 J. Hot Spring Sci. 0* ++3ῌ+-- ,*+*ῌ῎ΐῐ῍ῑῌῒῐ῎῏
9:;<+ =>?@+ ABC


,,

+

 

+3

,,

+

/

 DEFG+,0

Coloration Mechanism of Green Colored
Hot Spring Waters
Nobuki TAKAMATSU+, Mitsuo NISHIOKA+, Natsuki FUKUSHIMA+
and Naoko KUWAHARA+

Abstract
Chemical analyses, UV-Vis absorption spectrum and Electrospray Ionization Mass
Spectrometry (ESI-MS) measurements of hot spring waters of Kunimi in Iwate Pref. andKumanoyu in Nagano Pref., which are the representative green colored hot springs inJapan, were conducted to elucidate their coloration mechanism. Reproduction experiments
veriﬁed a hypothesis “The green coloration is due to the composition with yellow color of
the polysulﬁde ion produced by the reaction with sulfur and hydrogen sulﬁde in neutral
pH and the blue color brought from the Rayleigh scattering of light by sulfur or calcium
carbonate colloidal particle”. There were all sample waters in the stable region of HSwhen we plotted pH and ORP values on a diagram of Eh-pH concerning for the sulfur
chemical species. The maximum absorption at ,-* nm which is due to hydrogen sulﬁdeion and the absorption band of -**ῌ/** nm which participates in yellow color were foundin UV-Vis absorption spectra of the green colored hot spring waters. A lot of peaks ofHSx were observed in the ESI-MS measurement of the green colored hot spring water ofKumanoyu. This x was mainly 1, in addition, there were 0, 2 and +*. It was conﬁrmed thatthese hot spring waters contain polysulﬁde ions Sx,. The various size ﬁne particles ofcalcium carbonate and sulfur were found in the hot spring waters of the Kumanoyu andKunimi by scanning electron microscope observations. From these results, it is concluded
that the above hypothesis can be supported as for the green coloration mechanism.
Key words : green colored spring water, polysulﬁde ion, Rayleigh scattering, ESI-MS,
UV-Vis absorption spectrum, Kumanoyu hot spring, Kunimi hot spring

῏

+

῍

!"#$%&'()*+,#&-./01'23456 78 ,1.ῌ2/+*  ,ῌ,ῌ+ + Department of Chemistry, Faculty of Science, Toho University, Miyama ,ῌ,ῌ+, Funabashi-shi, ,1.ῌ2/+*, Japan.

119   

UV-Vis   !"#!$%&'()
 ESI-MS *+,. /012,345 67898:;<75 =>?@.ABC(%&'C1DEFG(%&'H1BC IJKLMNB
O"%P! 1!%Q$R"@G#C1S$@G C.TUVW%,X&YG5Z
'1[(\],-^5 _5 pH C ORP ),B('@`YG Eh-pH *+@#"aYGC +13,b HS 1c-d@.e_A.5 /_5
1 UV-Vis  ,YGC ,-* nm 0f@(%&'@ghYGCij87Gk1 l -**/** nm @B@`2YGCij87G 3lm4<75 ,YGn15
1
ESI-MS ,-TC HSx 1o$l6pq.;<75 r1 x = 1 ,7@_As 6
18 0 2 +* *+ltGrClu9^5 v+1rC98 ,YGr781
@ wq=(%&' Sx, l.e_A.GC9<75 n15
@= IJK
LMBO"%P1:! l.e_A.GrC,;xy< z:{|}*+Em4_
5 r781rC98 = (%&'@GBC~=:! @G!%Q$R"@G#1S$@GC.T+1W%l>0875Cij87G (%&' !%Q$R" ESI-MS, UV-Vis   n1
$$P : 
 wq
5+ῌ ῏ ῍ ῐ ῎@=? #  *+*,_5b1l.e_A.G
/0@`@l87A:5 ?1=pA87A.5l #,YG

p9861h =BO"%P1R"/0@Gb1EtG Bj1 CD@tGEFNJPG - HI*+1#h =KQJO"%PEts /0=!%Q$R"EtG Ohsawa et al., ,**,
rClJ<7

1@`YG`@lKLYrC@*^5 61CD1G1#

MN@.A1bOZ87 P1QRQ /0 # @ S@TUYGJ&
Q%@G!%Q$R"/0 # l0<7 610S@^AMNlgrGb
1C9<7A.G 1V8 ,**-W 

1 h@`_A=C+2<7A.*.C.^A. w(E,YGXYZ*^

C_A= wq

[ n15_` *+l ¡87G r781

Q\ 

Q\ ]=B,¢£ EtGC.T¤a1bc,¥l d , e=fgE=hEtGl  , e=¦ 98fg§1i1¨jE 7@I(©ª<«1M( 7@¬­I( @^Alk@M(YGB,¢£=BO"%P! l/0@`2_A.GrClp lm

 p1I  1l ? 98 #? ,  _A.G

,=FZ6

E=*.ln n ® o ¯1 5 ;°s

Ohsawa et al., ,**3 Nlm?±¯15²*+1³I´µ¶1 ·¸P¹Q$'= Fe, 1

 /0@GCBO"%P! 1pq1!%Q$R"@G#1re1ºS@^A%<7A.G »s8 ,**- r78=³I1B¢t^uEtGl ,YG=Ets BO"%Pl`2_A.G19 Fe, *+1QRQ v)l¢°7A.Gr
C@G19=wEts ah1R"C¼*G/0l@`2_A.G½xbtG
nE= fg@.Ah,YGwq

n15,yzC_   UV-Vis   ~=v)1;xy< z:{|}#!$%&'()!" ESI-MS ,-. 67898:;<75UVW%,X&YG5Z

1[(\]@^A 

120

1(

1/0,89@YGrC,IZC_5

 0*  ,*+*,  ,+  Fig. +



   !"#$ ! %&'()*+,- 

./01- Cl + HCO- +2345 6789:;<2=  !>"#$?@%&AB5C@2 D'ῌE+31+()>FGHEIFJ#$K* Fig. , L+,-./MNOEIῌ0
NPQ*1RAB5CF)-
 23S , T4567*+, 0 T89 K* , T4567*+, . T89! 2UC=*:VW45 ,. ;X<YZ[C@2 W=%\[]>?^*_@`!

=%@A ,** L, K*@A 1, L -W

(a5=bU4*?@`! 89*BCDcde$f@*?@`! "E/F%GHI? 4567g/hiGhJ?@2 89K
/LMG2j[C3=

Nkl-T2@ ,**/ O 3 m ,0

,1

P`no ,**1 O +* m ,, ,- P K*T2@ ,**/ O +* m +* P%CpCW 4
5`no8945qQ*r"?

ESI-MS RSTqQ ,**2 O + m +* PK*W

@rU?
,,

BVsWn_@tu=-! *vXYw$3xZ- %3-yz{ |}~ CS-+** *T2@RS*2  [\? Nkl- Ohsawa
et al. ,**, V]-RS*_ RS ^_ CIE  +3-+ OS*`-Y$ XYZ Yxy Y CIE+3-+ Y *T2@Y? XYZ Y J R a G  B b D]Jc2@de?=-fg*T2@ Y _fx hy f  - T`-Y$3- ij x, y*.-+*+ *.-+0, RS? x, y *Dk-o %Dk(kegj45lhm( nm *`8? RSd>nfV]-_
w!- DoP`no!*po?@2q*rRRS*_ st-s@RS*_ qQ*C67uvw45W xyz SOLAX XC-+**A*T2@ m( l-1*

12* nm, {fA -,*** cd /*^o? oV¡|?@

3*V¡45-RS? |}GxyzX |}GRS~X¢RST(:£X

*n¤? % nPQ*u]$¥T¦*?@RS?
,- 



`noK*W 45`no89@" CUSTOM uf CT-/**§m ¨u pH  HM-,*P©8ª«# ORP, §m ¨u pH  HM-+.P

pH 

¬f

EC, §m ¨u¬f CM-+.P RS*_i F ­~{®fS] Na K Ca, `no Mg, J¯°
f] Cl `no SO., /01±²³´µ¶] DIONEX u QIC IONCHROM ANALYZER
H,SiO- °f] ·®¸¹1b] Puºuf U--,+* Cu, `no Fe, »¼½³dF] ICP-AES SEIKO u SPS-*** ^ ICP dF *T
121  



Fig. + A location map of Kunimi hot spring in Iwate Prefecture and a photograph ofthe open-air bath of Kunimi hot spring.

Fig. , A location map of Kumanoyu hot spring in Nagano Prefecture and a photographof the open-air bath of Kumanoyu hot spring.

  !"#$% &'()*+,'-,ῌ. ῔῎῏ῐῑ῍ΐῒ./0*123#45-67896:; 4<=>?5@*A)B122

 0*  ,*+*



  !"# $% pH, &!'( )  *+!%,-./0/%!1   3 #&!2345 6*&!2!78
9,   * &7890   &:;<8&789 S,O-,
=&789 SO-,

&789 SO., >?1 /@A&!B , CDE FG

5:; !789 Sx, HI A !"#JK ALM5
+,4%NO@,.+UV-Vis 

PQR,STUVWXY Z[\%]^_3  %`a@Y
bcd

+ cm

%L ef gg h U--,+* h ,** /** nm ijklmnd

!"@/@ o#V%!V$IHI@%p  o#V%%q.r!V$I@%p!789%, 1 %C& ijklmnd!" UVklmn
d's@,.,ESI-MS

!789!"#(t)%1)*]^ !V789&!+u

Steudel, ,**- vwx,.L,4% !V789+u Kleinjan et al., ,**HS x+ ῌ2S2 ῌ Sx,HMH?.L &yz{|-}" (yM~dyz{| S0, S/, S.,%~dy S-

,

,

S,

$

>J1

/@ H".%H?.L@ /.%H?.L@ ,3tV%y3  !V
789+u0 51 Kleinjan et al., ,**/  V( /L2H
N3%,3 0% !7895H?.L5!.L
Gun et al. ,**.  HS,O- v HS3 *+# !"# ESI-MS %,-&"1%?@ A !789%,41@ TUV
56%@V dk789!7 896 Cold-ESI 96 JMS-T+**S%,- ESI-MS !"@9J@!789 Sx,  FG2 x  :O !78

ESI-MS !";M<=.L@>%p% 

 %p(> G789 GX3 7ῌ 2 mῌz %@5- ?
.%17 8;,/

V@vA V(%¡ E%,-54F.L/L72BG%,CDg7

ER,S

Eg GH . ¢%+'I BGJ , ¢%'I1£gGH5K¤+ 7%pL51¤+

E.Lg5¥* @ ;M5?3C E 7 E g@*GH& 1.BG%,-HI Eg¡ E¦§L 7BG51£1g$B%¨L5HI ©ª5«  EN¬£gN¬&O*
A* /@ 7 E­*3GH®y¯..L
Ohsawa et al. ,**, °±d² ³´-@B

7B· *.+*

8M7 E%Nµ¶*../ mm P¸%"@ &% 7BG%Ct&y| *.+* *../ mm B·¹;7 E +., mm DEB·¹;¡ E
HI.r5Qº.L »RM ,**-

¼N AY½µL@g Eg hS123 

 







 !"#$%

&'() *.*-*.*. mm *+,*-./0*1 2  3 ,**-

.4567 89(:;<=>/5?<@4AB< )34/*CD34E
CaCO- ,/+FG6HIJ%KLM4E*CD34EN!"#$)O!"#$*P
QRS!"#$(TE ?U?%V<E!"#$1W?5/E9X%Y4Z4%
>[E0*)\]5?^
cd e(%

_!K`/*CD34E "KP

QRS%abQ) fg%#h($?^%i[E*jk4E%(  Kl/5%m )

E0*)(n</*CD34E Y0(&KP QRS1o?pEU>Y%'( %)U3Cq? r6HI*+%&%P QRS%'( >st%HpK;u?
Ca,CO-, ῌ CaCO- %,v -w . > Ksp [E* /w0K1[E'(x Saturation
Index SI ) SIlog Ca, CO-,ῌKsp (2D34 /w0Ky[E-w,vz%34 %5{K<E |Q  * pH U3;uU3}] CO-, 6 *? Ca, 6 >Y4Z4%~7K%? %K89?5 SI >u? 00(# %~7)# %~7>
#Q%:;<K#  >89?5}]
 SEM  

,/,=&>|>  abQcd  *.+ mm (fg? f%%
6HI?@>AE]KBC DEC > JSM-/2**LV (¡q? ¢£¤¥*)
6HIF

>¦,

- ./0-+ FG6HIJ%%GH I%§¨%&'> Table + K©? FG%G
H I%J%ª.)K5 02 cm st(T7 J%%GH I%J%ª.) /3 cm st(T, 043%&')K5«LMKONN§*.4E§OPQ N : /**/// nm, ON :////1* nm %<UKo[E1 GH()RH%9X) §O1QPQSKa¬? Fig. -04)H­®¯°TKH,5%i[EUV %1y?5/E*±.4E WH¯%

², ¯°%UV )_³ X%YPQ*QPQ% 1´µ¶«Ko[E1 RH®Z[% <
=()

r%

1V<E YPQ

%O1 1-./ 0*KH7-·%§O1%i[E_!\1CD34E
-,   pH, !"#$ %&'()*+,-FG  6HIJ%    %r  G
H I%& pH, Pi¸¹Cº ORP
6HI C » ]^ %&'> Table ,K©? rU3*+z^9.4E¼_
K6@E pH, Pi¸¹Cº C»]^ %%`) n^</*/p0*1kU,"K ORP %%i)½<^
124

n<a%b>

Table + The data of hue wavelength (WL) of Kunimi andKumanoyu hot spring waters.
Sampling location

Sampling date

WL/nm

Kunimi-open air
Kunimi-indoor+
Kunimi-indoor,,0-Oct-*/,0-Oct-*/,0-Oct-*/

/0+
//1
//-

Kunimi-open air
Kunimi-open air
Kunimi-indoorKunimi-indoor.

,,-Oct-*1,--Oct-*1,--Oct-*1,--Oct-*1

/03
/0/0,
/0-

Kumanoyu-open air
Kumanoyu-indoor+*-Oct-*/+*-Oct-*//0,/1,

 0*  ,*+*

!"# $ : -/+ mV,  : +/0 mV %&'( $ : ,-/ mV,  : , mV )*+,-. ,**1 /01 23 4'56
EC 78 9:;< =>? @ABCDE@FG HI JKLMNE O P

Q9:R STUV= WXYZ[ WXG\YZ[ ]^V_`YZ[ a=;bcN 23defῌ]^V_`ῌWXG\g-. h idefῌUTj_`ῌ]^V_`ῌeXgῌWXG\g-;
Dc
k

Fe dlmno Cu dlBp

ppb ZqrqsAa=;<t Table -EN; Bpuvwx+yz{E@-ῌ- ῔῎῏ῐῑ῍ΐῒ|}R !~8 pH 

pucNB@  Eh-pH 
@qTrYS` Pourbaix Diagram E   ef!~8d|}

Eh-pH  Krauskopf, +301

B@ pH  ORP

^@k "  e!G\YZ[ ¡B;Dc¢@ Fig. .
@;¢ef!~8e!G\YZ[
Fig. - Examples of calorimetric data shown on the
xy-chromaticity diagram established by Commision Internationale d’Eclairage (CIE) in +3-+.
The boxed color photographs were taken in,**1. Photograph (A) was taken in indoor bathtab -, photograph (B) in open-air bath tab at thetime of the ﬁne sky and photograph (C) inopen-air bath tab at the time of the cloudy sky.

Table ,a=;£b Table . @R

B¤¥{E+;e!G\YZ[;X!
¦§eXYZ[B D¨©e!G\YZ[eXYZ[ ªB X!7 «+{¬+­¡®¯ S, O-, % Sx, +°;*t LMNE

The water chemistry of Kunimi and Kumanoyu hot spring waters.

Water
Sampling Temp.
date
ῌ

pH

Kunimi-source
Kunimi-open air
Kunimi-indoor+
Kunimi-indoor,,1-Oct-*/,0-Oct-*/,0-Oct-*/,0-Oct-*/

/+40
./40
.,4.
-34/

Kunimi-source
Kunimi-open air
Kunimi-indoorKunimi-indoor.

,--Oct-*1,,-Oct-*1,,-Oct-*1,,-Oct-*1

Kumanoyu-source +*-Oct-*/
Kumanoyu-open air +*-Oct-*/
Kumanoyu-indoor +*-Oct-*/

Sampling location

HS

Content/mg L+

ORP
EC
Alk
ῌmV ῌSm+ ῌmeqL+ Na

KCa, Mg,

Cl

SO., H,SiO-

043+
14,,
14+3
14+2

-/+
-/,
-/3
-/3

*4.1+
*4.-.
*4.0*4.0-.+4-04,
-342
-241

3*3
20+
3*3
3-/

-+40
,24,
-+4.
-/4/

+,2
++*
+*.
+*/

2.41
1+4+
1343
1241

,*/
+3,*,*+

,-1
,,,-/
,-+

+-/
3,4334,
334/

.,4.
.14,
.14.
-141

14,1413
1403
14/*

-.,
-03
--1
-0-

*4./*4.**4.,0
*4.,.

-24,
-/4*
-141
-04.

2/0
2,2-3
3,1

,24+ +,*,14- 214.
,04. +,0,043 +,*

1-42
1/4/
1043
104,

,/3
,/,
,/.
,/0

,01
,3,0+
,30

2-42*4*
2,42
2+4/

.142
.*41
..4+

14,2 -12
14.1 -00
14., -2+

*4+.*
*4+,3
*4+,2

04/*
/412
/421

+*- /4*03340 /4-+
304/ /4,.

,*4+
+240
+243

1,43
2.4,
0.40

,10
--+
-/1

++2
+*/
+*1



+1+12
+10

125



-ῌ-ῌ+ 



UV-Vis ῒΐ῎ῐ῍῏ῑ

!"#$% + &'()* UV +,-./01"23456 Fig. / 789:

5;<= ,-* nm >?7@A+,"B4-./01CD9:E FGH +30- IJKLM6NLMOPQ!RS+,-./016TU) LM"VWX7'()EY7Z[5\]^O6+,-./01^O"_`) H,S RSab"cd*ef6+,Cgh) Xb ci1
jkblI ,-* nm >?7@A+,Cm5[6"nop7B)E Ellis and Golding +3/3 7;:q [:I HS 7Zr456e< s8  UV +,-./01 Fig. 0 t uv HS 7;56wx9:5 ,-* nm >?7@A+,Cy9:5C z:;{|}|~7t"f;<=+,C89: ~l *e5;<78x5 [:IFGH +30- CLO0k!RS
+,-./016)* ,/* nm >?;{|}
Table - The data of total Fe and Cu contents of Kunimi
and Kumanoyu hot spring waters.
Sampling location

Sampling date

Fe
/ppm

Cu
/ppm

Kunimi-source
Kunimi-open air
Kunimi-indoor+
Kunimi-indoor,,1-Oct-*/,0-Oct-*/,0-Oct-*/,0-Oct-*/*4.0*4-*4-1*4..

*4**4**4*.
*4*-

Kunimi-source
Kunimi-open air
Kunimi-indoorKunimi-indoor.

,,-Oct-*1,,-Oct-*1,--Oct-*1,--Oct-*1

*4+1
*4+*
*4+0
*4*-

*4*,
*4*,
*4*,
*4*,

Kumanoyu-source
Kumanoyu-open air
Kumanoyu-indoor+*-Oct-*/+*-Oct-*/+*-Oct-*/*4***4**.
*4**-

*4**+
*4**,
*4**,

Fig. . The ﬁgure which plotted the datameasured at the source of Kunimi (,**1)
and Kumanoyu hot spring (,**/) on the
ORP-pH diagram created by Krauskoph(+301).

Table . The data of H,S, HS content and Saturation Index (SI) for CaCO- of Kunimi andKumanoyu hot spring waters.

126

Sampling location

Sampling date

H, S/mgL+HS/mgL+SI (CaCO-)

Kunimi-source
Kunimi-open air
Kunimi-indoor+
Kunimi-indoor,,1-Oct-*/,0-Oct-*/,0-Oct-*/,0-Oct-*/

/,41
,/4+
,/4+
,34.

1+42
0,41
//4+
/343

*41+3
*42/+
*412*41,1

Kunimi-source
Kunimi-open air
Kunimi-indoorKunimi-indoor.

,--Oct-*1,,-Oct-*1,,-Oct-*1,,-Oct-*1

-04/
34.1
34-+
+14/

224*
1241*42
1+43

*43*/
+4,2
+4-1
+4+.

Kumanoyu-source
Kumanoyu-open air
Kumanoyu-indoor+*-Oct-*/+*-Oct-*/+*-Oct-*/

04,/
34-3
242-

+24/
-24+
-.4*

*4.-*
*4/*1
*4.21

 0*  ,*+*

  !"#$%&'()*+',-./0& 1234567%$89:;<=>?@AB5CDE&' HS &!FG<H

IJKLM=6NO.HPQ62 Fig. 0 R%H
HS " S,O-, S&TU NO.H SO., S& 'V

W$%& XYZ +30- -**/** nm  ![ \]H^"_`S&a(bc`S2 R%"^ 'd)Sef"0&5ghE&2i jklmB
ln5op289 q 'm^5jkl8rcsmB
ln5op289 ^  UV-Vis!:;<=>?

@AB5tu2 Fig. 1 vw Fig. 2 xyH ,-* nm z
Fig. / Absorption spectrum of the watercolored in green after having left thewater of source of Kumanoyu hot
spring for a few days.

{ HS |}E&'~%& !FG<"#$%2"
7FG<H@"?TE&'JLM=6 bc`S2  y^ 62l89/H

Fig. 0 Change of absorption spectrum of the water+ colored in green after having left the waterof source of Kunimi hot spring for a few days. ,) and -) are the spectra of the water after
having left it more for / and +/ days, respectively.

Fig. 1 Change of absorption spectrum of the water+ made by conduction H,S into the distilled water.
,) and -) are the spectra of the water after having left it more for ++ and +0 days, respectively.

127   

Fig. 2 Change of absorption spectrum of the water+ made by conduction H,S into the water
after dissolving elemental sulfur in distilled water. ,) and -) are the spectra of the water
after having left it more for / and +/ days, respectively.

Fig. 3 ESI-MS spectra of water colored in green after having left the water ofsource of Kumanoyu hot spring for a few days.

,-*,/* nm  HS !"#$%&'#()*+,$- -**/** nm ./01/2/$%&'#()345' 67389:;<3=<"#$$2>?@ABCDE F/ -**/** nm GH#()IJKLῌMN UV-Vis OPGQRSC#T;U/VT0WXY
Sx, 3Z["#VT0WXY\]^/_`,abcd#$efA'# g/hGijklm

n + opq:r<s<:E]^/_`,ab Fig. / Gij Fig. 0 2 -**-/* nm ()I3
l5'EF$t5 F/()IJVT0WXY Sx, i#2/$uvA'#
-ῌ-ῌ,

ESI-MS ῍῎g/h/m/wx\yQR z{|}~YYb+   *.*,/ mm c9:E]^n ESI f:E$F VT0WXY Sx, J H 3:E HSx /cA' /
T;U x J 1 n /. 0 2 +* 3Z[:RQ#F$3&tDE Fig. 3 kl/w
x\J/E/Y{Y3McdDEE ESI-MS f/$/W128

 0*  ,*+*

  ESI-MS  !"#$%&'%(!"#$  )$*+
,-./012)3456789:;<=$ >$-?@!"%A-?BCD 1 .E@
?F G5 Steudel and Eckert, ,**- 7H=34567"IA ,-./0 Sx, ?
 JC%K567L+M43ANO%K57P I=5-. 
-.+CaCO- 

Table . +L SI QRSF:)$ T3UV* SI  SI* %K567"I CaCO-+W)3XYI*+W)3AZ[῏%K567N\<=$ 667]+M43A]
"I^_+`a<=5Zb+M43A >$^_+M43A CaCO- cdef5g2hijkK567F:)345 667῍lmῌnopqrstu+v>#$orw
xy X z{|+}#3~  / s / N\<=$677h%K#$
-., 

M}* *.+ mm %Z rwC ¡{|M}¢{|£¤¥F Figs. +*+- +:)$ L*¦§rw+¨43¡{|%-?M} ©ª« Fig. +*, Fig. ++ ¬4­®¯°±<=$ ¢{|"IAῐ¦§rw+-? Fig. +,, Fig. +- N\<=$ ²³ ©ª«[῏´QR£¤7Aµ¶· Fig. +* +I=5}¸!@/¹ /s/!X²³ ©ª«£ºC¦§)345ijk»¼3¬47H 5 6=I67"IL*7A-?M}
²³ ©ª«ºC*½+¦§)3457£῎<=5

Fig. +* Examples of SEM photographs of the substance on Nuclepore menbrane ﬁlter(*.+ mm pore size) after ﬁltering of the Kunimi hot spring water. (A) : Indoor bathtab+ (,**/) (//*), (B) : Source (,**/) (+*,***), (C) : Indoor bath tab, (,**/)(+1, ***) and (D) : Open-air bath tab (,**/) (-*,***).

129

 



Fig. ++ Examples of SEM photographs with point analyses by EDX of the substance on
Nuclepore menbrane ﬁlter (*.+ mm pore size) after having ﬁltered the Kumanoyu hot
spring water. (A) : Source (,**/) (,/,***) and (B) : Open-air bath (,**/) (+,***).

Fig. +, Example of SEM mapping image with point
analyses by EDX of the substance on Nucleporemenbrane ﬁlter (*.+ mm pore size) after havingﬁltered the Kunimi hot spring water.

Fig. +- Example of SEM mapping image with point
analyses by EDX of the substance on Nucleporemenbrane ﬁlter (*.+ mm pore size) after havingﬁltered the Kumanoyu hot spring water.

-ῌ/ ΐῑῒ῎῍ῐ῏ !"#$%&'()*+,-./0 Sx, 1,234.5678
9:;<=>?@ABCDE'F1GH F"#*+,-./0)'2#%#1IJ>
130

 0*  ,*+*

 ! "#$%&'()*+#
,&'-./012 3 4*516
: /1* nm 67

789: ; <89:; nm =>?@ABCDE-F

G*5 H+I+JK -LM1 6789: ;N4OP- QR ST
#UVW 4*51

X: - L -YZB[+ \Q1] + +./ g -F
G*57:^- ORP (  -/* mV _U` a:@7bcDE-de pH - 1 f

gQ1

4Q16789: ; Fig. 2 h

i -jk-" lmnQop
qrJK -LM1 *r stu( 2*nm ?@ABCDE vw%xyz{  :|} PZ -de JK -LM1 6
789: ; B

6789: ;

?@ABCDE-de1: ; C~JK--cQ1

Fig. +. Q1 6789:

N /1* nm;<Fig. +. Calorimetric data shown on the xy-chromaticity diagram established by Commision Internationale d’Eclairage (CIE) in +3-+. Photographs are (A) : distilled water, (B) : the watercontaining polysulﬁde ion and (C) : the water
added CaCO- (average particle size῍2* nm)
into (B).

! 6789: ;?@ABCDE-de1: ;<N /0+ nm

!M1 ,qrῌ!

:6789]FG '" er+-0  

!QR# 3-LM1( 4$"R.%QR&'(! 404$ ^-()QR"N CYZY ]\ ]\U( r+ C
YZY]\N¡-QR *]\N7:^-^l]-40*¢-
4$£+¢-f¤12 mqr,:-4$(¥`+¦§+$¨-©ª«¬­ ®¯Q1 ¬­ f¤1 CYZY Oscillatoria spp.
(®¯*+1( H+S°-04$(r+UqM1,qr ]\
:N. *+er+

. 



/±²³00-ST0+

JK qr !<1´N //- /1, nm!  ]!M1( K µ¶·2¸MR¹º<»(¼r+1 ,+Ni½l#l#3»"0*+1
131   ,  

 !"# $ ORP %&'( pH, ORP, )&*+"#-,-.

 UV-Vis /012345!  ,-* nm 6$%789$:;-.</0& -**/** nm $%789=$>-.?@ A./0&BCA#.

, !D"&.$D#&( )/0E#FD#

ESI-MS $%!  G& HSx =' x ( 1 ,$H) 0 2 +* &I

JDK(.)&L!"# /012345 ESI-MS $%! G&$%78

9 Sx, &*JDK(.)&BCA#/ +MN, O-PQRS.TU5VWX/01,?2-. YZ[\]G&



3$=S.TU5VWX45^_6-5 &$*JDK(.
0

`7*8

Ca#%7899bHA$ nm c7d.TU5VWX-5

a#9b:;<,=e. /1* nm !

/0, nm fVg4D# ))!

,_6C
%78

99b=_6-5 $\.h7ijk>lm$\.?n *9b&8CA.)&opCA#
q@\r YZ[\]G&

 !

fABCA.sC* H,S  S

Dt$\r8 CA#%789 Sx, $\.=EuDK#=S.TU5VW
X_6-5

[H  *.+ mm qv $\.h7ijk>$\.?n $\.Ew

xFCA. D#&"K(.GH[\]IJKL*Q$CA.:;<&r M;<h7ijk>&>-.IJy $NOy$\r P(:;< $.
E?@ A.
Qz{*

%Rlm,SuD#& _6-5 TB51($%S|

`7}~,( %lm,U !$-.V &+. )AWD#(῏῎Qz{X ,YDKwC(D#YZ

Z[\ G&54]$\"K}p(#DD# ))$^,_D- +MN, O-PQR*[`a$r
D#Ybz{%z{cde%z{`fTg hz{il`3j$k,lD@- O-PQR$[(KA,mD#nopq8r
st%quῌvmwz{` x0¡¢£$k,lD@- ESI $%A ¤¥,mD#nopq%mwyl%¢`z{|¦¢£$k,lD@-
Qz{¦q nopq}tz{~ z{W : "O; [\]lm$>-.x§%z{ ¨¤,©ªKLAD# «DK>¬­®$,_D-ῌῑῐ῍Ellis, A. J. and Golding, R. M. (+3/3) : Spectrophotometric determination of the acid dissociation constants of hydrogen sulphide. J. Chem. Soc. Part +, +,1ῌ+-*.
Gun, J., Modestov, A. D., Kamyshny, Jr. A., Ryzkov, D., Gitis, V., Goifman, A., Lev, O., Hultsch,V., Grischek, T. and Worch, E. (,**.) : Electrospray ionization mass spectrometric analysis
of aqueous polysulﬁde solutions. Microchem. Acta, +.0, ,,3ῌ,-1.

¯ °{  +31+ : ±{²³´r#µ , ±{²³´¶[\] ·¸

+0 3*ῌ31.

¹ º +30- : = $>-.z{ ¦ = /012345$»(K ¼½
132

 0*  ,*+*



2- /+-ῌ/+2.
Kleinjan, W.E., de Keizer, A. and Janssen, A. J.H. (,**-) : Biologically produced sulfur particles
and polysulﬁde ions. Top. Curr. Chem. ,-*, +01ῌ+22.
Kleinjan, W.E., de Keizer, A. and Janssen, A. J.H. (,**/) : Equilibrium of the reaction between
dissolved sodium sulﬁde and biologically produced sulfur. Biointerfaces, .-, ,,2ῌ,-1.
Krauskopf, K.B. (+301) : Introduction to Geochemistry, p. ,1*, International ed., McGraw-Hill
Book, New York : Kogakusha, Tokyo.
Ohsawa, S., Kawamura, T., Takamatsu, N. and Yusa, Y. (,**,) : Rayleigh scattering by aqueous colloidal silica as a cause for the blue color of hydrothermal water. J. Volcanol.
Geotherm. Res., ++-, .3ῌ0*.

   ,**- :  !"#$ῌ%&#$'( )*+,'(-./ /. +/ῌ,..
Ohsawa, S., Saito, T., Yoshikawa, S., Mawatari, H., Yamada, M., Amita, K., Takamatsu, N., Sudo,
Y. and Kagiyama, T. (,**3) : Color change of lake water at the active crater lake of Aso
volcano, Yudamari, Japan : is it response to change in water quality induced by volcanic
activity? Limnology, DOI +*.+**1/s+*,*+-**3-*-*.-0.

   ,**- : 01$23456789 !"#$ῌ%&#$'( :;#<= 0. +ῌ+*.
Steudel, R. (,**-) : Inorganic polysulﬁdes Sn, and radical anions Sn῍. Top. Curr. Chem., ,-+,+,1ῌ+/,.
Steudel, R. and Eckert, B. (,**-) : Solid sulfur allotropes. Top. Curr. Chem. ,-*, +ῌ13.

133