Regional Analysis on Decadal Variation in Aspects of Water Quality in Three Contrasting Coastal Systems of Ishikawa Coast, Japan

This study examines drivers and trends of change in time and space in some coastal water quality parameters and management/cultural practices on the Ishikawa coast, Japan, between 1984 and 2009. Generally, chemical oxygen demand (COD) and dissolved oxygen (DO) concentrations varied significantly () across the three coastal compartments (Kanazawa area (KNA), Noto area (NTA), and Nanao area (NNA)), and pH and DO concentrations varied significantly () over the last three decades, suggesting that human perturbation within the last three decades varied along the coast and may be more relative than environmental change impact. Other water quality variables showed different spatial and temporal patterns and implications across the coastal compartments. Although there is a uniform approach to the development of water quality standards in Japan, these results suggest that setting stricter standards may be required by the prefectural government in collaboration with industry, stakeholders groups, and coastal community resource users.