Junko Shindo

Nitrogen flow associated with food production and consumption and its effect on water quality in Japan from 1961 to 2005

Abstract Using statistical data, we evaluated food supply and consumption in terms of nitrogen flow to clarify its effects on water quality from 1961 to 2005 in Japan. We revised a nitrogen flow model to incorporate food production, trade and consumption as well as nitrogen mineralization of crop residues and livestock manure and denitrification. Food consumption increased steadily from 1961 to the mid 1980s and has been almost stable since then. There was a notable increase in the consumption of livestock products. By 1996, consumption had risen to fivefold the 1961 level of consumption, but it has been stable since then. We concluded that the demand for food reached a maximum in the 1990s. The increasing demand for animal feed was filled by an increase in the imports of coarse cereals until the 1980s and of oil cakes until now. As the consumption of food and animal feed increased until the mid 1980s, the nitrogen load to the environment also gradually increased during this period, after which it tended to decrease. We estimated the nitrogen concentration in river water for 8 km × 8 km grid cells from 1961 to 2005 and compared these estimated values with measurements taken at more than 4000 points from public bodies of water in 1998. The spatial distribution and prefectural average of the estimated nitrogen concentration roughly corresponded with the measured values, and both indicate that food supply and consumption have had considerable effects on water quality in Japan.

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.

Assessing the infection risk of enteropathogens from consumption of raw vegetables washed with contaminated water in Kathmandu Valley, Nepal

To assess diarrhoeal risks from enteropathogenic Escherichia coli, Giardia and Cryptosporidium from consuming raw spinach, cabbage, carrots and tomatoes in Kathmandu Valley, Nepal.

A novel water security index and well-being at micro level 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

Abstract 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.

Input-output budget of nitrogen and the effect of experimentally changed deposition in the forest ecosystems in central Japan.

To evaluate the current nitrogen (N) status in Japanese forests, field measurements of rainfall, throughfall, litter layer percolation, and soil solution percolation were conducted in a red pine stand (Kannondai) and a deciduous stand (Yasato) located in central Japan. N input via throughfall was 31 and 14 kg ha yearand output below rooting zone was 9.6 and 5.5 kg ha year in Kannondai and in Yasato, respectively. Two thirds of input N were retained in plant-soil systems. Manipulation of N input was carried out. Ionic constituents were removed from throughfall with ion exchange resin at removal sites and ammonium nitrate containing twice the N of the throughfall was applied at N addition sites periodically. SO4 output below 20-cm soil layer changed depending on the input, while NO output was regulated mainly by the internal cycle and effect of manipulation was undetected. These Japanese stands were generally considered to have a larger capacity to assimilate N than NITREX sites in Europe. However, N output fluxes had large spatial variability and some sites in Kannondai showed high N leaching below rooting zone almost balanced with the input via throughfall.