Effect of rice-cooking water to the daily arsenic intake in Bangladesh: results of field surveys and rice-cooking experiments.

The effect of rice-cooking water to the daily arsenic intake of Bangladeshi people was investigated. At the first field survey, uncooked rice and cooked rice of 29 families were collected. Their arsenic concentrations were 0.22+/-0.11 and 0.26+/-0.15 mg/kg dry wt, respectively. In 15 families, arsenic concentration in rice increased after cooking. Good correlation (R(2)=0.89) was observed between arsenic in rice-cooking water and the difference of arsenic concentration in rice by cooking. In the second survey, we collected one-day duplicated food of 18 families. As a result, we estimated that six of 18 families likely used the arsenic contaminated water for cooking rice even they drank less arsenic-contaminated water for drinking purpose. We also conducted rice-cooking experiments in the laboratory, changing arsenic concentration in rice-cooking water. Clear linear relationships were obtained between the arsenic in rice-cooking water and the difference of arsenic concentration in rice by cooking. Factors that affect arsenic concentration in cooked rice are suggested as follows: (1) arsenic concentration in uncooked rice, (2) that in rice-cooking water, (3) difference in water content of rice before and after cooking, and (4) types of rice, especially, the difference between parboiled and non-parboiled rice.

Rapid and comprehensive indicator for evaluation of performance of treatment processes and of river waters.

Naturally occurring UV active compounds, commonly present in almost all source waters, can be rapidly monitored by their ultraviolet absorbance at 260 nm (E260). Herein, the extent of correlation between the E260 and the removal efficiency of the hazardous contaminants, endocrine disrupters and dioxins, were investigated using various treatment and river source waters. The detection of various types of hazardous contaminants using sophisticated analytical methods, such as high resolution gas chromatography (HRGC)/high resolution mass spectrometry (HRMS) and high performance liquid chromatography (HPLC)/inductively coupled plasma (ICP)/mass spectrometry (MS), as well as various short-term bioassays, can require hours or even days for results to be obtained. The removal of the E260 correlated well with those of individual contaminants, such as endocrine disruptor chemicals and dioxins, with the various treatment processes employed. In the plots of the endocrine disrupters against the DOC/E260, a correlation was found with the endocrine activity of the Korean/Japanese river waters employed in this study.

Arsenic contamination of groundwater in Nawabganj, Bangladesh, focusing on the relationship with other metals and ions.

Serious arsenic contamination of groundwater in Bangladesh has been frequently reported and is of great concern. In this research, repeated water sampling from the same 10 tubewells in Nawabganj municipality, Bangladesh, was conducted and analysed, focusing on the seasonal variation of water quality and the relationship among arsenic and other metals and ions. For the seasonal variation of water quality, arsenic and iron concentrations were higher in the rainy season in general although the tendency was not consistent and it depended on the tubewell and the time. Correlation between arsenic and iron could not be observed in this study (r = -0.01) when using all cases. This was because no correlation was observed in the higher arsenic concentration range. Arsenic removal by co-precipitation with coexisting iron is known as one of the locally applicable techniques in Bangladesh, but the result from this study suggests that some additional treatments such as the extra injection of iron should be performed in some cases, especially where the arsenic concentration is high. The correlation between arsenic and other substances was also analysed. As a result, manganese (r = 0.37), molybdenum (r = 0.33) and sulfate ion (r = -0.33) significantly correlated with arsenic (p < 0.05). The negative correlation between arsenic and sulfate ion implies the dissolution of arsenic into groundwater under reductive conditions although there are some exceptional cases.

The effect of bisphenol A and chlorinated derivatives of bisphenol A on the level of serum vitellogenin in Japanese medaka (Oryzias latipes).

2,2-bis (4-hydroxyphenyl) propane or Bisphenol A (BPA), has been reported to behave as an endocrine disrupter below acute toxic levels, and is widely present in the water environment. Although BPA is easily chlorinated, very little is reported on the effect of chlorinated BPA to the aquatic organisms. In this study, the estrogenic activities of BPA and its chlorinated derivatives were evaluated by the induction of vitellogenin (VTG) in the serum of mature male Japanese medaka. In addition, the effect of sodium hypochlorite on the decomposition of BPA was tested. The relative potencies of estrogenic activities of chlorinated BPA descended in the order 3,3'-diCIBPA>BPA> or =3-CIBPA>3,3',5-triCIBPA, and no estrogenic activity was observed in 3,3',5,5'-tetraCIBPA. Lowest Observed Effect Concentration (LOEC) and No Observed Effect Concentration (NOEC) for both 3-CIBPA and 3,3'-diCIBPA were 500 microg/L and 200 microg/L, respectively. LOEC for 3,3',5-triCIBPA was >500 microg/L. When BPA was reacted with sodium hypochlorite (24 hours; residual chlorine at 1 ppm), however, complete decomposition of BPA and its chlorinated derivatives was observed. The decrease in BPA and its chlorinated derivatives paralleled the decrease in estrogenic potency evaluated by the induction of vitellogenin (VTG) in the serum of mature male Japanese medaka.

The effect of chlorination of estrogenic chemicals on the level of serum vitellogenin of Japanese medaka (Oryzias latipes).

Mature male medaka were continually exposed to four chemicals, p-n-nonylphenol (p-n-NP), nonylphenol (p-NP), bisphenol-A (BPA) and 17beta-estradiol (E2) to evaluate their estrogenic activities in the laboratory. In order to understand the effect of the chlorination that is applied widely in water and wastewater treatment, the above chemicals were chlorinated and then exposed to mature male medaka. Furthermore, in the case of vitellogenin, a is a female specific protein induced by the exposure to test waters containing the above chemicals after 5 weeks, medaka was returned to uncontaminated tap water to determine whether male medaka have a self recovery function from the effect of estrogenic chemicals. Much greater vitellogenin compared to the background levels were induced in the male medaka by separate exposure to 100 microg/L of p-NP, 1,000 microg/L of BPA and 0.05 microg/L of E2. The levels of vitellogenin increased with increasing exposure periods. The relative potencies of these chemicals descended in the order of E2>>p-NP>BPA. Vitellogenin levels inducible by these chemicals were drastically reduced as a result of the chlorination for 24 hours. However, a moderate increase in hepatocyte somatic index (HSI) meant the hepatic fatness was observed as a result of chlorination. It is not clear at this stage whether or not the formation of chlorination byproducts is responsible for this moderate increase in HSI. The vitellogenin concentration of male medaka exposed to chemicals for 5 weeks decreased gradually after return to the uncontaminated water. However, the vitellogenin concentration did not return to the initial normal levels even after 5 weeks. A clear relationship between the serum vitellogenin concentration and the hepatic vitellogenin concentration was also found. Since quantitative analytical procedures for hepatic vitellogenin are easier than those of the serum vitellogenin, measuring the estrogenic effect using the measurement of vitellogenin in liver is recommended.

Study on self-purification capacity for organic pollutants in stagnant water.

Polluted water is abandoned or stored untreated in many places. Especially, small water bodies such as ditches, ponds, wastewater tanks, etc. have not yet well been considered. The self-purification stabilizes the wastewater, but oxygen supply limits the biodegradation process. In the natural environment, approximately 3 g oxygen can be dissolved per m2 per day if the water is completely deprived from dissolved oxygen; this is the magnitude of self-purification capacity. To improve the quality of polluted water with higher oxygen demand than natural reaeration capacity, enhanced aeration is required. The laboratory experiment disclosed that water trickling onto the water surface or shallow stirring of water less than 10 mm in depth increased the mass transfer rate significantly. At the same time, the methods were found more efficient than bubbling aeration of large-scale treatment plant in terms of energy input against oxygen supply. Though it is an efficient method, elaborate application will be necessary since the mass transfer rate is not as high as bubbling aeration.

Sustainable development of water services industry.

The world population is expected to increase up to 8 billion by 2015. Most of the cities in the world are scattered around the fresh water resources. These cities and villages have their own interests and they constitute a power order. Therefore, we have been trying to harmonize these cities and villages in the usage of fresh water resources and the discharging of wastewater as well, by using an engineering means of water treatment. However, fresh water resources, which are essential to our lives, have a constant amount of circulation with a period of one week to ten days. The science and technology of the water environment should recognize the limit of fresh water resources for the sustainable development of society, because the water service industries are the essential infrastructure of the community. In order to implement an appropriate risk management it is necessary to identify the goal of environmental management considering the social, natural and economical conditions. The energy-dependent technologies should be reconsidered to consume less energy and undertake more resource conservation engineering. Water science and technology cannot supply all the answers, therefore more comprehensive water management systems should be developed by other sectors, such as the food production industry.

Non-point pollution of Ishikari river, Hokkaido, Japan.

We researched the Ishikari river, Japan's second-longest river, to clarify the characteristics of non-point pollution by comparing flux characteristics of chemical components in three periods of one year: the snow melting period, the typhoon flooding period and the stable period. We found non-point pollutants present in great amounts because a large amount of suspended matter, which is contained in soil, flows into the river and concentrations of nutrients and organic matters do not decrease in a short time in the flooding period by rain and in the snow melting period.

Estrogenic influences of estradiol-17 beta, p-nonylphenol and bis-phenol-A on Japanese medaka (Oryzias latipes) at detected environmental concentrations.

Mature male medaka were continuously exposed to 0.005, 0.0-5 or 1.0 ppb of estradiol-17 beta (E2 or 0.1, 10 or 100 ppb of p-nonylphenol (NP) or bis-phenol-A (BPA). Female-specific proteins (Fsp) were induced in medaka exposed to 0.005 ppb of E2, 0.1 ppb of NP, or 10 ppb of BPA. Concentrations of 0.005 pbb of E2 and 0.1 ppb of NP corresponded to concentrations of these chemicals detected in river water in Japan. The abilities of the 3 chemicals to induce Fsp were E2 > NP > BPA. Embryonic medaka were exposed to E2, NP and BPA under conditions of static-renewal for 200-230 days until pre-maturity. Survival ratios of medaka exposed to E2 and NP declined in concentrations more than 25 ppb and 50 ppb, respectively. The groups of medaka exposed to E2 had individuals with testis-ova or abnormal gonad. There was no male in exposure to 1.0 ppb E2. When exposed to 100 ppb of NP or BPA, abnormal gonad was also detected. Abnormal anal fin (female-like) was observed in male exposed to 100 ppb of NP. The LC50 values for each of the 3 chemicals were much higher than the concentrations detected in water in the environment--the 3 chemicals were considered to have no lethal effect on medaka in aquatic environments. However, exposures to E2 or NP at environmental concentrations induced Fsp. BPA also had the ability to affect medaka as an environmental estrogen, although its extrogenic activity was weaker than that of E2 or NP.

Statistical approach towards point sources of groundwater pollution with tetrachloroethylene: a field study.

Tetrachloroethylene contamination of well water occurred in a primarily residential area. To search for point source(s) of tetrachloroethylene contamination, 91 water samples were collected on three separate occasions from 41 shallow wells scattered in the areas. Three methods of groundwater level analysis (limited to 30 wells), cluster analysis of water quality indicators and contour drawing of tetrachloroethylene concentrations were applied. The former two analyses showed that the pollution took place in aquifers of two terraces out of the three in the polluted area. The contour mapping demonstrated the presence of three spots of suspected pollution sources as the estimated points of highest tetrachloroethylene concentrations. The available information suggested the existence of a facility with possible use of tetrachloroethylene in the past.