Passive sampling for spatial and temporal monitoring of organic pollutants in surface water of a rural-urban river in Kenya

Passive sampling is an emerging monitoring strategy for surface waters and can be applied in a range of environments including remote locations. Silicone rubber (SR) as a robust single-phase passive sampler was applied to characterize the spatial and temporal variability of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs) and three phthalates, namely, dibutyl phthalate (DBP), benzyl butyl phthalate (BBP) and bis(2-ethylhexyl) phthalate (DEHP) in a tropical river traversing rural and urban catchments. OCPs and PCBs were not detected. Up to 31.8 ng/L of freely dissolved concentrations of PAHs were quantified andwere dominated by the lower molecular weight members. Mean concentrations of DBP, BBP and DEHP were 72.6 ng/L, 3.9 ng/L and 7.1 ng/L respectively. However, in sampling for phthalates using SR, quality control and assurance remains the key challenge and must always be ensured. Spatial variability in concentrations was evident and could be related to land use. Temporal variability was not significant. (C) 2017 Elsevier B.V. All rights reserved.