Contaminant Buildup and Distribution on Urban Impervious Surfaces at Parking Lots

Aleksandar Đukić1, Boris Krunić1, Branislava Lekić2, Vladana Rajaković Ognjanović2, Zorana Naunović2

 

 

1 Jaroslav Černi Institute for the Development of Water Resources, Jaroslava Černog 80, 11226 Pinosava-Belgrade, Serbia; E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

2 University of Belgrade - Faculty of Civil Engineering, Department of Hydraulic and Environmental Engineering, Bulevar kralja Aleksandra 73, 11000 Belgrade, Serbia

 

Abstract

This paper presents the results of experimental investigations on contaminant buildup, distribution and dynamics on asphalt surfaces of parking lot in Belgrade, Serbia. The investigated pollutants were solids, nutrients, oils and grease, chlorides, sulphates and heavy metals. Contaminant buildup was found to be highly influenced by traffic intensity and local climate conditions. The highest surface loads were found for solids, chemical oxygen demand, iron and zinc. Pearson's correlation revealed a strong correlation between total suspended solids, heavy metals and phosphorus, but settleable solids, oils and grease, total nitrogen, biochemical oxygen demand and chlorides are weakly correlated to other contaminants. Bonding of contaminants to the solid phase of the urban runoff was examined and results show that much higher concentrations were associated with finer fractions. The parking lot contaminant spatial distribution results for the examined sites were largely scattered and did not follow any particular pattern.

Keywords: contaminant buildup, impervious surface, metals, parking lot, total suspended solids.

 

 

Introduction

 

Contaminants accumulate on urban surfaces during dry weather periods (contaminant buildup) and are washed off by surface runoff during rain events. The following main groups of organic and inorganic constituents of urban runoff are typically dealt with because of their frequent occurrence and relation to major harmful effects to both humans and the environment: solids, biodegradable organic matter, nutrients, heavy metals and pathogens (Davis and McCuen, 2005). In the context of urban drainage, this list is widely referred to (Burton and Pitt, 2002; Butler and Davies, 2004). Solids present in runoff can be of different origin and exhibit various impacts, mainly consisting of small particles of eroded surface debris (Kayhanian et al., 2012). A number of other contaminants are associated with suspended solids (Herngren et al., 2006), heavy metals in particular (Deletić and Orr 2005). Heavy metals typically present in urban runoff are: iron, copper, lead, zinc, cadmium, nickel and chromium. Their excessive discharges into aquatic environments through urban runoff may result in toxic responses in animals, degradation of water quality for recreational use and restrictions on fish consumption (Beck and Birch, 2012). Iron in runoff is usually not considered a pollutant; however, due to its high concentrations it may play a significant role in the removal mechanisms of other pollutants (Hvitved-Jacobsen et al., 2010). Biodegradable organic matter and nutrients cause the depletion of dissolved oxygen in urban drainage systems and natural aquatic environments that can affect the performance of these systems and influence the growth and survival of particular organisms (Eriksson et al., 2007; Berretta and Sansalone, 2011). Organic micropollutants include a variety of different organic substances, such as: pesticides, petroleum hydrocarbons, phenols, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), etc. that are typically discharged into the environment in trace amounts. 

As reported by Eriksson et al. (2005), at least 656 organic micropollutants can be present in stormwater runoff. Additionally, pathogenic microorganisms are frequently present in stormwater runoff, although to a lesser extent than in sewage, and can deteriorate the quality status of the receiving waters and prevent their use for recreation and irrigation purposes (McCarthy et al., 2012) and may even create a serious public health concern (Sidhu et al., 2012). The contaminants that are temporarily accumulated at the impervious and semi-impervious urban surfaces have their origin in inputs via the atmosphere (Zereini and Wiseman, 2010), inputs from road materials (Whelton et al., 2013) and inputs from human activities, including vehicular traffic. It has been observed that the method and effectiveness of street cleaning may also affect pollution related to road runoff (Deletić et al., 1998). Parking lots, along with roads, are often the principal source of water pollution in urban areas. A common assumption is that higher contaminant amounts are associated with sediment buildup on roads and parking lots during longer dry periods between any cleansing (i.e. rainfall) events (Wicke et al., 2012). The fate and transport of contaminants within a roadside environment are very complex, and studies have revealed that persistent contaminants that tend to bio accumulate in tissue, such as metals, produce long lasting impacts on terrestrial and aquatic organisms (Lancaster and Beutel, 2011). Most of the street and parking lot surface dust and particulate matter (by weight) is derived from local soil erosion products, some materials are contributed by motor vehicle emissions and mechanical wear of vehicle components, and minor contributions are made by the erosion of street surfaces in good condition (Fujiwara et al., 2011). The extensive list of specific road runoff contaminants and their primary sources can be found in literature (US EPA, 2005).