Novel organic pollutants from recycling of organic waste as risk factors for human exposure

The field campaign was completed in 2021. In addition, several experimental lab-based studies were completed. This included composting of human feces, mushroom growth tests on biogas digestates, and soil aggregate stability testing. In addition to the earlier screening of Norwegian digestates for pharmaceutical residues (Ali et al, 2019), digestates from 12 biogas production plants were analysed for selected perfluoroalkyl substances (PFASs) and legacy persistent organic pollutants (POPs). Toxicity testing of biogas digestates was concluded in 2021, a comprehensive battery of Zebra-fish based toxicological endpoints were measured and compared. This included early larvae development and gene expression. in-vitro toxicity testing was conducted on selected Benzotriazoles found to be major constituents of digestates. All toxicological and level information on Benzotriazoles were used for updated risk modeling using QSAR/ADME modeling. finally a quantitative method for the determination of Benzotrazoles in human monitoring (urine) was used and applied for a recent cohort study. The details of the NovelPol research are summarised in a comprehensive final report (attached).

The NovelPol team looked into the levels and fate of organic pollutants in biogas digestates. The list of chemicals identified includes selected pharmaceuticals and personal care products (PPCPs), poly- and perfluoroalkyl substances (PFASs) and persistent organic pollutants (POPs). For some chemicals, uptake in cereals and mushrooms are reported. Toxicological follow-up studies revealed hazardous effects in Zebrafish experiments and bioassays. Indication of compounds and substraterelated effects were established. Based upon our results, we are, therefore,recommending to 1. establish further investigations of relevant pollutant fate in digestate used for soil amendment 2. implement toxicological testing of biogas digestates. 3. extend the research with comprehensive target suspect screening for the identification of hitherto unknown pollutants. 4. establish sustainable regulation frames allowing the safe application of digestates in agricultural applications.

The NovelPol project application details the scientific evaluation and characterisation of sources, dispersion and exposure processes for novel organic pollutants including contaminants of emerging concern (CEM) of different organic wastes originating from, e.g., households, food industry, agriculture, fishery and sewage treatment. This information is of vital importance in order to prevent unwanted dispersion of contaminants. An important part of this project will therefore also be the close interaction with relevant industry to implement routines to prevent dispersion. Common for the original biological material that results in organic residues is the exposure to a large number of chemicals, including pharmaceuticals for human and veterinary use, personal care products, hygiene products, product stabilisers, industrial chemicals (incl. flame retardants, plasticisers, dyes), and many more. Many of these substances are directly in contact or even introduced into the target organisms and the majority is again excreted with the feces/ urine. The majority of such organic waste products is used in agriculture, usually after no (manure) or some treatment (sewage sludge, biogas digestates, composts), as soil amendment and fertiliser. However, the risk of potential human exposure due to up-concentration of environmental stable contaminants (not degraded during various treatment processes) in agricultural products is largely unknown and needs thorough scientific assessment. Therefore, the here proposed NovelPol initiative will evaluate different product lines for organic residues applied to agricultural land in Norway and perform a first life cycle assessment (LCA) for these products with focus on origin, transformation and fate of anthropogenic organic pollutants for these products. The here represented research team will communicate closely with relevant producers in order to provide information for product improvement and development more sustainable production lines.