Environmental Engineering Reference
In-Depth Information
Potential of Road Surface for a Non-point
Source of Pollutants - Result of Nationwide
Survey in Japan
Norihide Tamoto, Takeyoshi Matsui, and Takashi Sakakibara
Introduction
There are many water areas in Japan where the quality standards for closed waters
are not met. Eutrophication and its damages in closed waters, such as red tide and
water bloom, are still serious
[1]
.
In order to achieve the environmental water quality standards for closed waters,
various measures have been implemented in Japan. For example, the Comprehensive
Basin-wide Plans for Sewerage Works (CBPSW) are required to be drawn up when
determining the amount of works and the treatment levels for satisfying the
standards, which involves estimating the amount of pollutants that flow from
the land into the water
[2]
. However, there is little available data on the effects
of pollutants from non-point sources, and thus plans should be drawn up based on
rough assumptions.
Road surface is a major non-point source of pollutants particularly in cities.
Pollutants, such as nitrogen and phosphorus, which cause eutrophication, and heavy
metals and chemicals, which may adversely affect people's health and ecosystems
[3, 4]
have been widely detected in storm water runoff from road surface. However,
due to difficulties of predicting rainfall and high costs, only few surveys have been
conducted and thus there is little available data. Therefore, data is insufficient for
designing and taking countermeasures. In Japan, data that was collected several
decades ago is still used, and thus acquisition of latest data is an important topic.
In this study, pollutant loads from road surfaces were surveyed at 36 points in
four cities in Japan in 2006 and 2007. The objectives were to: (1) prepare new criteria
on pollutant load from road surface in Japan, and (2) analyze the runoff characteristics
N. Tamoto and T. Sakakibara
National Institute for Land and Infrastructure Management, Ministry of Land, Infrastructure,
Transport and Tourism, Government of Japan
T. Matsui
Japan Institute of Wastewater Engineering Technology
