Soil contamination map

According to § 5 Paragraph 1 of the State Soil Protection Act (LBodSchG NRW), the responsible Lower Soil Protection Authorities record harmful soil changes and suspected areas. For this purpose, they can create so-called soil contamination maps.

The former State Environmental Agency of North Rhine-Westphalia published the "Guideline for Creating Digital Soil Contamination Maps - Part I: Outdoor Areas" in 2000. Based on this, the digital soil contamination map (BBK) for the Oberbergischer Kreis was created in 2002 and 2005. It shows the widespread distribution of specific pollutants in natural topsoils outside built-up areas:

• Heavy metals: Arsenic (As), Cadmium (Cd), Lead (Pb), Copper (Cu), Nickel (Ni), Chromium (Cr), Mercury (Hg), Thallium (Tl), Zinc (Zn)

• Organic substances: Polychlorinated Biphenyls (PCB), Polycyclic Aromatic Hydrocarbons (PAH), Benzo(a)pyrene (BaP)

The measured or estimated substance concentrations are compared with the precautionary, testing, and action values of the Federal Soil Protection and Contaminated Sites Ordinance (BBodSchV). Evaluation maps are then created, showing areas where legal values are met or exceeded.

The soil contamination map serves as an indication and information system. It does not replace an investigation in individual cases.

Precautionary values 

If precautionary values are not exceeded, the soils are generally considered harmless. Exceeding these values does not necessarily indicate a concrete danger, but it does show that additional pollutant entries should be avoided. Property owners and users are obligated to take precautions against harmful soil changes (§ 7 Paragraph 1 BBodSchG).

Testing values 

If testing values are exceeded, there is suspicion of harmful soil changes or contamination. In such cases, the Soil Protection Authority examines the individual case more closely. 

Action values 

If action values are exceeded, harmful soil changes or contamination are generally present. Appropriate measures for hazard prevention must then be evaluated and implemented.

Notes on the use of maps

The soil contamination map has a scale of 1:50,000. It is therefore suitable only for a large-scale assessment. Statements about individual properties are limited. Proper interpretation of the data requires soil science expertise. You are welcome to contact the staff of the Lower Soil Protection Authority for professional assessment and inquiries.

Soil contamination with heavy metals in home gardens

The Oberbergischer Kreis naturally consists partially of ore-rich rock in the subsoil. Former ore mining, especially in Reichshof, Morsbach, and Engelskirchen, has led to increased heavy metal concentrations in the soils.
In hillside and mountainous areas, traces of mining, such as remnants of old pits, mines, and dumps, can still be found today. In the floodplains of the Agger and Wiehl rivers and their tributaries, soils are partially contaminated with cadmium, lead, zinc, and mercury. The areas particularly affected are Engelskirchen-Loope-Ehreshoven and Heidberg-Wildbergerhütte.
Since material from mining dumps was also used in road construction projects in the region, garden soils in areas near old pits and mines may also be contaminated with heavy metals.
To minimize human intake of heavy metals from contaminated garden soils, the district administration provides guidelines for the use of affected home gardens. These guidelines were published in the citizen notice "Recommendations for Heavy Metal-Contaminated Home Gardens." They are available for download.