New stormwater priority pollutants: comparison with international classifications, quality criteria and monitoring programs

Abstract

Stonnwater discharges are generated by rain runoff from land and impervious areas such as
roads, parking lots, and roofs during rainfall and snowmelt events. It contains an array of
different pollutants such as organic matter, particles, heavy metals, inorganic trace elements
and xenobiotic organic compounds (XOCs). It is important to consider the hazards concerning
these pollutants when considering design of monitoring strategies, comparing different
handling strategies for stonnwater utilisation, treatment methods and discharge to receiving
waters.
In the EU 5FP funded Daywater project a list of selected stonnwater priority pollutants
(SSPP) was identified, which has been used for assessing pollutant sources and fluxes,
behaviour and fate during passage through best management practices (BMPs) and the
environmental risk associated with their subsequent dispersal. The methodology used;
Chemical Hazard Identification and Assessment Tool (CHIAT) aims at selecting relevant
SSPP e.g. and can be used for development and evaluation of monitoring programmes.
The Daywater SSPP-list consists of water quality parameters (BOD, COD, SS, nitrogen, pH
and phosphorus); metals (Cd, Cr, Cu, Ni, Pb, Pt and Zn); PAHs (naphthalene, pyrene and
benzo[a]pyrene); herbicides (pendimethalin, phenmedipham, glyphosate and terbutylazine);
and other XOCs (nonylphenol ethoxylates, pentachlorophenol, di(2-ethylhexyl)phthalate,
PCB-28 and MTBE) representing persistent, ubiquitous compounds and compounds deriving
from specific anthropogenic sources.
The list was compared with data found within the Danish nation-wide monitoring
programmes for the aquatic environment (NOV A2003 and NOV ANA); European monitoring
programmes; pollutant registers; individual European legislation; as well as quality criteria
and limit values. The comparison reveals differences since most of these are set on arbitrary
criteria or focuses on the current EU legislation. Overlaps was found with the studied
programmes, but also some "new" compounds was selected; platinum, herbicides and MTBE
which indicate that revision of existing monitoring programmes is needed and that stonnwater
contains more hazardous pollutants than previously anticipated.