Toxicity Of Phenanthrene Research Articles

Influence of phenanthrene and fluoranthene on the degradation of fluorene and glucose by Sphingomonas sp. strain LB126 in chemostat cultures

Since bacteria degrading polycyclic aromatic hydrocarbon compounds (PAHs) in polluted soils are generally exposed to mixtures of PAHs, we examined the influence of simple PAH mixtures on the degradation activity of Sphingomonas sp. strain LB126. Fluorene serves as sole carbon and energy source for the strain LB126 and phenanthrene and fluoranthene are cometabolically degraded by this species. Chemostat cultures of the strain LB126 were used to study a potential inhibiting effect of phenanthrene and fluoranthene on the degradation of fluorene that was previously observed in batch cultures. We also looked at the effect of phenanthrene on the degradation of glucose in a chemostat culture to see if this effect was specific for the PAH-metabolic pathway or for the total metabolism of the strain. The co-substrates were supplied in a 5% to 30% fraction of fluorene. Phenanthrene and fluoranthene had no significant influence on growth. However, fluorene degradation was inhibited by both phenanthrene and fluoranthene. The effect of phenanthrene was about 10 times stronger than the effect of fluoranthene. Nevertheless, more than 95% removal of fluorene took place together with more than 95% removal of either phenanthrene or fluoranthene. The effect of phenanthrene on the strain LB126 could be ascribed to both toxicity and competitive inhibition, but the effect observed at steady state was due to competitive inhibition only. It appeared that the strain LB126 adapts to the toxicity of phenanthrene within five generations. The inhibitory effects observed previously in batch cultures of the strain LB126 should mainly be ascribed to the toxic effect of phenanthrene.

Nitrite-induced enhancement of toxicity of phenanthrene in fish and its implications for coastal waters

Coastal areas are prone to varying degrees of anthropogenic chemical contamination. In many coastal environments experiencing reducing conditions in the water column, nitrite is produced as a result of denitrification. With a view to determining the effect of a natural stress such as the presence of nitrite in water on the xenobiotic metabolism in fish, the euryhaline cichlid Oreochromis mossambicus was exposed for up to 9 days to environmentally relevant concentrations of water-borne nitrite and phenanthrene, a polycyclic aromatic hydrocarbon. Analyses of different biomarkers in the treated fish indicated significant increase in the metabolism of phenanthrene as a result of exposure to nitrite. For example, the activity of the biotransformation enzyme measured as 7-ethoxyresorufin- O-deethylase activity was, in the presence of 1 μM nitrite, nearly twice that produced by phenanthrene alone. Similarly, biliary fixed fluorescence values reflecting phenanthrene and its metabolites were rendered 1.7 times higher when exposed simultaneously to nitrite. Contact with nitrite and phenanthrene together also led to severe hepatic damage with possible cell death as inferred from the large enhancement in sorbitol dehydrogenase activity in the serum and reduced liver somatic index.

Altering cytochrome P4501A activity affects polycyclic aromatic hydrocarbon metabolism and toxicity in rainbow trout (Oncorhynchus mykiss)

The polycyclic aromatic hydrocarbons (PAHs) phenanthrene and retene (7-isopropyl-1-methyl phenanthrene) are lethal to rainbow trout (Oncorhynchus mykiss) larvae during chronic exposures. Phenanthrene is a low-toxicity, non-cytochrome P4501A (CYP1A)-inducing compound that accumulates in fish tissues during exposure to lethal concentrations in water. Retene is a higher toxicity CYP1A-inducing compound that is not detectable in tissue at lethal exposure concentrations. The metabolism, excretion, and toxicity of retene and phenanthrene were examined in juvenile and larval rainbow trout during coexposure to the model CYP1A inducer beta-naphthoflavone (betaNF), or to the inducer-inhibitor piperonyl butoxide to determine if modulating CYP1A activity affected PAH metabolism and toxicity. Phenanthrene metabolism, excretion rate, and toxicity increased with coexposure to betaNE Piperonyl butoxide inhibited phenanthrene metabolism and reduced the excretion of all phenanthrene metabolites. As a consequence, embryo mortality rates increased but rates of sublethal effects did not. Coexposure of trout to retene and betaNF caused no change in retene metabolism and excretion, but retene toxicity increased, perhaps due to additivity. Piperonyl butoxide inhibited retene metabolism, decreased the excretion of some retene metabolites while increasing the excretion of others, and increased the toxicity of retene. These results support the role of CYP1A activity in PAH metabolism and excretion, and the role ofthe CYP1A-generatedmetabolites of PAHs in chronic toxicity to larval fish.

Studies on the effect of soil aging on the toxicity of pyrene and phenanthrene to a soil-dwelling springtail

Soil samples spiked with five concentrations of pyrene and phenanthrene were aged for 0, 10, 40, and 120 d before toxicity was investigated using a standardized bioassay with the soil-dwelling collembolan Folsomia fimetaria L. Toxic effects were measured as reductions in survival and reproductive output after 3 weeks of exposure. Both pyrene and phenanthrene were degraded in the test system during storage, phenanthrene to a higher degree than pyrene. However, when toxic effects of the tested substances were calculated on the basis of measured concentrations of the parent compounds, toxicity was unaffected by storage for up to 120 d. Many studies have shown a negative correlation between aging and the biodegradation of polycyclic aromatic hydrocarbons (PAHs), indicating a reduction in the bioavailability of PAHs to micro-organisms with time. Our results indicate that a reduction in toxicity, as related to the measured concentrations of the parent compounds in the soil, may not always be expected for aged soils. Provided that metabolites of pyrene and phenanthrene did not significantly contribute to the toxicity in aged soil samples, a possible explanation for the absence of aging effects is the high test concentrations used in combination with the low content of organic carbon (1.6%) in the test soil.

Soil biosensor for the detection of PAH toxicity using an immobilized recombinant bacterium and a biosurfactant

A biosensor for detecting the toxicity of polycylic aromatic hydrocarbons (PAHs) contaminated soil has been successfully constructed using an immobilized recombinant bioluminescent bacterium, GC2 ( lac:: luxCDABE), which constitutively produces bioluminescence. The biosurfactant, rhamnolipids, was used to extract a model PAH, phenanthrene, and was found to enhance the bioavailability of phenanthrene via an increase in its rate of mass transfer from sorbed soil to the aqueous phase. The monitoring of phenanthrene toxicity was achieved through the measurement of the decrease in bioluminescence when a sample extracted with the biosurfactant was injected into the minibioreactor. The concentrations of phenanthrene in the aqueous phase were found to correlate well with the corresponding toxicity data obtained by using this toxicity biosensor. In addition, it was also found that the addition of glass beads to the agar media enhanced the stability of the immobilized cells. This biosensor system using a biosurfactant may be applied as an in-situ biosensor to detect the toxicity of hydrophobic contaminants in soils and for performance evaluation of PAH degradation in soils.

Single and combined effects of sediment-associated PAHs on three species of freshwater macroinvertebrates.

Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous pollutants of sediments. Sediment quality criteria often use toxicity data for individual PAHs. However, PAHs always occur in field sediments as a complex mixture of compounds. In this study, the toxicity of phenanthrene (P), fluoranthene (FLA) and benzo(k)-fluoranthene (B), alone or in combination, was assessed using monospecific sediment tests of acute toxicity (between 24 h and 14 days). The test sediments were spiked formulated sediments. Toxicity of PAHs was determined on a freshwater pelagic organism, Daphnia magna, on an epibenthic organism, Hyalella azteca, and on a benthic organism, Chironomus riparius. The phototoxicity of fluoranthene and phenanthrene was verified. Benzo(k)fluoranthene was not phototoxic and presented no toxicity for the three organisms tested up to 300 mg/kg, concentration rarely found in the environment. For all PAHs, the toxicity towards Daphnia magna was two-fold higher in the sediment toxicity tests than in the water-only standard tests, probably due to suspended contaminated particles and contact of daphnids with sediment. For phenanthrene, the LC50s found were 50, 15 and 20 mg/kg dry weight sediment, respectively for Daphnia magna, Hyalella azteca and Chironomus riparius. The bioassays on fluoranthene yielded LC50s of 10, 5 and 15 mg/kg dw respectively for Daphnia magna, Hyalella azteca and Chironomus riparius. LC50s of the PAHs mixture (1/3 of each compound by weight) were around 10 mg/kg dry weight sediment for Hyalella azteca and 20 mg/kg for Chironomus riparius. The effects of PAHs in the mixture seemed to be synergistic. This study gives new data about PAH toxicity and showed that the additivity of PAH effects could be inadequate to assess the environmental risk.

Changes of toxicological properties of biodegradation products of anthracene and phenanthrene

The aim of this work was to determine toxicity and mutagenicity of anthracene and phenanthrene and their microbial biotransformation products. The following representatives of different trophic levels of aquatic biocenoses were selected for the toxicological tests: Selenastrum capricornutum, Lemna minor, Daphnia magna and Lebistes reticulatus. Mutagenic properties were determined by Ames test. Results of the analyses confirmed toxicity of studied PAHs for test organisms. Metabolites produced during biological degradation of anthracene and phenanthrene were also harmful for selected representatives of aquatic ecosystems.

Effects of surfactant addition on the biomineralization and microbial toxicity of phenanthrene.

Surfactants are known to increase the apparent aqueous solubility of polycyclic aromatic hydrocarbons and may thereby enhance their bioavailability. In this study the effects of four surfactants on the mineralization of phenanthrene by Pseudomonas aeruginosa in liquid culture and in soil-water suspensions was studied in batch reactors over a 15-week study period. In the absence of surfactant, liquid cultures mineralized approximately 50% of the phenanthrene added within seven weeks following a one-week lag period and an initial mineralization rate of 0.04 mg/d. Mineralization in soil-water suspensions proceeded without any measurable lag period. The initial mineralization rate was lower (0.006 mg/d), but mineralization continued to >70% over the fifteen week period. In general, the addition of very low concentrations of surfactant (<0.001%) to liquid cultures did not impact mineralization significantly. At higher surfactant concentrations (>CMC) all surfactants were seen to be inhibitory. In soil-water systems, the rate of phenanthrene mineralization was decreased even at surfactant doses that did not produce significant solubilization. In summary, none of the surfactants enhanced the mineralization of phenanthrene by P. aeruginosa in liquid culture or in soil-water suspensions. In order to rank surfactant toxicity, microbial toxicity tests were performed measuring the light output of bioluminescent bacteria as affected by the presence of surfactants. Additional toxicity testing indicated that the presence of solubilized phenanthrene increased the toxicity of the surfactant by a 100-fold suggesting that the toxicity of solubilized substrate needs also to be considered in the application of surfactant-amended remediation.

Detoxification of fluorene, phenanthrene, carbazole and p-cresol in columns of aquifer sand as studied by the Microtox® assay

The changing in the toxicity of mixtures of creosote-related compounds during their aerobic biodegradation was studied in columns of saturated aquifer material. The Microtox® assay was used to measure the toxicity of phenanthrene, fluorene, carbazole and p-cresol, added individually or in a mixture and to evaluate their detoxification during migration through the columns. When tested alone, phenanthrene, fluorene and p-cresol, inhibited Vibrio fischeri luminescence emission (15 min IC 50=140, 750, 1500 μg/L respectively). In contrast, the toxicity of carbazole was minimal. Phenanthrene, fluorene and carbazole, added concomitantly at concentrations varying between 30 and 300 μg/L, produced between 24.4 and 49.3% inhibition. Comparison with individual toxicity responses suggested antagonistic interaction between these compounds. The toxicity of the mixture solutions decreased upon passage through the columns since the inhibition caused by the effluent solutions averaged 6%. Additionally, p-cresol (10,000 μg/L) enhanced the efficiency of detoxification of the column system; the inhibition by the compound mixture decreased from 81.4% (SD=2.0) to 15.8% (SD=1.8) after having passed through the first 3.8 cm of the column, and was undetectable at the two other downgradient ports. A comparison of the data of product disappearance and changes in toxicity indicated that detoxification was the result of the disappearance of phenanthrene and p-cresol. However, the persistence of fluorene and/or potential metabolites seemed to have caused some residual toxicity.

Photoactivation and toxicity of mixtures of polycyclic aromatic hydrocarbon compounds in marine sediment

AbstractThe direct toxicity and photoinduced toxicity of sediment‐associated acenaphthene, phenanthrene, fuoranthene, and pyrene were determined for the marine amphipod Rhepoxynius abronius. The four polycyclic aromatic hydrocarbons (PAHs) were spiked into sediment in a concentration series of either single compounds or as approximately equitoxic mixtures of all four compounds. Standard 10‐d sediment toxicity tests were conducted under fluorescent lighting. After 10 d, survivors were exposed for 1 h to ultraviolet (UV) radiation in the absence of sediment and then tested for their ability to bury in uncontaminated sediment. The 10‐d median lethal concentrations (LC50s) were 2.31 mg acenaphthene/g organic carbon (OC), 2.22 mg phenanthrene/g OC, 3.31 mg fluoranthene/g OC, and 2.81 mg pyrene/g OC These LC50s were used to calculate the sum of toxic units (ΣTU) of the four PAHs in the approximately equitoxic mixtures. The ΣTU LC50 was then calculated for the mixture treatments. If the toxicologic interaction of a mixture of contaminants is additive, ΣTU LC50 =1.0. The observed LC50 (1.55 ΣTU) was slightly, but significantly, greater than unity, indicating that the interaction of PAHs in the mixture was less than additive. Exposure to UV radiation enhanced the toxic effects of fluoranthene and pyrene, but did not affect the toxicity of acenaphthene and phenanthrene. Effects of UV radiation on the toxicity of the mixture of four PAHs could be explained by the photoactivation of fluoranthene and pyrene alone. These results are consistent with predictions based on photophysical properties of PAH compounds.

Toxicity of sediment-associated PAHs to an estuarine copepod: Effects on survival, feeding, reproduction and behavior

The toxicities of sediment-associated phenanthrene, fluoranthene and diesel fuel to the estuarine copepod Schizopera knabeni Lang were investigated. The 4-d LC 50 was lowest for diesel fuel (194 μg/dry g), followed by phenanthrene (473 μg/dry g) and fluoranthene (> 2,100 μg/dry g). Sublethal effects on grazing rate were assessed in 30 h exposures using 14C-labeled microalgae. Feeding was inhibited at concentrations well below the 96 h LC 50 values (50% decrease at concentrations ranging from 48 to 94 μg/dry g), probably due to the narcotizing effect of PAH. PAH effects on offspring production were examined by exposing individual copulating pairs to sediment treatments for 14 d. No significant effect on clutch size was observed; however, PAHs decreased nauplii and copepodite production at sublethal sediment concentrations (50% decrease at concentrations ranging from 38 to 64 μg/dry g). Schizopera knabeni actively detected and avoided PAH-amended sediment, as determined in preference/avoidance experiments. Although mortality only occurs at exceedingly high concentrations, PAH sublethal effects will likely reduce fitness and alter S. knabeni distribution and abundance in heavily contaminated sites.

Effects of sediment-associated phenanthrene on survival, development and reproduction of two species of meiobenthic copepods

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 151:91-102 (1997) - doi:10.3354/meps151091 Effects of sediment-associated phenanthrene on survival, development and reproduction of two species of meiobenthic copepods Lotufo GR, Fleeger JW The lethal and sublethal toxicity of phenanthrene (a polycyclic aromatic hydrocarbon, PAH) to 2 species of meiobenthic estuarine harpacticoid copepods (Schizopera knabeni and Nitocra lacustris) was investigated. Individuals of different life stages (nauplius, copepodite, adult male and female) were exposed to sediment-associated phenanthrene in separate 10 d bioassays. Overall, N. lacustris (10 d LC50 valuesranging from 43 to 105 µg g-1 dry wt) was more sensitive than S. knabeni (10 d LC50 valuesranging from 84 to 349 µg g-1 dry wt). Significant differences in life-stage-specific sensitivity were observed for S. knabeni, with the nauplii being most sensitive, followed by copepodites, and adults; adult males and females were equally sensitive. For N. lacustris, females were significantly more sensitive than all other stages; no significant differences were evident among the other stages. Phenanthrene effects on offspring production were investigated in the adult 10 d bioassay. Significant decreases in offspring production occurred at sublethal concentrations for S. knabeni (as low as 22 µg g-1 dry wt), but at concentrations in the same range as the 10 d LC50 values for N. lacustris. In addition, phenanthrene significantly prolonged embryonic and larval development and decreased egg hatching success for both species. Our results suggest that PAHs have a negative effect on the reproduction of meiobenthic copepods at sublethal concentrations mostly due to a decrease in brood production rate and impairment of hatching. Overall, deleterious effects were manifested in the same range of concentrations for both species, but definite species-specific differences in the pattern of responses were evident. Sediment toxicity · Copepod · Life history · Meiobenthos · Phenanthrene Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 151. Publication date: May 22, 1997 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1997 Inter-Research.

Toxicity of sediment-associated pyrene and phenanthrene toLimnodrilus hoffmeisteri(oligochaeta: Tubificidae)

Acute and sublethal toxicities of sediment-spiked pyrene and phenanthrene to Limnodrilus hoffmeisteri Cleparede were investigated. Phenanthrene was acutely toxic at high sediment concentrations (10-d median lethal concentration of 297.5 {micro}g g{sup {minus}1}; 252.2--348.3, 95% confidence interval [Cl]). Pyrene was not acutely toxic, even at concentrations as high as 841 {micro}g g{sup {minus}1}. A significant impact of pyrene and phenanthrene on the feeding activity of L. hoffmeisteri was demonstrated through daily collection of egested fecal material during 5- and 10-d experiments. A short (5-d) exposure detected toxic effects more efficiently than a 10-d exposure, yielding IC25 values (estimated concentration causing a 25% reduction of measured endpoint in relation to the control[s]) of 58.9 {micro}g g{sup {minus}1} (32.1--89.4, 95% CI) for pyrene and 28.4 {micro}g g{sup {minus}1} (10.0--41.3, 95% CI) for phenanthrene. Effects on burrowing behavior and reproduction were assessed in a 28-d sediment exposure. Low burrowing avoidance (< 25%) was detected in high phenanthrene concentrations (143--612 {micro}g g{sup {minus}1}) but was not detected with pyrene. Offspring production was significantly reduced in dosed sediments yielding IC25 values of 59.1 {micro}g g{sup {minus}1} (38.3--112.5, 95% CI) for pyrene and 40.5 {micro}g g{sup {minus}1} (12.1--165.5, 955 CI) for phenanthrene. Decreases in egestion rates inmore » the presence of nonpolar contaminants should be quantified when investigating the effects of bioturbation by deposit feeders on the flux of contaminants from sediment into the water column.« less

Impacts of UV radiation and photomodification on the toxicity of pahs to the higher plant Lemna gibba (duckweed

AbstractThe toxicity of polycyclic aromatic hydrocarbons (PAHs) can be enhanced by both biotic and abiotic processes. This is exemplified by light, which, by virtue of the extensive π‐orbital systems of PAHs, can be a major factor in PAH toxicity. Light activation of PAHs is known to occur via photosensitization reactions (generation of singlet oxygen and superoxide) and potentially by photomodification of the chemicals (photooxidation and/or photolysis) to more toxic species. To examine the modes of PAH action in the light and determine if the photomodified compounds are hazardous, we investigated the photoinduced toxicity of anthracene, phenanthrene and benzo[a]pyrene to the aquatic higher plant Lemna gibba (a duckweed). Toxicity end points were inhibition of growth and extent of chlorosis. Light did indeed activate the phytotoxicity of PAHs, with UV radiation more effective than visible light. Dose‐response curves based on chemical concentration and light intensity revealed the order of phytotoxic strength to be anthracene &gt; phenanthrene &gt; benzo[a]pyrene. To explore whether photomodified PAHs were contributing to toxicity, the chemicals were irradiated before toxicity testing. The rates of photomodification of the three PAHs were rapid (half‐lives in hours), and the relative velocities were coincident with the order of toxic strength. Furthermore, the photomodified PAHs were more hazardous to Lemna than the intact compounds. Because interpretations of the potential impacts of PAHs in the environment are based mostly on measurements of the structurally intact chemicals, the severity of PAH hazards is possibly underestimated.