One of the main goals of GerES is to document a trend in time of population exposure. Data from the different surveys have to be made comparable to achieve this goal:
A comparison is only possible for the same age group (25 to 69 years of age). Data from 1990-1992 was recalculated for this age group ignoring data for the 18 to 25 years old and the 69 to 79 years old population.
Data from 1997-1999 was only recalculated for subjects with German nationality.
- Data from 1990-1992 were weighted using population data from the 1998 German Microcensus.
The following substances were analysed in both surveys: arsenic in urine, lead in blood, cadmium in blood, cadmium in urine, mercury in blood, mercury in urine and PCP in urine, in addition 1-Hydroxypyren in urine.
In both surveys PCP, lindane und permethrin were analysed in house dust.
Trend data for the concentrations of metals in tap water of the 25 to 69 year old population is shown in the results chapter (drinking water).
The mean concentration of arsenic in urine, lead in blood, mercury in urine and PCP in urine has decreased. This is caused by the decreasing level of pollution by the mentioned substances above all in the food chain. Since the mean concentrations of cadmium in blood and urine are close to the detection limit, the 95th percentiles should be used to evaluate a trend in time. The 95th percentiles have decreased in both cases. A decrease could be observed for mercury in East-Germany (0,71 µg/l vs. 0,62 µg/l) and an increase in West-Germany (0,46 µg/l vs. 0,6 µg/l).
In GerES III PAH were included in the survey programme. At the same time samples from GerES II were analysed retrospectively. In East-Germany the concentration of 1-hydroxypyrene obviously decreased and approached the level in West-Germany. The reduction might be caused by the decrease of PAH emissions (industrial emissions, domestic heating with coal) in East-Germany.
The mean concentrations of PCP and lindane decreased between 1990-1992 and 1997-1999. The use of PCP is forbidden since 1989. The use of lindane in plant protection agents was forbidden in the EU in 2001. However less products containing lindane appeared on the market in recent years.
Pyrethroids were often used as substitutes for PCP. This could be shown by the results of GerES. In West-Germany the mean concentration of permethrin in house dust increased from 0,06 mg/kg in 1985/86 to 0,23 mg/kg in 1990/92. From 1990/92 to 1997/99 the mean concentration did not change significantly.