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Excessive nitrogen (N) fertilization in agroecological systems increases nitrous oxide (N 2 O) emissions. 3,4-dimethylpyrazole phosphate (DMPP) is used to mitigate N 2 O losses. The influence of DMPP efficiency on N 2 O mitigation was clearly affected by spatiotemporal heterogeneity. Using field and incubation experiments combined with metagenomic sequencing, we aimed to investigate DMPP efficiency and the underlying microbial mechanisms in dark-brown (Siping, SP), fluvo-aquic (Cangzhou, CZ; Xinxiang, XX), and red soil (Wenzhou, WZ) from diverse climatic zones. In the field experiments, the DMPP efficiency in N 2 O mitigation ranged from 51.6% to 89.9%, in the order of XX, CZ, SP, and WZ. The DMPP efficiency in the incubation experiments ranged from 58.3% to 93.9%, and the order of efficiency from the highest to lowest was the same as that of the field experiments. Soil organic matter, total N, pH, texture, and taxonomic and functional α-diversity were important soil environment and microbial factors for DMPP efficiency. DMPP significantly enriched ammonia-oxidizing archaea (AOA) and nitrite-oxidizing bacteria (NOB), which promoted N-cycling with low N 2 O emissions. Random forest (RF) and regression analyses found that an AOA (Nitrosocosmicus) and NOB (Nitrospina) demonstrated important and positive correlation with DMPP efficiency. Moreover, genes associated with carbohydrate metabolism were important for DMPP efficiency and could influenced N-cycling and DMPP metabolism. The similar DMPP efficiency indicated that the variation in DMPP efficiency was significantly due to soil physicochemical and microbial variations. In conclusion, filling the knowledge gap regarding the response of DMPP efficiency to abiotic and biotic factors could be beneficial in DMPP applications, and in adapting more efficient strategies to improve DMPP efficiency and mitigate N 2 O emissions in multiple regions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

To investigate nitrate and nitrite content in fresh vegetables, 264 samples were randomly collected in the farmers' markets in Shanghai, Southeast China. The results indicate that 25.0% of the fresh vegetables were critically or more contaminated by nitrate [>1440 mg/kg FW (Fresh weight)]. Generally, leafy vegetables were more highly enriched in nitrate than root-tuber and fruit vegetables. About 22.6% of the leafy vegetables had a nitrate content exceeding the limit for edible permission (>3000 mg/kg FW). Nitrite content in the fresh vegetables was all within the safe level (<1 mg/kg FW). It was estimated that the daily nitrate intake through eating vegetables in Shanghai exceeded the WHO/FAO allowable limit. The field experiment indicated that the hyper-accumulation of nitrate and nitrite in the vegetables was mainly attributed to the excessive application of chemical fertilizers. The maxima of nitrate and nitrite in the vegetables were attained one week after applying chemical fertilizer, and thus they cannot be picked for dietary use. Applying organic manure can effectively lower the risk of nitrate and nitrite contamination in vegetables. The old leaves and leaf petioles were more easily enriched in nitrate due to their weaker metabolic activity. Vegetables with high nitrate content had a high risk of nitrite toxicity during storage due to the biological conversion of nitrate into nitrite, which is easily triggered by suitable temperature and mechanical damage processing. Therefore, fresh vegetables should be stored by rapid cooling and in undamaged forms to prevent nitrite accumulation.

Agriculture-related nonpoint source pollution has been a worldwide issue in the past few decades. Estimating pollutant sources at the basin scale remains a challenge due to the complexity of pollutant transport mechanisms affected by land use, variable climatic condition, geological formation, and lack of long-term observation data. This study was based on the long-term plot observational data of surface runoff and water quality and used principal component analysis and other statistical analyses to analyze the variation of water quality affected by different land uses (cropland, tree forest, shrub, grassland, and wildland). The mean concentration method with the local calibrated/verified SWAT (soil and water assessment tool) model was used to quantify the load of nonpoint source (NPS) pollutants on slope areas under different land uses in the Anjiagou Watershed. Our research results determined permanganate index (COD Mn ), ammonia nitrogen (NH 3 -N), total nitrogen (TN), fluoride (F - ), nitrite nitrogen (NO 2 -N), total phosphorus (TP), and hexavalent chromium (Cr 6+ ) as the significant pollutants while 5-day biochemical oxygen demand (BOD 5 ) was identified to be below the water quality standards of Grade V (water for agricultural and general landscape use) in the studied watershed. Pollutants were discharged through either hillslope at a total rate of 2.4 kg ha -1 , accounting for 67.6% of the total, or through waterway channels (32.4%). The pollutant concentrations were from 23.5 mg L -1 to 37.4 mg L -1 , varying with pollutants and land uses. All examined water quality indicators exceeded the minimum safety standards defined by the regulations of the Gansu provincial government by averaging 3.5 times higher than the safety threshold. The pollutants from hillslopes exceeded water quality standards by a factor of 3.4-4.4 times compared with from the waterway channel by 1.9. Implementing soil and water conservation measures can mitigate pollutants to some extent, particularly during the process of highland runoff converging into waterways. At the watershed level, between 33 and 38% of the runoff and pollutants were discharged from croplands, between 59 and 66% from forest land, < 2% from grassland, and 1% from wildland. This study also demonstrates a simple but novel method to estimate NPS pollutants using long-term plot observations in conjunction with SWAT models, which can be used in other watersheds with similar conditions., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

To examine the safety of Chinese traditional fermented fish products (CTFPs) available on the Chinese market, nitrite, nitrate, biogenic amines (BAs) and volatile N- nitrosamines (VNAs) content in 33 commercial CTFPs from different provinces was investigated. The mean content of nitrite and nitrate wase 0.63 and 749.5 mg/kg, respectively. Concerning the occurrence of BAs, the accumulation in all CTFPs samples remained at low levels, whereas only in one sample from Guangxi the histamine content exceeded the critical level (50 mg/kg). In addition, six types of VNAs, including N- nitrosodimethylamine (NDMA), N -nitrosoethylmethylamine, N -nitrosopiperidine, N -nitrosopyrrolidine, N -nitrosomorpholine and N -nitrosodiphenylamine, were detected in a high number of samples. The NDMA content in 36.4% of the samples and the total VNAs content in about 63.6% of the samples were unacceptable. Principal component analysis indicated that the accumulation of NDMA and total VNAs was closely related with the content of histamine, tyramine and nitrate.

Biogenic amines (BAs) and nitrites are both considered harmful compounds for customer health, and are closely correlated with the microorganisms in fermented mustard (FM). In this study, BAs and nitrite contents in fifteen FM samples from different brands were analyzed. The concentrations of cadaverine in one sample and of histamine in one sample were above the toxic level. Moreover, five FM samples contained a high level of nitrite, exceeding the maximum residue limit (20 mg/kg) suggested by the National Food Safety Standard. Then, this study investigated bacterial and fungal communities by high-throughput sequencing analysis. Firmicutes and Basidiomycota were identified as the major bacteria and fungi phylum, respectively. The correlations among microorganisms, BAs and nitrite were analyzed. Typtamine showed a positive correlation with Lactobacillus and Pseudomonas . Cadaverine and nitrite is positively correlated with Leuconostoc . Furthermore, thirteen strains were selected from the samples to evaluate the accumulation and degradation properties of their BAs and nitrite. The results indicated that the Lactobacillus isolates, including L. plantarum GZ-2 and L. brevis SC-2, can significantly reduce BAs and nitrite in FM model experiments. This study not only assessed the contents of BAs and nitrite in FM samples, but also provided potential starter cultures for BAs and nitrite control in the FM products industry.

Particulate nitrite is a critical source of hydroxyl radicals; however, it lacks high-resolution methods due to its low abundance and stability to explore its formation mechanism. In this study, a modified versatile aerosol concentration enrichment system (VACES) coupled with ion chromatography (IC) was used to measure particulate NO 2 - hourly online and achieve a lowered detection limit of 10 -3 μg m -3 . VACES-IC was used to observe a high- and low-concentration events of PM 1.0 -NO 2 - in Shanghai, corresponding to the ambient-level concentrations of 0.34 and 0.05 μg m -3 , respectively. The morning peak concentrations of NO 2 - even exceeded 3σ (standard deviation) in the high-concentration event due to the reduction of NO 2 by aerosol SO 3 2- based on kinetics and regression analysis. This implies that controlling SO 2 emissions would be an effective strategy to decrease morning NO 2 - concentrations, correspondingly reducing the kinetic formation of SO 4 2- by 20.8-34.8%. However, after sunrise, NO 2 - formation was primarily attributed to NO 2 hydrolysis at pH 4.97-6.14. In the low-concentration event, NO 2 hydrolysis also accounted for an overwhelming proportion (∼90%) of NO 2 - formation. This work estimates the contribution of different paths to particulate NO 2 - formation based on newly established high-resolution measurements.

This article explored the positive effects of partial replacement of sodium nitrite by Lactobacillus plantarum on reducing nitrite and biogenic amine content, improving color and gel structure of Chinese fermented sausages. The results indicated that the strain had nitrate and nitrite reductase activities, which can reduce nitrate and nitrite. And the final reduction products of nitric oxide can react with myoglobin to generate pink nitrosylmyoglobin (Mb(Fe 2+ )-NO), which can improve sausage color. Dynamic rheological test showed that the strain improved viscoelasticity and gel properties of the samples. Low field nuclear magnetic resonance (LF-NMR) measurement illustrated that the strain enhanced immobilised water in myofibrillar network of the sausages. The protein gels were improved by changes of C-H stretching and bending vibrations, reduction of α-helix and increase of β-sheet and random coil in secondary structure, changes of microenvironment in tertiary structure. Analysis of biogenic amines showed that the strain reduced risk from biogenic amines by reducing tyramine content. Overall, our findings demonstrated that combination of L. plantarum and low levels of sodium nitrite could be a potential strategy to produce high-quality, healthier sausage by lowering nitrite and biogenic amine levels, improve color and gel properties of Chinese fermented sausages., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Variations in the taste quality of no-added-nitrite Chinese bacon (unsmoked) during processing were investigated using 1 H-NMR and multivariate data analysis. The results showed that 21 metabolites were dominant during processing, which involved marinating, air-drying, fermentation, and baking, including amino acids, sugars, organic acids, nucleic acids and their derivatives, and alkaloids. The contents of isoleucine, leucine, valine, alanine, acetate, glutamate, succinate, glycine, sucrose, tyrosine, and phenylalanine increased continuously throughout the process. The lactate, creatine, carnosine, betaine, taurine, hypoxanthine, and AMP contents all significantly increased after baking; the inosine content significantly increased after fermentation and then decreased; the histamine content significantly increased after air-drying and then decreased; and the histidine content decreased. Each processing treatment promoted taste formation in no-added-nitrite Chinese bacon (unsmoked), especially baking. The baking point owned relatively higher levels of metabolites and sensory evaluation compared to other treatments. Sensory evaluation revealed that the ultimate taste of Chinese bacon (unsmoked) at the end of baking tended toward umami (glutamate), sweetness (AMP), and sourness (lactate). The first and second principal components explained 74.0% and 13.4% of the variables, respectively. These findings indicated the potential of NMR-based metabolomics for assessing the taste quality of no-added-nitrite Chinese bacon (unsmoked), which could contribute to a better understanding of taste compound changes in meat products. PRACTICAL APPLICATION: Nitrite is commonly used in Chinese bacon (unsmoked), but excessive intake is not good for human health. Nitrite has been replaced with nitrite substitutes to prepare no-added-nitrite Chinese bacon (unsmoked). The metabolites of no-added-nitrite Chinese bacon (unsmoked) were detected to determine the key treatment that contributes to the formation of taste during processing. This study determined the main taste components of no-added-nitrite Chinese bacon (unsmoked) and its formation process, which provides new insight into the production and characteristics of flavor in Chinese bacon (unsmoked)., (© 2020 Institute of Food Technologists®.)

It was well established that microbial communities are the major drive for the formation of arsenic-contaminated groundwater. However, it remains to be elucidated for how nitrate/nitrite affects the microorganisms-catalyzed dissolution and reduction of arsenic. To address this issue, we collected soil samples containing high-contents of arsenic from the Shimen Realgar Mine area. Microcosm assay indicated that addition of nitrate/nitrite significantly inhibited the dissolution, reduction and release of As and Fe caused by the biological catalysis of microbial communities in the soils, meanwhile nitrate/nitrite was reduced into N 2 . To further investigate the molecular mechanism of this finding, we used a representative dissimilatory arsenate-respiring strain Shewanella sp. GL90 from the soils to perform the arsenic release assay. GL90 can efficiently catalyze the reductive dissolution, and promote the release of As and Fe in soils. It is interesting to see that the addition of nitrate/nitrite to the soils led to marked decreases in the GL90-mediated dissolution of As and Fe in the soils. Moreover, we found that this finding was attributed to that nitrate/nitrite significantly inhibited the transcription of the gene of the respiratory arsenate reductase protein in GL90 cells. This work provided new insights into the mechanisms for the coupling of As, N and Fe geochemical cycles in arsenic-rich soils, and for how environmental factors affect As concentration in groundwater.

Anammox are unusual members of the microbial community contributing to N losses via anaerobic ammonium oxidation. Anammox use nitrite as a substrate and produce hydrazine as an intermediate product. Up to date, the effects of dissolved oxygen and moisture dynamics on anammox potential and microbial community in agricultural soils were poorly understood. In this study, we investigated the interaction of dissolved oxygen and moisture contents as factors affecting the soil anammox process. The experiment had four fertilization treatments i.e. Control (CK), Chemical fertilizer (CF), Pig composted manure plus chemical fertilizer (PMCF), and Straw returned to soil plus chemical fertilizer (SRCF) with different water contents, 70%-FC, Alternate wetting and drying (AWD), Flooding I (D.O 5.8 mg L -1 ), and Flooding II (D.O 2.6 mg L -1 ). 15 N-isotopic tracer technique was used to evaluate the anammox and denitrification rates. The results showed that the anammox rate ranged from the lowest 0.56 nmol N 2 ·g -1 ·h -1 in CF (with 70% FC water) to the highest rate of 1.47 nmol N 2 ·g -1 ·h -1 in SRCF (with flooding II). In water treatments, the average lowest and highest anammox rates were in the 70% FC (0.61 nmol N 2 ·g -1 ·h -1 ) and Flooding II (1.14 nmol N 2 ·g -1 ·h -1 ), respectively. Moreover, under soil treatments, the minimum average anammox rate was found in the PMCF (0.76 nmol N 2 ·g -1 ·h -1 ) and maximum in the SRCF (1.01 nmol N 2 ·g -1 ·h -1 ). Interestingly, anammox genes copy numbers were highest in alternate wetting and drying conditions under all fertilizer treatments rather than in continuous flooding. The phylogenetic analysis showed that Ca. Brocadia was dominating while some of Ca. Jettenia was also present. In conclusion, alternate wetting and drying could increase the number of anammox bacteria and microbial diversity., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Pao cai is a spontaneously fermented cabbage where native bacteria may have an important influence on nitrite content during fermentation. In this research, we used metagenomic-based 16S rRNA gene amplicon sequencing to analyze differences in bacterial composition of pao cai from Hohhot City (northern China) and Guiyang City (southern China). Alongside this, metagenome functional features from the 16S rRNA genes of the microbiome were predicted and correlated with the nitrite content of pao cai. Nitrite-reducing bacterial genera were identified including Lactobacillus (73.37%), Pediococcus (0.93%), Acinetobacter (0.74%), Leuconostoc (0.31%), Weissella (0.14%), Streptococcus (0.09%), Megamonas (0.08%), Enterococcus (0.07%), and Alistipes (0.06%). Lactobacillus was the predominant genus in both the northern and the southern pao cai samples and was significantly negatively correlated with nitrite content; it was more abundant in southern samples than northern samples. Based on determination of alpha and beta diversities of the microbiome in samples, differences in the microbiome of northern and southern pao cai were demonstrated that may influence nitrogen metabolism. This research suggests that 16S rRNA gene amplicon sequencing is an effective way to comprehensively study the microbes with potential nitrite formation or decomposition ability instead of investigating the individual bacterial genera., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The objective of this study was to explore the controlling factors on the migration and transformation of nitrogenous wastes in groundwater using long-term observations from a contaminated site on the southwestern edge of the Tengger Desert in northwestern China. Contamination was caused by wastewater discharge rich in ammonia. Two long-term groundwater monitoring wells (Wells 1# and 2#) were constructed, and 24 water samples were collected. Five key indicators were tested: ammonia, nitrate, nitrite, dissolved oxygen, and manganese. A numerical method was used to simulate the migration process and to determine the migration stage of the main pollutant plume in groundwater. The results showed that at Well 1# the nitrogenous waste migration process had essentially been completed, while at Well 2# ammonia levels were still rising and gradually transitioning to a stable stage. The differences for Well 1# and Well 2# were primarily caused by differences in groundwater flow. The change in ammonia concentration was mainly controlled by the migration of the pollution plume under nitrification in groundwater. The nitrification rate was likely affected by changes in dissolved oxygen and potentially manganese., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Characteristics and transformation of nitrous acid (HONO) and particulate nitrite were investigated with high time-resolution field measurements at an urban site in Ji'nan, China from Nov. 2013 to Jan. 2014. During the sampling period, averages of 0.35ppbv HONO and 2.08μgm(-3) fine particulate nitrite were observed. HONO and particulate nitrite exhibited similar diurnal variation patterns but differed in the time at which concentration peaks and valleys occurred. Elevated nocturnal HONO concentration peaks were mainly associated with primary emissions from vehicle exhaust and secondary formation via heterogeneous reactions of NO2. In fresh air masses dominated by vehicle emissions, the average HONO/NOx ratio was 0.58%. The nocturnal heterogeneous reactions of NO2 contributed to about half of the elevated HONO concentration peaks, with the conversion rates in the range of 0.05% to 0.96%h(-1). Meanwhile, a large amount of particulate nitrite, which greatly exceeded the concentration of the gas-phase HONO, was also produced through the heterogeneous reactions of NO2. The large yields of particulate nitrite were facilitated by abundant ammonia and particulate cations in urban Ji'nan. Notably, in the daytime, particulate nitrite acted as a potential source of HONO, especially in conditions of low humidity and acidic aerosols, which possibly has subsequent effects on photochemistry in the boundary layer., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The performance of a hybrid phytosystem in landscape water purification and herbicides removal was investigated. The phytosystem operating in an arboretum is located in the Minhang Campus of Shanghai Jiao Tong University, China. The phytosystem is composed of two purification stages: sedimentation Stage 1 without external air supply; and Stage 2 with an external air supply. Stage 2 is also vegetated with three major kinds of plants, namely Pontederia cordata L., Typha latifolia L. and Cyperus alternifolius L. The system's hydraulic loading rate (HLR) was maintained at 1.632 m/day between December 2013 and November 2014. Sedimentation, filtration and adsorption by filter media, combined microbial processes in the rhizosphere (nitrification-denitrification) and plant uptake of the pollutants were all responsible for water purification in the phytosystem. The biological and physical parameters analyzed were total dissolved nitrogen (TDN), nitrate (NO3-N), nitrite (NO2-N), ammonia (NH3-N), total dissolved phosphorus (TDP), dissolved organic carbon (DOC), turbidity, chlorophyll-a and algal cells number. Highest removal efficiencies for TDN, TDP, turbidity, DOC, chlorophyll-a and algal cells were 56.9%, 73.3%, 92.4%, 29.9%, 94.3% and 91.0%, respectively. When the phytosystem was considered for herbicides removal, removal efficiencies of more than 25% were noted for all the herbicides.

The coastal wetland, a key transitional zone between land and ocean, is a complex and sensitive ecosystem with special environmental processes and functional values. Sediment and sea water samples were taken from Chongming east intertidal flat, a typical coastal wetland in China. Sediment cores were incubated under simulated spring tides (approximately twice a month) and semi-diurnal tides (two almost equal high tides and two low tides in a lunar day), to define the responses of nitrogen to periodic alternation of drying and re-flooding. The contents of NO3(-) -N, NO2(-) -N, NH4(+) -N, dissolved organic N (DON), and the activities of nitrate reductase (Nar), nitrite reductase (Nir), and hydroxylamine reductase (Hyr) in sediments were determined during the incubation. Nitrification stood in a dominant position during the drying period with sediment moisture decreasing from 35% to 5% -7% in simulated spring tides. The NO3(-) -N and NO2(-) -N were found to be substantially converted into DON following a further exsiccation (the sediment moisture decreased from 5%-7% to 0%-3%). However, the conversion rates decreased with the increase of drying and rewetting cycles. Following the rewetting of dried sediments (from 0% -3% to 37% -45%), the contents of NO3(-) -N, NO2(-) -N, NH4(+) -N and DON increased to 1 to 3 times that of the dry sediments. Nar and Nir activities in sediments rapidly increased after the rewetting, indicating that the reduction of NO3(-) -N and NO2(-) -N were substantially enhanced. Significant positive correlations were found between Nar and Nir activities, and Hyr activities and NH4(+) -N contents during the simulated spring tides. Moreover, the decreases of NO3(-) -N and NO2(-) -N contents were observed to be significantly correlated to the increases of NH4(+) -N contents. Combined with the fact that the sediment had a high organic carbon content but a very low NO3(-) -N content, it can be concluded that the reduction of NO3(-) -N and NO2(-) -N following the rewetting was dominated by nitrate ammonification. In contrast, NO3(-) -N, NO2(-) -N, NH4(+) -N and DON contents in sediments were relatively stable during semi-diurnal tides, which were (3.0 +/- 0.3), (1.2 +/- 0.1), (133.3 +/- 4.3) and (41.1 +/- 10.6) mg x kg(-1), respectively. This indicated that semi-diurnal tides slightly affected the variations of nitrogen contents in the wetlands.

A new instrument for measuring atmospheric nitrous acid (HONO) was developed, consisting of a double-wall glass stripping coil sampler coupled with ion chromatography (SC-IC). SC-IC is featured by small size (50 x 35 x 25 cm) and modular construction, including three independent parts: the sampling unit, the transfer and supporting unit, and the detection unit. High collection efficiency (> 99%) was achieved with 25 micromol/L Na2CO3 as absorption solution even in the presence of highly acidic compounds. This instrument has a detection limit of 8 pptv at 15 min time resolution, with a measurement uncertainty of 7%. Potential interferences from NO(x), NO2+SO2, NO2+VOCs, HONO+O3, HNO3, peroxyacetyl nitrite (PAN) and particle nitrite were quantified in laboratory studies and were found to be insignificant under typical atmospheric conditions. Within the framework of the 3C-STAR project, inter-comparison between the SC-IC and LOPAP (long path liquid absorption photometer) was conducted at a rural site in the Pearl River Delta. Good agreement was achieved between the two instruments over three weeks. Both instruments determined a clear diurnal profile of ambient HONO concentrations from 0.1 to 2.5 ppbv. However, deviations were found for low ambient HONO concentrations (i.e. < 0.3 ppbv), which cannot be explained by previous investigated interference species. To accurately determine the HONO budget under illuminated conditions, more intercomparison of HONO measurement techniques is still needed in future studies, especially at low HONO concentrations.

Drawing lessons from the clean development mechanism (CDM), this paper developed a combined margin methodology to quantify baseline emission factors of air pollutants in China's regional power grids. The simple average of baseline emission factors of SO2, NOX, and PM2.5 in China's six power grids in 2010 were respectively 1.91 kg/MWh, 1.83 kg/MWh and 0.32 kg/MWh. Several low-efficient mitigation technologies, such as low nitrogen oxide burner (LNB), were suggested to be replaced or used together with other technologies in order to virtually decrease the grid's emission factor. The synergies between GHG and air pollution mitigation in China's power sector was also notable. It is estimated that in 2010, that every 1% CO2 reduction in China's power generation sector resulted in the respective coreduction of 1.1%, 0.5%, and 0.8% of SO2, NOX, and PM2.5. Wind is the best technology to achieve the largest amount of coabatement in most parts of China. This methodology is recommended to be used in making comprehensive air pollution control strategies and in cobenefits analysis in future CDM approval processes.

Electric vehicles (EVs) and compressed natural gas vehicles (CNGVs), which are mainly coal-based and natural gas-based, are the two most widely proposed replacements of gasoline internal combustion engine vehicles (ICEVs) in P.R. China. We examine fuel-cycle emissions of greenhouse gases (GHGs), PM(2.5), PM(10), NO(x), and SO(2) of CNGVs and EVs relative to gasoline ICEVs and hybrids, by Chinese province. CNGVs can currently reduce emissions of GHGs, PM(10), PM(2,5), NO(x), and SO(2) by approximately 6%, 7%, 20%, 18% and 22%, respectively. EVs can reduce GHG emissions by 20%, but increase PM(10), PM(2.5), NO(x), and SO(2) emissions by approximately 360%, 250%, 120%, and 370%, respectively. Nevertheless, results vary significantly by province. Regarding their contribution to national emissions, PM increases from EVs are unimportant, because light-duty passenger vehicles contribute very little to overall PM emissions nationwide (≤0.05%); however, their NO(x) and SO(2) increases are important. Since China is striving to reduce power plant emissions, EVs are expected to have equivalent or even lower SO(2) and NO(x) emissions relative to ICEVs in the future (2030). Before then, however, EVs should be developed according to the cleanness of regional power mixes. This would lower their SO(2) and NO(x) emissions and earn more GHG reduction credits.

Nitrate and nitrite levels in six types of beverages--total of 292 individual samples from 73 brands (four bottles each)--from Guangzhou city in China were evaluated by ion-pair high-performance liquid chromatography. All samples contained nitrate. Nitrate and nitrite ranges were 0.43-46.08 and <0.005-0.501 mg/L, respectively. The highest nitrate levels were detected in tea drinks (46.08 mg/L). For nitrite, the highest levels were found in fruit juice drinks (0.501 mg/L). Three brands of fruit juice drinks exceeded the Joint FAO/WHO Expert Committee on Food Additives provisional guideline value of 0.2 mg/L for nitrite and were considered to be hazardous for public health. This study supplies useful information on safety of Chinese bottled beverages.

A simple gold plate electrode (GPE) based on a gadolinium-doped titanium dioxide (Gd/TiO₂) ultrathin film was successfully constructed by using a surface sol-gel technique, and used for the detection of trace amounts of nitrite in cured foods. The Gd/TiO₂ nanoparticles were synthesised and characterised via scanning electron microscopy (SEM) and X-ray diffraction (XRD), indicating that the Gd-doped TiO₂ formed an anatase phase through roasting at 450°C, generating actively interstitial oxygen at the interface of the surface of TiO₂ lattice surrounded by Gd³⁺. The electro-catalytic effect for oxidation of nitrite on the modified electrode was investigated by cyclic voltammetry in 0.10 mol l⁻¹ sulfuric acid media solution, showing that the modified electrode exhibited excellent response performance to nitrite with good reproducibility, selectivity and stability. The catalytic peak current was found to be linear with nitrite concentrations in the range of 8.0 × 10⁻⁷ to 4.0 × 10⁻⁴) mol l⁻¹, with a detection limit of 5.0 × 10⁻⁷ mol l⁻¹ (S/N = 3). The modified electrode could be used for the determination of nitrite in the cured sausage samples with a satisfactory recovery in the range of 95.5-104%, showing its promising application for food safety monitoring.

The real-world fuel efficiency and exhaust emission profiles of CO, HC and NOx for light-duty diesel vehicles were investigated. Using a portable emissions measurement system, 16 diesel taxies were tested on different roads in Macao and the data were normalized with the vehicle specific power bin method. The 11 Toyota Corolla diesel taxies have very good fuel economy of (5.9 +/- 0.6) L/100 km, while other five diesel taxies showed relatively high values at (8.5 +/- 1.7) L/100 km due to the variation in transmission systems and emission control strategies. Compared to similar Corolla gasoline models, the diesel cars confirmed an advantage of ca. 20% higher fuel efficiency. HC and CO emissions of all the 16 taxies are quite low, with the average at (0.05 +/- 0.02) g/km and (0.38 +/- 0.15) g/km, respectively. The average NOx emission factor of the 11 Corolla taxies is (0.56 +/- 0.17) g/km, about three times higher than their gasoline counterparts. Two of the three Hyundai Sonata taxies, configured with exhaust gas recirculation (EGR) + diesel oxidation catalyst (DOC) emission control strategies, indicated significantly higher NO2 emissions and NO2/NOx ratios than other diesel taxies and consequently trigger a concern of possibly adverse impacts on ozone pollution in urban areas with this technology combination. A clear and similar pattern for fuel consumption and for each of the three gaseous pollutant emissions with various road conditions was identified. To save energy and mitigate CO2 emissions as well as other gaseous pollutant emissions in urban area, traffic planning also needs improvement.

Methane (CH(4)) emissions from a full-scale anaerobic/anoxic/oxic (A/A/O) wastewater treatment plant (WWTP) (Jinan, China) were investigated during spring and summer of 2010. Results showed that the major emission sources of CH(4) performed the following descending order: anaerobic tanks, oxic tanks, aerated grit chambers and sludge concentration tanks. The total annual fluxes of CH(4) emissions from the Jinan WWTP were 1.69 × 10(4)kg yr(-1), with the emission factors of per capita emissions of 11.3g CH(4) person(-1)yr(-1) and flow-based emissions of 1.55 × 10(-4)g CH(4) (L of wastewater)(-1). The estimated source strength of methane for all WWTPs in China was 6.2 Gg yr(-1) (1 Gg=10(9)g). The most significant factors influencing methane emissions were dissolved oxygen concentration in aerated grit chamber and oxic tank and water temperature in high density settler tanks., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

33 total suspended particle samples and 7 size-segregated particle samples were collected over the East China Sea from Nov. to Dec., 2006, Feb. to Mar., 2007 and May. to Jun., 2008. Concentrations of ammonium, nitrate and nitrite in aerosols were measured to investigate their seasonal variation and size distribution. The concentrations of ammonium in aerosols ranged from 2.6 to 646.9 nmol x m(-3) ,with the higher values observed in winter and spring, and the lower values in summer. Nitrate concentrations were from 5.5 to 281.5 nmol x m(-3), presenting the seasonal trend of winter > spring approximately summer. The concentrations of nitrite were very low, less than 0.5 nmol x m(-3). The relative contributions of nitrogen species to total nitrogen varied seasonally in some extent. The contribution of nitrate was comparable with that of ammonium in winter, while the contribution of ammonium was the predominant in spring and summer. The size distribution of nitrate presented clear monthly changes. Most of nitrate existed in the fine particles less than 2.1 microm in Nov. to Dec., and it predominated in the coarse particles with the size of 1.1-4.7 microm and 2.1-7.0 microm, respectively, in Feb. to Mar. and May. to Jun. The size distributions of ammonium in different months were similar, with one peak presenting in the < 1.1 microm fine particles. The air mass back trajectories analysis indicated that the distributions of inorganic nitrogen in aerosols were significantly influenced by the sources and transport pathways of air mass. Both high nitrogen concentration per unit atmospheric volume (nmol x m(-3)) and per unit mass particle (micromol x g(-1)) occurred when the air mass passed over severe pollution region. Both low concentration in atmosphere and particle occurred when the air mass came from clean marine atmosphere. Lower concentration in atmosphere and higher concentration in particle occurred when the air mass originated from the continent and transported long distances over the sea.

Biogenic amines in 42 traditional Chinese sausage samples obtained from different regions were determined by HPLC. The result showed that cadaverine was the major amine, followed by tyramine and putrescine. A total of 4 groups of samples were identified on the basis of total amines by cluster analysis. Group A included samples showing low amine contents (76.5 to 220 mg/kg) and accounted for 28.5% of the sausages examined. Group B included samples with moderate amine contents (220 to 600 mg/kg) and accounted for 45.2%. Group C included 11.9% of the samples showing high total biogenic amines contents (600 to 1000 mg/kg) and group D contained 14.28% of the samples showing very high levels of biogenic amines (higher than 1000 mg/kg). High correlation coefficients were found between the total counts of Enterobacteria and concentrations of total biogenic amines (r = 0.73). Sanitary quality of raw materials and the specific flora are import factors influencing biogenic amines formation in traditional Chinese sausages. Practical Application: Biogenic amines are considered potentially harmful substances to human health worldwide and are usually found in fermented sausage.Traditional Chinese sausage is one form of spontaneously fermented sausage and manufactured in small-scale plants following spontaneous fermentation. Little information, however, exists on the traditional Chinese sausage.

Limited filamentous bulking caused by low dissolved oxygen (DO) was proposed to establish a low energy consumption wastewater treatment system. This method for energy saving was derived from two full-scale field observations, which showed pollutants removal would be enhanced and energy consumption could be reduced by at least 10% using limited filamentous bulking. Furthermore, preliminary investigation including the abundance evaluation and the identification of filamentous bacteria demonstrated that the limited filamentous bulking could be repeated steadily in a lab-scale anoxic-oxic reactor fed with domestic wastewater. The sludge loss did not occur in the secondary clarifier, while COD and total nitrogen removal efficiencies were improved by controlling DO for optimal filamentous bacterial population. Suspended solids in effluent were negligible and turbidity was lower than 2 NTU, which were distinctly lower than those under no bulking. Theoretical and experimental results indicated the aeration consumption could be saved by the application of limited filamentous bulking.

This study reports a survey of nitrite in a variety of foods consumed in north-east China and estimates the intake of nitrite for the north-east Chinese consumer. A total of 642 food categories including rice and rice products, flour and flour products, soybean and products, vegetables, fruit, preserved vegetables, cured meat products, dairy products, fish products, salt, and soy sauce were analysed for their content of nitrite. Nitrite content was quite different both between different food categories and within the same food category, ranging from not determined (n.d.) to 19.7 mg kg(-1). A great variation in the content of nitrite was found for all the food products. The average content of nitrite was highest in cured meat products (14.3 mg kg(-1)). Next to that, the nitrite content was high in the order of preserved vegetables (4.1 mg kg(-1)), soybean products (3.5 mg kg(-1)), and dairy products (1.9 mg kg(-1)). The lowest average values of nitrite were detected in soy sauce, rice and rice products, salt and fish products, the contents being 0.1, 0.3, 0.3, and 0.6 mg kg(-1). Calculations on the basis of these results and including dietary surveys show that the average intake of nitrite in north-east China from food was 0.03 mg kg(-1) body weight for an average Chinese person weighing 60 kg, and the data are lower than the established acceptable daily intake (ADI) for nitrite. Cured meat products are normally the major contributor to average nitrite intake of the north-east Chinese population. The second contributor is vegetables.

The combined partial nitrification/Anammox process is especially suitable for the treatment of influents with low C/N ratio. However, many nitrogenous wastewater are also rich in organics. Two systems (continuous stirred-tank reactor (CSTR) and sequencing batch reactor (SBR)) are commonly used to achieve nitrite accumulation, but no complete comparison between these two systems for treating different wastewater has been reported. The objective of this paper was to compare the partial nitrification in CSTR and SBR for the treatment of ammonium-rich organic wastewater. The result showed that it took a shorter time to startup partial nitrification in CSTR, but SBR was a better option for treating ammonium-rich organic wastewater with C/N lower than 0.34. With increase HRT to 48 h, excellent nitrite accumulation could be achieved in both reactors for wastewater containing landfill leachate. For subsequent anammox, CSTR was more suitable when leachate percentage ranged from 35% to 40%.

Most studies related to nitrogen flux across the sediment-water interface were focused on the effects of aquatic environment factors on nitrification rates, while there is no information about the effects of nitrification on other factors. In this research, laboratory experiments have been conducted to investigate nitrogen flux from the sediment cores collected from the Three-Gorge Reservoir of the Yangtze River (China). The effects of the nitrification process on the fluxes of ammonium (NH4+), nitrite (NO2-) + nitrate (NO3-), and total organic nitrogen (TON) across the sediment-water interface have been examined. The release flux of TON accounted for more than 50% of the total nitrogen. The nitrification process stimulated the growth of ammonifying bacteria and accelerated the release of NH4+ and NOx- from the sediment cores during the 40-day incubation and TON during the first 10-day incubation. A 25% increase in the nitrification rate increased the release rates of NH4+ and TON by approximately two times during the first 8-day incubation.

Observation of nighttime nitrate radical (NO3) was performed by using long path differential optical absorption spectroscopy (LP-DOAS), on the outskirts of Hefei, China. The time series of NO3 and supporting parameters were simultaneously measured for a week (31 May-7 June 2006). The results indicated that the average concentration of NO3 was 15.6 pptv with an average lifetimes of 96 s, whereas, NO3 production rates varied from 8 x 10(5)/(cm3 x s) to 2.98 x 10(7)/(cm3 x s). Furthermore, the calculated N2O5 concentration averaged at 380 pptv. Analysis of data indicated that direct sinks were probably dominating the NO3 loss process during this campaign. The results were compared with other campaigns in the boundary layer.

Vertical and temporal distributions of N and P in soil solution in aquatic-terrestrial ecotone (ATE) of Taihu Lake were investigated, and the relations among N, P, ORP (oxidation reduction potential), TOC, root system biomass and microorganism were studied. As a whole, significant declines in TN, NO3- -N, DON (dissolved organic nitrogen) and TP concentration in soil solution have occurred with increase of the depth, and reached their minima at 60 cm depth, except for NH4+ -N, which increased with depth. The concentration of TP increased gradually from spring to winter in the topsoil, the maximum 0.08 mg/L presented in the winter while the minimum 0.03 mg/L in spring. In the deeper layer, the concentration value of TP fluctuated little. As for the NO3- -N, its seasonal variation was significant at 20 cm depth, its concentration increased gradually from spring to autumn, and decreased markedly in winter. Vertical and temporal distribution of DON is contrary to that of NO3- -N. The results also show that the variation of N and P in the percolate between adjacent layers is obviously different. The vertical variation of TN, TP, NO3- -N, NH4+ -N and DON is significant, of which the variation coefficient of NO3- -N along the depth reaches 100.23%, the highest; while the variation coefficient of DON is 41.14%, the smallest. The results of correlation analysis show that the concentration of nitrogen and phosphorus correlate significantly with TOC, ORP, root biomass and counts of nitrifying bacteria. Most nutrients altered much from 20 to 40 cm along the depth. However, DON changed more between 60 and 80 cm. Results show that soil of 0-60 cm depth is active rhizoplane, with strong capability to remove the nitrogen and phosphorus in ATE. It may suggest that there exists the optimum ecological efficiency in the depth of above 60 cm in reed wetland. This will be very significant for ecological restoration and reestablishment.

Objective: To understand the nitrate and nitrite contents of drinking water in Shanxi Province, China., Methods: Water samples were collected from Pingding and Taigu counties and Taiyuan City. The nitrate and nitrite contents were determined following the 'Drinking water hygienic standard-2001'., Results: The median nitrate content of drinking water was 3.5 mg/L, and the proportion of samples above national hygienic standard for drinking water was 4.0% in study areas. The median nitrite content of well water samples(5.l mg/L) was higher than that of tape water (2.7 mg/L). The median content of nitrite was 0.004 mg/L for all samples, and the median content of spring water was highest (0.017 mg/L) than that of other sources. Conclusion The contents of nitrate and nitrite in drinking water were similar to that reported form other regions. Maternal nitrate exposure from drinking water may not be among the important risk factors of high prevalence of birth defects in Shanxi Province.

Six new sesquiterpene coumarin derivatives, 2,3-dihydro-7-hydroxy-2R,3R-dimethyl-2-[4,8-dimethyl-3(E),7-nonadien-6-onyl]furo[3,2-c]coumarin (4), fukanefuromarin A (5), fukanefuromarin B (6), fukanefuromarin C (7), fukanefuromarin D (8), and fukanemarin A (9), were isolated from a 80% aqueous methanol extract of the roots of Ferula fukanensis. The structures were elucidated on the basis of spectral evidence, especially heteronuclear multiple-bond connectivity (HMBC), nuclear Overhauser exchange spectroscopy (NOESY), and high-resolution MS. An extract of F. fukanensis (FFE) and the sesquiterpene coumarin derivatives inhibited nitric oxide (NO) production and inducible NO synthase (iNOS) gene expression by a murine macrophage-like cell line (RAW 264.7), which was activated by lipopolysaccharide (LPS) and recombinant mouse interferon-gamma (IFN-gamma).

The contents of nitrate and nitrite in potato, cabbage, Chinese cabbage, scallion (shallot), celery, cucumber, tomato, eggplant and wax gourd taken from the north China market from 1998 to 1999 were determined. These vegetables provide the major contribution to the nitrate intake from the diet. The highest content of nitrate was found in celery followed by Chinese cabbage, cabbage, scallion, wax gourd and eggplant. For all the products, a great variation in the content of nitrate was found. Generally, the nitrite content was low. The average intake of nitrate and nitrite from these vegetables was estimated as approximately 422.8 and 0.68 mg day(-1), respectively.

Nitrogen contamination is one of the most serious problems in the Yellow River of China. This study was conducted to analyze monitoring data on nitrogen contamination for the Yellow River basin in the years 1980, 1990, 1997, and 1999. Several significant results have arisen from the study. First, in conjunction with an increase in economic indexes from the Yellow River's upper basin to its lower basin, the nitrogen concentration in the tributaries also showed an increasing trend from the upper to the lower basin, which, in turn, led to an increase in the nitrogen concentration of the mainstream from the upper to the lower reaches. Second, nitrogen in the river water in the mainstream and the tributaries of the Yellow River was attributed mainly to point sources. In spite of the fact that the ratio of point to nonpoint sources decreased from 2.7 in 1990 to 1.8 in 1997 for total inorganic nitrogen in river water at the Tongguan Station in the lower basin, point sources increased more than nonpoint sources. Third, the ammonium nitrogen and total inorganic nitrogen content of the river water increased significantly in the mainstream and the tributaries during the 1980-1999 period, a change caused by an increase in wastewater discharge and nitrogenous fertilizer application in the Yellow River catchment.

The data at 570 monitoring stations during 1990 were studied. The results indicate as follows: (i) the contents of nitrogen in the Yangtze mainstream has a raising trend from the upper reaches to the lower reaches; (ii) total nitrogen content at a lot of stations during the middle 1980s is 5-10 times more than that during the 1960s; (iii) seasonal variances of nitrogen content vary with watersheds; and (iv) the difference of nitrogen contamination level is related to the regional population and economic development.

Recently, epidemiologic data have indicated that the number of deaths caused by malignant tumor presented a significantly rise in Beicun countryside of Datong city. In order to understand the causes of high incidence of cancer, factors were investigated and analysed related to air, river water, drinking water, vegetables and human serum. Results showed that Benzo (a)-pyrene (Bap), total suspended particulates (TSP) in air, nitrate, nitrite in drinking water and vegetables were all significantly higher in Beicun countryside region than those in controlled countryside region, respectively (P < 0.01-P < 0.001). The micronuclei (MN) and berration nucleus (AN) rates of cultured lymphocytes were significantly higher while cpm value of unscheduled DNA synthesis (UDS) test were significantly lower than those in controlled region among residents in Beicun countryside region, respectively (P < 0.01-P < 0.001). The micronuclei, abrerration nucleus rates and cpm value of cultured lymphocytes among residents in Beicun countryside were strongly correlated with Bap, TSP, nitrite and nitrate contents in determination samples. Our results suggest that the air and water source under serious pollution may serve as an important factor causing cytogenetic damage among residents and cancer death rise in Beicun countryside.

Cancer patients show a salivary NO2- density that is twice that of healthy individuals. This indicates that endogenous NO2- is correlated with the cancer. By applying a culture medium modified by vitamin B1 or KCIO3, we have found that many bacteria in the human body (especially the bowels) can nitrify NH4+ to NO2-. NO2- can be combined with a second amine to form nitrosamine which is a carcinogen. We fed mice using G+ coccus, which can lead to a precancerous lesion and mammary carcinoma, and proved that nitrification in vivo is carcinogenic. We have tested a method to prevent cancer in 7392 workers. Patients with a salivary density of NO2- over 10 ppm for 3 consecutive days and with light symptoms were our targets for preventive treatment using antibiotics and nitrosamine destroyers. The result shows that the average cancer incidence rate in the control group is 58.4% higher than in the experimental group over 9 years. The difference between the two groups is statistically significant (x2 = 8.5, p < 0.01). This is reliable evidence that preventive treatment is effective when based on the idea that endogenous NO2- and nitrosamine are the carcinogens.

Levels of gastric juice nitrite, several urinary N-nitroso compounds, and other analytes were examined among nearly 600 residents in an area of Shandong, China, where precancerous gastric lesions are common and rates of stomach cancer are among the world's highest. Gastric juice nitrite levels were considerably higher among those with gastric juice pH values above 2.4 versus below 2.4. Nitrite was detected more often and at higher levels among persons with later stage gastric lesions, especially when gastric pH was high. Of those with intestinal metaplasia, 17.5% had detectable levels of gastric nitrite, while this analyte was detected in only 7.2% of those with less advanced lesions. Relative to those with undetectable nitrite, the odds of intestinal metaplasia increased from 1.5 (95% confidence interval = 0.6-4.1) to 4.1 (95% confidence interval = 1.8-9.3) among those with low and high nitrite concentrations, respectively. Urinary acetaldehyde and formaldehyde levels also tended to be higher among those with more advanced pathology, particularly dysplasia. However, urinary excretion levels of total N-nitroso compounds and several nitrosamino acids differed little among those with chronic atrophic gastritis and intestinal metaplasia and dysplasia, consistent with findings from recent studies in the United Kingdom, France, and Colombia. The data from this high-risk population suggest that elevated levels of gastric nitrite, especially in a high pH environment, are associated with advanced precancerous gastric lesions, although specific N-nitroso compounds were not implicated.

Epidemiological studies show that the consumption of Chinese salted fish is a causative factor for nasopharyngeal carcinoma (NPC) in southern China. In the present study, N-nitrosamines and their precursors were analyzed in 145 samples of cooked, salted fish collected from various areas in China. The results show that N-dimethylnitrosamine (NDMA), N-diethylnitrosamine (NDEA), N-nitrosopyrrolidine (NPYR) and N-nitrosopiperidine (NPIP) were present in the salted fish. Total volatile N-nitrosamines (TVN) in the salted fish were 0.028 to 4.54 mg/kg. The samples from areas with higher NPC risk showed a higher average level of TVN than those from areas of lower NPC risk. Positive correlations were found between the levels of NDMA, NDEA and TVN and mortality from NPC. Although neither the nitrates nor the nitrites in the salted fish were present at significantly high levels, in vitro data regarding nitrosation of salted fish showed that the N-nitrosamine content had increased substantially. The results support the conclusion that the high NPC risk in southern Chinese may be attributed to consumption of salted fish containing high levels of N-nitrosamines.

Quality of drinking water was comprehensively studied in Fusui County of Guangxi, a high-incidence area for liver cancer. The results indicated pond water was polluted the most severely, well water the least, and river water intermediately. The chemical indicators for water pollution were levels of ammonia, nitrite, humic acid, suspended substances, chemical oxygen demand, and biological oxygen demand. Quality of drinking water was worse in high incidence area for liver cancer than that in low-incidence one. Mortality of liver cancer correlated positively with the levels of nitrite, humic acid, chemical oxygen demand, and so on. These results provided a basis for further studies on the etiology of liver cancer.

There are conflicting reports on whether nitrate intake is related to gastric carcinogenesis. In this laboratory/field study from a high-risk area for gastric cancer, we analysed 178 samples of drinking water for nitrate and nitrite, and examined the relationship between gastric mucosal lesions (including gastric cancer) and quality of different types of drinking water and nitrate intake via water. The results showed that the nitrate content in the local drinking water was generally very high, with a mean of 109.6 mg/l (range 4.4-497.2 mg/l). There were significant differences in the nitrate content in drinking water from different wells in qualitatively different types of water. The histological changes were closely related to the quality of drinking water and its nitrate content. The results suggest that nitrate in drinking water probably plays an important role in gastric carcinogenesis and that in future aetiological studies of gastric cancer should include more information on well depth, the presence of public or private wells and nitrate content of water.

Huang Shi town in Fujian province is one of the high-risk area of stomach cancer in China with a standard mortality rate of 61.19/100,000 in males. Epidemiologic survey showed that it was related to the severe contamination of Mu-Lan river system by which the drinking water for the residents was provided. Thirty-three water samples in the summer and winter times, filtrated and unfiltrated, from different spots along this river system were collected. The concentrations of nitrite and nitrosamine were determined. NDMA, NDEA, NDPA, NDBA, NPIP and NMOR by GC-TEA and three unknown peaks preliminarily identified as non-volatile nitrosamine by LC-TEA could be detected in these samples. The kinds and the content of nitrosamine in the samples collected in the winter time were all significantly higher than those collected in the summer, P values were all less than 0.01. Its possible significance in the causes of gastrointestinal tumors is discussed.