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Changes of trihalomethane formation potentials in the tone river
Wat. Res. Vol. 20, No. 8, pp. 999 1003, 1986 Printed in Great Britain
0043-1354/86 $3.00+0.00 Pergamon Journals Ltd
C H A N G E S OF T R I H A L O M E T H A N E F O R M A T I O N POTENTIALS IN THE T O N E RIVER MASAHIRO UCHIYAMA1, YUH NAKAJIMAl a n d YASUMOTO MAGARA 2 IGunma Institute of Public Health, 3-21-19 Iwagami-chyo, Maebashi, Gunma 370 and 2The Institute of Public Health, 4-6-1 Sbiroganedai, Minato-ku, Tokyo 108, Japan
(Received March 1985) Abstract--The changes of trihalomethane formation potentials (THMFPs) in the Tone River were examined. There were clear differences not in THMFPs but in THMFP loading (THMFP x flow rate) between the winter and the summer. The ratio of THMFP loading caused by artificial pollution was estimated. This ratio increased sharply with increases in watershed area and reached about 80% for a watershed area of about 2000 km 2 (with a population density of about 65 persons km-2). Further, two formulas were obtained to estimate the THMFP and THMFP loading of the Tone River in the future.
Key words--trihalomethane formation potential, human activity, artificial pollution, Tone River
INTRODUCTION
collected in glass bottles on days when the river was not affected by precipitation.
It is well k n o w n t h a t t r i h a l o m e t h a n e s ( T H M s ) a n d o t h e r chlorinated organic c o m p o u n d s f o u n d in tap water are formed d u r i n g the c h l o r i n a t i o n process by the reaction between chlorine a n d organic substances, such as h u m i c acids (Rook, 1977; Trussel a n d U m p h r e s , 1978; T a m b o , 1981) a n d o t h e r related c o m p o u n d s (Hasegawa et al., 1983; N o r w o o d et al., 1980) in water. In Japan, there are m a n y water supply systems which use surface water as a source o f drinking water. This water contains n o t only humic materials b u t also o t h e r organic substances, which are the result o f h u m a n activity, t h a t can be T H M precursors (Hasegawa et al., 1983; Sayato et al., 1985; Aizawa et al., 1984). It is necessary to k n o w the t r i h a l o m e t h a n e form a t i o n potentials ( T H M F P s ) of surface water, especially as related to h u m a n activity. In this report, T H M F P s were studied in the surface water of the T o n e River, which is one of the most i m p o r t a n t a n d famous rivers in Japan.
Reagents All reagents used in this study were of analytical grade. The chlorine water was prepared as follows. Concentrated hydrochloric acid was added to calcium hypochlorite and the generated chlorine gas was passed through sulfuric acid, and then adsorbed in distilled water.
EXPERIMENTAL M E T H O D
Experimental sites The experimental sites were chosen from the upper and middle stream regions of the Tone River. Figure 1 shows the sampling stations (Nos 1-17) and the stations to monitor the flow rate (A-N). Half of the river's volume of water is diverted at station C in Fig. 1 for agriculture, drinking water and electric power generation. This water eventually returns to the Tone River at station E. One-quarter of the river's volume of water is also diverted between stations 13 and 14 for use as drinking water. Water sampling The flow rate of the Tone River is low in the winter and high in the summer. Water samples were collected during the winter (from January to March) and the summer (from July to September) of 1983. Water samples were also collected every month at stations 2, 8 and 11 from November 1983 to September 1984. Water samples were 999
Determination of T H M F P The chlorine water was added to sample water in a beaker and the pH was adjusted to 7 + 0.1 with diluted sulfuric acid and/or sodium hydroxide solution. The concentration of the added chlorine was adjusted so that the free residual chlorine concentration was between l and 2 mg l-t at the end of the reaction. Then the water was poured into a stoppered glass bottle and allowed to stand for 24 h at 20°C. The free residual chlorine was measured by the amperometric titration method. After the reaction was finished, an aliquot of water, sodium sulfite solution for removing residual chlorine and phosphoric acid for adjusting the pH below l were added together in a vial and this vial was incubated in a water bath at 25°C for l h. The head space gas in the vial was used to determine the THM concentration. A portion of the head space gas in the vial was injected into the gaschromatograph and the total concentration of chloroform, bromodichloromethane, dibromochloromethane and bromoform were determined. The analysis was conducted on a Shimazu Model 7A gaschromatograph equipped with an electron capture detector. A glass column (o3 mm × 3 m) packed with 20% silicon DC-200 on Chromosorb W (80-I00 mesh) was used for the separation of the components. The column was operated at 100°C and the injection port and the detector temperature were set at 160°C. The carrier gas (nitrogen) flow rate was 45 ml min -1. RESULTS
AND DISCUSSION
The b a c k g r o u n d i n f o r m a t i o n a b o u t the investigation area was examined. The T o n e River is subjected to little industrial pollution from large factories, except for t h a t from two pulp a n d p a p e r m a n u facturing factories on the K a r a s u River in this investigation area. In this investigation area the ratio o f
MASAHIRO UCHIYAMA el al.
1000
%LA
/gotoshino R.
&gatuma R.
\,
Chickens
|e9
g 4. 5.4°//
E g
-
YonogihoroR.
;" / / ' , '~,
o
HiroseR.
KorosuR
~
°° c~ O m
o'
/./
'/: /_:
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7,~'8 Cattle
.O951
1
Oyamo R.
L'~14 WatoroseR , ~
4 2 I,
1
,
2000 Woter shed oreo (km z)
4000
Fig. 3. Relationship between watershed area and number of
domestic animals and BOD loading by domestic animals. Numbers show the sampling stations in Fig. 1.
Fig. 1. Sampling stations in the Tone River. BOD loading from sewage treatment works to the total BOD loading from all facilities is 55% and that from the two pulp and paper manufacturing factories is about 16%, but those from all other kinds of facilities are less than 1% each. Figure 2 shows the relationship between the watershed area (cumulative) and the population (cumulative), and between the watershed area and the BOD loading (cumulative) from factories. In Fig. 2 it is clear that the population and BOD loading from factories increased with watershed area. 12^1~&4
lO^7.o°14
•
/17
r- 0 . 9 8 5 / ~ 1 2
13
._,oo_
_
/ /4:;/Z.o.-
Since it was impossible to get data on the population at stations 15 and 16 or the BOD loading data at station 17, these stations were excluded from Fig. 2. As increases in the population and BOD loading from factories in correlation to increases in watershed area at stations in the tributaries were sharper than that for stations in the Tone River (dotted line in Fig. 2), these stations were excluded when the correlation coefficient was calculated. The number of domestic animals (cattle, pigs and chickens) is shown in Fig. 3 along with its relationship to the watershed area. The presence of other domestic animals are negligible in this investigation area. These results are similar to those for the population and BOD loading from factories shown in Fig. 2. In this figure all the stations from No. l0 to 17 were excluded because of the absence of data. The basic units of BOD loadings from domestic animals were proposed as follows (Japan Society of Water Pollution Research, 1984). Animal
~:
Tc 1-~
_o o
m
5/:' . ~ lO-
.o//3
Yf " /
i
=
/
~
0.1--
Cattle Pigs Chickens
2A"/ 1
/
I I 2000 4000 Woter shed oreo (kin 2)
I 6000
Fig. 2. Relationship between watershed area and population and BOD loading from factories. Numbers show the sampling stations in Fig. 1.
BOD loading (g day ~) 640 200 I0
Using these basic units, BOD loadings from domestic animals were calculated and the results were shown in Fig. 3. These results show that human activity increases sharply as the river flows down in this study area and, therefore the loading of artificial pollution is expected to increase. The T H M F P at each station during the winter and the summer is shown in Fig. 4. This figure shows that the THMFPs increased gradually from the upper
THM formation potential in the river
I - - ]
Winter
MTITI~
Summer
1001
20 A I
,,o. I-
1
2
3
4
5
II 1 8
9
10
11
12
13
14
15
16
17
Sta. No.
Fig. 4. Concentration of THMFP in the Tone River. stream to the middle stream region of the Tone River. However, there are no clear differences in the THMFPs in the winter and the summer. The minimum of T H M F P for both winter and summer was shown at station 2, 8.5 and 8.3/~gl -j, respectively. The maximum of T H M F P for both winter and summer was shown at station 16, 25.3 and 23.1 # g l -~, respectively. The T H M F P at stations 2, 8 and 11 were determined monthly from November 1983 to September 1984 and the T H M F P average at each station was 9.9 13.3 and 24.3pgl -j, respectively. These results were similar to those shown in Fig. 4. Figure 5 shows the relationship between the watershed area and the flow rate. The flow rates for the
winter and the summer are the average rates from January to March 1983 and from July to September 1984, respectively. There is a strong correlation between the watershed area and the flow rate, especially in the summer. As the flow rates are affected by the diversion of water for the many purposes mentioned before, stations 4, 6, 14 and 15 are excluded in Fig. 5. Using the T H M F P data shown in Fig. 4, the T H M F P loading (THMFP x flow rate) at each station was calculated and the results are shown in Fig. 6. This figure shows that the T H M F P loading increases as the fiver progresses downstream and that there are clear differences between the summer and the winter. In this figure T H M F P loadings at stations
600
Summer r =0.993 A
400
c}
~ .,/p ~ 13
+ U_
200
J
Winter /" =0.881
3 +11J
j
1 55°~_
~.1"5 2
,+
°17
.1~"17 2000
8
A J ~
7
~
~
~
~
I
I
I
4000
6000
8000
Water shed area (krn 2 )
Fig. 5. Relationship between watershed area and flow rate. Numbers show the sampling stations in
Fig. 1.
MASAHIRO UCHIYAMA et al.
1002
[--I
Winter
Summer 10lu~
o m 0_ LL ,5-T I'-
1
2
3
4
5
6
9 8 S to. No.
7
10
11
12
13
14
15
16
17
Fig. 6. THMFP loading at each station. 4 and 14 seem to be affected by the diversion of river water. Nos 2, 5, 11 and 17 are stations in the tributaries and the T H M F P loadings at these stations were low compared to that for the Tone River. In Fig. 5, the relationship between the watershed area and the flow rate in the winter is not as strong as that in the summer, especially in the upper stream region. Therefore, in the discussion below, only the summer data will be studied. In Fig. 7 the relationship between the watershed area and T H M F P loading is shown. Since the flow rate is affected by the diversion of water for various purposes, stations 4, 6, 14 and 15 were excluded from this figure. There is a good relation between the watershed area and T H M F P loading. According to the results mentioned above, population, BOD loading from factories and the number of domestic animals sharply increased with increase in the water-
I 0.0
1~/~
-"
8Z
lo
11oo/~/9
-~
.E ~o _
o/17
• • 0.970
u.~rl~.r 1.0
shed area, and therefore, the relationship shown in Fig. 7 may be caused by artificial pollution which increases as human activity increases. To estimate the net effect of artificial pollution on T H M F P loading, T H M F P loading was determined at the stations which were not affected by human activity and is shown in Fig. 7 as a dotted line. X is a station in the upper stream of the Kabura River which is a tributary of the Karasu River. Y and Z are stations in the upper stream of the Katashina River. All of these were determined in July 1984. The T H M F P loading for these three stations were almost entirely unaffected by human activity. The net T H M F P loading through artificial pollution was determined by subtracting the T H M F P loading shown as a dotted line from the T H M F P loading shown as a solid line in Fig. 7. The results are shown in Fig. 8. The ratio of T H M F P loading caused by artificial pollution was about 80% for a watershed area of about 2000 km 2 (with a population of about 130,000). Using the data described above, the future concentration and loading of T H M F P in this study area was estimated. Figure 9 shows the relationship between 100
5
~ 5 .o
~ 50 /
~ /
0.1 I
100
~ /..D"Z
h I
1000 WoTer shed oreo (kin 2 )
I
I'-"
10,000
Fig. 7. Relationship between watershed area and THMFP loading in summer. Numbers show the sampling stations in Fig. 1,
0
I I 2000 4000 Woter shed oreo (kin z)
I 6000
Fig. 8. Changes in the THMFP loading ratio caused by
artificial pollution.
THM formation potential in the river 9 '
~ (1. b-
10_ ~
11 o f 6 ,,,""~o 17
1003
10 tun
2
.5
5--
T I--
30 o5
1
10
[
100
I
1000
Populationdensity(personskm-z)
Fig. 9. Relationship between population density and THMFP. Numbers show the sampling stations in Fig. 1.
population density and T H M F P and this is expressed in the formula below: log Y -- 0.44 + 0.33 log X n=16 r -- 0.921 where X = population density (persons km -2) and Y = T H M F P (#g 1-1). Figure 10 shows the relationship between population density and T H M F P loading and is expressed in the formula below: Y = 5.6 In X - 22.4 n --ll r = 0.928 where X = population density (persons km - : ) and Y = T H M F P loading (gs-~). In Fig. 10, stations l l and 17 did not conform to this relationship. As the population is high and the flow rate is low in these two stations as compared to other stations, stations I 1 and 17 were excluded in calculating the correlation coefficient in Fig. 10. These two formulas will be useful for estimating the T H M F P and its loading in the Tone River in the future. CONCLUSION T H M F P s of surface waters from the upper to the middle stream regions of the Tone River were studied. The conclusions were as follows: (1) There were clear differences not in T H M F P s but in T H M F P loadings in the winter and the summer. (2) There was a strong correlation between watershed area and T H M F P loading. (3) The T H M F P loading ratio caused by artificial pollution was sharply increased and reached about 80% for a watershed area of about 2000 km 2 (with a population density of about 65 persons kin-2).
I I--
10
o2 l ~ i I 1 O0 1000 Populationdensity(personskm-z)
Fig. 10. Relationship between population density and THMFP loading. Numbers show the sampling stations in Fig. 1. (4) There was a strong correlation between population density and T H M F P and T H M F P loading. F r o m these relationships, two useful formulas were induced to estimate the T H M F P and the T H M F P loading of the Tone River in the future. Acknowledgements--The authors express thanks to Dr A. Ujiie, the director of Gunma Institute of Public Health, for useful advice. This work was done under a project entitled "Control of organochloro compounds precursor in natural water bodies" under the auspice of the Sanitary Engineering Committee, the Japan Society of Civil Engineers. REFERENCES
Aizawa T., Hasegawa K., Adachi S. and Magara Y. (1984) Characteristics of the formation of total organic chlorides from organic compounds by aqueous chlorination. Jap. J. Wat. Pollut. Res. 7, 108-117. Hasegawa K., Aizawa T., Naito S. and Magara Y. (1983) Characteristics for the formation of chloroform from organic compounds by aqeous chlorination, Jap. J. Wat. Pollut. Res. 6, 151-160. Japan Society on Water Pollution Research (1984) Manual of Water Quality Survey o f Lake and Reservoir (Koshyo kankyo chosa shishin--Japanese edition). JSWPR, Tokyo. Norwood D. L., Johnson J. D. and Christman R. F. (1980) Reaction of chlorine with selected aromatic models of aquatic humic material. Envir. Sci. Technol. 14, 187 190. Rook J. J. (1977) Chlorination reactions of humic acid in natural water. Envir. Sci. Technol. 11, 478-482. Sayato Y., Nakamuro K., Iriguchi M., Sana H. and Harada T. (1985) Occurrence and behavior of trihalomethanes and total organic halides precursors along the Tsurumi River. Jap. J. Wat. Pollut. Res. 8, 110~116. Tambo N. (1981) Meanings of trihalomethane problem. J. Wat. Waste (Yosui to Haisui) 22, 915-922. Trussel R. R. and Umphres M. D. (1978) The formation of trihalomethanes. J. Am. Wat. Wks Ass. 70, 604-612.
0043-1354/86 $3.00+0.00 Pergamon Journals Ltd
C H A N G E S OF T R I H A L O M E T H A N E F O R M A T I O N POTENTIALS IN THE T O N E RIVER MASAHIRO UCHIYAMA1, YUH NAKAJIMAl a n d YASUMOTO MAGARA 2 IGunma Institute of Public Health, 3-21-19 Iwagami-chyo, Maebashi, Gunma 370 and 2The Institute of Public Health, 4-6-1 Sbiroganedai, Minato-ku, Tokyo 108, Japan
(Received March 1985) Abstract--The changes of trihalomethane formation potentials (THMFPs) in the Tone River were examined. There were clear differences not in THMFPs but in THMFP loading (THMFP x flow rate) between the winter and the summer. The ratio of THMFP loading caused by artificial pollution was estimated. This ratio increased sharply with increases in watershed area and reached about 80% for a watershed area of about 2000 km 2 (with a population density of about 65 persons km-2). Further, two formulas were obtained to estimate the THMFP and THMFP loading of the Tone River in the future.
Key words--trihalomethane formation potential, human activity, artificial pollution, Tone River
INTRODUCTION
collected in glass bottles on days when the river was not affected by precipitation.
It is well k n o w n t h a t t r i h a l o m e t h a n e s ( T H M s ) a n d o t h e r chlorinated organic c o m p o u n d s f o u n d in tap water are formed d u r i n g the c h l o r i n a t i o n process by the reaction between chlorine a n d organic substances, such as h u m i c acids (Rook, 1977; Trussel a n d U m p h r e s , 1978; T a m b o , 1981) a n d o t h e r related c o m p o u n d s (Hasegawa et al., 1983; N o r w o o d et al., 1980) in water. In Japan, there are m a n y water supply systems which use surface water as a source o f drinking water. This water contains n o t only humic materials b u t also o t h e r organic substances, which are the result o f h u m a n activity, t h a t can be T H M precursors (Hasegawa et al., 1983; Sayato et al., 1985; Aizawa et al., 1984). It is necessary to k n o w the t r i h a l o m e t h a n e form a t i o n potentials ( T H M F P s ) of surface water, especially as related to h u m a n activity. In this report, T H M F P s were studied in the surface water of the T o n e River, which is one of the most i m p o r t a n t a n d famous rivers in Japan.
Reagents All reagents used in this study were of analytical grade. The chlorine water was prepared as follows. Concentrated hydrochloric acid was added to calcium hypochlorite and the generated chlorine gas was passed through sulfuric acid, and then adsorbed in distilled water.
EXPERIMENTAL M E T H O D
Experimental sites The experimental sites were chosen from the upper and middle stream regions of the Tone River. Figure 1 shows the sampling stations (Nos 1-17) and the stations to monitor the flow rate (A-N). Half of the river's volume of water is diverted at station C in Fig. 1 for agriculture, drinking water and electric power generation. This water eventually returns to the Tone River at station E. One-quarter of the river's volume of water is also diverted between stations 13 and 14 for use as drinking water. Water sampling The flow rate of the Tone River is low in the winter and high in the summer. Water samples were collected during the winter (from January to March) and the summer (from July to September) of 1983. Water samples were also collected every month at stations 2, 8 and 11 from November 1983 to September 1984. Water samples were 999
Determination of T H M F P The chlorine water was added to sample water in a beaker and the pH was adjusted to 7 + 0.1 with diluted sulfuric acid and/or sodium hydroxide solution. The concentration of the added chlorine was adjusted so that the free residual chlorine concentration was between l and 2 mg l-t at the end of the reaction. Then the water was poured into a stoppered glass bottle and allowed to stand for 24 h at 20°C. The free residual chlorine was measured by the amperometric titration method. After the reaction was finished, an aliquot of water, sodium sulfite solution for removing residual chlorine and phosphoric acid for adjusting the pH below l were added together in a vial and this vial was incubated in a water bath at 25°C for l h. The head space gas in the vial was used to determine the THM concentration. A portion of the head space gas in the vial was injected into the gaschromatograph and the total concentration of chloroform, bromodichloromethane, dibromochloromethane and bromoform were determined. The analysis was conducted on a Shimazu Model 7A gaschromatograph equipped with an electron capture detector. A glass column (o3 mm × 3 m) packed with 20% silicon DC-200 on Chromosorb W (80-I00 mesh) was used for the separation of the components. The column was operated at 100°C and the injection port and the detector temperature were set at 160°C. The carrier gas (nitrogen) flow rate was 45 ml min -1. RESULTS
AND DISCUSSION
The b a c k g r o u n d i n f o r m a t i o n a b o u t the investigation area was examined. The T o n e River is subjected to little industrial pollution from large factories, except for t h a t from two pulp a n d p a p e r m a n u facturing factories on the K a r a s u River in this investigation area. In this investigation area the ratio o f
MASAHIRO UCHIYAMA el al.
1000
%LA
/gotoshino R.
&gatuma R.
\,
Chickens
|e9
g 4. 5.4°//
E g
-
YonogihoroR.
;" / / ' , '~,
o
HiroseR.
KorosuR
~
°° c~ O m
o'
/./
'/: /_:
\ )
/T /
/4 / 50/o/"
7,~'8 Cattle
.O951
1
Oyamo R.
L'~14 WatoroseR , ~
4 2 I,
1
,
2000 Woter shed oreo (km z)
4000
Fig. 3. Relationship between watershed area and number of
domestic animals and BOD loading by domestic animals. Numbers show the sampling stations in Fig. 1.
Fig. 1. Sampling stations in the Tone River. BOD loading from sewage treatment works to the total BOD loading from all facilities is 55% and that from the two pulp and paper manufacturing factories is about 16%, but those from all other kinds of facilities are less than 1% each. Figure 2 shows the relationship between the watershed area (cumulative) and the population (cumulative), and between the watershed area and the BOD loading (cumulative) from factories. In Fig. 2 it is clear that the population and BOD loading from factories increased with watershed area. 12^1~&4
lO^7.o°14
•
/17
r- 0 . 9 8 5 / ~ 1 2
13
._,oo_
_
/ /4:;/Z.o.-
Since it was impossible to get data on the population at stations 15 and 16 or the BOD loading data at station 17, these stations were excluded from Fig. 2. As increases in the population and BOD loading from factories in correlation to increases in watershed area at stations in the tributaries were sharper than that for stations in the Tone River (dotted line in Fig. 2), these stations were excluded when the correlation coefficient was calculated. The number of domestic animals (cattle, pigs and chickens) is shown in Fig. 3 along with its relationship to the watershed area. The presence of other domestic animals are negligible in this investigation area. These results are similar to those for the population and BOD loading from factories shown in Fig. 2. In this figure all the stations from No. l0 to 17 were excluded because of the absence of data. The basic units of BOD loadings from domestic animals were proposed as follows (Japan Society of Water Pollution Research, 1984). Animal
~:
Tc 1-~
_o o
m
5/:' . ~ lO-
.o//3
Yf " /
i
=
/
~
0.1--
Cattle Pigs Chickens
2A"/ 1
/
I I 2000 4000 Woter shed oreo (kin 2)
I 6000
Fig. 2. Relationship between watershed area and population and BOD loading from factories. Numbers show the sampling stations in Fig. 1.
BOD loading (g day ~) 640 200 I0
Using these basic units, BOD loadings from domestic animals were calculated and the results were shown in Fig. 3. These results show that human activity increases sharply as the river flows down in this study area and, therefore the loading of artificial pollution is expected to increase. The T H M F P at each station during the winter and the summer is shown in Fig. 4. This figure shows that the THMFPs increased gradually from the upper
THM formation potential in the river
I - - ]
Winter
MTITI~
Summer
1001
20 A I
,,o. I-
1
2
3
4
5
II 1 8
9
10
11
12
13
14
15
16
17
Sta. No.
Fig. 4. Concentration of THMFP in the Tone River. stream to the middle stream region of the Tone River. However, there are no clear differences in the THMFPs in the winter and the summer. The minimum of T H M F P for both winter and summer was shown at station 2, 8.5 and 8.3/~gl -j, respectively. The maximum of T H M F P for both winter and summer was shown at station 16, 25.3 and 23.1 # g l -~, respectively. The T H M F P at stations 2, 8 and 11 were determined monthly from November 1983 to September 1984 and the T H M F P average at each station was 9.9 13.3 and 24.3pgl -j, respectively. These results were similar to those shown in Fig. 4. Figure 5 shows the relationship between the watershed area and the flow rate. The flow rates for the
winter and the summer are the average rates from January to March 1983 and from July to September 1984, respectively. There is a strong correlation between the watershed area and the flow rate, especially in the summer. As the flow rates are affected by the diversion of water for the many purposes mentioned before, stations 4, 6, 14 and 15 are excluded in Fig. 5. Using the T H M F P data shown in Fig. 4, the T H M F P loading (THMFP x flow rate) at each station was calculated and the results are shown in Fig. 6. This figure shows that the T H M F P loading increases as the fiver progresses downstream and that there are clear differences between the summer and the winter. In this figure T H M F P loadings at stations
600
Summer r =0.993 A
400
c}
~ .,/p ~ 13
+ U_
200
J
Winter /" =0.881
3 +11J
j
1 55°~_
~.1"5 2
,+
°17
.1~"17 2000
8
A J ~
7
~
~
~
~
I
I
I
4000
6000
8000
Water shed area (krn 2 )
Fig. 5. Relationship between watershed area and flow rate. Numbers show the sampling stations in
Fig. 1.
MASAHIRO UCHIYAMA et al.
1002
[--I
Winter
Summer 10lu~
o m 0_ LL ,5-T I'-
1
2
3
4
5
6
9 8 S to. No.
7
10
11
12
13
14
15
16
17
Fig. 6. THMFP loading at each station. 4 and 14 seem to be affected by the diversion of river water. Nos 2, 5, 11 and 17 are stations in the tributaries and the T H M F P loadings at these stations were low compared to that for the Tone River. In Fig. 5, the relationship between the watershed area and the flow rate in the winter is not as strong as that in the summer, especially in the upper stream region. Therefore, in the discussion below, only the summer data will be studied. In Fig. 7 the relationship between the watershed area and T H M F P loading is shown. Since the flow rate is affected by the diversion of water for various purposes, stations 4, 6, 14 and 15 were excluded from this figure. There is a good relation between the watershed area and T H M F P loading. According to the results mentioned above, population, BOD loading from factories and the number of domestic animals sharply increased with increase in the water-
I 0.0
1~/~
-"
8Z
lo
11oo/~/9
-~
.E ~o _
o/17
• • 0.970
u.~rl~.r 1.0
shed area, and therefore, the relationship shown in Fig. 7 may be caused by artificial pollution which increases as human activity increases. To estimate the net effect of artificial pollution on T H M F P loading, T H M F P loading was determined at the stations which were not affected by human activity and is shown in Fig. 7 as a dotted line. X is a station in the upper stream of the Kabura River which is a tributary of the Karasu River. Y and Z are stations in the upper stream of the Katashina River. All of these were determined in July 1984. The T H M F P loading for these three stations were almost entirely unaffected by human activity. The net T H M F P loading through artificial pollution was determined by subtracting the T H M F P loading shown as a dotted line from the T H M F P loading shown as a solid line in Fig. 7. The results are shown in Fig. 8. The ratio of T H M F P loading caused by artificial pollution was about 80% for a watershed area of about 2000 km 2 (with a population of about 130,000). Using the data described above, the future concentration and loading of T H M F P in this study area was estimated. Figure 9 shows the relationship between 100
5
~ 5 .o
~ 50 /
~ /
0.1 I
100
~ /..D"Z
h I
1000 WoTer shed oreo (kin 2 )
I
I'-"
10,000
Fig. 7. Relationship between watershed area and THMFP loading in summer. Numbers show the sampling stations in Fig. 1,
0
I I 2000 4000 Woter shed oreo (kin z)
I 6000
Fig. 8. Changes in the THMFP loading ratio caused by
artificial pollution.
THM formation potential in the river 9 '
~ (1. b-
10_ ~
11 o f 6 ,,,""~o 17
1003
10 tun
2
.5
5--
T I--
30 o5
1
10
[
100
I
1000
Populationdensity(personskm-z)
Fig. 9. Relationship between population density and THMFP. Numbers show the sampling stations in Fig. 1.
population density and T H M F P and this is expressed in the formula below: log Y -- 0.44 + 0.33 log X n=16 r -- 0.921 where X = population density (persons km -2) and Y = T H M F P (#g 1-1). Figure 10 shows the relationship between population density and T H M F P loading and is expressed in the formula below: Y = 5.6 In X - 22.4 n --ll r = 0.928 where X = population density (persons km - : ) and Y = T H M F P loading (gs-~). In Fig. 10, stations l l and 17 did not conform to this relationship. As the population is high and the flow rate is low in these two stations as compared to other stations, stations I 1 and 17 were excluded in calculating the correlation coefficient in Fig. 10. These two formulas will be useful for estimating the T H M F P and its loading in the Tone River in the future. CONCLUSION T H M F P s of surface waters from the upper to the middle stream regions of the Tone River were studied. The conclusions were as follows: (1) There were clear differences not in T H M F P s but in T H M F P loadings in the winter and the summer. (2) There was a strong correlation between watershed area and T H M F P loading. (3) The T H M F P loading ratio caused by artificial pollution was sharply increased and reached about 80% for a watershed area of about 2000 km 2 (with a population density of about 65 persons kin-2).
I I--
10
o2 l ~ i I 1 O0 1000 Populationdensity(personskm-z)
Fig. 10. Relationship between population density and THMFP loading. Numbers show the sampling stations in Fig. 1. (4) There was a strong correlation between population density and T H M F P and T H M F P loading. F r o m these relationships, two useful formulas were induced to estimate the T H M F P and the T H M F P loading of the Tone River in the future. Acknowledgements--The authors express thanks to Dr A. Ujiie, the director of Gunma Institute of Public Health, for useful advice. This work was done under a project entitled "Control of organochloro compounds precursor in natural water bodies" under the auspice of the Sanitary Engineering Committee, the Japan Society of Civil Engineers. REFERENCES
Aizawa T., Hasegawa K., Adachi S. and Magara Y. (1984) Characteristics of the formation of total organic chlorides from organic compounds by aqueous chlorination. Jap. J. Wat. Pollut. Res. 7, 108-117. Hasegawa K., Aizawa T., Naito S. and Magara Y. (1983) Characteristics for the formation of chloroform from organic compounds by aqeous chlorination, Jap. J. Wat. Pollut. Res. 6, 151-160. Japan Society on Water Pollution Research (1984) Manual of Water Quality Survey o f Lake and Reservoir (Koshyo kankyo chosa shishin--Japanese edition). JSWPR, Tokyo. Norwood D. L., Johnson J. D. and Christman R. F. (1980) Reaction of chlorine with selected aromatic models of aquatic humic material. Envir. Sci. Technol. 14, 187 190. Rook J. J. (1977) Chlorination reactions of humic acid in natural water. Envir. Sci. Technol. 11, 478-482. Sayato Y., Nakamuro K., Iriguchi M., Sana H. and Harada T. (1985) Occurrence and behavior of trihalomethanes and total organic halides precursors along the Tsurumi River. Jap. J. Wat. Pollut. Res. 8, 110~116. Tambo N. (1981) Meanings of trihalomethane problem. J. Wat. Waste (Yosui to Haisui) 22, 915-922. Trussel R. R. and Umphres M. D. (1978) The formation of trihalomethanes. J. Am. Wat. Wks Ass. 70, 604-612.