Nitrogen budgets in Japan from 2000 to 2015: Decreasing trend of nitrogen loss to the environment and the challenge to further reduce nitrogen waste.

The benefits of the artificial fixation of reactive nitrogen (Nr, nitrogen [N] compounds other than dinitrogen), in the form of N fertilizers and materials are huge, while at the same time posing substantial threats to human and ecosystem health by the release of Nr to the environment. To achieve sustainable N use, Nr loss to the environment must be reduced. An N-budget approach at the national level would allow us to fully grasp the whole picture of Nr loss to the environment through the quantification of important N flows in the country. In this study, the N budgets in Japan were estimated from 2000 to 2015 using available statistics, datasets, and literature. The net N inflow to Japanese human sectors in 2010 was 6180 Gg N yr-1 in total. With 420 Gg N yr-1 accumulating in human settlements, 5760 Gg N yr-1 was released from the human sector, of which 1960 Gg N yr-1 was lost to the environment as Nr (64% to air and 36% to waters), and the remainder assumed as dinitrogen. Nr loss decreased in both atmospheric emissions and loss to terrestrial water over time. The distinct reduction in the atmospheric emissions of nitrogen oxides from transportation, at -4.3% yr-1, was attributed to both emission controls and a decrease in energy consumption. Reductions in runoff and leaching from land as well as the discharge of treated water were found, at -1.0% yr-1 for both. The aging of Japan's population coincided with the reductions in the per capita supply and consumption of food and energy. Future challenges for Japan lie in further reducing N waste and adapting its N flows in international trade to adopt more sustainable options considering the reduced demand due to the aging population.

Waterborne diarrhoeal infection risk from multiple water sources and the impact of an earthquake.

In the Kathmandu Valley of Nepal, locals depend on multiple water sources due to the limited access to safe water, which is a great global concern regarding its impact on human health. This study aimed to compare the infection risk of diarrhoea from multiple water sources with different concentrations of Escherichia coli among water supply areas and evaluate the impact of changing water sources due to the Gorkha earthquake on the infection risk. The concentration of enteropathogenic E. coli was estimated in samples of piped water, jar water, groundwater, and tanker water, which were collected in the Valley. The volume of each water ingestion was determined based on a questionnaire survey and considering drinking and bathing sources. The highest estimated risk was observed for households drinking groundwater from shallow dug wells, followed by tanker water. The estimated risk implied the regional disparity due to various water sources with different quality. After the earthquake, the ratio of households drinking only jar water increased, and the estimated risk decreased. The damage on piped water supply, the decrease of tanker water availability and the decrease of residents' trust in groundwater quality presumably enhanced the consumption of jar water despite its high price.

Development of an objective water security index and assessment of its association with quality of life in urban areas of developing countries.

A composite metric assessing water security's physical dimension at the micro/ community level is lacking but is essential for setting priorities for program and policy implementations. We prepared an objective index (OI) of water security to measure the physical dimension using a model centered on household water-use behavior in developing countries' urban areas. A cross-sectional household survey (n = 1500) with multi-stage cluster design was conducted from December 2015 to February 2016 in the Kathmandu Valley, which has faced long-term, severe water shortage. A structured questionnaire probed socio-demographic characteristics, water sources, frequency and quantity of water use, cost related to water, etc. A 15-item water insecurity scale was used to measure subjective and experiential dimension of water insecurity. The World Health Organization Quality of Life - BREF was used to measure quality of life (QoL). The QoL has been considered as proxy of well-being in this study. The OI measured differential water security within small cities, the utility's service areas for instance, and identified area-specific key dimensions that need improvement. Overall, the OI and its key dimensions can be useful measures to design water-scarcity averting programs and policies, specific to a particular community's needs. The increased OI values were significantly and positively associated with better physical and psychological health and better social relationship domains of QoL suggesting health implications of water security.

Groundwater use and diarrhoea in urban Nepal: novel application of a geostatistical interpolation technique linking environmental and epidemiologic survey data.

Background: Groundwater is a common domestic water source in developing countries, but is persistently contaminated with enteropathogens. However, studies on determinants of diarrhoea have predominantly focused on piped water. This study examines the relationship between groundwater microbial quality and household diarrhoea occurrence (HDO). Methods: Considering it as a proxy of enteropathogens, this study analysed Escherichia coli concentrations in groundwater wells. Ordinary kriging, a geostatistical technique in geographic information systems, was used to interpolate the E. coli concentration to survey points that had secondary survey data (n=942). The relationship between E. coli and HDO using simple and multivariate statistical analyses in SPSS was analysed. Results: A total of 77% of households used groundwater. One-third of households were without piped-water access (PWA), and these households were significantly more likely to use groundwater than those with PWA. Of the 87 households that reported HDO, 77% were groundwater users. Of the groundwater users, the households with HDO consumed groundwater with significantly higher E. coli concentrations than the households without HDO. Of the households without PWA, the increase in the E. coli concentration increased the odds of HDO (adjusted odds ratio=3.15; 95% CI=1.07-9.22). Conclusion: It is suggested that the groundwater microbial quality is a risk factor for HDO and illustrates this by an application of an interpolation technique relevant for developing countries.

Virological Quality of Irrigation Water Sources and Pepper Mild Mottle Virus and Tobacco Mosaic Virus as Index of Pathogenic Virus Contamination Level.

Irrigation water is a doorway for the pathogen contamination of fresh produce. We quantified pathogenic viruses [human adenoviruses, noroviruses of genogroups I and II, group A rotaviruses, Aichi virus 1 (AiV-1), enteroviruses (EnVs), and salivirus (SaliV)] and examined potential index viruses [JC and BK polyomaviruses (JCPyVs and BKPyVs), pepper mild mottle virus (PMMoV), and tobacco mosaic virus (TMV)] in irrigation water sources in the Kathmandu Valley, Nepal. River, sewage, wastewater treatment plant (WWTP) effluent, pond, canal, and groundwater samples were collected in September 2014, and in April and August 2015. Viruses were concentrated using an electronegative membrane-vortex method and quantified using TaqMan (MGB)-based quantitative PCR (qPCR) assays with murine norovirus as a molecular process control to determine extraction-reverse transcription-qPCR efficiency. Tested pathogenic viruses were prevalent with maximum concentrations of 5.5-8.8 log10 copies/L, and there was a greater abundance of EnVs, SaliV, and AiV-1. Virus concentrations in river water were equivalent to those in sewage. Canal, pond, and groundwater samples were found to be less contaminated than river, sewage, and WWTP effluent. Seasonal dependency was clearly evident for most of the viruses, with peak concentrations in the dry season. JCPyVs and BKPyVs had a poor detection ratio and correspondence with pathogenic viruses. Instead, the frequently proposed PMMoV and the newly proposed TMV were strongly predictive of the pathogen contamination level, particularly in the dry season. We recommend utilizing canal, pond, and groundwater for irrigation to minimize deleterious health effects and propose PMMoV and TMV as indexes to elucidate pathogenic virus levels in environmental samples.

Nitrogen footprints: Regional realities and options to reduce nitrogen loss to the environment.

Nitrogen (N) management presents a sustainability dilemma: N is strongly linked to energy and food production, but excess reactive N causes environmental pollution. The N footprint is an indicator that quantifies reactive N losses to the environment from consumption and production of food and the use of energy. The average per capita N footprint (calculated using the N-Calculator methodology) of ten countries varies from 15 to 47 kg N capita-1 year-1. The major cause of the difference is the protein consumption rates and food production N losses. The food sector dominates all countries' N footprints. Global connections via trade significantly affect the N footprint in countries that rely on imported foods and feeds. The authors present N footprint reduction strategies (e.g., improve N use efficiency, increase N recycling, reduce food waste, shift dietary choices) and identify knowledge gaps (e.g., the N footprint from nonfood goods and soil N process).