Bioluminescence inhibition assays for toxicity screening of wood extractives and biocides in paper mill process waters

The risk associated with wood extractives, biocides, and other additives in pulp and paper mill effluents was evaluated by performing a characterization of process waters and effluents in terms of toxicity and chemical analysis. The individual toxicity of 10 resin acids, two unsaturated fatty acids, and three biocides was estimated by measuring the bioluminescence inhibition with a ToxAlert 100 system. Median effective concentration values (EC50) of 4.3 to 17.9, 1.2 to 1.5, and 0.022 to 0.50 mg/L were obtained, respectively. Mixtures of these three families of compounds showed antagonistic effects. Chemical analysis of process waters was performed by liquid chromatography- and gas chromatography-mass spectrometry. Biocides such as 2-(thiocyanomethylthio)-benzotiazole (TCMTB) (EC50 = 0.022 mg/L) and 2,2-dibromo-3-nitrilpropionamide (DBNPA) (EC50 = 0.50 mg/L) were the most toxic compounds tested and were detected at concentrations of 16 and 59 microg/L, respectively, in a closed-circuit recycling paper mill. Process waters from kraft pulp mills, printing paper mills, and packing board paper mills showed the highest concentration of resin acids (up to 400 microg/L) and accounted for inhibition percentages up to 100%. Detergent degradation products such as nonylphenol (NP) and octylphenol (OP) and the plasticizer bisphenol A (BPA) were also detected in the waters at levels of 0.6 to 10.6, 0.3 to 1.4, and 0.7 to 187 microg/L, respectively. However, once these waters were biologically treated, the concentration of detected organic compounds diminished and the toxicity decreased in most cases to values of inhibition lower than 20%.     

Wastewater treatment polymers identified as the toxic component of a diamond mine effluent

The Ekati Diamond Mine, located approximately 300 km northeast of Yellowknife in Canada's Northwest Territories, uses mechanical crushing and washing processes to extract diamonds from kimberlite ore. The processing plant's effluent contains kimberlite ore particles (< or =0.5 mm), wastewater, and two wastewater treatment polymers, a cationic polydiallydimethylammonium chloride (DADMAC) polymer and an anionic sodium acrylate polyacrylamide (PAM) polymer. A series of acute (48-h) and chronic (7-d) toxicity tests determined the processed kimberlite effluent (PKE) was chronically, but not acutely, toxic to Ceriodaphnia dubia. Reproduction of C. dubia was inhibited significantly at concentrations as low as 12.5% PKE. Toxicity identification evaluations (TIE) were initiated to identify the toxic component of PKE. Ethylenediaminetetraacetic acid (EDTA), sodium thiosulfate, aeration, and solid phase extraction with C-18 manipulations failed to reduce PKE toxicity. Toxicity was reduced significantly by pH adjustments to pH 3 or 11 followed by filtration. Toxicity testing with C. dubia determined that the cationic DADMAC polymer had a 48-h median lethal concentration (LC50) of 0.32 mg/L and 7-d median effective concentration (EC50) of 0.014 mg/L. The anionic PAM polymer had a 48-h LC50 of 218 mg/L. A weight-of-evidence approach, using the data obtained from the TIE, the polymer toxicity experiments, the estimated concentration of the cationic polymer in the kimberlite effluent, and the behavior of kimberlite minerals in pH-adjusted solutions provided sufficient evidence to identify the cationic DADMAC polymer as the toxic component of the diamond mine PKE.     

Toxicity of mono- and diesters of o-phthalic esters to a crustacean, a green alga, and a bacterium

The degradation of phthalic acid diesters may lead to formation of o-phthalic acid and phthalic acid monoesters. The ecotoxic properties of the monoesters have never been systematically investigated, and concern has been raised that these degradation products may be more toxic than the diesters. Therefore, the aquatic toxicity of phthalic acid, six monoesters, and five diesters of o-phthalic acid was tested in three standardized toxicity tests using the bacteria Vibrio fischeri, the green algae Pseudokirchneriella subcapitata, and the crustacean Daphnia magna. The monoesters tested were monomethyl, monoethyl, monobutyl, monobenzyl, mono(2-ethylhexyl), and monodecyl phthalate, while the diesters tested were dimethyl, diethyl, dibutyl, butylbentyl, and di(2-ethylhexyl)phthalate, which were assumed to be below their water solubility. The median effective concentration (EC50) values for the three organisms ranged from 103 mg/L to >4.710 mg/L for phthalic acid, and corresponding values for the monoesters ranged from 2.3 mg/L (monodecyl phthalate in bacteria test) to 4,130 mg/L (monomethyl phthalate in bacteria test). Dimethyl and diethyl phthalate were found to be the least toxic of the diesters (EC50 26.2-377 mg/L), and the toxicity of the other diesters (butylbenzyl and dibutyl phthalate) ranged from 0.96 to 7.74 mg/L. In general, the phthalate monoesters (degradation products) were less toxic than the corresponding diesters (mother compounds).     

Toxicity of laundry detergent components to a freshwater cladoceran and their contribution to detergent toxicity

The toxicity of 39 laundry detergent components including surfactants, enzymes, builders, fabric brighteners, fillers, and coloring agents to the cladoceran Ceriodaphnia cf. dubia was determined. The difference between the most and the least toxic components was approximately 17,000-fold and 1,000,000-fold for the mg/L and mmol/L EC50 data, respectively. Two of the components had high toxicity (EC50 values < 1 mg/L), 11 moderate toxicity (EC50 values between 1 and 10 mg/L), and the remaining 26 components had low toxicity (EC50 values > 10 mg/L). Analysis revealed that mixtures of the components interacted antagonistically, additively, and synergistically. On a molarity basis the most toxic group of compounds was the surfactants followed by the brighteners. The most toxic individual components included sodium carboxymethyl cellulose, sodium silicate solution, four brighteners, sodium perborate tetrahydrate, and the surfactants. Many of the most toxic components, however, contributed very little to the toxicity of the detergents due to being present in the detergents at low concentrations. The main contributors to the toxicity of detergents were the sodium silicate solution and the surfactants-with the remainder of the components contributing very little to detergent toxicity. The potential for acute aquatic toxic effects due to the release of secondary or tertiary sewage effluents containing the breakdown products of laundry detergents may frequently be low. However, untreated or primary treated effluents containing detergents may pose a problem. Chronic and/or other sublethal effects that were not examined in this study may also pose a problem.     

Assessment of the toxicity of triasulfuron and its photoproducts using aquatic organisms

The toxicological effects of the sulfonylurea herbicide triasulfuron and its photoproducts were assessed on four aquatic organisms. Toxicity varied with tested organism and with triasulfuron irradiation time. Triasulfuron and its photoproducts had no significant effects on the crustacean (Cladocera) Daphnia magna (causing 50% effective concentration [EC50] [48 h] = 49 +/- 1 mg/L) and the marine bacteria Vibrio fischeri (EC50 [30 min] > 100 mg/L). In contrast, primary producers (the duckweed Lemna minor, the microalgae Pseudokirchneriella subcapitata, and Chlorella vulgaris) were very sensitive to triasulfuron (EC50s < 11 microg/L). For these organisms, triasulfuron photoproducts were less toxic than the parent compound but the residual toxicity observed still represented a potential environmental hazard.     

Ecotoxicity and genotoxicity assessment of cytostatic pharmaceuticals

The fate and effects of cytostatic (anticancer or antineoplastic) pharmaceuticals in the environment are largely unknown, but they can contaminate wastewater treatment effluents and consequently aquatic ecosystems. In this paper, we have focused on five cytostatic compounds used in high amounts (cyclophosphamide, cisplatin, 5-fluorouracil, doxorubicin, and etoposide), and we have investigated their ecotoxicity in bacterial Pseudomonas putida growth-inhibition test, algal Pseudokirchneriella subcapitata growth-inhibition test, and Dapnia magna acute immobilization test. Genotoxicity also was assessed with Escherichia coli SOS-chromotest (with and without metabolic activation) and the GreenScreen Assay using yeast S. cerevisiae. All tested compounds showed significant effects in most of the assays with lowest-observed-effect concentrations and concentrations causing 50% effects (EC50s) values ranging within microg/L to mg/L. The most toxic compound was 5-fluorouracil in the assays with P. putida (EC50 = 0.027 mg/L) and P. subcapitata (EC50 = 0.11 mg/L), although cisplatin and doxorubicin were the most toxic to D. magna (EC50 = 0.64 and 2.0 mg/L, respectively). These two chemicals were also the most genotoxic in the SOS-chromotest (minimum genotoxic concentrations [MGC] = 0.07-0.2 mg/L), and 5-fluorouracil was the most genotoxic in the eukaryotic yeast assay (MGC = 0.02 mg/L). Our investigation seems to indicate generally lower risks of acute effects at concentrations expected in the environment. However, some effective concentrations were relatively low and chronic toxicity of cytostatics (and/or their transformation products), as well as specific sources of human pharmaceuticals such as hospital effluents, require research attention.     

Use of Japanese Medaka (Oryzias latipes) and Tilapia (Oreochromis mossambicus) in Toxicity Tests on Different Industrial Effluents in Taiwan

In Taiwan, aquatic toxicity tests for industrial effluents are not required for discharge permits. However, relying on traditional chemical and physical characteristics of an effluent to monitor and regulate such discharges to manage water quality of a receiving water is insufficient. In this study, we used two fish species, Japanese medaka (Oryzias latipes) and tilapia (Oreochromis mossambicus), and three toxic endpoints, including acute and subacute toxicity, to determine toxicity of seven different types of industrial effluents. Prior to the study, two reference toxicants were tested on two fish species. The LC50s of CdCl₂ for tilapia and medaka juveniles were 29.6 ± 15.3 mg/L and 2.2 ± 1.2 mg/L, respectively. The sensitivity of medaka embryo mortality and hatching inhibition to CdCl₂ were about the same, with the LC50 and EC50 of 0.3 ± 0.1 mg/L and 0.1 ± 0.1 mg/L, respectively. The LC50s for tilapia and medaka juveniles to sodium dodecyl sulfate (SDS) were 19.7 ± 10.6 mg/L and 12.5 ± 5.9 mg/L. The medaka embryo was less sensitive to SDS than to CdCl₂. The embryo's LC50 for SDS was 5.8 ± 2.8 mg/L and the hatching inhibition EC50 was 1.3 ± 1.1 mg/L. Results of toxicity tests on different effluents showed that the electroplating effluent was the most toxic, followed by acrylonitrile manufacturing and pulp/paper mill discharges. The LC50s of the electroplating effluent to different assays were in the range of several percents of the whole effluent. The pulp/paper effluent was toxic only to the medaka embryo. The rest of the industrial effluents tested showed either moderate or no toxicity to the animals. Received: 12 June 2000/Accepted: 6 September 2000     

Acute and chronic toxicity of nickel to a cladoceran (Ceriodaphnia dubia) and an amphipod (Hyalella azteca)

This study evaluated acute and chronic nickel (Ni) toxicity to Ceriodaphnia dubia and Hyalella azteca with the objective of generating information for the development of a biotic ligand model for Ni. Testing with C. dubia was used to evaluate the effect of ambient hardness on Ni toxicity, whereas the larger H. azteca was used to derive lethal body burden information for Ni toxicity. As was expected, acute C. dubia median lethal concentrations (LC50s) for Ni increased with increasing water hardness. The 48-h LC50s were 81, 148, 261, and 400 microg/L at hardnesses of 50, 113, 161, and 253 mg/L (as CaCO3), respectively. Ceriodaphnia dubia was found to be significantly more sensitive in chronic exposures than other species tested (including other daphnids such as Daphnia magna); chronic toxicity was less dependent on hardness than was acute toxicity. Chronic 20% effective concentrations (EC20s) were estimated at <3.8, 4.7, 4.0, and 6.9 microg/L at hardnesses of 50, 113, 161, and 253 mg/L, respectively. Testing with H. azteca resulted in a 96-h LC50 of 3,045 microg/L and a 14-d EC20 of 61 microg/L at a hardness of 98 mg/L (as CaCO3). Survival was more sensitive than was growth in the chronic study with H. azteca. The 20% lethal accumulation effect level based on measured Ni body burdens was 247 nmol/g wet weight.     

Influence of dissolved organic carbon on toxicity of copper to a unionid mussel (Villosa iris) and a cladoceran (Ceriodaphnia dubia) in acute and chronic water exposures

Acute and chronic toxicity of copper (Cu) to a unionid mussel (Villosa iris) and a cladoceran (Ceriodaphnia dubia) were determined in water exposures at four concentrations of dissolved organic carbon (DOC; nominally 0.5, 2.5, 5, and 10 mg/L as carbon [C]). Test waters with DOC concentrations of 2.5 to 10 mg?C/L were prepared by mixing a concentrate of natural organic matter (Suwannee River, GA, USA) in diluted well water (hardness 100 mg/L as CaCO(3) , pH 8.3, DOC 0.5 mg C/L). Acute median effect concentrations (EC50s) for dissolved Cu increased approximately fivefold (15-72 μg Cu/L) for mussel survival in 4-d exposures and increased about 11-fold (25-267 μg Cu/L) for cladoceran survival in 2-d exposures across DOC concentrations from 0.5 to 10 mg?C/L. Similarly, chronic 20% effect concentrations (EC20s) for the mussel in 28-d exposures increased about fivefold (13-61 μg Cu/L for survival; 8.8-38 μg Cu/L for biomass), and the EC20s for the cladoceran in 7-d exposures increased approximately 17-fold (13-215 μg Cu/L) for survival or approximately fourfold (12-42 μg Cu/L) for reproduction across DOC concentrations from 0.5 to 10 mg?C/L. The acute and chronic values for the mussel were less than or approximately equal to the values for the cladoceran. Predictions from the biotic ligand model (BLM) used to derive the U.S. Environmental Protection Agency's ambient water quality criteria (AWQC) for Cu explained more than 90% of the variation in the acute and chronic endpoints for the two species, with the exception of the EC20 for cladoceran reproduction (only 46% of variation explained). The BLM-normalized acute EC50s and chronic EC20s for the mussel and BLM-normalized chronic EC20s for the cladoceran in waters with DOC concentrations of 2.5 to 10 mg?C/L were equal to or less than the final acute value and final chronic value in the BLM-based AWQC for Cu, respectively, indicating that the Cu AWQC might not adequately protect the mussel from acute and chronic exposure, and the cladoceran from chronic exposure.     

Ecological hazard assessment of major veterinary benzimidazoles: acute and chronic toxicities to aquatic microbes and invertebrates

Aquatic toxicities of six benzimidazole-based anthelmintics-namely, albendazole, thiabendazole, flubendazole, febantel, fenbendazole, and oxfendazole-were evaluated with a marine bacterium, Vibrio fischeri, and a freshwater invertebrate, Daphnia magna. Delayed and chronic toxicity tests using D. magna also were conducted for benzimidazoles with high acute toxicity. Vibrio fischeri was greater than 10-fold less sensitive to most of the benzimidazoles tested compared to daphnids. For D. magna, the most acutely toxic anthelmintic compound tested was fenbendazole (48-h median effective concentration [EC50s], 16.5 microg/L), followed by flubendazole (48-h EC50, 66.5 micro/L), albendazole (48-h EC50, 67.9 microg/L), febantel (48-h EC50, 216.5 microg/L), thiabendazole (48-h EC50, 843.6 microg/L), and oxfendazole (48-h EC50, 1,168.4 microg/L). The lipophilicity parameter, log Kow, explained the observed acute D. magna toxicity of the individual benzimidazoles (r = -0.91, p < 0.01). Delayed expression of toxicity observed for 21 d after 96-h exposure to fenbendazole and flubendazole was not notable, which might result from the relatively high elimination constants for the chemicals. With chronic exposure to fenbendazole, D. magna survival, reproduction, and growth were significantly impacted at 1.25 to 4.1 microg/L (p < 0.05). Hazard quotients estimated for fenbendazole, albendazole, flubendazole, and febantel were 2,770, 9.7, 4, and 1.2, respectively, suggesting a need for further investigation and a potential for environmental concerns, particularly with fenbendazole.     

Ecotoxicological evaluation of wastewater treatment plant effluent discharges: a case study in Prato (Tuscany, Italy)

Textile wastewaters, which contain numerous chemicals such as dyes, surfactants, solvents, organic and inorganic salts, can cause severe pollution problems for the receiving freshwaters. The ecotoxicity of wastewaters in Prato, where there are about 14,000 textile and related factories, was investigated from 1996-1999 by means of bioassays. 147 samples of reclaimed wastewater were collected at the outlets of 4 centralized wastewater treatment plants. The acute and chronic toxicity of the effluents was measured with bioassays using three different target organisms: green algae (Pseudokirchneriella subcapitata), crustaceans (Daphnia magna) and bioluminescent bacteria (Vibrio fischeri). Toxicity was expressed as Effective Concentration 50 (EC50) and Toxic Units (TU). The results indicated that the effluents did not have significant acute toxicity: only 2.74% (EC50<100%, TU>1) of the 146 samples tested with crustaceans and 6.52% (EC50<50%, TU>2) of the 78 tested with bioluminescent bacteria showed toxic effects. With algae, slight chronic toxicity was found in 49.33% (mean EC50 value=86.56%, mean TU=1.16) of the 140 samples tested. The highest relative response was found with the algal assay using Pseudokirchneriella subcapitata: 49.33% of 140 samples showed chronic toxicity at 96 hours (EC50<100%).     

Toxicological evaluation of nitrofurazone and furaltadone on Selenastrum capricornutum, Daphnia magna, and Musca domestica

Short-term toxicity of nitrofurans, nitrofurazone, furaltadone tartrate, and furaltadone chlorohydrate, was tested in the laboratory on two freshwater organisms, Selenastrum capricornutum (algae) and Daphnia magna (crustaceans). Toxicity studies with nitrofurazone were also carried out on larval development of the house fly Musca domestica L. Nitrofurazone was invariably the most toxic compound (the 96-hr EC50 of algal species was 1.45 mg/liters; the EC50 values for D. magna were 40.04 and 28.67 mg/liter after 24 and 48 hr, respectively) followed by furaltadone tartrate and furaltadone chlorohydrate. This study provides some evidence of the potential ecotoxicity of nitrofurans, indicating the need for further investigations.     

Acute and chronic toxicity of technical-grade pesticides to glochidia and juveniles of freshwater mussels (Unionidae)

Chemical contaminants are among many potential factors involved in the decline of freshwater mussel populations in North America, and the effects of pesticides on early life stages of unionid mussels are largely unknown. The objective of this study was to determine the toxicity of technical-grade current-use pesticides to glochidia and juvenile life stages of freshwater mussels. We performed acute toxicity tests with glochidia (five species) and juveniles (two species) exposed to a suite of current-use pesticides including herbicides (atrazine and pendimethalin), insecticides (fipronil and permethrin), and a reference toxicant (NaCl). Because of limited availability of test organisms, not all species were tested with all pesticides. Toxicity tests with fungicides (chlorothalonil, propiconazole, and pyraclostrobin) were performed with one species (Lampsilis siliquoidea). Lampsilis siliquoidea glochidia and juveniles were highly sensitive to the fungicides tested but the technical-grade herbicides and insecticides, at concentrations approaching water solubility, were not acutely toxic to this or the other unionid species. In a 21-d chronic test with four-month-old juvenile L. siliquoidea, the 21-d median effective concentration (EC50) with atrazine was 4.3 mg/L and in atrazine treatments >or=3.8 mg/L mussel growth was significantly less than controls. The relatively high sensitivity of L. siliquoidea to chlorothalonil, propiconazole, and pyraclostrobin is similar to that reported for other aquatic organisms commonly used for toxicity testing. The relative risk associated with acute exposure of early life stages of mussels to technical-grade atrazine, pendimethalin, fipronil, and permethrin is likely low; however, survival and growth results with juvenile L. siliquoidea indicate that chronic exposure to high concentrations (>/=3.8 mg/L) of atrazine may have the potential to impact mussel populations and warrants further investigation.     

Acute toxicity of locust insecticides to two indigenous invertebrates from Sahelian temporary ponds

During desert locust plagues large amounts of insecticides are used for control operations. Drift from these treatments and accidental overspraying may contaminate small surface waters such as temporary ponds. The present study describes methods for static acute toxicity tests with two abundant organisms that occur in temporary ponds in the African Sahel region: the fairy shrimp Streptocephalus sudanicus Daday (Branchiopoda, Anostraca, Streptocephalidae) and the backswimmer Anisops sardeus Herrich-Sch?ffer (Hemiptera, Notonectidae). The organisms were captured in the field and 48-h static toxicity tests were conducted in the laboratory. The assays were used to screen the toxicity of 11 formulated synthetic insecticides used in desert locust control and of spores of the mycopesticide Metarhizium anisopliae var. acridum. Most of the synthetic insecticides tested were highly toxic to both organisms (LC50 or EC50<1 mg/L). Exceptions were the toxicity of diflubenzuron to A. sardeus (moderately toxic: 1相似文献   

Acute toxicity of copper, ammonia, and chlorine to glochidia and juveniles of freshwater mussels (Unionidae)

The objective of the present study was to determine acute toxicity of copper, ammonia, or chlorine to larval (glochidia) and juvenile mussels using the recently published American Society for Testing and Materials (ASTM) Standard guide for conducting laboratory toxicity tests with freshwater mussels. Toxicity tests were conducted with glochidia (24- to 48-h exposures) and juveniles (96-h exposures) of up to 11 mussel species in reconstituted ASTM hard water using copper, ammonia, or chlorine as a toxicant. Copper and ammonia tests also were conducted with five commonly tested species, including cladocerans (Daphnia magna and Ceriodaphnia dubia; 48-h exposures), amphipod (Hyalella azteca; 48-h exposures), rainbow trout (Oncorhynchus mykiss; 96-h exposures), and fathead minnow (Pimephales promelas; 96-h exposures). Median effective concentrations (EC50s) for commonly tested species were >58 microg Cu/L (except 15 microg Cu/L for C. dubia) and >13 mg total ammonia N/L, whereas the EC50s for mussels in most cases were <45 microg Cu/L or <12 mg N/L and were often at or below the final acute values (FAVs) used to derive the U.S. Environmental Protection Agency 1996 acute water quality criterion (WQC) for copper and 1999 acute WQC for ammonia. However, the chlorine EC50s for mussels generally were >40 microg/L and above the FAV in the WQC for chlorine. The results indicate that the early life stages of mussels generally were more sensitive to copper and ammonia than other organisms and that, including mussel toxicity data in a revision to the WQC, would lower the WQC for copper or ammonia. Furthermore, including additional mussel data in 2007 WQC for copper based on biotic ligand model would further lower the WQC.     

Toxicity of the herbicide glyphosate and several of its formulations to fish and aquatic invertebrates

Studies were initiated to determine the acute toxicity of technical grade glyphosate (MON0573), the isopropylamine salt of glyphosate (MON0139), the formulated herbicide Roundup^® (MON02139), and the Roundup^® surfactant (MON0818) to four aquatic invertebrates and four fishes: daphnids (Daphnia magna), scuds (Gammarus pseudolimnaeus), midge larvae (Chironomous plumosus), mayfly nymphs (Ephemerella walkeri), Rainbow trout (Salmo gairdneri), fathead minnows (Pimephales promelas), channel catfish (Ictalurus punctatus), and bluegills (Lepomis macrochirus). Acute toxicities for Roundup ranged from 2.3 mg/L (96-h LC50, fathead minnow) to 43 mg/L (48-h EC50, mature scuds). Toxicities of the surfactant were similar to those of the Roundup formulation. Technical glyphosate was considerably less toxic than Roundup or the surfactant; for midge larvae, the 48-h EC50 was 55 mg/L and for rainbow trout, the 96-h LC50 was 140 mg/L. Roundup was more toxic to rainbow trout and bluegills at the higher test temperatures, and at pH 7.5 than at pH 6.5. Toxicity did not increase at pH 8.5 or 9.5. Eyed eggs were the least sensitive life stage, but toxicity increased markedly as the fish entered the sac fry and early swim-up stages. No changes in fecundity or gonadosomatic index were observed in adult rainbow trout treated with the isopropylamine salt or Roundup up to 2.0 mg/L. The aging of Roundup test solutions for seven days did not reduce toxicity to midge larvae, rainbow trout or bluegills. In avoidance studies, rainbow trout did not avoid concentrations of the isopropylamine salt up to 10.0 mg/L; mayfly nymphs avoided 10.0 mg/L of Roundup, but not 1.0 mg/L. In a simulated field application, midge larvae avoided 2.0 mg/L of Roundup. Application of Roundup, at recommended rates, along ditchbank areas of irrigation canals should not adversely affect resident populations of fish or invertebrates. However, spring applications in lentic situations, where dissolved oxygen levels are low or temperatures are elevated, could be hazardous to young-of-the-year-fishes.     

Acute effects of road salts and associated cyanide compounds on the early life stages of the unionid mussel Villosa iris

The toxicity of cyanide to the early life stages of freshwater mussels (order Unionida) has remained unexplored. Cyanide is known to be acutely toxic to other aquatic organisms. Cyanide-containing compounds, such as sodium ferrocyanide and ferric ferrocyanide, are commonly added to road deicing salts as anticaking agents. The purpose of the present study was to assess the acute toxicity of three cyanide compounds (sodium cyanide, sodium ferrocyanide, and ferric ferrocyanide), two road salts containing cyanide anticaking agents (Morton and Cargill brands), a brine deicing solution (Liquidow brand), and a reference salt (sodium chloride) on glochidia (larvae) and juveniles of the freshwater mussel Villosa iris. Sodium ferrocyanide and ferric ferrocyanide were not acutely toxic to glochidia and juvenile mussels at concentrations up to 1,000 mg/L and 100 mg/L, respectively. Lowest observed effect concentrations (LOECs) for these two chemicals ranged from 10 to >1,000 mg/L. Sodium cyanide was acutely toxic to juvenile mussels, with a 96-h median effective concentration (EC50) of 1.10 mg/L, although glochidia tolerated concentrations up to 10 mg/L. The EC50s for sodium chloride, Liquidow brine, Morton road salt, and Cargill road salt were not significantly different for tests within the same life stage and test duration (range, 1.66-4.92 g/L). These results indicate that cyanide-containing anticaking agents do not exacerbate the toxicity of road salts, but that the use of road salts and brine solutions for deicing or dust control on roads may warrant further investigation.     

Using accelerated life testing procedures to compare the relative sensitivity of rainbow trout and the federally listed threatened bull trout to three commonly used rangeland herbicides (picloram, 2,4-D, and clopyralid)

We conducted 96-h static acute toxicity studies to evaluate the relative sensitivity of juveniles of the threatened bull trout (Salvelinus confluentus) and the standard cold-water surrogate rainbow trout (Onchorhyncus mykiss) to three rangeland herbicides commonly used for controlling invasive weeds in the northwestern United States. Relative species sensitivity was compared using three procedures: standard acute toxicity testing, fractional estimates of lethal concentrations, and accelerated life testing chronic estimation procedures. The acutely lethal concentrations (ALC) resulting in 50% mortality at 96 h (96-h ALC50s) were determined using linear regression and indicated that the three herbicides were toxic in the order of picloram acid > 2,4-D acid > clopyralid acid. The 96-h ALC50 values for rainbow trout were as follows: picloram, 41 mg/L; 2.4-D, 707 mg/L; and clopyralid, 700 mg/L. The 96-h ALC50 values for bull trout were as follows: picloram, 24 mg/L; 2.4-D, 398 mg/L; and clopyralid, 802 mg/L. Fractional estimates of safe concentrations, based on 5% of the 96-h ALC50, were conservative (overestimated toxicity) of regression-derived 96-h ALC5 values by an order of magnitude. Accelerated life testing procedures were used to estimate chronic lethal concentrations (CLC) resulting in 1% mortality at 30 d (30-d CLC1) for the three herbicides: picloram (1 mg/L rainbow trout, 5 mg/L bull trout), 2,4-D (56 mg/L rainbow trout, 84 mg/L bull trout), and clopyralid (477 mg/L rainbow trout; 552 mg/L bull trout). Collectively, the results indicated that the standard surrogate rainbow trout is similar in sensitivity to bull trout. Accelerated life testing procedures provided cost-effective, statistically defensible methods for estimating safe chronic concentrations (30-d CLC1s) of herbicides from acute toxicity data because they use statistical models based on the entire mortality:concentration:time data matrix.     

Environmental assessment of Norwegian priority pharmaceuticals based on the EMEA guideline

An environmental risk assessment of eleven pharmaceuticals according to the guideline recommended by the European Medicines Evaluation Agency (EMEA) was performed. Cefuroxime, ciprofloxacin, cyclophosphamide, diclofenac, ethinylestradiol, ibuprofen, metoprolol, paracetamol, sulfamethoxazole, tetracycline and trimethoprim were selected for assessment by the Norwegian Pollution Control Authority. Predicted environmental concentrations (PECs) were calculated according to both the EMEA guideline and a conventional model for comparison and ranged from 0.0002 to 45 microg/L. Available acute and chronic toxicity data were collected from the literature, although no data were available for cyclophosphamide. Toxicity tests showed cyclophosphamide to have relatively low acute toxicity with an EC50 for Pseudokirchneriella subcapitata >100 mg/L and a Daphnia magna reproduction NOEC of 56 mg/L. These and the literature data were used to derive predicted no effect concentrations (PNEC). Risk quotients (PEC/PNEC) were then calculated for all 11 pharmaceutical compounds. Risk quotients greater than 1 were obtained for ciprofloxacin, diclofenac, ethinylestradiol, sulfamethoxazole and tetracycline according to the EMEA guideline. Measured environmental concentrations (MECs) confirmed that the release of ciprofloxacin from wastewater treatment works may potentially be of environmental concern in Norway.     

强效杀生剂水生毒理学毒性评价研究

目的研究中央空调循环冷却水中杀生剂的生态安全性,探讨其毒性评价方法。方法采用大型水蚤急性毒性试验、卤虫无节幼体急性毒性试验和斜生栅藻生长抑制试验对强效杀生剂的生态毒性进行评价,用直线内插法计算EC50值及LC50值。结果强效杀生剂对大型水蚤的半数致死浓度24、48、96 h LC50分别为0.004 4、0.001 2及0.000 8 mg/L,半数影响浓度24、48、96 h EC50分别为0.002 7、0.001 3、0.000 8 mg/L。强效杀生剂对卤虫无节幼体的半数致死浓度24、48、96 h LC50分别为0.096、0.048、0.032 mg/L。强效杀生剂对斜生栅藻的半数影响浓度24、48和96 h EC50分别为57、28及1.62 mg/L。结论强效杀生剂对大型水蚤和斜生栅藻有较强的毒性,因此对水环境中的生物具有较强的生态毒性,应该加强对其使用的管理。