著者

名川 吉信 植松 喜稔 西 末雄

出版者

公益社団法人 日本水環境学会

雑誌

水質汚濁研究 (ISSN:03872025)

巻号頁・発行日

vol.7, no.1, pp.31-38, 1984-02-29 (Released:2009-09-10)

参考文献数

14

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The reactions of proteins and their major constituent amino acids with chlorine in water have been studied and the following results are obtained.1) Proteins have the potential properties of yielding chloroform or total organic chloride (TOCI) as similar extent to humic acid.2) At the pH range of 4-10, the amounts of chloroform formed from proteins increase with increasing pH, whereas the yields of TOCI show maxima at pH8.5. In the cases of amino acids, the amounts of chloroform and TOCI formed vary depending on the kinds of amino acids. However, the pH dependencies in the chloroform formations from amino acids and in the TOCl formations from certain amino acids which yield higher levels of TOCl are similar to those in the cases of proteins.3) The amounts of chloroform and TOCl formed from proteins can be expressed as the following equation. [OCl]=K[P][Cl]mtnWhere [OCl] is the concentration of chloroform or TOCl, [P] is the concentration of protein, [Cl] is the concentration of chlorine, and K, m, and n are the parameter.

著者

亀田 豊 益永 茂樹

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.29, no.9, pp.553-560, 2006 (Released:2010-01-09)

参考文献数

22

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There is growing awareness of the need to evaluate the long-term effects of wildlife populations, not only in terms of the level of short-term effects on individuals, but also in terms of much subtler, multigenerational effects particularly for long-term conservation of ecosystems. Here, we show population genetic structure of Pseudorasbora parva in the Kanto region and estimate the main stressors to influencing genetic variability and genotype. Genetic diversity within a population was significant among sampling sites, but no significant relationship was detected between genetic diversity and contaminants, such as polycyclic aromatic hydrocarbons (PAHs) and heavy metals, because of many types of stress effects and random genetic drift. On the other hand, cluster analysis of the fluorescence intensity of individual DNA fragment profiles measured by amplified fragment length polymorphism (AFLP) analysis identified five genotypes: two existed in many sites in the Kanto region, and three existed in only a few sites. Genetic diversity or genotype proportion in a population at the sites where these two genotypes was dominant were also significantly related to dissolved PAH, dissolved fluoranthene, dissolved benzo[k]fluoranthene and benzo[k]fluoranthene concentrations in sediments. Finally, the population genetic structure in eight sites along the Nogawa river was evaluated. These results showed genetic diversity and genotype proportion changed discontinuously in some sites, because of changes in PAH concentration and limited migration.

著者

川田 邦明 横山 ひろみ 尾崎 邦雄

出版者

公益社団法人 日本水環境学会

雑誌

水質汚濁研究 (ISSN:03872025)

巻号頁・発行日

vol.12, no.5, pp.306-312,295, 1989-05-10 (Released:2009-09-10)

参考文献数

34

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新潟平野中央部の金属製品工場が多数立地する地域でトリクロロエチレン, テトラクロロエチレン, 1, 1, 1-トリクロロエタン, cis-1, 2-ジクロロエチレンおよび1, 1-ジクロロエタンによる地下水汚染を確認した。cis-1, 2-ジクロロエチレンと1, 1-ジクロロエタンは, 各々, トリクロロエチレンと1, 1, 1-トリクロロエタンの分解生成物と考えられた。また, この地域の地下水の水質は, 沖積層では大部分がアルカリ土類炭酸塩型であり, 洪積層では地域により異なっていた。そして, 低沸点有機塩素化合物による汚染は沖積層のうち最も浅い層を中心に進行したが, 洪積層には達していないと考えられた。さらに, 金属製品工場にある深さ10mの井戸における地下水の通年調査から, 低沸点有機塩素化合物の濃度は地下水位や, 調査井戸またはその周辺にある井戸の使用状況の変化による影響を受けると考えられた。

著者

関谷 卓見 竹谷 公貴 天野 佳正 町田 基

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.33, no.11, pp.175-179, 2010 (Released:2010-11-10)

参考文献数

27

被引用文献数

4 5

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The blue-green alga Microcystis aeruginosa and the diatom Cyclotella sp. were grown in Wright's cryptophytes medium with various mass ratios of total dissolved nitrogen to phosphorus (N/P = 1, 10, 50 and 100) at different temperatures (15, 20 and 25°C). Similar experiments at lower nitrogen and phosphorus concentrations but using the same N/P ratio were also carried out. At high nutrient concentrations (N = 0.5-50 mg·L-1 and P = 0.5 mg·L-1), Cyclotella sp. was dominant at all N/P ratios at 15°C, but M. aeruginosa became a superior competitor at 20 and 25°C at N/P≠ 1. Generally, Microcystis blooms tend to occur at a low mass ratio of total nitrogen (TN) to total phosphorus (TP), i.e., TN/TP ratio. However, this study clearly showed that a high N/P ratio favored the growth of M. aeruginosa. Moreover, the growth of both algae was controlled significantly at all N/P ratios at low nutrient concentrations (N = 0.05-5 mg·L-1 and P = 0.05 mg·L-1). Therefore, it could be concluded that M. aeruginosa dominance occurs at temperatures above 20°C and is promoted at a certain level of nutrient concentrations (N > 0.5 mg·L-1 at P = 0.5 mg·L-1 and/or P > 0.05 mg·L-1 at N = 0.05-5 mg·L-1) rather than N/P ratio.

著者

中島 淳 長岡 裕 大垣 眞一郎

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.19, no.8, pp.664-667, 1996-08-10 (Released:2008-01-22)

参考文献数

6

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Water quality of Laguna de Bay, the largest lake in the Philippines, was survyed as a small joint survey of Japanese and Philippine NGO groups. The lake water had relatively high concentration of SS caused by resuspending silt and fine clay from the bottom sediment due to shallow water depth and strong wind. Chl a concentration was low in spite of high concentrations of nitrogen and phosphorus. Trihalomethane formation potential test showed high formation of bromine compounds due to intrusion of sea water into the lake. Relatively high concentration of SS, COD, nitrogen and phosphorus was observed at the mouth of the most polluted tributary.

著者

藤田 豊 中村 玄正

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.30, no.4, pp.197-203, 2007 (Released:2010-01-09)

参考文献数

26

被引用文献数

2 3

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Historically the water quality of Lake Inawashiro has been kept very good in terms of COD and other variables. The reason for this is due to the very low concentration of phosphorus in the lake for example, 0.003mg · l-1. Additionary, the primary production of phytoplankton is controlled at very low level. The authors studied the mechanism by which floc removes phosphorus that is produced in the acidic Nagase River. The major results obtained from this study are as follows : (1) The floc produced in the Nagase River coagulate and then settle as phosphorus sediment. (2) The floc has a particle size distribution that is effective for coagulation and then for phosphorus sedimentation. (3) The main components of the floc are Fe, Ca and Al. (4) When floc was added to the river water, the concentration of phosphorus decreased and the AGPM also decreased.

著者

川西 琢也 川島 博之 茅原 一之 鈴木 基之

出版者

公益社団法人 日本水環境学会

雑誌

水質汚濁研究 (ISSN:03872025)

巻号頁・発行日

vol.13, no.3, pp.180-188,162, 1990-03-10 (Released:2009-09-10)

参考文献数

13

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土壌浄化法の大きな問題点のひとつである目詰まりについて, その機構の解明と, 浸透不良を防ぐための排水供給量の推算を試みた。まず, 微生物が土壌透水係数に及ぼす影響を, カラム実験により実測した。土壌中の微生物密度には最大値が存在し, それに対応する最小の透水係数が求められた。次にトレンチを模擬した小型の実験装置で, 人工下水を定水頭差で浸透させ, 浸透水量の減少を追跡した。浸透水量は20日程度で定常状態となった。カラム実験の結果と, 土壌中の微生物分布, TOCのバランスから, 目詰まりの機構を明らかにした。さらに, 以上の知見をもとに数理モデルを作成し, 浸透不良を生じないための排水供給量を推算した。計算の結果, BOD100mg・l-1の排水に対して, 40l・m-1 (trench) day-1という許容排水供給量が得られた。

著者

原本 英司 片山 浩之 大垣 眞一郎

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.32, no.6, pp.315-320, 2009 (Released:2010-01-09)

参考文献数

26

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The occurrence of pathogenic viruses and indicator microorganisms in water samples from a wastewater treatment plant in Japan was investigated monthly from July 2003 to June 2004. Forty-eight samples of raw sewage, treated sewage before chlorination, effluent after chlorination, and reclaimed water after advanced wastewater treatment using sand filtration and ozonation were subjected to a virus concentration method using an HA electronegative membrane, followed by virus detection using a TaqMan PCR method. Noroviruses of genogroups I and II were detected in all 12 raw sewage samples, showing much higher concentrations in winter, an epidemic season. Corresponding to the occurrence in raw sewage, the concentrations of noroviruses in treated sewage and effluent also increased in winter. The concentrations of enteroviruses and adenoviruses in the tested samples were relatively constant compared with those of noroviruses. Noroviruses and adenoviruses were still detected even after advanced wastewater treatment, but the concentrations of these viruses were much lower than those in the effluent samples. Viruses were removed by wastewater treatment as effectively as indicator microorganisms (total coliforms, Escherichia coli, and F-specific phages), suggesting that sewerage systems can contribute to reducing the load of pathogenic viruses discharged into aquatic environments.

著者

小山 次朗 渡辺 牧子

出版者

公益社団法人 日本水環境学会

雑誌

水質汚濁研究 (ISSN:03872025)

巻号頁・発行日

vol.12, no.6, pp.353-357,351, 1989-06-10 (Released:2009-09-10)

参考文献数

11

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中禅寺湖にアワが発生した1984年以来, 湖におけるアワの観察および湖水中糖類ならびにタンパク質濃度の測定等を行ってきた。その結果, アワは毎年8-9月に出現することが明らかとなった。また, アワが多量に出現した時の湖水中糖濃度が1.0mg・l-1以上と高いことおよびタンパク質濃度がほとんど0.1mg・l-1以下であったことから, 糖類がアワの主成分の1つと考えられた。そこで湖水中糖濃度と一次生産量を比較した結果, 後者の値が低く, 植物プランクトン由来の糖類が, アワ発生時の湖水中糖類の主要な起源ではないことがわかった。また, 秋季には落葉等から溶出したと考えられる高分子多糖類が多くなることが判明した。以上のことから, 中禅寺湖に発生したアワの主成分の1つである糖類は, 植物プランクトン以外の植物体, つまり落葉および水生植物から溶出した高分子多糖類に由来するものと考えられる。

著者

風間 真理 小倉 紀雄

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.24, no.11, pp.745-749, 2001-11-10 (Released:2007-02-22)

参考文献数

20

被引用文献数

3

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The aim of the investigation is to show how the Ayu (Plecoglossus altivelis), a fish living in clean streams, can return to an urban river that believed to be polluted in the past. It was found that the ammonia nitrogen concentration had decreased remarkably, by monitoring of the water quality at the river. Due to the qualitative improvement of the sewage treatment water that is the river's main discharge source, the ammonia nitrogen concentration was decreased. Ammonia is an important substance for the survival of the creature; and a safe level, which makes the Ayu's survival possible, was estimated.

著者

梶原 葉子 山田 真知子

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.20, no.3, pp.185-192, 1997-01-10 (Released:2008-01-22)

参考文献数

30

被引用文献数

1 4 9

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Quantitative sampling of sessile animals and monitoring of water quality in Dokai Bay, northern Kyushu, Japan, were carried out from 1991 to '92 for four times to evaluate the water condition in the bay, Kitakyushu heavy and chemical industry area.In this study, seventy four species of sessile animals ware collected, which include Mytilus galloprovincialis, Limnoperna fortunei, Crassostrea gigas, Mytilopsis sallei, Balanus amphitrite, Balanus trigonus, Balanus eburneus, Ciona intestinalis, and Styela plicata. These nine reprentative species in the bay showed characteristic distribution and seasonal occurrence patterns. We noted eight immigrated species of sessile animals including an ascidian Polyandrocarpa zorritensis recorded first in Japanese coastal water.Eutrophic level of water in Dokai Bay was classified according to the occurrence of the sessile animals in the bay. Water conditions of the inner most and central parts of the bay were classified as hyper eutrophic level, and those of the bay mouth were at intemediate one between hyper eutrophic and eutrophic levels. We suggest that six dominant species, including a mussel M. galloprovincialis, are useful as biological indicator organisms of hyper eutrophic level of coastal water.

著者

山本 昭子 西山 直宏 吉田 浩介 山根 雅之 石川 百合子 三浦 千明

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.33, no.1, pp.1-10, 2010 (Released:2010-01-10)

参考文献数

58

被引用文献数

3 11

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Linear alkylbenzene sulfonate (LAS) is an anionic surfactant widely used in laundry detergents. The environmental safety of LAS has been extensively reviewed in various chemical safety assessment programs worldwide. In this paper, we report an LAS aquatic environmental risk assessment of Japanese rivers using a high-tier assessment approach. For the exposure assessment, river water monitoring data of more than 400 samples were used to determine predicted environmental concentrations (PECs) which were then verified with the AIST-SHANEL exposure model. For the effect assessment, a statistical extrapolation approach using chronic ecotoxicity data was used. Toxicity data were normalized to the average alkyl chains found in the environment (C11.3) and to that of commercial LAS average alkyl chains in Japan (C11.8). Mesocosm data were also normalized to determine the predicted no-effect concentration (PNEC) in the environment. The 95th percentile PECs for detected concentrations in Japanese rivers were 32 to 45 μg/L, and the PNECs were 270 (C12) to 530 (C11.3) μg/L based on mesocosm data with an assessment factor of 1 and supported by data from the statistical extrapolation approach. The PEC was about 10 times lower than the PNEC. From the result of the risk characterization, it was concluded that the aquatic environmental risk posed by LAS in Japan is low.

著者

津野 洋 宗宮 功 西村 文武 小島 岳晴

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.20, no.4, pp.246-253, 1997-04-10 (Released:2008-01-22)

参考文献数

10

被引用文献数

1

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The low pH of acid precipitation is buffered by soil to some extent, but the pH-buffering mechanism also releases variety of materials, which may cause wide effect on the aquatic environment. So in this research, we have permeated artificial acid rain through soil to examine the quality of soil leachates. As a result, we have found that some soils around Lake Biwa have reached the aluminium buffer range which has possibilities of deteriorating the aquatic ecosystem. We have also found that phosphorus included in the leachate causes great effect on algal growth potential under low pH condition as 4.0.

著者

山本 富久 中曽根 英雄 黒田 久雄 加藤 亮

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.29, no.9, pp.561-564, 2006 (Released:2010-01-09)

参考文献数

31

被引用文献数

1

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We surveyed the water quality of irrigation reservoirs in a tea field catchment. The study area was located in Shizuoka Prefecture, Japan. Water in some of the reservoirs showed alkalinity because of the photosynthesis of aquatic plants. On the other hand, water in one irrigation reservoir showed acidity because of nitrogen fertilizer. The NO3-N concentration increased how many times owing to large runoff from a watershed when rainfall was strong and heavy accumulation. The Changes in NO3-N concentration were small throughout the season when was light rainfall. The average of NO3-N concentration in the irrigation reservoirs was about 5 mg·l-1.

著者

村上 和仁 今富 幸也 駒井 幸雄 永淵 修 清木 徹 小山 武信

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.21, no.11, pp.757-764, 1998-11-10 (Released:2008-01-22)

参考文献数

25

被引用文献数

2 4

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The Seto Inland Sea in Japan is well known world-widely as one of the famous enclosed coastal sea, which is surrounded on all sides by the three large islands of Honshu, Kyushu and Shikoku, and is the largest inland sea in Japan (area ; 22,000Km2, total coastline ; 6,600Km, average depth ; 38m). In order to obtain the information about the environmental condition in the Seto Inland Sea, the quantity and distribution of macrobenthos, especially Annelida which is considered to indicate the sedimental condition, were investigated from the 425 sedimental samples as the Investigation for Environmental Management of the Seto Inland Sea (IEMS), which conducted from 1991 to 1996.The results obtained can be concluded as follows:1) The macrobenthos mainly observed in the Seto Inland Sea were Lumbrineris longiforia, Paraprionospio spp., Prionospio ehlersi and Theora fragilis, which were recognized as the indicator species of organic pollution.2) 16species of Spionidae were observed, i.e. Paraprionospio sp., Prionospio ehlersi, P. cirrifrea, Spiophanes sp. and so on.3) The species number and the individual number of Annelida were decreased with increase of muddy ratio, IL, COD, T-N, T-P and TOC.4) The species number and the individual number of Annelida were decresed with increase of Cd, Cu, Ph, Zn and Mn.5) Organic pollution was suggested especially in inner bay area because of dominations of some species of Annelida, Spionidae.

著者

今井 章雄 福島 武彦 松重 一夫

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.22, no.7, pp.555-560, 1999-07-10 (Released:2008-01-22)

参考文献数

30

被引用文献数

4 6

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Aquatic humic substances (AHSs) from the eutrophic Lake Kasumigaura were isolated using XAD-8 resin. The effects of these isolated AHSs on the growth of Microcystis aeruginosa cultures were evaluated. M. aeruginosa was isolated from algal blooms in Lake Kasumigaura and grown in a chmically defined medium under iron limitation. The production of siderophores, iron-specific complexing agents, by M. aeruginosa was also examined. Under iron limitation, M. aeruginosa was confirmed to produce hydroxamate-type siderophores; however, they were not effective to enable substantial recovery of the growth rate. The fulvic acid (lower molecular-size fraction of AHSs) isolated from Lake Kasumigaura was found to significantly inhibit the growth of M. aeruginosa. The fulvic acid at 2 mg dry weight l-1, the same level as in the lake, significantely inhibited the growth of M. aeruginosa even though siderophores were produced. This inhibition was probably due to a deficiency of iron caused by iron complexation with the fulvic acid. These results suggest that AHSs, through their iron complexation reactions, may play an important role in formation of M. aeruginosa algal blooms.

著者

佐々木 久雄 西村 修 須藤 隆一

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 = Journal of Japan Society on Water Environment (ISSN:09168958)

巻号頁・発行日

vol.22, no.7, pp.581-586, 1999-07

被引用文献数

2

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People usually evaluate the amenity of water environment by transparence to look at water. Water transparence is measured by transparency or transparency by cylinder test. However, these methods have some defects such as difficulties in measuring at shallow and clean waters, because transparency is limited by water depth and transparency by cylinder test is limited by length of a cylinder. Moreover, the lack of objectivity is pointed out, since transparency measuring is due to personal sensitivity. To conquer these problems, we designed a measuring method of horizontal transparency, and developed a measuring equipment by using an eye-test chart and a waterproof camera. We applied this method to water quality investigation of Matsushima Bay, Miyagi prefecture, and studied the characteristics of horizontal transparency comparing with transparency, transparency by cylinder test and so on. The results obtained were as follows; (1)Horizontal transparevcy has superior objectivity, because evaluation by plural number of people diminish personal errors. (2)Horizontal transparency is possible to express water transparence quantitatively without any limits, though conventional methods cannot apply to relatively clear and shallow waters. (3)Horizontal transparency has a very good correlation between not only transparency but also turbidity and suspended solids that are mainly affect to transparency. (4)The sense of visitors and fishermen about the water quality of Matsuhima Bay can be represented by horizontal transparency.

著者

高見 徹 丸山 俊朗 鈴木 祥広 三浦 昭雄

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 = Journal of Japan Society on Water Environment (ISSN:09168958)

巻号頁・発行日

vol.22, no.1, pp.29-34, 1999-01-10

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In the short-term bioassay using Porphyra yezoensis conchospores, it is basically important to clarify the most appropriate exposure period and end point to evaluate the effects of toxicants on the growth of Porphyra yezoensis conchospores. In this study, short-term bioassays (120 hours) were conducted on copper (Cu) and monochloramine (NH2Cl), which have different chemical characteristics. Three kinds of end points (survival ratio, germination ratio and growth ratio) at exposure periods every 24 hours were compared to define the most appropriate exposure period and end point.The minimum LOECs (lowest-observed-effect concentration) for Cu occurred at exposure period of 96 hours in the three kinds of end points. The 96-h LOECs from the survival ratio, the germination ratio and the growth ratio were 0.046 ± 0.026mg Cu·l-1 (n=5), 0.033 ± 0.027mg Cu·l-1 (n=5), 0.021 ± 0.019mg Cu·l-1 (n=5), respectively. The minimum LOECs for NH2Cl occurred at exposure period of 96 hours in the survival ratio and the growth ratio of 0.093 ± 0.026mg Cl2·l-1 (n=5) and 0.038 ± 0.016mg Cl2·l-1 (n=5), respectively. The minimum LOEC (0.036 ± 0.000mg Cl2·l-1, n=5) for NH2Cl from the germination ratio occurred at the exposure period of 48 hours.Therefore, taking into account of the simplicity of bioassay and its sensitivity to toxicants, it is concluded that the most appropriate exposure period and end point is 96 hours for Cu and 48 hours for NH2Cl judging from the end point of the germination ratio.

著者

高見 徹 丸山 俊朗 鈴木 祥広 三浦 昭雄

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.22, no.1, pp.29-34, 1999-01-10 (Released:2008-01-22)

参考文献数

22

被引用文献数

1

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In the short-term bioassay using Porphyra yezoensis conchospores, it is basically important to clarify the most appropriate exposure period and end point to evaluate the effects of toxicants on the growth of Porphyra yezoensis conchospores. In this study, short-term bioassays (120 hours) were conducted on copper (Cu) and monochloramine (NH2Cl), which have different chemical characteristics. Three kinds of end points (survival ratio, germination ratio and growth ratio) at exposure periods every 24 hours were compared to define the most appropriate exposure period and end point.The minimum LOECs (lowest-observed-effect concentration) for Cu occurred at exposure period of 96 hours in the three kinds of end points. The 96-h LOECs from the survival ratio, the germination ratio and the growth ratio were 0.046 ± 0.026mg Cu·l-1 (n=5), 0.033 ± 0.027mg Cu·l-1 (n=5), 0.021 ± 0.019mg Cu·l-1 (n=5), respectively. The minimum LOECs for NH2Cl occurred at exposure period of 96 hours in the survival ratio and the growth ratio of 0.093 ± 0.026mg Cl2·l-1 (n=5) and 0.038 ± 0.016mg Cl2·l-1 (n=5), respectively. The minimum LOEC (0.036 ± 0.000mg Cl2·l-1, n=5) for NH2Cl from the germination ratio occurred at the exposure period of 48 hours.Therefore, taking into account of the simplicity of bioassay and its sensitivity to toxicants, it is concluded that the most appropriate exposure period and end point is 96 hours for Cu and 48 hours for NH2Cl judging from the end point of the germination ratio.

著者

橋本 温 河井 健作 西崎 綾 松本 かおり 平田 強

出版者

公益社団法人 日本水環境学会

雑誌

水環境学会誌 = Journal of Japan Society on Water Environment (ISSN:09168958)

巻号頁・発行日

vol.22, no.4, pp.282-287, 1999-04

被引用文献数

5

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In order to investigate the occurrence and indicator of protozoa in water, water samples were collected from 11 points along the Sagami River and its tributaries for 9 months. The concentrations of Cryptosporidiurn oocysts, Giardia cysts and potential indicators (presumptive Clostridium perfringens spores, Escherichia coli, coliforms, aerobic spores and turbidity) were analyzed. Cryptosporidium oocysts were detected at 10 of the 11 sampling points (GM 34 presumptive oocysts·100l-1, 24 confirmed oocysts·100l-1) and Giardia cysts were detected at all sampling points (GM 30 presumptive cysts·100l-1, 12 confirmed cysts·100l-1). Based on a regression analysis, the concentrations of presumptive C.perfringens spores and E.coli were significantly correlated with the concentrations of protozoa. In a multiple regression analysis, the concentration of presumptive C.perfringens spores, E.coli and aerobic spores were selected as explanatory variables for the protozoan concentrations. The results indicated that presumptive C.perfringens spores, aerobic spores and E.coli were useful indicators for protozoan contamination.