Ingestion of Tyre Crumb Rubber and Uptake of Associated Contaminants in Marine Invertebrates (Pandalus borealis) and Fish (Cyclopterus lumpus) – An Experimental Exposure Study

Crumb rubber (CR) produced from end of life vehicle tires is widely used on artificial sports fields and to create urban artificial surfaces. It is also used as a surrogate for tyre wear particles in experimental studies simulating the behaviour and effects of car tyre particles in the environment. It is known to contain a wide range of organic chemicals and metals, some of which are only just being identified and assessed. Weathering of such artificial surfaces releases both particles and the chemicals they contain into the environment, where they may be bioavailable and affect biota. N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) has been identified as a chemical marker for CR and tyre wear particles. Both 6PPD and its transformation product, 6PPD-quinone, have been shown to be toxic to a number of different freshwater and marine organisms. The current study examines the ingestion of CR (1 - 2.8; < 1.2 mm) by a marine invertebrate and fish, the gut retention time of ingested CR, and the tissue burden of tire-derived chemicals. Lumpfish (Cyclopterus lumpus) and Northern shrimp (Pandalus borealis) were exposed to CR in laboratory experiments for 21 days; 7 days of exposure to CR followed by 14 days of depuration. The stomach contents have been analyzed for ingested CR and selected tissues (Lumpfish liver and blood; Northern shrimp hepatopancreas and muscle) have been characterized for tire-associated chemicals and metals. Analytical chemical techniques involved ICP-MS, pyrolysis GC-MS, GC-MS/MS and HRGC-HRMS (ThermoFisher, Orbitrap). CR were found in 76% of exposed Lumpfish stomachs (n=90), where the number of CR particles in the stomach increased during the exposure and peaked around day 8 followed by a decrease throughout the depuration. Ingested CR was still found in some Lumpfish stomachs at the end of the experiment (day 21). Ingestion by Northern shrimp was analyzed by pyrolysis-GC/MS but. Analysis by HRGC/HRMS (ThermoFisher, Orbitrap) detected 6PPD up to 700 pg/g in blood from exposed Lumpfish, 6PPD was found both at the end of the exposure and at the end of depuration. ICP-MS analysis of metals did not show increased concentrations of metals in any of the tissues for exposed individuals or over time for either Lumpfish or Northern shrimp. The current results suggest that ingested CR can stay in the digestive system of Lumpfish longer than 14 days and that the particles may be leaching 6PPD during this period, suggesting bioavailability of both CR particles and associated chemicals to ecologically and commercially important marine organisms

Ingestion of car tire crumb rubber and uptake of associated chemicals by lumpfish (Cyclopterus lumpus)

Car tire rubber constitutes one of the largest fractions of microplastics emissions to the environment. The two main emission sources are tire wear particles (TWPs) formed through abrasion during driving and runoff of crumb rubber (CR) granulate produced from end-of-life tires that is used as infill on artificial sports fields. Both tire wear particles and crumb rubber contain a complex mixture of metal and organic chemical additives, and exposure to both the particulate forms and their leachates can cause adverse effects in aquatic species. An understanding of the exposure pathways and mechanisms of toxicity are, however, scarce. While the most abundant metals and organic chemicals in car tire rubber have multiple other applications, para-phenylenediamines (PDs) are primarily used as rubber antioxidants and were recently shown to cause negative effects in aquatic organisms. The present study investigated the responses of the marine lumpfish (Cyclopterus lumpus) to crumb rubber exposure in a controlled feeding experiment. Juvenile fish were offered crumb rubber particles with their feed for 1 week, followed by 2 weeks of depuration. Crumb rubber particle ingestion occurred in &gt;75% of exposed individuals, with a maximum of 84 particles observed in one specimen. Gastrointestinal tract retention times varied, with some organisms having no crumb rubber particles and others still containing up to 33 crumb rubber particles at the end of the experiment. Blood samples were analyzed for metals and organic chemicals, with ICP-MS analysis revealing there was no uptake of metals by the exposed fish. Interestingly, high resolution GC-MS analysis indicated that uptake of PDs into lumpfish blood was proportionate to the number of ingested CR particles. Three of the PDs found in blood were the same as those identified in the additive mixture Vulkanox3100. N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) was the most concentrated PD in both the crumb rubber and lumpfish blood. The transformation product 6PPD-quinone was detected in the rubber material, but not in the blood. This study demonstrates that PDs are specific and bioavailable chemicals in car tire rubber that have the potential to serve as biomarkers of recent exposure to tire chemicals, where simple blood samples could be used to assess recent tire chemical exposure in vertebrates, including humans

Beach litter sources around Nuuk, Greenland: An analysis by UArctic summer school graduate course students

Modeling studies illustrate the potential for long-range transport of plastics into the Arctic, although the degree to which this occurs remains relatively undocumented. We utilised a teaching exercise at a UArctic summer school graduate course in Nuuk, Greenland to conduct a preliminary in-depth analysis of beach litter sources in the Nuup Kangerlua fjord. Students and instructors collected and analysed 1800 litter items weighing 200 kg from one location in the fjord and another at its mouth. The results suggest a predominance of local sources to macrolitter, rather than long-range transport from Europe. Fisheries-related items and rope were common. Packaging which could be identified was largely suspected to be products distributed in Greenland, and soft plastics, which rarely disperse far from its source, were also common. The results suggest local measures to reduce mismanaged waste and emissions from fisheries are important for reducing marine litter in West Greenland.publishedVersio

Evolutionary Theories of Menopause

Menopause, the cessation of female reproduction well before death, is a puzzling phenomenon, because evolutionary theory suggests there should be no selection for survival when reproduction has ended. Nevertheless, menopause does exist in a limited number of species, and besides humans it has predominately evolved among toothed whales (Odontoceti). The aim of this thesis is to review both adaptive and non-adaptive theories. Of the latter, the most prominent proposes that menopause is a product of a physiological trade-offs between reproductive benefits early in life and negative late-life reproduction. Among the adaptive theories the grandmother hypothesis is the most acknowledged. This theory is based on inclusive fitness benefits gained from increasing the reproductive success of kin at an advanced age, when prospects of successfully raising additional offspring is reduced. Alternatively, the mother hypothesis suggests that increased investment in already produced offspring at late life explains menopause. There are support for both the care of mothers and grandmothers, but whether this is enough to compensate for repressed reproduction is debated. The reproductive conflict hypothesis provides a complementary explanation, and suggests that inter-generational conflict between either in-laws or kin selects the older female to shift investment into the younger female’s offspring due to asymmetries in how older and younger females are related to one another’s offspring. The evolution of menopause is a complex issue, containing many factors, kinship dynamics among the most important. Theories apply unequally to various species and populations, meaning an integrated approach is necessary for decrypting the evolution of menopause

Evolutionary Theories of Menopause

Menopause, the cessation of female reproduction well before death, is a puzzling phenomenon, because evolutionary theory suggests there should be no selection for survival when reproduction has ended. Nevertheless, menopause does exist in a limited number of species, and besides humans it has predominately evolved among toothed whales (Odontoceti). The aim of this thesis is to review both adaptive and non-adaptive theories. Of the latter, the most prominent proposes that menopause is a product of a physiological trade-offs between reproductive benefits early in life and negative late-life reproduction. Among the adaptive theories the grandmother hypothesis is the most acknowledged. This theory is based on inclusive fitness benefits gained from increasing the reproductive success of kin at an advanced age, when prospects of successfully raising additional offspring is reduced. Alternatively, the mother hypothesis suggests that increased investment in already produced offspring at late life explains menopause. There are support for both the care of mothers and grandmothers, but whether this is enough to compensate for repressed reproduction is debated. The reproductive conflict hypothesis provides a complementary explanation, and suggests that inter-generational conflict between either in-laws or kin selects the older female to shift investment into the younger female’s offspring due to asymmetries in how older and younger females are related to one another’s offspring. The evolution of menopause is a complex issue, containing many factors, kinship dynamics among the most important. Theories apply unequally to various species and populations, meaning an integrated approach is necessary for decrypting the evolution of menopause

DataSheet1_Ingestion of car tire crumb rubber and uptake of associated chemicals by lumpfish (Cyclopterus lumpus).docx

Car tire rubber constitutes one of the largest fractions of microplastics emissions to the environment. The two main emission sources are tire wear particles (TWPs) formed through abrasion during driving and runoff of crumb rubber (CR) granulate produced from end-of-life tires that is used as infill on artificial sports fields. Both tire wear particles and crumb rubber contain a complex mixture of metal and organic chemical additives, and exposure to both the particulate forms and their leachates can cause adverse effects in aquatic species. An understanding of the exposure pathways and mechanisms of toxicity are, however, scarce. While the most abundant metals and organic chemicals in car tire rubber have multiple other applications, para-phenylenediamines (PDs) are primarily used as rubber antioxidants and were recently shown to cause negative effects in aquatic organisms. The present study investigated the responses of the marine lumpfish (Cyclopterus lumpus) to crumb rubber exposure in a controlled feeding experiment. Juvenile fish were offered crumb rubber particles with their feed for 1 week, followed by 2 weeks of depuration. Crumb rubber particle ingestion occurred in >75% of exposed individuals, with a maximum of 84 particles observed in one specimen. Gastrointestinal tract retention times varied, with some organisms having no crumb rubber particles and others still containing up to 33 crumb rubber particles at the end of the experiment. Blood samples were analyzed for metals and organic chemicals, with ICP-MS analysis revealing there was no uptake of metals by the exposed fish. Interestingly, high resolution GC-MS analysis indicated that uptake of PDs into lumpfish blood was proportionate to the number of ingested CR particles. Three of the PDs found in blood were the same as those identified in the additive mixture Vulkanox3100. N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) was the most concentrated PD in both the crumb rubber and lumpfish blood. The transformation product 6PPD-quinone was detected in the rubber material, but not in the blood. This study demonstrates that PDs are specific and bioavailable chemicals in car tire rubber that have the potential to serve as biomarkers of recent exposure to tire chemicals, where simple blood samples could be used to assess recent tire chemical exposure in vertebrates, including humans.</p