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     

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.     

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%.     

Survival, mobility, and membrane-bound enzyme activities of freshwater planarian, Dugesia japonica, exposed to synthetic and natural surfactants

Surfactants are a major class of emerging pollutants widely used in large quantities in everyday life and commonly found in surface waters worldwide. Freshwater planarian was selected to examine the effects of different surfactants by measuring mortality, mobility, and membrane-bound enzyme activities. Among the 10 surfactants tested, the acute toxicities of betaine and polyethylene glycol (PEG-200) to planarians were relatively low, with a median lethal concentration (LC50) greater than 10,000 mg/L. The toxicity to planarians of the other eight surfactants based on 48-h LC50 could be arranged in the descending order of cetylpyridinum chloride (CPC)?>?4-tert-octylphenol (4-tert-OP)?>?ammonium lauryl sulfate?>?benzalkonium chloride?>?saponin?>?sodium lauroylsarcosinate?>?dioctyl sulfosuccinate?>?dodecyl trimethyl ammonium bromide (DTAB). Both CPC and 4-tert-OP were very toxic to planarians, with 48-h LC50 values <1 mg/L. The median effective concentrations (EC50s) of planarian mobility were in the 0.1 to 50 mg/L range and were in the same range as the 24-h LC50 of planarians exposed to different surfactants, except for DTAB. In addition, significant inhibition of cholinesterase activity activities was found in planarians exposed to 4-tert-OP at 2.5 and 5 mg/L and to saponin at 10 mg/L after 2-h treatments. This result suggests that planarian mobility responses can be used as an alternative indicator for acute toxicity of surfactants after a very short exposure period.     

Toxicity of the fluoroquinolone antibiotics enrofloxacin and ciprofloxacin to photoautotrophic aquatic organisms

The present study investigated the growth inhibition effect of the fluoroquinolone antibiotics enrofloxacin and ciprofloxacin on four photoautotrophic aquatic species: the freshwater microalga Desmodesmus subspicatus, the cyanobacterium Anabaena flos-aquae, the monocotyledonous macrophyte Lemna minor, and the dicotyledonous macrophyte Myriophyllum spicatum. Both antibiotics, which act by inhibiting the bacterial DNA gyrase, demonstrated high toxicity to A. flos-aquae and L. minor and moderate to slight toxicity to D. subspicatus and M. spicatum. The cyanobacterium was the most sensitive species with median effective concentration (EC50) values of 173 and 10.2 μg/L for enrofloxacin and ciprofloxacin, respectively. Lemna minor proved to be similarly sensitive, with EC50 values of 107 and 62.5 μg/L for enrofloxacin and ciprofloxacin, respectively. While enrofloxacin was more toxic to green algae, ciprofloxacin was more toxic to cyanobacteria. Calculated EC50s for D. subspicatus were 5,568 μg/L and >8,042 μg/L for enrofloxacin and ciprofloxacin, respectively. These data, as well as effect data from the literature, were compared with predicted and reported environmental concentrations. For two of the four species, a risk was identified at ciprofloxacin concentrations found in surface waters, sewage treatment plant influents and effluents, as well as in hospital effluents. For ciprofloxacin the results of the present study indicate a risk even at the predicted environmental concentration. In contrast, for enrofloxacin no risk was identified at predicted and measured concentrations.     

Determination of wastewater LC50 of the different process stages of the textile industry

Textile plants are very important sources of toxic discharges. The purpose of the research described in this paper was to use bioassays with daphnids to determine the LC50 values of textile wastewater samples taken from different stages of the finishing textile industry. Toxicity due to dyeing, chlorination, and the absence of adequate physicochemical conditions for daphnid survival were considered. Wastewater samples corresponding to each process stage were collected at five finishing textile industries and assayed according to previously published procedures. The sensitivity of daphnids to chemicals was assayed using sodium dodecyl sulfate and was similar to other reports (14.6+/-6.8 vs 14.5+/-2.3 mg/L). All effluents from the five company samples were toxic in terms of LC50 and exhibited very high toxicity with acute toxicity unit (ATU) levels between 2.2 and 960, indicating that the five textile industries produced toxic water. The sensory characteristics indicated that the dyes contributed to overall sample toxicity at all process stages. The most toxic contaminant seemed to be ClO- at levels between 0.2 and 6.8 mg/L, suggesting that further research is needed on the economic costs of stage-by-stage and total effluent treatments.     

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 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.     

Is chronic detergent ingestion harmful to the gut?

Synthetic detergents are used in large quantities as household and industrial cleaners. Because of the common practice of leaving dishes washed in detergent solutions to dry without rinsing these compounds are ingested. We have calculated that an adult takes in about 1 mg/kg detergent a day and babies can be administered between seven and 10 mg/kg a day. Rats were fed a dose of 100 mg/kg a day in a pilot experiment and gross abnormalities were found in the gastrointestinal tract, the most striking being subtotal villous atrophy of the small bowel mucosa and glandular atrophy in the colon. These changes were not reversible 12 weeks after cessation of detergent administration.     

Acute toxicity of oxygenated and nonoxygenated imidazolium-based ionic liquids to Daphnia magna and Vibrio fischeri

Room-temperature ionic liquids (RTILs) recently have generated great interest as a result of their potential commercial applications. In particular, because of their negligible vapor pressure and low inflammability, they have been suggested as green alternatives to traditional organic solvents. The toxicity and potential environmental risk of this heterogeneous class of chemicals, however, are poorly understood. An alkyl-substituted RTIL, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)]), is one of the most widely used cations of RTILs, and information regarding its toxicity is relatively extensive. On the other hand, oxygenated chain-substituted ionic liquids, 1-methoxyethyl-3-methylimidazolium salts (moemims), are a new class of RTILs that have been poorly studied. Here, we compared the acute toxicity of [bmim][BF(4)] and moemims to the crustacean Daphnia magna (end point, 48-h immobilization) and the bacterium Vibrio fischeri (end point, 15-min inhibition of bioluminescence). The concentrations of [bmim][BF(4)] resulting in 50% of the maximum adverse effect (EC50s) for D. magna and V. fischeri were 5.18 and 300 mg/L, respectively, and were consistent with previously published values. The EC50s of the two moemims for D. magna are very similar, ranging from 209 to 222 mg/L in different experimental trials, and are higher by two orders of magnitude than the EC50 of [bmim][BF(4)]. The EC50s of 1-methoxyethyl-3-methylimidazolium tetrafluoroborate ([moemim][BF(4)]) and 1-methoxyethyl-3-methylimidazolium dicyanamide ([moemim][dca]) for V. fischeri are 3,196 and 2,406 mg/L, respectively. Results indicate that introduction of an oxygenated side chain in the imidazolium cation can greatly reduce the toxicity of RTILs and that these RTILs are less toxic than commonly used chlorinated solvents, such as tricloromethane, but are more toxic than nonchlorinated solvent, such as methanol and acetone.     

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).     

Ecotoxicological characterization of industrial wastewater--sulfite pulp mill with bleaching

Different process wastewaters from a sulfite pulp mill with bleaching were characterized by chemical analysis and toxicity tests. The amount of adsorbable organically bound halogen (AOX) from the bleachery was 3.6 kg per ton pulp. The extractable organically bound chlorine was 15% of AOX. Some identified organochlorine compounds in the effluent could be traced in the receiving water. Effluents from the chlorination and alkaline extraction stages and the condensate were the main contributors to the effluent toxicity. The effluents were particularly toxic to the alga Skeletonema costatum. The EC50 value for growth of the alga was 24-29 ml/liter of the total effluent. The toxicity cannot be ascribed to single chemical components in the effluents. Degradation of toxic components occurs after dilution of the effluents in the receiving water. The toxicity may be reduced to 30-50% of the initial toxicity within 1 week. Predictions of toxic effects in the receiving water, based on results of toxicity tests and estimated dilution, indicate that large areas are affected by the discharges. Som observations of the distribution of organisms in the receiving water indicate that predictions from the toxicity tests may be valid.     

Comparative Aquatic Toxicity Evaluation of 2-(Thiocyanomethylthio)benzothiazole and Selected Degradation Products Using Ceriodaphnia dubia

2-(Thiocyanomethylthio)benzothiazole (TCMTB) is a biocide used in the leather, pulp and paper, and water-treatment industries. TCMTB may enter aquatic ecosystems during its manufacture and use. TCMTB is environmentally unstable; therefore, it is important to evaluate the toxicity of the more persistent degradation products. This study compared the toxicity of TCMTB with its degradation products 2-mercaptobenzothiazole (2-MBT), 2-(methylthio)benzothiazole (MTBT), benzothiazole (BT), and 2-hydroxybenzothiazole (HOBT). Toxicity was determined using Ceriodaphnia dubia 48-hour acute and 7-day chronic test protocols. TCMTB was the most toxic compound evaluated in both the acute and chronic tests with EC50s of 15.3 and 9.64 g/L, respectively. 2-MBT, the first degradation product, was the second most toxic compound with acute and chronic EC50s of 4.19 and 1.25 mg/L, respectively. The toxicity of MTBT and HOBT were similar with acute EC50s of 12.7 and 15.1 mg/L and chronic EC50s of 6.36 and 8.31 mg/L, respectively. The least toxic compound was BT with acute and chronic EC50s of 24.6 and 54.9 mg/L, respectively. TCMTB was orders of magnitude more toxic than its degradation products. Toxicity data on these benzothiazole degradation products is important because of concerns regarding their release, degradation, persistence, and non–target organism effects in aquatic ecosystems.     

Acute toxicity of thioarsenates to Vibrio fischeri

Thioarsenic species often are the predominant arsenic species in sulfidic environments, yet little is known about their toxicity. We report to our knowledge the first determination of acute toxicity of mono-, di-, and trithioarsenate to the bioluminescent bacterium Vibrio fischeri, which increases with an increasing number of thio(SH)-groups. Whereas mono- and dithioarsenate are much less toxic (effective analyte concentration causing a 50% decrease in luminescence [EC50], 676 and 158 mg/L, respectively), the toxicity of trithioarsenate (EC50, 14.4 mg/L) is comparable to the toxicities of arsenate and arsenite (EC50, 9.1 and 26.1 mg/L, respectively). The low toxicity of monothioarsenate is remarkable, because it has chemical properties very similar to those of arsenate. In contrast to the toxicities of arsenite and arsenate, the toxicity of thioarsenates increases with exposure time, suggesting a lack of detoxification mechanisms or a conversion of thioarsenic species into arsenic oxyanions after uptake. We determined the acute toxicity of synthetic arsenite solutions with varying sulfide concentration to V. fischeri. Arsenic speciation in these solutions was measured by ion chromatography-inductively coupled plasma-mass spectrometry, and the observed toxicity was related to the different arsenic species present. High inhibition of luminescence was observed at low and high ratios of sulfur to arsenic, in which arsenite or a mixture of di-, tri-, and tetrathioarsenate dominated arsenic speciation. Acute toxicity decreased at sulfur to arsenic ratios of from 1 to 10, with a minimum luminescence inhibition of 30% at a ratio of 3.5, at which concentrations of 55 mg/L of arsenite and 30 mg/L of trithioarsenate were determined. The toxicity observed under these conditions is much lower than that anticipated from the individual dose-response curves that predict each species alone already should cause 70 to 80% inhibition. The low toxicity suggests an antagonistic toxicological interaction between arsenite and trithioarsenate.     

Chronic toxicities of surfactants and detergent builders to algae: a review and risk assessment

Surfactants are high volume chemicals used primarily in detergent products and are found in natural waters. The toxic effects of representative surfactants on aquatic life have been determined and summarized in greater detail for animal test species than for aquatic vegetation. This paper summarizes the chronic toxicity levels for algae, an important trophic level in aquatic ecosystems. Toxic effects have been determined for a few commercially important surfactants and primarily for cultured freshwater algae under the controlled conditions of the laboratory where inhibition, and in some cases, stimulation have been observed. The reported toxicities of surfactants have varied widely over several orders of magnitude and the effect levels are compound and species-specific. Species sensitivity can vary as much as three orders of magnitude to the same surfactant and the effects of different surfactants on the same algal species can vary as much as four orders of magnitude. Therefore, data generalizations and extrapolations are difficult but anionic and nonionic surfactants and detergent builders are relatively non-toxic when compared to various cationic monoalkyl and dialkyl quaternary ammonium salts. Recent toxicity studies conducted in the field monitoring the effects of several surfactants used in commercial products on various structural and functional parameters of natural algal communities have shown toxicity to be less in many cases than that predicted from laboratory tests. Furthermore, the field-derived effect levels typically exceed the reported measured environmental levels of the corresponding surfactants indicating the likelihood of no impact. Additional field studies are needed to substantiate this trend for these and other commercially important surfactants particularly for natural saltwater algal assemblages for which the toxicity data base is unavailable.     

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%).     

Toxicity and hazard of selective serotonin reuptake inhibitor antidepressants fluoxetine, fluvoxamine, and sertraline to algae

The toxicity of SSRIs to algae/phytoplankton was investigated using the US EPA ECOSAR, acute single-species growth inhibition assays, species sensitivity distributions (SSDs), and an outdoor microcosm mixture experiment. Worst-case ECOSAR estimates of SSRI toxicity to algae ranged from 0.73 to 13.08 mg/L. Sertraline was the most toxic SSRI tested in single-species growth inhibition assays followed by fluoxetine and fluvoxamine with worst-case 96-h IC10s of 4.6, 31.3, and 1662 microg/L, respectively. HC5s of 2.4, 3.6, and 1100 microg/L were estimated, respectively, for sertraline, fluoxetine, and fluvoxamine toxicity to algae-using SSDs. Microcosm phytoplankton structural endpoints were more sensitive than functional endpoints in the short term. However, in the long term, structural endpoints were resilient and functional endpoints remained impacted even after a period of recovery. The worst-case EC10 determined from the outdoor microcosm mixture toxicity to phytoplankton communities was 15.2 nM. Although SSRIs are toxic to algae, hazard quotients using worst-case PECs represent a margin of safety of 20 to phytoplankton. Although SSRIs do not appear to pose a hazard to primary production, this assessment is not protective of higher aquatic organisms and further research into the chronic toxicity to low levels of SSRIs to higher-level aquatic species is recommended.     

Effect of 2,4-dihydroxybenzophenone (BP1) on early life-stage development of the marine copepod Acartia tonsa at different temperatures and salinities

Benzophenone (BP)-type ultraviolet (UV) filters are widely used in cosmetic and sunscreen products and can enter the aquatic environment. Therefore, we investigated the subchronic toxicity of 2,4-dihydroxybenzophenone (BP1) on the marine calanoid copepod Acartia tonsa in an early life-stage development study. Since developmental endpoints depend on environmental conditions, a preceding study of A. tonsa development was performed at three temperatures, four salinities, four light:dark regimes, six food densities, and four culture densities. Times elapsed until 50% of the population had reached a copepodite stage (DT(?) ) at the different conditions were calculated. The DT(?) values decreased from 296?h at 15°C to 89?h at 25°C and were also affected by salinity (126?h at 15‰ and 167?h at 30‰), whereas the light:dark regime and culture density influenced development only to a minor extent. BP1 was found acutely toxic at 2.6?mg/L (48-h median lethal concentration [LC50]). The toxicity of BP1 on early life-stage development was studied in combinations of three temperatures (15, 20, 25°C) and three salinities (15, 20, 25‰) using five toxicant concentrations between 0.051 and 2?mg/L in each scenario. Concentrations causing 10 and 50% inhibition of development (EC10 and EC50) were determined. Acartia tonsa was most resistant towards BP1 at 20°C where an EC50 of 1.1?mg/L was found, whereas EC50 values were significantly lower at 15°C (0.49?mg/L) and 25°C (0.77?mg/L), respectively. The EC50 also decreased with increasing salinity. Our results demonstrate that environmental conditions do influence toxicity test results; thus, they need to be considered carefully when developing test protocols as well as for environmental risk assessments of chemicals.     

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.     

Comparison of porewater and elutriate bivalve larval development toxicity testing in a sediment quality triad framework

Concurrent porewater (PW) and elutriate (ELU) toxicity testing using newly fertilized larvae of the bivalve Mytilus galloprovincialis was conducted as part of sediment quality triad (SQT) investigations for urban harbor locations. PW samples were consistently more toxic to bivalve larvae than the corresponding ELU sample, including samples collected from uncontaminated reference locations. Ammonia was identified as the most likely toxic agent. EC(20) and EC(50) values of 0.028 and 0.036mg/L un-ionized N, respectively, were determined for M. galloprovincialis. The limitations of incorporating PW bivalve larval development toxicity tests using M. galloprovincialis for routine SQT investigations, as well as possible alternative methods, are discussed.