Biodegradation of nonylphenol in river sediment

Nonylphenol ethoxylate degradation in detergents during shelf time, a new exposure pathway, and a perspective on their substitution

Detergents are highly produced pollutants with environmental problems like foam generation and toxic effects in biota. Nonylphenol ethoxylates (NPEs) are efficient, economical, and versatile surfactants, used in detergents for more than 40 years due to their detergency capacity. In the environment, NPE biodegrades into the metabolite nonylphenol (NP), classified as an endocrine disruptor. The identification and quantification of 4-NP in a designed detergent and 30 commercially available detergents were performed to prove the degradation of NPE into 4-NP during storage time. This investigation introduces the first evidence of NPE degradation during storage in commercially available detergents, demonstrating a novel exposure pathway in humans that has not been explored before, representing potential human health risks. Therefore, simple, easy, low-cost, and available approaches to remove and substitute NP is paramount. Alkyl polyglucoside (APG) was assessed as a substitute, and the feasibility of this substitution was proven according to physical and chemical properties, cleaning performance, and antimicrobial properties. NPE substitution in detergents is demonstrated as a viable strategy to minimize exposure risks in humans and the environment.

Novel nonylphenol-degrading bacterial strains isolated from sewage sludge: Application in bioremediation of sludge

Nonylphenol (NP) is an anthropogenic pollutant frequently found in sewage sludge due to the insufficient degrading effectiveness of conventional WWTPs and has attracted attention as an endocrine disruptor. The aim of this study was to isolate specific NP-degrading bacteria from sewage sludge to be used in the degradation of this contaminant through bioaugmentation processes in aqueous solution and sewage sludge. Up to eight different bacterial strains were isolated, six of them not previously described as NP degraders. Bacillus safensis CN12 presented the best NP degradation in solution, and glucose used as an external carbon source increased its effect, reaching DT₅₀ degradation values (time to decline to half the initial concentration of the pollutant) of only 0.9 days and a complete degradation in <7 days. Four NP metabolites were identified throughout the biodegradation process, showing higher toxicity than the parent contaminant. In sewage sludge suspensions, the endogenous microbiota was capable of partially degrading NP, but a part remained adsorbed as bound residue. Bioaugmentation was used for the first time to remove NP from sewage sludge to obtain more environmentally friendly biosolids. However, B. safensis CN12 was not able to degrade NP due to its high adsorption on sludge, but the use of a cyclodextrin (HPBCD) as availability enhancer allowed us to extract NP and degrade it in solution. The addition of glucose as an external carbon source gave the best results since the metabolism of the sludge microbiota was activated, and HPBCD was able to remove NP from sewage sludge to the solution to be degraded by B. safensis CN12. These results indicate that B. safensis CN12 can be used to degrade NP in water and sewage sludge, but the method must be improved using consortia of B. safensis CN12 with other bacterial strains able to degrade the toxic metabolites produced.

A microcosm approach for evaluating the microbial nonylphenol and butyltin biodegradation and bacterial community shifts in co-contaminated bottom sediments from the Gulf of Finland, the Baltic Sea

Pollution of aquatic ecosystems with nonylphenol (NP) and butyltins (BuTs) is of great concern due to their effects on endocrine activity, toxicity to aquatic organisms, and extended persistence in sediments. The impact of contamination with NP and/or BuTs on the microbial community structure in marine sediments was investigated using microcosms and high-throughput sequencing. Sediment microcosms with NP (300 mg/kg) and/or BuTs (95 mg/kg) were constructed. Complete removal of monobutyltin (MBT) occurred in the microcosms after 240 days of incubation, while a residual NP rate was 40%. The content of toxic tributyltin (TBT) and dibutyltin (DBT) in the sediments did not change notably. Co-contamination of the sediments with NP and BuTs did not affect the processes of their degradation. The pollutants in the microcosms could have been biodegraded by autochthonous microorganisms. Significantly different and less diverse bacterial communities were observed in the contaminated sediments compared to non-contaminated control. Firmicutes and Gammaproteobacteria dominated in the NP treatment, Actinobacteria and Alphaproteobacteria in the BuT treatment, and Gammaproteobacteria, Alphaproteobacteria, Firmicutes, and Acidobacteria in the NP-BuT mixture treatment. The prevalence of microorganisms from the bacterial genera Halothiobacillus, Geothrix, Methanosarcina, Dyella, Parvibaculum, Pseudomonas, Proteiniclasticum, and bacteria affiliated with the order Rhizobiales may indicate their role in biodegradation of NP and BuTs in the co-contaminated sediments. This study can provide some new insights towards NP and BuT biodegradation and microbial ecology in NP-BuT co-contaminated environment.

Influence of physicochemical parameters on PPCP occurrences in the wetlands

There have been many global studies on the occurrence and distribution of pharmaceuticals and personal care products (PPCPs) in the aquatic resources, but reports on the effects of physicochemical properties of water on their concentrations are very scarce. The amounts and removal of these contaminants in various environmental media are dependent on these physicochemical properties, which include pH, temperature, electrical conductivity, salinity, turbidity, and dissolved oxygen. Here, we reviewed the influence of these properties on determination of PPCPs. Reports showed that increase in turbidity, electrical conductivity, and salinity gives increase in concentrations of PPCPs. Also, neutral pH gives higher PPCP concentrations, while decrease in temperature and dissolved oxygen gives low concentration of PPCPs. Nevertheless, it is quite challenging to ascertain the influence of water quality parameters on the PPCP concentration, as other factors like climate change, type of water, source of pollution, persistence, and dilution factor may have great influence on the concentration of PPCPs. Therefore, routine monitoring is suggested as most water quality parameters vary because of effects of climate change.

Degradation, transformation, and non-extractable residue formation of nitrated nonylphenol isomers in an oxic soil

Nitrated nonylphenols (NNPs) are main metabolites of the endocrine-disrupting nonylphenols in soil, yet their fate is unknown. Here, using four NNP isomers (NNP₁₁₁, NNP₁₁₂, NNP₆₅, and NNP₃₈), the degradation pattern of NNPs was investigated in an oxic soil for 266 days. Specifically, NNP₁₁₁ was ¹⁴C-labeled to facilitate investigating its degradation, transformation, and non-extractable residue (NER) formation. NNPs degradation was isomer-specific with the decreasing order of half-life: NNP₁₁₁ (126 days) > NNP₁₁₂ (76 days) > NNP₆₅ (14 days) > NNP₃₈ (8.4 days), providing direct evidence of the greater persistence of NNPs in soil than their parent NPs. At the end of the incubation, 8.5 %, 7.3 %, and 39.9 % of ¹⁴C-NNP₁₁₁ was mineralized, transformed to 2-amino-NP₁₁₁, and formed NERs in active soil, respectively. In contrast, NERs in sterilized soils were significantly lower, amounting to 15.1 % and 17.3 % in autoclaved and γ-irradiated soil, respectively. The majority of the NERs (>70 %) were in humin fraction, in which type I NER was the predominant (>90 %) mode for NER formation. Our results provide comprehensive knowledge on the fate of NNPs in soil, demonstrating that isomer-specific behavior, transformation products of NNPs, and NER formation should be considered when evaluating environmental fate and risks of NNPs.

Occurrence, potential ecological risks, and degradation of endocrine disrupter, nonylphenol, from the aqueous environment

Nonylphenol (NP) is considered a potential endocrine-disrupting chemical affecting humans and the environment. Due to widespread occurrence in the aquatic environment and neuro-, immuno, reproductive, and estrogenic effects, nonylphenol calls for considerable attention from the scientific community, researchers, government officials, and the public. It can persist in the environment, especially soil, for a long duration because of its high hydrophobic nature. Nonylphenol is incorporated into the water matrices via agricultural run-off, wastewater effluents, agricultural sources, and groundwater leakage from the soil. In this regard, assessment of the source, fate, toxic effect, and removal of nonylphenol seems a high-priority concern. Remediation of nonylphenol is possible through physicochemical and microbial methods. Microbial methods are widely used due to ecofriendly in nature. The microbial strains of the genera, Sphingomonas, Sphingobium, Pseudomonas, Pseudoxanthomonas, Thauera, Novosphingonium, Bacillus, Stenotrophomonas, Clostridium, Arthrobacter, Acidovorax, Maricurvus, Rhizobium, Corynebacterium, Rhodococcus, Burkholderia, Acinetobacter, Aspergillus, Pleurotus, Trametes, Clavariopsis, Candida, Phanerochaete, Bjerkandera, Mucor, Fusarium and Metarhizium have been reported for their potential role in the degradation of NP via its metabolic pathway. This study outlines the recent information on the occurrence, origin, and potential ecological and human-related risks of nonylphenol. The current development in the removal of nonylphenol from the environment using different methods is discussed. Despite the significant importance of nonylphenol and its effects on the environment, the number of studies in this area is limited. This review gives an in-depth understanding of NP occurrence, fate, toxicity, and remediation from the environments.

Occurrence, uptake, and health risk assessment of nonylphenol in soil-celery system simulating long-term reclaimed water irrigation

Reclaimed water (RW) irrigation provides an effective method to alleviate freshwater resources shortage. However, the residual endocrine disrupting chemicals in RW may cause potential risks to the environment and human body. Pot experiments were conducted to study the occurrence and environmental behavior of nonylphenol (NP) in soil-celery system simulating long-term RW irrigation, and exposure to NP was assessed to identify human health risks. Celery was grown on soil with different initial NP concentrations (0.126-22.9 mg·kg^-1) to simulate the different irrigation years. After harvest, the NP concentrations in roots, stems and leaves were 0.26-1.51, 0.21-0.45 and 0.33-0.74 mg·kg^-1, respectively. The NP concentrations in soil at depths of 5, 10 and 15 cm were 0.047-1.75, 0.088-1.77 and 0.048-1.07 mg·kg^-1, respectively. The results showed a limited NP enrichment capacity of celery and low residual rates of NP in soil-celery system, which were between 6.33% and 26.3%. Both the bioconcentration factors (BCFs) and the residual rates of NP decreased with the initial NP concentrations in soil. The total noncancer hazard quotients (HQs) for human exposure to NP from celery and soil had the order of 10^-4-10^-3, which was lower than the acceptable risk level of 1 and showed safe conditions under long-term RW irrigation.

Transformation of Illicit Drugs and Pharmaceuticals in Sewer Sediments

In-sewer stability of human excreted biomarkers is a critical factor of wastewater-based epidemiology in back-estimating illicit drug and pharmaceutical use in the community. Biomarker stability has been investigated in sewers with the presence of biofilms, but the understanding in sewer sediments is still lacking. This study for the first time employed a laboratory sediment reactor to measure 18 illicit drug and pharmaceutical biomarkers under gravity sewer environments with the presence of sediments. Biomarkers exhibited various stability patterns due to transformation processes occurring in the bulk wastewater and sediments. The attenuation of a biomarker by sediments is driven by complex processes involving biodegradation, diffusion, and sorption, which is directly proportional to the ratio of sediment surface area against wastewater volume. The sediment-driven transformation coefficients of biomarkers are higher than the accordingly biofilm-mediated rates because of stronger microbial activities in sediments. Additionally, the stability of most biomarkers was insensitive to the natural pH variation in sewers, except for a few compounds (e.g., methadone, ketamine, and paracetamol) susceptible to pH changes. In general, this study delineates the stability data of various biomarkers in gravity sewers with sediments, which are novel and long-missing information for wastewater-based epidemiology and improve the reliability of back-estimation in complex sewer networks.

Occurrence, fate and toxic effects of the industrial endocrine disrupter, nonylphenol, on plants - A review

Nonylphenol (NP) and its detrimental effects on the environment, humans, wildlife, fish and birds is an increasingly important global research focus. The number of investigations on the toxicity and metabolic fate of NP in plants is however limited. This paper reviews the prevalence and source of NP in plants and the effect it has on its morphological, physiological and ultrastructural status. Fruit and vegetables have been found to contain levels of NP that is twenty-fold exceeding the no observable effect level (NOEL) of freshwater algae. Apart from the potential risk this poses to the health of consumers, it can overburden the plant's natural defence system, leading to growth disorders. Plants exposed to NP show signs of overall growth reduction, changes in organelle structure and oxidative damage. These adverse effects may exacerbate the food security dilemma faced by many countries and impede their progress towards attaining the sustainable development goals.

Adsorption and degradation in the removal of nonylphenol from water by cells immobilized on biochar

To investigate the role of adsorption by biochar and biodegradation by bacteria in the wastewater treatment system of microorganisms immobilized on biochar, Nonylphenol (NP) removal (adsorption + degradation) rates and degradation rates from water by NP degrading bacteria immobilized on bamboo charcoal (BC) and wood charcoal (WC) were examined in a short-term and long-term. Results showed that cells immobilized on different biochar had different NP removal effects, and cells immobilized on bamboo charcoal (I-BC) was better. After eight rounds of long-term reuse, the cumulative removal rate and the degradation rate of NP in water by I-BC were 93.95% and 41.86%, respectively, significantly higher than those of cells immobilized on wood charcoal (69.60%, 22.78%) and free cells (64.79%, 19.49%) (P < 0.01). The rise in the ratio of the degradation rate to the removal rate indicated that the long-term NP removal effect is more dependent on biodegradation. The amount of residual NP in I-BC still accounted for about 50%, indicating that the secondary pollution in the disposal of carrier could not be ignored. In addition, promotion effect of biochar on microorganisms were observed by SEM, quantitative PCR and 16S rRNA. Pseudomonas, Achromobacter, Ochrobactrum and Stenotrophomonas were predominant bacteria for NP degradation. The addition of biochar (especially bamboo charcoal) also effectively delayed the transformation of their community structure.

Treatment of 17α‑ethinylestradiol, 4‑nonylphenol, and carbamazepine in wastewater using an aerobic granular sludge sequencing batch reactor

This study quantifies the removal of a mixture of commonly detected emerging contaminants, 17α‑ethinylestradiol (EE2), 4‑nonylphenol (NP), and carbamazepine (CBZ) from synthetic wastewater using aerobic granular sludge in a sequential batch reactor. The emerging contaminant concentration in the influent wastewater was maintained near 500 μg/L for the duration of the experiment. Removal of EE2, NP, and CBZ is comprised of both adsorption and degradation. In general, the main removal mechanism for the emerging contaminants was initially adsorption, however it transitions to degradation as the adsorption capacity is saturated. The stabilized degradation for EE2 and NP in the SBR, was 16.09 μg/g and 20.05 μg/g, respectively. There was limited degradation of CBZ during the anaerobic phase. Both the Langmuir and Freundlich adsorption isotherms fit the data well and constants for the equations are calculated. The constants for the Langmuir Isotherm are found to be (X/m)_max = 36.23, b = 0.0019 for EE2 and (X/m)_max = 44.25, b = 0.0004 for CBZ. None of the tested compounds were found to be detrimental to the performance of the aerobic granules, and high macronutrient removal efficiency was maintained. The granule sludge bed and particle size were not negatively affected by EE2 and NP, however, carbamazepine appeared to interfere with the mechanism of granule formation resulting in a decrease in particle size during the experiment.

An integrated modelling framework and a modified method for evaluating non-carcinogenic health risks from nonylphenol-contaminated food consumption in Long An, Vietnam

This study proposed an integrated modelling framework and a modified method for evaluating non-carcinogenic health risks from nonylphenol (NP)-contaminated food consumption. First, a fugacity-based multimedia model and a food web bioaccumulation model were adopted to predict the distribution of NP in the Can Giuoc river and the bioaccumulative concentrations in biota. Next, local people's exposure to NP was quantified using the accumulative concentrations and the data of fishery products intake from a questionnaire survey distributed among 203 local people. Then, human health risk was evaluated in terms of fishery products intake and intake frequency which were each derived from the same survey. The study revealed that human health risk would exist, although the obtained bioaccumulation factors for the consumed organisms were lower than the bioaccumulation criteria. Consuming 141 g or more per serving of riverine food products resulted in an average NP intake exceeding 0.005 mg/kg of body weight per day among 45-73% of the local adults, of whom pregnant women or young and potential mothers accounted for 10-21%. Seventy-nine percent was the highest rate of the population to be at risk under medium river flow rate when food-intake amount and intake frequency were taken into account. Ingesting 70 g per serving of more contaminated species, such as whiteleg shrimp and small fish, less frequently could lead to less risk exposure than ingesting 267 g per serving of less contaminated species, such as sand goby and climbing pearch, more frequently. By coupling food intake with intake frequency, the modified method enables the studying of human health risk from NP-contaminated food consumption to be conducted with more care, and so benefits risk communication at local level.

Role of biochar in biodegradation of nonylphenol in sediment: Increasing microbial activity versus decreasing bioavailability

The observed strong sorption of hydrophobic organic contaminants (HOCs) to biochar presents potential implications for HOCs bioavailability and bioaccessibility in sediments, while biochar could impact sediment microbial ecology. However, the comprehensive study on the effects of biochar on HOC biodegradation coupled with bioavailability and microbial ecology are rarely documented. In this paper, the effects of biochar on the biodegradation of nonylphenol (NP) were investigated using 3 different NP concentrations (20, 50 and 500 mg/Kg) in sediments amended with different percentage of rice straw biochar (RC). Results showed that the influence of RC on NP biodegradation varied with different NP concentrations. At low NP concentrations, RC suppressed NP biodegradation by reducing NP bioavailability, while at high NP concentrations, moderate RC addition promoted biodegradation by reducing toxicity of NP to microbes. The effects of NP on microbial community structures were significant (P < 0.01), but those of RC were not significant (P > 0.05). The RC affected microorganisms through altering NP toxicity, microbial quantity and activity, but not microbial community structures. This study indicated that there could be an optimal biochar percentage in biochar-sediment systems at different HOC concentrations, which strengthened HOC biodegradation process and accelerated biodegradation rate, forming adsorption-biodegradation coupled bioremediation.

Nonylphenol biodegradation characterizations and bacterial composition analysis of an effective consortium NP-M2

Nonylphenol (NP), ubiquitously detected as the degradation product of nonionic surfactants nonylphenol polyethoxylates, has been reported as an endocrine disrupter. However, most pure microorganisms can degrade only limited species of NP with low degradation efficiencies. To establish a microbial consortium that can effectively degrade different forms of NP, in this study, we isolated a facultative microbial consortium NP-M2 and characterized the biodegradation of NP by it. NP-M2 could degrade 75.61% and 89.75% of 1000 mg/L NP within 48 h and 8 days, respectively; an efficiency higher than that of any other consortium or pure microorganism reported so far. The addition of yeast extract promoted the biodegradation more significantly than that of glucose. Moreover, surface-active compounds secreted into the extracellular environment were hypothesized to promote high-efficiency metabolism of NP. The detoxification of NP by this consortium was determined. The degradation pathway was hypothesized to be initiated by oxidization of the benzene ring, followed by step-wise side-chain biodegradation. The bacterial composition of NP-M2 was determined using 16S rDNA library, and the consortium was found to mainly comprise members of the Sphingomonas, Pseudomonas, Alicycliphilus, and Acidovorax genera, with the former two accounting for 86.86% of the consortium. The high degradation efficiency of NP-M2 indicated that it could be a promising candidate for NP bioremediation in situ.

Composting of 4-nonylphenol-contaminated river sediment with inocula of Phanerochaete chrysosporium

A composting study was performed to investigate the degradation of 4-nonylphenol (4-NP) in river sediment by inoculating Phanerochaete chrysosporium (Pc). Pc was inoculated into composting Reactor A, C and D, while Reactor B without inocula was used as control. The results showed that composting with Pc accelerated the degradation of 4-NP, increased the catalase and polyphenol oxidase enzyme activities in contaminated sediment. The dissipation half-life (t_1/2) of 4-NP in Reactor A, C and D with inocula of Pc were 2.079, 2.558, 2.424days, while in Reactor B without inocula of Pc it was 3.239days, respectively. Correlation analysis showed that the contents of 4-NP in sediment in Reactor A and D were negatively correlated with the actives of laccase, whereas no obvious correlation was observed in Reactor B and C. All these findings also indicated that Pc enhanced the maturity of compost, and the best composting C/N ratio was 25.46:1.

Spatial and temporal variability in the potential of river water biofilms to degrade p-nitrophenol

In order to predict the fate of chemicals in the environment, a range of regulatory tests are performed with microbial inocula collected from environmental compartments to investigate the potential for biodegradation. The abundance and distribution of microbes in the environment is affected by a range of variables, hence diversity and biomass of inocula used in biodegradation tests can be highly variable in space and time. The use of artificial or natural biofilms in regulatory tests could enable more consistent microbial communities be used as inocula, in order to increase test consistency. We investigated spatial and temporal variation in composition, biomass and chemical biodegradation potential of bacterial biofilms formed in river water. Sampling time and sampling location impacted the capacity of biofilms to degrade p-nitrophenol (PNP). Biofilm bacterial community structure varied across sampling times, but was not affected by sampling location. Degradation of PNP was associated with increased relative abundance of Pseudomonas syringae. Partitioning of the bacterial metacommunity into core and satellite taxa revealed that the P. syringae could be either a satellite or core member of the community across sampling times, but this had no impact on PNP degradation. Quantitative PCR analysis of the pnpA gene showed that it was present in all samples irrespective of their ability to degrade PNP. River biofilms showed seasonal variation in biomass, microbial community composition and PNP biodegradation potential, which resulted in inconsistent biodegradation test results. We discuss the results in the context of the mechanisms underlying variation in regulatory chemical degradation tests.

First comprehensive screening of lipophilic organic contaminants in surface waters of the megacity Jakarta, Indonesia

Jakarta is an Indonesian coastal megacity with over 10 million inhabitants. The rivers flowing through the city receive enormous amounts of untreated wastewaters and discharge their pollutant loads into Jakarta Bay. We utilized a screening approach to identify those site-specific compounds that represent the major contamination of the cities' water resources, and detected a total number of 71 organic contaminants in Jakarta river water samples. Especially contaminants originating from municipal wastewater discharges were detected in high concentrations, including flame retardants, personal care products and pharmaceutical drugs. A flame retardant, a synthetic fragrance and caffeine were used as marker compounds to trace the riverine transport of municipal wastewaters into Jakarta Bay. These markers are also appropriate to trace municipal wastewater discharges to other tropical coastal ecosystems. This application is in particular useful to evaluate wastewater inputs from land-based sources to habitats which are sensitive to changing water quality, like coral reefs.

Contributions of Abiotic and Biotic Processes to the Aerobic Removal of Phenolic Endocrine-Disrupting Chemicals in a Simulated Estuarine Aquatic Environment

The contributions of abiotic and biotic processes in an estuarine aquatic environment to the removal of four phenolic endocrine-disrupting chemicals (EDCs) were evaluated through simulated batch reactors containing water-only or water-sediment collected from an estuary in South China. More than 90% of the free forms of all four spiked EDCs were removed from these reactors at the end of 28 days under aerobic conditions, with the half-life of 17α-ethynylestradiol (EE2) longer than those of propylparaben (PP), nonylphenol (NP) and 17β-estradiol (E2). The interaction with dissolved oxygen contributed to NP removal and was enhanced by aeration. The PP and E2 removal was positively influenced by adsorption on suspended particles initially, whereas abiotic transformation by estuarine-dissolved matter contributed to their complete removal. Biotic processes, including degradation by active aquatic microorganisms, had significant effects on the removal of EE2. Sedimentary inorganic and organic matter posed a positive effect only when EE2 biodegradation was inhibited. Estrone (E1), the oxidizing product of E2, was detected, proving that E2 was removed by the naturally occurring oxidizers in the estuarine water matrixes. These results revealed that the estuarine aquatic environment was effective in removing free EDCs, and the contributions of abiotic and biotic processes to their removal were compound specific.

Impact of composting strategies on the degradation of nonylphenol in sewage sludge

Nonylphenol can be present in sewage sludge, and this can limit the use of the sewage sludge to amend soil. Composting is one of the most efficient and economical methods of making sewage sludge stable and harmless. The nonylphenol degradation rates during composting with added bulking agents and with aeration applied were studied. Three organic bulking agents (sawdust, corn stalk, and mushroom residue) were added to sewage sludge, and the effects of the bulking agents used and the amount added on nonylphenol degradation were determined. The highest apparent nonylphenol degradation rate (71.6%) was found for sewage sludge containing 20% mushroom residue. The lowest apparent nonylphenol degradation rate (22.5%) was found for sewage sludge containing 20% sawdust. The temperature of the composting pile of sewage sludge containing 20% sawdust became too high for nonylphenol to be efficiently degraded, and the apparent nonylphenol degradation rate was lower than was found for sewage sludge containing 10% sawdust. Increasing the ventilating time from 5 to 15 min increased the apparent nonylphenol degradation rate from 19.7 to 41.6%. Using appropriate aerobic conditions facilitates the degradation of nonylphenol in sewage sludge, decreasing the risks posed by sewage sludge applied to land. Adding too much of a bulking agent can decrease the amount of the nonylphenol degraded. Increasing the ventilating time and the amount of air supplied can increase the amount of nonylphenol degraded even if doing so causes the composting pile temperature to remain low.

Anaerobic biodegradation of nonylphenol in river sediment under nitrate- or sulfate-reducing conditions and associated bacterial community

Nonylphenol (NP) is a commonly detected pollutant in aquatic ecosystem and can be harmful to aquatic organisms. Anaerobic degradation is of great importance for the clean-up of NP in sediment. However, information on anaerobic NP biodegradation in the environment is still very limited. The present study investigated the shift in bacterial community structure associated with NP degradation in river sediment microcosms under nitrate- or sulfate-reducing conditions. Nearly 80% of NP (100 mg kg(-1)) could be removed under these two anaerobic conditions after 90 or 110 days' incubation. Illumina MiSeq sequencing analysis indicated that Proteobacteria, Firmicutes, Bacteroidetes and Chloroflexi became the dominant phylum groups with NP biodegradation. The proportion of Gammaproteobacteria, Deltaproteobacteria and Choloroflexi showed a marked increase in nitrate-reducing microcosm, while Gammaproteobacteria and Firmicutes in sulfate-reducing microcosm. Moreover, sediment bacterial diversity changed with NP biodegradation, which was dependent on type of electron acceptor.

Variation of nonylphenol-degrading gene abundance and bacterial community structure in bioaugmented sediment microcosm

Nonylphenol (NP) can accumulate in river sediment. Bioaugmentation is an attractive option to dissipate heavy NP pollution in river sediment. In this study, two NP degraders were isolated from crude oil-polluted soil and river sediment. Microcosms were constructed to test their ability to degrade NP in river sediment. The shift in the proportion of NP-degrading genes and bacterial community structure in sediment microcosms were characterized using quantitative PCR assay and terminal restriction fragment length polymorphism analysis, respectively. Phylogenetic analysis indicated that the soil isolate belonged to genus Stenotrophomonas, while the sediment isolate was a Sphingobium species. Both of them could almost completely clean up a high level of NP in river sediment (150 mg/kg NP) in 10 or 14 days after inoculation. An increase in the proportion of alkB and sMO genes was observed in sediment microcosms inoculated with Stenotrophomonas strain Y1 and Sphingobium strain Y2, respectively. Moreover, bioaugmentation using Sphingobium strain Y2 could have a strong impact on sediment bacterial community structure, while inoculation of Stenotrophomonas strain Y1 illustrated a weak impact. This study can provide some new insights towards NP biodegradation and bioremediation.

Nonylphenol biodegradation in river sediment and associated shifts in community structures of bacteria and ammonia-oxidizing microorganisms

Nonylphenol (NP) is one of commonly detected contaminants in the environment. Biological degradation is mainly responsible for remediation of NP-contaminated site. Knowledge about the structure of NP-degrading microbial community is still very limited. Microcosms were constructed to investigate the structure of microbial community in NP-contaminated river sediment and its change with NP biodegradation. A high level of NP was significantly dissipated in 6-9 days. Bacteria and ammonia-oxidizing archaea (AOA) were more responsive to NP amendment compared to ammonia-oxidizing bacteria (AOB). Gammaproteobacteria, Alphaproteobacteria and Bacteroidetes were the largest bacterial groups in NP-degrading sediment. Microorganisms from bacterial genera Brevundimonas, Flavobacterium, Lysobacter and Rhodobacter might be involved in NP degradation in river sediment. This study provides some new insights towards NP biodegradation and microbial ecology in NP-contaminated environment.

Isomer-specific biodegradation of nonylphenol in river sediments and structure-biodegradability relationship

Nonylphenol (NP), a well-known environmental estrogen with numerous isomers, is frequently found in surface water and sediments. Recent studies showed that NP isomers exhibited different estrogenicity. However, at present little information is available on its isomer-specific degradation in the bed sediment, which is the primary sink of NP in surface aquatic systems. In this study, we investigated the biodegradability of 19 NP isomers in two river sediments under oxic and anoxic conditions. Under oxic conditions, the half-lives of NP isomers in an upper river sediment ranged from 0.9 to 13.2 d. Under reduced conditions, the persistence of NP isomers generally increased, with negligible dissipation under strongly reduced conditions. In the well-aerated sediment, NP isomers with short side chain and/or bulky α-substituents were found to be more recalcitrant to degradation. Moreover, when a total of 57 molecular descriptors were examined, the degree of branching as quantified by IDWbar was found to result in the best linear correlation with half-lives of NP isomers (R(2) = 0.88). These results indicated that the isomer-specificity of NP in environmental processes should be considered, and that simple molecular descriptors may be used to identify the more recalcitrant isomers, thus allowing prioritization in the evaluation of environmental fate and risks of NP isomers.

The bioconcentration and degradation of nonylphenol and nonylphenol polyethoxylates by Chlorella vulgaris

Nonylphenol polyethoxylates (NPnEOs), a major class of nonionic surfactants, can easily enter into aquatic environments through various pathways due to their wide applications, which leads to the extensive existence of their relative stable metabolites, namely nonylphenol (NP) and mono- to tri-ethoxylates. This study investigated the bioconcentration and degradation of NP and NPnEO oligomers (n = 1–12) by a green algae, Chlorella vulgaris. Experimental results showed that C. vulgaris can remove NP from water phase efficiently, and bioconcentration and degradation accounted for approximately half of its loss, respectively, with a 48 h BCF (bioconcentration factor) of 2.42 × 10³. Moreover, C. vulgaris could concentrate and degrade NPnEOs, distribution profiles of the series homologues of the NPnEOs in algae and water phase were quite different from the initial homologue profile. The 48 h BCF of the NPnEO homologues increased with the length of the EO chain. Degradation extent of total NPnEOs by C. vulgaris was 95.7%, and only 1.1% remained in water phase, and the other 3.2% remained in the algal cells. The algae removed the NPnEOs mainly through degradation. Due to rapid degradation, concentrations of the long chain NPnEO homologous in both water (n ≥ 2) and the algal phase (n ≥ 5) was quite low at the end of a 48 h experiment.

Effects of sterile storage, cation saturation and substrate additions on the degradability and extractability of nonylphenol and phenanthrene in soil

The main objective of this study was to determine the effects of long-term abiotic processes during aging of organic pollutants in soil on their microbial degradability and formation of non-extractable residues. The specific aims of our study were to investigate how the fate of p353-nonylphenol (NP) and phenanthrene (Phe) in soils might be affected by: (i) saturation of soil by cations with different valency (Na(+), Ca(2+) or Al(3+)), (ii) addition of organic substrate (wood flour) during incubation period and (iii) different soil moisture levels. This study showed positive effect of long-term aging of sterilized samples on respiration of re-inoculated samples. However, the lack of aging effects on the mineralization of NP and Phe indicates that slow sorption processes by diffusion into less bioaccessible domains were not relevant in studied soils. Similarly, the lower respiration and xenobiotic mineralization rates in the Na(+) and Al(3+) treated soils indicate that this is due to toxic effects on microbial activity and not due to xenobiotic accessibility. Instead, the formation of non-extractable residues was strongly promoted by biological activity, most likely through formation of more reactive metabolites. The addition of wood flour greatly stimulated microbial respiration and enhanced NP mineralization while inhibiting that of Phe. Along with negligible effect of water addition after 4 weeks of incubation on kinetics of soil respiration, the soil moisture effect on xenobiotics mineralization indicates that most probably the bioavailability of NP and Phe increased due to bridging role of water films in soil.

Toxicity of the xenoestrogen nonylphenol and its biodegradation by the alga Cyclotella caspia

Alkylphenols (APs), the breakdown products of alkylphenol polyethoxylates that are widely used as surfactants, have been proven to exert estrogenic effects. With industrial development, higher concentrations of APs are discharged into aquatic environments. Nonylphenol (NP), the most noxious AP, is included in the blacklist of several countries. The toxicity of NP to the alga Cyclotella caspia and the biodegradation of NP by C. caspia were studied in the laboratory. The median effective concentration at 96 hr (96 hr EC50) of NP for C. caspia was found to be 0.18 mg/L. Five toxicity and three degradation indices were selected for toxicity and biodegradation experiments, respectively, in five or three concentrations of NP set by the 96 hr EC50 of NP. The algal growth rate and chlorophyll a contents decreased as NP concentration increased. The main manifestations of morphological deformity of the cells included volume expansion and the presence of cytoplasmic inclusions (lipid droplets). The abnormality rate of the cells increased with NP concentration and time, and was 100% at 0.22 and 0.26 mg/L of NP after 192 hr of culture. Superoxide dismutase activity initially increased and then declined at a higher NP toxicity of greater than 0.18 mg/L. After 192 hr of culture, the biodegradation rates of NP by C. caspia with initial concentrations of 0.14, 0.18, and 0.22 mg/L were 37.7%, 31.7%, and 6.5%, respectively. The kinetic equation of C. caspia biodegradation on NP was correlated with algal growth rate and initial NP concentration.

The potential role of water quality parameters on occurrence of nonylphenol and bisphenol A and identification of their discharge sources in the river ecosystems

Nonylphenol (NP) and bisphenol A (BPA) have attracted great attention due to their estrongenic activities and occurrence in different environments. This study investigated concentrations of NP and BPA in water and sediments of 16 major rivers in Taiwan to determine their association with water quality parameters on their distribution. The sources of NP and BPA discharged into river environments were also identified. The results showed that concentrations of NP and BPA were in the range of 0.02-3.94 and 0.01-44.65μgL(-1) in water and 6.59-47797.69 and 0.37-491.54μgkg(-1) dry weight in sediments. High levels of NP and BPA in water and sediments were measured in sampling sites near highly industrialized and urbanized areas. Construction of the sewage system and wastewater treatment plant has decreased these chemicals discharged into Love River. Dilution effects and erosion of surface sediments in the high-flow season resulted in lower concentrations of NP and BPA detected in sediments of most rivers than those in the low-flow season. Occurrence characteristics of NP and BPA in water and sediments were mainly related to organic carbon contents in sediments and several water quality parameters such as dissolved oxygen, pH, concentrations of ammonia-nitrogen and total organic carbon in water. Effluents from NP/BPA-related factories appeared to be the major discharge sources of NP and BPA. Use and waste of BPA-containing products in household activity was the another discharge source of BPA, but handling NP-containing products became an important source of NP only in the low-flow season.

Aerobic degradation of tetrabromobisphenol-A by microbes in river sediment

This study investigated the aerobic degradation of tetrabromobisphenol-A (TBBPA) and changes in the microbial community in river sediment from southern Taiwan. Aerobic degradation rate constants (k(1)) and half-lives (t(1/2)) for TBBPA (50 μg g(-1)) ranged from 0.053 to 0.077 d(-1) and 9.0 to 13.1 d, respectively. The degradation of TBBPA (50 μg g(-1)) was enhanced by adding yeast extract (5 mg L(-1)), sodium chloride (10 ppt), cellulose (0.96 mg L(-1)), humic acid (0.5 g L(-1)), brij 30 (55 μM), brij 35 (91 μM), rhamnolipid (130 mg L(-1)), or surfactin (43 mg L(-1)), with rhamnolipid yielding a higher TBBPA degradation than the other additives. For different toxic chemicals in the sediment, the results showed the high-to-low order of degradation rates were bisphenol-A (BPA) (50 μg g(-1))>nonylphenol (NP) (50 μg g(-1))>4,4'-dibrominated diphenyl ether (BDE-15) (50 μg g(-1))>TBBPA (50 μg g(-1))>2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209) (50 μg g(-1)). The addition of various treatments changed the microbial community in river sediments. The results also showed that Bacillus pumilus and Rhodococcus ruber were the dominant bacteria in the process of TBBPA degradation in the river sediments.

Occurrence and biodegradation of nonylphenol in the environment

Nonylphenol (NP) is an ultimate degradation product of nonylphenol polyethoxylates (NPE) that is primarily used in cleaning and industrial processes. Its widespread use has led to the wide existence of NP in various environmental matrices, such as water, sediment, air and soil. NP can be decreased by biodegradation through the action of microorganisms under aerobic or anaerobic conditions. Half-lives of biodegradation ranged from a few days to almost one hundred days. The degradation rate for NP was influenced by temperature, pH and additions of yeast extracts, surfactants, aluminum sulfate, acetate, pyruvate, lactate, manganese dioxide, ferric chloride, sodium chloride, hydrogen peroxide, heavy metals, and phthalic acid esters. Although NP is present at low concentrations in the environment, as an endocrine disruptor the risks of long-term exposure to low concentrations remain largely unknown. This paper reviews the occurrence of NP in the environment and its aerobic and anaerobic biodegradation in natural environments and sewage treatment plants, which is essential for assessing the potential risk associated with low level exposure to NP and other endocrine disruptors.

Temporal variation of pharmaceuticals in an urban and agriculturally influenced stream

Pharmaceuticals have become ubiquitous in the aquatic environment. Previous studies consistently demonstrate the prevalence of pharmaceuticals in freshwater but we do not yet know how concentrations vary over time within a given system. Two sites in central Indiana with varying land use in the surrounding watershed (suburban and agricultural) were sampled monthly for pharmaceutical concentrations and stream physiochemical parameters. Sediment samples were also collected at each sampling event for measurement of δ(15)N natural abundance and sediment organic content. Across sites and sampling events, twelve pharmaceuticals were detected including acetaminophen, caffeine, carbamazepine, cotinine, N,N-diethyl-meta-toluamide (DEET), gemfibrozil, ibuprofen, sulfadimethoxine, sulfamethazine, sulfamethoxazole, triclosan, and trimethoprim. Sulfathiazole, lincomycin, and tylosin were not detected at either site at any time. The agriculturally-influenced site had comparable pharmaceutical concentrations to the urban-influenced site. In general, pharmaceutical concentrations increased during winter at both sites and decreased during spring and summer. Multiple regression analyses indicated that water column dissolved oxygen, the number of days since precipitation, and solar radiation influenced total pharmaceutical concentration in the urban-influenced site; whereas pH, chlorophyll a concentration, and total amount of rainfall in the previous 10 days influenced total pharmaceutical concentrations in the agriculturally-influenced site. Pharmaceutical concentrations were not correlated with sediment δ(15)N across or within sites. However, sediment in the urban-influenced site had higher mean δ(15)N signatures relative to sediment in the agriculturally-influenced site. These data indicate pharmaceuticals are persistent in aquatic ecosystems influenced by both agricultural and suburban activity. Pharmaceuticals are designed to have a physiological effect; therefore, it is likely that they may also influence aquatic organisms, potentially threatening freshwater ecosystem health.

Biotransformation of halogenated nonylphenols with sphingobium xenophagum bayram and a nonylphenol-degrading soil-enrichment culture

When discharged in chlorinated wastewater, alkylphenol ethoxylate metabolites (APEMs) are often discharged in halogenated form (XAPEMs, X = Cl, or Br). The potential environmental impact of XAPEM release was assessed by studying the biotransformation of halogenated nonylphenol by Sphingobium xenophagum Bayram and a soil-enrichment culture. S. xenophagum Bayram transformed chlorinated nonylphenol (ClNP) slowly and nearly completely to form nonyl alcohol; the monobrominated nonylphenol (BrNP) and dibrominated nonylphenol were transformed cometabolically with nonylphenol (NP) as the primary substrate. The presence of either ClNP or BrNP in the S. xenophagum Bayram cultures retarded the transformation of nonhalogenated NP. NP-degrading soil cultures transformed nonhalogenated NP to a mixture of nonyl alcohols but were not capable of transforming either ClNP or BrNP. The presence of either ClNP or BrNP retarded the transformation of nonhalogenated NP in the soil cultures, as was observed in S. xenophagum Bayram cultures. Predicting the environmental fate of alkylphenol ethoxylate residues requires considering APEM halogenation during effluent chlorination and inhibitory effects as well as the refractory nature of halogenated metabolites.

Biodegradation of bisphenol-A in river sediment

This research investigated the aerobic and anaerobic degradation of bisphenol-A (BPA) in river sediment. With the addition of 250 μg g⁻¹ BPA, the percentages of BPA remaining in sediment from sites A, B, and C were 21.9 %, 3.5 % and 12.5 %, respectively, after 5 days of incubation under aerobic conditions; degradation was not significant after 140 days of incubation under anaerobic conditions. The aerobic degradation of BPA was enhanced by adding yeast extract (5 mg L⁻¹), sodium chloride (1 %), cellulose (0.96 mg L⁻¹), brij 30 (55 μM), brij 35 (91 μM), rhamnolipid (130 mg L⁻¹), or surfactin (43 mg L⁻¹), with rhamnolipid yielding higher BPA degradation than the other additives. 2,4-bis (1,1-dimethyl ethyl) phenol, an intermediate product resulting from the aerobic degradation of BPA was accumulated in sediments. Of the bacterial strains isolated from the sediment, strains J1, J2, J3, and J4 expressed the best aerobic degrading ability. The highest BPA degradation rate was found in the sediment by the addition of strains J1, J2, J3, and J4 combined, whereas the sediment without the addition of the 4 strains had the lowest biodegradation rate. This research offers feasible methods for the removal of BPA in river sediment for bioremediation.

Biodegradation of tetrachlorobisphenol-A in river sediment and the microbial community changes

This study investigated the aerobic degradation of tetrachlorobisphenol-A (TCBPA) in sediment samples collected at three sites along Erren River in southern Taiwan. TCBPA biodegradation rate constants (k(1)) and half-lives (t(1/2)) ranged from 0.03 to 0.06 day(-1) and 11.6 to 23.1 days, respectively. The biodegradation of TCBPA was enhanced by the addition of cellulose, yeast extract, sodium chloride, brij 30, brij 35, surfactin, and rhamnolipid. Of the micro-organism strains isolated from the sediment, we found that strains L1 and L5 (identified as Bacillus megaterium and Pseudomonas putida) expressed the best biodegrading ability. The inoculation of sediment with the TCBPA-degrading bacteria could enhance the efficiency of degradation.

Aerobic nonylphenol degradation and nitro-nonylphenol formation by microbial cultures from sediments

Nonylphenol (NP) is an estrogenic pollutant which is widely present in the aquatic environment. Biodegradation of NP can reduce the toxicological risk. In this study, aerobic biodegradation of NP in river sediment was investigated. The sediment used for the microcosm experiments was aged polluted with NP. The biodegradation of NP in the sediment occurred within 8 days with a lag phase of 2 days at 30°C. During the biodegradation, nitro-nonylphenol metabolites were formed, which were further degraded to unknown compounds. The attached nitro-group originated from the ammonium in the medium. Five subsequent transfers were performed from original sediment and yielded a final stable population. In this NP-degrading culture, the microorganisms possibly involved in the biotransformation of NP to nitro-nonylphenol were related to ammonium-oxidizing bacteria. Besides the degradation of NP via nitro-nonylphenol, bacteria related to phenol-degrading species, which degrade phenol via ring cleavage, are abundantly present.

Phthalates and nonylphenols in urban runoff: Occurrence, distribution and area emission factors

The urban water system is believed to be an important sink for the nonpoint-source pollutants nonylphenols and phthalates. The presence of nonylphenols (NPs), nonylphenol ethoxylates (NPEOs), and eight phthalates was analyzed in urban stormwater and sediment from three catchment areas in Sweden. Emission loads for these substances were then calculated for a specific urban catchment area. In addition, substance distribution in road runoff passing through a sedimentation facility was modeled using a modified QWASI-model for chemical fate. High concentrations of DEHP, DIDP and DINP (<or=48, 66 and 200 microg/g dw, respectively) as well as nonylphenol mono- and di-ethoxylate (6.6 and 20 microg/g dw, respectively) were found in the sediment. Aqueous concentrations of the pollutants varied considerably; branched NP was detected in concentrations up to 1.2 microg/L, whereas di(2-ethylhexyl) phthalate (DEHP), diisodecyl phthalate (DIDP), and diisononyl phthalate (DINP) were the most frequently detected phthalates in concentrations up to 5.0, 17 and 85 microg/L, respectively. The fate modeling demonstrated that predicted substance levels in water agreed well with measured levels, whereas the modeled sediment levels were underestimated. Calculation of catchment area emission factors from an urban highway environment revealed that as much as 2.1 kg of total phthalates and 200 g of NP and NPEOs may be emitted per hectare and year. The results indicate that all monitored phthalates, branched NPs and lower NPEOs are present in Swedish urban water systems. The long-chain phthalates DIDP and DINP are believed to occur at higher concentrations than other phthalates because of their higher environmental persistence and their increasing use in Sweden.

Biodegradation of pharmaceutical and personal care products

Medical treatments and personal hygiene lead to the steady release of pharmaceutical and personal care products (PPCPs) into the environment. Some of these PPCPs have been shown to have detrimental environmental effects and could potentially impact human health. Understanding the biological transformation of PPCPs is essential for accurately determining their ultimate environmental fate, conducting accurate risk assessments, and improving PPCP removal. We summarize the current literature concerning the biological transformation of PPCPs in wastewater treatment plants, the environment, and by pure cultures of bacterial isolates. Although some PPCPs, such as ibuprofen, are readily degraded under most studied conditions, others, such as carbamazepine, tend to be recalcitrant. This variation in the biodegradability of PPCPs can be attributed to structural differences, because PPCPs are classified by application, not chemical structure. The degradation pathways of octylphenol by Sphingomonas sp. strain PWE1, ibuprofen by Sphingomonas sp. strain Ibu-2, and DEET by Pseudomonas putida DTB are discussed in more detail.

Degradation and plant uptake of nonylphenol (NP) and nonylphenol-12-ethoxylate (NP12EO) in four contrasting agricultural soils

Nonylphenol polyethoxylates (NPEOs) are surfactants found ubiquitously in the environment due to widespread industrial and domestic use. Biodegradation of NPEOs produces nonylphenol (NP), an endocrine disruptor. Sewage sludge application introduces NPEOs and NP into soils, potentially leading to accumulation in soils and crops. We examined degradation of NP and nonylphenol-12-ethoxylate (NP12EO) in four soils. NP12EO degraded rapidly (initial half time 0.3-5 days). Concentrations became undetectable within 70-90 days, with a small increase in NP concentrations after 30 days. NP initially degraded quickly (mean half time 11.5 days), but in three soils a recalcitrant fraction of 26-35% remained: the non-degrading fraction may consist of branched isomers, resistant to biodegradation. Uptake of NP by bean plants was also examined. Mean bioconcentration factors for shoots and seeds were 0.71 and 0.58, respectively. Removal of NP from the soil by plant uptake was negligible (0.01-0.02% of initial NP). Root concentrations were substantially higher than shoot and seed concentrations.

Nonylphenol in the environment: a critical review on occurrence, fate, toxicity and treatment in wastewaters

Nonylphenol is a toxic xenobiotic compound classified as an endocrine disrupter capable of interfering with the hormonal system of numerous organisms. It originates principally from the degradation of nonylphenol ethoxylates which are widely used as industrial surfactants. Nonylphenol ethoxylates reach sewage treatment works in substantial quantities where they biodegrade into several by-products including nonylphenol. Due to its physical-chemical characteristics, such as low solubility and high hydrophobicity, nonylphenol accumulates in environmental compartments that are characterised by high organic content, typically sewage sludge and river sediments, where it persists. The occurrence of nonylphenol in the environment is clearly correlated with anthropogenic activities such as wastewater treatment, landfilling and sewage sludge recycling. Nonylphenol is found often in matrices such as sewage sludge, effluents from sewage treatment works, river water and sediments, soil and groundwater. The impacts of nonylphenol in the environment include feminization of aquatic organisms, decrease in male fertility and the survival of juveniles at concentrations as low as 8.2 microg/l. Due to the harmful effects of the degradation products of nonylphenol ethoxylates in the environment, the use and production of such compounds have been banned in EU countries and strictly monitored in many other countries such as Canada and Japan. Although it has been shown that the concentration of nonylphenol in the environment is decreasing, it is still found at concentrations of 4.1 microg/l in river waters and 1 mg/kg in sediments. Nonylphenol has been referred to in the list of priority substances in the Water Frame Directive and in the 3rd draft Working Document on Sludge of the EU. Consequently there is currently a concern within some industries about the possibility of future regulations that may impose the removal of trace contaminants from contaminated effluents. The significance of upgrading sewage treatment works with advanced treatment technologies for removal of trace contaminants is discussed.

Application of the OECD 301F respirometric test for the biodegradability assessment of various potential endocrine disrupting chemicals

The biodegradability of several potential endocrine disrupting compounds, namely 4-n-nonylphenol (4-n-NP), nonylphenol monoethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO), bisphenol A (BPA), triclosan (TCS), di-(2-ethylhexyl)-phthalate (DEHP), perfluorooctanoate (PFOA) and perfluorononanoate (PFNA) was evaluated in this study, using OECD method 301F (manometric respirometry test) and activated sludge as inoculum. According to the results, 4-n-NP and BPA meet the strict definition of ready biodegradability and they are not expected to be persistent during the activated sludge process. Partial biodegradation was observed for DEHP (58.7+/-5.7%, n=3), TCS (52.1+/-8.5%, n=3) and NP1EO (25.9+/-8.1%, n=3), indicating their possible biodegradation in wastewater treatment systems, while no biodegradation was observed for NP2EO, PFOA and PFNA. Experiments in the co-presence of a readily biodegradable compound showed the absence of co-metabolic phenomena during 4-n-NP, BPA and TCS biodegradation. Using first order kinetics to describe biodegradation of the target compounds, half-lives of 4.3+/-0.6, 1.3+/-0.2, 1.8+/-0.5, 6.9+/-2.6 days were calculated for 4-n-NP, BPA, TCS and DEHP, respectively. Toxicity tests using marine bacterium Vibrio fischeri showed that biodegradation of 4-n-NP, NP1EO, BPA and TCS is a simultaneous detoxification process, while possible abiotic or biotic transformations of NP2EO, DEHP, PFOA and PFNA during respirometric test resulted to significant increase of their toxicities.