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Heavy metal contamination in the urban river has become the most severe problem in the urban environment, especially the zinc (Zn) compound is harmful to the environment at current levels of exposure. This study aims to assess the impact of urbanization and industrialization on Zn pollution in surface sediment at the Umeda River. Triplicate surface sediment samples were collected at nine sample points. An atomic absorption spectrophotometer was used for analyzing the Zn and Fe concentrations. The surface sediments in the Umeda River contained 48–159 mg/kg of Zn. The results indicated that Zn concentrations were abundant in the ascending order of 600–1,000 μm, 300–600 μm, and smaller than 300 μm. The higher the grain size, the higher the particulate organic carbon which might contribute to the higher Zn and Fe concentrations. In addition, the sediment quality guidelines indicated that the Zn levels in the study area did not constitute a major threat to biota. Normalization with Fe showed that the Zn pollution in surface sediment had been influenced by anthropogenic activities such as industrialization and urbanization. HIGHLIGHTS Unusual condition of Zn contents in the surface sediment compared with other studies.; Represents the zinc studies in urban areas with some type of land use in the watershed.; The first heavy metals research in the Umeda River, Aichi, Japan.;

Eutrophication in an estuary occurs as an effect of the enrichment of nutrient inputs from rivers. This condition has become one of the most common environmental issues experienced around the globe and especially in Japan. Atsumi Bay is a eutrophic coastal area in Japan. The objective of this research was to analyze the influences of nutrient inputs from the Umeda River into Atsumi Bay on pre- and post-rainfall water quality conditions. This study was conducted from July to October 2010. The results showed a decrease of surface salinity after rainfall indicating that huge freshwater inputs had overlaid the surface layer of Atsumi Bay rather than the bottom layer. Moreover, post-rainfall conditions showed an increase of chlorophyll a as an effect of phytoplankton growth, followed by an increase of particulate nutrients. On the other hand, dissolved nutrients decreased due to uptake by phytoplankton and dilution by freshwater. [ABSTRACT FROM AUTHOR]