged liver and kidneys, reduced hemoglobin content, increased blood glucose level and a significant accumulation of chlorinated hydrocarbons in adipose tissue. Moreover, histological changes were observed in the liver and spleen at the end of the experiment.The effects mentioned are of a nature and extent such that it may be concluded that Rhine water is chronically toxic to rainbow trout.     

Monitoring of lead, cadmium, chromium and nickel in placenta from an e-waste recycling town in China

Toxic heavy metals are released to the environment constantly from unregulated electronic waste (e-waste) recycling in Guiyu, China, and thus may contribute to the elevation of lead and other heavy metals levels in placenta. We aimed to investigate concentrations of heavy metals, including lead (Pb), cadmium (Cd), chromium (Cr), and nickel (Ni) in placenta from Guiyu and compared them with those from a control area where no e-waste processing occurs. Two hundred and twenty human placentas were collected from Guiyu (n = 101) and the control area (n = 119). The placenta concentrations of Pb, Cd, Cr, and Ni (PCPb, PCCd, PCCr, and PCNi) were determined by graphite furnace atomic absorption spectrometry (GFAAS). Risk factors of high exposure and correlation with adverse pregnancy outcomes were analyzed using Spearman correlation analyses. PCPb from Guiyu ranged from 6.51 to 3465.16 ng/g with a median of 301.43 ng/g, whereas PCPb from the control area ranged from 4.53 to 3176.12 ng/g with a median of 165.82 ng/g (P = 0.010). We also observed that in Guiyu, 41.6% of women (42/101) had PCPb > 500 ng/g wt (wet weight), compared with 24.4% of women (29/119) in the control area (P = 0.006). No significant differences of PCCd and PCCr were found between the two groups. In contrast, PCNi was higher in samples from the control area (median 14.30, range 1.76-593.70 ng/g) than in Guiyu samples (median 7.64, range 1.19-1108.99 ng/g) (P = 0.000), and a negative correlation between PCNi and gestational age was found in this study (P = 0.017). Spearman correlation analyses showed that there was correlation between PCPb and residence in e-waste recycling area. Environmental pollution, resulted from unregulated e-waste recycling activities, may contribute to elevated PCPb in neonates born in Guiyu and threaten their health.     

Biomonitorization of cadmium, chromium, manganese, nickel and lead in whole blood, urine, axillary hair and saliva in an occupationally exposed population

Heavy metal contamination from occupational origin is a cause for concern because of its potential accumulation in the environment and in living organisms leading to long term toxic effects. This study was aimed to assess Cd, Cr, Mn, Ni and Pb levels in whole blood, urine, axillary hair and saliva from 178 individuals with occupational exposure to heavy metals. Levels of metal compounds were determined by atomic absorption spectrometry. We collected information on occupation, lifestyle habits and food intake by questionnaire. Multiple linear regression analyses for metal ion concentration in whole blood, urine, axillary hair and saliva were adjusted for age, gender, smoking and alcohol consumption, lifetime workplace exposure, residence area and food habits. Overall, blood and urine median concentrations found for the five metals analyzed do not exceed biological exposure indexes, so that they are very similar to a non-occupationally exposed population. Toxicokinetic differences may account for the lack of correlations found for metal levels in hair and saliva with those in blood or urine. For those heavy metals showing higher median levels in blood with respect to hair (Cd, Mn and Pb) indicating lesser hair incorporation from blood, the lifetime working experience was inversely correlated with their hair levels. The longer the lifetime working experience in industrial environments, the higher the Mn and Ni concentration in saliva. Axillary hair and saliva may be used as additional and/or alternative samples to blood or urine for biomonitoring hair Mn, and saliva Ni in subjects with occupational exposure.     

Acute lethality, and sub-lethal effects of acetone, ethanol, and propylene glycol on the cardiovascular and respiratory systems of rainbow trout Salmo gairdneri

Acute lethality and sub-lethal effects of acetone, ethanol, and propylene glycol on the cardiovascular and respiratory systems of rainbow trout (Salmo gairdneri) were examined. The 24 h LC₅₀ values for acetone and ethanol in a flow-through bioassay system at 10°C ± 0.5, are 6100 mg l⁻² and 11,200 mg l⁻¹, respectively. No mortality to fingerling trout was produced by propylene glycol at 50,000 mg l ⁻¹ during a 24 h exposure period in a static system.Acetone and ethanol, at about 0.48 and 0.26 of the fingerling LC₅₀, respectively, affected cardiovascular/respiratory parameters in adult rainbow trout. Acetone produced an increase in ventilation rate to a maximum of 158% of control values, as well as an increase in buccal pressure amplitude attaining a maximum of 410% of control values. Ethanol exposed fish exhibited a slight depression in ventilation rate and buccal pressure amplitude during initial stages of the 24 h exposure period. Ethanol had no effect on heart rate, despite a significant decrease in Q-T interval. Propylene glycol, at less than 0.08 of a concentration not producing apparent stress in fingerlings, had a mildly stimulatory effect on ventilation rate, and heart rate in adults. It is concluded that of the three solvents employed in this study, propylene glycol is most suitable for use as a solvent in fish toxicity tests.     

Quantities and associations of lead, zinc, cadmium, manganese, chromium, nickel, vanadium, and copper in fresh Mississippi delta alluvium and New Orleans alluvial soils

The topic of this study is the effect of anthropogenic metals on the geochemical quality of urban soils. This is accomplished by comparing the metal contents and associations between two alluvial soils of the lower Mississippi River Delta, freshly deposited alluvial parent materials and alluvial soils collected from a nearby urban environment. Fresh alluvium samples (n = 97) were collected from the Bonnet Carré Spillway. The urban alluvial soil samples (n = 4026) were collected from New Orleans and stratified by census tracts (n = 286). The Spillway samples tend to have less Pb and Zn than generally noted for the baseline of natural soils. Except for Mn and V, Spillway alluvium contains significantly less metal than urban soils. For Spillway samples, the median metal content (in microg g(-1)) is 4.7 Pb, 11.1 Zn, 0.7 Cd, 164 Mn, 0.8 Cr, 3.9 Ni, 3.2 V, and 3.9 Cu. For urban soils, the median metal content (in microg g(-1)) is 120 Pb, 130 Zn, 3.2 Cd, 138 Mn, 2.1 Cr, 9.8 Ni, 3.8 V, and 12.7 Cu. Metal associations also differ between Spillway alluvium and urban alluvial soils. Fresh alluvium correlation coefficients between individual metals vary from 0.87 to 0.99 (P < 10(-13)) except for Cr which ranges from 0.57 to 0.68 (P < 10(-7)). The urban soil correlation coefficients for metals and the index value are 0.40-0.98. In urban soils, Pb, Zn, Cr, and Cu are dominant metals and highly associated, with a correlation coefficient ranging from 0.83 to 0.98 (P < 10(-25)). Their strong association justifies the use of GIS to map the integrated soil metal index (sum of the medians of metals by census tract) of New Orleans. Although also positively correlated (0.40-0.68, P < 10(-10)), Cd, Mn, Ni and V differ in their distribution in the city compared to Pb, Zn, Cr and Cu. Overall, significantly higher metal values occur in the inner city and lower values occur in outlying areas. The human health impact of the mixture of metals is not well understood. This study provides empirical data about the mixture and distribution of metals in New Orleans alluvial soils. Given common technical development, especially of traffic flows in cities, similar patterns of soil metals are expected for all US cities and probably international cities as well. Primary prevention of urban metal accumulations is necessary to enhance and sustain the development of urban culture.     

Effects of water hardness and pH on vanadium lethality to rainbow trout

Seven-day LC₅₀s of vanadium pentoxide for 2.5-g trout showed only a small range, from 1.9 to 6.0 mg V I⁻¹, in tests at all 12 combinations of 30, 100 and 355 mg 1⁻² total hardness with pH 5.5, 6.6, 7.7 and 8.8. Toxicity decreased from low to high hardness by an average factor of 1.8, probably because of regulated vanadium intake at the gill membranes. Hardness did not exert a major effect, probably because vanadium is present in water as various anions and does not complex with carbonates and bicarbonates as do most metals which behave as cations. Toxicity was greatest at pH 7.7, and the predominating ion H₂VO⁻₄ was apparently the most toxic one. HVO²⁻₄ which prevailed at high pH, was calculated to be 60% as toxic as H₂VO⁻₄. Toxicity decreased at pH 6.6 and 5.5, probably because much of the metal was then present as decavanadates, which were found to be half as toxic as H₂VO⁻₄ on the basis of vanadium content. Small fish were more resistant to vanadium than larger ones, at least up to 12 g wet wt. However cumulative mortality continued to increase until 2 weeks of exposure, and incipient lethal levels were probably much the same for fish of different size, at about 60–70% of the 7-d LC₅₀s stated in the paper. The toxicity of vanadium is similar to that of zinc except that it does not show a major change with water hardness.     

The effects of zinc on the cardiac and ventilatory rhythms of rainbow trout (Salmo Gairdneri, Richardson) and their responses to environmental hypoxia

Recordings were made of the cardiac and ventilatory rhythms of rainbow trout subjected to solutions of 40 and 10 ppm zinc in an experimental circulation. The higher concentration produces clearly-defined increases in ventilatory and coughing frequency and a decrease in heart rate; the percentage coupling between the two rhythms usually increased.

During exposure to 10 ppm added zinc the effects are not so readily discernible but are comparable in type. The addition of 10 ppm zinc has a significant effect on the responses of rainbow trout to hypoxia before and after this treatment.

It is concluded that zinc interferes with some of the mechanisms involved in the uptake of oxygen at the gills and consequently can significantly affect the ability of fish to respond to the additional stress of oxygen lack in its environment.     

Temperature effect on the elimination of pentachlorophenol,hexachlorobenzene and mirex by rainbow trout (salmo gairdneri)

The elimination rates of pentachlorophenol, hexachlorobenzene and mirex were estimated in rainbow trout that were held at 4, 12 and 18°C for 120 days following a single oral exposure. The results suggested temperature could become an important environmental variable in deriving a coefficient for the elimination component of a contaminant dynamics model. This response would be most applicable for those substances that are eliminated relatively rapidly, and those models that simulate the contaminant dynamics of fish in its natural environment.     

Effect of dissolved organic carbon on the mobility of cadmium, nickel and zinc in leachate polluted groundwater

The ability of dissolved organic carbon (DOC) from landfill leachate polluted groundwater to form complexes with the heavy metals cadmium (Cd), nickel (Ni) and zinc (Zn) was investigated. The DOC samples originated from the leachate pollution plume at Vejen Landfill, Denmark and were studied in the original matrix with a minimum of manipulation. The experiments were performed as batch sorption experiments and the metal distribution between the aquifer material and the solution (K_d) was determined in the leachate polluted groundwater samples and in reference solutions of synthetic inorganic leachate. The difference in distribution coefficients was a direct indication of complex formation between DOC and heavy metals. The results showed, that DOC from landfill leachate polluted groundwater has the ability to form complexes with Cd, Ni and Zn, and the distribution coefficients were a factor of 2–6 lower in the presence of DOC. Based on the distribution coefficients, the relative migration velocities of the heavy metals were estimated. The migration velocity of the metals was increased by the presence of DOC but did not exceed 1.2% of the water migration velocity, indicating that the effect of DOC on the mobility of Cd, Ni and Zn may have only minor environmental importance. Conditional complex formation constants (log K_c) were estimated from the K_d-values. The constants for 1:1 complexes increased slightly in the following order Zn < Cd < Ni. However, increasing the metal concentration into the mg l⁻¹ level decreased the constants by about one order of magnitude, showing the importance of determining the constants at environmentally relevant metal concentrations.     

Comparative short-term tolerance of zebrafish, flagfish, and rainbow trout to five poisons including potential reference toxicants

Zebrafish (Brachydanio rerio) and flagfish (Jordanella floridae) were evaluated as potential standard species for aquatic bioassays in Canada by comparing their short-term tolerance to that of rainbow trout (Salmo gairdneri). When threshold or 10-day LC₅₀'s for rainbow trout were assigned a value of 1.0, corresponding values for zebrafish and flagfish were respectively: copper sulfate, 1.6, 7.2; sodium pentachlorophenate, 4.7, 7.6; phenol, 2.5, 3.1; picloram, 1.6, 0.55; and dodecyl sodium sulfate, 2.8, 2.4. On the average, zebrafish were 2.6 times as tolerant as trout, and flagfish 4.2 times. Ratios of zebrafish/trout LC₅₀'s were considerably less variable than flagfish/trout LC₅₀'s. Considering the known variable response of rainbow trout and a maximum ratio of only 7.6 for exotic/trout LC₅₀'s, responses of zebrafish and flagfish were judged not sufficiently different from those of rainbow trout to discount either exotic species from further consideration as a potential standard test-fish.As a reference toxicant, sodium pentachlorophenate presented difficulties with analysis and availability. Dodecyl sodium sulfate showed no threshold of acute lethality for trout and 5-yr-old DSS had about one-third the toxicity of 1-year old DSS. Phenol met all criteria considered for a reference toxicant.     

Effects of copper, pH and hardness on the critical swimming performance of rainbow trout (Salmo gairdneri Richardson)

Critical swimming velocities of Salmo gairdneri at 12°C were determined in different combinations of copper; pH and hardness. Measurements were made after exposure for 0.5, 5, 10, and 30 days. When copper was not applied, hardness, pH and exposure time had no appreciable effect on critical performance. Copper had the greatest effect on swimming performance at 5 days of exposure. At pH 7.5–8.0, recovery from the initial depression was complete after 10 days of exposure, but critical swimming performance did not return to control levels in pH 6.0 treatments. For any given hardness, copper had a greater effect on critical speed at low than at high pH. A given copper treatment had a more pronounced effect at low than at high hardness.No distinction could be made among total, soluble, or extractable copper but predicted concentrations of 6 specific cupric ions varied with pH and hardness. Of these copper species, only Cu²⁺ and CuOH⁺ were found to be related significantly to critical performance.Oxygen consumption of trout was determined in different combinations of copper and pH. In the presence of copper the maximum oxygen consumption decreased and the energy expenditure for a given swimming speed increased.The above observations are discussed in relation to reported toxic actions of copper.     

The effect of arsenic on embrional development of rainbow trout (Salmo gairdneri, RICH.)

Studies were made on the toxic effect and accumulation of arsenic in developing eggs of rainbow trout. Fertile eggs were incubated at 6–7°C in sodium arsenate or arsenic trioxide solution at concentrations of 0.05–50.0 ppm As. The effect of arsenic on the survival of embryos and on the accumulation of the element in eggs were found to be related to the arsenic concentration and to the arsenic compound used (value of As-ion).     

Geochemical factors complicating the use of aufwuchs to monitor bioaccumulation of arsenic, cadmium, chromium, copper and zinc

Material accumulating on submerged glass slides was sampled from five sites associated with coal ash settling basins and a control site. Correlation analyses demonstrated a strong, positive correlation between the five elements, arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu) and zinc (Zn) and concentrations of associated iron or manganese. Negative, weak or nonsignificant correlations were noted between the concentrations of these five elements and microfloral cell densities or per cent ash free weight of the material. Scanning electron microscopy and X-ray analyses indicated that the majority of the material was abiotic and the elemental levels associated with the abiotic components were generally higher than those of the biotic components. Hydrous iron and manganese oxides likely play dominant roles in determining the trace element concentrations in these procedurally-defined aufwuchs. These findings indicate the potential for misinterpretation of biomonitoring data employing procedurally-defined aufwuchs.     

The effect of surfactants on the mixed chelate extraction-atomic absorption spectrophotometric determination of copper, nickel, iron, cobalt, cadmium, zinc and lead

Twelve surfactants representing pure cationic, anionic and non-ionic detergents, three commercial detergents, sodium pyrophosphate, sodium tripolyphosphate, a soap, nitrilotriacetic acid (NTA), EDTA, and humic acid were investigated for their effect on the extraction-atomic absorption spectrophotometric determination of copper, nickel, iron, cobalt, cadmium, zinc and lead. Cations were extracted into 10 ml of a solution containing diphenylthiocarbazone, 8-quinolinol and acetyl acetone in ethyl propionate. To avoid emulsion formation, the maximum concentration of linear alkylate sulphonate (LAS) was 10 mg l⁻¹ and for solid industrial LAS-type detergent was 50 mg l⁻¹, but washing powder did not interfere at 100 mg l⁻¹. Cationic and non-ionic detergents gave low recoveries for cobalt. Condensed phosphates at a concentration of 20 mg l⁻¹ did not cause significant interference. NTA interfered with nickel extraction and EDTA with all metals. Humic acid, however, gave no interference. A standard addition procedure can be used to correct the results.A comparison is made between the APDC-MIBK and the mixed chelate-ethyl propionate methods for the determination of trace metals in the presence of various surfactants in natural waters; the latter is preferable.