Algal growth inhibition test results of 425 organic chemical substances.

The toxicity towards the algal species Pseudokirchneriella subcapitata of 425 organic chemical substances was tested in a growth inhibition test. Precautions were taken to prevent loss of the compounds from the water phase and the test system (closed test system, low biomass, shorter test duration, silanized glass) and to keep pH constant by applying a higher alkalinity. Chemical phase distribution was modelled taking ionization, volatilisation, and adsorption to glass and biomass into consideration.

Testing lagoonal sediments with early life stages of the copepod Acartia tonsa (Dana): An approach to assess sediment toxicity in the Venice Lagoon.

The early-life stages of development of the calanoid copepod Acartia tonsa from egg to copepodite I is proposed as an endpoint for assessing sediment toxicity by exposing newly released eggs directly onto the sediment-water interface. A preliminary study of 5 sediment samples collected in the lagoon of Venice highlighted that the larval development rate (LDR) and the early-life stages (ELS) mortality endpoints with A. tonsa are more sensitive than the standard amphipod mortality test; moreover LDR resulted in a more reliable endpoint than ELS mortality, due to the interference of the sediment with the recovery of unhatched eggs and dead larvae.

Effect of Fenton treatment on the aquatic toxicity of bisphenol A in different water matrices.

Battery tests serve as integral tools to decide whether a treatment process is ecotoxicologically safe or not. In the present study, a battery of toxicity tests was employed to elucidate the toxicity of the potential endocrine-disrupting pollutant bisphenol A (BPA) and its advanced oxidation products. For this purpose, BPA was subjected to Fenton treatment in the growth medium of the test organisms employed as well as in real lake water.

Identification and ecotoxicity of degradation products of chloroacetamide herbicides from UV-treatment of water.

The widespread occurrence of chlorinated herbicides and their degradation products in the aquatic environment raises health and environmental concerns. As a consequence pesticides, and to a lesser degree their degradation products, are monitored by authorities both in surface waters and drinking waters. In this study the formation of degradation products from ultraviolet (UV) treatment of the three chloroacetamide herbicides acetochlor, alachlor and metolachlor and their biological effects were investigated.

Effect of pH on the toxicity and bioconcentration of sulfadiazine on Daphnia magna.

The antimicrobial sulfonamide sulfadiazine has in the last decades been detected in environmental water bodies, both surface and ground water. Since pH in the environment may vary considerably, this study examined the toxicity of the amphoter sulfadiazine towards Daphnia magna at pH levels of 6.0, 7.

Ecotoxicity of carbamazepine and its UV photolysis transformation products.

Carbamazepine, an anti-epileptic pharmaceutical agent commonly found in wastewater, is highly recalcitrant to standard wastewater treatment practices. This study investigated the mixture toxicity of carbamazepine transformation products formed during ultraviolet (UV) photolysis using three standard ecotoxicity assays (representing bacteria, algae and crustaceans). UV-treatment of 6 mg L(-1) carbamazepine solution was carried out over a 120 min period and samples were removed periodically over the course of the experiment.

The challenges of testing metal and metal oxide nanoparticles in algal bioassays: titanium dioxide and gold nanoparticles as case studies.

Aquatic toxicology of engineered nanoparticles is challenged by methodological difficulties stemming partly from highly dynamic and poorly understood behavior of nanoparticles in biological test systems. In this paper scientific and technical challenges of testing not readily soluble nanoparticles in standardised algal growth inhibition tests are highlighted with specific focus on biomass quantification methods. This is illustrated through tests with TiO2 and Au nanoparticles, for which cell-nanoparticle interactions and behavior was studied during incubation.

Critical evaluation and further development of methods for testing ecotoxicity at multiple pH using Daphnia magna and Pseudokirchneriella subcapitata.

To meet the requirements of risk assessment legislature regarding the ecotoxicity of ionizing compounds, the present study attempts to establish easy, robust methods for testing ecotoxicity at various pH levels. An overview is given of the buffering methods found in the literature. This is supplemented by a series of experiments where toxicity and ability to stabilize pH of seven common buffering compounds was tested on Daphnia magna and Pseudokirchneriella subcapitata.

Optimal choice of pH for toxicity and bioaccumulation studies of ionizing organic chemicals.

It is recognized that the pH of exposure solutions can influence the toxicity and bioaccumulation of ionizing compounds. The present study investigates whether it can be considered a general rule that an ionizable compound is more toxic and more bioaccumulative when in the neutral state. Three processes were identified to explain the behavior of ionizing compounds with changing pH: the change in lipophilicity when a neutral compound becomes ionized, electrical attraction, and the ion trap.

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

Benzophenone (BP)-type ultraviolet (UV) filters are widely used in cosmetic and sunscreen products and can enter the aquatic environment. Therefore, we investigated the subchronic toxicity of 2,4-dihydroxybenzophenone (BP1) on the marine calanoid copepod Acartia tonsa in an early life-stage development study. Since developmental endpoints depend on environmental conditions, a preceding study of A.

The effect of pH on the uptake and toxicity of the bivalent weak base chloroquine tested on Salix viminalis and Daphnia magna.

The uptake and accumulation of most electrolytes will change with pH because of the different speciation states of these compounds at various pH. Non-ionized compounds will partition into fatty and organic phases (such as cell membranes) more readily than the corresponding charged compounds, and therefore a higher toxicity can be expected. The current study examines the pH-dependent toxicity and bioaccumulation of the bivalent weak base chloroquine (pK(a): 10.

Endocrine potency of wastewater: contents of endocrine disrupting chemicals and effects measured by in vivo and in vitro assays.

Industrial and municipal effluents are important sources of endocrine disrupting compounds (EDCs) discharged into the aquatic environment. This study investigated the endocrine potency of wastewater and the cleaning efficiency of two typical urban Danish sewage treatment plants (STPs), using chemical analysis and a battery of bioassays. Influent samples, collected at the first STP grate, and effluent samples, collected after the sewage treatment, were extracted using solid phase extraction.

Uptake, accumulation, phytotoxicity, and removal of 2,4-dichlorophenol in willow trees.

The relation between uptake, accumulation, toxicity and removal of 2,4-dichlorophenol (2,4-DCP) in willow trees (Salix viminalis) and the feasibility of implementing phytoremediation as a treatment method for 2,4-DCP contamination in wastewater and soil were investigated. Willows were exposed to various 2,4-DCP concentrations between 5 and 150 mg/L in hydroponic solution and between 9.1 and 44.

COMPRENDO: Focus and approach.

Tens of thousands of man-made chemicals are in regular use and discharged into the environment. Many of them are known to interfere with the hormonal systems in humans and wildlife. Given the complexity of endocrine systems, there are many ways in which endocrine-disrupting chemicals (EDCs) can affect the body's signaling system, and this makes unraveling the mechanisms of action of these chemicals difficult.

Inhibition of larval development of the marine copepod Acartia tonsa by four synthetic musk substances.

A nitro musk (musk ketone) and three polycyclic musks (Tonalide, Galaxolide and Celestolide) were tested for acute and subchronic effects on a marine crustacean, the calanoid copepod Acartia tonsa. Sublethal effects on A. tonsa larvae were investigated with a rapid and cost effective bioassay, which is based on the easily detectable morphological change from the last nauplius to the first copepodite stage during copepod larval development.