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Abstract Hydrogel as commercial soil conditioner has the potential to improve soil properties and reduce water scarcity in growing plants. However, use of polyacrylamide-based hydrogel in agriculture pose potential human health hazards. Hydrogel systems were prepared from temperature-responsive methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC) blended with potassium sulfate (K 2 SO 4 , K-containing fertilizer). Blended K 2 SO 4 in hydrogels affects the hydrophobic interaction of MC and HPMC, and hydrogels prepared in 0.25 M K 2 SO 4 decrease the gelation temperatures of MC and HPMC from 55.6 and 67.4 °C to 27.8 and 35.1 °C, respectively. The equilibrium swelling ratio (St) of MC and HPMC hydrogels was increased 15 times and hydrogels maintained a steady appearance. The swelling kinetics of the MC and HPMC hydrogels followed Schott's second-order model and kinetic parameters indicated that adding K 2 SO 4 can improve the initial swelling rate. K 2 SO 4 decreases the pore size of the MC and HPMC hydrogel from 26.8 and 21.5 μm to 14.7 and 14.2 μm. A plant growth assessment indicated inhibition in plant growth occurred without the application of the hydrogels. Adding K 2 SO 4 increases mechanical properties of the hydrogels. Treatment with 0.5% hydrogel considerably improves the water-holding and water-retention capacities of sandy soil. The 20-20-20 fertilizer release results revealed at that at 35 °C and a pH below 7, the hydrogel systems reduce the release rate of the fertilizer. The best result was observed with the Korsmeyer–Peppas model, indicating that the fertilizer transport mechanism involves Fickian diffusion and swelling-controlled release. This study discovered that environmentally responsive cellulose-based hydrogels have potential for use as soil conditioners and as controlled release devices in horticulture and agriculture. Graphical abstract Unlabelled Image Highlights • Gel temperature of cellulose-based hydrogel can be adjusted by concentration of K 2 SO 4. • Adding K 2 SO 4 can improve the initial swelling rate and mechanical properties of hydrogels. • The hydrogels could effectively improve the water-retention capacities of sandy soil. • The hydrogels can reduce the release rate of the fertilizer. • The fertilizer release profiles reveal temperature- and pH-responsive behavior. [ABSTRACT FROM AUTHOR]

Abstract The giant panda (Ailuropoda melanoleuca) is one of the most endangered animals in the world and is recognized worldwide as a symbol for conservation. The Qinling subspecies of giant panda (Ailuropoda melanoleuca qinlingensis) is highly endangered; fewer than 350 individuals still inhabit the Qinling Mountains. Last year, China announced the establishment of the first Giant Panda National Park (GPNP) with a goal of restoring and connecting fragmented habitats; the proposal ignored the environmental pollution caused by economic development in panda habitats. The spatial distribution of heavy metals (Cd, Pb, Hg, Cu, Zn, Mn, Cr, Ni and As) was analyzed in giant panda feces, soil, bamboo, and water in four of GPNP's functional areas at different altitudes and latitudes. Heavy metal pollution decreased with anthropogenic influences, from outside the park through the buffer and into the core area. Cu, Mn, Ni and Zn accumulated from natural sources; As, Hg and Cr were associated with fuel combustion; and Pb and Cd were associated with traffic and agriculture sources. The presence of heavy metals at high altitudes and latitudes in the proposed GPNP is due to emissions from Xi'an and other upwind industrial cities. We conclude that reducing emissions and heavy metal input should be included in the design of the GPNP. Policy interventions should consider functional zones planning, wind direction, reducing mining, and the abandonment of existing roads and farmland within the GPNP to reduce other direct human impacts on the Qinling panda. Graphical abstract Unlabelled Image Highlights • Heavy metals contents increased from core, buffer to environmental areas in Qinling. • Heavy metal distribution was correlated with altitude and latitude in Qinling. • Minimizing heavy metals emission is a long-term task for panda conservation. • Expanding core area and adherence to the basic principle of functional areas • Establishing pollutants monitoring and staple bamboo protection [ABSTRACT FROM AUTHOR]

Abstract The Yellow River flows through Lanzhou city and is the only drinking water source for 3.6 million residents. Yet, little is known regarding the safety and quality of the Yellow River for resident consumption. To address this knowledge-gap, water samples were collected from different sites within this section during the dry and wet seasons. Physico-chemical parameters and microbial community metrics were analyzed to assess the health risk associated with this Chinese mother river. Water quality of the river was better during the dry season (March–April) than in the wet season (September–October). Fifteen conventional physico-chemical and biological indices, such as NH 3 -N, NO 2 −-N, total nitrate (TN), five day biochemical oxygen demand (BOD 5), chemical oxygen demand (COD), volatile phenol (VP), and coliform abundances, generally exceeded acceptable standards. The average abundance of coliforms was 2.8 times that of acceptable standards in the dry season and 4.6 times the standards in the wet season. The concentration of the toxic metal As was more than two times than that of the national standard in waters from the wet season. Microbial community analysis also indicated that community diversity and species richness were positively correlated with the concentrations of several physico-chemical parameters. The results indicate that As and Cr6+ pose potential risk for human health through consumption by residents. Further, the results indicated that human activities are the main causes of water pollution, and that long-term strict monitoring should be conducted to ensure the safety of drinking water consumption and the health of the environment. Graphical abstract Unlabelled Image Highlights • Water quality was better in the dry than that in the wet season. • As, Cr6+ and Pb have a potential risk for residents health. • Pathogenic coliform was positive with physico-chemical parameters. • The Yellow River has potential environmental risk. • Strictly environmental policy should be taken for resident health. [ABSTRACT FROM AUTHOR]

Constructed wetlands (CWs) for pesticide mitigation from agricultural runoff became widespread in the last decade. However, comparison of different types of CWs at one location is missing. Therefore, site by site comparison of three different types (subsurface flow, surface flow and floating hydroponic root mat) of CWs treating four chloroacetanilide herbicides (acetochlor, s-metolachlor, metazachlor, dimethachlor) were carried out. All three planted systems are effective in removing the four herbicides with removal efficiency > 92% after 9 days. The metabolites ethane sulfonic acids (ESA) and oxanilic acids (OA) of the four herbicides peaked at 9 days in the surface flow CWs with soil, but all the metabolites didn't peaked in the subsurface flow with gravel systems and the floating hydroponic root mat system after 21 days. All the detected metabolites account about 20% of the mother compounds. There is no noticeable metabolites accumulation in the control system (no plants and no substrate), which indicate no microbial degradation taken place. Plant accumulation and soil adsorption are negligible for the removal of the four herbicides, which are < 0.6%. In conclude, plants can enhance the removal of chloroacetanilide herbicides in all the CWs, and the floating hydroponic root mat is the most cost-efficient alternatives for chloroacetanilide herbicides removal due to the absence of substrate. [ABSTRACT FROM AUTHOR]

Rural communities in central and eastern Europe usually use constructed wetlands (CWs) to treat domestic wastewater. Effluents from these systems are regularly discharged to receiving water, resulting in a potential transfer of pharmaceuticals and personal care products (PPCPs) from sewage to the aquatic environment. In this study, the seasonal occurrence, removal and risk assessment of 32 multi-class PPCPs were investigated in three CWs from the village of south Bohemia, Czech Republic. Among the PPCPs considered, 25 compounds were detected in sewage influent, and ibuprofen, caffeine and paracetamol were the most commonly detected PPCPs. The removal efficiencies of PPCPs in the rural CWs exhibited large variability with 11–100% for anti-inflammatories, 37–99% for β-blockers and 18–95% for diuretics. The statistical results revealed significant correlations between removal efficiencies of six PPCPs and conventional water quality parameters. The ecotoxicological assessment study revealed that most of the PPCPs (except ibuprofen) in the effluent yielded low aquatic risk. This study suggested that constructed wetlands could be effective for removing PPCPs and reducing environmental risk of PPCPs discharged from rural communities into surface water systems. [ABSTRACT FROM AUTHOR]

Given the widely varying types of aquatic ecosystems and bioavailability of chemicals, it is important to develop site-specific water quality criteria (WQC) to ensure criteria are neither over- nor under-protective. In the study, using pentachlorophenol (PCP) as an example, several approaches to derive site-specific WQC were investigated, including the conventional species sensitivity distribution (SSD), weighted SSD based on the proportion of each trophic level, and water effect ratio (WER) method. When corrected to a pH of 7.8, the conventional SSD approach resulted in criteria maximum concentration (CMC) and criteria continuous concentration (CCC) of 18.11 and 1.74 μg/L, respectively. If SSD was weighted according to the current species composition in Tai Lake, the CMC and CCC were 32.81 and 4.48 μg/L, respectively. However, available data suggest that many sensitive species inhabiting Tai Lake during 1980s were disappeared. Considering the species composition of the healthier ecosystem in 1980s, the CMC and CCC were 10.99 and 0.38 μg/L, respectively, which provide more protective water quality standards. Water effect ratio (WER) was further used to correct for co-occurrence of other toxicants and factors affecting bioavailability of PCP. A final WER of 4.72 was applied to adjust the criteria derived by using the weighted SSD for the 1980s aquatic community, and the final CMC and CCC obtained were 51.87 and 1.79 μg/L, respectively, at a pH of 7.8. Water quality criteria derived using the 1980s species composition and adjusted with WER were deemed the most appropriate WQC for water management and aquatic life protection. Merits of the various approaches for developing WQC for protection of aquatic species were discussed. [ABSTRACT FROM AUTHOR]

Heavy metals (HM) are ubiquitous in environments, and HM pollution has become a severe global crisis. Previous studies have identified HM levels in Qinling panda habitats but their levels and the associated risks in Sichuan panda habitats are still unknown. Risk-based conservation management is in urgent need and should rely upon identifying risk distributions, quantified risk-source apportionment and collaborative governance. We carried out research in Sichuan panda (Ailuropoda melanoleuca melanoleuca) habitats taking soil, bamboo, and water samples from three different areas (nature reserves, potential habitats, and surrounding regions) of five mountains. The concentrations of HM in the soil were higher than those in bamboo, but both exceeded the background or national standards to varying degrees, suggesting long-term pollution and multi-element contamination. Regional and geographical distribution differences revealed a positive correlation between intensity of human activities and HM pollution. HM contaminants observed in the Sichuan panda habitats, based on their sources, were categorized into coal combustion (34%), industry (44%), and traffic (22%). In particular, our results showed the northern and southern parts of habitat were of highest concern, as they had environmental conditions that could be harmful to the health of giant pandas. Coupling models applying positive matrix factorization model/risk were used to quantify source contributions to various risk types, which was based on real-time monitoring and served as a positive role in multi-step process for developing countermeasures, with the goal of collaboratively reframing the vision and governance of panda conservation in order to incorporate regional disparities. Unlabelled Image • The level and risks of heavy metals in Sichuan panda habitat were investigated. • Heavy metal concentrations in soil were higher than those in bamboo. • Northern and southern parts of Sichuan habitat were of highest risk concern. • New coupling models improved the sources traceability of regional risks. • Proposed a policy-making process to reduce risks and regional disparities. [ABSTRACT FROM AUTHOR]

Terrestrial water storage (TWS) has a major impact on the water, energy, and biogeochemical fluxes of the land surface. The spatiotemporal features of TWS variations, as well as the roles of climate change and human activities in TWS variations, have been of key concerns and need to be further investigated. Here, using the data products from the Gravity Recovery and Climate Experiment and the Global Land Data Assimilation System, together with some auxiliary data on climate, evapotranspiration, and vegetation leaf area index (LAI), we investigated the spatiotemporal variations of global TWS and how TWS was partitioned into its different components. We further quantified the sensitivity of TWS to changes in climate and vegetation LAI, as well as the impacts of climate and vegetation LAI changes on TWS during 2002–2016. The results showed that global TWS declined at a rate of 0.04 mm month−1 during 2002–2016 with a spatially explicit pattern and a distinct seasonal pattern, although the trend was negligible before October 2009 and only became obvious after that. With the seasonal variations of precipitation, temperature, and LAI together, the seasonal variations of TWS were able to be explained by ≥50% in the tropical and subtropical regions. With the joint changes in LAI, temperature, and precipitation, TWS increased by ≤ ~10 mm month−1 in the subarctic and inland temperate regions, and some tropical and subtropical regions; by contrast declined by ≤ ~10 mm month−1 in some regions such as the Central Africa. Our study shed light on the spatiotemporal characteristic of the TWS variations and quantified the impacts of climate and vegetation LAI changes on TWS. The findings can provide not only important evidence for the effectiveness of past ecosystem management intervention programs in water retention service but also guidance for planning ecosystem management intervention programs in the near future. [ABSTRACT FROM AUTHOR]

Novel hierarchically structured Faujasite Type (FAU) zeolite was fabricated from industrial waste lithium silica fume (LSF) via hydrothermal method without the addition of templates. The FAU zeolites exhibited spherical filler morphology with maximum surface area of 372.8 m2/g, enriched microporosity (0.164 cm3/g), and abundant mesoporosity. Owing to its unique structure, the FAU zeolite allowed ultrafast diffusion and rapid trap of copper ion inside the cages of zeolite crystals, and achieved maximum removal (78.76%) of Cu(II) within the very first 2 min, with adsorption rate constant 5.46–6.27 times greater than that of mesoporous commercial zeolite (CZ) between 15 and 45 °C. The physico-chemical structures of the FAU zeolites were carefully studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier Transform Infrared Spectrometry (FT-IR), surface area analyzer (BET) and X-ray photoelectron spectroscopy (XPS). The maximum q e toward Cu(II) achieved by FAU zeolite (i.e., Z9, S/A of 9) featuring a q e of 94.46 mg/g at 25 °C as per calculated from Langmuir model, which is more than twice amount achieved by CZ (39.15 mg/g). Z9 also showed outstanding selectivity for Cu(II) over various coexisting ions. The saturated Z9 can be regenerated with a mild washing procedure, and the spent zeolite can be reused as effective antibacterial agent. This work proposes a cost-effective and green synthesis route for the hierarchically structured zeolite with high copper selective removal capacity from industrial waste. Unlabelled Image • Hierarchically structured FAU zeolite was produced from industrial waste LSF. • The unique structure allows extremely fast diffusion and rapid trap of Cu2+. • The spent zeolite showed excellent regeneration and antibacterial activity. • The zeolite showed outstanding selectivity for Cu(II) over various coexisting ions. [ABSTRACT FROM AUTHOR]

Modification of enzyme/protein conformation will affect the activities and functionality of enzymes. Previous studies have shown that the activity of lysozyme (LSZ) in the presence of humic acid (HA) is largely determined by the mass ratio of HA/LSZ (f = m HA/ m LSZ), pH and ionic strength. Here the interaction and conformation of LSZ in HA/LSZ-complex/aggregate (HA/LSZ-c/a) were investigated by spectroscopic techniques at (initial) pH 5 and 8 and ionic strength 5 mmol/L. The results indicated a strong interaction between HA and LSZ. Circular dichroism (CD), and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy showed that the helix content reached a minimum at the mass ratio of its iso electric point (IEP) at given initial pH, f IEP,pHi. The changes in β-sheet and random coil of HA/LSZ-c/a were opposite with increasing f. The minimum of helix content at f IEP,pHi corresponded with the minimum LSZ activity and maximum aggregate size of HA/LSZ-c/a. UV–vis spectra and fluorescence measurements indicated that the amino acid residues (especially for tyrosine) in LSZ were in a more hydrophobic microenvironment before f IEP,pHi due to the formation of HA/LSZ-c/a, while were gradually exposed to a more polar microenvironment beyond f IEP,pHi with the disaggregation of HA/LSZ-c/a. HA and LSZ interaction caused a more hydrophobic microenvironment for the amino acid residues at initial pH 8. This study improves our understanding of enzyme/protein behavior in the natural environment. Unlabelled Image • Conformation of lysozyme(LSZ) bound with HA depends on the mass ratio f HA/LSZ and pH. • LSZ conformation was closely related to its encapsulated degree and complexation size. • Helix in LSZ reached the minimum around f IEP , opposite to β-sheet and random coils. • Amino acid residues in LSZ were in a more hydrophobic micro-environment before f IEP. [ABSTRACT FROM AUTHOR]

There is a dearth of research on the hourly risk of ambulance dispatches with respect to ambient conditions. We evaluated hourly relative risks (RR) and 95% confidence interval (CI) of ambulance dispatches in Taiwan to treat respiratory distress, coma and unconsciousness, and out-of-hospital cardiac arrest (OHCA), from 2006 to 2015. We considered island-wide ambient temperatures, fine particulate matter (PM 2.5), and ozone (O 3) at lag 0–180 h while using a distributed lag nonlinear model and meta-analysis. Results showed the pooled risks peaked at lag 16–18 h for all ambulance dispatches at 99th percentile of hourly temperature (32 °C, versus reference temperature of 25 °C), with significant excess risk of 0.11% (95% CI; 0.06, 0.17) for coma and unconsciousness, and 0.06% (95% CI; 0.01, 0.11) for OHCA. The risks of exposure to 90th percentile of hourly O 3 of 52.3 ppb relative to the Q1 level of 17.3 ppb peaked at lag 14 h, with excess risk of 0.17% (95% CI; 0.11, 0.23) for respiratory distress, 0.11% (95% CI; 0.06, 0.16) for coma and unconsciousness, and 0.07% (95% CI; 0.01, 0.14) for OHCA. The population exposed to reference temperatures of 28 °C, 20 °C, and 26 °C were exposed to the lowest levels of ambulance dispatches risk for respiratory distress, coma and unconsciousness, and OHCA, respectively; the highest cumulative 0–96 h RRs of ambulance dispatches were 1.27 (95% CI; 1.19, 1.35) for OHCA at 5th percentile temperatures and 1.25 (95% CI; 1.11, 1.41) for OHCA at 99th percentile temperatures. Following an accumulating lag of 0–96 h, no significant risk was identified for hourly levels of PM 2.5 and O 3. In conclusion, the analytical results of hourly data speak to immediate and real-time responses to environmental changes, rather than to short-term relationships. In our analyses, we emphasized health events in extreme heat; thus, we recommend a comparative study of daily versus hourly associations. Unlabelled Image • Hourly 10-year data on ambulance dispatches and on ambient environment are available simultaneously for subtropical island. • The ambulance call risk associated with pollutants could be indirect associations with the temperature. • The daily and hourly acute health responses to ambient environment changes should be compared. • Findings provide public health sectors to consider more actions to response to extreme environmental conditions. [ABSTRACT FROM AUTHOR]

Understanding the effects of environmental factors on birth outcomes is crucial for public health because newborns' birth size affects their likelihood of childhood survival, risk of perinatal morbidity, and subsequent health and growth. Therefore, we investigated the associations of birth outcomes with prenatal air pollutant exposure and residential land use characteristics in the Greater Taipei Area. Participants were selected from the Longitudinal Examination across Prenatal and Postpartum Health in Taiwan study, which is an ongoing prospective study launched in July 2011. Parental sociodemographic data and medical histories were collected using standardized questionnaires. Mean air pollutant levels during each trimester were estimated using the spatial interpolation technique (Ordinary Kriging). Land use types surrounding participants' homes were evaluated within a designated radius of their residential addresses. We used multiple regressions to examine relationships between birth outcomes (i.e., birth weight, height, and head circumference) and environmental factors after adjustment for parental characteristics. A total of 436 pregnant women–infant pairs were included. Birth weight was negatively associated with commercial land and greenhouse areas near the residence. Living near greenhouse areas negatively affected birth height, but higher greenness level within 100 m of the residence had a positive effect. Birth head circumference was only associated with sociodemographic factors in the multivariate model. Land use types near the homes of pregnant women, but not exposure to air pollutants, were significantly associated with birth weight and height in the Greater Taipei Area. Increased greenness level was positively associated with birth height, and living near commercial or greenhouse areas had adverse effects on birth outcomes. Living in a healthy neighborhood is critical for the birth outcomes of infants and presumably their health in early childhood. Unlabelled Image • Increased greenness surrounding homes was positively associated with birth height. • Living near commercial land and greenhouse negatively affected birth outcomes. • High monthly household income had a protective effect on birth outcome. • Living in a healthy neighborhood is beneficial to birth outcomes. [ABSTRACT FROM AUTHOR]

To determine the water quality status of the primary tributaries in middle and lower reaches of the Yellow River Basin, water collected from the confluence of the ten tributaries and some physical, chemical and biological parameters were analyzed, and then water quality index and health risk were evaluated. Of the ten main tributaries in the middle and lower reaches, only the Qingshui River had water of medium quality in the upper reaches, while all the other tributaries contributed water of poor quality. The Jindi and Dawen rivers in the lower reaches had the poorest water quality, especially the Jindi River. TP, TN, BOD 5 , COD, TOC and coliform bacteria exceeded the national criteria by 155%, 1%, 97.5%, 35.5%, 114.2%, and 80%, respectively. Cluster analysis indicated that industrial, agricultural, and domestic sewage, along with industrial waste gas, were the main sources of pollution in these tributaries. An analysis of the bacterial community structure showed that the Jindi River was the most polluted and had the largest species diversity and richness of bacteria. Also, its number of pathogenic microorganisms was much higher than that of other areas, and the bacterial functional genes of related metabolic pathways were significantly enriched. This was in sharp contrast with that of the Qingshui River, which had the best water quality. We suggest more specifics policy should be taken for different tributaries, and poor water quality of Jindi and Dawen River should be further studied to explore the most suitable pollution control methods. Unlabelled Image • Ten tributaries had different pollution characters in the Yellow River Basin (YRB). • Water quality in tributaries deteriorated from upstream to downstream in the YRB. • Pollution sources were mainly from industrial, agricultural, and other activities. • Pollutants stimulate the reproduction of some downstream pathogenic microorganisms. • Different tributaries need unique strategies based on the nature of local pollutants. [ABSTRACT FROM AUTHOR]

Abstract Exposure to phthalate esters (PAEs) poses health risks to humans. Much research has been performed evaluating PAE levels in foodstuffs, river sediment and drinking water, but little attention has been paid to their presence in urban outdoor environments where human activities are highly intense. Here we evaluated PAE presence and distribution in street dust in Kaohsiung, the most industrialized city in Taiwan. Our results showed that PAEs were ubiquitous in fifty-two street-dust samples (levels of total PAEs 5.4–989.2 mg kg−1). Di-(2-ethylhexyl) phthalate was the most abundant congener observed and made up 85.0%, 79.7%, and 97.2% of the total PAEs found in industrial, residential and commercial areas, respectively. PAE levels in street dust in commercial areas (night markets) were significantly higher, suggesting a higher risk of contamination on people present in these areas (H value > χ U 2). In residential and commercial areas, the higher the intensity of human activity, the higher the PAE content observed. PAE content decreased progressively from the center to the outskirts of the Houjing night market, suggesting that the increased human and consumer activities inside this commercial hotspot were the main PAE source in street dust. Children had higher estimated daily intakes (DIs) than adults and dermal absorption contributed more to these levels than oral ingestion. Although all calculated DIs were below referenced danger thresholds, street dust PAEs in the area should remain an environmental concern especially since night markets play an important role in Taiwanese/Asian culture and economy. Contrary to other studies, PAEs in this study were found less related to industrial manufacturing activities but highly linked to commercial activities. These findings are relevant for future pollution prevention efforts dedicated to mitigating public exposure to PAEs. Main findings PAE levels in street dust are related to commercial activities. Night markets, an important commercial activity in Taiwan, were found to contribute considerably to PAE contamination in street dust. Graphical abstract Unlabelled Image Highlights • PAE levels in street dust are related to commercial activities. • PAEs were detected in all samples in the range of 5.4–989.2 mg·kg−1. • Estimated PAEs non-dietary DIs are higher in children than those in adults. • Night markets contributed considerably to street dust PAE contamination. [ABSTRACT FROM AUTHOR]

The fungicide chlorothalonil (CHT) has been widely used in the tea orchard due to its high-efficiency and sterilization. It has been reported that repeated application of CHT inhibits soil nitrification process. However, the acute impact of CHT on soil denitrification and associated N 2 O emissions is unclear. This study evaluated nitrate (NO 3 − ) removal, denitrifying gene abundance and denitrifying enzyme activity of tea orchard soil after a 72-h-exposure to CHT. It was found that increasing CHT from 5 to 25 mg kg −1 suppressed the NO 3 − removal efficiency from 74.6% to 54.1%, but increased N 2 O emissions from 23.1% to 94.8%. Following treatment with 25 mg kg −1 of CHT, the abundances of the nir K, nir S and nos Z genes were reduced by 31.6%, 22.1%, and 50.7%, respectively. Alternatively, the declines of the electron transport system activity (ETSA) value and adenosine triphosphate (ATP) content suggested that CHT had an inhibitory effect on microbial metabolism. Enzyme activity studies further revealed that the decrease of nitrate reductase (NAR), nitrite reductase (NIR) and nitric oxide reductase (NOR) activities was the main reason for the suppression of denitrification by CHT. Furthermore, positive correlations were observed between denitrifying reductase activity and the intracellular metabolism, indicating that the decrease in microbial metabolism should also be responsible for the inhibitory effect of CHT on the denitrifying process. Overall, it was found that the acute exposure of soil to CHT could inhibit the denitrification process and significantly increase N 2 O emissions, which might result in destruction of the soil nitrogen cycle and exacerbation of global warming. [ABSTRACT FROM AUTHOR]

Heterogeneous reactions of SO 2 and O 3 with CaCO 3 particles were investigated at a series of relative humidity (RH, 1% to 90%) and 298 K using a diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The uptake coefficients of SO 2 on CaCO 3 at different RHs were obtained for the first time. Our results proved that high RH could substantially promote the formation of sulfate, for which the highest concentration (80% RH and reaction time of 200 min) and highest formation rate in stable stage (85% RH) were 14 times and 43 times that at 1% RH, respectively. The surface products, increment of concentration and formation rate of sulfate changed with RH which were due to the surface adsorbed water (SAW) on the particles. SAW could increase the reactive sites on the particles and thus accelerate the conversion of SO 2 into sulfite, and sulfite could be oxidized rapidly. Liquid-like water layers formed on the particle surface could enhance the ion mobility and promote the aggregation of CaSO 4 hydrates, which could expose more reactive sites and result in additional adsorption of SO 2 . Piecewise equations of uptake coefficient with RH were given and could be referred by model simulation. The results are of importance in understanding the explosive growth of sulfate during severe haze episodes accompanied with high RH. [ABSTRACT FROM AUTHOR]

Long-term nitrogen (N) fertilization affects soil aggregation and localizations of soil organic carbon (SOC), N and microbial parameters within aggregates. The mechanisms of these N effects are poorly understood. We studied these processes in a loamy soil from a 23-year repeated N addition field experiment under a rice–barley rotation. Nitrogen fertilization increased plant productivity and the portion of large macroaggregates (> 2 mm). However, SOC contents in macro- and micro-aggregates remained constant despite an N-induced increase of 27% in root C input into soil. Therefore, N fertilization accelerated SOC turnover. Nitrogen addition increased total N (TN) content in bulk soil and two macroaggregates (> 2, and 1–2 mm), but not in microaggregates (< 0.25 mm). Also, N fertilization increased the phospholipid fatty acids (PLFAs) contents of fungi in the large macroaggregates, but not in the microaggregates. In contrast, the effect of N addition on contents of bacterial and total microbial PLFAs was not apparent. Nitrogen fertilization increased N -acetyl- β -D-glucosaminidase (NAG) activities in the two larger macroaggregate size classes (> 2, and 1–2 mm), but not in the aggregates (< 1 mm). In both control and N fertilization, the large macroaggregates localized more TN, microbial PLFAs, and NAG activities than the microaggregates. In conclusion, long-term N fertilization not only directly promotes soil N resource but also indirectly improves soil structure by forming large macroaggregates, accelerates SOC turnover, and shiftes localization of microorganisms to the macroaggregates. [ABSTRACT FROM AUTHOR]

Background Numerous previous studies have reported that human health risk is extremely sensitive to temperature. Very few studies, however, have characterized the relationship between temperature and mortality in different temperature zones due to the previous conclusions deduced from a regional or administrative division. A research covers different temperature zones was indispensable to have a comprehensive understanding of regional ambient temperature effect on public health. Methods Based on the mortality dataset and meteorological variables of 122 communities in China from 2007 to 2012, a distributed lag nonlinear model (DLNM) was utilized to estimate the temperature effect on non-accidental mortality at the community level. Then, a meta-regression analysis was applied to pool the estimates of community-specific effects in various latitude-effected temperature zones. Results At the community level, the mean value of relative extreme cold risk (1.63) of all 122 communities was higher than that of extreme high temperature (1.15). At regional level, we found temperature-mortality relationship (e.g., U- or J-shaped) varied in different temperature zones. Meanwhile, the minimum-mortality temperature of each zone was near the 75th percentile of local mean temperature except the north subtropics (50th percentiles). Lag effect was also obvious, especially for cold effect. An interesting M-shaped curve for the relationship between cold risk and temperature was detected, while an inverted “U” shaped with a right tail for the heat effect. Such different responses might be attributed to the difference in social-economic status of temperature zones. Conclusion The temperature-mortality relationship showed a distinct spatial heterogeneity along temperature zones across the Chinese mainland. Different characteristics of mortality responding to cold and heat stress highlighted the fact that, apart from the circumstance of temperature, the social-economic condition was also linked with health risk. Our findings suggest decision-makers should take more adaptive and effective measures to reduce health risks in China. [ABSTRACT FROM AUTHOR]