1. Results and implications of a longitudinal
biomonitoring study on mercury exposure
Michael Bader1, Sandra Brill1, Axel Schlieter1, Christoph Uebler2, Josef Guth2
1 BASF SE, Occupational Medicine & Health Protection, 67056 Ludwigshafen, Germany
2 BASF SE, Electrolysis I, 67056 Ludwigshafen, Germany
1
Occupational Medicine & Health Protection
Chief Medical Officer: Dr. med. Stefan Lang

2. 2
Inorganic Mercury
CNS impairment
kidney damage
inhalational
uptake
~ 80 %
gastrointestinal
resorption
< 0.01 %
dermal
absorption
~ 2 %
t1/2 ~ 40 days
cold vapour AAS
EU 20 µg/m3
Germany 20 µg/m3
US-ACGIH 25 µg/m3
US-NIOSH 50 µg/m3
© iStockphoto.com/Triton21

3. 3
Correlation between airborne and urinary mercury
Bender et al. 2006
Gefahrstoffe – Reinhaltung der Luft 66:465-468
Central conclusion:
The assessment of the health hazard of
exposed workers should rest upon the deter-
mination of mercury in urine, and not on the
concentration of mercury in workplace air.
Surveillance of 23 workers from 8 plants:
mercury in workplace air (PAS, 8-h-TWA, n = 44)
urinary mercury (postshift, n = 33)
mercury in air (µg/m3)
mercury in urine (µg/g crea.)
r = -0.030
p = 0.890

4. 4
HBM assessment values for urinary mercury
category remarks value unit
reference value w/o dental amalgam 1 µg/L
HBM-I value observation level 5 µg/g crea.
HBM-II value intervention level 20 µg/g crea.
category remarks value unit
DFG BAT 1982 200 µg/L
DFG BAT 1998 100 µg/L
DFG BAT 2005 30 µg/L
SCOEL BLV 2007 30 µg/g crea.
DFG BAT 2007 25 µg/g crea.
BGW 2012 25 µg/g crea.
ACGIH BEI 2013 20 µg/g crea.

5. electrolytic cell
graphite anodes
amalgam decomposer
pump
sodium amalgam
mercury
cathode
5
Chloralkali Electrolysis
http://commons.wikimedia.org/wiki/File:Chloralkali.svg

6. 6
Chloralkali Electrolysis Cell Room
Mercury used in chloralkali cells
European Union 5952 tons
Germany 1676 tons
BASF Ludwigshafen 734 tons
www.eurochlor.org (2012)
©BASFSE–OccupationalMedicine&HealthProtection

7. 7
Study group
no. of employees job category mercury exposure sampling frequency
184 production always low (semi)annually
22 maintenance
infrequently
& moderate
quarterly
9 cleaning
frequently
& significant
monthly
- 214 male employees from an alcoholates production plant
- regular biomonitoring since 1989
- comprehensive biomonitoring program since 2010
- experience and summary of the first three years

8. 8
(Semi)annual sampling: production
month of sampling & number of samples
µg mercury/g creatinine
BAT
BEI

9. 9
Quarterly sampling: maintenance
month of sampling & number of samples
µg mercury/g creatinine

10. Monthly sampling: cleaning
month of sampling & number of samples
µg mercury/g creatinine
frequent safety instructions
(gloves, trouser pockets, etc.)
daily change of working clothes
job rotation
10

11. Aggregated results
routine maintenance cleaning
employees (n) 184 22 9
samples (n) 531 83 231
median (µg/g crea.) 2 6 16
95 % (µg/g crea.) 8 23 30
%  BAT 0 4 13
cleaning 2010 2011 2012
samples (n) 77 81 73
median (µg/g crea.) 18 18 15
95 % (µg/g crea.) 38 31 22
%  BAT 18 19 3
11

12. month of sampling
µg mercury/g creatinine
job rotation
Individual follow-up: three examples
12
t1/2 ~ 40 days

13. 13
Individual follow-up: job change and job entry
month of sampling
µg mercury/g creatinine
job rotation beginners

14. 14
Summary and conclusions
- The terminal half-life (t1/2) of a compound should be considered.
- Biomonitoring, not air monitoring, is the current tool of choice for the analysis
and assessment of occupational mercury exposure inside BASF SE.
- Mercury exposure is under frequent control and generally below the German BGW/BAT.
- The intensity of exposure is a criterion for the selection of the monitoring frequency.
- Individual excursions trigger temporary job rotation and renewed safety instructions.