Persistent organic pollutants in Swedish mosses
On behalf of the Swedish Environmental Protection Agency, IVL Swedish Environmental Research Institute led in 2015 a project aiming to examine the concentrations of persistent organic pollutants (POPs) in mosses.
Samples of red-stemmed feathermoss (Pleurozium schreberi) and glittering wood moss (Hylocomium splendens) were collected at 83 rural sampling sites. Of these, 20 samples were analysed for the following groups: polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), selected organochlorine pesticides, polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), dioxins and furans (PCDD/PCDFs), dioxin-like PCBs and perfluorinated alkylated substances (PFAS).
The sampling sites were selected to cover the whole of Sweden, in both the north-south gradient and in the east-west gradient. The sites were also chosen to represent both eventually elevated concentrations as well as low concentrations of POPs. Information on locations of industrial activities, population density and monitoring stations for organic substances in air and precipitation (Swedish national monitoring programme) were also used for the selection of sampling sites.
Generally, the concentrations of the analysed substances were very low, often close to or below the quantification limits for the analyses.
Significant correlation was found between the concentrations of PAHs, dioxin/furans and dioxin like PCBs in the mosses and the distance to the closest industry, and also to the distance from the southernmost point in Sweden. p,p-DDE concentrations in mosses showed a correlation to the distance from the southernmost point in Sweden, with the highest concentrations in the south. No correlation was found between the concentrations of p,p-DDE (one of the DDTs) in mosses and distance to the closest industry.
The concentrations of PAHs in mosses collected at sites located in the vicinity of three air monitoring stations (Råö, Aspvreten and Pallas) were in agreement with the concentrations of PAHs in air, with the highest concentrations in mosses and in air found in the south and the lowest in the north. Comparison between the PAH profile in air and in mosses showed a higher percentage of heavier PAHs in the mosses. This indicates a larger proportion of particular bounded PAHs in mosses.
HBCDD and PFAS were not detected in any of the analysed moss samples, which is consistent with a similar study conducted in Norway.