Risk assessment of polycyclic aromatic hydrocarbons in aquatic ecosystems.

A probability risk assessment of anthracene, benzo(a)pyrene, chrysene, fluorene, phenanthrene and pyrene was carried out to examine the ecological risk of these six polycyclic aromatic hydrocarbons (PAHs) in aquatic ecosystems in China. The literature on PAH concentrations in surface water in China was collected to evaluate the environmental exposure concentrations (EEC). The 10th percentile of predicted no observed effect concentration (PNEC(10%)) of PAHs, calculated according to the data from the USEPA AQUIRE database and regulatory reviews, was applied as the toxicity assessment endpoint. The ratio of EEC and PNEC(10%), expressed as a risk quotient (RQ), was used to characterize the risk value. Bootstrapping method and Monte Carlo simulation were utilized to calculate the distribution of EEC, PNEC(10%), RQ and associated uncertainties. Risk assessment showed that reliable maximum RQs of anthracene, benzo(a)pyrene, chrysene, fluorene and phenanthrene were in the range of 0.064-0.755, lower than the acceptable value of 1. However, the reliable maximum RQ of pyrene was 1.39, indicating its potential ecological risk. Notwithstanding the uncertainty, these results suggest that the aquatic ecosystems with high PAH concentrations might pose potential ecological risks, and concerted efforts are required to ensure that surface water is protected.

Comparative analysis of binding affinities between styrene and mammalian CYP2E1 by bioinformatics approaches.

Cytochrome P450 2E1 (CYP2E1) is a cytochrome P450 enzyme involved in styrene metabolism. This study compared the binding affinities between styrene and 11 mammalian CYP2E1 systems using bioinformatics methods. Firstly, amino acid sequences of CYP2E1s were obtained from the Swiss-Prot database. Then, taking the crystal structure of human CYP2E1 as a template, 3D models of the CYP2E1s of other mammals were constructed using the SWISS-MODEL program. Finally, the generated homology models were applied to calculate their docking capacities against styrene and polystyrene using the Surflex-Dock program, which could automatically dock ligands into a receptor's ligand binding site using a protomol based approach and assess the affinity by an empirically derived scoring function. Docking experiments showed that the studied mammalian CYP2E1s had high binding affinities with styrene. For polystyrene, the dimmer of styrene has high binding affinities with CYP2E1s, however, trimer and other high polymers were found hard to be docked into the CYP2E1s. The results of this study indicated that bioinformatics approaches might be useful tools to predict styrene and polystyrene affinities with mammalian CYP2E1s.

Serum biochemical analysis to indicate pathogenic risk on mouse Mus musculus exposure to source of drinking water.

The 18 biochemical parameters of serum were measured to analyze the pathogenic risks of the Yangtze River Source of Drinking Water in Nanjing area (YZR-SDW-NJ) on mouse Mus musculus for protection of human health in this research. The male mice Mus musculus were sampled and fed with YZR-SDW-NJ for 90 days then the eighteen serum biochemical levels were measured with Automatic Biochemical Analysis/RerLi 600. And the parameter data were treated by One-Way ANOVA statistic approach. The results showed that five parameter levels for the sample group mice were different from those for the control group significantly (0.01 < P or 0.05 < P). Four 4 of the 5 altered parameter levels were decreased including glutamate pyruvate transaminase 38% lower, glutamine-oxaloacetic transaminase 24% lower, triglyceride 76% lower and cystatin C 73% lower, only creatinine level was 26% higher than that in the control group. The data suggest that YZR-SDW-NJ had toxicity on the mouse and the organic pollutants in YZR-SDW-NJ might lead to liver, kidney, cardiovascular and metabolic pathogenic risks on the human beings. The results might be cited as evidence to control pollutants in the source water for the protection of NJ people's health.

Characterization and quantification of class 1 integrons and associated gene cassettes in sewage treatment plants.

Class 1 integrons and gene cassettes containing antibiotic resistance genes (ARGs) in five different sewage treatment plants (STPs) were characterized and quantified using polymerase chain reaction (PCR), sequencing, and quantitative real-time PCR (qRT-PCR) in this study. Class 1 integronase gene (intI1) was found commonly occurring in all of activated sludge samples from the five STPs, as well as in influent and effluent of two STPs at Hong Kong. One hundred and nine lactose-fermenting Enterobacteriaceae (LFE) strains were isolated from activated sludge of Shatin STP. Among them, 36 strains (33.0%) were found to carry class 1 integrons. PCR assays showed that 11 of the 36 intI1-carrying isolates harbored a common type of gene cassette array of about 1,600 bps, as well as the static genes (sulI and qacEDelta1) on class 1 integrons. This gene cassette array was found phylogenetically close to antibiotic resistance genes dfr17 and aadA5, encoding dihydrofolate reductase conferring resistance to trimethoprim and adenylyltransferase conferring resistance to spectinomycin/streptomycin, respectively. Antimicrobial susceptibility analysis demonstrated that all the 11 LFEs carrying gene cassette were multi-resistant, especially having common resistance to trimethoprim and streptomycin. qRT-PCR assay showed that genes copies of both class 1 integron and the gene cassette varied significantly among the activated sludge sampled from different STPs, at different time points or different treatment steps. More than 90% of class 1 integrons and the gene cassette were removed by activated sludge processes in two STPs, while the disinfection process removed 94% integron and 77% gene cassette in one STP.

PTA wastewater molecular toxicity detected with gene chip.

The purified terephthalic acid (PTA) petrochemical wastewater molecular toxicity detected by use of Mouse Genome 430A 2.0 GeneChip was conducted in this research. The toxic dose to male mice was 0.03 g/(kg x d) of PTA in the wastewater. The mice liver total RNA was isolated as the temple for synthesis of cDNA and then the cDNA as the temple for synthesis of cRNA. Hybridizing the cRNA with the target genes on the gene chip, there were 232 genes expression levels up-regulated and 74 genes down-regulated discovered obviously. The foremost 40 genes for both the highest and the lowest expression levels involved endogenetic steroid and hormone metabolism, immune system, the leukocyte activity and inflammation, detoxification in liver, reproduction and growth hormone, regulation immune factors of anti-tumor and anti-infection and cancer to the mice sampled. The data suggest the PTA wastewater contained over 5 aromatics and their toxicities integrated were much higher than the pure chemical PTA. And the pure chemical PTA toxicities data cannot be used to evaluate the toxicity of the PTA wastewater instead.

Purified terephthalic acid wastewater biodegradation and toxicity.

The biodegradation and toxicity of the purified terephthalic acid (PTA) processing wastewater was researched at NJYZ pilot with the fusant strain Fhhh in the carrier activated sludge process (CASP). Sludge loading rate (SLR) for Fhhh to COD of the wastewater was 1.09 d(-1) and to PTA in the wastewater was 0.29 d(-1). The results of bioassay at the pilot and calculation with software Ebis3 showed that the 48h-LC50 (median lethal concentration) to Daphnia magna for the PTA concentration in the wastewater was only 1/10 of that for the chemical PTA. There were 5 kinds of benzoate pollutants and their toxicities existing in the wastewater at least. The toxicity parameter value of the pure chemical PTA cannot be used to predicate the PTA wastewater toxicity. The toxicity of the NJYZ PTA wastewater will be discussed in detail in this paper.

Pilot regulation of MnP-SA for treating PTA wastewater.

In the pilot study of treating the purified terephthalic acid (PTA) wastewater with the functional Strain Fhhh in the carrier activated sludge process (CASP), the ratio of COD: TN: TP and the concentrations of Cu, Mn, Se and Zn were controlled to improve the manganese peroxidase (MnP) levels for increasing the treatment efficiency. When the ratio of COD: TN: TP was 100: 0.36: 0.15 and the concentrations of Cu, Mn, Se and Zn were 0.54, 5.07, 0.00 and 0.08 mg/L, the MnP specific activity (MnP-SA) reached 689 U/L, and the sludge loading rate to COD(SLRC) was 1.09 d(-l), which was 4--7 fold of that in other processes reported. The data indicated that improving MnP level could enhance the degradability of Fhhh. And the potentials of Fhhh and CASP will be also discussed in this paper.

Predication of Fhhh potential in PTA wastewater treatment.

Ebis is the intelligent environmental biotechnological informatics software developed for judging the effectiveness of the microorganism strain in the industrial wastewater treatment system(IWTS) at the optimal status. The parameter, as the objective function for the judgment, is the minimum reactor volume(Vmin) calculated by Ebis for microorganism required in wastewater treatment. The rationality and the universality of Ebis were demonstrated in the domestic sewage treatment system(DSTS) with the data published in USA and China at first,then Fhhh strain's potential for treating the purified terephthalic acid(PTA) was proved. It suggests that Ebis would be useful and universal for predicating the technique effectiveness in both DSTS and IWTS.

Analysis of parental strain DNA fragments existing in GEMs-Fhhh.

There were 6 target DNA fragments of the three parental strains existing in the cell of GEMs (genetically engineered microorganism strain) Fhhh measured in this research by PCR(polymerase chain reaction). The determination showed that GEMs Fhhh contained all the 6 target DNA fragments, mnp1, mnp2, lip1, lip2, FLO1 and 16S rDNA, and had the molecular genetic stability. Meanwhile the PCR production of each parental strain could only had its target DNA fragments and was different from each other. It may illustrate that the technique of the inter-kingdom protoplast fusion for the construction of GEMs Fhhh through the process of intercellular gene recombination could be used as a reliable bioengineering technique to create the specific functional stain for the pollution control.

A metabonomic analysis on health effects of drinking water on male mice (Mus musculus).

Health effects of drinking water on the male mice (Mus musculus) were investigated by metabonomics after exposure to the Taihu drinking water for 90 days. Metabonomics data combined with the results of conventional serum biochemistry tests and hepatic histopathology showed that the drinking water induced adverse health effects on the male mice. It was found that the serum levels of pyruvate, glutamine, arginine, lysine, N-acetyl glycoproteins, choline and citrate were significantly decreased in the treatment group. These results indicated that Taihu drinking water may induce damages on mice liver via perturbations of energy metabolism, amino acid metabolism and apoptosis. These observations yielded novel insights regarding the environmental health risk of Taihu drinking water.

Health risk assessment of polycyclic aromatic hydrocarbons in the source water and drinking water of China: Quantitative analysis based on published monitoring data.

A carcinogenic risk assessment of polycyclic aromatic hydrocarbons (PAHs) in source water and drinking water of China was conducted using probabilistic techniques from a national perspective. The published monitoring data of PAHs were gathered and converted into BaP equivalent (BaP(eq)) concentrations. Based on the transformed data, comprehensive risk assessment was performed by considering different age groups and exposure pathways. Monte Carlo simulation and sensitivity analysis were applied to quantify uncertainties of risk estimation. The risk analysis indicated that, the risk values for children and teens were lower than the accepted value (1.00E-05), indicating no significant carcinogenic risk. The probability of risk values above 1.00E-05 was 5.8% and 6.7% for adults and lifetime groups, respectively. Overall, carcinogenic risks of PAHs in source water and drinking water of China were mostly accepted. However, specific regions, such as Yellow river of Lanzhou reach and Qiantang river should be paid more attention. Notwithstanding the uncertainties inherent in the risk assessment, this study is the first attempt to provide information on carcinogenic risk of PAHs in source water and drinking water of China, and might be useful for potential strategies of carcinogenic risk management and reduction.

Computational studies of interactions between endocrine disrupting chemicals and androgen receptor of different vertebrate species.

Homology modeling and molecular docking were used to in silico analyze the interactions between six endocrine disrupting chemicals (EDCs) and 11 androgen receptors (ARs) of different vertebrate species. The MODELLER 9V7 program was employed to construct the homology models of AR ligand binding domains (LBDs) from birds, amphibians, bony fishes and cartilaginous fishes. The Surflex-Dock program was applied to calculate and analyze the binding affinities between the six EDCs and AR LBDs. The docking experiment showed that AR LBDs had high affinities with nonyl phenol (NP) and butyl benzyl phthalate (BBP), but low affinities with the 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE153). The results of cluster analysis suggested that predicted binding affinities were species-specific, which was consistent with the phylogenetic analysis of AR LBDs. The difference of binding affinities could be mainly due to the different hydrogen bonds and the orientation of ligands in the binding pockets. Our results suggest that integrated methods of phylogenetic analysis, homology modeling and molecular docking might be a potential tool to predict the different interactions between contaminants and associated receptors in different trophic levels.

Influences of hydraulic loading rate on SVOC removal and microbial community structure in drinking water treatment biofilters.

Six biofilters were used for advanced treatment of Yangtze River source water to investigate the effects of hydraulic loading rate (HLR) on pollutant removal and microbial community. HLR was found to exert significant influences on the removal efficiency of the conventional pollutants and 24 detectable semivolatile organic compounds (SVOCs). More than 85% of chemical oxygen demand and assimilable organic carbon was removed at the optimal HLR of 3.0 m h(-1). With the increase of HLR, SVOC removal showed a decreasing trend. Di-n-butyl phthalate and bis(2-ethylhexyl)phthalate, two main SVOCs in the source water, had the highest removals of 71.2% and 84.4%, respectively. Nearly 65% of 2,6-dinitrotoluene and 80% of isophorone were removed at the lowest HLR. Phylogenetic analysis showed that Escherichia coli, Shigella sp., E. fergusonii and Firmicutes bacteria predominated in the bioreactors. The dominance of E. coli in the low-HLR biofilters might contribute greatly to the high SVOC removal.

Toxicity of purified terephthalic acid manufacturing wastewater on reproductive system of male mice (Mus musculus).

Reproductive toxicity of purified terephthalic acid (PTA) manufacturing wastewater on the male mice (Mus musculus) was investigated after 35-day intragastric perfusion treatment with the wastewater. Fluorescein diacetate and propidium iodide staining, and flow cytometry were used to assess the toxicity of PTA wastewater on spermatogenic cells. PTA wastewater induced significant variations in the relative percentages of immature haploid, diploid, tetraploid and S-phase spermatogonia. Percentage of viable spermatogenic cells was reduced from 93.1+/-2.3 in control group to 90.4+/-1.9 in the wastewater-treated group. Testicular histopathology revealed expansion of interstitial space and reduction in the number and size of Leydig cells induced by the wastewater, which was further certified by the decrease (10.6%) in relative testes weight and the increase (101.3%) in sperm shape abnormality in the wastewater-treated group. In this study, PTA wastewater was found to have reproductive toxicity on male mice, and public health problems may potentially arise from the discharge of the wastewater into the environment.

Genetic analysis of protoplast fusant Xhhh constructed for pharmaceutical wastewater treatment.

In order to analyse genetic relationships between functional strain Xhhh previously constructed through protoplast fusion for pharmaceutical wastewater treatment and its parents, random amplification polymorphic DNA (RAPD) and polymerase chain reaction (PCR) were used to investigate genetic similarities among the strains based on genome and functional genes analyses. A total of 739 clear and consistent bands were produced in the RAPD fingerprint analysis with 40 primers. The genetic similarity indices between Xhhh and parental strains PC (Phanerochaete chrysosporium), SC (Saccharomyces cerevisiae) and XZ (native bacterium Bacillus sp.) were 36.21%, 37.73% and 37.48%, respectively. With PCR amplification and DNA sequencing, Xhhh was found containing functional genes of mnp and lip from PC, FLO1 from SC and 16S rDNA fragments from XZ. Experimental results of genetic analyses were in accordance with Xhhh biochemical and phenotypic characteristics, and protoplast fusion technique is considered as a promising technique in environmental pollution control.

[Toxicity evaluation of purified terephthalic acid wastewater by using model Caenorhabditis elegans].

By using model Caenorhabditis elegans, the toxicity of purified terephthalic acid (PTA) wastewater was evaluated through a battery of biotest, including life span, days of 50% lethal, generation time, brood size, head thrashes, and body bends. The results revealed that compared with control, the life span and generation time of C. elegans exposed to 660 mg PTA x L(-1) were delayed to some degree, and its head thrashes and body bends were inhibited. The procreation function of C. elegans exposed to PTA wastewater was greatly affected, with the brood size being as low as 25% of the normal one. The most sensitive indicator, brood size of C. elegans, might be a potential indicator in evaluating PTA wastewater toxicity.

[Effectiveness for medicine wastewater treatment biotechnology].

The effectiveness for the XZEH medicine wastewater treatment biotechnology was conducted. The results show that it needs to increase 28% of the aeration tank volume in order to meet the effluent COD concentration at the first grade wastewater discharge standard level in China. If the engineered strain Xhhh and informatics software (Ebis) were used, the specific degradation rate of Xhhh strain may be higher 128% than that of the natural bacterium XZ strain and the aeration tank needed may be 51% decreased. This should be a potential technical patch for improving the biotechnological effectiveness and making the effluent at the first grade discharge standard.