first part of your link and the premise for the study...
'Pulp and paper companies in Maine often burn wood, bark or paper-mill sludge to make electricity. '
and later...
'Although ash is often mixed with water (“conditioned”) before leaving the power plant, it can dry out after being stored in the field. Be careful when you handle any dusty soil amendment (like ash, lime or dry fertilizer). '
and....
https://en.wikipedia.org/wiki/Paper_...aper_recycling
from Limitations and impacts of paper recycling section...
'Along with fibres, paper might contain a variety of inorganic and organic constituents. Paper might contain up to 10,000 different chemicals'
was something else but i took too long... seems like the results might be different from a personal/residential perspective?...