nan Hiroyuki

Determination of the abundance of δ15N in nitrate ion in contaminated groundwater samples using an elemental analyzer coupled to a mass spectrometer

A rapid method for measuring the delta15N of nitrate ion in water samples using an isotope ratio mass spectrometer coupled to an elemental analyzer system (EA-MS) was investigated. The water should be removed from the analytical sample before measurement with this system. We investigated the application of a super-absorbent polymer resin powder to various water samples. Each 1 mg of polymer resin powder can absorb about 50-100 mg of solution depending on the concentrations of major ions. Only samples which contain more than 100 mg l(-1) of nitrate-nitrogen are suitable to be absorbed by the polymer resin for the determination of delta15N of nitrate. Preconcentration by rotary evaporation was necessary for dilute samples but the temperature should be kept below 60 degrees C. The polymer resin (about 8 mg) containing the nitrate was directly analyzed using an EA-MS after being oven-dried at 80 degrees C. Good accuracy (precision +/- 0.3%) for delta15N measurements of nitrate-nitrogen in a sample without any isotope fractionation effects during pre-treatment was observed. Results for delta15N of nitrate in contaminated groundwater samples collected in the spring at a tea plantation area in Shizuoka, Japan, were from 9.8 to 10.6%, which were close to the delta15N abundance in organic fertilizers.

CU, CO AND NI CONTAMINATION INDEX FOR RIVER USING RIVER INSECTS AND RIVER PLANTS

Useful species as an index of metal contamination n eeds a high metal concentration in a contaminated area and low metal concentration in a non-contaminated area. Moreover, it needs a high metal concentration factor. Metal concentrations of moss were high in the Cu mine area (31 to 21,000 and 2 to 200 mg/kg-dry for Cu and Co) and were low in the other ar eas (2 to 87 and 2 to 33 mg/kg-dry for Cu and Co). Ni concentrations of caddice-worm were high in the ser pentinite area (9 to 590 mg/kg-dry) and were low in the other areas (2 to 74 mg/kg-dry). Moss had the highest concentration factor (160,000, 4,600 and 59,000 for Cu, Co and Ni) among river plants. Therefore, it was clarified that moss was useful sp ecies for an index of Cu, Co and Ni contamination among river plants based upon its metal concentration and concentration factor. I n river insects, metal concentrations of crane fly larva we re high in the Cu mine area (50 to 1,400 and 1 to 8 2 mg/kg- dry for Cu and Co) and were low in the other areas (11 to 130 and 0.7 to 10 mg/kg-dry for Cu and Co). Crane fly larva had the highest concentration factor for Cu (46,000) and also kept high concentration factor for Co (2,700) among river insects. Ni concentrations of caddice-worm were high in the serpentinite area (52 to 220 mg/kg-dry) and were low in the other areas (0.3 to 20 mg/kg-dry). Caddice-worm had the highest Ni concentration factor (22,000) among river insects. Therefore, it was clarified that crane fly larva wa s useful species for an index of Cu and Co contamination and c addice-worm was useful species for an index of Ni contamination based upon their metal concentrations and concentration factors.

Salinization of the Glenelg River in Southwest Victoria, Australia

Southwest Victoria, Australia, has many lakes and rivers, most of which cannot be used for agricultural or domestic purposes because of their high salt content. The Glenelg River, located 300 km west ofMelboume, is the largest river in southwest Victoria and an important ecological and agricultural water resource. Although local precipitation i s more than 600 mm per year, the Glenelg Rivers salt content exceeds l/l O that of sea water with electrical conductivity (EC) values of several thousand J.LS/cm. In these reaches it cannot be used as drinking or irrigation water. Historically, river salinization has been attributed to (l) evaporation and concentration during reservoir storage, irrigation, and subsequent reuse; (2) displacement o f shallow saline groundwater during irrigation; (3) erosion and dissolution of natural deposits; andlor (4) inflow of deep saline and/or geothermal groundwater (MooRE et al. 2008). Hydrogen and oxygen stable isotopes and chloride concentration have proved useful for determining salt sources (DRUHAN et al. 2008). The purpose of our study was to determine the origin o f the sai t and how it concentrates in the Glenelg River using oxygen and hydrogen stable isotopes and chloride content.

Analysis of organic nitrogen compound in domestic sewage in Yamato River using a social experimental test

A social experimental test to reduce the amount of organic pollutant from households was performed along the Yamato River in Japan. The river is polluted with organic compounds in sewage and has the highest biological oxygen demand (BOD) of all rivers managed by Japanese government. Because of this, the government carried out a cleaning campaign to improve the water quality in the Yamato River between 1985 and 2005 by constructing river purification facilities and sewerage systems. We evaluated these efforts of the sewage systems and the river water cleaning campaign by measuring the change in the amount o f nitrogen compounds and by pollutant load analysis.

INFLUENCE OF PHYTOPLANKTON BY TOTAL NITROGEN AND CALCIUM ION AT DAM AND WEIR IN THE KINOKAWA RIVER BASIN

The phytoplankton and their species were analyzed in the Otaki dam, the Sarutani dam and the Kinokawa flood gate. The Otaki dam, the Sarutani dam and the Kinokawa flood gate are stagnant condition. Ca+ concentrations in the Otaki dam and the Kinokawa flood gate were over 11 mg/l. Ca+ concentration in the Sarutani dam was equal to or less than 10 mg/l. Total nitrogen concentration in the Kinokawa flood gate was over 0.8 mg/l. Total nitrogen concentration in the Otaki dam and the Sarutani dam was equal to or less than 0.7 mg/l. In summer season blue-green algae increased in the Kinokawa flood gate but dinoflagellate did not increase. On the other hand, dinoflagellate increased in the Otaki dam. Then, blue-green algae increased, when total nitrogen concentration is over 0.8 mg/l. Dinoflagellate increased, when Ca+ concentration is over 11 mg/l.

LIVING LIMIT OF LARVA OF DRAGONFLY IN RIVERS WITH DOMESTIC SEWAGE INFLOW IN THE SOUTHERN PART OF OSAKA

Living limits about Na and Cl concentrations of larva of dragonfly were studied. As Na and Cl concentrations in river water increased, the number of larva decreased and species composition of larva changed from Stylogomphus suzukii to Calopterx atrata. Na and Cl concentrations were thought to be mixing ratio of domestic sewage and domestic sewage was thought to contain toxic substance. Davidius nanus was distributed widely in the river water from low to high mixing ratio of domestic sewage. Living limits of maximum Na and Cl concentrations for Calopterx atrata and Davidius nanus were 50 and 80 mg/l. The values were living limit of all larva of dragonfly observed in the southern part of Osaka. In the long term, the living limits of maximum Na and Cl concentrations for larva of dragonfly were 38 and 59 mg/l. When anionic surface active agent is 3.8 to 6.2mg/l, larva of dragonfly disappeared.

Behavior of soil nitrogen and leaching of metal elements from arable land

In Japan, large amounts of fertilizer nitrogen are applied to tea plantations. We collected samples of tea plantation soil each season for a year. Samples were analyzed for their contents of various inorganic chemicals and total N. Nitrogen was present mainly in the top 0 to 30 cm of soil. However, at times the concentration of nitrate N in the soil water was more than 35 mg L−1, even in the deepest layers. The contents of various metal elements in the soil were examined. Ba, Fe, Sr and Zn contents were high in the top 0 to 30 cm of soil. But Al and Mn contents were not always high in the top 0 to 30 cm of soil. From the correlation analysis among contents of various inorganic chemicals, it was suggested that increased leaching of Al, Mn, and Zn from tea plantation soil occurred with increased nitrate N concentration.

ESTIMATION OF BOD LOADS CONSIDERING WATER TEMPERATURE IN THE YAMATO RIVER CATCHMENTS

Calculated Pollutant load per unit production and actual pollutant load of Yamato River were estimated. The actual pollutant load was determined from measured flow rates and concentrations. As a result, actual BOD load showed seasonal changes with low values of summer and high values of winter. The change depended on temperature because a rate of decomposition of organic compound depends on temperature. The actual BOD loads between two pints along the Yamato River with no branch river and no drainage were measured and a rate of decomposition between them was calculated. The calculated seasonal BOD load from pollutant load unit production method including rate of decomposition showed the same pattern of the actual BOD load. The total BOD load value by unit production including decomposition calculated method was 4 times of the actual load. As BOD was not measured at flood condition, the actual BOD did not include floating material at the condition of high flow rate and then was smaller than the calculated load per unit production.

CHARACTER OF COD VALUES WITH FLOW RATE CLAFIED BY ONE HOUR AUTOMATIC MEASUREMENT IN THE YAMATOGAWA RIVER

COD was previously measured from sampled water. Then 1 month measurement does not include flood condition because of safety for sampling. 1 hour measurement is automatically sampled and measured in situ at station and then includes flood condition. To clarify difference between 1 month measurement and 1 hour measurement , using both measuring results of flow rate, COD, TB and EC values of the Yamatogawa river, effect of flow rate on COD , TB and EC values was clarified. COD and TB values increased with flow rate. EC value decreased as flow rate increased . The relationships between COD and flow rate, TB and flow rate were very similar. Therefore , COD was more strongly influenced by floating material than soluble substances because TB was concentration of floating material . Using the relationships between COD and flow rate, COD loads were calculated. As a result , the COD load calculated by the 1 hour measurement was more about 2 times than the COD load calculated by the 1 month measurement.

CHANGES OF SUBSTANCES DERIVED FROM DOMESTIC SEWAGE IN YAMATOGAWA RIVER BASIN

Seasonal Concentrations of BOD, NH4+-N and interfacial active agent derived from domestic sewage were high in winter and low in summer. The concentrations decreased with an increase in water temperature. Generally, river water contains organic compounds and Cl- derived from domestic sewage and Cl- was quite stable in rivers. As the ratios of BOD/Cl- and NH4+-N/Cl- decreased down the stream and changed seasonally, organic compounds were thought to be decomposed during flow. NO3--N/Cl- which organic compounds were finally decomposed into, also decreased down the stream and were high in winter and low in summer. NO3--N was thought to be used for photosynthesis because pH, DO values and chlorophyll concentration of the Yamato river increased with temperature and decrease of NO3--N concentration.