Convert nM to PPB

[JJJ]

Hi,

I would like to convert nM to PPB ( Parts per billion µg/L). Can you help me?

I would like to covert the following concetrations measured in water samples from the North Sea:

Ni = 3.66 nM

Cu = 1.61 nM

(Document: https://www.sciencedirect.com/science/article/pii/S0304420399000766?via%3Dihub )

[hypervalent_iodine]

You will need to show some attempt at answering this yourself. Where are you getting stuck?