Sampling Bergen

All glass funnels used during sampling were washed with microplastic free water, covered in aluminum foil to prevent contamination, and air dried before use. Sampling in Bergen started Monday July 1st at 13:27 and ended Wednesday July 10th at 09:35, excluding the weekend. The bottles were covered with aluminum foil and moved inside during the weekend to prevent people in the neighborhood tampering with the project. During the sampling time, each funnel was washed with microplastic free water (100 mL) every day between 09:00 and 09:30. After sampling, the solvent bottles were covered with aluminum foil before capped and stored in a fridge.
During the sampling time, 30 mL of rain was recorded using a measuring cylinder. The cylinder was placed next to the solvent bottles, and it was not emptied. For the first four days 5 mL of rain was recorded, and on the fifth day 9 mL, continuing into the second week 30 mL of rain was recorded on the seventh day.

Sampling surroundings

The sampling rig was placed on a bench outside of Eurofins Bergen. The immediate surroundings of the sample taking is a parking lot. Less than 2 meters from the rig, there was a parking spot, meaning cars would frequently drive close to the sampling process.
In the general vicinity there is a highway, mountains, trees, bushes, boat marina, and other industries.

MICROPLASTIC FREE WATER

Eurofins location in Bergen filtered Milli-Q water using AnodiscTM 47 (0.2 µm, 47 mm, WhatmanTM) filters. The bottles were washed with filtered microplastic free water (approximately 10 mL) two times before refilled with microplastic free water (approx. 1.0 L). The microplastic free water was contained in glass bottles with plastic lids (1 L) and the top was covered in aluminum foil to avoid contamination from the lids. A total of 20 bottles, 5 for each laboratory, was filled and shipped to three different Eurofins laboratories in Scandinavia, 1) Denmark, 2) Alta, Norway, 3) Finland (Rovaniemi and Pelkosenniemi).

Bottles for sampling

Solvent bottles (2.5 L, n = 36) were prepared at Eurofins Bergen using microplastic free water filtered at the location as mentioned (see Microplastic free water). The solvent bottles were washed two times with filtered microplastic free water (approximately 100 mL) two times before refilled with microplastic free water (500 mL). For Eurofins Bergen 8 solvent bottles were prepared and for Denmark, Alta, Rovaniemi and Pelkosenniemi 7 solvent bottles were prepared and shipped for each laboratory. In addition, each laboratory recieved 7 glass funnels (15 cm in diameter).