Comparison of species sensitivity distributions for species from China and the USA

China has recently commenced water quality criteria (WQC) research using the species sensitivity distribution (SSD) method; however, it is difficult to obtain sufficient native species toxicity data for thousands of contaminants. In this study, the feasibility of using non-native toxicity data in deriving native WQC was analyzed. We constructed SSDs based on acute toxicity data of species from China and the USA for eight priority pollutants, and compared the sensitivities of different taxonomic groups between the two countries. The results showed that the SSD method of log-logistic distribution fit the toxicity data of different taxa well. The comparison of sensitivity distribution and hazardous concentration for 5 % of the species and 50 % of the species showed that there was no significant difference between Chinese and American taxa. It could be feasible to use toxicity data from the USA to provide a temporary way to protect organisms in China in emergency situations or for management of priority pollutants when native toxicity data are lacking.     

Acute toxicity of chlorophenols to earthworms using a simple paper contact method and comparison with toxicities to fresh water organisms

An acute toxicity test of chlorophenols on earthworms (Eisenia fetida) was performed using a simple paper contact method proposed by OECD testing guideline no. 207, that were applied as an earthworm toxicity test. The median lethal concentration, EC50, had significant correlation with logP(ow) (1-octanol/water partition coefficient) of the chemicals. The toxicity of chlorophenols on E. fetida was compared with toxicities for other species: an algae (Selenostrum capricornutum), a crustacean (Daphnia magna), and a fish (Oryzias latipes). It was found that the toxicity of chlorophenols was almost same for E. fetida and for fresh water organisms. These results suggest the possibility of drawing correlations between the effects of pollutants on living things in different environments, fresh water and soil.     

Comparative toxicity of acrylic acid to marine and freshwater microalgae and the significance for environmental effects assessments.

In this study, we compared the sensitivity of freshwater and marine organisms to two structurally similar substances, acrylic acid and methacrylic acid. Reported acute toxicity data (L(E)C50-values) for freshwater organisms range from 0.1 to 222 mg/l and 85 to >130 mg/l for acrylic acid and methacrylic acid, respectively. The large variation in toxicity data for acrylic acid is due to a specific toxicity to certain species of freshwater microalgae, with algae EC50-values being two to three orders of magnitude lower than L(E)C50-values reported for fish and invertebrates. To evaluate the sensitivity of marine organisms, ecotoxicity data was generated for ten species of microalgae, one invertebrate species and one fish species. For methacrylic acid, we found a marine acute toxicity that ranged from 110 to >1260 mg/l, which is comparable to reported data on freshwater organisms. In strong contrast, the resulting L(E)C50-values for acrylic acid ranged from 50 to >1000 mg/l, and there was no specific sensitivity of marine algae when compared to marine invertebrates and fish. For acrylic acid, therefore, use of the available freshwater toxicity data for an effects assessment for the marine environment is likely to overestimate the hazard and risk from this substance. Overall, the results of the study suggest that ecotoxicity data generated on freshwater species may not always be appropriate for the effects assessments of organic chemicals in the marine environment, thus emphasising the importance of using ecologically relevant data to assess environmental risk.     

Assessing single and joint effects of chemicals on the survival and reproduction of Folsomia candida (Collembola) in soil

Chemicals are often found in the environment as complex mixtures. There has been a large effort in the last decade to assess the combined effect of chemicals, using the conceptual models of Concentration Addition and Independent Action, but also including synergistic, antagonistic, dose-level and dose-ratio dependent deviations from these models. In the present study, single and mixture toxicity of atrazine, dimethoate, lindane, zinc and cadmium were studied in Folsomia candida, assessing survival and reproduction. Different response patterns were observed for the different endpoints and synergistic patterns were observed when pesticides were present. Compared with the previously tested Enchytraeus albidus and Porcellionides pruinosus, the mixture toxicity pattern for F. candida was species specific. The present study highlights the importance of studying toxicity of chemicals mixtures due to the observed potentiation of effects and confirms that for an adequate ecologically relevant risk assessment different organisms and endpoints should be included.     

Ecotoxicological Characterisation and Classification of Existing Chemicals

GOAL, SCOPE AND BACKGROUND: In 1998, the International Council of Chemical Associations (ICCA) launched a global initiative to investigate more than 1,000 HPV chemicals (High Production Volume, > or = 1,000 t/a) within the refocused OECD HPV Chemicals Programme. Up to the OECD SIDS Initial Assessment Meeting in April 2004 (SIAM 18) 147 ICCA dossiers (ca. 230 CAS-No) have been assessed based on a harmonised data set. The environmental profile and an ecotoxicological characterisation of these chemicals are presented here. Data for acute aquatic toxicity were correlated among each other, as well as data for fish (LC50, LD50) and rodents (LD50). The data for acute aquatic toxicity are compared with other existing chemicals. METHODS: Data of the ICCA HPV chemicals from the OECD SIAM 11-18 are presented for: log Kow (as an indicator for bioaccumulation potential), biodegradation, acute aquatic toxicity and availability of long-term toxicity data. Correlation analysis was performed with log transformed data and a linear regression model was fitted to the data, if a significant correlation was found. Acute toxicity for fish and acute oral toxicity for rodents were correlated on a molar basis. Acute aquatic toxicity of the chemicals is compared with data from BUA reports 1-234 and a random EINECS sample (Knacker et al. 1995). RESULTS AND DISCUSSION: According to the dossier information, 71 of the 147 ICCA chemicals are not 'readily biodegradable', 21 have a log Kow > or = 3, and 44 are 'toxic' (LC/EC50 < or = 10 mg/L) or 'very toxic' (LC/EC50 < or = 1 mg/L) to aquatic organisms. For 77, only the base set (acute fish, Daphnia and algae) is available, for the rest at least one long-term test (fish or Daphnia) is available and three tests for a mere 14 others. Based on the data presented, the SIAM gives recommendations for Environment and Human Health. 22 chemicals have been identified as a 'candidate for further work' for Environment and 16 for Human Health. The highest correlation coefficient was obtained correlating fish and Daphnia (r2 = 0.79). LC50 (fish) is significantly correlated with LD50 (rodent), but data are widely scattered. The correlation is not improved after transforming LC50 (fish) to LD50 (fish), using BCF QSAR. Based on acute aquatic toxicity, 25.1% of the chemicals from the BUA reports 1-234 are classified as 'very toxic' (LC/EC50 < or = 1 mg/L). This proportion is 2.5-fold higher than the ICCA HPV chemicals and 1.4-fold higher than the random EINECS sample. CONCLUSIONS: Correlation coefficients for aquatic toxicity data are rather uniform (0.57-0.79) compared with literature data, but also the best correlation was observed between fish and Daphnia. Because the scatter around the regression lines is still considerable, simple predictions of ecotoxicity between species are not possible. Correlation of LC50 (fish) and LD50 (rodent) indicates that toxicity is different. Surprisingly, the correlation of fish and rodent toxicity is not improved by transforming LC50 values to internal LD50s. The selection of ICCA chemicals by market significance (production volume) leads to a classification of toxicity, which is more comparable to a random sample of EINECS chemicals than to German BUA chemicals. The latter were chosen for concern (for Environment or Human Health). RECOMMENDATIONS AND OUTLOOK: Of 147 dossiers assessed between SIAM 11-18, ca. 75% were sponsored by the three following countries: Germany (42), USA (37) and Japan (33). The current output is about 50 dossiers per year (70-100 CAS-No), but a trend for an increase of output is noticeable. Industry, national authorities, and OECD work on a further development to speed up the output. The number of chemicals with 'low priority for further work' and the work recommended for the 'candidates' (mainly exposure assessment) indicate that the data presented were adequate for an initial hazard assessment according to OECD requirements. From the ICCA HPV list (n = 880, state of 1999) 44% of the chemicals have data available to cover all SIDS endpoints for Environment and only 33% for Human Health (Allanou et al. 1999). This indicates the importance of the Initiative to provide information on existing chemicals. The authors agree with the expectation "...that the scientific information provided by this global initiative will be considered as an internationally accepted and harmonised basis for further steps of chemicals management." (ICCA 2002 b).     

Classifying environmental pollutants: Part 3. External validation of the classification system

In order to validate a classification system for the prediction of the toxic effect concentrations of organic environmental pollutants to fish, all available fish acute toxicity data were retrieved from the ECETOC database, a database of quality-evaluated aquatic toxicity measurements created and maintained by the European Centre for the Ecotoxicology and Toxicology of Chemicals. The individual chemicals for which these data were available were classified according to the rulebase under consideration and predictions of effect concentrations or ranges of possible effect concentrations were generated. These predictions were compared to the actual toxicity data retrieved from the database. The results of this comparison show that generally, the classification system provides adequate predictions of either the aquatic toxicity (class 1) or the possible range of toxicity (other classes) of organic compounds. A slight underestimation of effect concentrations occurs for some highly water soluble, reactive chemicals with low log K(ow) values. On the other end of the scale, some compounds that are classified as belonging to a relatively toxic class appear to belong to the so-called baseline toxicity compounds. For some of these, additional classification rules are proposed. Furthermore, some groups of compounds cannot be classified, although they should be amenable to predictions. For these compounds additional research as to class membership and associated prediction rules is proposed.     

Comparative study on the environmental risk induced by several pyrethroids in estuarine and freshwater invertebrate organisms

The acute toxicity of permethrin, resmethrin, and cypermethrin to four species of aquatic non-target invertebrate organisms, found in estuarine and freshwater ecosystems, was evaluated. Artemia franciscana and Brachionus plicatilis larvae, as estuarine organisms, and Brachionus calyciflorus and Thamnocephalus platyurus larvae, as freshwater organisms, were exposed for 24 h to concentrations of these pyrethroids, and the LC(50) values were compared. The freshwater organisms were more sensitive to these pyrethroids than estuarine organisms tested. A. franciscana larvae were more tolerant organisms than B. plicatilis larvae. The freshwater organisms tested have demonstrated to be a good alternative to the standard acute toxicity assays using Daphnia, although Brachionus plycatilis larvae were more sensitive to these pyrethroid insecticides than T. platyurus. Analysis of 24 h LC(50) values of these pyrethroids, determined by static bioassays, revealed that the rank order of toxicity was: permethrin相似文献   

Multi-biomarker responses in green mussels exposed to PFCs: effects at molecular,cellular, and physiological levels

Perfluorinated chemicals (PFCs) are extremely persistent and have been found extensively in the environment and wildlife. Oceans are the final sink for many persistent organic pollutants (POPs) including PFCs. However, to date, there has been a lack of studies that investigated the environmental consequences of PFCs on marine organisms. To fill in this gap, environmental toxicity of two dominant PFCs, perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), was examined in a sentinel species, green mussel Perna viridis, using a series of biomarkers corresponding to different biological levels (molecular, cellular, and physiological). Correlations among these biomarkers were also investigated. The results showed that the tested compounds can induce a series adverse effect at different biological levels, including oxidative stress, DNA damage, membrane instability, suppressed filtration rate, and reduced body weight. Correlation analysis revealed that excess production of reactive oxygen species could be the major toxic pathway. An indirect mode of toxic action was also explored where adverse impacts could be secondary effects of PFC exposure. The joint analysis of biomarkers from multiple biological levels resulted in a comprehensive understanding of how PFC exposure can influence the health of organisms. The correlations of these biomarkers also provided a new perspective of the ecological consequences of PFCs.     

A review on the application of microbial toxicity tests for deriving sediment quality guidelines

The results of microbial toxicity tests are needed for the risk assessment of polluted sediments. In comparison with animals the anaerobic microorganisms are more tolerant to natural sediment conditions whereas they are more sensitive for a number of specific pollutants. Microbial toxicity tests from a literature search were classified in seven categories. Category A, B and C use polluted sediments and are applied for sediment monitoring. In category D, a pure chemical is added and the organisms and the test conditions were derived from sediment. Therefore this category can be used for setting sediment quality guidelines which protect sediment functions for the toxic effects of chemicals. In category E, organisms from a polluted site are separated from the sediment and are tested with pure chemicals. Organisms from a more polluted site can be more tolerant to a local pollutant. This is called pollution-induced community tolerance and can be used as evidence for the occurrence of toxic effects in a specific sediment. In category F pure chemicals are tested with a pure culture of microorganisms under sediment conditions. The results of category F tests can be combined with single species tests with animals and plants to obtain sediment quality guidelines sufficient for species protection. This can be compared with the sediment quality guidelines which protect sediment functions. When one of these quality guidelines is exceeded for a compound at a specific location a category E test can be used to determine whether the compound shows toxic effects in that sediment.     

The effect of soil composition and hydration on the bioavailability and toxicity of cadmium to hibernating juvenile American toads (Bufo americanus)

The soil ecotoxicology literature has focused primarily on a few major taxa, to the neglect of other fossorial organisms such as amphibians. We selected cadmium (Cd) and the American toad (Bufo americanus) as a model contaminant and biological species to assess the impact of soil contamination on amphibian hibernation survival and post-hibernation condition. Soil sand composition (50, 70, 90%) and hydration (100, 150% water holding capacity (WHC)) were manipulated in addition to Cd concentration (0, 56, 165, 483 microg/g) to determine whether these soil properties affect toxicity. Soil Cd concentration significantly reduced survival and locomotor performance, and was correlated negatively with percent mass loss and positively with whole body Cd concentration. Higher sand content resulted in less mass loss and greater Cd uptake. Toads that were hibernated in 50% sand hydrated to 100% WHC had higher survival, less mass loss, and better sprint performance than those hibernated in 50% sand, 150% WHC. This study demonstrates that concentrations of Cd found in soil at highly contaminated sites can be bioaccumulated by hibernating amphibians and may reduce fitness. Differences in microhabitat use may cause species to vary in their exposure and susceptibility to soil contamination. The toxicity of Cd to amphibians could be greater in natural systems where there are multiple stressors and fluctuations in environmental variables.     

Growth assays with mixed cultures of cyanobacteria and algae assessed by in vivo fluorescence: One step closer to real ecosystems?

A growth toxicity assay with mixed cultures of cyanobacteria and algae using in vivo fluorescence is presented. Test organisms (the green alga Pseudokirchneriella subcapitata and the cyanobacterium Aphanothece clathrata) growing alone and in a mixture were exposed to selected chemicals. P. subcapitata featured a higher sensitivity to toxicants in the presence of A. clathrata compared to the single species assay. On the other hand, growth of a cyanobacterium was not affected by the presence or absence of the green alga. The proposed method seems to be suitable for pre-screening studies of toxicants (algistatic agents, herbicides) applied into the aquatic environment and for the assessment of their impact on natural phytoplankton communities.     

Toxicity of chlorophenols to Pseudokirchneriella subcapitata under air-tight test environment

A closed-system algal toxicity test with no headspace was applied to evaluate the toxicity of chlorophenols to Pseudokirchneriella subcapitata. The dissolved oxygen production and the growth rate based on cell density were the response endpoints. Phenol and seven chlorophenols were tested using the above test technique. Median effective concentrations (EC50) range from 0.004 to 25.93 mg/l (based on DO production) and 0.0134 to 20.90 mg/l (based on growth rate). No-observed-effect concentration (NOEC) is within the range of 0.001-8.19 mg/l. In general, growth rate is a more sensitive response endpoint than the oxygen production, except for the case of pentachlorophenol. However, the differences in sensitivity between the two parameters were marginal. Furthermore, quantitative structure-activity relationships (QSAR's) based on the n-octanol/water partition coefficient (log P) and the acid dissociation constant (pK(a)) values were established with R(2) ranged from 0.90 to 0.96. From literature data also based on P. subcapitata, the new test method is 1.65-108 times more sensitive than the conventional algal batch tests. A completely different relative-sensitivity relationship among various aquatic organisms was thus observed. The results of this study indicate that the toxicity data of volatile organic chemicals derived by conventional algal toxicity tests may severely underestimate the impact of these toxicants. Our results show that alga is very sensitive to chlorophenols compared to other aquatic organisms such as the luminescent bacteria (the Microtox test), Daphnia magna, and rainbow trout.     

Statistical evaluation of chronic toxicity data on aquatic organisms for the hazard identification: the chemicals toxicity distribution approach

Presently, in the Globally Harmonised System of Classification and Labelling of Chemicals the classification of substances for long-term effects to aquatic life is based on acute toxicity in combination with degradation and/or bioaccumulation potential. Recently an OECD Working Group was created to develop the classification scheme to accommodate chronic toxicity data related to aquatic organisms for assigning a chronic hazard category. This study focuses on a new approach for setting chronic toxicity cut-off values based on Chemicals Toxicity Distributions (CTDs). A CTD is obtained through statistical fitting of the data used by regulatory bodies for setting hazard-based classifications. The CTDs were made using the lowest aquatic NOEC value of each chemical. A review of different toxicological sources reporting acute aquatic toxicities was carried out. Initially, the data were arranged according to the specific source and distributions for key taxonomic groups (i.e. fishes, crustaceans and algae) were evaluated separately. In most cases, no significant departures from normality were observed. Thereafter, a compiled database containing >900 values was developed and the CTDs were constructed for each taxonomic group. Significant deviation from normality (P < 0.05) was observed in the fishes and crustaceans' CTDs. However, this deviation was apparently produced by the presence of only seven values with NOECs <1 x 10(-5) mg l(-1), while high correlation between the data and the normal scores (r-values>or= 0.989) indicated that the data were samples from normal distributions. From these observations, potential cut-off values would allow quantitative estimations of the percentage of chemicals falling into each specific category. This approach results in a simple classification hazard scheme where most chemicals are covered in one of the categories, allowing a clear distribution of the chemicals among three categories for chronic toxicity.     

Flow cytometry assessment of cytotoxicity and reactive oxygen species generation by single and binary mixtures of cadmium, zinc and copper on populations of the ciliated protozoan Tetrahymena thermophila

In the present study, we have assessed by flow cytometry, the cytotoxicity of the heavy metals Cd, Zn and Cu on populations of the ciliated protozoan Tetrahymena thermophila. The obtained LC(50) for these metals was estimated as 0.195mgCdl(-1), 3.58mgZnl(-1) and 0.47mgCul(-1), respectively. As a result, the toxicity rank for this eukaryotic microorganism is Cd>Cu>Zn. Using the same methodology and the Concentration Addition approach, the toxicity of binary mixtures of these metals was evaluated in order to detect the type of interaction between these metals. Results indicated that antagonism is the predominant interaction but it can change to additivity or even to synergism at high metal concentrations. Besides, the concentration ratio between metals plays also a crucial role in determining the type of metallic interaction, at least in Tetrahymena. Cytotoxicity data from single and bimetallic mixtures have been compared with those from selected microalgae, other species of ciliates, fish and mammalian cell lines and metazoan. By other hand, we have detected the mitochondrial generation of peroxides induced by both single and binary treatments with Cd, Zn and Cu on populations of Tetrahymena, using the specific fluorophore dyhidrorhodamine. The nature and concentrations of metal as well as the metallic ratio were important factors in reactive oxygen species production. All results found in T. thermophila are compared with previous reports in other organisms and, some explanations and hypothesis to support results are given, including the involvement of metallothioneins as antioxidants and their role in the binding of metal cations.     

Relative sensitivity of one freshwater and two marine acute toxicity tests as determined by testing 30 offshore E & P chemicals

Acute toxicity of 30 offshore E & P (Exploration and Production) chemicals was measured using the three standard test organisms Daphnia magna (freshwater cladoceran), Acartia tonsa (marine copepod) and Skeletonema costatum (marine diatom alga). Test chemicals included 20 water-soluble and 10 (partially) non-soluble products. For 22 out of the 30 chemicals, the difference in sensitivity between the three tests varied within one order of magnitude. A very good correlation was found between the two marine tests (r = 0.96, P < 0.01, n = 30), and a correlation coefficient of r = 0.78 (P < 0.01, n = 30) was found between D. magna and both A. tonsa and S. costatum, individually. When the comparison of D. magna and A. tonsa sensitivity was based only on the water-soluble chemicals, a significantly higher correlation was obtained (r = 0.84, n = 20), indicating that the sample preparation method used for the (partially) non-soluble chemicals (the water accommodated fraction (WAF) method) induces additional variation between tests performed with different test media. (Partially) non-soluble chemicals are characterised by phase separation or precipitation at the concentrations used for testing. In a WAF-based test, each test concentration/exposure level is prepared separately, and following mixing and separation, only the water phase is used for testing. Toxicity is related to the amount of substance originally added to the mixing vessels. For 25 of the 30 chemicals, D. magna was found to be less sensitive than the marine copepod by a factor >2. The generally higher sensitivity of the marine toxicity tests compared to the Daphnia test emphasise the importance of using marine data for environmental hazard classification as well as for environmental risk assessment purposes.     

Comparing the sensitivity of soil invertebrates to pesticides with that of Eisenia fetida

The sole routine testing of the standard earthworm Eisenia fetida for the terrestrial risk assessment of pesticides has been under much debate since other soil invertebrates may be more sensitive than this standard test species. However, the very low availability of laboratory toxicity data for taxa other than E. fetida has greatly hampered sensitivity comparisons. In the present study, the relative tolerance (T_rel) approach was used to enable comparing toxicity thresholds obtained from the US-EPA ECOTOX database, for main terrestrial taxonomic groups and pesticidal types of action (insecticides, fungicides, herbicides, and other) separately. Analyses confirmed previously reported lower and higher sensitivity of collembolans to fungicides and insecticides, respectively. However, various other discrepancies in susceptibility relative to E. fetida were encountered as indicated by species sensitivity distributions and/or calculated 95% confidence intervals of T_rel values. Arachnids and isopods were found to be more sensitive to insecticides, and nematodes to fungicides, as compared to E. fetida. Implications of study findings for the terrestrial risk assessment of pesticides are discussed.     

Complex biological responses to the experimental acidification of Little Rock Lake, Wisconsin, USA

Acidification can affect aquatic organisms directly through hydrogen ion toxicity, and indirectly through disrupted food web dynamics and altered abiotic conditions. Field populations from selected taxa were studied during the Little Rock Lake whole-basin acidification experiment to illustrate patterns whose timing suggests direct (i.e. immediate) or indirect (i.e. delayed or non-uniform) responses to pH change. As the treatment basin was acidified to pH 5.6, 5.2 and 4.7, immediate changes consistent with a direct pH response were observed for species representing several trophic levels. For other taxa (e.g. littoral invertebrates associated with filamentous algal mats, several species of pelagic zooplankton), indirect mechanisms induced by food web changes were more likely explanations for abundance patterns. The results presented here suggest that the responses of aquatic ecosystems to acidification involve a complex interplay between direct pH effects and subsequent indirect interactions.     

Studies on lethal concentrations and toxicity stress of some xenobiotics on aquatic organisms

Three widely used xenobiotics pentachlorophenol (PCP), 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-chloro-2,6-diethyl-N-(butoxymethyl) acetanilide (Butachlor) are evaluated for acute toxicity and stress behavior on freshwater fish (Heteropneustes fossilis, Clarias batrachus, Channa punctatus) and mosquito larvae (Culex pipiens fatigans). The experiment was carried out by medium treatment using intermittent flow-through system. Median lethal concentrations (LC50) were calculated by probit analysis. The LC50 values and 95% confidence intervals showed variable range for tested chemicals. Mosquito larvae generally appeared resistant than fish, while H. fossilis was found to be most sensitive. Stress signs in the form of behavioral changes are also observed. Both types of organisms are recommended as good bioindicator for the risk assessment of aquatic environment due to chemicals tested.     

Assessment of aquatic experimental versus predicted and extrapolated chronic toxicity data of four structural analogues

The present study was developed to assess the chronic toxicity predictions and extrapolations for a set of chlorinated anilines (aniline (AN), 4-chloroaniline (CA), 3,5-dichloroaniline (DCA) and 2,3,4-trichloroaniline (TCA)). Daphnia magna 21 d chronic experimental data was compared to the chronic toxicity predictions made by the US EPA ECOSAR QSAR tools and to acute-to-chronic extrapolations. Additionally, Species Sensitivity Distributions (SSDs) were constructed to assess the chronic toxicity variability among different species and to investigate the acute versus chronic toxicity in a multi-species context.Since chlorinated anilines are structural analogues with a designated polar narcotic mode of action, similar toxicity responses were assumed. However, rather large interchemical and interspecies differences in toxicity were observed. Compared to the other three test compounds, TCA exposure had a significantly larger impact on growth and reproduction of D. magna. Furthermore, this study illustrated that QSARs or a fixed ACR are not able to account for these interchemical and interspecies differences. Consequently, ECOSAR was found to be inadequate to predict the chronic toxicity of the anilines and the use of a fixed ACR (of 10) led to under of certain species. The experimental ACRs determined in D. magna were substantially different among the four aromatic amines (ACR of 32 for AN, 16.9 for CA, 5.7 for DCA and 60.8 for TCA). Furthermore, the SSDs illustrated that Danio rerio was rather insensitive to AN in comparison to another fish species, Phimphales promelas. It was therefore suggested that available toxicity data should be used in an integrative multi-species way, rather than using individual-based toxicity extrapolations. In this way, a relevant overview of the differences in species sensitivity is given, which in turn can serve as the basis for acute to chronic extrapolations.     

A cross-taxa survey of organochlorine pesticide contamination in a Costa Rican wildland

Amphibians, turtles, birds (mostly passerines) and mice collected from a conservation area in northwestern Costa Rica were analyzed for organochlorine (OC) pesticide contamination. Six of 39 amphibians (three of eight species), three of six turtles (two species), one of eight mice (one species) and 19 of 55 birds (five of seven species) contained OCs at levels up to 580 ng/g. The most frequently detected compound in 23 of 108 organisms was p,p'DDE. Dieldrin, delta-BHC, heptachlor, p,p'DDD, and endosulfan II were each found in at least four organisms, while eight other OCs were found in at least one organism. The presence of OCs in taxa from the conservation area indicates the likelihood of long-distance transport of such compounds through the atmosphere.