Contamination of the Shinano River Water
with Mutagenic Substances after the Niigata Chuetsu Earthquake
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| Takanori Fujimoto1), Yasuo Tsuchiya1),
Norio Shibuya2), Mayumi Taiyoji3),
Toshikazu Nishiwaki3), Kazutoshi Nakamura1)
and Masaharu Yamamoto1) |
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1) Department of Community Preventive Medicine, Niigata
University Graduate School of Medical and Dental Sciences
2) Niigata College of Medical Technology
3) Niigata Agricultural Research Institute Food Research Center |
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(Received November 10, 2006)
(Revision accepted for publication December 28, 2006)
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While normally monitoring the Shinano River water quality,
including examinations for mutagenicity, the Niigata Chuetsu
Earthquake suddenly occurred on October 23, 2004. However, the
influence of this earthquake on the mutagenicity of river water
has not yet been well studied. To clarify the regional and
seasonal changes in mutagenicity of the Shinano River water,
blue rayon was suspended for 24 hrs at 4 sampling sites, once a
month from September 2004 through August 2005. Mutagenicity was
evaluated by the Ames test using Salmonella typhimurium
TA98 (TA98) and TA100 with or without metabolic activation by S9
mixture. To detect and identify poly-aromatic hydrocarbons that
may be responsible for the mutagenicity of the river water, we
analyzed benzo[a]pyrene, benzophenone, 4-nitrotoluene, or other
compounds using gas chromatography-mass spectrometry and total
ion chromatogram spectra. Positive manifestations of TA98 with
S9 mixture were observed at the 4 sampling sites throughout the
12-month test, showing a tendency to be higher at the downstream
site and in winter. However, the highest mutagenicity was
observed in the sample collected at the most upstream sampling
site in December 2004, and fluoranthene or pyrene consisting
mainly in coal tar was detected only in the samples collected in
December 2004. Although benzo[a]pyrene, benzophenone, and
4-nitrotoluene were below the detection limits, non-mutagens
such as aliphatic hydrocarbons or esters were frequently
detected. Our findings indicate that either fluoranthene or
pyrene was mainly responsible for the mutagenicity of the river
water in December 2004, suggesting the possibility of oil
contamination caused by the Niigata Chuetsu Earthquake. |
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the Shinano River water; mutagenicity; the Ames test; gas
chromatography-mass spectrometry; total ion chromatogram spectra |
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