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The pretreatment of wheat straw has been recognized to be an essential step prior to anaerobic digestion, owing to the high abundance of lignocellulosic materials. In order to choose economical and effective techniques for the disposal of wheat straw, effects of five pretreatment methods including acid, alkali, co-pretreatment of acid and alkali, CaO2, and liquid digestate of municipal sewage sludge on anaerobic digestion of wheat straw were investigated by analyzing biogas production and organic matter degradation in the study. The results showed that among these pretreatment methods, the methane yield was highest in the liquid digestate pretreated-wheat straw with 112.6 mL gTS−1, followed by the acid, alkali, and CaO2 pretreatments, and the lowest was observed in the co-pretreatment of acid and alkali. Illumina MiSeq sequencing of the microbial communities in the anaerobic digesters revealed that the genera Ruminiclostridium including Ruminiclostridium and Ruminiclostridium 1, Hydrogenispora, and Capriciproducens were the main hydrolytic bacteria, acidogenic bacteria, and acetogenic bacteria, respectively, in the anaerobic digesters. Capriciproducens and Hydrogenispora dominated in the first and the later stages, respectively, in the anaerobic digesters, which could work as indicators of the anaerobic co-digestion stage of sludge and wheat straw. The total solid and SO42−-S contents of the solid digestate and the NH4+-N concentration of the liquid digestate had a significant influence on the microbial community in the digesters. These findings indicated that liquid digestate pretreatment was a potential option to improve the anaerobic digestion of wheat straw, due to the low cost without additional chemical agents.

In order to realize the value-added utilization of food waste (FW), the preparation of crayfish (Procambarus clarkii) feed by yeast fermentation was investigated. Firstly, the suitable fermentation condition was obtained through a single factor experiment as follows: the initial moisture of the FW was adjusted to 60% with bran and inoculated with a 2% yeast mixture (Saccharomyces cerevisiae, Candida utilis, and Yarrowia lipolytica, 3:2:1) followed by aerobic solid-state fermentation for 7 days. The crude protein and acid-soluble protein contents in the fermented feed were 25.14% and 5.16%, which were increased by 8% and 140.67%, respectively. The crude fat content was 0.74%, decreased by 68.29%. The content of antioxidant glutathione (571.78 μg/g) increased 63.33%, and the activities of protease and amylase increased nearly 9 and 3 times, respectively. The maximum degradation rates of aflatoxin B1, zearalenone, and deoxynivalenol were 63.83%, 77.52%, and 80.16%, respectively. The fermented feeds were evaluated by substituting (0%, 10%, 30%, 50%, and 100%) commercial diet for crayfish (30-day culture period). When the replacement proportion was 30%, the weight gain of crayfish reached 44.87% (initial body weight 13.98 ± 0.41 g), which was significantly increased by 10.25% compared with the control (p = 0.0005). In addition, the lysozyme and SOD enzyme activities in crayfish hepatopancreas were also increased significantly. Our findings suggest that yeast-fermented feed from FW can replace 30% of crayfish's conventional diet, which may improve crayfish's antioxidant capacity and enhance non-specific immunity by providing molecules such as glutathione.

Algae decay is an important process influencing environmental variables and emissions of volatile sulfur compounds (VSCs) in eutrophic lakes. However, effects of algae decay on VSC emissions from eutrophic lakes as well as fate of algae-derived sulfur remain poorly understood. In this study, simulated algae-sediment systems were used to explore the flow and distribution of sulfur during algae decay. VSCs including hydrogen sulfide (H

Excessive application of phosphorus (P) fertilizer to the agriculture soil can lead to the P loss to the aquatic ecosystem. Three soils from different land use (tea, paddy, and vegetable soils) were treated with biogas slurry (BS) at rate of 79.8 kg ha−1, anionic polyacrylamide (PAM) at rate of 12.5, 25 and 50 kg ha−1, Gypsum (Gy) at rate of 5t ha−1, and the control (Ck) without treatment, to control P losses in a laboratory batch experiment. The soil solution was analyzed for total P (TP), dissolved reactive P (DRP) and total dissolved P (TDP). Particulate P (PP) and dissolved unreactive P (DURP) were calculated by subtracting DRP from TP and TDP, respectively. The DRP was within a range of 68–98% of TP whereas PP varied in a range of 2–32% of TP and DURP was within a range of 0.1–19% of TP, depending on soil types and different treatments. The addition of PAM at a high rate and Gy together on the soil after BS application reduced the release of TP by 54, 46, and 51% and that of DRP by 61, 49, and 53% for tea, paddy and vegetable soils, respectively. However, the application of BS with PAM alone promoted the release of DRP by 77, 86, 70% for tea, paddy, and vegetable soils, respectively. This study suggests that the synergic application of PAM and Gy on soils after BS addition can be a good strategy to reduce P losses.

Laboratory incubation experiments using 15N stable isotope labeling and acetylene suppression techniques were conducted to compare the autotrophic nitrification and heterotrophic nitrification rates with the addition of swine manure (SW) and swine-manure-derived biochar (SWB) in two paddy soils. SW and SWB were applied at four N-based amendment levels, namely control (0 mg N kg−1), low (1.1 mg N kg−1), medium (2.2 mg N kg−1), and high (4.4 mg N kg−1). Twenty-five milliliters of C2H2 gas were injected into each storage bottle to inhibit autotrophic nitrification in soil. At the end of the preincubation period, 160 mg kg−1 15N-glycine were added to each storage bottle to stimulate heterotrophic nitrification in soil. Results showed that SW increased the NH4+-N content by 3.5 to 17.5 mg kg−1 in both soils, while SWB decreased it by 0.1 to 4.7 mg kg−1 compared to control group, regardless of whether autotrophic nitrification was inhibited. Both SW and SWB enhanced NO3−-N accumulation in the two soils compared to control group when autotrophic nitrification was not inhibited; however, NO3−-N concentration in the soil with SWB was up to 24% lower than that with the same level of SW addition. NH3 volatilization rates were elevated at all the SW and SWB amendment levels, although only SW led to higher N2O emission rates. Compared with SW, high level of SWB significantly decreased N2O emissions by 78 to 84% in the loam and clay loam soils. The increase in NH3 volatilization, soil NO3−-N accumulation, and autotrophic nitrification rate were greater with SW than with SWB. Higher rates of soil heterotrophic nitrification were observed in SWB-amended soils than in SW-amended soils with a high (4.4 mg N kg−1) amendment level. Our results suggest that SWB is less likely to increase NO3−-N accumulation in soil and contributes more to the lower soil autotrophic nitrification rate compared with SW. Although SWB can promote heterotrophic nitrification, it generally inhibits the autotrophic nitrification process and slows the increment pace of the gross nitrification in paddy soils.

The inhibitory effects of oxytetracycline (OTC) on the anaerobic ammonium oxidation (anammox) performance were relieved by employing bio-augmentation (BA) tactics. However, the recovery mechanism was vague. The response of specific anammox activity (SAA), heme c, functional genes, extracellular polymeric substance (EPS) and antibiotics resistance genes (ARGs) to OTC inhibition and BA aid were traced in the present study. The results indicated that response of SAA, heme c content and functional genes, such as nirS, hzsA and hdh to OTC inhibition were not synchronous. The presence of the tetC, tetG, tetX, and intI1 genes enhanced the resistance of anammox sludge to OTC, thus accelerating the performance recovery when aided by BA. A significant correlation existed between number of anammox 16S rRNA gene copies and protein level in the soluble microbial products (SMP), between tetG gene relative abundance and polysaccharose in SMP and between tetG gene relative abundance and protein in bound EPS (EPSs). In nutshell, the current findings provide the first description of a recovery mechanism regarding OTC-inhibited anammox performance aided by BA based on functional genes and highlights the contribution of ARGs and the self-resistance ability of EPS.

Myxovirus resistance (Mx) proteins are interferon (IFN)-inducible Dynamin-like GTPases, which play an important role in antiviral immunity. Three Mx genes (Mx1-3) have been cloned previously in rainbow trout. In this study, an additional six Mx genes were cloned that reside in four chromosomal loci. Further bioinformatics analysis suggests the presence of three teleost Mx groups (TMG) each with a characteristic gene organisation. Salmonid Mx belong to TMG1 and TMG2. The increased salmonid Mx gene copies are due mainly to local gene duplications that happened before and after salmonid speciation, in a lineage/species specific manner. Trout Mx molecules have been diversified in the loop 1 and 4 regions, and in the nuclear localisation signal in loop 4. The trout Mx genes were shown to be differentially expressed in tissues, with high levels of expression of TMG1 (Mx1-4) in blood and TMG2 (Mx5-9) in intestine. The expression of the majority of the trout Mx genes was induced by poly IC in vitro and in vivo, and increased during development. In addition, induction by antiviral (IFN) and proinflammatory cytokines was studied, and showed that type I IFN, IFNγ and IL-1β can induce Mx gene expression in an Mx gene-, cytokine- and cell line-dependent manner. These results show that salmonids possess a large number Mx genes as well as complex regulatory pathways, which may contribute to their success in an anadromous life style.

Carbofuran (CAS) is one of extensively used carbamate pesticides, which is considered as a derivative or a candidate of carbofuran (CAN) for its lower toxicity and persistence. Nevertheless, CAS could be degraded into its toxic metabolites, imposing potential risks on ecological safety. In this paper, biochars, derived from rice straw (RS), chicken manure (CM), corn straw (CS) and tire rubber (TR), were applied in CAS-contaminated soil to explore their effects on the dissipation of CAS and its metabolites. The dissipation rate of CAS was depressed by the amendment of biochar, mainly because biochar inhibited the hydrolysis of CAS by elevating soil pH value. Nevertheless, CS has efficiently enhanced the dissipation of CAN by almost 2-times for its promotion in hydrolysis and biodegradation. CS and CM improved biodegradation by altering the composition and structure of the microbial communities, exhibiting potential for facilitating bioremediation of CAS and CAN. Moreover, steam activated biochar accelerated the dissipation rate by 1.7–2.9 times and 1.3–2.4 times for CAS and CAN, respectively. This study investigated the effects of biochar on CAS and its toxic metabolites as well as possible governing mechanisms, providing rational instruction for biochar application in ambient atmosphere.

Colloidal phosphorus (Pcoll) in soil solutions and subsurface drainage has attracted increasing attention as an additional mobile form of P. A column study was conducted to investigate the effect of biogas slurry (BS) on Pcoll leaching in paddy topsoil (0–20 cm) at rate of 0; 225 m3 ha−1 (55 kg N ha−1, 17 kg P ha−1); 673 m3 ha−1 (165 kg N ha−1, 52 kg P ha−1); 1350 m3 ha−1 (330 kg N ha−1, 104 kg P ha−1) of BS. The colloids particles were separated by microfiltration and ultra-centrifugation processes. Dissolved phosphorus (DP) in leachate ranged from 0.04 to 0.09 mg P L−1 and contributed between 56 and 76% to the total P leaching. Pcoll in leachate ranged from 0.002 to 0.03 mg P L−1 in leachate and contributed between 3 and 26% to TP leaching. Results clearly showed that BS increased Pcoll leaching at medium (673 m3 ha−1: 165 kg N ha−1, 52 kg P ha−1) and high application rate of BS (1350 m3 ha−1: 330 kg N ha−1, 104 kg P ha−1). In contrast, the smallest tested BS application of 225 m3 ha−1 (55 kg N ha−1, 17 kg P ha−1) did not affect Pcoll concentrations in leachates. Significant positive correlations was found between Pcoll and colloidal aluminum (Alcoll), colloidal calcium (Cacoll), total organic carbon (TOCcoll), and with pH, indicating that Al/Ca minerals - organic matter may play a major role as carriers for Pcoll leaching and these processes were pH-dependent. This study confirms that high level of BS application could result in the mobilization of Pcoll from paddy topsoil by leaching.

The inorganic nitrogen concentrations in full-scale anaerobic digestion plants always vary seasonally, challenging the removal stability of microalgal-bacterial consortia in treating piggery digestate. Using a continuous photobioreactor, this study revealed the evolution of bacterial community under inorganic nitrogen fluctuations with influent nitrate loading ranged from 11 to 90 mg-N L−1 and influent ammonium loading ranged from 130 to 550 mg-N L−1. The loading of gradient nitrogen concentrations demonstrated that the optimal removal rate of total inorganic nitrogen was 45.62 mg-N L−1 d−1 along with the total chlorophyll concertation of 19.27 mg L−1, when introducing 240 mg-N L−1 of ammonium and 11 mg-N L−1 of nitrate. High throughput sequencing indicated that the dominant community members for nitrogen removal were shifted from prokaryotic algae to nitrifying and denitrifying bacteria, with nitrate being changed to ammonium. With the increasing influent ammonium loading, the suspended microalgal bacterial consortia gradually changed to microalgal bacterial biofilm, which was attributed to the biofilm-producing prokaryotes Thauera Comamona and Arenimonas. Co-occurrence network analyses illustrated that more functional bacterial modules were formed under ammonium fluctuation. Further correlation test identified influent ammonium loading as the important functional parameter shaping the bacterial community. Overall, this study expands our understanding of the homeostasis in microalgal-bacterial system in the cleaner production of piggery digestate.

Tripartite motif (TRIM) proteins are receiving increased research interest because of their roles in a wide range of cellular biological processes in innate immunity. In zebrafish (Danio rerio), the functions of the finTRIM (ftr) family are unclear. In the present study, we investigated the expression pattern of ftr12, ftr51, ftr67, ftr82, ftr83, and ftr84 in zebrafish for the first time. The results showed that ftr12, ftr67, and ftr84 are maternally expressed in the oocyte and highly expressed at the early stage (0–4 hpf) of embryo (P

Anionic polyacrylamide (PAM) can prevent soil erosion, but its effect on fine particulate phosphorus (P), such as colloidal P, has not been thoroughly examined. The effects of PAM on the release potentials of water-dispersible colloids (WDC) and total P, molybdenum-reactive P (MRP), and molybdenum-unreactive P (MUP) in the colloidal and truly dissolved phases (i.e., TPcoll, MRPcoll, MUPcoll, TPtruly, MRPtruly, and MUPtruly) from six soils across South China were tested in this study. The results showed that the release potentials of TPcoll in the control treatments were 6.9–46.1 mg kg–1 and generally highest in sandy loam soil. Following low (12.5 kg ha-1), middle (25 kg ha-1), and high (50 kg ha-1) levels of PAM application, the release potential of TPcoll decreased by 41.7%, 63.2%, and 77.4% compared to the control group, respectively. Additionally, PAM may trigger MRPcoll and TPtruly releases in sandy loam and/or silt soils, and for most soils, MRPtruly and MUPtruly showed the highest release potentials at middle or high PAM levels. A significant PAM application level by soil site interaction for the release potentials of WDC and colloidal P was observed. Multiple linear regression showed that the PAM rate combined with soil sand content can successfully predict the release potentials of WDC (R2 = 0.552, p < 0.001) and TPcoll (R2 = 0.738, p < 0.001). Our results suggest that PAM can effectively reduce the loss of soil colloids and colloidal P, while its effects are related to both application level and soil texture.

The microalgae-based system has been applied in anaerobic digestate treatment for nutrient removal and biomass production. To optimize its performance in treating piggery digestate, here, commercial bacterial agents, including organic degrading bacteria (Cb) and nitrifying bacteria (Nb), were inoculated into the microalgae-based system dominated by Desmodesmus sp. CHX1 (D). Reactor DN (inoculated with D and Nb) and DCN (inoculated with D, and Cb to Nb at a ratio of 1:2) have better performance on NH4+-N removal, with a final efficiency at 40.26% and 39.87%, respectively, and no NO3−-N or NO2−-N accumulations. The final total chlorophyll concentration, an indicator of microalgal growth, reached 4.74 and 5.47 mg/L in DN and DCN, respectively, three times more than that in D. These results suggested that high NH4+-N removal was achieved by the assimilation into high microalgal biomass after the inoculation with functional bacteria. High-throughput sequencing showed that the richness of microbial community decreased but the evenness increased by inoculating functional microorganisms. Microalgae aggregating bacteria were Cellvibrio, Sphingobacterium, Flavobacterium, Comamonas, Microbacterium, Dyadobacter, and Paenibacillus. This study revealed that the inoculation with functional bacteria reconstructed the microbial community which benefited for the microalgal growth and nutrient removal, providing a promising strategy for treating highly-concentrated digestate.

The effect of no-tillage (NT) on rice yield and nitrogen (N) behavior often varies considerably from individual studies. A meta-analysis was performed to assess quantitatively the effect of NT on rice yield and N uptake by rice, N use efficiency (NUE, i.e., fertilizer N recovery efficiency), and nutrient runoff losses. We obtained data from 74 rice-field experiments reported during the last three decades (1983–2013). Results showed the NT system brought a reduction of 3.8 % in the rice yield compared with conventional tillage (CT). Soil pH of 6.5–7.5 was favorable for the improvement of rice yield with the NT system, while a significant negative NT effect on rice yield was observed in sandy soils (p

Using manure-derived-biochar as an alternative phosphorus (P) source has bright future prospects to improve soil P status. A 98-day microcosm incubation experiment was set up for two soils which were amended with manure biochar at proportions of 0, 0.5% and 1.5%. Swine manure samples were air-dried and manure biochar was prepared by pyrolysis at 400 °C for 4 h. As determined by P-31 nuclear magnetic resonance ((31)P NMR) spectroscopy, manure biochar mainly increased the contents and fractions of orthophosphate and pyrophosphate in two soils, while decreased those of monoesters (P

Biochars derived from rice straw (RS), corn straw (CS), chicken manure (CM) and tire rubber (TR) were applied to soil to investigate their effects on the dissipation of cyazofamid and its metabolite CCIM (4-chloro-5-p-tolylimidazole-2-carbonitrile), with high acute toxicity compared to cyazofamid. The enhancement of cyazofamid dissipation followed the order of CS > RS > CM, whereas TR depressed the cyazofamid dissipation. Adsorption, hydrolysis and microbial degradation were all involved in cyazofamid dissipation. CM and CS enhanced the contribution of biodegradation to cyazofamid dissipation, which might be related with the shifted microbial community. More importantly, CCIM residual was drastically increased by 8–15 times after biochar application, regardless of biochar type. In total, this study shed light on the issue of build-up of metabolites in biochar-amended soil, especially for metabolites having higher toxicities than parent compounds, providing new insights into potential risk of biochar application for soil remediation.

Dabry's sturgeon (Acipenser dabryanus), as a living fossil, is considered a critically endangered aquatic animal in China. To date, the immune system of this species remains largely unknown, with limited available sequence information. In addition, increasing incidence of bacterial pathogenic diseases has been reported. Hence, the present study aimed to characterize comprehensively transcriptome profile of the head kidney from Dabry's sturgeon infected with Aeromonas hydrophila using Illumina platform. Over 42 million high-quality reads were obtained and de novo assembled into a final set of 195240 unique transcript fragments (unigenes), with an average length of 564 bp. Approximately 41702 unigenes were annotated in the NR NCBI database. Dabry's sturgeon unigenes had the highest number of hits with 14365 (34.45%) to Lepisosteus oculatus. The 195240 unigenes were assigned to three Gene Ontology (GO) categories: biological process, cellular component, and molecular function. Among them, 27770 unigenes were clustered into 26 Eukaryotic Orthologous Group (KOG) functional categories, and 36031 unigenes were mapped to 335 known Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. After A. hydrophila administration, 1728 differentially expressed unigenes were identified, including 980 upregulated and 748 downregulated unigenes. Further KEGG enrichment analysis of these unigenes identified 16 immune-related pathways, including the Toll-like receptor signaling pathway, chemokine signaling pathway, complement and coagulation pathway, RIG-I-like receptor signaling pathway, and NOD-like receptor signaling pathway. 20 DEGs were selected and their expression patterns are largely consistent with the transcriptome profile analysis, which clearly validated the reliability of the DEGs in transcriptome analysis. This work revealed novel gene expression patterns of Dabry's sturgeon host defense and contributes to a better understanding of the immune system and defense mechanisms of Dabry's sturgeon in response to bacterial infection. The results provide valuable references for studies in sturgeons that lack complete genomic sequences, and could also be helpful for the analyzing evolution among cartilaginous and teleost fish.

Ammonia oxidation is performed by both ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). Few studies compared the adaptability of AOA and AOB for oxygenated/hypoxic alternant conditions in water-level-fluctuating zones. Here, using qPCR and 454 high-throughput sequencing of functional amoA genes of AOA and AOB, we examined the changes of abundances, diversities, and community structures of AOA and AOB in periodically flooded soils compared to the non-flooded soils in Three Gorges Reservoir. The increased AOA operational taxonomic unit (OTU) numbers and the higher ratios of abundance (AOA:AOB) in the periodically flooded soils suggested AOA have better adaptability for oxygenated/hypoxic alternant conditions in the water-level-fluctuating zones in the Three Gorges Reservoir and probably responsible for the ammonia oxidation there. Canonical correspondence analysis (CCA) showed that oxidation-reduction potential (ORP) had the most significant effect on the community distribution of AOA (p

Converting swine manure to biochar is an effective way to recycle valuable nutrients, but there are few reports on its feasibility as a phosphorus (P) source. The objective of this study was to clarify the unique nature, including P speciation, of manure biochar products under various pyrolysis temperatures. We used solution 31P nuclear magnetic resonance and P K-edge X-ray adsorption near-edge spectroscopy (P XANES) to characterize P species in swine manure biochar. For every 100 °C increment starting from 300 °C, the P content in manure biochar increased by 2.16 to 3.37 g kg-1. However, above 400 °C, organic P species did not appear anymore, and only inorganic P, including orthophosphate and pyrophosphate, existed. P K-edge XANES spectra further showed all biochar samples had higher percentages of Ca3 (PO4)2 and NaP2O7, and lower percentages of FePO4, AlPO4, and inositol hexaphosphate compared to manure. Interestingly, percentages of Ca3(PO4)2, FePO4, and AlPO4 in MB400 (indicating manure pyrolysed at 400 °C) were comparable with those in MB700 while the percentage of NaP2O7 was higher in MB400. Phosphorus release from MB400 maintained a relatively high level at 0.33 g kg-1 during the whole 300-h observation period. These results suggest that with a suitable pyrolysis temperature, it was feasible for manure biochar to be a P source alternative. Graphical abstract ᅟ.

Biochars derived from animal manures may accumulate potentially toxic metals and cause a potential risk to ecosystem. The synchrotron-based X-ray spectroscopy, sequential fractionation schemes, bioaccessibility extraction and leaching procedure were performed on poultry and swine manurederived biochars (denoted PB and SB, respectively) to evaluate the variance of speciation and activity of Cu and Zn as affected by the feedstock and pyrolysis temperature. The results showed that Cu speciation was dependent on the feedstock with Cu-citrate-like in swine manure and species resembling Cu-glutathione and CuO in poultry manure. Pyrolyzed products, however, had similar Cu speciation mainly with species resembling Cu-citrate, CuO and CuS/Cu2S. Organic bound Zn and Zn3(PO4)2-like species were dominant in both feedstock and biochars. Both Cu and Zn leaching with synthetic precipitation leaching procedure (SPLP) and toxicity characteristic leaching procedure (TCLP) decreased greatly with the rise of pyrolysis temperature, which were consistent with the sequential extraction results that pyrolysis converted Cu and Zn into less labile phases such as organic/sulfide and residual fractions. The potential bioaccessibility of Zn decreased for both the PB and SB, closely depending on the content of non-residual Zn. The bioaccessibility of Cu, however, increased for the SB prepared at 300°C–700°C, probably due to the increased proportion of CuO. Concerning the results of sequential fractionation schemes, bioaccessibility extraction and leaching procedure, pyrolysis at 500°C was suggested as means of reducing Cu/Zn lability and poultry manure was more suitable for pyrolysis treatment. Open image in new window

Soil dissolved phosphorus (P) and colloidal P mobilization could be closely related to the degree of phosphorus saturation (DPS). Effects of a wide range of DPS on the distributions of dissolved P and colloidal P in a paddy soil profile were investigated in this study. Dissolved P and colloidal P in water-dispersible soil colloid suspension increased obviously with increasing DPS. The change point of DPS was at 0.12 by using a split-line model. Above the value, dissolved P (3.1 mg P kg −1 ) in soil profile would increase sharply and then transfer downward. Compared with dissolved P, colloidal P was the dominant fraction (78%–91%) of P in soil colloid suspension, and positively related to DPS without a significant change point. The high release of colloids in subsoils with low DPS was attributed to the low ionic strength and high pH value in subsoils. The DPS also had a significant and positive correlation with electrical conductivity (EC), but it showed a negative correlation with pH value. However, the concentration of colloidal P was not greatly correlated to the pH value, EC and optical density of the soil colloid suspension. The results indicated that DPS was an important factor that may affect the accumulation and mobilization of water-extractable colloidal P and dissolved P.

Resource-conserving irrigation and fertilizer management practices have been developed for rice systems which may help address water quality concerns by reducing N and P losses via surface runoff. Field experiments under three treatments, i.e., farmers' conventional practice (FCP), alternate wetting and drying (AWD), and AWD integrated with site-specific nutrient management (AWD + SSNM) were carried out during two rice seasons at two sites in the southwest Yangtze River delta region. Across site years, results indicated that under AWD irrigation (i.e., AWD and AWD + SSNM), water inputs were reduced by 13.4~27.5 % and surface runoff was reduced by 30.2~36.7 % compared to FCP. When AWD was implemented alone, total N and P loss masses via surface runoff were reduced by 23.3~ 30.4 % and 26.9~31.7 %, respectively, compared to FCP. However, nutrient concentrations of surface runoff did not decrease under AWD alone. Under AWD + SSNM, total N and P loss masses via surface runoff were reduced to a greater extent than AWD alone (39.4~47.6 % and 46.1~ 48.3 % compared to FCP, respectively), while fertilizer inputs and N surpluses significantly decreased and rice grain yields increased relative to FCP. Therefore, by more closely matching nutrient supply with crop demand and reducing both surface runoff and nutrient concentrations of surface runoff, our results demonstrate that integration of AWD and SSNM practices can mitigate N and P losses via surface runoff from rice fields while maintaining high yields.

In mammals, interferon regulatory factor 4 (IRF4) plays an important role in the process of development and differentiation of B cells, T cells and dendritic cells. It can regulate immune pathway through IRF5, MyD88, IL21, PGC1α, and NOD2. In the present study, we investigated the expression pattern of IRF4 paralogues and these related genes for the first time in teleosts. The results showed that these genes were all expressed predominantly in known immune tissues while IRF5 was also relatively highly expressed in muscle. IRF4b, IL21, MyD88, IRF5 and NOD2 showed maternal expression in the oocyte and the higher expression of IRF4a, Mx and PGC1α before hatching might be involved in the embryonic innate defense system. Zebrafish embryonic fibroblast (ZF4) cells were infected with GCRV and SVCV. During GCRV infection, the expression of Mx was significantly up-regulated from 3 h to 24 h, reaching the highest level at 12 h (101.5-fold over the controls, P

An Eco-tank system of 10m was designed to simulate the natural river. It consisted of five tanks sequentially connected containing microbes, biofilm carriers and four species of floating aquatic plants. The purification performance of the system for N,N-dimethylformamide (DMF) polluted river water was evaluated by operating in continuous mode. DMF was completely removed in Tanks 1 and 2 at influent DMF concentrations between 75.42 and 161.05mg L-1. The NH4+-N concentration increased in Tank 1, followed by a gradual decrease in Tanks 2-5. Removal of NH4+-N was enhanced by aeration. The average effluent NH4+-N concentration of Tank 5 decreased to a minimum of 0.89mg L-1, corresponding to a decrease of 84.8% when compared with that before aeration. TN concentration did not decrease significantly as expected after inoculation with denitrifying bacteria. The average effluent TN concentration of the system was determined to be 4.58mg L-1, still unable to satisfy the Class V standard for surface water environmental quality. The results of this study demonstrated that the Eco-tank system is an efficient process in removing DMF, TOC, and NH4+-N from DMF polluted river water. However, if possible, alternative technologies should be adopted for controlling the effluent TN concentration.

The toxic effects of Cu (II) present in bamboo industry wastewater (BIWW) upon its anaerobic biodegradability of organic content were investigated. The analysis through the Modified Gompertz model indicated that the optimum chemical oxygen demand (COD) concentration for digestion was 22,780 mg L(-1) with a maximum R(m) (maximum CH(4) production rate) value of 2.8 mL h(-1), corresponding to a specific methanogenic activity (SMA) of 2.38 mL CH(4) g VSS(-1)h(-1). The inhibitory effects of Cu (II) on cumulative methane production depended on its concentration and contact time. Low concentrations (5 mg L(-1)) of Cu (II) showed a stimulating effect on methanogenesis. Methane was not detected when the Cu (II) concentration was increased beyond 300 mg L(-1). The IC(50) value of Cu (II), the Cu (II) concentration that causes a 50% reduction in the cumulative methane production, was 18.32 mg L(-1) (15.9 mg Cu(II) gVSS(-1)).

The combination of bioleaching and electrokinetic remediation has been proved to be an effective method to remove heavy metals from municipal sewage sludge. The results showed that using electrokinetic remediation for six days after bioleaching for four days, the contents of Cu and Zn in sewage sludge decreased from 296.4 mg kg − 1 and 3756.2 mg kg − 1 to 63.4 mg kg − 1 and 33.3 mg kg − 1 , respectively, which could meet the Chinese standard for land application of the heavy metals in sewage sludge. During the bioleaching process, both the organic sulfide fraction of Cu and the carbonate-bound and organic sulfide fractions of Zn transformed to soluble and ionic fractions which could easily migrate to the electrode zone and then accumulate there, Finally, the soluble and ionic fractions of these heavy metals could be disposed of or recycled expediently at the end of electrokinetic remediation.

An enhanced EK (electrokinetic) process for the removal of heavy metals from an electroplating sludge was performed by adding electrolytes in electrode chambers. The EK experiments were conducted under a constant cell potential (32 V) for 5 days using tap water (TW) and aqueous solution containing sodium dodecylsulfate (SDS) and citric acid (CA) as electrolytes. The results indicated the removal efficiency of heavy metals using TW and aqueous solution containing SDS and CA as electrolytes were 20–51%, 26–65% and 34–69%, respectively, the highest metal removal performance was found using CA as electrolyte. And the removal efficiency of the five metals from sludge in all the EK experiments was Cr > Zn > Ni > Cu > Pb. And sequential extraction analysis revealed that the binding forms of heavy metals with sludge highly depended on the electrolytes, changed from the most difficult extraction type (residual form) to the easier extraction types (soluble, exchangeable, sorbed, sulfate and carbonate forms) after electrokinetic process.

To investigate the effect of the transit through the gut of earthworm (Eisenia fetida) on the fractionation of Cu and Zn in pig manure, earthworms were reared with pig manure in the greenhouse. Both the pig manure and the earthworm casts were subjected to a five-step sequential extraction of Cu and Zn. The content of Cu bound to organic matter in pig manure increased from 60% to 75% after transit through the gut of earthworm, whereas that of Zn decreased from 50% to 25%. It demonstrated that Cu had a strong affinity towards organic matter. The share of Cu and Zn in the exchangeable fraction was reduced by the transit through the gut of earthworm. Based on these changes, Cu was more bioavailable, whereas Zn was less bioavailable. The factors affecting metal fractionation, like pH, organic matter (OM) and total phosphorous (TP) contents, and total metal concentration, were also affected significantly by the transit through the gut of earthworm. Stepwise multiple regression analysis revealed that the fractionation of Cu in the earthworm casts was influenced by OM, TP and the amount of Cu in the earthworm casts. The total Zn concentration in the earthworm casts was the primary factor that explained most of the variation in Zn fractionation. The present study demonstrated that the digestive activity in the gut of E. fetida played an important role in the fraction redistribution of Cu and Zn in pig manure.

The content and speciation of heavy metals in composted sewage sludge is the main cause of negative impacts on environment and health of animal and human. An aerobic composting procedure was conducted to investigate the influences of some key parameters on phytotoxicity and speciation of Cu, Zn and Pb during sewage sludge composting. The pH value reached the optimal range for development of microorganisms, and content of organic matter (OM) and dissolved organic carbon (DOC) decreased with the composting age. The total amounts of Cu, Zn and Pb were much lower in the final compost. The results from sequential extraction procedure of heavy metals showed that composting process changed the distribution of five fractions of Cu, Zn and Pb, and reduced the total contents and sum percentages of four mobile fractions (exchangeable (EXCH), carbonate (CAR), reducible iron and manganese (FeMnOX), and organic matter bound (OMB)), indicating that the metal mobility and phytotoxicity decreased after aerobic composting. The seed germination and root growth of Pakchoi ( Brassica Chinensis L.) were enhanced with composting age and reached the highest value at the end of compost. The decrease of OM and DOC was significantly correlated to changes of metal distribution and germination index (GI) of Pakchoi. Only for Cu in the compost, the GI could be predictable from the sum mobile metal fractions (EXCH + CAR + FeMnOX + OMB) ( R = −0.814 * ). For Zn and Pb, R value was significantly increased by use of other components, such as pH, OM and DOC, which suggested that the transformation of heavy metal speciation and phytotoxicity of sewage sludge during an aerobic composting was rather strongly dependent on multiple components than a single element.

Increasing nitrogen oxides (NOx) emissions over the fast developing regions have been of great concern due to their critical associations with the aggravated haze and climate change. However, little geographically specific data exists for estimating spatio-temporal trends of NOx emissions. In order to quantify the spatial and temporal variations of NOx emissions, a spatially explicit approach based on the continuous satellite observations of artificial nighttime stable lights (NSLs) from the Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) was developed to estimate NOx emissions from the largest emission source of fossil fuel combustion. The NSL based model was established with three types of data including satellite data of nighttime stable lights, geographical data of administrative boundaries, and provincial energy consumptions in China, where a significant growth of NOx emission has experienced during three policy stages corresponding to the 9th-11th)Five-Year Plan (FYP, 1995-2010). The estimated national NOx emissions increased by 8.2% per year during the study period, and the total annual NOx emissions in China estimated by the NSL-based model were approximately 4.1%-13.8% higher than the previous estimates. The spatio-temporal variations of NOx emissions at city scale were then evaluated by the Moran's I indices. The global Moran's I indices for measuring spatial agglomerations of China's NOx emission increased by 50.7% during 1995-2010. Although the inland cities have shown larger contribution to the emission growth than the more developed coastal cities since 2005, the High-High clusters of NOx emission located in Beijing-Tianjin-Hebei regions, the Yangtze River Delta, and the Pearl River Delta should still be the major focus of NOx mitigation. Our results indicate that the readily available DMSP/OLS nighttime stable lights based model could be an easily accessible and effective tool for achieving strategic decision making toward NOx reduction.

In this paper, downward movement of phosphorus and copper as dredged sediment applied on sandy loam soil was studied by column leaching experiments. Three sediment application rate, (i.e., 1, 2 and 5-cm depth of sediments) were applied to the top of the soil columns. Two and a half months leaching experiments were conducted, which include a 15-day un-watered period. Concentrations of phosphorus and copper in the leachate and the vertical distribution of Olsen-P and diethylenetriaminepentaacetic acid (DTPA) extractable Cu in the soil columns were determined. The results showed that, un-watered period could increase the downward movements of phosphorus and copper. Sediment application significantly increased Olsen-P concentration in the top 15 cm of the soil columns, but has not significantly affected that in the deeper soil layer. The 1-cm depth sediment treatment did not increase the DTPA extractable Cu concentration in the whole soil column. The 5-cm depth sediment treatment, however, significant increased the DTPA extractable Cu in the deeper soil layers. This study suggested that the application of dredged sediment laden with P and Cu on sandy loam soil might cause the significant downward movement of phosphorus and copper.

The effects of cadmium stress on nodulation, N 2 -fixation capabilities of the root nodule, the change in ultrastructure of the root nodule, soybean growth, and the distribution of cadmium in plants were studied. The results obtained show that the nodulation of soybean roots was greatly inhibited by the addition of Cd, especially at the addition level of 10 and 20 mg kg −1 soil. The inhibition of plant growth, especially the root growth, increased as the cadmium concentration increased, with deleterious effects observed for the roots. The weight ratio of soybean root/leaf decreased as the Cd concentration increased, which might explain the reason for nodulation decreases. The results also indicate that N 2 -fixation of root nodule was stimulated to some extent at the low levels of Cd addition, but decreased sharply with further increase of the Cd concentration. High Cd levels were also associated with changes in the ultrastructure of root nodule, in which the effective N 2 -fixing area was reduced and the N 2 -fixing cells in the area also reduced. In addition, the results also reveal that the content of Cd in different parts of the plants was as follows: roots≫stems>seeds, indicating that the accumulation of Cd by roots is much larger than that by any other part of the soybean plant, and might cause deleterious effects to root systems.

Adsorption and hydroponics experiments were conducted to study the role of citric acid on the phytoremediation of heavy metal contaminated soil. The results show that addition of citric acid decreased the adsorption of both lead and cadmium, such an effect was bigger for cadmium than for lead. The decrease in the adsorption of Pb and Cd was mainly due to a decrease of pH in the presence of citric acid. The presence of citric acid could alleviate the toxicity of Pb and Cd to radish, and stimulate their transportation from root to shoot. The studies of heavy metal forms using sequential extraction demonstrated that lead was mainly existed as FHAC (a lower bioavailable form) in the root, while F(HCl) was the dominant form in the leaf. The addition of citric acid to the soil changed the concentration and relative abundance of all the forms. The detoxifying effect of citric acid to Pb in shoots might result from the transformation of higher toxic forms into lower toxic forms. Cadmium was mainly present as F(NaCl), therefore, it had higher toxicity than lead. The addition of citric acid increased the abundance of F(H2O) + F(NaCl), indicating that citric acid treatment could transform cadmium into more transportable forms.

The present study employed ozonation process to treat the bamboo industry wastewater (BIWW). The impact of ozone dosage and initial organic concentration on color, COD and TOC removal rates were studied along with characterization of the major organics in raw and treated wastewater. The results suggested the ozone dosage of 3.15 g h(-1) (concentration 52.5 mg L(-1)) was suitable for the treatment. After 25 min ozonation of 1L raw wastewater, the color, COD and TOC removal efficiencies were 95%, 56% and 40%, respectively, with an influent COD concentration of 835 mg L(-1). The ratio of kg O(3) kg(-1) COD at 3.15 g h(-1) was 2.8 (3), revealing that ozonation was a cost effective process for tertiary treatment of BIWW. Longer oxidization time was required to achieve similar results for raw wastewater with higher COD concentration. The chromatogram from gel permeation chromatography revealed that ozonation resulted in the breakdown of high molecular weight compounds into lower molecular weight components but could not completely mineralize the organic matter. The majority of these compounds were identified in both raw and ozonated samples via GC-MS analysis. In addition to ester derivatives as the main intermediates of ozonation, 1-chloroctadecane, methyl stearate, benzophenone and α-cyperone were identified as the by-products of ozonation.

To investigate the effect of water-dispersible colloids derived from swine manure on the potential risks of phosphorus (P), migration behavior of P in saturated-flow columns was compared in the presence and absence of water-dispersible colloids of manure in influent. It was found that dissolved phosphorus (DP) accounted for a majority of total P (65-98%) in the effluent with deionized water treatments, while contributed between 21 and 45% to total P leaching with the manure colloid treatments. In manured soils, with the inflow of manure colloidal suspension, colloidal P in the effluent were 26.7 times higher than that of deionized water treatment (PM+W) and 1.9 times more than that of unamended soil treated with manure colloid (P0+M) in the end of the leaching experiment. Despite the initial reduction of DP concentrations in the effluent with the presence of manure colloid, the DP concentrations still increased smoothly and continued to transport with the effluent throughout the breakthrough experiment. This suggested that P sorption sites of the soil and the added manure colloid in the column were fastly saturated during initial stage of the experiment. In manure colloid treatments, higher colloidal P concentrations in leachate were related to larger P contents of leached colloids, which were in sorption equilibrium with larger concentrations of dissolved P. Furthermore, in deionized water treatments, good linear correlation between colloidal P and colloidal Fe indicated that Fe hydroxides could be served as a main medium for the transportation of colloidal P. Key words: Dissolved P, colloidal P, water-dispersible colloids, manure, degree of phosphorus saturation (DPS).

Nitrate enrichment in groundwater is a worldwide phenomenon, and the removal of nitrate from groundwater has raised ever-increasing concerns due to severe impacts of nitrate on human and animal health. A bioelectrochemical method for treatment of simulated nitrate-contaminated groundwater was investigated using a biofilm-electrode reactor (BER). Effects of different currents on the transformation of nitrate to nitrogen were investigated. The nitrate removal efficiency was dependent on the current. When the current was lower than 78mA, the nitrate removal efficiency was linearly related to the current, and a portion of the nitrate was transformed to nitrite or ammonium. The maximum nitrate removal efficiency 87% was achieved at the current of 78 mA and the given operation condition. The BER could be operated efficiently at the current of 78mA, but further increase the current did not offer significant performance promotion.

To demonstrate the potential risks associated with the application of solid agricultural wastes, we investigated Cu distribution in water-dispersible colloids derived from swine manure and its transport through quartz sand. Samples were sequentially centrifuged to obtain five colloid suspensions (10,1,0.45,0.2, and0.02 μm) and four colloid subsamples (1-10, 0.45-1, 0.2-0.45, and 0.02-0.2 μm). We observed that 2% of Cu in the swine manure was found in the 0.02-10 μm colloid fractions, while 18% was observed in the0.02 μm colloid suspension. The highest accumulation of Cu was found in the 0.02-0.2 μm fraction of colloids, in which organic carbon was the major component. The Cu in the 1-10 μm colloid fraction existed in both inorganic compounds and organic associations, whereas it mainly existed as organic complexes in colloids1 μm (0.53 μm, specifically). Furthermore, large colloids (1-10 μm) of swine manure were partially filtered out as they passed through the sand particles, and fine colloids facilitated the transport of Cu. The formation of organic complexes was hypothesized to enhance the mobility of Cu. Further research is needed to incorporate our experimental findings into a realistic model of particle mobilization and transport through soil or groundwater aquifers.

The study investigated the bioaccumulation of Cu, Zn, Pb and Cd in Eisenia fetida fed on pig manure in greenhouse, and its relationship to bioavailability of these elements in pig manure. Metals in exchangeable, carbonates-bound and Fe–Mn oxides-bound fractions obtained by sequential extraction were considered to be bioavailable. The bioaccumulation factors (BAFs) of E. fetida to heavy metals were Cd (2.749 ± 0.441), Zn (0.594 ± 0.200), Pb (0.274 ± 0.101) and Cu (0.076 ± 0.030). Variations in the Pb and Cd concentrations of E. fetida were best explained by the concentration of exchangeable fraction, while that of Cu was best explained by the concentrations of exchangeable and Fe–Mn oxides-bound fractions. The concentration of Zn in E. fetida depended strongly on the concentrations of exchangeable, carbonates-bound and Fe–Mn oxides-bound fractions. Further nonlinear regression analysis revealed the positive logarithmic relationship between the BAF and the exchangeable metal concentration of pig manure.

An undisturbed heavy clay soil column experiment was conducted to examine the influence of the new nitrification inhibitor, 3,4-dimethylpyrazole phosphate (DMPP), on nitrogen and soil salt-ion leaching. Regular urea was selected as the nitrogen source in the soil. The results showed that the cumulative leaching losses of soil nitrate-N under the treatment of urea with DMPP were from 57.5% to 63.3% lower than those of the treatment of urea without DMPP. The use of nitrification inhibitors as nitrate leaching retardants may be a proposal in regulations to prevent groundwater contaminant. However, there were no great difference between urea and urea with DMPP treatments on ammonium-N leaching. Moreover, the soil salt-ion leaching losses of Ca2+, Mg2+, K+, and Na+ were reduced from 26.6% to 28.8%, 21.3% to 27.8%, 33.3% to 35.5%, and 21.7% to 32.1%, respectively. So, the leaching losses of soil salt-ion were declined for nitrification inhibitor DMPP addition, being beneficial to shallow groundwater protection and growth of crop. These results indicated the possibility of ammonium or ammonium producing compounds using nitrification inhibitor DMPP to control the nitrate and nutrient cation leaching losses, minimizing the risk of nitrate pollution in shallow groundwater.

DMPP (3,4-dimethylpyrazole phosphate) has been used to reduce nitrogen (N) loss from leaching or denitrification and to improve N supply in agricultural land. However, its impact on soil nitrifying organisms and enzyme activities involved in N cycling is largely unknown. Therefore, an on-farm experiment, for two years, has been conducted, to elucidate the effects of DMPP on mineral N (NH4(+)-N and NO3(-)-N) leaching, nitrifying organisms, and denitrifying enzymes in a rice-oilseed rape cropping system. Three treatments including urea alone (UA), urea + 1% DMPP (DP), and no fertilizer (CK), have been carried out. The results showed that DP enhanced the mean NH4(+)-N concentrations by 19.1%--24.3%, but reduced the mean NO3(-)-N concentrations by 44.9%--56.6% in the leachate, under a two-year rice-rape rotation, compared to the UA treatment. The population of ammonia oxidizing bacteria, the activity of nitrate reductase, and nitrite reductase in the DP treatment decreased about 24.5%--30.9%, 14.9%--43.5%, and 14.7%--31.6%, respectively, as compared to the UA treatment. However, nitrite oxidizing bacteria and hydroxylamine reductase remained almost unaffected by DMPP. It is proposed that DMPP has the potential to either reduce NO3(-)-N leaching by inhibiting ammonia oxidization or N losses from denitrification, which is in favor of the N conversations in the rice-oilseed rape cropping system.

A field experiment located in Taihu Lake Basin of China was conducted, by application of urea or a mixture of urea with manure, to elucidate the interception of nitrogen (N) export in a typical rice field through "zero-drainage water management" combined with sound irrigation, rainfall forecasting and field drying. N concentrations in floodwater rapidly declined before the first event of field drying after three split fertilizations, and subsequently tended to return to the background level. Before the first field drying, total particulate nitrogen (TPN) was the predominant N form in floodwater of plots with no N input, dissolved inorganic nitrogen (DIN) on plots that received urea only, and dissolved organic nitrogen (DON) on plots treated with the mixture of urea and manure. Thereafter TPN became the major form. No N export was found from the rice field, but total nitrogen (TN) of 15.8 kg/hm2 was remained, mainly due to soil N sorption. The results recommended the zero-drainage water management for full-scale areas for minimizing N export.

Some of the major factors influencing ammonia volatilisation in a rice wheat rotation system were studied. A continuous airflow enclosure method was used to measure NH3 volatilisation in a field experiment at an agricultural college in Jiangsu Province. The five treatments comprised application rates of 0, 100, 200 or 300 kg N ha(-1) as urea, per growing season with rice straw amendment when wheat was sown, and 200 kg N ha(-1) without rice straw amendment. There were three replicates in a randomised block design. Ammonia volatilisation was measured immediately after urea application in the three consecutive years 1995 to 1997. The results show that N losses through NH3 volatilisation accounted for 4-19% of N applied during the wheat growing season and for 5-11% during the rice growing season. Ammonia volatilisation was affected significantly by soil moisture and temperature before and after fertiliser application during the wheat growing season. The ratio of volatilised NH3-N to applied N after urea application during the rice growing season was as follows: top-dressing at the onset of tillering > top-dressing at the start of the booting stage > basal fertilization. The results also show that the amount of N lost through NH3 volatilisation increased with increasing N application rate, but the ratio to applied N was not affected significantly by N application rate. Amendment with rice straw had no significant effect on NH3 volatilisation.