Soil assessment - Threshold values for arsenic and heavy metals

Hello everyone,

we are quite close to purchasing our future building plot in a new development area of the municipality. Now I have had the already prepared soil report sent to me and after reading it, I am a bit uncertain. The attachment "chemical analysis" shows clear exceedances for arsenic, lead, chromium, copper, nickel, thallium, and zinc.



The development plan also states that in the area of the children's playground, due to the applicable limits for arsenic, the soil should be replaced. Our children are also supposed to play in our garden, and I want to plant vegetables...

By the way, the area is very natural (no industry or similar, small village); I cannot understand where the pollutants should be coming from.

What do you think – how should we deal with this? Does anyone know a source where I can look up the limit values?

Thank you very much for your answers!!

Hi! Just Google: Zuordnungswerte für Boden gem. LAGA

You will quickly find a table. Assignment values in solid matter and assignment values in eluate.

For arsenic it is stated that your value of 31 mg/kg corresponds to LAGA Z 1.1. That is the level above LAGA Z 0 (the best class).

Your lead value in the soil: would be LAGA Z0.

I will not go through all the values now.

First, get an idea yourself and check if a value is drastically too high. Of course, LAGA Z0 is great, but Z1.1 is still acceptable. The author of the report is surely known and could be asked.

Every soil contains certain amounts of contamination. Even in the countryside. How and when the substances could have gotten in there, I cannot say.

Best regards Thorsten

And worth mentioning again: this report from the municipality does not replace the soil report for your own property.

I once had almost the same experience; I nearly bought a plot of land that the city had described as harmless. The soil survey I commissioned showed very similar values to yours; it was also a rather rural location. I investigated further, and the solution to the mystery was an old, long-closed mine nearby where lead and zinc had been extracted. The necessary chemicals and remnants of the mining had seeped into the surroundings through rainwater as well as groundwater and slope water, etc. When I spoke to the responsible building authority about these results, they recommended (of course “just to be safe”) replacing at least 50 cm of the topsoil with new topsoil, not using that area as a kitchen garden, and preferably not letting small children play in the garden. Great, right? Despite the dream location and the favorable price, I didn’t buy the property. Maybe you could take a closer look at a map of the area; you might find an old mine there too.

Good luck and best regards

Susannchen

Great, isn't it? Despite the dream location and the affordable price, I did not buy the property. Maybe you should take a closer look at a map of the area; you might also find an old mine there.

Good luck and best regards

Susannchen

Hi,

1. A good and plausible explanation. Almost everywhere around here, there is an old mine lurking. Also here with us. I also found an old mining tool, certainly over 100 years old, during our groundworks... I will restore it at some point and put it in the garden as a "sculpture." My excavator operator knew the name for it back then, but I have forgotten it.

2. My personal opinion is: I would not purchase a property unless the soil is absolutely free of contaminants. After all, the house you want to live in for a long time is built on it.

3. The soil here with us was LAGA Z0. I assume that was the case because about 45 years ago, four very large high-rise complexes were built here, and a comprehensive soil exchange must have been carried out at that time (more precisely, see point 4: it was carried out). This new residential area emerged because the high-rises were all demolished as part of urban development. What is now my property used to be the playground of one of the high-rises.

4. Definitely ask the residents in the locations you are interested in. Especially older inhabitants sometimes know extremely well about the local past.
Personally, I was not too shy to just ring the doorbell of strangers in the area and ask a few questions. No one (!) slammed the door in my face; everyone provided information if they could and helped me.

PS: About the property seller, who acted really cleanly and authentically in all respects, I even later received an expert report from (some, hidden in the many folders) Mining Authority from Arnsberg. On many pages, the former mining situation was described and presented here. Presumably, this authority has such documents for almost all regions in NRW. However, I do not know if this costs anything. The document was made available to me free of charge.

This information was relevant to me at the time because I then knew that there was no legal or illegal tunnel under the house. Somehow important, because from time to time a house or garage in NRW/Ruhrgebiet suddenly just falls into a suddenly opening hole. Despite the always interesting reports about it: Nobody wants to deal with that.