Environmental investigations: URETEK expansion resins

URETEK expansion resins are FCWK- and formaldehyde-free. They also contain no radon. Consequently, no permit is required to apply the URETEK method.

The Dutch authorities have such confidence in our method and the materials used that we have even been permitted to carry out projects in sensitive nature reserves. This confidence in the environmental safety of our materials is underpinned, amongst other things, by a 2003 study by the German Hygiene-Institut:
Chemical/toxicological investigation of a two-component polyurethane system, URETEK Resin 2409
Hygiene-Institut des Ruhrgebiets, Gelsenkirchen (2003/2006).

Sampling (excerpt)

To test the injected and cured two-component polyurethane system for toxicity to plants, earthworms and bacteria, test pits were excavated in the area of a section of road to be raised in Gifhorn, northern Germany (the exact site plan is available to you); the PU foam materials obtained in this way covered, on the one hand, a depth profile (depth: 0.3 m – 0.8 m), in which the subsoil is predominantly filled with sand, and, on the other hand, an area (depth: = 0.8 m) containing peat.
In summary: the samples under investigation were not prepared specifically for this study, but originate from a project carried out in practice as part of a URETEK DeepInjection® project in Gifhorn, Germany.

Study design (quote)

The samples analysed were polyurethane foam samples which had cured in the subsoil for approximately one week prior to sampling and were mechanically crushed for laboratory analysis (particle size: 0 – approx. 3 mm). The polymerised and cured two-component polyurethane system ‘URETEK RESIN 2409’ from the two soil horizons (sample 1: depth 0.3 – 0.8 m and sample 2: depth = 0.8 m) was subjected to leaching tests in their original form or in the aqueous eluate obtained in accordance with DIN 38414, Part 4, with a view to determining growth inhibition in plants, assessing toxicity to earthworms and measuring light emission from bacteria (luminescent bacteria test); in addition, the water-soluble fractions of selected parameters, as well as the pH value, electrical conductivity and chemical oxygen demand (COD), were determined in the eluate (1 + 10).

In summary: the PU foam samples, which had cured in the ground for approximately one week prior to excavation, were partially mechanically ground in the laboratory to a particle size of 0 to approx. 3 mm. The original samples and the ground samples were subjected to a leaching test in accordance with DIN 38414 to investigate growth inhibition in plants, toxicity to earthworms and light emission by bacteria. In addition, the pH value, electrical conductivity and chemical oxygen demand were determined in the eluate (1 + 10).

Conclusions (quote)

In summary, taking into account the test results obtained, it can be concluded that the leachable constituents of the cured PU foam ‘URETEK RESIN 2409’ show no toxicity towards bacteria (Gl = 1).The polymerised and cured two-component polyurethane system ‘URETEK RESIN 2409’ is not toxic to earthworms (LC₅₀ (14 days) > 1000 g PU foam/kg soil). With regard to plant toxicity, it should be noted that a detectable inhibition of plant growth is only observed at weight ratios of 1000 g PU foam/kg soil. Radishes are the most sensitive. However, the determined IC₅₀ values determined, however, are several orders of magnitude higher than the mass concentrations specified in the EEC Directive 67/548/EEC, which, when assessing aquatic toxicity, would lead to a classification as toxic or harmful, so that labelling with R 54 (‘Toxic to plants’) is not warranted (comparable concentration values for soil are not specified in Annex VI, No. 5.2.2, of EU Directive 67/548/EEC).

In summary: it can be concluded that the material leached from ‘URETEK RESIN 2409’ is not toxic to bacteria and/or earthworms. With regard to toxicity to plants, it can be stated that growth disruption only occurs at a PU foam concentration of 1,000 grams per kilogram of soil. Radishes are the most sensitive. As the IC₅₀ values applied (foam-to-soil ratio) are so significantly above the value prescribed in EC Directive 67/548/EEC, it is clear that an R54 classification (toxic to plants) is absolutely not applicable in this case.