| 생태독성 발췌 | /AQUATIC SPECIES/ The acute and chronic toxicity of sulfate (tested as sodium sulfate) was determined in diluted well water (hardness of 100 mg/L and pH 8.2) with a cladoceran (Ceriodaphnia dubia2-day and 7-day exposures), a midge (Chironomus dilutus4-day and 41-day exposures), a unionid mussel (pink mucket, Lampsilis abrupta4-day and 28-day exposures), and a fish (fathead minnow, Pimephales promelas4-day and 34-day exposures). Among the 4 species, the cladoceran and mussel were acutely more sensitive to sulfate than the midge and fathead minnow, whereas the fathead minnow was chronically more sensitive than the other 3 species. Acute-to-chronic ratios ranged from 2.34 to 5.68 for the 3 invertebrates but were as high as 12.69 for the fish. The fathead minnow was highly sensitive to sulfate during the transitional period from embryo development to hatching in the diluted well water, and thus, additional short-term (7- to 14-day) sulfate toxicity tests were conducted starting with embryonic fathead minnow in test waters with different ionic compositions at a water hardness of 100 mg/L. Increasing chloride in test water from 10 mg Cl/L to 25 mg Cl/L did not influence sulfate toxicity to the fish, whereas increasing potassium in test water from 1 mg K/L to 3 mg K/L substantially reduced the toxicity of sulfate. The results indicate that both acute and chronic sulfate toxicity data, and the influence of potassium on sulfate toxicity to fish embryos, need to be considered when environmental guidance values for sulfate are developed or refined./AQUATIC SPECIES/ The study of the microalgal growth kinetics is an indispensable tool in all fields of phycology. Knowing the optimal nutrient concentration is an important issue that will help to develop efficient growth systems for these microorganisms. Although nitrogen and phosphorus are well studied for this purpose, sulfur seems to be less investigated. Sulfate is a primary sulfur source used by microalgaemoreover, the concentration of this compound is increasing in freshwater systems due to pollution. The aim of this study was to investigate the effects of different sodium sulfate concentrations in the culture medium on growth and growth kinetics of the freshwater microalga Chlamydomonas moewusii. Production of biomass, chl content, kinetic equations, and a mathematical model that describe the microalgal growth in relation with the concentration of sodium sulfate were obtained. The lowest concentration of sodium sulfate allowing optimal growth was 0.1 mM. Concentrations higher than 3 mM generated a toxic effect. This work demonstrates that this toxic effect was not directly due to the excess of sulfate ion but by the elevation of the ionic strength. An inhibition model was successfully used to simulate the relationship between specific growth rate and sodium sulfate in this microalga./AQUATIC SPECIES/ ...The hypothesis that if sodium sulfate alters the bioenergetics of Ceriodaphnia dubia, concentrations that cause reduced fecundity in the short (7-day) and long (5 generations) term should also cause changes in feeding rate and/or metabolism, measured as oxygen consumption /was tested/. In addition, ...the acute toxicity of phenol to C. dubia in the presence and absence of both food and sodium sulfate /was tested/. Sodium sulfate reduced the filter-feeding rate of C. dubia, which was associated with significantly reduced oxygen consumption. This decreased energy level appeared to result in a consistent but decreased level of fecundity over a number of generations and the reproductive impairment was dose-dependent. These effects occurred at concentrations much lower than those at which acute (mortality) effects have been observed, a finding that may have regulatory implications. In addition, whereas phenol toxicity to C. dubia was exacerbated by the addition of food, increased phenol toxicity, likely induced by an increase in filtering or metabolic rate due to food addition, was negated when sodium sulfate was added to the test medium./AQUATIC SPECIES/ Previous studies have documented reduced growth of clams downstream of sulfate-dominated effluents, altered bioenergetics in filter-feeding invertebrates, and interactions between sulfate and other toxicants. Therefore, the purpose of this study was to determine if sodium sulfate affects the bioenergetics of the filter-feeding, freshwater bivalve, Corbicula fluminea, and the mechanism by which the effects are elicited. In addition to measuring effects on feeding, respiration and growth rates, I evaluated the relative sensitivity of a green algae consumed by clams to determine if top-down or bottom-up effects might be exhibited under field conditions. This study demonstrated that sodium sulfate had no effect on basal metabolic rates, but significantly reduced the feeding, post-feeding metabolic, and growth rates of C. fluminea. The proposed mechanism for these impacts is that filtering rates are reduced upon exposure, resulting in reduced food consumption and therefore, preventing increased metabolic rates normally associated with post-feeding specific dynamic action (SDA). In the field, these effects may cause changes in whole stream respiration rates and organic matter dynamics, as well as alter uptake rates of other food-associated contaminants like selenium, the toxicity of which is known to be antagonized by sulfate, in filter-feeding bivalves.For more Ecotoxicity Excerpts (Complete) data for Sodium sulfate (10 total), please visit the HSDB record page. |
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