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2.
Zinc bioavailability to aquatic organisms varies greatly under different pH values. In the present study, five native species in China and four common international test species were selected to investigate the influence of changing pH on acute zinc toxicity. The results showed that the higher trophic levels exhibited increasing sensitivity to zinc as pH decreased. However, when the pH value was between 8 and 11, the acute toxicity of zinc was relatively constant. In addition, by using a species-sensitivity distribution (SSD) method, the short-term hazardous concentrations of zinc at different pH values (based on the 5th percentiles of the pH-specific SSDs) were determined to be 17.26 µg/L (pH 4), 48.31 µg/L (pH 5), 80.34 µg/L (pH 6) and 230.6 µg/L (pH 7), respectively. The present study provides useful information for deriving water quality criteria and assessing the risks of metals in the near future. 相似文献
3.
Acute toxicity of 4-nonylphenol (NP) was examined in six freshwater species from three phyla – platyhelminthes, arthropoda
and mollusca. Values of the 48-hour LC 50 of NP for six species ranged from 20 to 508 ug/L and values of the 96-hour LC 50 for four species ranged from 120 to 457 ug/L. The most sensitive species tested was a water flea, Ceriodaphnia cornuta, with a 48-hour LC 50 of 20 μg/L. The no observed adverse effect level (NOAEL) and lowest observed adverse effect level (LOAEL) values of NP found
were in the range of <10 to 400 μg/L and 10 to 450 μg/L after 48 hours of exposure, respectively. 相似文献
6.
In tests of acute aquatic toxicity, the effects of protolyzing substances varies with pH. The Microtox toxicity of six chlorophenols was studied over a pH interval and the relation of effects to dissociation was examined. The p Ka values of the chlorophenols under the optimal test conditions are presented. The results of the Microtox toxicity tests supported a simple model of two species, phenol and phenate, with different specific toxicity. In five of the six chlorophenols only the effects of the phenol form were observed. The toxicity of the phenol form was 20 times or more higher than that of the phenate. 相似文献
7.
Assessment of contaminant impacts to federally identified endangered, threatened and candidate, and state-identified endangered species (collectively referred to as listed species) requires understanding of a species sensitivities to particular chemicals. The most direct approach would be to determine the sensitivity of a listed species to a particular contaminant or perturbation. An indirect approach for aquatic species would be application of toxicity data obtained from standard test procedures and species commonly used in laboratory toxicity tests. Common test species (fathead minnow, Pimephales promelas; sheepshead minnow, Cyprinodon variegatus; and rainbow trout, Oncorhynchus mykiss) and 17 listed or closely related species were tested in acute 96-hour water exposures with five chemicals (carbaryl, copper, 4-nonylphenol, pentachlorophenol, and permethrin) representing a broad range of toxic modes of action. No single species was the most sensitive to all chemicals. For the three standard test species evaluated, the rainbow trout was more sensitive than either the fathead minnow or sheepshead minnow and was equal to or more sensitive than listed and related species 81% of the time. To estimate an LC50 for a listed species, a factor of 0.63 can be applied to the geometric mean LC50 of rainbow trout toxicity data, and more conservative factors can be determined using variance estimates (0.46 based on 1 SD of the mean and 0.33 based on 2 SD of the mean). Additionally, a low- or no-acute effect concentration can be estimated by multiplying the respective LC50 by a factor of approximately 0.56, which supports the United States Environmental Protection Agency approach of multiplying the final acute value by 0.5 (division by 2). When captive or locally abundant populations of listed fish are available, consideration should be given to direct testing. When direct toxicity testing cannot be performed, approaches for developing protective measures using common test species toxicity data are available. 相似文献
8.
This study investigated the capacities of five species of aquatic bryophytes to accumulate As and Hg from their natural habitats in rivers in Galicia (NW Spain). The distributions of the concentrations of both elements in all species were skewed to the right, with a higher incidence of extreme values in the As data, which may indicate a greater degree of contamination by this metalloid. There were no significant differences in the accumulation of either of the elements between the different species studied, which justifies their combined use as biomonitors of As and Hg, at least in the study area. 相似文献
9.
Assessment of risk posed by an environmental contaminant to an aquatic community requires estimation of both its magnitude
of occurrence ( exposure) and its ability to cause harm ( effects). Our ability to estimate effects is often hindered by limited toxicological information. As a result, resource managers and environmental regulators are often
faced with the need to extrapolate across taxonomic groups in order to protect the more sensitive members of the aquatic community.
The goals of this effort were to 1) compile and organize an extensive body of acute toxicity data, 2) characterize the distribution
of toxicant sensitivity across taxa and species, and 3) evaluate the utility of toxicity extrapolation methods based upon
sensitivity relations among species and chemicals. Although the analysis encompassed a wide range of toxicants and species,
pesticides and freshwater fish and invertebrates were emphasized as a reflection of available data. Although it is obviously
desirable to have high-quality acute toxicity values for as many species as possible, the results of this effort allow for
better use of available information for predicting the sensitivity of untested species to environmental contaminants. A software
program entitled “Ecological Risk Analysis” (ERA) was developed that predicts toxicity values for sensitive members of the
aquatic community using species sensitivity distributions. Of several methods evaluated, the ERA program used with minimum
data sets comprising acute toxicity values for rainbow trout, bluegill, daphnia, and mysids provided the most satisfactory
predictions with the least amount of data. However, if predictions must be made using data for a single species, the most
satisfactory results were obtained with extrapolation factors developed for rainbow trout (0.412), bluegill (0.331), or scud
(0.041). Although many specific exceptions occur, our results also support the conventional wisdom that invertebrates are
generally more sensitive to contaminants than fish are. 相似文献
10.
HSAS (high-solubility alkyl sulfate) is a new anionic surfactant composed predominantly of methyl and ethyl branched hexadecyl
and heptadecyl sulfate. Effects of HSAS on a wide range of fish, algae, and invertebrates were investigated in conventional
laboratory toxicity tests as well as in exposures conducted as part of an experimental stream model ecosystem study. For invertebrates
and fish, C 16.7HSAS (average alkyl chain length 16.7) acute LC 50 values ranged from 0.23 (channel catfish) to 2.9 (Asiatic clam, Corbicula) mg/L in well and river waters. LC 50 values for those species tested in both waters were typically within a factor of 1.5 and all were within a factor of 2 of
each other, suggesting bioavailability is similar in these waters. Chronic toxicity values ranged from 0.070 (fathead minnow)
to 0.42 (amphipod, Hyalella) mg/L across fish and invertebrates with algal chronic toxicity values ranging from 0.5 (blue-green algae, Anabaena flos-aquae) to 7.8 (green algae, Scenedesmus) mg/L. The order of sensitivity to HSAS acute and chronic toxicity was fish = invertebrate > algae. Based on the chronic
single species sensitivity distribution, the concentrations protective of 90 and 95% of species were estimated to be 0.058
and 0.036 mg/L, respectively. These compare well with the model ecosystem NOEC of 0.064 mg/L (Belanger et al. 2005). 相似文献
11.
The acute effects of both untreated and dispersant-treated Prudhoe Bay crude oil on the early life-stages of three marine
species were investigated. Identification of which water-accommodated fraction (undispersed or chemically dispersed) was considered
“more toxic” was dependent on species, time, and endpoint (and by inference, test protocol). Generally, the data showed that
at roughly equivalent hydrocarbon concentrations untreated oil solutions resulted in higher initial effects (< 1 h) in mysid
and topsmelt tests, whereas dispersed oil solutions elicited higher levels of larval abnormality in abalone tests and higher
levels of mortality in mysid tests. While differences in test protocols existed among the species tested, topsmelt were the
most sensitive species to untreated oil solutions, with mysids being most sensitive to dispersed oil solutions.
Received: 1 February 1997/Accepted: 12 June 1997 相似文献
12.
Adult New Zealand freshwater mussel Echyridella menziesii were collected from three locations in the North Island of New Zealand. In a series of tests that followed standard test guidance, glochidia were exposed to either dissolved copper (Cu), zinc (Zn), or total ammonia nitrogen (TAN) for 6, 24, or 48 h (20 °C, pH 7.8, water hardness 30 mg L ?1 as CaCO 3, dissolved organic carbon [DOC] 2.0–2.9 mg L ?1). Of the three contaminants and tests that met control survival criteria, mussel larvae (glochidia) were most sensitive to Cu exposure (48-h EC 50 = 1.7–3.4 μg L ?1, 48-h no observed effect concentrations (NOEC) of 1.3–2.6 μg L ?1). The Zn 48-h EC 50 concentrations were 229–337 μg L ?1 and the 48-h NOEC values were 128–240 μg L ?1. Compared with other native New Zealand species, glochidia were also relatively sensitive to TAN exposure (48-h EC 50 12–15 mg TAN L ?1 [pH 7.8], 48-h NOEC 8–10 mg TAN L ?1). Comparison of our data with those of previous studies on North American freshwater mussels indicates that (1) E. menziesii are among those aquatic species most sensitive to acute Cu or TAN exposure; and (2) E. menziesii juveniles would not be adequately protected by current ANZECC water quality guidelines for TAN or Cu. Inclusion of North American juvenile mussel data in a revision of the current ANZECC water-quality guideline (95th percentile) for chronic ammonia exposure results in a decrease from 0.9 mg to 0.2 mg TAN L ?1 (pH 8). 相似文献
13.
Endosulfan sulfate is a persistent environmental metabolite of endosulfan, an organochlorine insecticide–acaricide presently
registered by the United States Environmental Protection Agency. There is, however, limited acute fish toxicity data for endosulfan
sulfate. This study determines the acute toxicity (LC 50s and LC 10s) of endosulfan sulfate to three inland Florida native fish species (mosquitofish [ Gambusia affinis]; least killifish [ Heterandria formosa]; and sailfin mollies [ Poecilia latipinna]) as well as fathead minnows ( Pimephales promelas) . Ninety-six-h acute toxicity tests were conducted with each fish species under flow-through conditions. For all of the above-mentioned
fish species, 96-h LC 50 estimates ranged from 2.1 to 3.5 μg/L endosulfan sulfate. The 96-h LC 10 estimates ranged from 0.8 to 2.1 μg/L endosulfan sulfate. Of all of the fish tested, the least killifish appeared to be the
most sensitive to endosulfan sulfate exposure. The above-mentioned data were combined with previous acute toxicity data for
endosulfan sulfate and freshwater fish for an effects analysis. The effects analysis estimated hazardous concentrations expected
to exceed 5, 10, and 50% of the fish species’ acute LC 50 or LC 10 values (HC 5, HC 10, and HC 50). The endosulfan sulfate freshwater-fish acute tests were also compared with the available freshwater-fish acute toxicity
data for technical endosulfan. Technical endosulfan is a mixture of α- and β-endosulfan. The LC 50s had a wider range for technical endosulfan, and their distribution produced a lower HC 10 than for endosulfan sulfate. The number of freshwater-fish LC 50s for endosulfan sulfate is much smaller than the number available for technical endosulfan, reflecting priorities in examining
the toxicity of the parent compounds of pesticides. The toxicity test results and effects analyses provided acute effect values
for endosulfan sulfate and freshwater fish that might be applied in future screening level ecologic risk assessments. The
effects analyses also discussed several deficiencies in conventional methods for setting water-quality criteria and determining
ecologic effects from acute toxicity tests. 相似文献
14.
The changes in the acute toxicity of 16 phenols toward Selenastrum capricornutum and Daphnia magna were examined as a function of their physical/chemical properties. The results demonstrated that phenols with a higher octanol-water
partition coefficient (K ow) had a higher toxicity toward aquatic organisms. The toxicity of phenols was closely related to the log K ow values, with correlation coefficients of 0.93 (except for the nitrophenols) and 0.89 for S. capricornutum and D. magna, respectively. The changes in the phenols toxicities in the site waters ( i.e., stream and effluent waters) were investigated by calculating the water effect ratios (WER) from the results of the toxicity
tests in the site waters using D. magna. The results showed that the degree of ionization for each phenolic compound was altered by the differences in the dissociation
constant (pK a), and the change in the toxicity could be predicted. Therefore, the WER should be considered when the toxicity of phenolic
compounds is estimated in site waters. The quantitative structure-activity relationships (QSAR) study showed that the toxicity
of the phenols to D. magna could be predicted by the hydrophobicity (log K ow) alone and by combining the log K ow with pK a, while the toxicity to S. capricornutum was predicted by a combination of hydrophobicity (log K ow) and E LUMO (or pK a). 相似文献
19.
No abstract available. 相似文献
20.
The acute toxicity of technical-grade glyphosate acid, glyphosate isopropylamine, and three glyphosate formulations was
determined for adults of one species and tadpoles of four species of southwestern Australian frogs in 48-h static/renewal
tests. The 48-h LC 50 values for Roundup? Herbicide (MON 2139) tested against tadpoles of Crinia insignifera, Heleioporus eyrei, Limnodynastes dorsalis, and Litoria moorei ranged between 8.1 and 32.2 mg/L (2.9 and 11.6 mg/L glyphosate acid equivalent [AE]), while the 48-h LC 50 values for Roundup? Herbicide tested against adult and newly metamorphosed C. insignifera ranged from 137–144 mg/L (49.4–51.8 mg/L AE). Touchdown? Herbicide (4 LC-E) tested against tadpoles of C. insignifera, H. eyrei, L. dorsalis, and L. moorei was slightly less toxic than Roundup? with 48-h LC 50 values ranging between 27.3 and 48.7 mg/L (9.0 and 16.1 mg/L AE). Roundup? Biactive (MON 77920) was practically nontoxic
to tadpoles of the same four species producing 48-h LC 50 values of 911 mg/L (328 mg/L AE) for L. moorei and >1,000 mg/L (>360mg/L AE) for C. insignifera, H. eyrei, and L. dorsalis. Glyphosate isopropylamine was practically nontoxic, producing no mortality among tadpoles of any of the four species over
48 h, at concentrations between 503 and 684 mg/L (343 and 466 mg/L AE). The toxicity of technical-grade glyphosate acid (48-h
LC 50, 81.2–121 mg/L) is likely to be due to acid intolerance. Slight differences in species sensitivity were evident, with L. moorei tadpoles showing greater sensitivity than tadpoles of the other four species. Adult and newly emergent metamorphs were less
sensitive than tadpoles.
Received: 19 February 1998/Accepted: 16 August 1998 相似文献
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