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The ostracod Cypris subglobosa Sowerby, 1840 static bioassay test on the basis of a 48h of 50% of immobilization (EC(50)) has been used to measure the toxicity of 36 metals and metalloids and 12 reference toxicants. Among the 36 metals and metalloids, osmium (Os) was found to be the most toxic in the test while boron (B), the least toxic. The EC(50) values of this study revealed positive linear relationship with the established test models of cladoceran (Daphnia magna), sludge worm (Tubifex tubifex), chironomid larvae (Chironomus tentans), protozoan (Tetrahymena pyriformis), fathead minnow (Pimephales promelas), bluegill sunfish (Lepomis macrochirus), and aquatic macrophyte duckweed (Lemna minor). Correlation coefficients (r(2)) for 17 physicochemical properties of metals or metal ions and EC(50)s (as pM) were examined by linear regression analysis. The electronegativity, ionization potential, melting point, solubility product of metal sulfides (pK(sp)), softness parameter and some other physicochemical characteristics were significantly correlated with EC(50)s of metals to C. subglobosa. The reproducibility of toxicity test was determined using 12 reference toxicants. The coefficient of variability of the EC(50)s ranged from 6.95% to 55.37% and variability was comparable to that noticed for D. magna and other aquatic test models. The study demonstrated the need to include crustacean ostracods in a battery of biotests to detect the presence of hazardous chemicals in soils, sewage sludges, sediments and aquatic systems.

New products of nanotechnologies, including nanoparticles, need to be assessed according to their biological reactivity and toxic potential. Given the large number of diverse nanomaterials, a tiered approach is favoured. The aim of our work presented here is to elaborate an in vivo assay with terrestrial invertebrates (Porcellio scaber), which could serve as a first step of hazard identification of nanoparticles. We adapted the widely used acridine orange/ethidium bromide (AO/EB) assay to be applicable for cell membrane stability assessment of entire organ where the animal was exposed in vivo. The digestive glands (hepatopancreas) of terrestrial isopods were taken as a model test system. The assay was validated with Cu(NO(3))(2) and surfactants. The results showed that all tested nanoparticles, i.e. nanosized TiO(2), nanosized ZnO and fullerenes (C(60)) have cell membrane destabilization potential. As expected, C(60) is the most biologically potent. The AO/EB in vivo assay proved to be fast because response is recorded after 30 min of exposure, relatively simple because digestive glands are inspected immediately after isolation from exposed animals and promising approach because different types of nanoparticles could be tested for their biological potential. This assay provides data for the identification of hazardous potential of nanoparticles before subsequent steps in a tiered approach are decided.

The aim of this study was to evaluate the applicability of three bioassays representing multiple trophic levels, for the preliminary ecotoxicological screening of sediments from sites contaminated by mining activities. Of the bioassays used in this study, the ostracod test was the most responsive. Vibrio fischeri luminescence inhibition assay was less sensitive to the toxicants in the sediments than the phytotoxicity assays. The general trend observed was an increase in toxicity values measured by the bioassays with increasing metal mobilization in sediment samples. Therefore, the test battery can be used as a rapid and sensitive tool to evaluate the heavy metal contamination in sediments.

Questioning the likelihood that populations adapt to contamination is critical for ecotoxicological risk assessment. The appraisal of genetic variance in chemical sensitivities within populations is currently used to evaluate a priori this evolutionary potential. Nevertheless, conclusions from this approach are questionable since non-additive genetic components in chemical tolerance could limit the response of such complex phenotypic traits to selection. Coupling quantitative genetics with ecotoxicology, this study illustrates how the comparison between cadmium sensitivities among Gammarus siblings enabled discrimination between genetic variance components in chemical tolerance. The results revealed that, whereas genetically determined differences in lethal tolerance exist within the studied population, such differences were not significantly heritable since genetic variance mainly relied on non-additive components. Therefore the potential for genetic adaptation to acute Cd stress appeared to be weak. These outcomes are discussed in regard to previous findings for asexual daphnids, which suggest a strong potency of genetic adaptation to environmental contamination, but which contrast with compiled field observations where adaptation is not the rule. Hereafter, we formulate the reconciling hypothesis of a widespread weakness of additive components in tolerance to contaminants, which needs to be further tested to gain insight into the question of the likelihood of adaptation to contamination.

Several biomarkers indicative of stress were characterised in the crustaceans Aristeus antennatus and Nephrops norvegicus sampled off the Barcelona coast (NW Mediterranean). The biomarkers selected were cholinesterase (ChE) activities in muscle; and catalase, glutathione reductase (GR), total glutathione peroxidase (t-GPX), DT-diaphorase (DT-D), glutathione S-transferases (GSTs) and carboxylesterases (CbEs) in hepatopancreas tissue. Lipid peroxidation (LP) levels and total protein yield (PY) were also determined in muscle and hepatopancreas tissues. The activities and levels are discussed in relation to species and season, and differences in these two factors were observed for most biomarkers. AChEs and pseudocholinesterases were present in the muscles of both crustaceans. Catalase and GST activities were higher in N. norvegicus, whereas GR and t-GPX activities varied according to the season. Hepatic CbE activities were similar in the two crustaceans, whereas LP levels and PY were different between species. Seasonality and species particularities are factors to consider when these crustaceans are used as sentinels.

Cerium dioxide nanoparticles (CeO2 NPs) are increasingly being used as a catalyst in the automotive industry. Consequently, increasing amounts of CeO2 NPs are expected to enter the environment where their fate in and potential impacts are unknown. In this paper we describe the fate and effects of CeO2 NPs of three different sizes (14, 20, and 29 nm) in aquatic toxicity tests. In each standard test medium (pH 7.4) the CeO2 nanoparticles aggregated (mean aggregate size approximately 400 nm). Four test organisms covering three different trophic levels were investigated, i.e., the unicellular green alga Pseudokirchneriella subcapitata, two crustaceans: Daphnia magna and Thamnocephalus platyurus, and embryos of Danio rerio. No acute toxicity was observed for the two crustaceans and D. rerio embryos, up to test concentrations of 1000, 5000, and 200 mg/L, respectively. In contrast, significant chronic toxicity to P. subcapitata with 10% effect concentrations (EC10s) between 2.6 and 5.4 mg/L was observed. Food shortage resulted in chronic toxicity to D. magna, for wich EC10s of > or = 8.8 and < or = 20.0 mg/L were established. Chronic toxicity was found to increase with decreasing nominal particle diameter and the difference in toxicity could be explained by the difference in surface area. Using the data set, PNEC(aquatic)S > or = 0.052 and < or = 0.108 mg/L were derived. Further experiments were performed to explain the observed toxicity to the most sensitive organism, i.e., P. subcapitata. Toxicity could not be related to a direct effect of dissolved Ce or CeO2 NP uptake or adsorption, nor to an indirect effect of nutrient depletion (by sorption to NPs) or physical light restriction (through shading by the NPs). However, observed clustering of NPs around algal cells may locally cause a direct or indirect effect.

Few studies have considered the environmental impacts of impurities and byproducts associated with low-efficiency nanomanufacturing processes. Here, we study the composition and aquatic toxicity of low-purity, as-produced fullerenes (C60) and metallofullerene waste solids, both of which were generated via arc-discharge synthesis. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and inductively coupled plasma mass spectroscopy (ICP-MS) were used to characterize the metals composition of the solid test materials and of aqueous leachates prepared by mixing test materials with waters of varying pH, hardness, and salinity. The aquatic toxicity of the leachates was determined using U.S. Environmental Protection Agency recommended aquatic bioassay protocols with two standard test organisms-Pimephales promelas and Ceriodaphnia dubia. Results indicated that metals associated with the solid test materials became mobilized in our test system upon interaction with waters of circumneutral pH and reached concentrations sufficient to induce toxicity in both test species. Acute (48 h) LC50 values for P. promelas and C. dubia exposed to leachates prepared from metallofullerene waste solids were 54 and 5% (as % leachate in diluent), respectively. Toxicity was eliminated after adding the chelator EDTA to the leachates, implicating divalent transition metals as the toxicity source. Our results demonstrate the aquatic toxicity of metals mobilized from products and byproducts of nanomanufacturing, and they emphasize the need for a global review of nanomanufacturing wastes and low-purity products.

In the present study a toxicity evaluation (Heterocypris incongruens, OstracodToxKit FTM Test) was carried out for ten municipal sewage sludges in relation to polycyclic aromatic hydrocarbon (PAH) contents in these sludges. PAHs content in the sewage sludges was determined by a vigorous extraction method and solid phase extraction with Tenax-TA. The main aim of the evaluation was establishing whether it was possible to determine the negative influence of PAHs in the sewage sludges on H. incongruens mortality and growth inhibition using the Tenax-TA method. H. inconguens showed increased growth inhibition and mortality when exposed to all sewage sludges. Significant relationships were noted between the content of some Tenax-TA PAH fractions and the total organic carbon content, cation exchange capacity and concentration of Ca(2+) ions. The toxicity was proportional to Tenax-TA concentrations and was not governed by the total concentration found in the sewage sludge.

Antimony is widespread in aquatic environment. Trivalent forms of antimony are known to be more toxic than other chemical species of antimony. In the present study, antimony potassium tartrate (APT), the trivalent inorganic forms of antimony, was selected as a test antimony compound due to its high water solubility. The effects of antimony on Japanese medaka (Oryzias latipes), planktonic crustacea (Moina macrocopa and Simocephalus mixtus), and green algae (Pseudokirchneriella subcapitata) were evaluated. Larval survival and the embryonic development were measured for fish assay. APT was less toxic to larval medaka (24-h LC50, 261; 48-h LC50, 238 mg L(-1)). Simocephalus mixtus was killed by very low concentrations of APT (24-h LC50, 4.92 mg L(-1)), and antimony was also toxic to Moina macrocopa (24-h LC50, 12.83 mg L(-1)). Toxicities of APT to S. mixtus and Moina macrocopa were about 50 and 20 times more toxic to Oryzias latipes larvae, respectively, in terms of 24-h LC50 value. Growth inhibition of Pseudokirchneriella subcapitata was observed in the presence of APT (72-h EC50, 206 mg L(-1)). This study demonstrated that APT is more toxic to planktonic crustacea than fish and green algae, and planktonic crustacea appears a better indicator of antimony pollution in aquatic environment.

Farming of salmon has become a significant industry in many countries over the past two decades. A major challenge facing this sector is infestation of the salmon by sea lice. The main way of treating salmon for such infestations is the use of medicines such as organophosphates, pyrethrins, hydrogen peroxide or benzoylphenyl ureas. The use of these medicines in fish farms is, however, highly regulated due to concerns about contamination of the wider marine environment. In this paper we report the use of photochemically active biocides for the treatment of a marine copepod, which is a model of parasitic sea lice. Photochemical activation and subsequent photodegradation of PDAs may represent a controllable and environmentally benign option for control of these parasites or other pest organisms in aquaculture.

We investigated the effects of environmentally relevant concentrations of nonylphenol (NP) on survival, growth, sexual development and molting of the mysid Americamysis bahia (Crustacea: Mysidacea), including assay of 20-hydroxyecdysone (20E) levels. Seven-day-old mysids were exposed to NP concentrations of 0.3, 1, 3, 10 and 30 microg/L for 14 days. Among growth-related traits we assayed, an effect on body length was the most prominent, with the effects observed at concentrations as low as 1 microg/L NP. In addition, the total number of molting exposed to NP for 14 days was significantly decreased in the treatment groups at 10 or 30 microg/L relative to the controls. These results clearly indicate that subchronic exposure to environmentally relevant concentrations of NP affects growth of mysids. Furthermore, we investigated the effect of NP on production of 20E in female mysids during the molting period. Production of 20E in pre-molting mysids exposed to 30 microg/L of NP was lower than those in control groups, and exposure of female mysids to NP disrupted molting cycles. Taken together, the results suggest that environmentally relevant concentrations of NP can disrupt growth of A. bahia via inhibition of 20E levels and an associated delay in molting.

The main objective of this study was to evaluate the acute toxicity of raw, neutralized and physico-chemically treated and biologically treated effluent of herbal pharmaceutical industry. The acute toxicity test was determined using freshwater crustacean Ceriodaphnia dubia under laboratory conditions. LC(50) values for raw, neutralized and physico-chemically treated effluent for 12, 24, 36 and 48 h ranged between 3.0-4.5%, 3.9-10.8% and 22-28% respectively. It is evident from the results that physicochemical treatment reduced the toxicity by around 25% while biological treatment reduced the toxicity completely. Results subjected to statistical evaluation depicted regression coefficient of more than 0.9 indicating good correlation between the mortality rate and effluent concentrations.

General mortality (death rate, d) in natural populations of the crustacean zooplankton is calculated as difference between birth rate (b) and population growth rate (r). The mortality includes both predatory (consumptive) and non-predatory (non-consumptive), or "natural", deaths of individuals due to senescence, diseases and parasites, starvation, limiting physical and chemical factors of anthropogenic or natural origin. Modem methods of evaluation of non-predatory mortality of the plankton crustaceans, including direct method based on live/dead sorting by special staining of samples and measurements of sedimentation rate of dead individuals using a sedimentation trap are briefly characterized. Possible causes of non-predatory mortality of crustacean are examined based on different (mainly fresh) temperate water bodies. The possible causes are classified as: physical conditions including temperature, wind effects, ultraviolet radiation, water turbidity, current velocity; chemical conditions including concentration of dissolved oxygen, pH value, water toxicity of both anthropogenic (due to pollutant inflow) and natural (due to cyanobacterial bloom and ingestion of some toxic diatoms by copepods) origin; parasites and epibionts; bottom-up factors or food limitation including quantity and quality of food, the former as content of carbon (energy) and the latter as content of essential compounds in food. It is concluded that, for the populations of crustacean herbivorous zooplankton, the biotic factors appeared to be more important and more probable causes of non-predatory mortality than the abiotic ones, under conditions of non-acid water bodies of the temperate zone when the current speed is less than critical one (0.25 m/c) and in absence of the anthropogenic toxicants. These factors are primarily a food poor quality due to low content of phosphorus, nitrogen, polyunsaturated fatty acids of omega3 family and others, as well as microparasites causing infections and, to a lesser extent (just in blooming water bodies), natural toxicity of cyanobacteria. Non-optimal for the zooplankton physical and chemical factors, as causes of non-predatory mortality of plankton crustaceans, appeared to be less important because of their acting episodically in time locally in space, so the zooplankton is able to avoid their effects and to regenerate fast.

The aim of the present study was to determine the content of the bioaccessible fraction of polycyclic aromatic hydrocarbons (PAHs) in sewage sludges and composts by means of three techniques (solid phase extraction with Tenax-TA and non-exhaustive extraction with hydroxypropyl[beta]cyclodextrin and n-butanol) and at the same time to establish their influence on toxicity for Heterocypris incongruens (Ostracodtoxkit test) and Lepidium sativum (Phytotoxkit test). In the majority of cases sewage sludges negatively influenced on organisms. Generally, sewage sludge composting exerted a positive influence on phytotoxicity, whereas in the case of ecotoxicity a negative effect was noted. The content of the potentially bioaccessible PAHs fraction varied depending on the method applied. Composting usually lowered the content of the potentially bioaccessible fraction. Significant positive relationships were observed mainly between Tenax-TA extracted fraction of individual PAHs and growth inhibition of H. incongruens. Only negative correlations were noted in the case of phytotoxicity.

This study evaluated the median lethal concentration (LC50) and safe concentration of water-borne ammonia, phosphate and pH value on Physocypria kraepelini, a freshwater Ostracoda with a static renewal test system. The results indicated that the LC50 values of ammonia for P kraepelini were 1026.71, 859.98, 771.79 and 583.82 mg/L at 24, 48, 72 and 96 h exposure, respectively, and the safe concentration range of ammonia for the long-term survival of P. kraepelini was less than 58.38 mg/L. The safe range of pH value for the survival of P. kraepelini was from 6.59 to 7.61. P. kraepelini has a high tolerance to ammonia, phosphate and pH value which are the main environmental factors in the serious eutrophication water.

Recent studies have indicated the potential for dietborne metals as an important exposure pathway for metal toxicity in freshwater organisms. We conducted a study in which freshwater cladocerans (Ceriodaphnia dubia) were fed green algae (either Pseudokirchneriella subcapitata or Chlorella vulgaris) that were grown in Ag- or Cu-contaminated media. In one series of toxicity tests patterned after the U.S. Environmental Protection Agency's three-brood C. dubia chronic toxicity test, we exposed C. dubia to waterborne Ag or Cu while feeding them normal amounts of uncontaminated yeast-Cerophyll-trout chow (YCT) slurry and either algae grown in standard media or algae grown in standard media supplemented with Ag or Cu (added as AgNO3 or CuSO4 x 5H2O). These parallel tests demonstrated that dietborne metal did not contribute to survival or reproduction effects beyond the effects caused by waterborne metal alone. We also conducted dietborne-only toxicity tests patterned after two other recently published experimental designs in which (1) C. dubia were fed only metal-contaminated algae for 4 h, transferred to fresh water, and fed uncontaminated algae and YCT slurry for the duration of the three-brood test or (2) C. dubia were fed standard amounts of metal-contaminated algae and uncontaminated YCT slurry for the entire three-brood test. In contrast to previous studies, we did not find consistent dietborne metal toxicity or standard concentration-response relationships in those two experiments. Instead, among-experiment variation in intracellular partitioning of metals in the algae fed to the C. dubia, among-laboratory differences in experimental procedures, selective feeding by C. dubia to avoid metal-contaminated algae, an interaction between reproductive status of the C. dubia and dietborne metal concentration, or a combination of these might help explain the apparently inconsistent results.

A new series of asymmetric salicyl-, furanyl-, thienyl- and pyrrolyl-derived ONNO, NNNO, ONNS & NNNS donor antibacterial and antifungal Schiff-bases and their copper(II) and zinc(II) metal complexes have been synthesized and characterized. IR spectra indicated the ligands to act as quartdentate towards divalent metal ions via two azomethine-N, deprotonated-O of salicyl, furanyl-O, thienyl-S and/or pyrrolyl-N. The magnetic moments and electronic spectral data suggest octahedral geometry for Cu(II) and Zn(II) complexes. NMR spectral data of the ligands and their diamagnetic zinc(II) complexes well-define their proposed structures/geometries. Elemental analyses data of the ligands and metal complexes agree with their proposed structures/geometries. The synthesized ligands, along with their metal complexes were screened for their antibacterial activity against B. cereus, C. diphtheriae, E. coli, K. pneumoniae, P. mirabilis, P. aeruginosa, S. typhi, S. dysenteriae and S. aureus strains and for in-vitro antifungal activity against T. schoenleinii, C. glabrata, P. boydii, C. albicans, A. niger, M. canis and T. mentagrophytes. The results of these studies show the metal complexes to be more antibacterial/antifungal against one or more species as compared to the uncomplexed ligands. The brine shrimp bioassay was also carried out to study their in-vitro cytotoxic properties. Eight compounds, L(4), (1), (7), (8), (11), (17), (19) and (23) displayed potent cytotoxic activity with LD(50) = 1.445 x 10(- 3), 1.021 x 10(- 3), 7.478 x 10(- 4), 8.566 x 10(- 4), 1.028 x 10(- 3), 9.943 x 10(- 4), 8.730 x 10(- 4) and 1.124 x 10(- 3) M respectively, against Artemia salina.

The drainage of abandoned mines leads to several ecological problems, particularly the acidification of surface freshwater systems and heavy metal contamination. In order to study the possibility of using the behavioural early warning responses of Portuguese indigenous benthic invertebrates to detect an acute short-term pulse of Acid Mine Drainage (AMD), experiments with the Multispecies Freshwater Biomonitor MFB were performed and locomotion and ventilation were measured as endpoints. AMD was collected from the "São Domingos" mine (Southeast Portugal) and the following species were selected: Echinogammarus meridionalis (Pinkster, 1973), Hydropsyche pellucidula (Curtis, 1834) and Choroterpes picteti (Eaton, 1870). For simulating the pulsed exposure, AMD was added to river water where invertebrates were collected and pH was lowered until reaching 3.5. The effects of H+ and heavy metals were discriminated using HCl positive controls. In addition to behaviour, mortality was registered. E. meridionalis was the most sensitive species in terms of mortality and behavioural endpoints, followed by C. picteti and H. pellucidula. E. meridionalis early warning responses consisted of increased locomotion with subsequent increase in ventilation, whereas for C. picteti only an increase in locomotion was observed. H. pellucidula showed no early warning responses. This work demonstrates the suitableness of using benthic invertebrates' behavioural early warning responses for detecting spikes of pollutants like AMD.

A series of 15 previously reported N(4)-substituted isatin-3-thiosemicarbazones 3a-o has been screened for cytotoxic, antibacterial, antifungal and urease inhibitory activities. Compounds 3b, 3e and 3n proved to be active in cytotoxicity assay; 3e exhibited a high degree of cytotoxic activity (LD(50) = 1.10 x 10(-5) M). Compound 3h exhibited significant antibacterial activity against B. subtilis, whereas compounds 3a, 3k and 3l displayed significant antifungal activity against one or more fungal strains i.e. T. longifusus, A. flavus and M. canis. In human urease enzyme inhibition assay, compounds 3g, 3k and 3m proved to be the most potent inhibitors, exhibiting relatively pronounced inhibition of the enzyme. These compounds, being non-toxic, could be potential candidates for orally effective therapeutic agents to treat certain clinical conditions induced by bacterial ureases like H. pylori urease. This study presents the first example of inhibition of urease by isatin-thiosemicarbazones and as such provides a solid basis for further research on such compounds to develop more potent inhibitors.

Diuron and copper pyrithione (CuPT) are two substances that have been used worldwide as alternatives to tributyltin (TBT) in antifouling paints for the protection of ship hulls. In this study their toxicity against the brine shrimp Artemia franciscana is examined under several combinations of salinity and temperature using the LC(20), LC(50) and LC(80) values found for the 25 degrees C and 35 per thousand standard conditions. A significant interaction between temperature and salinity effects was observed for both chemicals. Decreasing temperature almost eliminated Diuron's toxicity, while a toxicity reduction was also observed for CuPT. Decreasing salinity decreased Diuron's toxicity, while for CuPT the effect of salinity was more complex. These two natural environmental parameters had a profound influence on the ecotoxicity of the two tested chemicals, and this highlights the importance of considering the implications of such factors when conducting ecological risk assessment.

Although eels are well known to contain toxins in the serum, their chemical properties have remained to be clarified for a long time. In this study, a proteinaceous toxin was purified from the serum of Japanese eel Anguilla japonica by anion-exchange HPLC, hydroxyapatite HPLC and gel filtration HPLC. The toxin was lethal to both mice and crabs; the LD(50) of the purified toxin against mice (intravenous injection) and crabs (injection into body cavity) were estimated to be 670 and 450 mug kg(-1), respectively. Chemical analysis data revealed that the toxin is a monomeric simple protein with a molecular mass of 100 kDa and an isoelectric point of 6.1. Three of the peptide fragments produced by digestion of the purified toxin with lysylendopeptidase were sequenced. However, a database search based on the determined partial amino acid sequence failed to find any proteins sharing homology with the A. japonica serum toxin.

Acute hazard classification based on selected microbiotests was proposed to assess and compare the toxicity of rivers including surface-water, sediment and soil from floodplains. No direct relationship between the classification of pollution for surface-water based on physical-chemical parameters and proposed acute hazard classification based on organisms' sensitivity was observed. The quality of water according to hazard classification was better than in the mandatory classification of pollution, with the domination of Class II (slight acute hazard). The samples of sediment and soil were more toxic and represented Class II or Class III (acute hazard). The results indicated a need to complete the mandatory monitoring of surface-water in rivers with biological monitoring with toxicity assessment of rivers including water, sediment and soil from floodplains based on acute hazard classification. This integral approach enables a complete evaluation of the toxicity of aquatic life together with an estimation of negative changes in river systems.

The objective of this work was to analyse zoobenthic assemblages in the coastal sector of the Río de La Plata, Argentina, after a petroleum spill. Sampling stations were located in representative sites of various landscapes. Structure, composition, physico-chemical parameters and seasonal changes were recorded in order to assess taxocenosis evolution during the period 1999-2003. Recovery signs were estimated by means of biotic indices and the presence of sensitive species. Tolerant species were dominant in heavily polluted sites, with low diversity and water quality values, according to the biotic indices used. In certain zones, sediment quality remains impoverished, with a visible oil film on the surface. However, during the last sampling, some points showed an increase in biotic indices, pointing to a slight improvement in environmental conditions.

In this paper, the toxicity of linear alkylbenzene sulfonate (LAS) was evaluated in the marine microalga Isochrysis galbana using data of growth inhibition toxicity tests at 96-h exposure time. Toxicity was examined in standard conditions and by means of the modification of two variables of the test media: (1) the dilution water and (2) the content of nutrients in the test medium. For this purpose, a total of 10 toxicity test were designed: five dilution waters, four natural marine waters and one synthetic seawater; each in two different nutritive conditions, saturated nutrient concentration (SC) by the addition of modified f/2 nutritive medium, and natural nutrient concentration (NC), i.e., without the addition of f/2. At threshold toxicity levels, the dilution waters used in the test and the nutrient concentrations did not affect the toxicity of LAS. At IC50 concentrations, the toxicity of LAS is influenced by both variables: under SC conditions, the toxic effect of LAS diminishes, obtaining in all the tests IC50 > 10 mg/L LAS. Under NC conditions, IC50 concentrations ranging between 3.15 and 9.26 mg/L LAS have been obtained.

The aim of the present study was to evaluate to what degree polycyclic aromatic hydrocarbon (PAH) determines sewage sludge toxicity in relation to Heterocypris incongruens. Six differing sewage sludges with increasing contents of polycyclic aromatic hydrocarbons were selected for the present study. As well as total PAH content, the content of the potentially bioavailable fraction was also determined in the sewage sludges using a method of mild-solvent extraction (with n-butanol). The PAH content was also calculated in the sewage sludge pore water by the equilibrium partitioning method. The total PAH content in the sewage sludges studied were in the range 3.60 to 27.95 mg kg(-1). The contribution of the n-butanol extracted fraction was in the range 38.7 to 75.4%. In the group of individual PAHs, 4- and 5-ring compounds had the highest content in the potentially bioavailable group. H. incongruens mortality in the range 6.7 to 100%, depending both on the sewage sludge and the dose applied. An increase of the sewage sludge dose usually resulted in an increase in toxicity. At the highest dose, a 100% mortality of H. incongruens was found in half of the sludges. The lowest dose, irrespective of the sludge type, caused over 40% growth inhibition. However, the results obtained did not allow for the establishing of an unambiguous relationship between various sludge toxicity levels and the content of potentially bio-available PAHs. In some cases only, the extraction using n-butanol explained the high difference in toxicity despite a slight differentiation in the PAH content.

Interactions of herbicides and natural environmental stressors such as pH and food availability are poorly understood. We tested a chemical formulation of triclopyr (Release) at environmentally relevant test concentrations (0.25 and 0.50 mg L(-1)) in combination with two levels of pH (pH 5.5 and 7.5), and two levels of food availability (high and low). Population level effects of each stressor alone and in combination with the others were investigated using Simocephalus vetulus, a zooplankton species, and Rana pipiens tadpoles (Gosner stage 25), both common to forest ponds and wetlands. Herbicide treatments resulted in significant decreases in survival of both test species as well as reproduction and development time for S. vetulus at levels 5-10x below predicted worst case environmental concentrations (2.6 mg L(-1)). This laboratory study demonstrates a probable risk of toxic effects of Release herbicide which may be significantly increased by low food availability and by low pH at environmentally relevant concentrations.

In this study, the speciation of arsenic (As) and antimony (Sb) across a water-sediment interface and the formation of mono-, di-, and trimethylated species overtime in a microfiltered pore water solution were examined. We used an experimental technique, known as the sediment or fauna incubation experiment (SOFIE), which enables the determination of chemical speciation across redox zones in undisturbed systems. Five different incubation experiments were run: Over a 76 day incubation period, pore water was sampled and speciated 5 times. These experiments revealed the complete methylated species pattern for arsenic and antimony in the microfiltered sediment pore water. This constitutes the first report of methylated As and Sb species in a true pore water solution of sediments. Predominant organic species were dimethylantimony (DMSb up to 2.7 microg/L) and dimethylarsenic (DMAs up to 4.3 microg/L) followed by monomethylated species (MMAs and MMSb). These data (i) indicate that methylation significantly influences the translocation of As and Sb in sediments, (ii) demonstrate good agreement between the occurrence of methylantimony and the occurrence of methylarsenic in the pore water, (iii) reveal that As transformation in sediments is faster than Sb transformation but is more susceptible to disturbances from acidification, and (iv) regarding the translocation of these elements and antimony in particular, methylation is clearly a relevant, and perhaps as yet underestimated, factor.

The ability of anthropogenic chemicals to cause reproductive disorders has been the focus of toxicologists for many years. Whilst the focus of endocrine disrupting chemicals has mainly been associated with vertebrate groups, there have been continued calls for more research on the invertebrates. Surprisingly, within the Crustacea, many studies have focussed on female or growth/moulting related endpoints despite many of the vertebrate studies highlighting male related effects such as abnormal male reproductive development. Furthermore, a large number of the invertebrate studies have focussed on vertebrate estrogens or their mimics. Considering the biology of the crustacean endocrine systems, this paper shall argue that unlike the vertebrates, it is a lot more difficult to feminise a crustacean than it is to de-masculinise one. Consequently, crustacean toxicologists, by following the tact of vertebrate biologists, may have been trying to address the right questions, but in the wrong way. Studies have shown that intersexuality in crustaceans may arise through the masculinisation of heterogametic (WZ) females or the de-masculinisation of males through aberrations in male androgenic gland activity. It is recommended that the focus be put on understanding the mechanisms of sex determination in Crustacea, and the expression of male secondary sexual characteristics at the molecular, biochemical and physiological level are fully explored so that appropriate assessments can be made as to whether sexual endocrine disruption is occurring in this ecologically important group.

Two new modified hexacyclopeptides, aerucyclamides A and B, were isolated from the toxic freshwater cyanobacterium Microcystis aeruginosa PCC 7806. The constitution was assigned by spectroscopic methods, and the configuration determined by chemical degradation and analysis by Marfey's method combined with chemical synthesis. Synthetic aerucyclamide B was obtained through oxidation of aerucyclamide A (MnO2, benzene). The aerucyclamides were found to be toxic to the freshwater crustacean Thamnocephalus platyurus, exhibiting LC50 values for congeners A and B of 30.5 and 33.8 microM, respectively.

Arsenic is a proven carcinogen often found at high concentrations in association with gold and other heavy metals. The freshwater yabby, Cherax destructor Clark (Decapoda, Parastacidae), is a ubiquitous species native to Australia's central and eastern regions, with a growing international commercial market. However, in this region of Australia, yabby farmers often harvest organisms from old mine tailings dams with elevated environmental arsenic levels. Yabbies exposed to elevated environmental arsenic were found to accumulate and store as much as 100 microg/g arsenic in their tissues. The accumulation is proportional to the concentration of arsenic in the sediment and is high enough to be of concern for people who eat the yabbies. A comparison of arsenic levels in wild and lab-fed animals also was performed. Although there was no significant difference in the level of arsenic in the various organs of the wild animals, the animals purchased from a yabby farm showed a significantly higher arsenic concentration in their hepatopancreas (3.7 +/- 0.9 microg/g) compared to other organs (0.6-1.8 microg/g). Furthermore, after a 40-d exposure to food containing 200 to 300 microg/g inorganic arsenic, arsenate (As[V])-exposed animals showed a significant increase in tissue-specific arsenic accumulation, whereas arsenite (As[III])-exposed animals showed a lower, nonsignificant increase in As uptake, primarily in the hepatopancreas. These results have important implications for yabby growers and consumers alike.

In the present study the induction of metallothioneins (MTs) and its relation to cytosolic metal concentrations (Zn, Cu and Cd) in the euryhaline crustacean Neomysis integer exposed to Cd at different salinities was studied. N. integer was exposed to the same free cadmium ion activity of 5.74 x 10(-9) mol l(-1) (i.e. 1/5 of the 96 h LC(50) value expressed as cadmium activity) in hypo-osmotic (5 psu), isosmotic (16 psu) and hyper-osmotic media (25 psu) for 7 days. In this way, the effect of salinity on cadmium speciation was eliminated and therefore the physiological effect of salinity on Cd accumulation and MT induction could be studied. The accumulation of cytosolic Cd in N. integer changed with salinity from 1.11+/-0.05 micromol l(-1) at 5 psu up to 1.43+/-0.17 micromol l(-1) at 25 psu. This could indicate that the physiological response of euryhaline estuarine invertebrates like N. integer to salinity changes can influence the rate of trace metal uptake from solution. While the salinity changes did not cause significant differences in cytosolic Zn concentrations (mean value of all tested salinities: 34.4+/-2.8 micromol l(-1)), an inverse relationship between salinity and cytosolic Cu concentration was observed. The highest concentration of 15.7+/-2.3 micromol Cul(-1) was determined at 5 psu and the lowest 10.9+/-1.4 micromol Cul(-1) at 25 psu. This could point to a possible relationship between the copper concentration and the hemocyanin metabolism in N. integer. This is the first time that differential pulse voltammetry method was applied to MT assays with N. integer. Although the exposure to Cd resulted in a higher Cd cytosolic concentration, no subsequent MT increase was detected. The significant positive correlation between MT levels and cytosolic Cu concentrations (Spearman correlation coefficient r(s)=0.356, p=0.009) implies a strong relationship between MT and Cu in N. integer.

In the present report, the successful application of a Weight of evidence approach (WOE) to sediment quality assessment during a four year impact period following an oil spill is discussed. The study assesses the sediment quality on the Galician Coast (NW Spain) which was impacted by an accidental spill associated with the sinking of the tanker Prestige (2002). The assessment is based on three lines of evidence: physicochemical characterization of the sediments; determination of acute toxicity by conducting sediment toxicity tests and benthic alteration including taxonomic identifications along with community descriptive statistics. The data obtained were integrated using a WOE approach by means of two different methodologies: multivariate analysis and ANOVA-based pie charts. Results confirm that PAHs related to the Prestige oil spill are the main contaminant associated with biological effects in the area which has since recovered from the initial acute impact. Also, the WOE allowed the identification of metal contamination not previously described in the area responsible for toxicity in sediments analyzed. In addition, the methodology proposed to link the 3 lines of evidence results shows the use for the first time of an objective indice based on factor analysis which allows pollution of the sediments studied to be qualitatively and quantitatively evaluated while demonstrating the WOE approach to be recommendable in monitoring environmental quality.

Surface soils were collected at remote, urban and industrial sites in the Southern of Italy in order to evaluate PAH concentrations and assess the toxic effects by a battery of ecotoxicological tests. The tests were performed on whole soils and on both organic and aqueous extracts. Further goal of this study was to integrate the results coming from each test and matrix in a synthetic toxicity index. The highest summation sigmaPAH concentrations were measured at the industrial soil, although this one did not show an high ecotoxicological risk. Among the performed tests, the phytotoxicity tests showed the highest sensitivity. For whole soil, the worst case always has been represented by test through bacteria. Our results could represent the first step toward the selection of a proper battery to characterize the soil ecotoxicological risk.

The purpose of this paper is to present a new risk-based approach developed by Environment Canada for ranking pesticides and their potential risk to aquatic life. These rankings are compared to those generated using a more traditional score-based approach. Two hundred and twelve active ingredients registered in Canada for use in agricultural field crops were included in this assessment. For each major aquatic taxon assessed (fish, insects, crustaceans, algae, and macrophytes), risk was calculated by dividing the 96-h estimated environmental concentration (modeled using parameters such as the application rate and method as well as physicochemical properties) by HC5 values (obtained through calculations of species sensitivity distribution-based toxicity endpoints). The traditional approach assigned scores based on toxicity endpoints in standard test species as well as physicochemical properties associated with the potential for aquatic contamination. A number of similarities were observed between the rankings but also notable differences. Only 22 active ingredients were common to the top 50 ranking positions from both approaches. The main reasons that accounted for the discrepancies between both rankings were the choice of toxicity endpoints, whether based on single or multiple species; the taxonomic breadth of retained data; the use of scores versus risk quotients; and the choices made in situations where multiple data points were available. We conclude that a risk-based approach that considers a broad representation of species toxicity data and estimates of runoff and drift concentration in receiving aquatic systems (even from generic application scenarios) is a more realistic representation of potential toxicological effects and a superior method of ranking products for the risk they pose to the aquatic environment.

The toxicity of 13 sewage sludges was evaluated in relation to the crustacean Heterocypris incongruens. The bioassay used was a commercial, direct contact test that allows evaluation of solid-phase toxicity. Evaluation of sewage sludges included physicochemical properties (pH, total organic C, total N, cation-exchange capacity, total exchangeable bases, available forms of P and K, and electrical conductivity), heavy metal content (cadmium, chromium, copper, lead, nickel, and zinc), and content of polycyclic aromatic hydrocarbons (16 from the U.S. Environmental Protection Agency list). The evaluated parameters were then compared with bioassay results (mortality and growth inhibition). Sewage sludges were characterized by optimal physicochemical properties; low K (<5.64 mg/kg) and total organic C (177-253 g/kg) levels were noted. Contaminant content (heavy metals and polycyclic aromatic hydrocarbons) clearly differed between individual sewage sludges. Polycyclic aromatic hydrocarbon contents ranged from 3.8 to 36.4 mg/kg. Total concentrations of heavy metals in all sewage sludges (with the exception of one sludge) were lower than the pollutant concentration limits for land application. Heterocypris incongruens mortality when sludge was applied at doses of 6, 12, or 24% ranged from 0 to 70%, from 4.7 to 72.1%, and from 0 to 100%, respectively. Average growth inhibition was 39.7 to 46.6% (depending on the sludge dose applied). Any stimulating influence of two sewage sludges on the test organism was recorded. The median lethal concentrations calculated for individual sewage sludges ranged from 88 to 956 g sewage sludge/ kg.

We evaluated the occurrence of three antibiotics (roxithromycin, trimethoprim, and chloramphenicol) in surface water and effluents from several sewage treatment plants (STPs) on the Han River, Korea. In addition, standard acute toxicity tests were conducted using the microbe Vibrio fischeri, freshwater macroinvertebrates Daphnia magna and Moina macrocopa, and fish (Oryzias latipes) for these antibiotics. Antibiotics were more frequently detected at higher amounts in effluent samples and in samples collected during the low-flow season. For trimethoprim and chloramphenicol, the levels observed in surface water during low flow were, on average, 108 and 31 ng/L, respectively. These levels were comparable to those measured in the municipal effluents (average, 80 and 37 ng/L, respectively), suggesting the presence of other sources upstream (e.g., livestock wastes). For roxithromycin, surface water levels were approximately an order of magnitude lower than effluent levels. Adverse effects of roxithromycin, trimethoprim, and chloramphenicol were observed at mg/L levels in standard acute aquatic ecotoxicity tests. Based on hazard quotients calculated for the three antibiotics, minimal risks to aquatic systems are suggested. To further increase scientific understanding about the potential impacts of these pharmaceuticals in the environment, however, chronic ecotoxicology studies, with more subtle but ecologically meaningful end points or in combination with other mechanistically related contaminants, may be beneficial.

Contamination of marine environments by hexachlorobenzene (HCB) represents a serious concern for potential consequences on ecosystem and human health. Despite this, information on cytotoxic effects on marine organisms is still largely lacking. In this study, we investigated cytotoxic effects induced by HCB on gonads and muscular tissue of Squilla mantis by analysing Na(+)/K(+)-ATPase activity and plasma membrane fluidity. This crustacean species was selected as a model for its habitat, trophic level, feeding behavior, and commercial exploitation for human consumption. Time course experiments revealed that low concentrations of HCB (i.e. 50 nM) determine an exponentially decrease of Na(+)/K(+)-ATPase activity and a significant modification of cellular membrane fluidity. Significant negative relationships between Na(+)/K(+)-ATPase activity and membrane fluidity were observed, suggesting that changes in the structure and packing of cellular membranes induced by HCB may be the primary factor affecting the activity of essential bilayer-associated enzymes. Overall these findings suggest that even small concentrations of HCB may determine important changes on cell metabolism with potential cascade effects on recruitment of this commercial species.

To investigate how particulate materials and the toxicity of a polluted river can affect biomass production of a particle feeding organism, monthly water samples of the River Lambro were collected upstream and downstream from major pollution sources. These samples were characterized for physical and chemical endpoints, and tested for acute and chronic toxicity (7-day) using Ceriodaphnia dubia. Comparing the effects of unfiltered and filtered water samples, we showed that: (a) despite the higher contamination of the downstream reach, unfiltered (whole) downstream samples often supported a higher biomass production of C. dubia than upstream samples; (b) filtering downstream water samples and thereby removing suspended particulate matter (SPM) controlled this compensatory effect and resulted in a clear inhibition of daphnid biomass production; (c) despite the compensatory and likely nutritional role of particulate materials, an inverse relationship was found between daphnid biomass production and the content of organic carbon of SPM, as well as between the SPM organic content and the temperature of the river. These results show that SPM of the downstream reach can simultaneously exert trophic and toxic effects, and their interaction determines the final result but under the control of major system factors such as water temperature.

The objective of the present study was to study the release and effect of TNT from dumped ammunition. Cleaved artillery shells were placed in static brackish water systems for 5 months, and another 12 months with 5 cm sediment burial. The toxicity was determined in bioassays with crustaceans (Nitocra spinipes and Hyalella azteca) and/or European flounder (Platichtys flesus). The water phase was analysed for TNT using colorimetric method and GC-MS. This study showed a rapid release of TNT to acutely toxic concentrations when the cleaved ammuniton was not covered with sediment under static conditions, but that the release was effectively inhibited by sediment burial of the artillery shells. Hence, at least in a short-term perspective, acute adverse effects of sediment-buried ammunition on aquatic organisms should be greatly reduced.

Limitations relating to permissible standards of undesirable substances in sewage sludges make it necessary to optimize sludge properties. One of the methods to achieve the above goal is the use of a composting process. The aim of this study was to determine the toxicity of composts obtained from sewage sludges composted for 76 days. Dewatered sewage sludges were collected from the four wastewater treatment plants located in the south-eastern part of Poland (Kraśnik, Lublin, Biłgoraj and Zamość). The sludges were mixed with standard OECD soil at doses of 6% and 24%. Phytotoxkit (with Lepidium sativum) and ostracodtoxkit (with Heterocypris incongruens) tests were used to evaluate toxicity. The results obtained showed different toxicity of sewage sludge depending on the sludge dose and bioassay used. H. incongruens mortality ranged from 0% to 90% and depended on the sewage sludge. The greatest inhibition of test organism growth was noted at a level of 55%. In the case of the Phytotoxkit test, a clearly negative influence of the sewage sludges on seed germination was observed at a dose of 24%. Root growth inhibition was noted in the case of most sewage sludges and was at a level of 20-100%. The influence of the composting on the toxicity of biosolids also showed various trends depending on the sludge type. Sludge composting often resulted in a toxicity increase in relation to H. incongruens. In the case of plants (Phytotoxkit test) and most sewage sludges, however, the composting process influenced both the seed germination and root growth in a positive way.

The photochemical behaviour of chlorpromazine (CPZ) and thioridazine (THR) incubated under VIS light and a UV-A lamp was investigated with a high-performance liquid chromatography photodiode array detector (HPLC-PAD) and two bioassays. VIS light caused the decrease of CPZ and THR to 25% and 34% of the initial level, respectively, while UV-A degraded the drugs almost totally. CPZ and THR were very toxic to the protozoan Spirostomum ambiguum (Spirotox) and anostracan crustacean Thamnocephalus platyurus (Thamnotoxkit F) with 24-h LC50 values of around 0.5 mg l(-1). In spite of the drastic decrease of the concentration of the drugs, the irradiated samples were toxic to the protozoan, especially when a sublethal end-point was taken into consideration. Contrary to the protozoan the crustacean was not sensitive to the products of photodegradation. Mass spectrometry analysis showed the presence of dimers and trimers of the CPZ and mono-, di-, and tri-oxygenated derivatives of THR. The presented data give a strong indication of the importance of the investigation of the environmental fate of drugs, especially those known to be phototoxic.

Sewage sludges and the composts were evaluated chemically and ecotoxicologically to determine their suitability as fertilizers for land application. Four municipal sewage sludges with various properties and pollutant contents were composted in aerobic conditions for 76 days. The content of heavy metals (Cd, Cu, Cr, Pb, Ni, Zn) and polycyclic aromatic hydrocarbons (14 from US EPA List) was analyzed in the sewage sludges and composts as well as together with their physico-chemical properties (total organic carbon, total nitrogen, pH, available forms of magnesium, phosphorus and potassium, cations content, cation exchange capacity, total of exchangeable bases). To evaluate the toxicity of the materials, bioassays with crustacean Heterocypris incongruens (Ostracodtoxkit test) were performed. Neither physical-chemical properties nor heavy metal content underwent any significant changes during the composting process. However, composting significantly influenced the range of losses of polycyclic aromatic hydrocarbons. The magnitude and the ranges of changes in the toxicity H. incongruens were found to be dependent on the tested parameter as well as on sewage sludge type and its dose. It was noted that composting could even increase the toxicity of sewage sludges. Sewage sludge toxicity was mainly determined by the presence of heavy metals, although for some sludges the contribution of organic pollutants as well as the synergistic activity of several factors could not be excluded. According to proposed classification (on the basis of Ostracodtoxkit test) only one sewage sludge/compost was suitable for land application. The studies conducted provide interesting information pointing to the necessity to supplement chemical studies with biological assays.

Meiofauna composition was investigated for six field sites, including polluted and non-polluted sites, within two regions (Auckland and Bay of Plenty) during winter (July-August 2004) in the North Island of New Zealand. Physico-chemical parameters were measured during the sampling period and meiofauna distribution and abundance were compared with these measured parameters. Analysis of meiofauna abundance indicated that foraminiferans, nematodes and ostracods were the taxa that contributed to the variability between field sites within the Auckland region. However, no clear taxa dominance was seen in the Bay of Plenty region. Comparison of meiofauna abundance and physico-chemical parameters was done using multivariate analysis (PRIMER). However, no clear relationships between the parameters were observed in any field site in either region. The Shannon-Weiner index of diversity did not show any clear differentiation between polluted and non-polluted field sites. Therefore, from the present study, the taxa or physico-chemical parameters used could not effectively characterise pollution at the investigated field sites.

In the larval stages of three euryhaline species of the genus Armases, we tested if changes in biomass (dry mass, W; protein; lipid) under hyposmotic stress were related to their salinity tolerance, capabilities of osmoregulation, and migration patterns. As model species, we compared Armases miersii, which breeds in supratidal rock pools, the riverine crab Armases roberti (showing a larval export strategy), and Armases ricordi, whose larvae probably develop in coastal marine waters. At each stage, larvae were exposed to different salinities (selected according to previous information on larval survival; range: 5 per thousand-32 per thousand for A. miersii, 10 per thousand-32 per thousand for A. roberti, and 15 per thousand-32 per thousand for A. ricordi). Biomass was measured in early postmoult and intermoult. The larvae of the strongly osmoregulating species A. miersii, which develop in habitats with highly variable salinity conditions, showed the smallest variations in biomass. The effect on A. roberti varied during its ontogeny: the Zoea I and the Megalopa, which carry out downstream and upstream migrations, respectively, showed lower biomass variations than the intermediate zoeal instars, which develop in coastal waters. The larvae of A. ricordi showed generally the highest variations in biomass, reflecting poor adaptation to salinity variations. In addition, a common pattern was found for these estuarine species: the maximum of biomass shifted during ontogeny from 32 per thousand to 25 per thousand, reflecting changes of the iso-osmotic point. The ontogeny of osmoregulation reflected ontogenetic migration patterns, which allow for avoiding detrimental effects of salinity variations.

The aim of this study was to characterize cholinesterase (ChE) activity in Gammarus pulex, an abundant and ecologically relevant species of the European stream environment. Biochemical and pharmacological properties were tested using different substrates (acetylthiocholine iodide, propionylthiocholine iodide and butyrylthiocholine iodide) and selective inhibitors (eserine sulfate, BW284c51 and iso-OMPA). In a second part, the in vitro and in vivo effects of a widely used organophosphorous pesticide, chlorpyrifos, on ChE activity were investigated. The results suggest that G. pulex possess only one ChE which displays the typical properties of an acetylcholinesterase, since: (1) it hydrolyses to the substrate acetylthiocholine at a higher rate than all other tested substrates and (2) it is highly sensitive to eserine sulphate and BW284c51, but not to iso-OMPA. In vitro and in vivo inhibitions were observed for highly different contamination levels, which suggests that bioaccumulation and biotransformation mechanisms are involved. In vivo AChE inhibition was observed at realistic environmental concentrations, with lethal effects appearing at inhibitions higher than 50%. The results of this study show the value of G. pulex as a sentinel organism for environmental assessment.

Lipid regulators have been detected in effluents from sewage treatment plants and surface waters from humans via excretion. This study was designed to assess the ecotoxicity of fibrates, lipid regulating agents. The following compounds were investigated: Bezafibrate, Fenofibrate and Gemfibrozil and their derivatives obtained by solar simulator irradiation. Bioassays were performed on bacteria, algae, rotifers and microcrustaceans to assess acute and chronic toxicity, while SOS Chromotest and Ames test were utilized to detect the genotoxic potential of the investigated compounds. The photoproducts were identified by their physical features and for the first risk evaluation, the environmental impact of parental compounds was calculated by Measured Environmental Concentrations (MEC) using the available data from the literature regarding drug occurrence in the aquatic environment and the Predicted No Effect Concentrations (PNEC) based on our toxicity data. The results showed that acute toxicity was in the order of dozens of mg/L for all the trophic levels utilized in bioassays (bacteria, rotifers, crustaceans). Chronic exposure to these compounds caused inhibition of growth population on rotifers and crustaceans while the algae seemed to be slightly affected by this class of pharmaceuticals. Genotoxic and mutagenic effects were especially found for the Gemfibrozil photoproduct suggesting that also byproducts have to be considered in the environmental risk of drugs.

The results from the multimillion dollar Enrichment of Nutrients on Coral Reefs Experiment (ENCORE) on One Tree Island Reef (OTIR) suggest that increased nutrient loads to coral reefs will have little or no effect on the algal growth rates and, hence, on the associated effects that increased algal growth might have on the functioning and stability of coral reefs. However, a comparison of the concentrations of nutrients within the OTIR lagoon with the proposed nutrient threshold concentrations (NTC) for coral reefs suggests that all sites, including the control sites, were saturated with nutrients during ENCORE, and, hence, one would not expect to get any differences between treatments in the algal-growth related measurements. Thus, ENCORE results provide strong support for the proposed NTCs and support the ecological principle that algal productivity and, consequently, the functioning of coral reefs are sensitive to small changes in the background concentrations of nutrients. The principal conclusion of ENCORE, namely that the addition of nutrients did not cause the "pristine" OTIR to convert from coral communities to algal dominated reefs, is contrary to the fact that there was prolific macroalgal growth on the walls and crests of the experimental microatolls by the end of ENCORE.

The toxicity of polycyclic aromatic hydrocarbons (PAHs) to Hyalella azteca, was measured in 34 sediment samples collected from four manufactured-gas plant (MGP) sites ranging in total PAH16 (sum of 16 U.S. Environmental Protection Agency priority pollutant PAHs) concentrations from 4 to 5700 mg/kg, total organic carbon content from 0.6 to 11%, and soot carbon from 0.2 to 5.1%. The survival and growth of H. azteca in 28-d bioassays were unrelated to total PAH concentration, with 100% survival in one sediment having 1,730 mg/kg total PAH16, whereas no survival was observed in sediment samples with concentrations as low as 54 mg/kg total PAH16. Twenty-five of the 34 sediment samples exceeded the probable effects concentration screening value of 22.8 mg/kg total PAH13 (sum of 13 PAHs) and equilibrium partitioning sediment benchmarks for PAH mixtures (on the basis of the measurement of 18 parent PAHs and 16 groups of alkylated PAHs, [PAH34]); yet, 19 (76%) of the 25 samples predicted to be toxic were not toxic to H. azteca. However, the toxicity of PAHs to H. azteca was accurately predicted when either the rapidly released concentrations as determined by mild supercritical fluid extraction (SFE) or the pore-water concentrations were used to establish the bioavailability of PAHs. These results demonstrate that the PAHs present in many sediments collected from MGP sites have low bioavailability and that both the measurement of the rapidly released PAH concentrations with mild SFE and the dissolved pore-water concentrations of PAHs are useful tools for estimating chronic toxicity to H. azteca.

As part of the Endis-Risks project, the current study describes the occurrence of the chlorotriazine pesticides atrazine, simazine and terbutylazine in water, sediment and suspended matter in the Scheldt estuary (B-Nl) from 2002 to 2005 (3 samplings a year, 8 sampling points). Atrazine was found at the highest concentrations, varying from 10 to 736 ng/l in water and from 5 up to 10 ng/g in suspended matter. Simazine and terbutylazine were detected at lower concentrations. Traces of the targeted pesticides were also detected in sediments, but these were below the limit of quantification. As part of an ecotoxicological assessment, we studied the potential effect of atrazine on molting of Neomysis integer (Crustacea:Mysidacea), a resident invertebrate of the Scheldt Estuary and a proposed test organism for the evaluation of endocrine disruption. Following chronic exposure ( approximately 3 weeks), atrazine did not significantly affect mysid molting at environmentally relevant concentrations (up to 1 microg/l).

Transformation of tamoxifen has been observed in water by prolonged sunlight irradiation. The main photoproducts, isolated by chromatographic techniques, have been identified by spectroscopic means. Photoisomerization, photocyclization and, to a lesser extent, photooxygenation appear to be involved in the degradation of the drug. The acute and chronic toxicity of the parent drug and its photoproducts were tested on non-target aquatic organisms (Brachionus calyciflorus, Thamnocephalus platyurus, Daphnia magna and Ceriodaphnia dubia). Exposure to all the compounds induced mainly chronic effects without significant differences among the parental and derivative compounds.