Supplementary

Table S1 Summary of the sampling scheme. Macro-plastics were sampled in a total of 445 minutes in Sisimiut and 190 minutes in Nuuk. Meso- and large sized microplastics were sampled in 90 L in both Sisimiut and Nuuk and microplastics in 650 mL in 2 replicates in Sisimiut.

Sample	Town	Date of sampling	Duration of sampling (start and end time)	Weekday/weekend day	Field blank
Macro-plastics	Nuuk	06/09/2022	08:50-12:00	Weekday	N
	Sisimiut	30/08/2022	05:45-09:10	Weekday	N
		16/09/2022	16:15-18:15	Weekday	N
		23/11/2022	07:30-9:00	Weekday	N
		23/11/2022	20:30-21:00	Weekday	N
Meso-plastics	Nuuk	01/09/2022	16:00-18:25	Weekday	N
		04/09/2022	17:45-20:10	Weekend day	Y
		06/09/2022	06:20-08:45	Weekday	Y
	Sisimiut	25/08/2022	18:30-21:00	Weekday	Y
		26/08/2022	05:45-08:10	Weekday	Y
		27/08/2022	13:20-15:45	Weekend day	N
Microplastics	Sisimiut	22/11-2022	11 am	Weekday	Y
		23/11-2022	7am	Weekday	Y
		23/11-2022	8pm	Weekday	Y

Table S2 Indication of the mean number of microplastics in the analyzed blind samples (field- and lab-blinds, n=8) as well as detection limits (DL) calculated as the mean value + 3 x SD for the primary polymer types, and the total content of microplastics per sample and per liter of wastewater.

Polymer type*	PE	PP	PES	PS	PVC	PC	PMMA	PA	PUR	ABS	Total	Mass (µg)
Average number of MP per blind sample	2.0	3.5	0.3	0	0.2	0	0	0	0	0	6.0	0.12
DL (number of MP per sample)	10	12	2	1	2	1	1	1	1	1	17	0.26
DL (number of MP per liter)	15	18	3	2	3	2	2	2	2	2	26	0.39

* Polymer type: PE (polyethylene), PP (polypropylene), PS (polystyrene), PES (polyester), PVC (polyvinylchloride), PC (polycarbonate), PMMA (polymethylmethacrylate), PA (polyamide), PUR (polyurethan), ABS (akrylonitril-butadien-styrene)

Table S3 Summary of a wet wipe survey in shops in Sisimiut. An item of all types of wet wipes in the shops in Sisimiut was acquired and undergone FTIR-analyses to determine the primary polymer and eventual secondary polymer of the tissue.

Brand	Trade name	Application purpose (baby, sanitary, cleaning)	Declaration (%PET, %viscose, bamboo etc)	FTIR-analysis
Brand	Trade name	Application purpose (baby, sanitary, cleaning)	Declaration (%PET, %viscose, bamboo etc)	Primary polymer	Secondary polymer
Sanitary purposes
Änglamark	Bamboo wipes	Baby	Bamboo	Viscose
Änglamark	Dermacare makeup wipe	Sanitary, facial	Bamboo	Viscose
Änglamark	Make up cleansing wipe	Sanitary face	?	PES (PET)
Änglamark	Wipes	Baby	60% PES, 40% viscose	PES (PET)
Cherish	Facial cleansing wipes 4 in 1	Sanitary, facial	?	PES (PET)
Domestos	Absolute Hygiene	Cleaning universal	Natural fibers	Viscose
Everyday eye depend	Make up removal wipe	Sanitary, face	100% viscose	Viscose	?
Grøn balance	Make-up 3i1 renseservietter	Sanitary, facial	70% viscose /30% polyester	PES (PET)
Grøn balance	Vådservietter	Baby	40% viscose /60% polyester	PES (PET)
Huggies	Natural	Baby	Natural fibers	Cellulose
Hygienic Wipe	Hygienic Wipe	Sanitary, hands, facial and surfaces	?	Viscose	?
Kleenex	Water fresh wipes	Sanitary, hand & facial	?	PP	Cellulose
Libero	Hand & face wipes	Sanitary, hand & facial	?	Cellulose
Libero	Wet wipes	Baby	100% viscose	Viscose
Libresse	Dailies V-gentle	Sanitary, intimate areas	?	PES (PET)
Lotus	Sensitive	Sanitary (toilet paper)	Natural fibers	Cellulose
Nivea	Cleansing wipes	Sanitary, facial & eyes	Natural fibers	?
Vivag	Intimservietter	Sanitary, intimate areas	?	Viscose
Vivag	Intimservietter specielt til intimzonen	Sanitary, intimate areas	?	Viscose
Cleaning purposes
Ajax	Multi action	Cleaning glass wipes	Natural fibers	Viscose
Ajax	Universal	Cleaning universal	Natural fibers	Viscose
Ajax	Universal antibacterial	Cleaning universal		Viscose
Coop	Cleaning wipe lemon	Cleaning universal	Viscose / Polyester	PES (PET)
Coop	Cleansing wipes- bathroom	Cleaning bathroom	Viscose / Polyester	PES (PET)
Coop	Stad-servetter	Cleaning bathroom	Viscose / Polyester	PES (PET)
Klorin	Klorin wipes	Cleaning universal	?	PES (PET)
Lysol	Multipurpose wipes	Cleaning universal	?	Viscose