Synergistic effect of two-and four-component combinations of the polycyclic aromatic hydrocarbons: Phenanthrene, anthracene, naphthalene and acenaphthene on Daphnia magna (original) (raw)
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Aquatic Toxicology, 2011
Organisms in marine sediments are usually exposed to mixtures of polycyclic aromatic hydrocarbons (PAHs), whereas risk assessment and management typically focus on the effects of single PAHs. This can lead to an underestimation of risk if the effects of single compounds are additive or synergistic. Because of the virtually infinite number of mixture-combinations, and the many different targeted organisms, it would be advantageous to have a model for the assessment of mixture effects. In this study we tested whether chemical activity, which drives the partitioning of PAHs into organisms, can be used to model the baseline toxicity of mixtures. Experiments were performed with two benthic amphipod species (Orchomonella pinguis and Corophium volutator), using passive dosing to control the external exposure of single PAHs and mixtures of three and four PAHs. The baseline toxicity of individual PAHs at water saturation generally increased with increasing chemical activity of the PAHs. For O. pinguis, the baseline toxicity of PAH mixtures was successfully described by the sum of chemical activities. Some compounds and mixtures showed a delayed expression of toxicity, highlighting the need to adjust the length of the experiment depending on the organism. On the other hand, some of the single compounds had a higher toxicity than expected, possibly due to the toxicity of PAH metabolites. We suggest that chemical activity of mixtures can, and should, be used in addition to toxicity data for single compounds in environmental risk assessment.
Chemosphere, 2003
Polycyclic aromatic hydrocarbons (PAHs) are considered to act additively when exposed as congener mixtures. Additive internal concentrations at the site of toxic action is the basis for recent efforts to establish a sum PAH guideline for sediment-associated PAH toxicity. This study determined the toxicity of several PAH congeners on a body residue basis in Diporeia spp. These values were compared to the previously established LR 50 value for a PAH mixture based on the molar sum of PAH congeners and demonstrated similar LR 50 values for individual PAH. These results support the contention that the PAH act at the same molar concentration whether present as individual compounds or in mixture. Aqueous exposures were conducted for 28 d, and the water was exchanged daily to maintain the exposure concentration. The concentration in the exposures declined by an average of 22% between water exchanges across all compounds, and ranged from 11% to 32%. The toxicokinetics were determined using both time-weighted-average (TWA) and time-variable water concentrations and were not statistically different between the two source functions. Toxicity was determined for both mortality and immobility (failure to swim on prodding) and on both a TWA water concentration and a body residue basis. The LC 50 values ranged from 1757 lg l À1 for naphthalene after 10 d exposure to 79.1 lg l À1 for pyrene after 28 d exposure, and the EC 50 ranged from 1587 lg l À1 for naphthalene after 10 d exposure to 38.2 lg l À1 for pyrene after 28 d exposure. The LR 50 values for all congeners at all lengths of exposure were essentially constant and averaged 7:5 AE 2:6 lmol g À1 , while the ER 50 for immobility averaged 2:6 AE 0:6 lmol g À1 . The bioconcentration factor declined with increasing exposure concentration and was driven primarily by a lower uptake rate with increasing dose, while the elimination remained essentially constant for each compound. Published by Elsevier Science Ltd.
Ecotoxicology and Environmental Safety, 2009
In our previous studies we assessed the biochemical response of juvenile seabream to the exposure to three selected polycyclic aromatic hydrocarbons (PAHs) (phenanthrene, pyrene and fluorene) in shortterm laboratory experiments. Since in the analyses conducted in the field it is much more natural to expect the presence of multiple contaminants at the same time, the objective of this study was to analyse the reaction of seabream to the exposure to a mix of the three PAHs tested previously. The proportions of the individual components in the PAH mix used in our experiments were constant and determined on the basis of the concentration addition concept.
The Scientific World Journal, 2012
PAHs were measured in water, sediment, and shrimps of Estero de Urias, an estuary in Sinaloa, Mexico, during the rainy and dry seasons, and analyzed for eleven PAHs routinely detected in samples. Phenanthrene was the most dominant congener in the water, sediment, and shrimp samples comprising about 38, 24, and 25%, respectively, of the eleven PAHs detected, followed by pyrene and naphthalene in water and sediment samples, and pyrene and fluorine in the shrimp samples. Total PAH concentrations ranged from 9 to 347 ng/L in water, 27 to 418 ng/g in sediments, and 36 to 498 ng/g in shrimps. The sources of contamination are closely related to human activities such as domestic and industrial discharge, automobile exhausts, and street runoff. High concentrations were also measured during the rainy season and during the first quarter of the year. Toxicity tests were also carried out, exposing fish embryos and juvenile shrimps to some of these PAHs. Fish embryos exposed to PAHs showed exogas...
Chemosphere, 2012
The acute toxicity (96 h) of pyrene (PY) to European seabass (Dicentrachus labrax) juveniles assessed in a semi-static bioassay (SSB) with medium renewal at each 12 h, and in a static bioassay (SB) without medium renewal was compared in laboratorial conditions (water PY concentrations: 0.07-10 mg L À1 ). Main findings in the SSB that assessed mainly the toxicity of PY and its metabolites were: increased levels of bile PY metabolites in good agreement with the profile of lipid peroxidation levels (LPO) in exposed fish relating PY exposure and oxidative damage; increased levels of PY-type compounds in the brain indicating their ability to cross the blood-brain barrier; increased levels of these substances in liver and muscle which are edible tissues for humans thus raising concern on potential adverse effects on consumers of fish from PY contaminated areas; a significant inhibition of glutathione S-transferase activity suggesting its involvement in PY detoxication as toxicant scavenger; finally, an almost complete impairment of the swimming velocity at all the PY concentrations linking sub-individual to higher population level effects. In the SB, where the overall toxicity of PY, its metabolites and environmental degradation products was evaluated, 19% and 79% of PY decay in test media was found at 12 and 96 h, respectively. In general, the effects were similar to those of SSB but with significant effects being induced at higher PY concentrations indicating that the parental compound is more toxic than its environmental degradation products. The other main differences relatively to the SSB were: increased levels of PY-type substances in the liver suggesting more accumulation in this organ. Therefore, these findings highlight the need of carefully considering experimental design options when assessing the toxicity of readily degradable substances to marine fish, and stress the importance of taking into consideration the toxicity of environmental degradation products in addition to toxic effects of the parental substance and its metabolites for marine ecological risk assessment.
Environmental Pollution, 2020
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Procedia Engineering, 2016
Polycyclic aromatic hydrocarbons (PAHs) are pollutants released to the environment through natural and anthropogenic activities. PAHs if not being treated properly, are able to be transformed to various derivatives (daughters). There are possibilities that both PAHs and their daughter products to be toxic to environment and human. In this study, samples from influent of a water treatment plant (WTP) and effluent of sewage treatment plant (STP) were obtained to investigate presence of PAHs and their derivatives. Analysis of samples were conducted using Gas Chromatography Mass Spectrometry (GC/MS) and conversion formulation of the identified PAHs were found out. Furthermore, toxicity study carried out using guppy (Poecilia reticulate) to establish toxicity intensity of PAHs parents and daughters. The experiments were performed with three replicates using a total of 100 guppies for all definite tests through steady state method of acute toxicity test and mortality rates were investigated in 24, 48, 72 and 96 hours. Results indicated that phthalic acid and benzoic acid are significant compounds in both sampling points. Phthalic acid was found to be derived from Chrysene and Naphthalene whereas benzoic acid resulted from degradation of Fluoranthene. Mortality rates were 20% and 10%, in WTP influent and STP effluent, respectively. No mortality was observed in control tank which indicated accuracy of toxicity test. Although, the pollution levels in both samples did not produce 50% mortality, the findings could indicate the conditions affecting fish populations in prolonged duration.