Magnitude and drivers of legacy mercury emission from contaminated pulp-fiber sediments: Towards a refined risk assessment by accounting for emission to the atmosphere

Large amounts of toxic mercury (Hg), cellulose and wood fibers discharge during past paper and pulp industry formed hundreds Hg contaminated fiberbanks in Swedish inland and coastal watersheds.

Spread of legacy Hg from fiberbanks has recently been identified to cause high risk to bioaccumulate in biota, and a national guideline for risk assessment is urgently needed. However, the Hg emission from fiberbanks to the atmosphere remains unexplored.

This project aims to quantify the magnitude of Hg emission from fiberbanks and decipher the drivers controlling Hg redox transformation in sediment – that resulted Hg emission to the atmosphere.

We will combine multidisciplinary cutting-edge approaches including advanced Hg eddy covariance flux measurement technique, Passive air Hg Samplers, and stable Hg isotope analysis to: (a) deliver the first critical dataset on Hg emission from fiberbanks; (b) develop a cost-efficient long-term monitoring method for estimating fiberbank Hg emission; and (c) disentangle the geochemical and biological control on sediment Hg redox transformation to predict the fiberbanks Hg emission under future climate change scenarios.

The results from this project will substantially improve the risk assessment strategies by accounting for the emission of Hg to the atmosphere, and generate insights on long-term sustainable management of Hg contaminated fiberbanks.