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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Calcium cyanamide and cyanamide are concluded to be readily biodegradable based on the following information:

Calcium cyanamide, technical grade (Kalkstickstoff) and cyanamide did not fulfill the criteria for ready biodegradability in standard tests according to OECD 301 B (CO2 evolution) and OECD 301 E (modified OECD screening test; Hoeck, 1988), respectively. However, a following study (Malta, 1990) showed that cyanamide was completely degraded within two weeks when it served as nitrogen source for degradation of a carbon-containing compound (sodium acetate), whereas the cyanamide degradation was rather slow when cyanamide served as both carbon and nitrogen source.

It can be concluded that the biodegradation of cyanamide and calcium cyanamide in a standard ready biodegradability test is prevented by the presence of another easily available nitrogen source.

But, as rapid degradation of cyanamide could clearly be demonstrated under environmentally realistic conditions in two aerobic water/sediment model systems (see IUCLID section 5.2.2) and in soil (see IUCLID section 5.2.3):

In two water/sediment systems, DT50 values of 2.5 days (river) and 4.8 days (pond) for the whole systems and half-lives of 2.3 days (river) and 4.3 days (pond) for the water phase were calculated for cyanamide. Elimination of [14C]-cyanamide from the water/sediment systems proceeded mainly via mineralisation to CO2. Only one major metabolite, identified as urea, was detected in the pond system. In the sediments, neither the parent substance nor degradation products were detected at significant amounts.

Cyanamide can thus be considered as rapidly degradable according to the CLP Regulation (EC) No 1272/2008, Annex I sections 4.1.2.9.2 and 4.1.2.9.3. Therefore, cyanamide (and calcium cyanamide in a read-across approach) were concluded to be "readily biodegradable".

In addition, the following DT50 and DT90 values were calculated for the aerobic and anaerobic degradation of cyanamide in soil under laboratory conditions: 

DT50 aerobic: 0.7–4.6 days

DT90 aerobic: 2.4–15.2 days

DT50 anaerobic: 34.7 days

DT90 anaerobic: 105 days

 

Additional information

Read-across from cyanamide to calcium cyanamide for the endpoints biodegradation in water/sediment and soil is justified, because calcium cyanamide is fast transformed to hydrogen cyanamide in aqueous solutions. Therefore, the fate in natural aquatic environments can be expressed in terms of cyanamide, irrespective of the substance constituting the exposure source, and read-across from cyanamide to calcium cyanamide is justified.

Thus, for industrial manufacture and use of calcium cyanamide, release of the substance to water will result in potential environmental exposure of hydrogen cyanamide. Any subsequent potential soil exposure via sludge and air will be by cyanamide, not calcium cyanamide.

(Please note: EUSES modelling (implemented in Chesar v3.3) indicates negligible soil exposure via sludge and air. Release percentages of the modelled biological STP directed to air and sludge are 3.81E-04 % and 0.168 %, respectively. Cyanamide is rapidly degraded in water/sediment and soil systems. Thus, rapid degradation of cyanamide is anticipated during storage of sewage sludge in digestion towers prior to soil application (if applicable), reducing the final concentration of hydrogen cyanamide in sludge to negligible values.)

For further information on read-across for environmental endpoints please refer to the document in IUCLID section 13.

For the agricultural application of calcium cyanamide the substance is formulated in a slow dissolving granule (PERLKA) that is applied to agricultural fields as a fertiliser. In contact with soil moisture, PERLKA granules will slowly release cyanamide. To determine the rate constants and DT50 values for the release of cyanamide from PERLKA and the subsequent degradation of cyanamide, two studies were conducted by Güthner (2018) and Weinfurtner (2019).

The DT50 values from these two studies were normalised to a standard temperature of 20 °C and to a standard soil moisture of pF 2 (= field capacity), if required by the respective model.Subsequently, these values were used as input for the exposure calculations of the predicted environmental concentrations in surface water, groundwater and soil in relation to the agricultural application of PERLKA which were performed with FOCUS Step 3 + Step 4, FOCUSPEARL, and ESCAPE V2.0, respectively.

An overview of the relevant DT50 input values per model is given below:

Exposure model

DT50 PERLKA [d]

DT50 cyanamide [d]

FOCUS Step 3 + 4

0.721

0.78

FOCUSPEARL

0.721

0.78

ESCAPE V2.0

0.740

0.766

 

Additionally, for one soil the content of the secondary transformation products of cyanamide, dicyandiamide (DCD), urea (CH4N2O), nitrate (NO3-), nitrite (NO2-) and ammonia (NH4+), at different sampling points was determined. In this additional experiment, the soil was treated with PERLKA respectively Cyanamid F1000 as described above but the extraction was always performed with deionised water. Urea, nitrate, nitrite and ammonia were determined by using ion chromatography, DCD by LC-MS/MS.  

The transformation from cyanamide to secondary transformation products depend on the tested material. Whereas for Cyanamid F1000 only urea and ammonia in larger amounts could be detected, for PERLKA also nitrate and DCD were determined. The observed nitrate is not a transformation product but represents the original amount of nitrate in PERLKA. The observations on the amounts of transformation products were comparable to former study results (e. g. Vilsmeier & Amberger, 1978).