Table 1 The detailed information on sample origin.

From: Environmental implications and recovery potential of rare earth elements in solid residues from the incineration of sewage sludge

Sampling place

Sewage sludge ash (SSA) samples

Air pollution control system residues (APC) samples

Fluidized bed samples (FB)

“Gdańsk Wschód” Acronym: Gda

Sample 1: July 2014

Sample 2: November 2015

Sample 3: November 2016

Sample 4: September 2018

Sample 5: February 2019

Sample 6: March 2021

Sample 7: June 2021

Sample 1: November 2015

Sample 2: April 2016

Sample 3: November 2016

Sample 4: September 2018

Sample 5: February 2019

Sample 6: November 2019

Sample 7: June 2021

Sample 1: September 2018

Sample 2: June 2021

“GOŚ Łódź”

Acronym: Lod

Sample 1: June 2015

Sample 2: November 2015

Sample 3: April 2016

Sample 4: April 2016

Sample 5: July 2016

Sample 6: May 2018

Sample 7: February 2021

Sample 1: November 2015

Sample 2: February 2016

Sample 3: April 2016

Sample 4: July 2016

Sample 5: February 2021

Sample 1: June 2018

“GOŚ Dębogórze” Acronym: Gdy

Sample 1: June 2016

Sample 2: March 2021

Sample 3: June 2021

no samples collected

Sample 1: June 2021