Result 1 · Figure 3 · Nickel time series, 1995–2008

Raw-water nickel at BTB 2 rose from 10 µg/L in 1995 to 58 µg/L in 2005, exceeding the 20 µg/L TrinkwV limit by a factor of 2.9.

Routine monitoring at the two Stadtwerke Nettetal waterworks documented a sustained rise in raw-water nickel concentrations from the mid-1990s onward. Wasserwerk Breyell production well BTB 2 began at 10 µg/L in 1995 (the laboratory limit of quantification), crossed the 20 µg/L TrinkwV limit during the late 1990s, and reached 58 µg/L in 2005. Wasserwerk Kaldenkirchen production well KTB 4 oscillated around the limit and crossed it intermittently.

58 µg/L BTB 2 peak (2005)
20 µg/L TrinkwV limit (Ni)
10 → 58 µg/L BTB 2, 1995 → 2005

BTB 2 · Wasserwerk Breyell KTB 4 · Wasserwerk Kaldenkirchen 20 µg/L · TrinkwV drinking-water limit

Nickel concentrations in raw water from Tiefbrunnen 2 (Wasserwerk Breyell, BTB 2) and Tiefbrunnen 4 (Wasserwerk Kaldenkirchen, KTB 4), 1995–2008. Routine raw-water samples drawn before treatment; n = 15 (BTB 2), n = 10 (KTB 4). The dashed horizontal line marks the 20 µg/L nickel limit fixed by the German Drinking Water Ordinance (Trinkwasserverordnung 2001, in force at the time of the study; the limit remains 20 µg/L under the current TrinkwV). BTB 2 began below the limit at 10 µg/L in 1995, rose past it through the late 1990s, and reached its highest measured value of 58 µg/L in 2005. KTB 4 hovered close to the limit and crossed it intermittently. Source: Kandemiroglu (2011), Abb. 1.1. *