Effects of micronutrients on biological treatment efficiency of textile wastewater

Micronutrients play a very important role in biological processes for wastewater treatment. Many industrial wastewaters lack in nutrients (macronutrients and micronutrients) required for microbial growth, and this is one of the main problems at many activated sludge plants treating industrial wastewater. The microbial community structure is one of the important factors controlling the pollutant-degrading capacity of biological wastewater treatment system. In this study, the concentrations of micronutrients of the textile wastewater discharged from a textile plant were determined, and the effects of micronutrients on treatment efficiency and microorganism community structure of the biological treatment system were studied. The results showed that the optimal concentrations of magnesium, molybdenum, zinc, thiamine and niacin in the textile wastewater were 5.0, 2.0, 1.0, 1.0 and 1.0mg/L, respectively. The COD removal rates when magnesium, molybdenum, zinc, thiamine and niacin were added individually to the wastewater in their optimal concentrations were 1.8, 1.4, 1.3, 1.6 and 2.2 times of that of the control, respectively. The improving effects of combinations of zinc and thiamine, zinc and niacin, thiamine and niacin were better than single micronutrient. The diversity of quinones (DQ) changed significantly after the micronutrient was added into the wastewater treatment system. This indicated that there was probably a feasibility of optimizing the biological treatment performances and microorganism community structure of textile wastewater treatment system through micronutrient supplement.

The distribution and economic losses of alien species invasion to China

Invasive alien species have become one of the most serious environmental issues in the world. Data of taxon, origin, pathway, and environmental impacts of invasive alien microorganisms, invertebrates, amphibians and reptiles, fish, birds, mammals, herbs, trees, and, marine organisms in terrestrial, aquatic, and marine ecosystems of China were analyzed during 2001 and 2003, based on literature retrieval and field survey. There were 283 invasive alien species in China, and the number of species of invasive alien microorganisms, aquatic plants, terrestrial plants, aquatic invertebrates, terrestrial invertebrates, amphibians and reptiles, fish, and mammals were 19, 18, 170, 25, 33, 3, 10, and 5, respectively. The proportion of invasive alien species originated from America, Europe, Asia, Africa, and Oceania were 55.1, 21.7, 9.9, 8.1, and 0.6%, respectively. Methods for estimation of direct economic losses to agriculture, forestry, stockbreeding, fishery, road and water transportation, storage, water conservancy, environment and public facilities, and human health were established. Methods for estimation of indirect economic losses caused by invasive alien species to service functions of forest ecosystems, agricultural ecosystems, grassland ecosystems, and wetland ecosystems were also established. The total economic losses caused by invasive alien species to China were to the time of USD 14.45 billion, with direct and indirect economic losses accounting for 16.59% and 83.41% of total economic losses, respectively.

The status and causes of alien species invasion in China

Data of classification, origin, pathway and environmental impacts of invasive alien micro-organisms, invertebrates, amphibians and reptiles, fish, birds, mammals, weeds, trees, and marine organisms in terrestrial, aquatic and marine ecosystems of China, were analyzed, based on literature retrieval, field survey and consultation. Some 283 invasive alien species were recorded in China, including 19 invasive alien micro-organisms, 18 aquatic plants, 170 terrestrial plants, 25 aquatic invertebrates, 33 terrestrial invertebrates, 3 amphibians and reptiles, 10 fish, and 5 mammals. Of the invasive alien species, 55.1% originated from North and South America, 21.7% from Europe, 9.9% from Asia, 8.1% from Africa and 0.6% from Oceania. Many institutions and individuals in China lack adequate knowledge of ecological and environmental consequences caused by invasive alien species, with some ignorance of the dangerous invasion in the introduction of alien species. For instance, 50.0% of invasive alien plants were intentionally introduced as pasture, feedingstuff, ornamental plants, textile plants, medicinal plants, vegetables, or lawn plants, 25% of alien invasive animals were intentionally introduced for cultivation, ornament, or biological control, In addition, more efforts are being made in the introduction of alien species, and little attention is paid on the management of introduced alien species, which may cause their escape into natural environment and potential threats to the environment. There were also gaps in quarantine system in China. All microorganisms were unintentionally introduced, through timber, seedling, flowerpot, or soil; 76.3% of alien invasive animals invaded through commodity or transportation facility because of the failure of quarantine. Therefore, quarantine measures should be strictly implemented; and meanwhile the intentional introduction of alien species should be strictly managed and a system of risk assessment should be implemented.

Contributions of phosphatase and microbial activity to internal phosphorus loading and their relation to lake eutrophication

Phosphatase may accelerate the process of lake eutrophication through improving phosphorus bioavailability. This mechanism was studied in three Chinese eutrophic shallow lakes (Lake Taihu, Lake Longyang,and Lake Lianhua). Phosphatase activity was related to the concentration of soluble reactive phosphorus (SRP) and chlorophyll a. Stability of dissolved phosphatase in reverse micelles may be attributed to molecular size, conformation and active residues of the enzyme. At the site with Microcystis bloomed in Lake Taihu, dissolved phosphatase activity was higher and more stable in micelles, SRP concentrations were lower in interstitial water, the contents of different forms of phosphorus and the amounts of aerobic bacteria were lower while respiration efficiency was higher in sediments. Phosphobacteria, both inorganic and organic and other microorganisms were abundant in surface water but rare in sediments. Therefore, internal phosphorus may substantially flux into water column by enzymatic hydrolysis and anaerobic release, together with mobility of bacteria, thereby initiating the bloom. In short, biological mechanism may act in concert with physical and chemical factors to drive the internal phosphorus release and accelerate lake eutrophication.

Biodegradation of dibenzofuran by Janibacter terrae strain XJ-1

The dibenzofuran (DF)-degrading bacterium, Janibacter terrae strain XJ-1, was isolated from sediment from East Lake in Wuhan, China. This strain grows aerobically on DF as the sole source of carbon and energy; it has a doubling time of 12 hours at 30 degrees C; and it almost completely degraded 100 mg/L-1 DF in 5 days, producing 2,2',3-trihydroxybiphenyl, salicylic acid, gentisic acid, and other metabolites. The dbdA (DF dioxygenase) gene cluster in the strain is almost identical to that on a large plasmid in Terrabacter sp. YK3. Unlike Janibacter sp. strain YY-1, XJ-1 accumulates gentisic acid rather than catechol as a final product of DF degradation.

NK-lysin of channel catfish: Gene triplication, sequence variation, and expression analysis

Antimicrobial peptides (AMPs) are important components of the host innate immune response against microbial invasion. In addition to the previously known four classes of antimicrobial peptides, a fifth class of antimicrobial peptides has been recently identified to include NK-lysins that have a globular three-dimensional structure and are larger with 74-78 amino acid residues. NK-lysin has been shown to harbor antimicrobial activities against a wide spectrum of microorganisms including bacteria, fungi, protozoa, and parasites. To date, NK-lysin genes have been reported from only a limited number of organisms. We previously identified a NK-lysin cDNA in channel catfish. Here we report the identification of two noveltypes of NK-lysin transcripts in channel catfish. Altogether, three distinct NK-lysin transcripts exist in channel catfish. In this work, their encoding genes were identified, sequenced, and characterized. We provide strong evidence that the catfish NK-lysin gene is tripled in the same genomic neighborhood. All three catfish NK-lysin genes are present in the same genomic region and are tightly linked on the same chromosome, as the same BAC clones harbor all three copies of the NK-lysin genes. All three NK-lysin genes are expressed, but exhibit distinct expression profiles in various tissues. In spite of the existence of a single copy of NK-lysin gene in the human genome, and only a single hit from the pufferfish,genome, there are two tripled clusters of NK-lysin genes on chromosome 17 of zebrafish in addition to one more copy on its chromosome 5. The similarity in the genomic arrangement of the tripled NK-lysin genes in channel catfish and zebrafish suggest similar evolution of NK-lysin genes. (c) 2005 Elsevier Ltd. All rights reserved.

Application of polyurethane foam units and calorimetry to microbial monitoring in Lake Donghu

Combined with the national standard biomonitoring method (polyurethane foam units method), calorimetry was applied to study the metabolic activities of PFU microbial communities in fresh water to determine the effects of anthropotgenic stresses on the activity of the microbial community. Comparisons were made at four sampling stations with different eutrophic status in Lake Donghu. Water quality variables, species number of protozoa, abundances of microorganisms, biomass, heterotrophy indexes and diversity indexes are reported. The heat rate-time curves of the native and concentrated PFU microbial communities were determined at 28 degrees C. Growth rate, measured maximum power output and total heat were calculated from the heat rate-time curves. The values of metabolic variables are higher at the more eutrophic stations, which suggests that organic pollution increases the activity of PFU microbial communities. The metabolic variables are in good agreement with chemical and biotic variables. And calorimetry will be useful for biomonitoring of the PFU microbial community. (C) 2005 Elsevier B.V. All rights reserved.

Photoregulated or energy dependent process of hormogonia differentiation in Nostoc sphaeroides Kutzing (Cyanobacterium)

Hormogonium, which was thought to play an important role in the dispersal and survival of these microorganisms in their natural habitats, is a distinguishable developmental stage of heterocystous cyanobacteria. The present study examined the effects of different light conditions and sugars on the differentiation of Nostoc sphaeroides Kutzing to the hormogonia stage. Results showed that differentiation of hormogonia was light dependent in the absence of sugar, but that close to 100% of cyanobacteria differentiated to hormogonia in the presence of glucose or sucrose, irrespective of the light conditions. This differentiation was inhibited, even in the presence of sugars, upon application of an inhibitor of respiration. Following the testing of different sugars, the effects of different lights were examined. It was found that 5 10 μ mol.m(-2)• s(-1) photon flux density was optimal for hormogonia differentiation. One hundred percent differentiation was obtained with white light irradiation, in contrast with irradiation with green light (80% differentiation) and red light (0-10% differentiation). Although they showed different efficiencies in inducing hormogonia differentiation in N. sphaeroides, the green and red radiation did not display antagonistic effects. When the additional aspect of time dependence was investigated through the application of different light radiations and an inhibitor of protein synthesis, it was found that the initial 6 h of the differentiation process was crucial for hormogonia differentiation. Taken together, these results show that hormogonia differentiation in N. sphaeroides is either a photoregulated or an energy dependent process.

Cultured gill epithelial cells from tilapia (Oreochromis niloticus): a new in vitro assay for toxicants

A culture gill epithelium from seawater-adapted tilapia (Oreochromis niloticus) was developed for testing PAHs and dioxin-like contaminants in seawater. The epithelia consists two to three layers of epithelial cells incorporating both pavement cells and mitochondria-rich cells (MRCs). Polarity and a stable transepithelial resistance (TER) were maintained. and closely resembled those in fish gills in vivo. The tightness (integrity) of the epithelia remained unchanged upon exposure to benzo[a]pyrene (B[a]P). 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 3,3',4,4',5-pentachlorobiphenyl (PCB#126), while a concentration-dependent response of EROD activity in the epithelia was induced within 18-24 h when the apical side was exposed to these toxicants. The 24 h EC50 of EROD activity was 2.77 x 10(-7) M for PCB#126, 1.85 x 10(-7) M for B[a]P and 7.38 x 10(-10) M for TCDD. showing: that the preparation was not only sensitive to PAHs and dioxin-like compounds, but also able to produce inductive potency of AhR agonists that generally agreed with those derived from other established in vitro and in vivo systems. The results suggest, that the cultured gill epithelia from seawater-adapted tilapia may serve as a simple. rapid and cost-effective tool for assessing exposure and potential effects of toxicants in marine waters. (C) 2004 Elsevier B.V. All rights reserved.

Differing estrogen activities in the organic phase of air particulate matter collected during sunny and foggy weather in a Chinese city detected by a recombinant yeast bioassay

Total air suspended particles (PM 100) collected from an urban location near a traffic line in Wuhan, China, were examined for estrogen using a recombinant yeast bioassay. Wuhan, located at the central part of China, is the fourth biggest city in China with 7 million populations. Today, Wuhan has developed into the biggest city and the largest traveling center of central China, becoming one of the important bases of industry, education and research. Wuhan is right at the confluent point of Yangzi River, the third longest river in the world, and its largest distributary Hanjiang, with mountains and more than 100 takes in downtown area. Therefore, by its unique landscape, Wuhan has formed clear four seasons with relatively long winter and summer and short spring and autumn. Foggy weather usually happen in early spring. The yeast line used in this assay stably expresses human estrogen receptor-alpha. Weak but clear estrogenic activities were detected in the organic phase of crude extracts of air particle materials (APM) in both sunny and foggy weather by 0.19-0.79 mug E2/gPM(100) which were statistically significantly elevated relative to the blank control responding from 20% to 50% of the maximum E2 response, and the estrogenic activity was much higher in foggy weather than in sunny weather. The estrogenic activities in the sub-fractions from chromatographic separation of APM sampled in foggy days were also determined. The results indicated that the responses of the fractions were obviously higher than the crude extracts. Since there is no other large pollution source nearby, the estrogenic material was most likely from vehicle emissions, house heating sources and oil fumes of house cooking. The GC/MS analysis of the PM100 collected under foggy weather showed that there were many phenol derivatives, oxy-PAHs and resin acids which have been reported as environmental estrogens. These results of the analysis of estrogenic potency in sunny and foggy weather in a subtropical city of China indicate that further studies are required to investigate the actual risks for the associated health and atmospheric system. (C) 2004 Elsevier Ltd. All rights reserved.

Root zone microbial populations, urease activities, and purification efficiency for a constructed wetland

In order to investigate the effects of microorganisms and their urease activities in macrophytic root zones on pollutant removal, four small-scale plots (SSPs) of vertical/reverse-vertical flow wetlands were set up to determine: a) the relationship between the abundance of microorganisms in the root zones and water purification efficiency; and b) the relationship between urease activities in the root zones and pollutant removal in a constructed wetland system. Total numbers of the microbial population (bacteria, fungi, and actinomyces) along with urease activities in the macrophytic root zones were determined. In addition, the relationships between microbial populations and urease activities as well as the wastewater purification efficiencies of total phosphorus (TP), total Kjeldahl nitrogen (TKN), biochemical oxygen demand in 5 days (BOD5), and chemical oxygen demand (COD) were also analyzed. The results showed that there was a highly significant positive correlation (r = 0.9772, P < 0.01) between the number of bacteria in the root zones and BOD5 removal efficiency and a significant negative correlation (r = -0.9092, P < 0.05) between the number of fungi and the removal efficiency of TKN. Meanwhile, there was a significant positive correlation (r = 0.8830, P < 0.05) between urease activities in the root zones and the removal efficiency of TKN. Thus, during wastewater treatment in a constructed wetland system, microorganism and urease activities in the root zones were very important factors.

Presence of estrogenic activity from emission of fossil fuel combustion as detected by a recombinant yeast bioassay

Estrogenic activities of emission samples generated by fossil fuel combustion were investigated with human estrogen receptor (ER) recombinant yeast bioassay. The results showed that there were weak but clear estrogenic activities in combustion emissions of fossil fuels including coal, petroleum, and diesel. The estrogenic relative potency (RP) of fossil fuel combustion was the highest in petroleum-fired car, followed by coal-fired stove, diesel-fired agrimotor, coal-fired electric power station. On the other hand, the estrogenic relative inductive efficiency (RIE) was the highest in coal-fired stove and coal-fired electric power station, followed by petroleum-fired car and diesel-fired agrimotor. The estrogenic activities in the sub-fractions from chromatographic separation of emitted materials were also determined. The results indicated that different chemical fractions in these complex systems have different estrogenic potencies. The GC/MS analysis of the emission showed that there were many aromatic carbonyls, big molecular alcohol, PAHs and derivatives, and substituted phenolic compounds and derivatives which have been reported as environmental estrogens. The existence of estrogenic substances in fossil fuel combustion demands further investigation of their potential adverse effects on human and on the ecosystem. The magnitude of pollution due to global usage of fossil fuels makes it imperative to understand the issue of fossil fuel-derived endocrine activities and the associated health risks, particularly the aggregated risks stemmed from exposure to toxicants of multiple sources. (C) 2003 Elsevier Science Ltd. All rights reserved.

Estrogenic effects from household stoves

With the application of a genetically modified yeast, estrogen receptor-activating compounds were detected in the soot and emission gas of a wood-burning household stove. The EC50 value of 17beta-estradiol was divided by the EC50 value of soot, and the obtained relative estrogenic value for raw soot was 2.37E-5, indicating that soot was about 100,000 times less estrogenic than 17beta-estradiol. Chemical analysis revealed that alkyl phenol, benzonic acid, and PAHs represented the major constituents in the most potent fractions of the soot. Along with PAHs, other constituents might also contribute to the estrogenicity of soot. (C) 2002 Elsevier Science (USA).

Optimization of control parameters for petroleum waste composting

Composting is being widely employed in the treatment of petroleum waste. The purpose of this study was to find the optimum control parameters for petroleum waste in-vessel composting. Various physical and chemical parameters were monitored to evaluate their influence on the microbial communities present in composting. The CO2 evolution and the number of microorganisms were measured as the activity of composting. The results demonstrated that the optimum temperature, pH and moisture content were 56.5 - 59.5 degreesC, 7.0 - 8.5 and 55 % - 60%, respectively. Under the optimum conditions, the removal efficiency of petroleum hydrocarbon reached 83.29% after 30 days composting.

Relationship between tissue concentrations of polycyclic aromatic hydrocarbons and DNA adducts in green-lipped mussels (Perna viridis)

Green-lipped mussels (Perna viridis) were collected from a site in Hong Kong which is relatively free from polycyclic aromatic hydrocarbon (PAH) contamination, and maintained in situ at this and three other sites with different degrees of PAH contamination. The transplanted mussels were retrieved after a 30-day field exposure. DNA adducts in the gill tissues were quantified, and tissue concentrations of benzo[a]pyrene as well as total PAHs (with potential carcinogenicity) determined for individual mussels. Results indicate that (1) tissue concentration of PAHs and adduct levels in mussels collected from a single site can be highly variable; and (2) adduct levels were related to tissue concentrations of benzo[a]pyrene as well as total PAHs of individual animals.