The fate of urban-derived contaminants in boreal environments
Year: 2015
Type: dissertation
Abstract: Urbanization is progressing worldwide, with approximately 50% of the Earth s population currently living in urban areas, and this number is expected to increase to 60% by 2025. In Finland, as well as anywhere else, the population is gathered in the cities. At the moment, over 80% of Finns are living in urban areas. Urban areas are also known to produce a significant load of various pollutants to the surrounding environment. One of the significant forms of urban-derived pollutants emission to the surrounding environment is surface runoff. Pollution in urban surface runoff often comes from non-point sources, including motor vehicle emissions, coal and wood burning, tire wear, coal tar, creosote and asphalt leaching, oil spills, and runoff from building sites and other surfaces Our research was focused on distribution and toxicity of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and oil hydrocarbons. Previous studies in other countries indicated that above mentioned pollutants are often present in sediments adjacent to urban areas, may be toxic to aquatic life and recognized as priority pollutants for stormwater. In our study, notable amounts of hydrophobic organic compounds were found in the Lake Vesijärvi sediments and water column as well is in stormwater, urban air and runoff sediment from stormwater traps. Contaminant concentrations in the lake tended to decline with the distance from the urban shore. Toxicity of the sediments, determined with luminescent bacteria test was found to be lower in the Lake Vesijärvi than in the stormwater wells, however no clear gradient with the distance from the urban shore was found. In urban area degree of contamination and toxicity of the sediments depended on traffic intensity in the area. Toxicity of the both lake and stormwater well sediments was also found to correlate partly with organic contaminant content of the samples. These findings suggest that runoff from Lahti urban area has a notable impact on the Lake Vesijärvi condition. Comparison with Finnish contaminated soil guideline values displayed that present contaminant concentrations might be harmful for the natural ecosystem. It indicates that hydrophobic organic pollutants are important contributors to the Lake Vesijärvi sediment contamination and their inputs should be regularly monitored in order to avoid possible decline in the lake sediment quality.
Source: Työväentutkimus Vuosikirja
Author: Olga Honkonen
Language: English
Subfield: Health, Toxicology and Mutagenesis
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2206686435