ZINC in Waters


Zinc in Waters

Groundwater is crucial for the extraction of our drinking water and the supply of streams, rivers, and lakes. Equally important is the quality of the groundwater. Harmful contamination or significant pollution due to the direct discharge of wastewater or the infiltration of rainwater must be avoided. The requirements of the European Water Framework Directive aim to ensure water quality across Europe. If poor water quality is detected, measures must be taken to improve it. There will be two Europe-wide lists of substances considered hazardous to water: the so-called 'Priority Substances'. The content of these 'priority hazardous substances' in waters should be limited and their discharge into water bodies reduced to zero. Zinc is not mentioned in these lists and is not classified as a 'substance of very high concern' (SVHC) according to REACH.

For the verification of compliance with the required groundwater quality, environmental quality standards and de minimis thresholds (GFS) according to the EU Water Framework Directive (WFD), the German Water Resources Act, and the German Working Group on water issues of the federal states (LAWA) are used. For roofing and facade construction materials, this proactive water management, considering soil and water protection, requires a specific consideration to avoid pollutant entries. For assessing the rainwater quality from zinc surfaces, corresponding environmental quality standards and GFS values are available. These quality requirements prevent harmful contamination of groundwater. Through a project-specific assessment, it can be demonstrated that significant pollution does not occur in the specific application case and that the regional quality requirements are met.

LAWA-GFS report 2015 '... If the substance entry occurs through the unsaturated soil zone/ seepage path, the place of assessment or prognosis, whether the GFS values are undercut, is in the seepage water at the entry into the groundwater.

... 'If the prognosis shows that the GFS values are exceeded at the entry into the groundwater or not only low substance loads will be present, there is definitely a usage situation according to § 9 para. 2 no. 2 WHG. The permissibility must be examined in more detail in individual cases.'

'The GFS values are used in the examination of whether the predicted or determined substance concentrations due to an intended action or concrete application for groundwater use cause an adverse change in the (ground) water quality. […] If the GFS values are met in the medium to be introduced, possibly with overall low loads, then according to § 48 para. 1 WHG, it is assumed that an adverse change in water quality is not to be expected and thus a reason for refusal according to § 12 para. 1 WHG - with regard to a possible substance entry to be evaluated according to the GFS values - is not given.'

For components and surfaces made of zinc, a calculation program by the environmental institute ARCHE, B-Gent, is available for this prognosis. The assessment methodology was verified by the internationally recognized engineering firm Rambøll, DK-Copenhagen.

Easily check whether the environmental quality objectives for zinc are met at your project. Perform the RainwaterCheck-ZINC here for free and quickly:

Derivation of environmental quality objectives for zinc:

  • Natural background concentrations, fluctuations from 9.9 – 196 µg/l [1]
  • Derivation 'base value' (90th percentile) for zinc 49.8 µg/l *
  • PNEC zinc (predicted no effect concentration) according to REACH RAR 7.8 µg/l
  • Derived de minimis threshold (GFS) according to LAWA 60 µg/l (total concentration)
  • Environmental quality standard (EQS) for zinc immissions 10.9 µg/l [2]
  • Environmental quality standard (EQS) for zinc in rivers/lakes (suspended matter/sediment) 800 µg/l [3]
  • * Case: Increased natural, geogenic background concentrations
  • LAWA-GFS report 2015: In the case that there are higher natural background values, the authorities are given discretionary power: 'If the regional geogenic background values in the groundwater exceed the de minimis thresholds, the responsible authorities can set values for the individual case, considering the derivation criteria set out here (see Annex 1).'
  • Based on this approach of LAWA, the RainwaterCheck-ZINC (www.zn-rate.com) only uses the environmental quality standard according to REACH for the assessment of zinc entries into, e.g., groundwater. This simplifies the assessment of the risk of harmful contamination, without the need to know the background situation.

[1] due to geogenic zinc concentrations, Kunkel et al 2004

[2] WFD - Water Framework Directive Annex VIII substances: zinc by Water Framework Directive - United Kingdom Technical Advisory Group (WFD-UKTAG)

[3] OGewV - Surface Water Ordinance 2016, Germany


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