TITLE:
Assessment of the Water Quality in the Ariake Sea Using Principal Component Analysis
AUTHORS:
Toshinori Tabata, Kazuaki Hiramatsu, Masayoshi Harada
KEYWORDS:
Ariake Sea, Principal Component Analysis, Nutrients, Anticlockwise Tidal Residual Flow
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.7 No.1,
January
14,
2015
ABSTRACT: The aim of this study is to investigate the
condition of the Ariake Sea, Japan, which has been suffering from severe
environmental issues for the past few decades. Water quality data have been
generated from several points in this area for over 30 years by the Fukuoka,
Saga, Kumamoto, and Nagasaki prefectures. In order to understand the
characteristics of this sea, principal component analysis (PCA) was utilized
using 11 water quality parameters; transparency, temperature, salinity,
dissolved oxygen (DO), chemical oxygen demand (COD), dissolved inorganic
nitrogen (DIN), ammonium-nitrogen (NH4+-N), nitrate-nitrogen (NO3--N), nitrite-nitrogen (NO2--N), phosphate-phosphorus, (PO43--P) and silica. PCA conveyed the amount of nutrients originating from the
river, the organic pollution level, and seasonal changes. Subsequently,
principal component scores were calculated for each point. It was concluded
that the Ariake Sea environment has been affected by two main factors, which
are the nutrients from the Chikugo River and anticlockwise tidal residual flow.
These two factors must be considered for the environmental restoration of the
Ariake Sea.