Journal of Environmental Protection, 2011, 2, 204-212
doi:10.4236/jep.2011.22024 Published Online April 2011 (http://www.SciRP.org/journal/jep)
Influence of Biogeochemical Qualities of Shizuoka
Water on the Degradation of PVC Shower Hose
Mst. Shamsun Nahar*, Jing Zhang, Shogo Nakamura
Department of Environmental Biology and Chemistry, Graduate School of Science and Engineering, University of Toyama, Gofuku,
Toyama, Japan.
Received December 25th, 2010; revised February 1st, 2011; accepted March 6th, 2011.
ABSTRACT
Recently, it has been report of polyvinyl chloride (PVC) shower hoses becoming hard and b rittle th roughou t th e eastern
and middle portion of Shizuoka Prefecture, Japan. No reason has been identified for this phenomenon. The affected
cities are located at the paper industries area. We have collected the stiffed hoses attached to shower faucets and ex-
amined them for chemica l changes. In addition, we have analyzed the water qua lity of 11 affected cities in Shizuoka in
an attempt to establish a probable bio-physico-chemical chain reaction that could cause such hose degradation. Ac-
cording to elemental analysis, oxygen-containing carbon-based plasticizers may leach out of the hose. As a result, the
hoses lost flexibility after one year o f use in Shizuoka. The organic nu trient (1,4-dioxane) was identified b y GC-MS and
the utmost number of the heterotroph ic bacteria ha s been detected by PCR-DGGE in the shower water o f Shizu o ka. The
study concludes tha t the plasticizer disappeared fro m the stiffed hose and the special characteristics of water in Shizu-
oka, consisting of organic nutrients, can be used for heterotrophic bacterial growth as a energy source at the shower
water temperature, which allows promp t utilization of the plas ticizer by increasing abundan t bacteria, causing the brit-
tleness of the PVC hose.
Keywords: Shizuoka Water, Plasticized PVC Hose, Bacterialnutrient, PCR-DGGE, Paper Industries
1. Introduction
In a study to identify the bio-chemical process causing
damage to PVC shower hoses, the structure and material
content of the hoses were thoroughly analyzed. This
study took place in eastern Shizuoka Prefecture, Japan,
and included an investigation of the domestic and natural
water sources. Polyvinyl chloride (PVC) is a commercial,
inexpensive material used for water pipes, and it is com-
patible with plasticizers, such as diisononyl phthalate
(DINP) and tri-octyle trimellitate (TOTM), which make
it flexible [1]. However, the microbial and chemical
qualities of water passing through polyethylene pipes can
not only affect the plastic materials but also cause the
migration of various compounds, as plasticizer compounds
from PVC tubes have been reported [2-5]. Therefore,
plasticized polyvinyl chloride can be attacked by micro-
organisms [6]. The microorganisms can use the plasti-
cizer as a carbon source; moreover, a favorable growth
condition, such as water, temperature, and nutrients,
promotes microbial growth [7]. In the last several years,
bacterial community succession related to polar cyclic
ether (1,4-dioxane and 1,4-dioxin) exposure has been
investigated; all these studies have provided valuable
information on the potential for biodegradation of polar
cyclic ether among various microorganisms [8-12]. Very
recently, the bacterial nutrients 1,4-dioxane has emerged
as an important water contaminant elsewhere [13-15].
Microbial growth is directly related to the supply of nu-
trients [16-18]. Le Chevallier et al. [19] indicated that
organic carbon has a significant influence on the growth
of bacteria in distributed water. In the last several years,
however, 1,4-dioxane biodegradation has been reported
for pure [20,21] and mixed cultures of bacteria [22,23] as
well as for a fungal isolate [24]. Moreover, the simulta-
neous effect of the pH and temperature on the growth of
heterotrophic bacteria has been determined [16]. It has
been shown that it is the plasticizer, and not the plastic
itself, that is attacked by the microorganisms [2, 25-28];
the observed embrittlement of the plastic composition
was thus explained by the progressive disappearance of
the plasticizer. Therefore, it was of interest to investigate
this degradation further with a view to elucidating its
mechanism with respect to the relationship between the

Influence of Biogeochemical Qualities of Shizuoka Water on the Degradation of PVC Shower Hose205
amount of organic nutrients and the temperature required
to support bacterial growth. In Shizuoka, shower hoses
are losing flexibility and becoming hard after just one
year of use. As part of a regional study on the mechanism
behind the damage to PVC shower hoses in Shizuoka
(Japan), damaged hoses and water samples of raw,
treated, and distributed water were collected from 34
stations from eastern Shizuoka to identify the reason for
the damage. Eastern Shizuoka is one of the major indus-
trial centers of Shizuoka Prefecture, and Fuji City has
hosted numerous chemical plants, life science industries,
and 85 highly developed paper factories including Nip-
pon Paper Industries and the Oji Paper Company, since
the Meiji period. In paper manufacturing, large amounts
of polar cyclic ether (1,4-dioxane and 1,4-dioxin) is
widely used as an industrial solvent and a solvent stabi-
lizer. Likewise, organic pollutants from the paper-recy-
cling process have been identified and quantified from
the water discharge area in Fuji City [29-31]. However,
the effect of these large contaminant plumes threatening
domestic water supplies that are near the original release
sites has not been investigated. As this new damage was
only found on the inside of shower hoses in Shizuoka, we
have selected the following parameters for investigation:
1) chemical changes in damaged hoses; 2) Shizuoka wa-
ter quality (physicochemical and microbial); and 3)
shower water temperature. However, we are the first in-
vestigator, requested by hose manufacturing company to
investigate this new intricate damage problem and it can
be assumed that environmental factors are of great im-
portance in determining the mechanism of damage. This
investigation research is based on the assessment carried
out by analytical and material characterization methods.
The purposes of this study are to identify the unknown
chemical changes in damaged shower hoses and clarify
the effect of water fluid on the damage mechanism on the
basis of the quality of Shizuoka water.
2. Materials and Methods
2.1. Study Area Description
Shizuoka’s boundaries are 155 km from east to west and
118 km from north to south (Figure 1(a)), which is lo-
cated on the coast of Suruga Bay in the Pacific Ocean,
has one of the leading paper industries in Japan and has
the full range of Japanese geographical oceanic climates.
We investigated the quality of water from 34 stations in
11 affected cities (1. Suntou-gunSt(1-3), 2. GotenbaSt(4-6), 3a.
SusosnoSt(7-8), 3b. Suntou-gun (Susosno), 5. Mishi-
maSt(9-13), 7. Atami, 8. NumazuSt(14-15), 19) FujiSt(16-20), 20)
FujinomiyaSt(21-31), x) FujiyoshidaSt(32-33), 24. A. Sidagun,
and 24.b. Shizuoka-shi) from eastern Shizuoka located
between latitudes 35˚07'0.9"N and 35˚28'15.4"N and lon-
gitudes 138˚33'44.0"E and 138˚59'10.9"E (Figure 1(b)).
In Figure 1(a), affected cities are marked by black circle
and red marker denotes the paper mills locations.
2.2. Materials and Experimental Techniques
All chemicals and standards were of the highest purity
grade, and MilliQ water (resistivity 18.2 M) was used
during the experiments. The internal standard and VOC
mixes (containing 23 VOCs) for the calibration of
GC-MS, major ion standard solution were purchased
from Kanto Co., Ltd. (Japan). Figure 2(a) shows the
location of the damage to the hose inside the shower sys-
tem. The bacteria formation was studied in laboratory on
new PVC hose surface at temperatures at 25˚C and 37˚C
(Figure 2(b)). The water flow was controlled by peristal-
tic pump. The reservoir (flat bottom volumetric flux) of
this system was filled twice a week with tap water origi-
nating from Shizuoka water plant. Similar physical
changes were observed in the laboratory-analyzed hoses
(Figure 2(b)) as the damaged shower hoses (Figure 2(a))
collected from Shizuoka prefecture. The high-tempera-
ture area was stiffer than the lower-temperature area of
the analyzed PVC hoses (Figure 2(b)). However, to ob-
serve the physical and chemical changes in used shower
Figure 1. Surveyed area (Shizuoka, Japan): affected cities
(O), (a) paper mills(●), (b) sampling station (●).
(a) (b)
Figure 2. Shower hose (in Shizuoka) and (b) an apparatus
setup for hose analysis.

Influence of Biogeochemical Qualities of Shizuoka Water on the Degradation of PVC Shower Hose
206
hoses, a continuous hot and cold water flow system
through new hoses was designed in our laboratory (Fig-
ure 2(b)).
We measured the elements and their concentration in
PVC hoses using a Wavelength-Dispersive X-ray fluo-
rescence (WD-XRF) (PW 2404R, PHILIPS) machine.
The carbon (C) and hydrogen (H) weight % were deter-
mined with a CHNS analyzer (VarioMICRO-cube TYU).
The surface characteristics were analyzed using
FE-SEM (JEOL, FE-SEM 6700F). The elemental com-
position can be determined with an energy-dispersive
X-ray spectrometer (EDS, JED-2200). The elements O,
C, and Cl were determined in this work. Acceleration
voltage of 15 kV and a beam current of 6  10−8 A were
used in the FESEM / EDS analyses.
Major ions were determined by 761-compact ion
chromatography (IC). Cation analysis was performed
using a TSK gel IC cation 1/2 HR column (No. J902830),
a sample flow rate of 0.8 mL/min and electrical conduc-
tivity (EC) 487.86 S/cm. Anion analysis was performed
using a Shodex IC SI-90 4E column (No. J007842),
sample flow rate of 1.3 mL/min and EC: 13.76 S/cm.
Injection volumes were 20 L for both anion and cation
analysis. GC–MS analysis was conducted with a Shima-
dzu (Japan) model GC-17A gas chromatograph coupled
to a Shimadzu model GCMS-QP5050 mass spectrometer.
The instrument was operated in the electron ionization
mode at 70 eV, an ion source temperature of 240˚C, a
mass range of 10 to 900, scan range of 60 - 600 m/z (1
sec interval), sensitivity 100 pg, maximum scanning
speed 6.750 u/ sec (for single scan).
Bacterial growth was enriched on PVC hose surface,
exposed to hot water about one month and the total bac-
terial DNA concentration was measured by using PCR
method. For the determining of DNA concentration of
bacterial DNA-containing PVC hose, we performed
some steps were as follows: the scissor was washed using
C2H5OH, then the analyzed hose (3 cm long) was washed
with C2H5OH, cut the hose by sterilized scissor into 1 cm
pieces (3/3 = 1 cm), insert the 1 cm long hose into 15 ml
centrifugal tube, then DNA extraction is done by phenol
– chloroform method.
Bacterial community responsible for shower hose
degradation can be detected from shower water by the
PCR-DGGE method. The media were a standard medium
(Nissui) and an agar medium (Difco). The culture condi-
tions were as follows: temperature, 20˚C; incubation, 2
days; sample volume, 10 - 20 l. Bacterial cells were
collected from 100 mL of shower water samples by fil-
tration using filters with a pore size of 0.2 m. After fil-
tration, the filters were transferred into 15 mL centrifuge
tubes and stored at –20˚C until DNA extraction. DNA
extractions were performed with the phenol-chloroform
method [32]. The filtered samples were subjected to
freeze and thaw cycles three times. One mL of lysozyme
(Worthington Biochemical Co.; 10 mg/mL in Tris-HCl,
pH 8.0) was then added, and the samples were mixed and
incubated at room temperature. After 5 min of incubation,
1 mL of an NE buffer (0.15 M NaCl, 0.1 M EDTA), 50
L of RNase (Sigma-Aldrich Co.; 20 mg/mL), and 50 L
of 20% SDS were added, and incubation proceeded at 60
0C for 10 min. Then, 50 L of proteinase K (Takara Bio,
Inc.; 20 mg/mL) was added and incubated at 50˚C for 5
min. After centrifugation at 3500 rpm for 5 min at room
temperature, the supernatants were extracted with an
equal volume of TE-saturated phenol (Nippon Gene Co.),
phenol-chloroformisoamylalcohol (25:24:1), and chloro-
form. The aqueous phase was finally precipitated with
0.7 volume isopropanol by centrifugation at 13,000 rpm
for 15 min at 4˚C, and the pellet was washed with 70%
ethanol and resuspended in 200 L of the TE buffer (10
mM Tris-HCl [pH 8.0], 1 mM EDTA). Bacterial cells in
the 100-lL liquid culture medium were collected by cen-
trifugation, and DNA extraction was performed by the
above procedure for the filtered seawater samples. The
variable V3 region of the bacterial 16S rDNA was ampli-
fied by PCR with primers 341F (5-CCTACGGGAGGC
AGCAG-3) and 518R (5-ATTACCGCGGCT GCTGG-
3) [32]. A 40-bp GC clamp (5-CGCCCGCCGCGCCC
CGCGCCCGTCCCGCCGCCCCCGCCCG-3) was added
to the 5 end of the 341F primer. The amplification reac-
tion was performed in a 40-L reaction mixture contain-
ing a 1  PCR buffer, 0.5 M for each primer, 0.2 mM
dNTPs, 1 U of Takara Ex Taq HS (Takara Bio, Inc.), and
2 L of a DNA template solution. PCR amplification was
carried out by initial denaturation at 94˚C for 3 min fol-
lowed by 35 cycles at 94˚C for 1 min, 60˚C for 1 min,
and 72˚C for 1 min and final extension at 72˚C for 3 min
and then held at 15˚C. The PCR products were analyzed
for quality and concentration by electrophoresis on 2%
(w/v) agarose gels stained with ethidium bromide. DGGE
was performed with a D-code system (Bio-Rad Labora-
tories, Inc.) in accordance with the manufacturer’s in-
structions. The PCR products were loaded onto 8% (w/v)
polyacrylamide gels in a 0.5  TAE buffer diluted from
50  TAE buffer (2 M Tris base, 2 M glacial acetic acid,
and 50 mM EDTA). The polyacrylamide gels were made
with a denaturing gradient ranging from 25% to 65%
(where a 100% denaturant contains 7 M urea and 40%
formamide). Electrophoresis was carried out at 60˚C for
12 h at 70 V, after which the gels were stained with
ethidium bromide and photographed on a UV transillu-
mination table with a Multi-Doc-it system (UVP, Inc.).
3. Results and Discussion
We developed a plan to research the brittleness in PVC

Influence of Biogeochemical Qualities of Shizuoka Water on the Degradation of PVC Shower Hose
207
hoses; first, we characterized the damaged hoses col-
lected from Shizuoka Prefecture using different analysis
methods and confirmed any chemical differences be-
tween these hoses and new ones. Then, to clarify any
chemical and physical changes to the hoses that took
place during their use in Shizuoka, a laboratory study
was undertaken to investigate the hardness of the PVC.
Finally, we studied the effects of a microbial process in
conjunction with the physicochemical properties of Shi-
zuoka water on the degradation of the hose.
3.1. Compare the Elemental Concentration
The element (C, H, Cl, O, Ca, Zn, Si, and Mg) compo
sitions of damaged and new hoses were obtained by
X-ray fluorescence using a Wavelength-Dispersive XRF
spectrometer and CHNS. The main elemental composi-
tions are C, H, Cl, and O with lesser amounts of Zn, Al,
Si, and Mg. Carbon and hydrogen were measured with a
CHNS analyzer. Shower hoses are made of PVC
(56.53%), plasticizer (DINP: 39.5%), and other materials,
such as epoxidized soya bean oil (1.7%), a stabilizer
(1.13%), a lubricant (0.2%), pigment (0.45%), and a
filler. In the carbon concentration is less in damaged than
in new hoses. As illustrated, the weight percent of oxy-
gen decreased after the degradation of the PVC hose,
whereas the chloride concentration appeared to increase.
The reduction in oxygen is equivalent to the increase in
the amount of chloride for the total sum of the elements
of damaged hoses using the WD-XRF machine. Conse-
quently, the chloride concentration of the damaged hose
had not changed, which indicates that the original struc-
ture of the PVC hose had not been modified by the water
quality. The carbon and oxygen concentrations had de-
creased in the used hose, which indicates that the plasti-
cizer had leached out of the hose and the hose had be-
come hardened. This is because the plasticizer, which
contains oxygen and carbon, softens the PVC hose. The
exposed parts of the hose in hot water became hardened,
whereas the unexposed parts in hot water were almost
unaffected (Figure 2(b)). The carbon and oxygen con-
centrations were lower in the parts exposed to hot water
(B < C) than in those exposed to water at room tempera-
ture (Figure 2(b)), which indicates the importance of
temperature relative to the stiffness of the PVC hose.
3.2. FE-SEM Mapping / EDS
FE-SEM is a promising tool for the visualization of
structures and phenomena of surface characteristics. FE-
SEM/EDS was used to obtain information that would
explain the stiffness and elemental changes in structure
occurring in PVC hoses. Figure 3(a) and Figure 3(b)
show the FE-SEM images and chloride (Cl) mapping of
new and used PVC hose surfaces respectively. According
to the EDS peak count (Figure 3(a) and Figure 3(b));
the oxygen and carbon counts for stiffed damaged hoses
were lower than those in new ones. It is possible that
carbon and oxygen in the compound plasticizer in the
PVC hose disappear, and, as a result, the level of those
materials is lower in damaged PVC hoses; in addition,
oxygen is a structural element in the plasticizer mole-
cules in PVC hoses.
3.3. Bacterial DNA Concentrations
Bacterial DNA concentration on PVC hose surface was
measured by PCR method and the quantified DNA con-
centration was different for the different surface of the
PVC hose exposed to hot (37˚C, B surface) and cold
(25˚C surface) water in laboratory-analyzed hose (Figure
2(b)). The highest DNA concentration was found in sam-
ple B. The DNA concentration was different in the sam-
ples analyzed in the laboratory: B (7.4 ng/μg) > C (2.2
ng/μg). Here, the B side was made to contact hot water,
but not the C side (Figure 2(b)), and, after one month of
continuous water flow through the PVC hose, the B area
became harder than the C area, and the oxygen concen-
tration also decreased inside sample B more than it did in
(a) (b)
Figure 3. EDS Peak: (a) new hose; (b) stiffed hose.

Influence of Biogeochemical Qualities of Shizuoka Water on the Degradation of PVC Shower Hose
208
sample C and a new hose. The highest DNA concentra-
tion, 7.4 ng/μg(B), was detected on PVC hose surface
after 4 weeks’ exposure to hot water (37˚C). A.W. Mayo
and T. Noike [16] recommended the incubation tem-
perature of 35˚C (72 h) with pH 7.0, for heterotrophic
bacteria [16].
According to bacterial analysis, four types of bacteria
were detected in shower water with their association
number: 1) Pseudomonas fluorescens, 2) Pseudomonas
sp., 3) Alpha proteobacterium SKA54 (Citreimonas sp.),
and 4) Alpha proteobacterium IMCC10422 (Candidatus
Pelagibacter ubique) (Table 1). However, Citreimonas
sp. and Candidatus Pelagibacter ubique were not possi-
ble to culture, although their concentration was higher in
Shizuoka tap water samples. However, the lower con-
centrations of Pseudomonas fluorescens and Pseudomo-
nas sp. could form colonies on agar. According to the
SAR11 clade [33,34] consists of very small, heterotro-
phic marine proteobacteria that are found throughout the
oceans, where they account for about 25% of all micro-
bial cells. The detected marine bacteria (SAR11 clade)
were unable to form colonies on agar surfaces. These
bacteria exhibited a behavior that promotes growth and
dispersal rather than colony formation [33]. The term
“heterotrophic bacteria” includes all bacteria that use
organic nutrients for growth [16,19]. Because heterotro-
phic bacteria require carbon, nitrogen, and phosphorous
in a ratio of approximately 100:10:1 (C: N: P) [19]. Shi-
zuoka tap water contains heterotrophic bacteria as well as
the rich organic nutrient 1,4-dioxane.
3.4. Major ions and Physicochemical Parameters
for Shizuoka Water
The major ions compositions and contents were similar
for similar sampling stations in eastern Shizuoka. However,
Table 1. Identification of bacteria in shower water.
Types Name Accession No Match (%)
Before culture the shower water, only DGGE band (A) and band (B)
were detected
DGGE
band (A)
alpha proteobacterium
SKA54
(Citreimonas sp.)
AY317121
(GU213182)
126/128 (98%)
124/128 (96%)
DGGE
band (B)
alphaproteobacterium
IMCC10422
(Candidatus
Pelagibacter ubique)
FJ532495
(EU410957)
120/120 (100%)
120/120 (100%)
After culture on agar, the detected colonies (A and B were not possible
to culture on agar):
Colony-1 Pseudomonas
fluorescens GU177878 466/468 (99%)
Colony-2 Pseudomonas sp. FM161392 451/465 (96%)
major ion compositions varied according to the station
locations in relation to paper industrial sites. Instead, the
increased major ion concentrations (NO3
–, SO4 –2, Na+,
Ca+2, Mg+2) may be due to contamination from the paper
industry as the concentrations are higher in areas with
paper industries.
Figure 4 represents the water sampling station versus
electrical conductivity (EC) (Figure 4(a)), pH (Figure
4(b)) NO3 (Figure 4(c)) and K versus NO3 (K: NO3 = 1:1)
graph from 33 affected sites. The pH of the water samples
ranged from 6.81 to 8.09. Water samples investigated in
this study exhibit high concentrations of Cl–, 3
NO

3 NO

,
2
4
SO

, and 3 HCO

as the major anions and Ca2+ and
Mg2+ as the major cations. Tap, river, spring, and pond
water from Fuji and Fujinomiya Cities and the Uzui River
in this database have high mineralization, as shown by the
electrical conductivity measurements (Figure 4(a)), which
range from 200 to 340 S/cm. High EC values were also
observed at other stations, Gotenba, Mishima, and
Nomazu, which are located near Fuji City. The water sam-
ples from Fuji, Fujinomiya, and Mishima Cities have high
concentrations of 3
NO

(Figure 4(c)) in domestic and
surface water. Moreover, a high concentration of nitrate
was detected in tap water at Fujinomiya (near Fuji City);
this may be attributed to the local percolation of waste
water from industry in the nearby area.
3.5. VOCs (g/L) Concentrations
VOC contamination in the affected cities of eastern Shi-
zuoka are shown in Figure 5. The determined concentra-
tions of aquatic 1,4-dioxane (Figure 5(a)), and tert-butyl
ether (Figure 5(b)) VOCs versus pH (Figure 5(c)), are
mapped in this Figure 5. Cyclic ether (1,4-dioxane,
tert-butyl ether (MTBE, CH3OC(CH3))) and chloroform
were the dominant compounds detected by GC-MS in
various natural water (spring, pond, and river) and do-
mestic water sources (shower water) in eastern Shizuoka
Prefecture. The concentrations of 1,4-dioxan and tert-
butyl ether, including total volatile organic compounds
(VOCs), at 34 sites in March 2010 are shown in Figures
5(a), 5(b) and 5(c). According to GC-MS analysis, the
1,4-dioxane and tert-butyl ether concentrations were
higher than those from other VOCs, such as triha-
lomethane (THMs), toluene, chloroethylene, and xylene.
Fuji and Fujinomiya Cities are primarily polluted by cy-
clic ether. The Uzui river, which runs through Fuji and
Fujinomiya City, is one of the most polluted rivers. It is
contaminated by polar cyclic ether, 1,4-dioxane (66.6
g/L, tert-butyl ether (78.55 g/L)). The possible sources
of these cyclic ethers may be paper industries because
eastern Shizuoka has highly developed paper and chemi-
cal plants along its shores. According to a pollutant re-
lease and transfer resister (PRTR) report (April 2007-

Influence of Biogeochemical Qualities of Shizuoka Water on the Degradation of PVC Shower Hose209
(a) (b)
(c) (d)
Figure 4. Physicochemical mapping of Shizuoka water; (a) EC, (b) pH, (c) NO3
–, (d) K+ : NO3 – = 1:1 (meq/L).
(a) (b)
(c)
Figure 5. Distribution of (a) 1,4-dioxane, (b) tert-butyl ether; and (c) Total VOCs versus pH in 34 sampling station in Shizuoka.

Influence of Biogeochemical Qualities of Shizuoka Water on the Degradation of PVC Shower Hose
210
March 2008), the Oji paper mill (Fuji City, Japan) re-
leased polar cyclic ether and other organic chemical sub-
stances into waste waters following the Japanese stan-
dard value. According to a color mapping diagram (Fig-
ure 5(a)), samples from tap, river, pond, and spring wa-
ter from Fuji, Fujinomiya, and Suntou-gun (Koyama)
cities and the Uzui river, which runs through Fuji and
Fujinomiya Cities, are most contaminated by 1,4-dioxan
because the Uzui River (66.6 g/L) is the mouth of a port
connected with outflow from which the river discharges
into the Pacific Ocean. The 1,4-dioxane concentration
levels were unsatisfactory, with average levels ranging
from 1.8 to 66.6 g/L (Figure 5(a)), whereas Japan has
established a standard at 50 g/l. However, bacteria can
grow with 1,4-dioxane as a sole carbon source [35,36].
We compare the water qualities of unaffected Toyama
Prefecture with the water qualities from Shizuoka Pre-
fecture. Cyclic ether (1,4-dioxane) observed for the Shi-
zuoka region, whereas Toyama water (tap, ground,
spring) did not contain such kind organic pollutant.
3.6. Affected Cities and Paper Mill Site in
Shizuoka
PVC shower hoses are becoming hard, particularly in
paper mill locations in eastern Shizuoka, where the sur-
face and domestic water sources (tap, pond, river, spring
water) have been polluted by 1,4-dioxane and tert-butyl
ether (MTBE, CH3OC(CH3)). There are 85 pulp, paper,
and recycling mills in Fuji City, which is the largest
number of paper mills in one area in Japan, and other
cities in Shizuoka Prefecture also have pulp and paper
mills, as shown in Figure 1(a). PVC shower hoses were
reported to have become hardened in 11 cities in eastern
Shizuoka Prefecture. Most of the affected cities are lo-
cated in the pulp and paper mill area (Figure 1(a)). Nine
affected cities are in eastern Shizuoka, which is between
latitudes 35˚07'0.9''N and 35˚28'15.4''N and longitudes
138˚33'44.0''E and 138˚59'10.9''E (Figure 1(a)), and two
other cities are in central Shizuoka. Other unaffected
cities (No. 10 – No.18) from eastern Shizuoka are far
from paper industries area. In Figure 2(a), Fuji and Fu-
jinomiya Cities have the most paper mills, and the water
from tap, river, pond, and spring sources contains the
highest concentration of 1,4-dioxane and tert-butyl ether
(MTBE, CH3OCCH3; relative to those of Toyama, where
the water is not contaminated with polar cyclic ether and
shower hoses are not affected after being used for a long
time.
3.7. Damage Mechanism
Plasticizers reduce the polymer-polymer chain secondary
bonding and provide more mobility for macromolecules,
resulting in a softer, more easily deformable mass.
However, plasticizers (DINP), which contain oxygen and
carbon, may leach out from the shower hose. Therefore,
the hose becomes hardened, and the concentration of
carbon and oxygen decreases in the damaged hoses.
The quality of Shizuoka water is responsible for the
hardness of PVC tubes. However, there are 85 paper
mills in Fuji City alone, and other affected cities in east-
ern Shizuoka have paper and pulp mills as well. The po-
lar cyclic ether 1,4-dioxane is widely present in river,
pond, and spring water, including shower water, from the
possible sources of waste water from paper mills. Shizu-
oka shower water also contains the most abundant and
ubiquitous clade of marine heterotrophic bacteria as well
as organic nutrients (cyclic ether). Heterotrophic bacteria
can aerobically mineralize 1,4-dioxane as a sole carbon
and energy source in minimal salt medium. Therefore,
the bacterial growth increased inside the shower hose at
shower temperature with rich food 1,4-dioxane and
methyl tert-butyl ether, and need to use carbon-based
substrate plasticizers (DINP) for the extra energy sources
of increasing bacterial growth. Therefore, plasticizer
disappeared quickly from the shower hose, causing them
to lose flexibility and become hard and brittle.
However, at the incubation conditions, heterotrophic
bacterial formation is considerably slower at 20˚C than at
35˚C [16,37]. However, the most suitable set of incuba-
tion condition at 35˚C with pH of 7.0, the number of cells
capable of forming colonies significantly to those at 35˚C
and the incubation time at 35˚C was shorter [16]. Ac-
cording to our laboratory analysis, bacterial DNA con-
centration on PVC hose surface was higher exposed at
37˚C (B-surface) compare to at 25˚C (C-surface) (Figure
2(b)). The decreased concentration of oxygen and carbon
for the B-surface is also attributed to the prompt utiliza-
tion of plasticizer by increased bacteria and thus the
part-B become hard for the decreasing amount of plasti-
cizer (Figure 2(b)). Therefore, an understanding of the
relative position of the paper mills and the entire affected
areas in Shizuoka Prefecture provides useful indicative
information on the key processes leading to hardening of
shower hoses. Bacterial regrowth formation is a behavior
that allows prompt utilization of the substrate. The com-
bined exoenzymatic action of a growing fragment pro-
vides benefits to the individual cells when there is a rich
food supply [16].
4. Conclusions
The carbon and the oxygen concentration decreased in
the damaged shower PVC hoses. According to the raw
material composition (PVC: plasticizer = 100 : 70), plas-
ticizer contain oxygen in its primary structure. Therefore,
plasticizer leached out of the PVC hose, and the hose
become brittle because the plasticizer softens the PVC

Influence of Biogeochemical Qualities of Shizuoka Water on the Degradation of PVC Shower Hose211
hose. There are four types of heterotropic bacteria which
have been detected in Shizuoka tap water. The 1,
4-dioxane and total VOC concentration, which is known
to influence microorganism growth, was higher at a pH
range of 7-7.5 in the affected area. However, 1,4-dioxane
can influence the bacterial growth as a sole carbon source.
Therefore, heterotrophic bacterial growth increases at
shower temperature inside shower hose using organic
nutrients from water sources that allows prompt utiliza-
tion of the plasticizer DINP (substrate) in PVC shower
hose which is responsible for stiffness of shower hose.
Additionally this heterotrophic bacteria can effectively
utilize 1,4-dioxane for bacterial scissions of ether bonds
from Shizuoka tap water as a sole carbon and energy
source.
5. Acknowledgements
The research was financially supported by a grant-in-aid
for Scientific Research (No. 19310007) from the Minis-
try of Education, Science, Sports and Culture of Japan.
We are very grateful to Professor Shogo Naka mura,
University of Toyama, for bacterial analysis.
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