Vurdering af eventuelle sundhedsmæssige konsekvenser ved eksponering til PFOS i det øverste skimmelag på havoverfladen under badning

Miljøstyrelsen (MST) har d. 4. juli 2022 bedt DTU Fødevareinstituttet om at vurdere eventuelle sundhedsmæssige konsekvenser ved eksponering til PFOS i det øverste skimmelag på havoverfladen under badning jf. koncentrationer, der fremgår af pkt. 2.1 i Niras’ rapport fra 13. juni 2022. Opgaven bedes løst under MSTs trækningsret. MST bemærker at der ikke findes gode data for dermal absorption af PFOS og at dette sammenholdt med mangel på solide eksponeringsdata, gør det udfordrende at udføre en kvantitativ risikovurdering. DTU Fødevareinstituttet må derfor meget gerne også beskrive, antagelser, forudsætninger og usikkerheder i vurderingen samt komme med forslag til eventuelt opfølgende arbejde, der vil kunne forbedre den sundhedsmæssige vurdering. Herunder f.eks. om det vil give mening at foreslå gennemførsel af studie for dermal absorption af PFOS og andre PFAS i regi af PARC

Assessing testicular germ cell DNA damage in the comet assay; introduction of a proof-of-concept

The in vivo comet assay is widely used to measure genotoxicity; however, the current OECD test guideline (TG 489) does not recommend using the assay to assess testicular germ cells, due to the presence of testicular somatic cells. An adapted approach to specifically assess testicular germ cells within the comet assay is certainly warranted, considering regulatory needs for germ-cell specific genotoxicity data in relation to the increasing global production of and exposure to potentially hazardous chemicals. Here we provide a proof-of-concept to selectively analyze round spermatids and primary spermatocytes, distinguishing them from other cells of the testicle. Utilizing the comet assay recordings of DNA content (total fluorescence intensity) and DNA damage (% tail intensity) of individual comets, we developed a framework to distinguish testicular cell populations based on differences in DNA content/ploidy and appearance. Haploid round spermatid comets are identified through 1) visual inspection of DNA content distributions, 2) setting DNA content thresholds, and 3) modelling DNA content distributions using a normal mixture distribution function. We also describe an approach to distinguish primary spermatocytes during comet scoring, based on their high DNA content and large physical size. Our concept allows both somatic and germ cells to be analyzed in the same animal, adding a versatile, sensitive, rapid, and resource efficient assay to the limited genotoxicity assessment toolbox for germ cells. An adaptation of TG 489 facilitates accumulation of valuable information regarding distribution of substances to germ cells and their potential for inducing germ cell gene mutations and structural chromosomal aberrations