Urban stormwater sediment risk assessment from drainage structures in Bogotá, Colombia

Urban stormwater sediments are associated with non-point source pollution. In Bogotá, Colombia, two urban rivers (Molinos - Arzobispo) and a constructed wetland with contributions from stormwater runoff located in areas of different land uses (residential, commercial, and parking lot) were selected. Sediments collected from the structures were characterized to determine heavy metal (HM) concentrations and the associated risks to the environment and human health through indices to propose criteria for sediment management. The HM concentrations found by ICP decrease as follows: Cu > Zn > Pb > Ni > Cr > Cd. Due to the Ni content, there is a tolerable to elevated risk in adults and high risk in children of developing cancer through involuntary ingestion. Dermal contact risk from Cr is tolerable in sites where the land use is not residential. No threats to human health were found from non-carcinogenic metals. Cu and Zn for all the indices analyzed present a high and medium-high risk of environmental contamination, respectively. The enrichment factor shows that the origin of the metals is mainly from anthropogenic sources. No ecological risks are expected with the sediments from residential land use, while sediments from other land uses generate intermediate risks. The risk levels found are a source of information to establish threshold values in which sediments present a risk to the environment and human health.