Final opinion on potential risks to human health and the environment from the use of calcium cyanamide as fertiliser.
Date: 2017-03-03
Institutions: Directorate-General for Health and Food Safety
Subjects: ecologism, environmental impact, environmental standard, fertiliser, fertiliser industry, health risk, plant health treatment, public health, regulation (EU), toxic substance

Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Scientific Committee on Health and Environmental Risks 

SCHER 

Final Opinion 

on  

Potential risks to human health and the environment from the 
use of calcium cyanamide as fertiliser 

SCHER adopted this Opinion at its plenary meeting on 22 March 2016. 

1 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

About the Scientific Committees 

Three  independent  non-food  Scientific  Committees  provide  the  Commission  with  the 
scientific  advice  it  needs  when  preparing  policy  and  proposals  relating  to  consumer 
safety, public health and the environment. The Committees also draw the Commission's 
attention to the new or emerging problems which may pose an actual or potential threat.  

They are: the Scientific Committee on Consumer Safety (SCCS), the Scientific Committee 
on  Health  and  Environmental  Risks  (SCHER)  and  the  Scientific  Committee  on  Emerging 
and Newly Identified Health Risks (SCENIHR) and are made up of external experts.  

In addition, the Commission relies upon the work of the European Food Safety Authority 
(EFSA),  the  European  Medicines  Agency  (EMA),  the  European  Centre  for  Disease 
prevention and Control (ECDC) and the European Chemicals Agency (ECHA). 

SCHER 

This  Committee  deals  with  questions  related  to  pollutants  in  the  environmental  media 
and other biological and physical factors or changing physical conditions which may have 
a negative impact on health and the environment, for example in relation to air quality, 
waters, waste and soils, as well as on life cycle environmental assessment. It shall also 
address  health  and  safety  issues  related  to  the  toxicity  and  eco-toxicity  of  biocides.  It 
may  also  address  questions  relating  to  examination  of  the  toxicity  and  eco-toxicity  of 
chemical,  biochemical  and  biological  compounds  whose  use  may  have  harmful 
consequences  for  human  health  and  the  environment.  In  addition,  the  Committee  will 
address  questions  relating  to  methodological  aspect  of  the  assessment  of  health  and 
environmental  risks  of  chemicals,  including  mixtures  of  chemicals,  as  necessary  for 
providing sound and consistent advice in its own areas of competence as well as in order 
to contribute to the relevant issues in close cooperation with other European agencies. 

Scientific Committee members 
Alena Bartonova, Claire Beausoleil, María José Carroquino, Pim De Voogt, Raquel Duarte-
Davidson, Teresa Fernandes, Jadwiga Gzyl, Colin Janssen, Renate Krätke, Jan Linders, 
Greta Schoeters 

Contact: 

European Commission 
Health & Food Safety 
Directorate C: Public Health 
Unit C2 – Health Information and scientific committees 
Office: HTC 03/073  
L-2920 Luxembourg 
SANTE-C2-SCHER@ec.europa.eu 

© European Union
 ISSN 1831-4775  

ISBN 978-92-79-65679-8

DOI 10.2875/301668

EW-AR-17-001-EN-N

The Opinions of the Scientific Committees present the views of the independent scientists 
who  are  members  of  the  committees.  They  do  not  necessarily  reflect  the  views  of  the 
European Commission. The Opinions are published by the European Commission in their 
original language only. 

http://ec.europa.eu/health/scientific_committees/policy/index_en.htm

2 

Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

ACKNOWLEDGMENTS 

The members of the Working Group are acknowledged for their valuable contribution to 
this Opinion. They are: 

SCHER Working Group on calcium cyanamide: 

Prof. Pim De Voogt (Chair) 

Dr. Alena Bartonova 

Prof. Colin Jansen 

Dr. Jadwiga Gzyl 

Dr. Renate Krätke 

Dr. Jan Linders (Rapporteur) 

Prof. Greet Schoeters 

All Declarations of Working Group members and supporting experts are available at the 
following webpage: 
http://ec.europa.eu/health/scientific_committees/environmental_risks/members_commit
tee/index_en.htm 

3 

 
 
 
 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

ABSTRACT 

The  purpose  of  this  Opinion  is  to  assess  potential  risks  to  human  health  and  the 
environment from the use of calcium cyanamide as fertiliser. Where appropriate, data on 
hydrogen  cyanamide  were  also  considered  as  this  substance  is  a  primary  intermediate 
formed  by  the  degradation  of  calcium  cyanamide  when  applied  as  fertiliser  or  after 
organisms  have  been  exposed  to  it.  The  SCHER  has  collected  available  data  on 
physicochemical properties, agricultural practices and (eco) toxicology of this substance. 
These were used to derive an acceptable operator exposure level (AOEL) as well as the 
predicted no effect concentrations (PNECs). Subsequently the SCHER calculated predicted 
environmental concentrations (PECs) using the common application rates of the fertiliser 
and  exposure  models.  The  resulting  PECs  were  compared  to  the  PNECs  to  calculate  the 
risk characterization ratios (RCRs) for environmental compartments. 

With regard to human health, the SCHER has calculated human health risks using worker 
exposure  models  for  the  use  of  calcium  cyanamide  as  fertiliser,  based  on  approaches 
used for registration of plant protection products. Exposure calculations were performed 
for  both  professional  and  private  use  scenarios  and  additionally  for  by-standers  and 
residents, including children. 

The SCHER concluded that harmful effects for humans and for the environment could not 
be excluded when calcium cyanamide is used at the current rates of application. 

Keywords:  calcium  cyanamide,  fertiliser,  human  toxicity,  environmental  effects,  risk 
assessment 

Opinion to be cited as: 

SCHER  (Scientific  Committee  on  Health  and  Environmental  Risks),  Potential  risks  to 
human  health  and  the  environment  from  the  use  of  calcium  cyanamide  as  fertiliser,  22 
March 2016 

4 

 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

TABLE OF CONTENTS 

ABSTRACT .......................................................................................................... 4 

EXECUTIVE SUMMARY ........................................................................................... 7 

1. 

2. 

3. 

BACKGROUND ............................................................................................. 9 

TERMS OF REFERENCE ................................................................................ 10 

SCIENTIFIC RATIONALE .............................................................................. 11 

3.1. Introduction and scope .............................................................................. 11 

3.2. State-of-the-art ........................................................................................ 11 

3.2.5.1. 
3.2.5.2. 

3.2.1.  Some history on calcium cyanamide .................................................. 11 
3.2.2.  Basic compound properties .............................................................. 12 
3.2.3.  Production process and reactivity ...................................................... 13 
3.2.4.  Uses and way of application ............................................................. 14 
3.2.5.  Fate and behaviour in the environment .............................................. 19 
Transformation scheme .................................................... 19 
Environmental transformation rates in soil and water............ 20 
3.2.6.  Ecotoxicological assessment ............................................................. 23 
3.2.6.1.  Aquatic ecotoxicity .......................................................... 23 
Terrestrial ecotoxicity ....................................................... 24 
3.2.6.2. 
3.2.7.  Mammalian toxicology ..................................................................... 25 
3.2.8.  Operator, bystander and residential exposure estimates ...................... 31 
3.2.9.  Soil, groundwater and surface water, exposure estimates .................... 35 
Justification Pesticides model used for fertilisers .................. 35 
Estimated PEC in soil ....................................................... 36 
Estimated PEC in groundwater ........................................... 36 
Predicted Environmental concentration in surface water ........ 37 
Estimated concentration in air ........................................... 41 
3.3. Risk Assessment ....................................................................................... 41 

3.2.9.1. 
3.2.9.2. 
3.2.9.3. 
3.2.9.4. 
3.2.9.5. 

3.3.1.  Human Health Risk Assessment ........................................................ 41 
3.3.2.  Environmental Risk Assessment ....................................................... 42 
3.4. Conclusions on data .................................................................................. 46 

3.4.1.  Human health 46 
3.4.2.  Environment  47 
3.4.3.  Uncertainties  47 
OPINION OF THE SCHER ............................................................................. 49 

4. 

4.1. Question 1 of ToR ..................................................................................... 49 

4.2. Question 2 of ToR ..................................................................................... 49 

4.3. Question 3 of ToR ..................................................................................... 50 

4.4. Question 4 of ToR ..................................................................................... 50 

5 

 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

5. 

6. 

7. 

8. 

9. 

MINORITY OPINION .................................................................................... 51 

COMMENTING PERIOD ................................................................................ 52 

LIST OF TERMS AND ABBREVIATIONS ........................................................... 53 

REFERENCES ............................................................................................. 55 

ANNEXES .................................................................................................. 60 

Annex 1: EPISUITE results for calcium cyanamide ............................................... 60 

Annex  2:  Operator  exposure  calculations  using  UK  models  for  granular 

formulations ............................................................................................ 62 

Annex 3: Exposure during private use based on puffer pack model of the UK ........... 66 

Annex 4: Exposure calculation for bystander, residents and children ...................... 68 

6 

 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

EXECUTIVE SUMMARY 

The  purpose  of  this  Opinion  was  to  assess  potential  risks  to  human  health  and  the 
environment from the use of calcium cyanamide as fertiliser. 

Information has primarily been obtained from the dossier presented by the manufacturer 
to support its request for registration of the substance calcium cyanamide as a fertiliser 
in the European Union and the evaluation of the pesticide hydrogen cyanamide prepared 
by European Food Safety Authority (EFSA) in 2010. Other relevant scientific papers from 
the  literature  were  also  used  if  judged  relevant  with  regard  to  the  questions  asked. 
Where appropriate, data on hydrogen cyanamide were also considered as this substance 
is a primary intermediate formed by the degradation of calcium cyanamide when applied 
as fertiliser or after organisms have been exposed to it. 

The SCHER notes that no specific  risk assessment methodology has been developed for 
fertilisers  in  the  European  Union  that  could  be  applied  to  the  questions  posed  to  the 
SCHER. Therefore, the SCHER has chosen to apply, as far as possible, the methodology 
developed for the registration of plant protection products. 

The  SCHER  has  collected  available  data  on  physicochemical  properties,  agricultural 
practices  and  (eco)toxicology.  These  were  used  to  derive  an  acceptable  operator 
exposure  level  (AOEL)  as  well  as  predicted  no-effect  concentrations  (PNECs)  for  the 
environmental  risk  assessment.  Subsequently 
the  SCHER  calculated  predicted 
environmental concentrations (PECs) using the common application rates of the fertiliser 
and exposure models. The resulting PECs were compared to the PNECs to calculate risk 
characterisation ratios (RCRs). 

The  SCHER  addressed  potential  uncertainties  in  the  risk  assessment  that  relate  to  the 
use  of  exposure  models,  physicochemical  characteristics  of  the  particles  and  some 
missing data on chronic (eco)toxicity. However, the SCHER concluded that this does not 
influence the outcome of the risk assessment. Based on kinetic data available, the SCHER 
into  cyanamide  after  oral 
concluded 
administration to experimental animals, as well as to humans, as a result of hydrolysis, 
and  that  toxic  effects  observed  for  calcium  cyanamide  were  mainly  attributable  to 
cyanamide toxicity. The SCHER adopted a lowest observed adverse effect level (LOAEL) 
of  1.3  mg  calcium  cyanamide/kg  bw/d  based  on  a  published  rat  study  and  derived  a 
provisional AOEL of 4.3 µg/kg bw/d using a safety factor of 300. 

that  calcium  cyanamide 

transformed 

is 

With  regard  to  human  health,  the  SCHER  has  calculated  human  exposure  using  worker 
exposure  models.  The  use  of  calcium  cyanamide  as  fertiliser  was  based  on  data 
measured  for  inhalatory  exposure  as  well  as  on  default  values  attributed  to  exposure 
calculation  models  judged  appropriate  for  granulated  materials.  Exposure  calculations 
were  performed  for  both  professional  and  private  use  scenarios  and  additionally  for 
bystanders and residents, including children. 

For  the  environmental  risk  assessment,  the  SCHER  derived  a  PNECshort-term  value  of  60 
µg/L  for  the  aquatic  environment,  based  on  an  assessment  factor  of  100  and  a  lowest 
reported  48h-EC50  of  6  mg/L  (using  ecotoxicity  data  for  three  distinct  taxonomic 
groups). For the terrestrial environment a PNEC of 17.3 mg/kg soil dw was derived from 
earthworm toxicity data using an assessment factor of 10. 

Based  on  available  data  the  SCHER  has  estimated  the  PECs  in  soil,  groundwater  and 
surface water using the  FOCUS scenario approach  originally  designed for the  evaluation 
of pesticides. 

7 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

The  SCHER  concluded  that  harmful  effects  for  humans  and  for  the  environment  cannot 
be  excluded.  Risks  were  identified  for  the  end-users  (farmers,  as  well  as  private  users) 
and  for  residents  and  bystanders  including  children,  if  the  formulation  with  calcium 
cyanamide  as  the  fertilising  agent  was  applied  at  the  recommended  dose  of  450  kg 
a.s./ha in the realistic worst case and 225 kg a.s./ha in the normal case. In addition, the 
SCHER identified risks for the contamination of the aquatic environment. 

Recommendations  for  protective  measures  provided  by  the  manufacturer  are  not 
considered sufficient to ensure a safe application of calcium cyanamide for the operator. 
It  is  unlikely  that  additional  measures  will  lead  to  safe  use  for  the  operators  due  to 
increased  inconveniences  experienced  during  application.  Furthermore,  no  protective 
measures are available for bystanders and residents who are also exposed. Private use of 
calcium cyanamide as fertiliser is not recommended by the SCHER. 

To  reduce  the  risk  to  the  aquatic  compartment  to  a  RCR  <  1,  the  most  common 
application rate of calcium cyanamide needs to be lowered by a factor of 56. Similarly the 
reduction factor needed for protecting the soil environment would have to be 17. 

The SCHER was also asked to identify major gaps in scientific knowledge. Gaps identified 
are described in paragraph 4.4. 

8 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

1.  BACKGROUND 

On 8 March 2013, DG ENTR requested DG SANCO to consult the SCHER for its opinion on 
the  potential  risks  for  human  health  and  the  environment  from  the  use  of  calcium 
cyanamide  as  fertiliser.  In  May  2014,  the  SCHER  delivered  an  Opinion  to  the 
Commission,  and  gave  the  company  manufacturing  the  substance  the  opportunity  to 
comment  on  the  Opinion  by  the  end  of  July  2014.  In  September  2014,  the  company 
submitted  a  revised  chemical  safety  report  to  ECHA  in  the  context  of  the  REACH 
Regulation. 

DG GROW asked the company to list all the relevant available background information in 
its possession for the finalisation of the SCHER Opinion. A cut-off date of 31.03.2015 for 
submission of new data was accepted by the company. 

Following receipt of the information provided by the company on the date of 31.03.2015, 
the data were submitted to the SCHER for its assessment. 

The SCHER is asked now to re-evaluate two main issues in this assessment: 

(1)  the  application  rates  used  should  be  based  on  consumer  instructions  or 
recommendations, provided by the company to DG GROW before 1 April 2015 and 

(2)  the  choice  of  assessment  model  shall  clearly  be  justified  in  the  SCHER  Opinion. 
Furthermore,  the  use  and/or  calculation  of  model  parameters  should  be  explained  and 
justified: in particular, this applies to threshold values (which type of value, selection and 
interpretation of underlying toxicity test, assessment factor), the dermal absorption rate, 
the  inhalable  fraction,  the  particle  size  and  any  other  parameters  that  the  SCHER  may 
identify in the course of its assessment as being relevant. 

9 

 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

2.  TERMS OF REFERENCE 

The SCHER is requested to answer the following questions: 

1.  Taking into account all relevant information that is available before 1 April 2015, 
can the use of both the powdered and granulated form of calcium cyanamide be 
considered safe for human health and the environment? 

2.  In  case  of  risks  identified  by  the  SCHER,  are  the  protective  measures 
recommended  by  the  manufacturer  sufficient  to  ensure  a  safe  use  of  calcium 
cyanamide as fertiliser? 

3.  In case of potential risk for the environment, which application rate per concerned 
crops would not create any detrimental effect under the relevant soil and climatic 
conditions? 

4.  In  case  major  gaps  are  identified  in  the  scientific  knowledge  of  the  hazard  or 
exposure  associated  with  the  use  of  calcium  cyanamide,  how  does  the  SCHER 
suggest closing those gaps within a reasonable period of time? 

10 

 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

3.  SCIENTIFIC RATIONALE 

3.1. Introduction and scope 

In  order  to  be  able  to  answer  the  questions,  the  SCHER  studied  the  extensive  REACH 
dossier  presented  by  the  manufacturer  to  support  its  request  for  registration  of  the 
substance  calcium  cyanamide  as  a  fertiliser  in  the  European  Union.  The  SCHER  also 
assessed several papers from the scientific literature. The Committee reviewed these and 
made  an  inventory  of  the  documentation  before  preparing  the  Opinion.  The  SCHER 
selected the main documents from the literature to underpin the Opinion with respect to 
the  questions  asked.  Therefore,  the  SCHER  took  only  into  account  the  papers  and 
documents  that  related  directly  to  the  problem  posed.  Other  documents  have  been 
judged  and  evaluated  by  the  SCHER  as  being  of  secondary  usefulness  compared  to  the 
documents  of  main  importance.  Basic  documents  used  were  the  dossier  (AlzChem 
Trostberg, 2010 and Pusch, 2014) presented by the manufacturer and the evaluation of 
the  pesticide  hydrogen  cyanamide  prepared  by  the  European  Food  Safety  Authority  – 
EFSA (EFSA, 2010). 

In  April  2015,  DG  GROW  submitted  new  Terms  of  Reference  requesting  the  SCHER  to 
take into account the revised registration dossier (SCC, 2015). 

Section  3.2  of  the  SCHER  Opinion  presents  the  knowledge  available  on  the  physico-
chemical properties of the substance, including its fate and behaviour, the intended use 
of the substance in the formulation as a fertiliser and an overview of the toxicological and 
ecotoxicological information. Section 3.3 presents the risk assessment based on the final 
selection  of  the  data,  whilst  section  3.4  provides  a  summary  of  the  results.  Finally, 
Chapter 4 presents the opinion of the SCHER with respect to the questions asked. 

For some endpoints, studies on calcium cyanamide are limited. Additionally, some of the 
studies were not performed in line with internationally accepted test guidelines and are in 
many  cases  not  publicly  available.  The  SCHER  focussed  on  data  and  information  on 
kinetics  and  toxicity  of  calcium  cyanamide  but,  if  appropriate,  data  on  cyanamide  were 
also considered. All data were evaluated with regard to reliability, relevance and scientific 
validity  according  to  internationally  accepted  criteria.  Data  considered  being  of  the 
highest reliability included data from studies carried out according to valid, internationally 
or  nationally  accepted  testing  guidelines  -  preferably  performed  according  to  Good 
Laboratory Practice (GLP) - or in which all parameters described were closely related and 
comparable to a guideline method. In addition peer-reviewed information was taken into 
account. Data were used for an overall weight of evidence approach. 

3.2. State-of-the-art 

3.2.1.  Some history on calcium cyanamide 

Calcium  cyanamide  which  comprises  44%  calcium  and  24%  nitrogen  was  first  made  in 
the  late  1800s,  as  part  of  a  search  for  a  high  analysis  nitrogen  source  for  industry  and 
agriculture to replace low analysis (1 - <12%) excreta deposits. It is produced in 1,000 
to  >3,000°C  electric  arc  furnaces  by  burning  black  coal  and  white  limestone  in  the 
presence  of  atmospheric  nitrogen.  Energy  costs  represent  the  bulk  of  the  cost  of 
production of calcium cyanamide. The main use of calcium cyanamide is in agriculture as 
a fertiliser. Because calcium cyanamide is in general slow acting, one application at a rate 
of about 1,000 kg/ha, according to the application information (worst case) can last the 
length of the growing season. However, when calcium cyanamide is applied at this rate, 
11 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

particularly in cool and/or dry conditions, it is necessary to delay planting until the high 
concentrations  of  plant-penetrating  initial  hydrolysis  products  of  calcium  cyanamide, 
which are phytotoxic, dissipate. The phytotoxic characteristics of calcium cyanamide also 
make repeated dry applications at lower rates impractical. The observation that calcium 
cyanamide  exhibits  phytotoxicity  led  to  its  use  as  a  herbicide  (Hartmann,  2000).  The 
SCHER  focuses  its  considerations  on  doses  recommended  in  manufacturer's  information 
sheets taking an application rate of 1,000 kg of formulation/ha as a realistic worst case 
scenario and 500 kg/ha as a normal scenario. 

3.2.2.  Basic compound properties 

General data: 

- 

- 

- 

- 

- 

- 

Name: calcium cyanamide. 

Other names: cyanamide  calcium  salt,  Kalkstickstoff,  Lime  Nitrogen,  Nitrolime, 
calcium carbimide 

Molecular formula: 

CaCN2  

Molecular structure:   

 [NCN]2-   Ca2+; [Ca2+] [-N=C=N-] 

Molecular weight: 

80.11 g/mol 

CAS Number:  

156-62-7 

Relevant physico-chemical properties: 

- 

- 

- 

- 

- 

- 

Melting range (according DIN 51004): 1145 to 1217°C, 1340°C (EpiSuite 3.10) 

Density pure: 2.36 g/cm3 at 25°C 

Water solubility: 29.4 g/L at 20°C, 19.3 g/L at 25°C; pH of aqueous solutions are 
strongly alkaline 

log Pow: -0.20 for CaCN2 (calculated with EpiWin 3.10). 

Vapour pressure (mm Hg, 25°C) 4.58E-19 (EpiSuite 3.10) or 0 Pa 

Adsorption/desorption: The log Koc was measured to be <1.25 at pH 5.5 and 7.5. 
This  was  equivalent  to  a  Koc  of  17.8  dm3/kg.  The  corresponding  Kom  was  10.5 
dm3/kg. 

Calcium cyanamide is a white solid. Calcium cyanamide technical grade is a solid grey to 
black  powder  with  a  characteristic  odour  at  20°C  and  1,013  hPa.  In  granular  form  the 
product is known as PERLKA. Industrial-grade calcium cyanamide contains, in addition to 
CaCN2, ca. 20% CaO and 10 – 12% free carbon, which gives the product its grey-black 
colour. It can also contain a small amount of nitrides formed from silica and alumina. The 
total  nitrogen  content  varies  from  22  –  25%,  depending  on  the  raw  materials  used.  Of 
the total nitrogen, 92 – 95% is present as cyanamide and 0.1 – 0.4% as dicyandiamide; 
the remainder is present as nitrides (Güthner and Mertschenk, 2006). 

The  silica  and  alumina  nitride,  dicyandiamide,  and  other  minor  impurities  are  not 
expected  to  contribute  to  the  toxicological  properties  of  the  formulations,  thus  it  was 
justified  to  treat  the  substance  as  mono-constituent.  The  formulation  PERLKA  has  a 
calcium cyanamide content of 44 to 45%. The SCHER used a content of 45% in PERLKA 
as  PERLKA  accounts  for  98.5  %  of  all  calcium  cyanamide  fertilisers  sold.  Other 
environmentally  relevant  properties  of  calcium  cyanamide  are  discussed  in  the  sections 
below. 

12 

 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

PERLKA  is  a  solid,  granular  formulation  and  has  a  typical  particle  size  distribution  as 
shown in Table 1 (AlzChem Trostberg, 2010). 

Table 1: Typical particle size distribution of PERLKA (AlzChem Trostberg, 2015). 

No. 

#1 
#2 
#3 
#4 
#5 
#6 
#7 
#8 

Size 
(µm) 

<160 
<315 
<500 
<1000 
<1700 
<2500 
<3550 
>3550 

Cumulative 
Distribution 
(%) 
0.1 
0.2 
0.3 
1.5 
23.5 
71.6 
99.3 
100 

From these data the median particle diameter  was established at 2100  µm. The SCHER 
selected a fraction of 0.2 percent as the relevant drift percentage for the calculations for 
human  exposure,  taking  into  account  the  values  in  Table  1  and  also  the  information 
available in the CSR report. 

Wherever  relevant  the  SCHER  used  these  physico-chemical  characteristics  in  the 
calculations carried out. 

3.2.3.  Production process and reactivity 

Calcium cyanamide or CaCN2 is formed when calcium carbide reacts with nitrogen: 

CaC2 + N2 → CaCN2 + C 

There  is  only  one  manufacturer  of  calcium  cyanamide-containing  fertilisers  in  the 
European Union (EU). 

When  calcium  cyanamide  dissolves  in  water  it  produces  calcium  ions  (Ca2+)  and 
cyanamide  ions  (NCN2-)  as  products.  The  cyanamide  ion  is  very  basic  and  reacts  with 
water  to  form  the  acid  cyanamide  ion  (HNCN-).  The  acid  cyanamide  ion  is  amphoteric, 
i.e.  it  can  act  as  either  an  acid  or  a  base.  When  it  acts  as  an  acid  it  will  revert  to  the 
cyanamide  ion  and  when  it  acts  as  a  base  it  will  react  to  form  molecular  cyanamide 
(H2NCN). The form that cyanamide takes in solution depends on the pH of the solution, 
but molecular cyanamide is favoured at pH values typically measured in soils. Molecular 
cyanamide  can  then  undergo  hydrolysis  to  form  urea,  which  can  further  react  to  form 
ammonium  ions,  which  in  turn  can  be  converted  to  volatile  ammonia  or  to  nitrate.  The 
acid  cyanamide  ion  is  available  to  plants  and  organisms.  Once  absorbed  by  plants,  the 
acid cyanamide ion lasts only 2-4 h before it forms urea, which can stay in this form for 
4-8 h (Hartmann, 2000). 

In contact with water calcium cyanamide decomposes and liberates ammonia: 

CaCN2 + 3 H2O → 2 NH3 + CaCO3 

Through  hydrolysis,  calcium  cyanamide  produces  cyanamide  and  lime  (CaCO3),  which 
can in turn proceed to the formation of CaO: 

CaCN2 + H2O + CO2 → CaCO3 + H2NCN 

13 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

CaCN2 + H2O → (CaO + H2NCN)+ CO2 → CaCO3 + H2NCN 

In the human body, the hydrolysis of calcium cyanamide is thought to proceed as follows 
(Brien and Loomis, 1983): 

2 CaCN2 + 2 H2O → Ca(HNCN)2 + Ca(OH)2 

Ca(HNCN)2 + 2 H2O → 2 H2CN2 + Ca(OH)2 

The hydrogen cyanamide can further react with water to produce urea: 

H2CN2 + H2O → (H2N)2CO 

Calcium  cyanamide  is  stable  and  does  not  decompose  if  stored  normally  in  dry 
conditions.  If  in  contact  with  water,  ammonia  and  ethyne  gas  can  be  formed  (Scottish 
EPA, 2014). 

During the process of decomposition of lime-nitrogen in the soil, dicyandiamide (DCD), a 
nitrification  inhibitor,  was  formed  by  dimerization  (Nagumo,  et  al.,  2009).  Therefore, 
lime-nitrogen  application  could  mitigate  nitrous  oxide  (N2O)  emission  from  the  soil 
(Yamamoto, et al., 2012). See scheme in section 3.2.5. 

3.2.4.  Uses and way of application 

Two  formulations  containing  calcium  cyanamide,  i.e.  the  granulate  (PERLKA  =  Pearled 
calcium  cyanamide)  and  the  powder  (Kalkstickstoff),  are  sold  in  the  EU.  Under  normal 
use  conditions,  one  application  per  year  per  crop  is  required.  A  small  part  of  the 
granulate  produced  is  packed  by  retailers  in  5  kg  bags  for  private  use.  The  maximum 
frequency of application for private use is 2 – 3 per year. 

Calcium  cyanamide  is  used  in  agriculture  and  horticulture  predominantly  in  Europe  and 
Asia  as  a  slow-release  nitrogen  fertiliser  which  exhibits  side  effects  against  soil  borne 
plant  diseases,  slugs,  and  germinating  weeds.  The  fertiliser  is  broken  down  by  soil 
moisture  into  highly  reactive  lime  and  free  cyanamide.  The  latter  is  responsible  for  the 
fertiliser's  fungicidal  and  herbicidal  effects.  Within  a  few  days  after  application,  soil 
microbes and/or fungi, e.g. Myrothecium verrucaria (Maier-Greiner, et al., 1991) convert 
the cyanamide to urea and then to ammonia. Calcium cyanamide has to be applied prior 
to  sowing  and  so-called  deep  placement  in  soil  (at  20  cm  depth)  has  been  advocated 
(Kaushal, et al., 2006a). 

A  second  known  breakdown  pathway  leads  to  the  production  of  dicyandiamide,  which 
acts  as  a  nitrification  inhibitor  in  soil.  In  this  way,  the  conversion  of  ammonia  nitrogen 
into  nitrate  is  slowed  down  for  several  weeks  (Kaushal,  et  al.,  2006b),  and  leaching  of 
fertiliser nitrogen is prevented. Calcium cyanamide is claimed to be particularly valuable 
for  intensively  used  soils  that  are  highly  infested  with  soil  borne  pathogens  that  cause 
root and stem rot (Scottish EPA, 2014; Bourbos, et al., 1997; Shi, et al., 2009). Addition 
of  CaCN2  during  cow  manure  composting  significantly  shortens  the  time  to  inactivate 
foodborne pathogens (Simujide, et al., 2012). 

Recent developments in urea fertilisers have used a calcium cyanamide core within urea 
granules  to  stabilise  nitrogen  against  nitrification.  Calcium  cyanamide  is  also  used  to 
control animal pests on pasture. When applied to grassland, it kills the dwarf water snail, 
which  is  the  intermediate  host  of  the  liver  fluke.  It  also  kills  eggs  and  larvae  of  gastric 
and  intestinal  parasites  in  the  grass  and  controls  Salmonella  in  liquid  sewage  (Güthner 
and  Mertschenk,  2006).  In  considering  these  side  effects,  the  SCHER  is  of  the  opinion 

14 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

that the substance calcium cyanamide in itself should be evaluated as a pesticide.  This 
has not been done before, since no manufacturer supports this use. 

The SCHER is aware of the existence of two formulations, a powdered and a granulated 
form  which  have  different  particle  size  distributions.  As  the  information  on  the  particle 
distribution (see Table 1) is only available for the granulated form, the SCHER based its 
evaluation on the granulated form. 

As  a  consequence,  the  SCHER  used  different  exposure  assessment  approaches  for 
formulations  that  were  spread  by  spraying  from  a  device  mounted  on  a  tractor  for 
professional use or by spreading the granules by hand in the garden for private use. The 
main  difference  was  that  the  emission  of  calcium  cyanamide  to  surface  water  did  not 
occur  by  drift  but  only  by  runoff  or  drainage  in  the  second  case.  The  active  substance 
hydrogen cyanamide as evaluated by EFSA (EFSA, 2010a) is a formulation using water as 
a solubilising agent that was spread on land. The environmental risk assessment as well 
as the human exposure assessments for both forms of this substance could therefore not 
directly be compared in this Opinion or in the EFSA document (EFSA, 2010b). 

Application  of  calcium  cyanamide  may  lead  to  reduced  emission  of  N2O  (Hirono  and 
Nonaka,  2014,  Yamamoto,  et  al.,  2013)  as  a  result  of  the  inhibition  of  nitrification  by 
dicyandiamide, which is formed in the soil.  

Cyanamide  itself  has  been  shown  to  be  a  natural  product  that  can  be  found  in  vetch 
(Vicia villosa subs. varia Roth) and is known to suppress growth of weeds (Kamo, et al., 
2003). It is considered an allelochemical (Soltys, et al., 2011). 

Calcium  cyanamide  has  also  been  used  therapeutically.  It  is  known  to  inhibit  the 
endogenous  formation  of  oxalic  acid  by  inhibiting  the  conversion  of  glycolaldehyde  to 
glycolic  acid.  For  this  reason  it  has  been  used  with  varying  success  in  the  treatment  of 
primary hyperoxaluria (oxalosis). The main therapeutical use, however, is as a so-called 
anti-alcohol, or alcohol-sensitising drug in the treatment of chronic alcoholism as calcium 
cyanamide  interferes  with  the  hepatic  biotransformation  of  ethanol  by  inhibiting  the 
aldehyde  dehydrogenase  enzymes.  In  humans,  the  increased  blood  acetaldehyde 
concentration has been correlated with several physiological changes (MAK Commission, 
1979). 

For  some  EU  countries  examples  are  given  of  the  different  crops  with  associated 
application rates of PERLKA (Table 2). 

Table 2 Recommended application rates of PERLKA in some EU countries 

ITALY 
From Vegetable leaflet – translation 
Crop 

Dose 
kg/ha 
PERLKA 

Period 

Remarks 

Carrots, spinach, celery, 
fennel 
Garlic, onions, leeks 
Cabbage, cauliflower, broccoli 
Melon, watermelon, zucchini  
Eggplants, cucumbers 
Potatoes 
Tomatoes, pepper 

400 – 500  8 – 10 days 

before the sowing/planting 

400 – 500  8 – 10 days  
400 – 500  8 – 10 days 
400 – 500  8 – 10 days 
400 – 500  8 – 10 days  
350 – 400  7 – 8 days 
350 – 400  7 – 8 days  

before the sowing/planting 
before the sowing/planting 
before the sowing/planting 
before the sowing/planting 
before the sowing 
before the planting 

15 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Green beans, beans 
Artichoke 

250 – 300  5 – 6 days  
350 – 400  15 days 

before the sowing 
before the restart of the 
growth 

BENELUX 
From Vegetable leaflet BENELUX –translation 
Crop 

Period 

Dose 
kg/ha 
PERLKA 
300 – 500 

Potatoes 

Asparagus 

400 – 500 

Remarks 

Before planting or after planting until just 
before emergence 
after the cutting, when ploughing the beds 
and as long as the asparagus fields can be 
driven through without damaging the 
plants 

Pickles 
Beans 

Peas 

300 – 500  2 – 3 weeks  before sowing or planting 
200 – 300  1 – 2 weeks  before sowing or after sowing until shortly 

before emergence 

200 – 300  1 – 2 weeks  before sowing or from emergence to about 

Cabbage crops 

500 – 
1000 

2 weeks 

10 cm height 
against club root: before planting 500 

kg/ha and after planting 
500 kg/ha 

2 weeks 

against weeds: until 500 kg/ha 2 weeks 
before planting or 500 
kg/ha after planting 

Comment: after planting on Chinese cabbage and 

cauliflower max. 350 kg/ha 

Leeks 
Rhubarb 
Red radish 

300 – 500  before sowing or planting or 2 – 4 weeks after planting 
in spring before restart of the growth 
400 – 500 
400 – 500  8 – 10 days before sowing or planting 

Radish 

300 – 500 

Incorporation 5 – 10 cm into the soil, if needed keep the 
soil moist for some days 
in spring 2 to 3 weeks before sowing, in summer 1 week 
before sowing 

Ramenas (Raphanus 
sativus subsp. niger) 
Salsify 
Celery 
Lettuce 

Spinach 
Tomatoes 
Onions 

300 – 500 

before planting 

in spring 2 to 3 weeks before sowing, in summer 1 week 
before sowing 
200 – 300  3 – 4 weeks  before sowing 
400 – 500  3 weeks 
300 – 500 

lettuce until 400 kg/ha PERLKA, 2 – 3 weeks before 
planting 
lamb’s lettuce up to 500 kg/ha PERLKA, 2 – 3 weeks 
before planting 
300 – 500  2 – 3 weeks  before sowing 
400 – 500  3 weeks 
before planting 
300 – 500  2 – 3weeks  before sowing or as top-dressing for well–

Fennel 

300 – 400  2 – 3 weeks  before sowing or 300 kg/ha as top-

developed plants (5 – 10 cm) 

dressing on hand high crops 

16 

 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

in light soils use always the lowest dose 

top-dressing with PERLKA granular calcium cyanamide is only possible on dry plants, 
preferentially when the soil itself is still moist. 
GERMANY 
From Vegetable leaflet – translation 
Crop 

Period  Remarks 

Dose 
kg/ha 
PERLKA 

Rape 

200 – 250  autumn 

200 – 400  spring 

just before sowing or at the 4–leaf 
stage 
after a starter-fertilisation with an N 
/ S fertilizer as the second N 
application on the dry stock 

Winter crops 

200 

autumn  directly before sowing or after 

Summer crops 

200 – 400  spring 
200 – 300 

Corn 

300 – 500 

Potatoes 

Sugar beets 

Sunflower 

150 

300 – 500 
60 – 100 
300 – 500 

60 – 100 
250 – 300 

Fruit trees, vines 

200 – 400 

Hop 
Grassland and meadows 

300 – 400 
300 – 400 

SLOVAKIA 
From vegetable leaflet - translation 
Crop 

Rape 

Winter cereals 

Dose 
kg/ha 
PERLKA 
200 – 300 
300 – 400 

200 – 250 
250 – 300 

17 

emergence or at the 3–leaf stage 
at the end of tilling 
incorporate superficially before 
sowing or after emergence or from 
3–leaf stage to tilling,  
for malting barley only before 
sowing! 
incorporate superficially before 
sowing or between sowing and after 
emergence  
root-level placement alone or mixed 
with DAP 
Before planting  
Before emergence 
Approximately 14 days before 
sowing 

at 20 to 30 cm height spread on the 
dry stock 
In early spring until shortly before 
sprouting 
Before uncovering and cutting 
Early spring on the dried sod, 14 
days waiting time to grazing! 

Remarks 

Basic fertilisation before seeding by 
incorporation into soil 
Regenerative fertilisation 
Basic fertilisation before seeding by 
incorporation into soil 
Regenerative fertilisation 

 
 
 
 
 
 
 
 
 
 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Spring cereals 

Corn 

Peas 

Beans 

Bush beans 

Lettuce 

Valerianella locusta 

Carrots 
Spinach 
Cucumbers 

250 – 300 

100 – 150 
300 – 400 

200 – 300 

200 – 300 

300 – 400 

200 – 500 

300 – 500 

300 – 400 
300 – 500 
300 – 600 

Leeks, chives 

300 – 600 

Celery, tomatoes,  
Fennel  
Cabbage  family  (Brassicaceae) 
(while  cabbage,  red  cabbage, 
kale, 
(Brussels) 
sprout 

cauliflower, 

600 – 1000 
300 – 400 
300 – 1000 
300 – 400 

Radish 

Asparagus 

Onion 
Spring onion  

300 – 500 

400 – 500 

300 – 500 
300 – 500 

18 

Basic fertilisation before seeding by 
incorporation into soil 
By seeding under the base 
Before seeding by incorporation 
into soil 
1 – 2 weeks before seeding or from 
germination to approximately 10 
cm of the plant height 
1 – 2 weeks before seeding or after 
seeding until shortly before 
germination 
In between seeding and 
germination 
In spring 2 – 3 weeks, in summer 1 
week before planting 
2 – 3 weeks before seeding, by 
container planting 1 week before 
the planting 
2 – 3 weeks before seeding 
2 – 3 weeks before seeding 
Always 2 – 3 weeks before 
planting, also as row fertilisation 
before putting foil down. Attention 
when used after putting down foil, 
the plants must not come in 
contact with calcium cyanamide 
2 – 3 weeks before seeding or 
planting or 300 – 500 kg after 
germination 
3 weeks before planting 
2 – 3 weeks before seeding 
In spring around 3 weeks, in 
summer 1 week before 
planting/seeding. As the main 
fertiliser for dry plants (not for 
Chinese cabbage), after 
germination until rows are covered 
In spring 2–3 weeks, in summer 1 
week before seeding 
immediately after germination of 
weeds until asparagus is accessible 
without the risk of damage. As 
fertiliser into rows to heap up 
before covering. 
2 – 3 weeks before seeding or at 
the germination (from 5 – 10cm of 
the plant height) or 2 – 3 weeks 
after plantation evenly applied on 
the plant bed. 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Rhubarb 
Strawberries 

400 – 800 
300 – 500 

Potatoes 

300 – 500 

The plants must be absolutely dry. 
Early in spring before sprouting  
14 days before planting or after 
picking. In spring on dry plants 
300kg/ha or 500kg/ha after picking 
For reduction of nematodes 
(wireworms) before preparing 
hillocks (when it's dry already 
before planting). For protection 
against weeds from planting until 
shortly before germination: apply 
on mounds of dirt during the time 
of the biggest weed growth. 

Based  on  the  information  presented  in  Table  2,  the  SCHER  concludes  that  a  dosage  of 
1000 kg PERLKA/ha is recommended for a few crops in The Netherlands and in Slovakia 
and  therefore  the  SCHER  has  decided  to  use  this  as  realistic  worst  case  scenario.  The 
SCHER uses an application rate of 500 kg PERLKA/ha as the normal dosage. 

The  SCHER  selects,  for  human  exposure,  a  drift  percentage  for  granulated  calcium 
cyanamide of 0.2 % based on information in the new CSR and considers this value to be 
realistic. This percentage is reported to cover particles up to 200 µm. For environmental 
exposure it is common practice in the evaluation of Plant Protection Products to estimate 
the  drift  of  granular  formulations  to  the  environment  to  be  0%.  Therefore,  the  SCHER 
agrees  with  this  value  for  fertilisers  in  this  case  and  has  subsequently  used  it  in  this 
evaluation. 

3.2.5.  Fate and behaviour in the environment 

The substance, incorporated within a formulation, is applied on the agricultural field as a 
fertiliser. The SCHER has assumed that the formulation is applied to the field by a tractor 
mounted with suitable equipment to distribute the formulation equally. After application 
there  are  two  possibilities  for  further  action:  1)  the  formulation  is  superficially 
incorporated  in  the  soil  to  prevent  runoff  or  2)  the  formulation  is  incorporated  in  the 
upper 20 cm of the soil to allow slow release of the active substance, calcium cyanamide 
(Tewari, et al., 2004). 

3.2.5.1.  Transformation scheme 

The  possible  transformations  of  calcium  cyanamide  in  the  environment  are  summarised 
in Figure 1. 

19 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Figure 1 Scheme presenting possible transformation routes of calcium cyanamide in the 
environment. (modified from Klasse, 1996) 

The  SCHER  considered  that  the  most  important  degradation  route  was  the  hydrolytic 
pathway leading to hydrogen cyanamide, followed by further hydrolysis to urea: 

CaCN2 + H2O + CO2 → CaCO3 + H2CN2 

H2CN2 + H2O → (H2N)2CO  

3.2.5.2.  Environmental transformation rates in soil and water 

Abiotic degradation 

Calcium  cyanamide  hydrolyses  very  rapidly  to  hydrogen  cyanamide.  Results  from  a 
hydrolysis study at pH 1.2 and 5 showed that hydrogen cyanamide was released from its 
calcium salt within a few minutes (AlzChem Trostberg, 2010). 

Phototransformation  data  are  available  only  for  the  hydrolysis  product  (hydrogen 
cyanamide) in soil and water (Limacher, 2009), and details are provided below. 

In soil, with DT50 values (single first order) of 2.4 and 2.0 h in irradiated samples and in 
the dark, respectively, cyanamide degraded quickly in both types of tests, indicating that 
the degradation was caused by biodegradation. The rate of degradation due to photolysis 
was  negligible  compared  to  that  caused  by  biodegradation.  Cyanamide  was  almost 
completely mineralised to CO2 over the study period. Bound residues were < 5 % at the 
end  of  the  study  period.  No  major  metabolites  of  cyanamide  were  encountered  in  the 
higher tier soil photolysis study. (AlzChem Trostberg, 2010). 

In another study for cyanamide, DT50 values of 1.45 d (irradiated samples) and 4.22 d 
(dark control) were observed (Burri, 2000). 

20 

 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

In water, photolysis has been calculated to be slower with half-lives of 29 d (pH=5) and 
38 d (pH=7); in the dark: >100d (AlzChem Trostberg, 2010). 

Biodegradation in water and sediment 

Results  from  biodegradation  in  water  and  sediment  (simulation  tests)  are  described 
below. 

from 

The  aerobic  aquatic  degradation  of  [14C]-cyanamide  was  studied  in  two  disparate 
water/sediment systems: a pond and a river system. Results showed that the elimination 
of  [14C]-cyanamide 
the  water/sediment  systems  proceeded  mainly  via 
mineralisation to CO2. Degradation of cyanamide to other metabolites and incorporation 
into the organic matter of the sediment were of minor importance. The estimated half-life 
(DT50) of cyanamide from the water phase of the aquatic systems was 2.3 d for the river 
system  and  4.3  d  for  the  pond  system,  respectively,  and  the  DT90-values  were 
determined  to  be  7.7  d  and  14.4  d,  respectively.  In  the  total  water  sediment  systems, 
cyanamide  degraded  with  half-lives  of  2.5  d  (river)  and  4.8  d  (pond).  The  DT90  values 
for  the  total  systems  were  calculated  to  be  8.2  d  in  the  river  system  and  15.8  d  in  the 
pond system (AlzChem Trostberg, 2010). 

One major metabolite was detected in the pond system (13.4% of applied radioactivity) 
and  identified  as  urea.  The  DT50-  and  DT90-values  of  urea  were  also  calculated  using 
first-order  kinetics.  The  DT50  values  in  the  water  phase  were  calculated  to  be  2.7  and 
7.5 d for the river and pond systems, respectively, and the DT90-values were determined 
to  be  9.1  d  and  11.6  d,  respectively.  In  the  total  water  sediment  systems,  urea  was 
degraded with half-lives of 2.9 d (river) and 8.0 d (pond). The DT90-values for the total 
systems were calculated to be 9.6 d in the river system and 26.7 d in the pond system 
(Völkl, 2000). 

Biodegradation in soil 

According to the OECD 301B test (technical grade), CaCN2 cannot be classified as readily 
biodegradable  (no  degradation  was  observed  after  28d  of  incubation  between  21.0  and 
23.1 °C) because of insufficient CO2 evolution and therefore the biodegradability criterion 
was not fulfilled (Ipser, 2010a). 

As  shown  in  the  hydrolysis  study,  calcium  cyanamide  in  contact  with  water  rapidly 
hydrolyses to hydrogen cyanamide. In addition it should be noted that the use of calcium 
cyanamide as fertiliser is generally confined to soils which – at the time of application – 
exhibited aerobic conditions. Therefore the aerobic soil metabolism of calcium cyanamide 
is best characterised by using its hydrolysis metabolite cyanamide. 

The aerobic soil metabolism of [14C]-cyanamide (Schmidt, 1990/91) was investigated in 
air-dried sandy loam soil, collected from land located near Ashland, Nebraska, USA. The 
rate of degradation of cyanamide in soil was determined using linear regression assuming 
first-order reaction kinetics. The primary aerobic pathway by which the parent compound 
disappears  from  soil  was  the  final  degradation  to  [14C]-CO2  (complete  mineralisation). 
This  fraction  accounted  for  approximately  94.6%  of  applied  radioactivity  after  14  days. 
The  half-life  of  cyanamide  was  calculated  (using  a  first  order  kinetic)  to  be  1.26  d.  The 
calculated  time  to  90  %  degradation  was  1.94  d.  One  minor  degradation  product  was 
identified as dicyandiamide accounting for 0.43% of applied radioactivity at maximum. 

On  the  basis  of  the  cyanamide  concentrations  in  soil  at  various  time  points  after 
application, regression curves were fitted and the DT50-values were calculated from the 
regression  curves  using  a  graphical  estimation  method.  The  DT50-values  of  the  two 

21 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

loamy sand  soils  ranged  from  1  to  3  d.  These  results were  in  good  agreement  with  the 
values obtained in the aerobic soil metabolism study and during the aerobic phase of the 
anaerobic  soil  metabolism  study  where  the  DT50-values  ranged  from  0.52  to  1.26  d. 
Only in sandy soil with very low organic carbon content did the DT50-values range from 
6 to 12 d. 

An  anaerobic  degradation  DT50  value  in  soil  under  laboratory  conditions  was  calculated 
to be 34.7 d (AlzChem, 2015). 

The results showed that the degradation of cyanamide in soil is influenced by the organic 
carbon  content,  indicating  that  biotic  degradation  prevails  in  soils.  Furthermore,  the 
degradation  rate of  cyanamide  in  the  test  soils  depended on  the  application  rate  with a 
faster degradation observed in the test soils receiving the lowest application rate (Rieder 
and Heß, 1978). 

In another soil study, it was suggested that cyanamide was rapidly degraded in 2 weeks, 
but nitrification was depressed for a long period (Ohyama, et al., 2010). 

Cyanamide degradation in soil is influenced by the organic carbon content of soils. DT50 
values up to 12 d were found in sandy soil with a very low organic C content. 

The  SCHER  concluded  that  calcium  cyanamide  is  rapidly  degraded  into  hydrogen 
cyanamide and further into urea and/or completely converted to CO2 in the sediment and 
soil with DT50 value of a maximum of 12 d and a mean value of a few d in soil and 1.4 d 
in water. 

The SCHER chose a DT50 of 2 d in soil and 1.4 d in water as typical values for calcium 
cyanamide  degradation based on the above information. These values were used in the 
calculations presented below. 

Bioaccumulation and sorption 

From its physical-chemical characteristics (see 3.2.2), calcium cyanamide is expected to 
have a low potential for bioaccumulation and for adsorption to soil. 

The adsorption coefficient, Koc, of CaCN2 has been estimated using a HPLC retention time 
method.  At  any  pH,  the  compound  dissociates  in  water  because  it  is  a  salt.  The 
adsorption  coefficient  of  the  non-ionised  form  could  not  be  determined.  HPLC  based 
values of log Koc were estimated to be < 1.25 (which was outside the method’s scope). 
Calculated values range between 0.9 and 1.2 (EpiSuite, see Annex 1). 

Bioaccumulation  is  generally  considered  to  be  related  to  the  octanol  –  water  partition 
coefficient. With a log Pow of - 0.20 the substance was classified as not bioaccumulative 
as  bioaccumulation  is  considered  a  relevant  process  at  a  Log  Pow  value  of  >  3.  For 
sorption, if it is assumed that the log Koc is 1.25, the Koc itself can be estimated at 17.8 
dm3/kg  and  the  Kom  at  10.5  dm3/kg,  which  is  indicative  of  a  low  adsorption  capacity  to 
soil.  According 
follow-up  process  of 
bioconcentration, was not considered a relevant process for calcium cyanamide. 

the  SCHER,  biomagnification,  as  a 

to 

For its calculations the SCHER selected a Kom value of 10.5 dm3/kg. 

22 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

3.2.6.  Ecotoxicological assessment 

3.2.6.1.  Aquatic ecotoxicity 

Most  aquatic  ecotoxicity  data  used  by  the  SCHER  originated  from  the  manufacturer’s 
dossier  (AlzChem  Trostberg,  2010);  these  are  the  same  as  those  in  the  CSR  (AlzChem 
Trostberg,  2015).  The  studies  were  generally  carried  out  according  to  internationally 
accepted guidelines and using GLP. 

A brief description of the main studies is given hereunder. 

In  a  96-h  acute  toxicity  study,  zebra  fish  (Danio  rerio)  were  exposed  to  calcium 
cyanamide  (technical  grade)  at  nominal  concentrations  ranging  from  25.0 to  401  mg/L. 
All fish exposed to 401 mg/L died within the first 2 hours of testing. Organisms exposed 
to  200  mg/L  exhibited  decreased  mobility  after  2  hours  and,  after  24  hours  mortality 
started  to  occur.  After  48  hours  of  exposure  the  remaining  fish  showed  loss  of 
equilibrium  and  bleeding  around  the  mouth  and  the  chest,  and  3  of  these  fish  were 
recorded as having died. The remaining fish in this group were dead 24 hours later. None 
of the fish in the other test groups or in the control group exhibited any adverse effects 
throughout  the  study.  The  calculated  96h-LC50  of  calcium  cyanamide  (technical  grade, 
Kalkstickstoff)  in  this  study  was  140  mg/L  (based  on  nominal  concentrations).  The 
derived (96h) NOEC was 100 mg/L (AlzChem Trostberg, 2010).  

For  several  aquatic  organisms,  e.g.  invertebrates  and  algae,  the  toxicity  of  urea  is  less 
(by a factor 100 or more) than that of calcium cyanamide. For fish, however, the toxicity 
of  urea  and  calcium  cyanamide  are  in  the  same  range  (i.e.  128  mg/L  for urea  and  140 
mg/L for calcium cyanamide). 

In  a  48-h  toxicity  study  with  Daphnia  magna  (Crustacea,  Cladocera),  neonates  were 
exposed  to  CaCN2  at  nominal  concentrations  ranging  from  1.32  to  42.8  mg/L  calcium 
cyanamide. The calculated 48h-EC50 (immobility as endpoint) was 6 mg CaCN2/L and the 
derived 48h-NOEC (based on immobilization) was 1.8 mg/L (AlzChem Trostberg, 2010). 

In  a  72-h  growth  inhibition  test  study,  the  unicellular  algae  Pseudokirchneriella 
subcapitata  was  exposed  to  calcium  cyanamide  (technical  grade)  at  nominal 
concentrations  ranging  from  0.74  to  200  mg/L.  The  NOEC  and  EC50  values  based  on 
growth rate were 13.7 and 27.5 mg/L, respectively (AlzChem Trostberg, 2010). 

Other  algae  toxicity  data  (with  exposure  periods  up  to  8  days)  available  from  a  public 
available  literature  source  (IUCLID4  from  ECB  website)  were  also  considered  by  the 
SCHER, but were not retained as critical ecotoxicity values.  

From all ecotoxicity data available, the SCHER chose the L(E)C50 data presented in Table 
3 as the critical values to be used in the risk assessment for calcium cyanamide. 

Table 3. Ecotoxicity values used for the risk assessment of calcium cyanamide performed 
in this Opinion. 

Organism 

Fish 
Crustaceans 
Algae 

calcium cyanamide 
140 
6 
28 

Short term (L(E)C50) 
(mg/L) 
cyanamide 
43.1 
3.2 
0.65 

urea 
128 
10,000 
10,000 

23 

 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

The SCHER notes that no chronic toxicity data are available. The SCHER is, however, of 
the  opinion  that  chronic  exposure  and  toxicity  cannot  be  excluded  as  the  formulation 
releases the active substance slowly and it can therefore be present in the environment 
for considerable periods during the growing season. In the CSR it is argued that chronic 
data  are  not  needed  as  the  substance  degrades  rapidly.  This  is  contradictory  to  recent 
regulatory  developments.  Indeed,  it  should  be  noted  that  the  European  Chemicals 
Agency’s  RAC  recently  classified  cyanamide  as  harmful  to  aquatic  life  with  long  lasting 
effects (RAC, 2015), thus implying that chronic effects can be expected. 

3.2.6.2.  Terrestrial ecotoxicity 

Birds 

The  acute  oral  toxicity  of  PERLKA  to  Japanese  quail  (Coturnix  coturnix  japonica)  was 
assessed during a single dose 14-day assay. Clinical observations during the first 4 post-
treatment hours revealed sluggishness and slight diarrhoea. Most of the deaths occurred 
between 3 and 20 h after treatment. One cock died on the fifth day post-treatment. The 
survivors subsequently recovered gradually and looked quite healthy again at the end of 
the observation period. The individual body weights indicated retarded growth or weight 
loss  in  the  first  week  post-treatment.  Macroscopic  examination  of  the  survivors  at 
autopsy  did  not  reveal  any  treatment-related  gross  alteration.  From  the  mortality  data 
the calculated oral LD50 of PERLKA was 1,665 mg/kg bw/d with 1,575 and 1,763 as the 
95% confidence limits (AlzChem Trostberg, 2010). 

No  other  toxicity  studies  with  birds  were  available  in  the  information  presented  to  the 
SCHER. Although the SCHER recognises the limited number of terrestrial toxicity studies 
available,  the  committee  is  of  the  opinion  that  due  to  the  rather  high  LD50-values 
determined  and  the  feed  avoidance  behaviour,  additional  toxicity  studies  (including 
chronic) for birds are not required (especially if during application the granulated product 
was incorporated into the soil). 

Earthworms 

The  acute  toxicity  of  calcium  cyanamide  (using  PERLKA)  to  the  earthworms  Eisenia 
foetida  and  Lumbricus  terrestris  was  determined  in  14-day  toxicity  tests  conducted 
according  to  OECD  Guideline  207.  Worms  were  assessed  for  mortality  and  sublethal 
effects  after  7  and  14  days  of  exposure.  The  14d-LC50  of  calcium  cyanamide  was  169 
mg/kg  dry  soil  for  Eisenia  foetida  and  182  mg/kg  dry  soil  for  Lumbricus  terrestris 
(AlzChem Trostberg, 2010). 

Another  acute  toxicity  with  PERLKA  and  earthworms  (E.  fetida),  i.e.  also  a  14-day  soil 
exposure laboratory study conducted according to OECD Guideline 207, reported a 14d-
LC50 of AlzChem173 mg/kg soil dw for calcium cyanamide. (AlzChem Trostberg, 2010) 

Based  on  the  latter  LC50-value  the  SCHER  derived  a  PNEC  for  soil  organisms  of  17.3 
mg/kg dw using an AF of 10. 

Beetles 

A  laboratory  study  was  carried  out  to  determine  the  toxicity  of  PERLKA  to  the  carabid 
beetle  Bembidion  lampros.  No  toxicity  was  observed  up  to  a  concentration  of  450  kg 
formulation/ha, i.e. the highest concentration tested (AlzChem Trostberg, 2010). 

The  SCHER  notes  that  toxicity  tests  with  concentrations  reflecting  application  rates  of 
PERLKA (in several crops) of 500 to 1000 kg formulation/ha are not available. 

24 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Microorganisms 

To determine effects to microorganisms, a nitrification and dehydrogenase activity study 
has been carried out with dosages of 1,000 and 5,000 kg formulation/ha. At a dosage of 
1,000  kg  formulation/ha,  i.e.  the  highest  application  concentration  considered  in  this 
opinion,  no  effects  on  nitrification  and  dehydrogenase  activity  were  observed  (AlzChem 
Trostberg, 2010). The SCHER concluded that the fertiliser PERLKA exhibits a low toxicity 
to microorganisms. 

Plants 

Calcium  cyanamide  did  not  exhibit  toxicity  to  higher  plants.  It  was  reported  to  have 
positive  effects  on  plant  growth  (AlzChem  Trostberg,  2010).  Hydrolysis  product(s)  of 
calcium  cyanamide,  however,  were  reported  to  exhibit  some  toxicity  to  seeds  and 
seedlings. 

Bees 

Toxicity data of calcium cyanamide to bees were not available to the SCHER. Therefore, 
the SCHER was not able to perform a risk assessment for bees. However, the SCHER is of 
the opinion that bees will not be exposed during the time of application. 

3.2.7.  Mammalian toxicology 

Kinetics (Absorption, distribution, metabolism, excretion) 

Although  calcium  cyanamide  had  been  clinically  available  for  decades,  only  a  few 
scientific studies, if any, on pharmacokinetics were available in the literature. It had been 
demonstrated  that  calcium  cyanamide  was  quantitatively  hydrolysed  to  cyanamide  at 
different  pH  and  also  under  simulated  gastric  conditions  within  minutes  or  in  1h  (Rust, 
1987;  Brien  and  Loomis,  1983;  Mertschenk,  et  al.,  1991).  Calcium  cyanamide  in  tablet 
formulation,  however,  hydrolysed  to  cyanamide  to  an  extent  of  60%  within  1  hour  and 
quantitatively  within  10  hours  (Brien  and  Loomis,  1983).  Hydrolysis  of  calcium 
cyanamide was reported to be required for drug absorption and it could be assumed that 
calcium cyanamide follows mainly the same kinetic pathways as cyanamide. 

In rats, absorption of cyanamide after oral application was calculated to be approximately 
90% with slightly higher values for fasted animals (EFSA, 2010a; Obach, 1986). Also in 
humans,  absorption  was  fast  after  oral  administration  of  therapeutic  doses  of  0.3  (low 
dose), 1 (medium dose), and 1.5 (high dose) mg/kg bw/d and highest blood levels (Tmax) 
were  reached  after  13  minutes.  The  substance  was  widely  distributed  and  the  highest 
amounts  were  observed  in  liver  and  kidney,  however,  there  was  no  evidence  for 
bioaccumulation. In humans, bioavailability increased from 46% after oral administration 
of  low  doses  to  70%  or  81%  for  the  medium  and  high  doses,  respectively,  indicating  a 
saturable  first  pass  metabolism  (Colom,  1999).  Elimination  was  rapid  in  rats  (>67% 
within  first  24  hours  post  dose)  as  well  as  in  humans.  Plasma  half-life  (T1/2)  of 
cyanamide  was  reported  to  be  of  about  one  hour  in  rats  after  oral  administration  of  35 
mg/kg  bw  and  40  to  60  minutes  in  humans  after  oral  administration  of  the  different 
therapeutic  doses.  Excretion  in  rats  occurs  mainly  via  urine  (80  –  98%),  while  2  –  4% 
was excreted via faeces and 4 – 10% via respiratory air. Biliary excretion was increased 
following  intravenous  administration.  43  –  55%  (rats)  or  28  –  58%  (humans)  of  the 
substance  applied  were  excreted as  N-acetylcyanamide,  which  was  the  main  metabolite 
in  rats,  dogs,  rabbits  and  humans  (Shirota,  1984;  Obach,  1986;  Obach,  1989; 
Gloxhuber, 1989; Mertschenk, et al., 1991; Colom, 1999). 

25 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Mechanistic  studies  regarding  the  inhibition  of  aldehyde  dehydrogenases  showed  that 
cyanamide  itself  was  not  active  in  vitro  and  has  to  be  activated  by  the  mitochondrial 
catalase  enzyme.  This  resulted  in  the  formation  of  an  unstable  N-hydroxycyanamide 
intermediate  that  decomposed  to  cyanide  (CN)  and  nitroxyl  (HNO).  While  cyanide  and 
thiocyanate  had  not  been  found  in  significant  amounts  in  human  blood  and  urine, 
respectively,  nitroxyl  had  been  identified  as  the  active  metabolite  responsible  for  the 
inhibition  of  aldehyde  dehydrogenases  and  active  levels  where  reached  at  therapeutical 
doses of 0.3 mg/kg bw/d (DeMaster, et al., 1998). 

Mechanisms  of  cyanamide  toxicity  were  not  fully  understood  but  the  inhibition  of 
aldehyde dehydrogenases could also play a role with regard to undesired side-effects of 
the drug. Additionally, activation of the hypothalamo-pituitary-adrenal axis by cyanamide 
resulting  in  an  increase  of  circulating  glucocorticoids  seemed  to  be  correlated  to 
cyanamide toxicity and its effects on thyroid and testis function in rats and dogs, as well 
as in the reduction of fertility in rats. 

Dermal absorption 

Information  on  dermal  absorption  was  based  on  data  for  cyanamide.  Calculated  on  the 
urinary  excretion  of  the  main  metabolite  N-acetylcyanamide  after  oral  and  dermal 
exposure  in  humans,  maximum  dermal  absorption  from  a  1%  aqueous  cyanamide 
solution following a 6 h exposure period was reported to be 3.5% (Gloxhuber, 1989). In 
rats, dermal absorption amounted to 14.3% for a 10% and to 8.2% for a 0.1% solution 
after  10  h  exposure.  For  cyanamide  EFSA  concluded  on  a  dermal  absorption  of  5%  for 
1%  dilution,  a  dermal  absorption  of  14.3%  for  2.5%  dilution  and  100%  dermal 
absorption for the cyanamide concentrate (EFSA, 2010a). 

In  a  dermal  absorption  with  6  human  volunteers,  10  mg  cyanamide  (0.1%  aqueous 
solution) was applied topically over a 6-hour period to the skin, about 7.7% was found as 
acetylcyanamide in the urine 48 hours after application (Mertschenk, 1991). 

The  German  Permanent  Senate  Commission  for  the  Investigation  of  Health  Hazards  of 
Chemical  Compounds  in  the  Work  Area  (MAK  Commission)  concluded  that  skin 
penetration contributes considerably to internal, systemic exposure and compliance with 
the  relevant  occupational  exposure  limit  did  not  guarantee  sufficient  protection  (MAK 
Commission, 1979, 1997). 

Acute Toxicity 

In rats for calcium cyanamide (purity 68%) an LD50 of 765 mg/kg bw has been reported, 
while the LD50 for the pure substance or the tablet formulation was 690 mg/kg bw and 
for the commercial formulation (with a calcium cyanamide content of 45%) the LD50 was 
711  mg/kg bw  for males  and  492  mg/kg  bw for females,  respectively  (de Groot,  1976; 
Berger, 1966; Osheroff, 1990). In mice the LD50 for calcium cyanamide, (purity 63.5%) 
was 1800 mg/kg bw (Allan, 1992). 

In a study with the commercial formulation, an acute inhalation LD50 of >5.1 mg/L was 
derived  (Terrill,  1990).  In  further  studies  acute  LD50  was  above  the  concentrations 
tested (155 mg/m3 non-oiled or 132 mg/m3 oiled calcium cyanamide) (Appelman, 1978, 
1979). 

The  acute median  lethal  dermal  dosage  was  established  at  >2000 mg/kg  bw  (Osheroff, 
1990; Liggett, 1989). 

Irritation, Corrosion 

26 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Calcium cyanamide was not irritating or corrosive to the skin when tested in vitro (Ipser, 
2010) or in vivo (Liggett, 1989). Dermal exposure to 2000 mg/kg bw, however, induced 
erythema and necrosis (Osheroff, 1990, Liggett, 1989). 

Calcium cyanamide induced severe eye damage in vitro (Ipser, 2010) as well as in vivo 
(technical grade: Liggett, 1989, commercial formulation: Mercier, 1989). 

Sensitisation 

Calcium cyanamide (technical grade) was positive in a modified guinea pig maximisation 
test (GPMT, OECD test guideline 406). The test was modified due to the poor solubility of 
the  test  substance  in  solvents.  Occupational  studies  in  65  workers  showed  no  evidence 
that  calcium  cyanamide  was  a  human  skin  sensitiser  or  a  respiratory  sensitiser  (MAK 
Commission,  1997).  In  an  occupational  health  examination,  calcium  cyanamide  was 
negative in a Finn-Chamber test (Mertschenk, et al., 1991). 

Repeated dose toxicity 

Target  organs  for  systemic  effects  of  calcium  cyanamide  observed  in  experimental 
animals were liver, thyroid gland, pituitary gland and the reproductive system (Benitz, et 
al., 1965; Benitz and Cavallo, 1960). The morphological activation of the thyroid was to 
be  expected,  as  calcium  cyanamide  was  known  as  an  anti-thyroid  agent  and 
administration  of  calcium  cyanamide  in  combination  with  thyroid  powder  minimised  the 
effect of calcium cyanamide on bodyweight gain (Pridgen, 1966). 

In  a  4-week  dose  range  finding  study  with  rats  the  NOAEL  was  reported  for  the  group 
which received daily doses of 8.3 – 12.6 mg/kg bw/d (Benitz and Tonelli, 1957). 

In  a  chronic  study,  rats  were  fed  for  17  –  50  weeks  with  dosages  of  0.003%,  0.012%, 
0.05% and 0.2% calcium cyanamide in the diet (Benitz and Salamandra, 1960; Cavallo, 
1960).  Because  of  the  high  mortality  rate,  treatment  was  reduced  to  7  months  for 
surviving  animals  of  the  highest  dosage  level.  In  the  0.05%  and  in  the  0.012%  dosage 
groups  two  animals  and  one  animal  died,  respectively.  At  0.012%,  morphological 
activation of the thyroid and thyroidectomy cells in the pituitary were observed. Also for 
the  0.003%  dosage  group,  cases  of  moderate  morphological  activation  of  the  thyroid 
were  reported.  As  the  thyroid  was  one  of  the  main  target  organs  affected  by  calcium 
cyanamide,  any  effects  on  this  organ  have  to  be  considered  as  long  as  a  possible 
relationship  to  calcium  cyanamide  administration  cannot  be  excluded.  In  the  study,  no 
data  on  clinical  chemistry  were  provided.  The  haematological  values  of  rats  receiving 
0.05%  calcium  cyanamide  in  their  feed  for  1  year  were  reported.  Mean  values  do  not 
seem  to  be  remarkably  different  from  those  of  control  rats,  however  no  statistical 
analysis  of  the  data  was  given.  Based  on  the  information  available  from  this  study,  the 
SCHER  derived  a  LOAEL  of  0.003%  corresponding  to  a  daily  intake  of  1.3  –  3.8  mg/kg 
bw/d. 

The  0.012%  dose  level  (about  11  mg/kg/d)  did  not  cause  any  morphological  changes 
attributable  to  treatment  with  the  exception  of  a  few  cases  of  thyroid  hyperplasia  with 
the occurrence of thyroidectomy cells and the decrease of acidophilic cells in the anterior 
pituitary.  The  thyroid  hyperplasia  was  in  rare  instances  noticeable  in  animals  receiving 
the 0.003% diet. 

A  6-month  oral  toxicity  study  was  performed  in  dogs  with  calcium  cyanamide 
(pharmaceutical  grade)  (Benitz  and  Takesue, 1960).  Two  animals  per  group  (one  male, 
one  female)  were  treated  at  2,  10  or  30  mg/kg  bw/d.  Since  the  two  animals  of  the 
highest dosage group died on days 9 and 13, respectively, these animals were replaced 

27 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

and  an  additional  group  of  two  dogs  was  added  which  received  7.5  mg/kg  bw/d  of 
calcium  cyanamide.  Treatment  at  the  highest  dosage  of  30  mg/kg  bw/d  caused  severe 
toxic symptoms like ulcers in the upper gastrointestinal tract, fatal lung edema, increased 
weight of the thyroid and leukopenia. A considerable increase in lung weight was already 
noted in the two animals of the highest dosage group which were found dead 9 and 13 
days  after  start  of  treatment,  respectively.  In  addition,  the  male  animal  showed 
increased  weight  of  the  testes.  Dogs  receiving  10  mg/kg  bw/d  showed  a  decrease  in 
bodyweight  of  6%  in  the  male  and  14%  in  the  female  animal.  Significant  changes  in 
some  organ  weights  were  noted  for  all  treated  animals  and  include  reduced  absolute 
thymus weight in males (10, 7.5 and 2 mg/kg bw/d), increased relative spleen weight in 
males (10, 7.5 mg/kg bw/d), decreased in relative heart weight in males (10, 7.5 and 2 
mg/kg bw/d), reduced relative pancreas weight in males (10, 7.5 mg/kg bw/d), slightly 
increased  absolute  and  relative  thyroid  weights  in  males  (10,  7.5  mg/kg  bw/d), 
considerably  decreased  absolute  and  relative  liver  weights  in  females  (10,  7.5  and  2 
mg/kg bw/d), reduced absolute pituitary gland weight in females (10, 7.5 and 2 mg/kg 
bw/d),  as  well  as  considerably  decreases  in  relative  and  absolute  ovaries  and  uterus 
weights  (10,  7.5  and  2  mg/kg  bw/d).  However,  weight  of  the  sexual  organs  in  females 
might not be completely comparable, as the control female animal was reported to be “in 
heat” from one to one and a half weeks. A decrease of the total white blood count during 
the study was noted in all groups but in the highest dose group at an earlier stage than 
in control animals and in other treatment groups. This observation could not be explained 
by  the  authors  and  findings  cannot  be  evaluated  with  regard  to  drug  effects.  Atypical 
leucocytes  with  band-like  nuclei  and  very  bizarre  and  irregular  shapes,  however,  were 
reported for dosage groups of 7.5 mg/kg bw/d and higher but not for controls and might 
indicate an effect of calcium cyanamide on white blood cells. 

In  the  opinion  of  the  SCHER,  the  reliability  of  this  study  was  limited  because  bone 
marrow seems to be a human-relevant target for calcium cyanamide toxicity but for this 
study definite interpretation for occurrence of leucopoenia in all groups was not feasible. 
Based  on  effects  on  body  weight  as  well  as  on  organ  weights  (thymus  in  males  and 
ovaries  and  uteri  in  females)  the  SCHER  concluded  that  the  LOAEL  from  this  study  is  2 
mg/kg bw/d. 

Genotoxicity 

Calcium cyanamide was evaluated for its mutagenic and genotoxic potential. Ames tests 
were negative both in the absence and in the presence of metabolic activation (Willems, 
1978;  Haworth,  et  al.,  1983).  A  non-guideline  bacterial  mutation  test  with  calcium 
cyanamide in Aspergillus nidulans was positive in the absence of S9-mix, but negative in 
its  presence  (Vallini  et  al.,  1983).  Both  a  mammalian  chromosomal  aberration  test  as 
well  as  an  UDS  test  in  a  human  cell  line  on  calcium  cyanamide  were  shown  to  be 
negative (De Raat, 1979; Lohman, 1981). In an in vivo micronucleus test, no mutagenic 
activity of calcium cyanamide was observed (Willems, 1979). 

Carcinogenicity 

In  chronic  studies  with  rats  and  mice,  no  tumours  occurred  at  incidences  that  could 
clearly  be  related  to  the  administration  of  calcium  cyanamide.  In  male  mice, 
hemangiosarcomas were increased as well as lymphomas and leukaemia in female mice, 
however, the incidences of these tumours were reported to be in the range of values for 
historical  controls.  In  subchronic  studies  performed  with  rats,  calcium  cyanamide  was 
found to cause diffuse follicular hyperplasia of the thyroid, with periglandular fibrosis and 
prominent periglandular vascularity (NCI, 1979). 

28 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

In  an  additional  study,  the  probability  of  calcium  cyanamide  leading  to  reticulum  cell 
carcinoma was reported to be very low after oral application of 100 mg /kg bw/d for 18 
month to mice (Kotin, 1968). 

Developmental and Reproductive toxicity 

A  study  on  developmental  toxicity  (Wil  research,  2014)  was  performed  in  Sprague-
Dawley  rats  that  received  0,  7,  21  or  49  mg/kg  bw/d  (nominal  conc.)  of  calcium 
cyanamide  in  corn  oil  daily  by  gavage  between  G6  and  G19.  Dose  related  reductions  in 
body  weight  and  food  consumption  were  observed  in  the  mothers  from  21  mg/kg  bw/d 
on. The NOAEL was set at 7 mg/kg bw/d for maternal toxicity. At these dose levels (21 
and 49 mg/kg bw/d) both the uterus weight and foetal weight were also slightly reduced. 
The SCHER selected 7 mg/kg bw/d as the NOAEL for developmental toxicity. There were 
1 and 2 malformed foetuses in the control and lowest dose group respectively that were 
not considered as being associated with the treatment. No other effects on the offspring 
were even observed. The NOAEL for teratogenicity can be set at > 49 mg/kg bw /d. The 
following  litter  parameters  were  recorded:  number  of  foetuses  (dead/alive),  uterus 
weight, foetal weight, macroscopic effects and external abnormalities. 

Neither a two-generation reproduction study (OECD 416) or an extended one-generation 
study in rats is currently available. 

The  German  Permanent  Senate  Commission  for  the  Investigation  of  Health  Hazards  of 
Chemical  Compounds  in  the  Work  Area  evaluated  the  reproductive  toxicity  of  calcium 
cyanamide  on  the  base  of  data  for  cyanamide  and  classified  calcium  cyanamide  as 
embryotoxic  substance,  for  which  effects  on  reproduction  were  not  suspected  if  specific 
exposure  limits  for  workplace  were  not  exceeded  (MAK-Commission,  2007,  2012).  For 
cyanamide EFSA concluded that the relevant maternal and developmental NOAELs were 
<5  mg/kg  bw/d  and  5  mg/kg  bw/d  in  rats,  respectively,  as  well  as  6  mg/kg  bw/d  in 
rabbits. For parental and reproductive toxicity, the NOAEL was 3.75 mg/kg bw/d, based 
on  the  reduced  body  weight  gain  and  fertility  impairment.  For  offspring  toxicity,  the 
NOAEL was <1.25 mg/kg bw/d, based on neonate mortality. Cyanamide was considered 
as  having  an  effect  on  testis  development  of  the  F1  males  during  the  late  lactation 
period, leading to interstitial cell proliferation and tubular atrophy. Fertility reduction was 
seen at a dose of 15 mg/kg bw/d, inducing general toxicity. The NOAEL for teratogenicity 
was 45 mg/kg bw/d (EFSA, 2010a). 

Human experience 

Many  studies  reported  on  the  so-called  nitrolime-disease,  the  effects  of  calcium 
cyanamide after the consumption of alcohol. The dose for long-term therapy was 50 mg 
calcium  cyanamide  every  12  hours.  Daily  ingestion  of  50  mg  calcium  cyanamide  for  20 
days in a double blind study led to frequent abdominal symptoms, allergic skin reactions, 
dizziness, nausea, sleepiness, headache and eye symptoms (MAK Commission, 1979). 

Also for healthcare workers, generalised symptoms of acute toxicity were reported. After 
occupational skin contact with calcium cyanamide, severe erythema, inflammation, ulcers 
and lesions on the skin and mucous membranes were reported (MAK Commission, 1979). 
Six  percent  of  workers  exposed  to  >2.5  mg  calcium  cyanamide/m3  developed 
conjunctivitis  (Schiele,  et  al.,  1981).  A  case  study  with  65  employees  revealed  no 
evidence of exposure-related adverse effects on health. The workplace concentrations of 
calcium cyanamide were in the range between 0.23 and 8.36 mg/m3. Employees from a 
calcium cyanamide production plant were investigated for hormonal changes. No changes 
in  blood  levels  were  detected  in  the  group  of  exposed  compared  to  unexposed  workers 
29 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

(Mertschenk,  1993).  Extent  of  exposure  to  calcium  cyanamide,  however,  varied 
considerably within the group of workers and no individual data for the hormone levels in 
blood was provided so possible trends in hormonal variations for highly exposed persons 
cannot  be  identified.  The  MAK  Commission  recommended  a  health-based  occupational 
exposure level of 1 mg/m3 for calcium cyanamide derived from therapeutic doses and set 
the occupational exposure limit (OEL) at 10% of a daily dose of 100 mg/person which is 
equal  to  1  mg/m³  assuming  a  total  inhaled  air  volume  of  10  m³  per  shift  (MAK 
Commission, 1979).  

Classification of cyanamide  

With  regard  to  health  hazards,  the  RAC  concluded  on  the  following  Hazard  Statements 
and Hazard Class Categories for cyanamide (RAC, 2015): 

H 301: 

H 311: 

H 314: 

H 317: 

H 351: 

Toxic if swallowed (Acute Tox. 3) 

Toxic in contact with skin (Acute Tox. 3) 

Causes severe skin burns and eye damage ((Skin Corr. 1) 

May cause an allergic skin reaction (Skin Sens. 1) 

Suspected of causing cancer (Carc. 2) 

H 361 fd:   

Suspected of damaging fertility or the unborn child (Repr. 2) 

H 373 (thyroid):  May  cause  damage  to  organs  through  prolonged  or  repeated 

exposure (STOT RE 2) 

The  RAC  supported  the  classification  as  STOT  RE  2,  based  on  thyroid  effects  in  the  rat 
and  supported  by  some  findings  in  dog  studies.  This  conclusion  takes  into  account  the 
particular  sensitivity  of  rats  as  well  as  evidence  of  probable  higher  sensitivity  of  dogs 
compared to humans. 

Overall conclusion on toxicity 

Based on kinetic data available, the SCHER concludes that calcium cyanamide hydrolysed 
to cyanamide after oral administration to experimental animals as well as to humans and 
that toxic effects observed for calcium cyanamide were mainly attributable to cyanamide 
toxicity.  Kinetic  parameters  showed  that  relevant  cyanamide  blood  levels  were  reached 
later  and  cyanamide  elimination  was  slower  after  calcium  cyanamide  exposure  rather 
than  after  exposure  to  cyanamide  itself.  Delay  in  systemic  bioavailability  of  cyanamide 
after oral administration of calcium cyanamide would also explain lower acute toxicity of 
calcium cyanamide: Oral LD50 values for calcium cyanamide were in the range of 400 to 
1,800  mg/kg  bw  while  for  cyanamide  the  oral  LD50  was  142  to  223  mg/kg  bw  (EFSA, 
2010a). However, after subchronic and chronic exposure, values for NOAEL seemed to be 
in the same range for both substances. 

For  cyanamide,  the  main  target  organs  following  repeated  oral  administration  were  the 
thyroid  (rat,  dog)  and  the  testes  (dog)  as  well  as  red  blood  cells  (rat,  dog).  Testicular 
lesions have been reported in young immature beagle dogs at 0.6 mg/kg bw/d in a 90-
day  study.  EFSA  used  this  study  to  derive  a  LOAEL  of  0.6  mg/kg  bw/d  for  regulatory 
purposes. For adult dogs, a NOAEL of 1 mg/kg bw/d was derived as well as a NOAEL of 
1.5 mg/kg bw/d for rats. The RAC supported a LOAEL of 4.5 mg/kg bw/d in rats based on 
significant effects on the thyroid observed in males and females of two strains. In the 90-
day and  1-year dog studies,  hypothyroidism was  reported  at  doses of  2-6  mg/kg  bw/d. 

30 

 
 
 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

These findings were considered to have toxicological significance and to be of relevance 
to human health (RAC, 2015). 

For  calcium  cyanamide,  effects  were  comparable  after  repeated  exposure  with  the 
thyroid  and  the  reproductive  system  reported  to  be  main  target  organs  affected.  From 
the information available from a rat study (Benitz and Salamandra, 1960, Cavallo 1960), 
the SCHER derived a LOAEL of 0.003%, corresponding to a daily intake of 1.3-3.8 mg/kg 
bw/d.  From  the  6-month  study  with  dogs  a  LOAEL  of  2  mg/kg  bw/d  could  be  derived, 
however,  this  study  was  considered  to  be  of  limited  reliability.  A  recent  developmental 
study  in  rats  showed  reduced  maternal  weight  gain  and  food  consumption  as  well  as 
reduced foetal weight but no excess foetal mortality. The SCHER selected a NOAEL of 7 
mg/kg  bw/day  for  developmental  toxicity  and  a  NOAEL  of  49  mg/kg  bw  /d  for 
teratogenicity,  since  no  such  effects  were  observed  at  the  dose  levels  that  were  used. 
Calcium  cyanamide  did  not  seem  to  be  a  potent  human  skin  sensitiser  although  the 
substance  showed  sensitising  properties  in  experimental  animals.  In  contrast,  skin 
irritating properties of this substance seemed to be more pronounced in humans than in 
animals. 

To summarise, the SCHER uses for its assessment the LOAEL of 1.3 mg/kg bw/d together 
with following assessment factors to derive the AOEL of 0.0043 mg/kg bw/d: 

3 

4 

2.5 

10 

for the extrapolation from LOAEL to NOAEL 

for allometric scaling (rats to humans) 

for other interspecies differences 

for intraspecies differences 

3.2.8.  Operator, bystander and residential exposure estimates 

Exposure assessment for operators, professional use: 

The manufacturer provided measured inhalatory exposure data for operators. For mixing 
and loading of calcium cyanamide fertiliser, handling six bags of 600 kg net content for 
18  minutes  or  handling  12  bags  with  50  kg  net  content  for  12  minutes  resulted  in 
concentrations  of  0.21  or  0.13  mg/m3  air,  respectively.  Data  were  generated  by  a 
personal  air  sampling  system,  measured  as  cyanamide  and  recalculated  to  the 
corresponding calcium cyanamide concentrations. Additionally, a worker equipped with a 
personal  air  sampling  system  applied  350  kg  PERLKA/ha  on  a  field  of  5.1  ha  for  60 
minutes.  Calcium  cyanamide  concentrations  reported  for  this  application  were  0.06 
mg/m3  in  an  open  tractor  and  below  detection  limit  of  0.01  mg/m3  in  a  closed  cabin 
approach (AlzChem Trostberg, 2013, see also Table 3, manufacturer scenario). 

The SCHER uses these data in a first approach to assess operator inhalatory exposure to 
calcium cyanamide during mixing, loading and application. Therefore the measured data 
from the manufacturer scenario were used to calculate inhalatory exposure for different 
scenarios:  a  realistic  worst  case  with  an  application  rate  of  1,000  kg  formulation/ha  as 
well  as  a  normal  case  with  an  application  rate  of  500  kg  formulation/ha.  For  both 
scenarios the exposure was calculated considering different field sizes: a small field of 3 
ha, and a large field of 48 ha taking into account greater fields used e.g. for cabbage in 
certain  parts  of  the  EU.  The  SCHER  used  an  expected  concentration  in  the  air  of  0.21 
mg/m3  for  calculations  of  exposure  during  mixing  and  loading  as  well  as  an  expected 
concentration in the air of 0.06 mg/m3 for the calculation of exposure during application. 
The SCHER acknowledges, that the use of tractors with dust – tight cabins would reduce 

31 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

the  inhalative  exposure  for  workers  during  application  of  the  granules  to  the  field. 
However,  the  SCHER  has  no  information  on  use  and  availability  of  such  tractors  for 
farmers within all European member states. For small fields rotators with a working width 
of  12  m  were  considered  and  for  large  fields  rotators  with  a  working  width  of  24  m. 
Factors  were  applied  in  order  to  address  different  amounts  of  dust  from  the  different 
rotators.  

The SCHER’s estimation of inhalatory exposure for operators resulted in values exceeding 
the  AOEL  for  the  realistic  worst  case  and  the  normal  case  scenarios  (for  further  details 
see Table 4). It has to be kept in mind, that the realistic worst case (1000 kg/ha) and the 
normal  case  (500  kg/ha)  scenarios  were  based  on  data  measured  for  a  much  lower 
application  rate  (350  kg/ha).  Measured  values  can  also  not  be  used  for  the  exposure 
assessment of private users, bystanders and residents. 

Table 4: Exposure assessment for operators, inhalation only, approach based on data 
measured by the manufacturer. 
M: mixing, L: loading, Appl: application, AF: assessment factor. 

Besides inhalatory exposure, for mixing and loading but also for application of fertilisers, 
dermal  exposure  has  to  be  considered  appropriately.  For  granular  formulations  the 
dermal  exposure  is  considered  to  be  relevant.  A  second  approach  to  model  exposures 
was  therefore  performed  by  the  SCHER  taking  into  account  dermal  exposure  as  well.  A 
dermal  penetration  rate  of  10%  is  considered  appropriate  to  calculate  the  dermal 
exposure of calcium cyanamide when used as fertiliser. 

At  present  there  are  no  internationally  harmonised  and  accepted  exposure  models  for 
fertilisers available. The SCHER therefore used models developed in the UK1 for granule 
pesticide  formulations  which  were  considered  to  be  also  appropriate  for  fertilisers.  The 
model used for operators took into account data from a large number of field studies on 
dermal and inhalatory exposure. This model selected appropriate data from its database 

1 For further information see http://www.pesticides.gov.uk/guidance/industries/pesticides/topics/pesticide-
approvals/pesticides-registration/applicant-guide/the-applicant-guide-completing-an-application-overview-for-
operator-and-consumer-exposure 

32 

Abbr.Formulamanufacurersmall fieldlarge fieldsmall fieldlarge fieldTreated areaha/d5.1348348Application ratekg formulation/ha35010001000500500Active substance%4545454545Frequency-11111Working widthm1512241224M/L time TMLmin960816081Application timeATmin606042060420Breathing volumeBVL/min2020202020M/L, measured concentration in airmg/m30.21 - - - -M/L, expected concentration in airMLECAmg/m3 -0.210.210.210.21Expected dose during M/LMLED MLECA(1000/350) or MLECA(500/350)mg/m3 -0.60.60.30.3Appl. measured concentration in air (open cabin)mg/m30.06 - - - -Appl. measured concentration in air (closed cabin)mg/m30 - - - -Appl. expected concentration in air *AECAmg/m30.0480.07680.0480.0768Expected dose during applicationAEDAECA(1000/350) or AECA(500/350)mg/m31.37E-012.19E-016.86E-021.10E-01Body weightBWkg7070707070Exposure calculation only for inhalation(MLED*BV*TML)+(AED*BV*AT)/(BW/1000)mg/kg bw/d5.40E-041.26E-024.02E-026.32E-032.01E-02LOAELmg/kg bw/d1.30E+001.30E+001.30E+001.30E+001.30E+00AF-3.00E+023.00E+023.00E+023.00E+023.00E+02Systemic AOELmg/kg bw/d4.33E-034.33E-034.33E-034.33E-034.33E-03% AOEL for inhalation only-1.25E+012.92E+029.28E+021.46E+024.64E+02Scenariorealistic worst casenormal case 
 
 
                                          
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

to  estimate  dermal  and  inhalational  exposure  for  professional  operators  when  handling 
and  applying  granular  pesticides.  The  75th  percentile  exposure  values  from  these  data 
subsets  were  used  to  estimate  operator  exposure  resulting  from  uses  of  granular 
formulations  assuming  that  gloves  and  working  clothes  were  worn  for  all  activities. 
However, this model does not foresee using specific values on particle size distribution or 
drift percentage as input values. 

Details  on  the  exposure  calculations  for  the  different  scenarios  are  given  in  Annex  2. 
Table 5 summarises the results. The AOEL is exceeded in all scenarios. 

Table 5: Exposure assessment for workers, inhalation and dermal absorption, based on 
an operator exposure model for granular formulations; gloves and normal work wear 
were worn during loading and application operations and respiratory protection 
equipment was considered for mixing/loading. 

Exposure estimation for private use 

Currently  there  are  no  exposure  models  available  for  predicting  exposure  for  amateur 
users  applying  granules.  In  the  absence  of  specific  exposure  data  for  granule  products, 
the  Puffer pack model  for users  applying  dustable  powder formulations  via puffer packs 
was  recommended  by  the  UK  as  surrogate  data  for  this  exposure  scenario.  This  model 
was used by the SCHER for the exposure assessment of calcium cyanamide fertilisers for 
private  use.  Details  are  provided  in  Annex  3,  table  3.1.  Exposure  was  assumed  to  be 
0.12  mg/kg  bw/d  (>2700%  of  AOEL).  In  addition,  the  Operator  exposure  model  for 
granular  formulations  using  hand-held  application  equipment  was  used,  based  on  the 
assumptions of a 500 m² garden, 180 kg active substance applied per ha and the use of 
protective equipment (see table 3.2). This approach resulted in exposure exceeding the 
AOEL by 32,821%. 

Exposure scenarios for bystanders and residents 

Professional use 

As there were no models available for fertilisers or for granular pesticides, the approach 
for  sprayed  pesticides  was  used  assuming  a  0.2%  drift  to  calculate  exposure  for 
bystanders and residents (Martin, et al., 2008). This percentage was chosen according to 
information provided for the particle size distribution (see Table 1) and on information on 
the amount of fine particles from the CSR. 

Details  for  bystanders  are  provided  in  Annex  4,  table  4.1.  The  values  calculated  for 
bystanders  were  considerably  high,  exceeding  the  systemic  AOEL  for  adults  and  for 
children  when  assuming  exposure  duration  of  5  minutes  as  well  as  10%  dermal 
absorption (Table 6). 

33 

small fieldlarge fieldsmall fieldlarge fieldTotal systemic exposuremg/kg bw/d0.081.210.040.60Percent of AOEL%1,75528,07287714,036EXPOSURE TO GRANULAR FORMULATIONS: VEHICLE-MOUNTED EQUIPMENTRealistic Worst CaseNormal Case 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Table 6: Bystander exposure calculation based on 0.2% drift, a duration of 5 minutes and 
10% dermal uptake 

Calculations  for  residents  included  inhalation  and  dermal  exposure.  For  children  oral 
uptake (hand-to-mouth and object-to-mouth transfer) was also estimated. Based on the 
calculations,  the  uptake  of  calcium  cyanamide  was  high  for  all  scenarios,  exceeding  the 
AOEL.  Results  were  given  in  Table  7  (for  10%  dermal  absorption),  details  of  the 
calculations were provided in Annex 4, Table 4.2. 

Table 7: Residential exposure calculation based on 0.2% drift, a duration of 2 h and 10% 
dermal uptake 

Private use 

No models were available for bystanders during private use, however, it is expected that 
exposure  for  bystanders  would  not  exceed  the  exposure  predicted  for  persons  applying 
the  product.  In  a worst  case  assumption,  exposure  values  for users might  also  be  used 
for bystanders (see above, Exposure estimation for private use). 

Also for private use, inhalation and dermal exposure had to be considered for residents. 
As  there  were  no  models  available,  estimated  exposure  values  for  residents  after 
professional  use  might  be  considered.  A  possible  scenario  of  exposure  during  re-entry 
into  the  treated  areas  and/or  using  treated  areas  as  playgrounds,  sunbathing  meadows 
etc. was not taken into account. 

For  children,  oral  uptake  also  has  to  be  considered  for  products  applied  as  granules  as 
there is a potential for granules to be ingested by children who may enter treated areas 
soon  after  the  they  have  been  applied.  The  UK  developed  a  model  for  oral  uptake  of 
granules by children. This model was used by the SCHER to estimate the additional oral 
exposure  for  children  after  private  use  of  calcium  cyanamide  as  fertiliser.  According  to 
the  amount  applied,  the  additional  oral  exposure  for  children  was  calculated  to  be  0.04 
mg/kg  bw/d  (868%  of  AOEL)  or  0.02  mg/kg  bw/d  (434%  of  AOEL)  depending  on  the 
application rate. For details see table 4.3 in Annex 4. The ingestion of granules would be 
higher for children with pica2 behaviour. 

2 Pica is an eating disorder typically defined as the persistent eating of non-nutritive substances like clay, sand, 
stones and pebbles. 

34 

BystandersAdultsChildrenAdultsChildrenAdultsChildrenAdultsChildrenTotal Systemic Exposuremg/kg bw/d11.4024.14180.15384.445.7012.0790.08192.22Percent of AOEL%265,116561,3384,189,5358,940,581132,558280,6692,094,7674,470,291realistic worst casenormal casesmall fieldlarge fieldsmall fieldlarge fieldResidentsAdultsChildrenAdultsChildrenAdultsChildrenAdultsChildrenTotal Systemic Exposuremg/kg bw/d0,0150,0360,0150,0360,0100,0220,0100,022Percent of AOEL%351840351840224510224510realistic worst casenormal casesmall fieldlarge fieldsmall fieldlarge field 
 
 
 
                                          
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Due to high exposure, the SCHER does not recommend the use of calcium cyanamide as 
fertiliser for private use. 

3.2.9.  Soil, groundwater and surface water, exposure estimates 

3.2.9.1.  Justification Pesticides model used for fertilisers 

The SCHER notes that specific mathematical models for fertilisers are not available in the 
scientific  literature  or  regulatory  frameworks.  It  should  also  be  recognized  that  it  is  not 
with the remit of the SCHER to develop such models for fertilisers. Therefore, the SCHER 
is  of  the  opinion  that  suitable  analogous  procedures/models  should  be  used  to  describe 
the  behaviour and  fate  of  fertilisers.  The  best  available  possibility  is  to  use  models  that 
are  specifically  developed  to  describe  the  behaviour  and  fate  of  chemicals.  In  fact,  a 
fertiliser,  as  a  chemical  substance,  is  subject  to  the  same  degradation,  sorption  and 
leaching  processes  as  all  chemicals.  The  most  advanced  models  have  been  developed 
specifically  for  pesticides  as  their  behaviour  and  fate  is  of  great  importance  for  the 
registration  of  these  chemicals.  In  the  EU,  the  US  and  several  other  countries, 
mathematical models have been developed to help the registration authorities in the risk 
assessment process of pesticides. Examples of these pesticides models can be found on 
the FOCUS-website of the EU (http://focus.jrc.ec.europa.eu/) and for the US on the EPA-
website  (http://www.epa.gov/pesticides/science/models_pg.htm).  These  models  are 
based on the best available scientific knowledge on the fate and behaviour of chemicals 
and make use of generally applicable, accepted, principles. 

The  SCHER  appreciates  the  difference  between  fertilisers  and  pesticides.  Pesticides  are 
used  to  protect  the  growth  of  the  plant  and  to  remove  any  inhibition  of  the  plant 
development  by  pests,  e.g.  weeds,  fungi,  insects,  etc.,  whilst  fertilisers  are  intended  to 
allow  the  full  development  of  the  crop  and  to  increase  the  yield  of  the  harvest.  If, 
however, the type of chemical is considered, there are no principal differences between a 
fertiliser or a pesticide, in the sense that both are mostly (in)organic chemicals that obey 
the general principles of the conservation of mass. Moreover, the application techniques 
used  for  fertilisers  and  pesticides  are  similar.  Both  are  applied  with  the  same  kinds  of 
spraying  equipment.  Therefore,  processes  relevant  for  pesticides,  like  (spray)  drift, 
leaching, runoff, also apply for fertilisers and the same holds for molecular processes like 
degradation  and  sorption.  In  addition  to  these  analogies,  it  should  be  noted  that  the 
environmental  fate  and  behaviour  of  chemicals  is  determined  by  and  can  be  predicted 
from  their  physico-chemical  characteristics,  like  molecular  weight,  solubility,  vapour 
pressure, Henry’s Law constant, pKa, polarity and, of course, the dose of the substance. 
For fertilisers, all these data are available and the application of the models thus leads to 
predictable outcomes. Recognizing these common principles for fertilisers and pesticides, 
the  SCHER  concluded  that  the  use  of  pesticide  models  provides  the  best  available 
approach to describe the fate and behaviour of fertilisers in the environment. 

To  estimate  the  concentrations  in  soil,  groundwater  and  surface  water  after  the 
application  of  calcium  cyanamide  in  cabbage,  the  same  calculation  methods  have  been 
used  by  the  SCHER  as  normally  applied  in  the  evaluation  of  pesticides  in  the  European 
Union. This methodology was called the FOCUS scenarios approach and it had especially 
been  developed  specifically  for  this  purpose  (FOCUS,  2014).  The  following  two  sections 
summarise the results for calcium cyanamide. 

35 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

3.2.9.2.  Estimated PEC in soil 

The SCHER has calculated PEC in soils based on two application rate scenarios. 

The SCHER applied the normal calculation for the determination of the PEC in soil using 
the areic application rate of 225 kg a.s./ha and a depth of 5 cm. Therefore, the resulting 
PECsoil was 0.44 kg calcium cyanamide/m3 or 440 mg/dm3 or assuming a soil density of 
1,500  kg/m3  a PEC  of 300  mg/kg soil.  If  the amount  of  fertiliser  was  ploughed into  the 
soil, assuming a plough depth of 20 cm, the PEC was a factor of 4 lower: 75 mg/kg soil. 
Based on a DT50 in soil of 2 d, the PECsoil and the Time Weighted Average (TWAsoil) was 
estimated and the results are presented in Table 8. 

Table  8  PECsoil  and  TWAsoil  for  cyanamide  in  mg/kg  soil  for  the  normal  scenario 
(application  rate  225  kg  a.s./ha)  and  the  realistic  worst  case  scenario  (application  rate 
450 kg a.s./ha) 

Day 
0 
1 
2 
4 
7 
14 

Normal scenario 
TWA 
PEC 
- 
300 
255 
215 
155 
105 
60 
27 
10 
2.6 
0.5 
0 

Worst case scenario 

PEC 
600 
430 
210 
54 
5.2 

TWA 
- 
510 
310 
120 
20 

3.2.9.3.  Estimated PEC in groundwater 

The concentrations in groundwater after the application of calcium cyanamide in cabbage 
were  calculated  using  the  FOCUS  scenarios.  The  relevant  models  applicable  to 
groundwater  were  downloaded  from  the  FOCUS  website  (FOCUS,  2014)  (MACRO_GW, 
PEARL,  PELMO  and  PRZM_GW).  In  the  following  sections  the  results  for  calcium 
cyanamide  are  summarised  for  seven  different  representative  agricultural  areas  in  the 
EU.  Although  several  models  could  be  used  for  the  estimation  of  the  concentration  of  a 
pesticide  in  groundwater,  the  SCHER  has  chosen  to  apply  the  PEARL  model.  The  input 
data for the model are presented in Table 9. 

Table 9. Input data for model calculations on calcium cyanamide 

Parameter 
Crop 
Location 

Substance Name 
Molecular mass (g mol-1) 
DT50 (d) 
Kom (L kg-1) 
Vapour pressure (Pa) 
Solubility in water (mg L-1) 
Dose (kg.ha-1) as active 
substance 
Interception (-) 

Value 
Cabbage 
Châteaudun, Hamburg, 
Jokioinen, Kremsmuenster, 
Porto, Sevilla, Thiva 
CaCN2 
80.11 
2 
10.5 
0 
29400 
225/450 

0.0 

36 

 
 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

The results of the PEARL calculations are given in Table 10. 

Table 10. PEARL Calculations for calcium cyanamide 

Location 

CHATEAUDUN 
HAMBURG 
JOKIOINEN 
KREMSMUENSTER 
PORTO 
SEVILLA 
THIVA 

Estimated 
groundwater 
concentration 
(µg/L) at normal 
scenario 
0.10 
22 
5 
2.7 
0.18 
0.01 
0.7 

Estimated 
groundwater 
concentration 
(µg/L) at realistic 
worst case scenario 
0.20 
44 
10 
5.4 
0.36 
0.02 
1.4 

According to the registration criteria in the European Union, there should be at least one 
safe  use  for  the  substance  available  in  all  the  European  scenarios.  The  criterion  in  the 
case of groundwater was < 0.1 µg/L. This was the case for Sevilla and Chateaudun. From 
the viewpoint of safety for groundwater the substances could be registered in the EU. In 
other  areas  the  application  of  the  substance  may  be  limited  at  the  national  level  to 
reduce  the  contamination  of  groundwater  as  all  other  estimated  concentrations  were  a 
factor of 7 to 220 higher than the registration criterion. 

A  lysimeter  study  with  calcium  cyanamide  was  carried  out  from  1991  to  1994  (Kubiak, 
1996) using a dosage of 400 kg PERLKA/ha. The study was carried out according to the 
German  Guideline  on  lysimeters  (BBA,  1990).  The  soil  used was  loamy sand with  1.5% 
organic  matter  in  the  upper  30  cm.  All  residues  in  the  leachate  of  the  lysimeters  were 
below 0.1 µg/L. 

The  SCHER  concludes  from  these  results  that  application  of  the  formulation  PERLKA  at 
the recommended dosage does not result in unacceptable concentrations in groundwater. 

3.2.9.4.  Predicted Environmental concentration in surface water 

The FOCUS-models for the surface water compartment were downloaded from the same 
website  (http://focus.jrc.ec.europa.eu/).  It  concerned  the  models  SWASH,  MACRO_SW, 
PRZM_SW and TOXSWA. As the formulation PERLKA is a solid that is applied to the soil 
as  a  granular  product  (AlzChem  Trostberg,  2010)  drift  input  should  not  add  to  the 
contamination  of  surface  water.  This  is  an  accepted  approach  in  the  registration  of 
pesticides and in the SCHER’s opinion it is also applicable for granulated fertilisers. Some 
emission  by  runoff  or  drainage  will  take  place.  Therefore,  calculations  were  carried  out 
with  the  FOCUS  methodology  excluding  drift.  With  the  exception  of  the  locations 
mentioned  in  Table  10,  the  SCHER  used  the  same  input  data  for  the  surface  water 
calculation  as  for  the  groundwater  estimation.  The  FOCUS  surface  water  scenarios 
distinguished  drainage  (D)  and  run-off  (R)  scenarios  which  could  contain  a  ditch  (d),  a 
pond (p) or a small stream (s) as the relevant receiving water bodies. 

The results of the surface water calculations are summarised in the Tables 11, 12, 12A, 
13, 13A, 14, 14A and 15, 15A. 

Table 11. PECsw – FOCUS modelling results for CaCN2 in surface waters at normal and 
realistic worst case scenarios 

37 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Scenario 

Maximum PECsw 
(µg/L) 
at normal scenario 

D3,d 
D4,p 
D4,s 
D5,p 
D5,s 
D6,d 
R1,p 
R1,s 
R2,s 
R3,s 
R4,s 

0.0 
0.006 
0.028 
0.0 
0.0 
7.5 
0.12 
6.6 
220 
2300 
3400 

Maximum PECsw 
(µg/L) 
at realistic worst 
case scenario 
0.0 
0.012 
0.056 
0.0 
0.0 
15 
0.24 
13 
440 
4600 
6800 

D = drainage scenario, R- run-off 
scenario,  d  =  ditch,  p  =  pond 
and s = stream, no cabbage was 
grown in the other D-scenarios. 

More  detailed  results  are  provided  in  the  Tables  12,  12A  and  13,  13A  where  the 
concentrations at the different time points are presented for the normal and the realistic 
worst  case  scenarios.  The  D-  and  R-scenarios  are  given  in  the  Tables  12,  12A  and  13, 
13A respectively. 

Table 12. Detailed calculation results for the PEC in surface waters in drainage scenarios 
in µg/L for the normal application scenario. 

Time (d) 
0 
1 
2 
4 
7 
14 
21 
28 
42 
50 
100 

D3,d 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 

D4,p 
5.95E-03 
5.95E-03 
5.95E-03 
5.90E-03 
5.75E-03 
5.35E-03 
4.80E-03 
4.65E-03 
5.15E-03 
5.40E-03 
1.85E-03 

D4,s 
2.76E-02 
1.65E-02 
1.44E-02 
1.54E-02 
1.75E-02 
2.21E-02 
2.38E-02 
2.45E-02 
2.29E-02 
1.89E-02 
1.90E-02 

D6,d 

D5,p 

D5,s 
0.00E+00  0.00E+00  7.35E+00 
0.00E+00  0.00E+00  7.35E+00 
0.00E+00  0.00E+00  7.30E+00 
0.00E+00  0.00E+00  7.15E+00 
0.00E+00  0.00E+00  6.90E+00 
0.00E+00  0.00E+00  5.80E+00 
0.00E+00  0.00E+00  5.95E+00 
0.00E+00  0.00E+00  3.70E+00 
0.00E+00  0.00E+00  5.10E+00 
0.00E+00  0.00E+00  4.85E+00 
0.00E+00  0.00E+00  4.12E+00 

Table  12A.  Detailed  calculation  results  for  the  PEC  in  surface  waters  in  drainage 
scenarios in µg/L for the realistic worst case application scenario. 

Time (d) 
0 
1 
2 

D3,d 
0.00E+00 
0.00E+00 
0.00E+00 

D4,p 
1.19E-02 
1.19E-02 
1.19E-02 

D4,s 
5.50E-02 
5.50E-02 
5.49E-02 

38 

D5,p 

D5,s 
0.00E+00  0.00E+00  1.47E+01 
0.00E+00  0.00E+00  1.47E+01 
0.00E+00  0.00E+00  1.47E+01 

D6,d 

 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

4 
7 
14 
21 
28 
42 
50 
100 

0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 

1.19E-02 
1.17E-02 
1.15E-02 
1.12E-02 
1.06E-02 
1.05E-02 
1.02E-02 
1.19E-02 

5.48E-02 
5.42E-02 
5.33E-02 
5.10E-02 
4.66E-02 
4.69E-02 
4.33E-02 
5.50E-02 

0.00E+00  0.00E+00  1.46E+01 
0.00E+00  0.00E+00  1.42E+01 
0.00E+00  0.00E+00  1.34E+01 
0.00E+00  0.00E+00  1.32E+01 
0.00E+00  0.00E+00  1.22E+01 
0.00E+00  0.00E+00  1.15E+01 
0.00E+00  0.00E+00  1.03E+01 
0.00E+00  0.00E+00  1.47E+01 

Table 13. Detailed calculation results for the PEC in surface waters in run-off scenarios in 
µg/L for the normal application scenario. 

Time (d) 
0 
1 
2 
4 
7 
14 
21 
28 
42 
50 
100 

R1,p 
1.20E-01 
1.02E-01 
8.65E-02 
6.25E-02 
3.84E-02 
1.05E-02 
2.15E-03 
4.50E-04 
5.00E-05 
0.00E+00 
0.00E+00 

R1,s 
5.65E+00 
2.30E-03 
5.50E-04 
2.00E-04 
5.00E-05 
5.00E-05 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 

R2,s 
2.63E+02 
4.44E-02 
1.71E-02 
6.15E-03 
2.70E-03 
1.10E-03 
5.50E-04 
3.50E-04 
2.00E-04 
1.50E-04 
5.00E-05 

R3,s 
2.28E+03 
2.43E+02 
2.32E+00 
5.80E-01 
2.26E-01 
6.60E-02 
3.47E-02 
2.23E-02 
1.23E-02 
1.04E-02 
3.55E-03 

R4,s 
3.39E+03 
9.35E+00 
7.85E-01 
2.41E-01 
7.50E+01 
1.62E-02 
8.45E-03 
5.45E-03 
2.95E-03 
5.60E-03 
1.90E-03 

Table 13A. Detailed calculation results for the PEC in surface waters in run-off scenarios 
in µg/L for the realistic worst case application scenario. 

Time (d) 
0 
1 
2 
4 
7 
14 
21 
28 
42 
50 
100 

R1,p 
2.40E-01 
2.04E-01 
1.73E-01 
1.25E-01 
7.68E-02 
2.09E-02 
4.30E-03 
9.00E-04 
1.00E-04 
0.00E+00 
0.00E+00 

R1,s 
1.13E+01 
4.60E-03 
1.10E-03 
4.00E-04 
1.00E-04 
1.00E-04 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 

R2,s 
5.26E+02 
8.88E-02 
3.41E-02 
1.23E-02 
5.40E-03 
2.20E-03 
1.10E-03 
7.00E-04 
4.00E-04 
3.00E-04 
1.00E-04 

R3,s 
4.56E+03 
4.85E+02 
4.63E+00 
1.16E+00 
4.52E-01 
1.32E-01 
6.93E-02 
4.46E-02 
2.46E-02 
2.08E-02 
7.10E-03 

R4,s 
6.77E+03 
1.87E+01 
1.57E+00 
4.82E-01 
1.50E+02 
3.24E-02 
1.69E-02 
1.09E-02 
5.90E-03 
1.12E-02 
3.80E-03 

The  tables  14,  14A  and  15,  15A  provide  detailed  results  of  the  calculation  of  the  time-
weighted  average  concentrations  for  the  same  scenarios  and  the  same  application 
scenarios. The TWA concentration  represents  the mean concentration over the specified 
period. 

Table 14. Detailed calculation results for the TWA in surface waters in drainage scenarios 
in µg/L for the normal application scenario. 

Time (d) 

D3,d 

D4,p 

D4,s 

D5,p 

D5,s 

D6,d 

39 

 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

1 
2 
4 
7 
14 
21 
28 
42 
50 
100 

0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 

5.95E-03 
5.95E-03 
5.95E-03 
5.95E-03 
5.85E-03 
5.75E-03 
5.60E-03 
5.30E-03 
5.25E-03 
5.10E-03 

2.75E-02 
2.75E-02 
2.75E-02 
2.74E-02 
2.71E-02 
2.67E-02 
2.55E-02 
2.33E-02 
2.35E-02 
2.17E-02 

0.00E+00  0.00E+00  7.35E+00 
0.00E+00  0.00E+00  7.35E+00 
0.00E+00  0.00E+00  7.35E+00 
0.00E+00  0.00E+00  7.30E+00 
0.00E+00  0.00E+00  7.10E+00 
0.00E+00  0.00E+00  6.70E+00 
0.00E+00  0.00E+00  6.60E+00 
0.00E+00  0.00E+00  6.10E+00 
0.00E+00  0.00E+00  5.75E+00 
0.00E+00  0.00E+00  5.15E+00 

Table 14A. Detailed calculation results for the TWA in surface waters in drainage 
scenarios in µg/L for the worst case application scenario. 

Time (d) 
1 
2 
4 
7 
14 
21 
28 
42 
50 
100 

D3,d 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 
0.00E+00 

D4,p 
1.19E-02 
1.19E-02 
1.19E-02 
1.19E-02 
1.17E-02 
1.15E-02 
1.12E-02 
1.06E-02 
1.05E-02 
1.02E-02 

D4,s 
5.50E-02 
5.50E-02 
5.49E-02 
5.48E-02 
5.42E-02 
5.33E-02 
5.10E-02 
4.66E-02 
4.69E-02 
4.33E-02 

D5,p 

D6,d 

D5,s 
0.00E+00  0.00E+00  1.47E+01 
0.00E+00  0.00E+00  1.47E+01 
0.00E+00  0.00E+00  1.47E+01 
0.00E+00  0.00E+00  1.46E+01 
0.00E+00  0.00E+00  1.42E+01 
0.00E+00  0.00E+00  1.34E+01 
0.00E+00  0.00E+00  1.32E+01 
0.00E+00  0.00E+00  1.22E+01 
0.00E+00  0.00E+00  1.15E+01 
0.00E+00  0.00E+00  1.03E+01 

Table 15. Detailed calculation results for the TWA in surface waters in run-off scenarios 
in µg/L for the normal application scenario. 

Time (d) 
1 
2 
4 
7 
14 
21 
28 
42 
50 
100 

R1,p 
1.12E-01 
1.04E-01 
8.95E-02 
7.35E-02 
4.87E-02 
3.44E-02 
2.61E-02 
1.75E-02 
1.47E-02 
7.35E-03 

R1,s 
2.93E+00 
1.47E+00 
7.35E-01 
4.19E-01 
2.10E-01 
1.40E-01 
1.05E-01 
7.00E-02 
5.85E-02 
2.94E-02 

R2,s 
1.23E+02 
6.10E+01 
3.06E+01 
1.75E+01 
9.10E+00 
6.05E+00 
4.54E+00 
3.03E+00 
2.54E+00 
1.27E+00 

R3,s 
1.86E+03 
9.65E+02 
4.82E+02 
2.76E+02 
1.38E+02 
9.20E+01 
6.90E+01 
4.60E+01 
3.87E+01 
1.93E+01 

R4,s 
2.42E+03 
1.21E+03 
6.05E+02 
3.46E+02 
1.77E+02 
1.18E+02 
8.85E+01 
5.90E+01 
4.95E+01 
2.48E+01 

Table 15A. Detailed calculation results for the TWA in surface waters in run-off scenarios 
in µg/L for the worst case application scenario. 

Time (d) 
1 
2 
4 
7 
14 

R1,p 
2.23E-01 
2.07E-01 
1.79E-01 
1.47E-01 
9.73E-02 

R1,s 
5.86E+00 
2.93E+00 
1.47E+00 
8.38E-01 
4.19E-01 

R2,s 
2.45E+02 
1.22E+02 
6.12E+01 
3.50E+01 
1.82E+01 

R3,s 
3.72E+03 
1.93E+03 
9.64E+02 
5.51E+02 
2.76E+02 

R4,s 
4.83E+03 
2.42E+03 
1.21E+03 
6.91E+02 
3.54E+02 

40 

 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

21 
28 
42 
50 
100 

6.87E-02 
5.21E-02 
3.49E-02 
2.93E-02 
1.47E-02 

2.79E-01 
2.10E-01 
1.40E-01 
1.17E-01 
5.87E-02 

1.21E+01 
9.08E+00 
6.05E+00 
5.08E+00 
2.54E+00 

1.84E+02 
1.38E+02 
9.20E+01 
7.73E+01 
3.86E+01 

2.36E+02 
1.77E+02 
1.18E+02 
9.90E+01 
4.95E+01 

These  tables  show  that  especially  in  scenarios  D6,  R2,  R3  and  R4,  the  concentration  of 
calcium cyanamide is high compared to that in the other scenarios. This is mainly caused 
by  the  low  organic  carbon  content  of  these  scenarios,  except  for  R2  where  the  steep 
slope  of  the  field,  which  leads  to  higher  run  off  rates,  is  the  main  reason  for  the  high 
concentration. 

3.2.9.5.  Estimated concentration in air 

The formulation PERLKA was applied to soil as a granulated product. The vapour pressure 
of  the  a.s.  calcium  cyanamide  was  very  low  (estimated  with  EpiSuite:  4.58E-19  Pa). 
Therefore,  the  SCHER  concluded  that  the  air  compartment  is  not  relevant  and  should 
therefore not be considered in estimating exposures except for the scenarios discussed in 
paragraph 3.2.8. 

3.3. Risk Assessment 

3.3.1.  Human Health Risk Assessment 

The  SCHER  evaluated  data  available  on  toxicity  of  calcium  cyanamide  as  well  as  on 
cyanamide in an overall weight of evidence approach in order to assess possible effects 
on  the  human  health  from  the  use  of  calcium  cyanamide  as  a  fertiliser.  As  calcium 
cyanamide  was  hydrolysed  to  cyanamide  after  oral  administration  in  experimental 
animals as well as in humans, toxic effects observed for calcium cyanamide were mainly 
attributable  to  cyanamide  toxicity.  The  SCHER  has  selected  a  LOAEL  of  1.3  mg  calcium 
cyanamide/kg bw/d from a rat study and derived a provisional AOEL of 4.3 µg/kg bw/d 
based  on  a  safety  factor  of  300.  Developmental  toxicity  with  reduced  foetal  weight  has 
been observed above doses of 7 mg/kg bw/d, but with no excess mortality and no signs 
of teratogenicity at doses as high as 49 mg/kg bw/day. 

For  the  exposure  assessment,  the  SCHER  calculated  scenarios  for  the  different  uses  of 
calcium  cyanamide  as  a  fertiliser,  based  on  data  measured  for  inhalation  exposure  as 
well  as  on  the  basis  of  default  values  attributed  to  exposure  calculation  models  judged 
appropriate  for  granulated  materials.  Exposure  calculations  were  performed  for  both 
professional  and  private  use  scenarios  and  additionally  for  bystanders  and  residents, 
including  children.  For  all  scenarios,  the  AOEL  is  exceeded  (see  Table  16).  Some  of  the 
model scenarios might overestimate the actual exposure, but on the other hand, on the 
basis  of  measured  data,  the  AOEL  is  already  exceeded  when  considering  the  inhalation 
exposure only. 

Table 16: Percent of AOEL for different exposure scenarios 
1 calculated with the UK models  
2 calculated on base of data measured (inhalatory exposure only) 
3 oral uptake of treated soil and granulate only  
i = inhalatory, d = dermal, o = oral, n.d. = no data from models 

41 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

3.3.2.  Environmental Risk Assessment 

Soil 

Several  organisms  were  considered  for  the  soil  compartment:  birds,  earthworms,  non-
target arthropods and microorganisms. 

For birds, the toxicity test on feed avoidance behaviour showed that birds did not feed on 
the PERLKA granules. In the evaluation of hydrogen cyanamide by EFSA (EFSA, 2012) a 
risk for birds was identified due to the soluble formulation used. The SCHER, however, is 
of the opinion that because of the granular formulation and the birds’ feeding avoidance, 
exposure is unlikely to occur and therefore birds are not considered at risk. 

The  risk  assessment  for  earthworms  was  based  on  the  estimated  environmental 
concentrations given in Table 9 and the ecotoxicity data presented in section 3.2.6.2. An 
assessment  factor  of  10  as  normally  used  in  the  registration  procedure  for  plant 
protection products in the EU was applied to the ecotoxicity data. The SCHER concluded 
that for this compartment risks cannot be excluded after the application of cyanamide at 
the recommended dosage of 225 kg a.s./ha (Table 17). RCRaAF and RCRtwaAF stand for 
the calculated risk characterisation ratio after  acute exposure or time weighted average 
exposure.  The  time-weighted  average  concentration  at  t  =  0  was  not  defined.  A 
reduction by a factor of about 15 to 20 would reduce the risk to a level without concern. 

Table 17. Risk assessment for earthworms 

At normal application 
rates 

At realistic worst case 
applications 

Day 

RCRaAF 

RCRtwaAF  RCRaAF 

RCRtwaAF 

0 

1 

2 

4 

7 

14 

17.40 

12.30 

6.15 

1.54 

0.14 

0.00 

14.70 

8.87 

3.33 

0.58 

0.03 

35.52 

25.12 

12.56 

3.14 

0.28 

0.00 

30.02 

18.12 

6.79 

1.18 

0.06 

In a field study carried out in 1991 and 1992 (Bauchhenẞ, 1994) with a somewhat lower 
application  rate (400 kg  formulation/ha compared  to  the  normal  application  rate of  500 
or the worst-case application rate of 1000 kg formulation/ha) no effects on earthworms 
were  observed.  Despite  this  shortcoming  of  the  study  the  SCHER  is  of  the  opinion  that 
most probably effects on earthworms may be considered negligible. 

The SCHER’s opinion with respect to exposures to beetles is that the risks cannot yet be 
completely  excluded  as  only  1  dosage  had  been  tested  at  450  kg  formulation/ha.  The 

42 

ExposureOperator ModelPuffer Pack Modelsmall fieldlarge fieldsmall fieldlarge fieldoperator1i, d1,75528,07287714,03632,8212,761operator2i 292928146464 - -bystander adulti, d265,1164,189,535132,5582,094,767n.d.n.d.bystander childi, d561,3388,940,581280,6694,470,291n.d.n.d.resident adulti, d351351224224n.d.n.d.resident childi, d, o840840510510n.d.n.d.resident child3o - - - -Professional usePrivate use434-868realistic worst casenormal case 
 
 
  
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

normal dosage was however 500 kg/ha. The SCHER considered the normal dose and the 
tested  dose  sufficiently  close  that  effects  may  be  not  likely.  A  new  study  at  normal 
application rates is recommended. 

No toxicity data of calcium cyanamide to bees were available to the SCHER. Therefore no 
risk assessment could be carried out. However, the SCHER is of the opinion that bees will 
not be exposed during the time of application. 

Finally, the SCHER concluded that for microorganisms risks were not expected as effects 
have only been determined at rates 5 times higher than the normal dosage. 

Groundwater 

Table  10  presents  data  for  several  locations  across  the  European  Union  which  were 
considered  representative  for  the  cultivation  of  cabbage.  This  table  indicates  that  the 
concentration in groundwater may exceed the allowable concentration in groundwater of 
0.1  g/L. In areas with low organic matter contents the exceedance might be more than 
a  factor  of  200  in  the  normal  application  scenario  (e.g.  22  µg/L  has  been  calculated  in 
the Hamburg scenario; Table 10) and even more than 400 in the situation of a realistic 
worst  case  application  scenario.  Therefore,  the  SCHER  concluded  that  concentrations  in 
groundwater  occur  after  the  application  of  calcium  cyanamide  (according  to  normal 
application  rates)  may  pose  a  risk.  SHER  notes  that  even  at  much  lower  application 
rates, in some areas, existing guideline values will be exceeded. 

However,  a  lysimeter  study  with  calcium  cyanamide  was  carried  out  that  showed  all 
concentrations  in  the  leachate  below  the  guideline  value  of  0.1  µg/L.  (AlzChem 
Trostberg,  2015)  Therefore,  the  SCHER  concludes  that  groundwater  will  not  be  at  risk 
after the application of calcium cyanamide at normal application rates. 

Surface water 

The  environmental  risk  assessment  conducted  here  used  the  methodology  described  in 
the EFSA Guidance Document on aquatic ecotoxicology (EFSA, 2013). In section 3.2.6.1 
the  relevant  acute  endpoints  for  three  aquatic  species  were  determined.  The  PNEC  was 
derived  by  dividing  the  lowest  L(E)C50  of  the  three  test  species  by  100.  The  lowest 
short-termL(E)C50 in Table 2 is 6 mg/L. the SCHER thus derived a PNEC of 60 µg/L and 
used this value in the further risk calculations 

Tables  18  to  21,  using  normal  applications  rates,  and  Tables  18A  to  21A,  using  the 
realistic  worst  case  applications  rates,  present  the  results  of  the  risk  assessment  for 
calcium cyanamide based on the PEC established with the FOCUS surface water scenarios 
and  the  derived  PNEC.  The  safe  values  are  indicated  in  green,  and  the  values 
representing  a  risk  in  red.  The  SCHER  concludes  that  the  application  of  calcium 
cyanamide as a fertiliser might lead to risk for aquatic organisms, especially as the Risk 
Characterisation Ratios (RCRs) > 1 by more than a factor of 10 in many cases. 

43 

 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Table 18A. Risk Characterisation Ratios for the PECs in drainage scenarios at normal 
application scenario 

Table 18B. Risk Characterisation Ratios for the PECs in drainage scenarios at realistic 
worst case application scenario 

Table 19A. Risk Characterisation Ratios for the PECs in runoff scenarios at normal 
application scenario 

44 

Time (d)D3,dD4,pD4,sD5,pD5,sD6,d00.000.000.000.000.000.1210.000.000.000.000.000.1220.000.000.000.000.000.1240.000.000.000.000.000.1270.000.000.000.000.000.12140.000.000.000.000.000.10210.000.000.000.000.000.10280.000.000.000.000.000.06420.000.000.000.000.000.09500.000.000.000.000.000.081000.000.000.000.000.000.07Time (d)D3,dD4,pD4,sD5,pD5,sD6,d00.000.000.000.000.000.2510.000.000.000.000.000.2520.000.000.000.000.000.2440.000.000.000.000.000.2470.000.000.000.000.000.23140.000.000.000.000.000.19210.000.000.000.000.000.20280.000.000.000.000.000.12420.000.000.000.000.000.17500.000.000.000.000.000.161000.000.000.000.000.000.14Time (d)R1,pR1,sR2,sR3,sR4,s00.000.094.3838.0056.4210.000.000.004.040.1620.000.000.000.040.0140.000.000.000.010.0070.000.000.000.001.25140.000.000.000.000.00210.000.000.000.000.00280.000.000.000.000.00420.000.000.000.000.00500.000.000.000.000.001000.000.000.000.000.00 
 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Table 19B. Risk Characterisation Ratios for the PECs in runoff scenarios at realistic worst 
case application scenario 

Table 20A. Risk Characterisation Ratios for the TWAs in drainage scenarios at normal 
application scenario 

Table 20B. Risk Characterisation Ratios for the TWAs in drainage scenarios at realistic 
worst case application scenario 

45 

Time (d)R1,pR1,sR2,sR3,sR4,s00.000.198.7776.00112.8310.000.000.008.080.3120.000.000.000.080.0340.000.000.000.020.0170.000.000.000.012.50140.000.000.000.000.00210.000.000.000.000.00280.000.000.000.000.00420.000.000.000.000.00500.000.000.000.000.001000.000.000.000.000.00Time (d)D3,dD4,pD4,sD5,pD5,sD6,d10.000.000.000.000.000.1220.000.000.000.000.000.1240.000.000.000.000.000.1270.000.000.000.000.000.12140.000.000.000.000.000.12210.000.000.000.000.000.11280.000.000.000.000.000.11420.000.000.000.000.000.10500.000.000.000.000.000.101000.000.000.000.000.000.09Time (d)D3,dD4,pD4,sD5,pD5,sD6,d10.000.000.000.000.000.2520.000.000.000.000.000.2540.000.000.000.000.000.2570.000.000.000.000.000.24140.000.000.000.000.000.24210.000.000.000.000.000.22280.000.000.000.000.000.22420.000.000.000.000.000.20500.000.000.000.000.000.191000.000.000.000.000.000.17 
 
 
 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Table 21A. Risk Characterisation Ratios for the TWAs in runoff scenarios at normal 
application scenario 

Table 21B. Risk Characterisation Ratios for the TWAs in runoff scenarios at realistic 
worst case application scenario 

The SCHER concludes on the basis of the results of tables 18A to 221A and 18B to 21B 
that  after  application  of  PERLKA  up  to  a  dosage  of  500  kg/ha  in  drainage  regions 
probably  no  risk  for  aquatic  organisms  will  occur.  However,  in  runoff  areas  the  SCHER 
concludes  that  risks  for  aquatic  organisms  cannot  be  excluded  as  exceedance  of  risk 
characterisation ratios up to a factor of 56 may occur. 

3.4. Conclusions on data 

3.4.1.  Human health 

Overall,  the  SCHER  is  of  the  opinion  that  at  the  present  rate  of  application  common  in 
agricultural practice, there is a risk for operators using calcium cyanamide as a fertiliser. 
The models used for the exposure calculation for professional use took into account the 
use  of  protective  gloves  and  work  clothes.  The  use  of  masks  during  application  might 
reduce the risk of operators but was not recommended as: 

• 

• 

• 

the use of masks might not be practical under real conditions when applying 
fertilisers; 
the  use  of  masks  during  professional  use  was  irrelevant  for  protection  of 
private users, bystanders or residents; 
the  professional  application  of  calcium  cyanamide  as  fertiliser  additionally 
posed a risk for bystanders and residents. 

46 

Time (d)R1,pR1,sR2,sR3,sR4,s10.000.052.0431.0040.2520.000.021.0216.0820.1740.000.010.518.0310.0870.000.010.294.595.76140.000.000.152.302.95210.000.000.101.531.97280.000.000.081.151.48420.000.000.050.770.98500.000.000.040.640.831000.000.000.020.320.41Time (d)R1,pR1,sR2,sR3,sR4,s10.000.104.0862.0080.5020.000.052.0332.1740.3340.000.021.0216.0720.1770.000.010.589.1811.52140.000.010.304.605.90210.000.000.203.073.93280.000.000.152.302.95420.000.000.101.531.97500.000.000.081.291.651000.000.000.040.640.83 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

The private use of calcium cyanamide as fertiliser should be avoided, also with respect to 
the  toxic  properties  of  cyanamide.  The  risk  for  bystanders  as  well  as  for  residents  re-
entering  treated  areas  could  not  be  calculated.  For  children  playing  on  treated  areas, 
exposure  was  estimated  to  pose  a  risk.  The  exposure  to  calcium  cyanamide  from  a 
possible oral uptake of granules by children was calculated and exceeded the AOEL. 

3.4.2.  Environment 

The  environmental  data  in  the  registration  dossier  for  the  fertiliser  calcium  cyanamide 
are considered by the SCHER to be of sufficient quality to be used in a risk assessment 
as carried out in this opinion. The SCHER accepts the waivers of the manufacturer on the 
chronic toxicity for aquatic organisms based on the rather quick degradation of the active 
substance  calcium  cyanamide  into  cyanamide  and  urea  with  the  final  degradation 
products  CO2,  NO3  and  H2O  (see  the  degradation  scheme  in  Figure  1).  The  SCHER  has 
chosen  to  use  the  toxicity  data  for  calcium  cyanamide  as  the  most  appropriate  for  the 
risk  assessment,  mainly  because  the  effects  of  the  substance  after  application  were 
shown  in  the  first  couple  of  days,  although  some  do  prolong  as  far  as  50  days  after 
application.  The  application  took  place  only  once  a  year  and  before  sowing.  The 
information  provided  by  the  manufacturer  in  leaflets,  however,  shows  that  in  several 
applications a dosage before and after sowing is recommended. 

Based on the dossier provided by the manufacturer the SCHER concluded that potential 
risks for aquatic organisms cannot be excluded. For other terrestrial organisms, like birds 
and  non-target  arthropods  no  risks  are  expected  at  normal  application  rates  of  calcium 
cyanamide.  Also  risks  to  microorganisms  were  not  expected.  No  information  was 
available about the toxicity and potential risks of calcium cyanamide to bees.  

According to the SCHER, normal risk mitigation measures, like reduction of the dose, and 
drift reduction are expected to be insufficient to reduce all risks indicated. It is especially 
difficult  to  reduce  the  risk  to  groundwater  contamination  in  all  scenarios.  However,  a 
lysimeter  study  carried  out  between  1991  and  1994  indicated  that  the  concentration  in 
the  leachate  in  the  soils  applied  was  below  0.1  µg/L.  Probably,  groundwater 
contamination  might  be  lower  than  expected,  although  in  other  soils,  e.g.  with  less 
organic matter, groundwater contaminations at levels that can pose risks may still occur. 
The  SCHER  is  of  the  opinion  that  additional  studies  may  provide  more  insight  into  the 
realism of the anticipated risks. This would imply that for the aquatic compartment field 
studies  or  mesocosm  studies  could  be  carried  out  to  prove  that  no  effects  for  aquatic 
organisms  detected.  For  bees,  the  basic  toxicity  tests  were  missing  and  appropriate 
testing should be carried out. In addition, field studies would be required to demonstrate 
that no adverse effects to beetles occur. 

3.4.3.  Uncertainties 

The  primary  data  as  presented  by  the  manufacturer  in  the  registration  dossier  might 
have some inherent uncertainty. The SCHER has taken into account uncertainties in the 
usual manner that uncertainties are accounted for in regulatory risk assessment, i.e. by 
factors  and  adopting  common  risk  assessment 
using  appropriate  assessment 
methodologies.  However,  the  risk  assessment  methods  used  by  the  SCHER  and 
developed  for  estimating  environmental  exposure  and  human  exposure  to  pesticides 
might  also  have  some  inherent  uncertainty.  Nevertheless,  the  SCHER  is  of  the  opinion 
that  based  on  the  information  and  tools  available,  the  best  possible  risk  assessment 
approach has been used in this opinion. 

47 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

4.  OPINION OF THE SCHER 

4.1. Question 1 of ToR 

Taking  into  account  all  relevant  information  that  was  available  before  1  April 
2015,  can  the  use  of  both  the  powdered  and  granulated  form  of  calcium 
cyanamide be considered safe for human health and the environment? 

The SCHER concluded after receiving additional information from the manufacturer that a 
dosage of 1,000 kg PERLKA/ha is a realistic worst case scenario whilst the normal dosage 
is considered to be 500 kg PERLKA/ha. The results of the risk assessment presented are 
based on both application rates. The SCHER based its evaluation on the granulated form 
and was not able to exclude potential effects for human health nor for the environment. 
In the case of the powdered form the SCHER considered that the risk for human health 
would increase because of a higher fraction of small size particles in the powdered form. 
For  the  environment,  the  risks  identified  for  the  powdered  form  are  the  same  as  those 
identified for the granulated form because of the assumption of no drift. 

Currently  there  are  no  exposure/risk  models  available  for  the  evaluation  of  fertilisers. 
Therefore,  the  SCHER  calculated  the  exposure  based  on  measured  data  and  in  addition 
used  exposure  models  developed  for  pesticides  as  the  most  appropriate  tools  available. 
Using  these  models,  the  SCHER  concluded  that  harmful  effects  for  humans  and  for  the 
environment could not be excluded at normal and at the realistic worst-case applications. 
Risks were identified in both scenarios for the end-users (famers as well as private users) 
and  for  residents  and  bystanders  including  children.  For  the  environment,  the  SCHER 
identified risks for the aquatic compartment in both scenarios. 

4.2. Question 2 of ToR 

In  case  of  risks  identified  by  the  SCHER,  are  the  protective  measures 
recommended  by  the  manufacturer  sufficient  to  ensure  a  safe  use  of  calcium 
cyanamide as fertiliser? 

The  manufacturer  provided  recommendations  for  using  gloves  and  work  clothes  to 
protect  operators.  Despite  the  use  of  these  protective  measures,  risks  have  been 
identified as all models used by the SCHER for the exposure calculation for professional 
and private use took into account the use of protective gloves and work clothes. The use 
of  masks  by  operators during  application  might  further  reduce the  risk  of  operators but 
might not be practical under real use conditions. 

In addition to the risks to operators, the SCHER identified health risks to bystanders and 
residents. In contrast to operators, there were no protective measures available for these 
groups. 

Although  the  SCHER  also  used  some  conservative  approaches  for  its  exposure 
assessment,  the  assumptions  made  were  not  unrealistic.  In  all  scenarios  the  AOEL  was 
exceeded considerably. On the basis of the current available knowledge, a concentration 
of  calcium  cyanamide  in  a  fertiliser  formulation  not  posing  a  health  risks  for  humans 
could not be derived. Additionally it needs to be kept in mind, that the main metabolite of 
calcium  cyanamide  is  hydrogen  cyanamide,  which  was  already  restricted  for  use  as  a 
pesticide due to health risks. 

48 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

The private use of calcium cyanamide as fertiliser should be avoided for several reasons, 
i.e. (1) AOEL was exceeded in all scenarios even when considering the use of gloves and 
work  clothes,  (2)  there  were  no  additional  protective  measures  available  for  private 
users,  (3)  there  was  an  unknown  risk  regarding  re-entry  and  use  of  treated  garden 
areas,  (4)  oral  uptake  of  treated  soil  and  granulate  by  children  already  exceeded  the 
AOEL. 

The manufacturer did not provide recommendations for protecting the environment. 

4.3. Question 3 of ToR 

In  case  of  potential  risk  for  the  environment,  which  application  rate  per 
concerned crops would not create any detrimental effect under the relevant soil 
and climatic conditions? 

The  SCHER  calculated  risks  based  on  an  application  rate  of  500  kg  formulation/ha  on 
several  crops.  For  lower  and  higher  application  rates,  the  models  predicted  a  linear 
exposure relationship. 

To  ensure  environmental  safety,  the  SCHER  first  considered  the  RCRs  obtained.  The 
RCRs  calculated  were different  for  the  different  environmental  compartments  taken  into 
account.  In  order  to  reduce  the  risk  characterisation  ratio  to  1  (i.e.  to  avoid  any 
detrimental  effect  to  the  aquatic  compartment)  an  application  rate  of  4  kg  of  a.s./ha  is  
required (9 kg of formulation/ha). 

4.4. Question 4 of ToR 

In  case  major  gaps  are  identified  in  the  scientific  knowledge  of  the  hazard  or 
exposure  associated  with  the  use  of  calcium  cyanamide,  how  does  the  SCHER 
suggest to close those gaps within a reasonable period of time? 

With regard to human health risks, exposure data measured under normal use conditions 
(application  of  500  kg  formulation/ha,  treatment  of  a  field  with  an  adequate  size, 
determination  of  drift)  should  be  generated  in  order  to  refine  the  exposure  assessment 
for operators, bystanders and residents.  

The  SCHER  recommends  chronic  toxicity  studies  to  be  conducted  which  will  provide 
robust data that allow the derivation of a NOAEL. 

For  the  environment,  the  SCHER  identified  a  lack  of  appropriate  models  for  the 
evaluation  of  exposure  to  fertilisers.  For  example,  an  adapted  version  of  the  FOCUS 
models relevant for fertilisers could be developed and would be highly relevant for future 
risk evaluation of fertilisers in general. 

As  the  risks  for  the  aquatic  compartment  identified  by  the  SCHER  are  based  solely  on 
acute  toxicity  data  (no  other  reliable  ecotoxicological  data  were  available),  the  SCHER 
recommends additional chronic and higher tier ecotoxicity testing to allow a reduction of 
the  uncertainties  in  the  current  effect  assessment.  It  should  be  noted  that  for  all  the 
additional studies, recommended test guidelines or protocols are available for pesticides 
and can be adapted for use with fertilisers. 

In this respect, the SCHER considers 2 years as a reasonable period of time to close the 
gaps. 

49 

 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

5.  MINORITY OPINION 

None. 

50 

 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

6.  COMMENTING PERIOD 

A  commenting  period  on  this  Opinion  was  opened  on  the  website  of  the  non-food 
scientific committees from 6 November 2015 to 10 January 2016.  

Contributions  from  4  stakeholders  were  received  in  this  commenting  period.  Each 
contribution  was  carefully  considered  by  the  SCHER  and  where  appropriate,  the  text  of 
the  Opinion  has  been  modified  or  explanations  have  been  added  to  take  account  of 
relevant  comments.  The  reference  list  has  been  accordingly  updated  with  relevant 
publications.  The  scientific  rationale  and  the  Opinion  section  were  clarified  and 
strengthened.  In  cases  where  the  SCHER,  after  consideration  and  discussion  of  the 
comments,  decided  to  maintain  its  initial  views,  the  Opinion  (or  the  section  concerned) 
has remained unchanged.  

51 

 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

7.  LIST OF TERMS AND ABBREVIATIONS 

AOEL 

a.s. 

BCOP 

bw 

Cah 

Acceptable Operator Exposure Level 

Active Substance 

Bovine Corneal Opacity and Permeability Study in vitro 

body weight  

cyanamide hydratase 

CaCN2 

calcium cyanamide 

CAS 

d 

dw 

DCD 

DT50 

DT90 

EC 

ECDC 

ECHA 

EFSA 

EMA 

Chemical Abstract Services 

day 

dry weight 

dicyandiamide  

Time to degrade 50% of the substance (d) 

Time to degrade 90% of the substance (d) 

European Commission 

European Centre for Disease prevention and Control 

European Chemicals Agency 

European Food Safety Authority 

European Medicines Agency 

EPIWIN 

US-model to determine chemical properties 

EU 

European Union 

FOCUS 

Forum for the coordination of pesticide models and their use 

GLP 

GPMT 

h 

ha 

Good Laboratory Practice 

modified guinea pig maximisation test 

hour 

Hectare 

HPLC 

High-performance liquid chromatography 

Kalkstickstoff  Formulation name of calcium cyanamide in powder form 

LC50 

LD50 

lethal concentration for 50% of the population 

lethal dose for 50% of the population 

LOAEL 

lowest observed adverse effect level 

MAK 

Maximale Arbeitsplatz-Konzentration (German: maximum workplace 
concentration) 

NCI 

National Cancer Institute 

52 

 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

NOAEL 

No Observed Adverse Effect Level 

NOEC 

OECD 

PEC 

No Observed Effect Concentration 

Organization for Economic Cooperation and Development 

Predicted Environmental Concentration 

PERLKA 

formulation name of calcium cyanamide in granular form 

PNEC 

Predicted No Effect Concentrations 

PPP 

RCR 

Plant Protection Product 

Risk Characterization Ratio 

REACH 

Registration, Evaluation and Authorisation of Chemicals 

SCCS 

Scientific Committee on Consumer Safety 

SCENIHR 

Scientific Committee on Emerging and Newly Identified Health Risks 

SCHER 

Scientific Committee on Health and Environmental Risks 

ToR 

Terms of Reference 

53 

 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

8.  REFERENCES 

AlzChem Trostberg (2010). Registration dossier for Fertiliser Registration. 

Allan S A (1992). Calcium cyanamide, technical grade: Acute oral toxicity to the mouse. 
Huntingdon  Research  Centre  Ltd.,  P.O.  Box  2,  Huntingdon,  Cambridgeshire,  PE18  6ES, 
England. Study report 920232D/STB12/AC. 

AlzChem  (2013).  Calcium  cyanamide  PERLKA  http://www.AlzChem.com/en/markets-
products/agriculture/calcium-cyanamide-PERLKA (accessed Dec 2013). 

Appelman  L  M  (1978).  Acute  inhalation  toxicity  study  of  Kalkstickstoff  in  rats.  Centraal 
Instituut  Voor  Voedingsonderzoek,  TNO,  Utrechtseweg  48,  Zeist,  Netherlands.  Study 
report R 5736. 

Appelman  L  M  (1979).  Acute  inhalation  toxicity  study  of  0.5%  oiled  Kalkstickstoff  in 
combination  with  oral  administration  of  ethanol  in  rats.  Centraal  Instituut  Voor 
Voedingsonderzoek, TNO, Utrechtseweg 48, Zeist, Netherlands. Study report R 6025. 

BBA (1990) Guideline on Lysimeters. 

Benitz  K  F  and  Salamandra I A  (1960).  Calcium  Cyanamide:  Morphological  Studies  of  a 
One-year  Toxicity  Experiments  in  Rats.  Lederle  Laboratories,  Pearl  River,  New  York, 
Experimental  Therapeutics  Research,  Departure  of  Experimental  Pathology  and 
Pharmacological Research. Study report, project number 18785. 

Benitz K F and Takesue E (1960). Calcium Cyanamide: Six-Month Oral Toxicity Study of 
Calcium  Cyanamide  in  Dogs.  Lederle  Laboratories,  Pearl  River,  New  York,  Experimental 
Therapeutics  Research,  Departure  of  Experimental  Pathology  and  Pharmacological 
Research. Study report, research project numbers 18785 and 14785. 

Benitz  K  F  and  Tonelli  G  (1957).  Toxicity  Studies  of  Calcium  Cyanamide  (Ag  5738). 
Range-Finding  Experiment  of  Calcium  Cyanamide  (Ag  5738)  in  Rats.  Pearl  River 
Laboratories,  Experimental  Therapeutics  Research  Section,  Experimental  Pathology  and 
Pharmacological Research Departments. Study report, project number 785. 

Benitz K F, Kramer A W, Dambach J R, Dambach G (1965). Comparative Studies on the 
Morphologic  Effects  of  Calcium  Carbimide,  Propylthiouracil,  and  Disulfiram  in  Male  Rats. 
Tox. Appl. Pharm. 7, 128-162. 

Benitz  K  F  and  Cavallo  M  A  (1960).  Five-Month  Toxicity  Study  in  Rats.  Lederle 
Laboratories,  Pearl  River,  New  York,  Experimental  Therapeutics  Research,  Departure  of 
Experimental  Pathology  and  Pharmacological  Research.  Study  report,  project  number 
785. 

Berger I (1966). Toxicity Studies of Calcium Cyanamide. The acute oral toxicity of citric 
acid (CL 9059); calcium cyanamide (CL 30,524); a 2:1 mixture of citric acid and calcium 
cyanamide;  and  Temposil  (R)  milled  tablet  powder  in  adult  male  rats.  Lederle 
Laboratories,  Pearl  River,  New  York,  Experimental  Therapeutics  Research,  Departure  of 
Experimental Pathology and Pharmacological Research. Study report 4372C LL977. 

Bourbos  V  A,  Skoudridakis  M  T,  Darakis  G  A,  Koulizakis  M  (1997).  Calcium  cyanamide 
and  soil  solarization  for  the  control  of  Fusarium  solanif.  sp.  cucurbitae  in  greenhouse 
cucumber. Crop Protection, 16, 383–386. 

Brien  J  F  and  Loomis  C  W  (1983).  Disposition  and  Pharmacokinetics  of  Disulfiram  and 
Calcium Carbimide (Calcium Cyanamide). Drug Metabolism Reviews, 14 (1), 113-126. 

54 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Colom  H,  Prunonosa  J,  Peraire  C,  Domenech  J,  Azcona  O,  Torrent  J,  Obach  R  (1999). 
Absolute bioavailability and absorption profile of cyanamide in man. J. Pharmacokinetics, 
Biopharmaceutics, 27 (4), 422-436. 

De  Groot  A  P  (1976).  Determination  of  the  acute  oral  toxicity  of  technical  calcium 
cyanamide  in  rats.  Centraal  Instituut  Voor  Voedingsonderzoek,  Utrechtseweg  48,  Zelst, 
Netherlands. Study report. 

De  Raat  W  K  (1979).  An  investigation  into  the  sister  chromatide  exchange  induction  in 
chinese  hamster  ovary  cells  by  a  sample  of  "Kalkstickstoff".  TNO,  Organisation  for 
industrial  research,  P.  O.  Box  217,  Schoemaakerstraat  97,  2600  AE  Delft,  The 
Netherlands. Study report CL/78/120.  

DeMaster  E  G,  Redfern  B,  Nagasawa  H  T  (1998).  Mechanisms  of  inhibition  of  aldehyde 
dehydrogenase  by  nitroxyl,  the  active  metabolite  of  the  alcohol  deterrent  agent 
cyanamide. Biochemical Pharmacology 55, 2007-2015. 

Donald  E  C,  Lawrence  J  M,  Porter  I  J  (2004).  Influence  of  particle  size  and  application 
method  on  the  efficacy  of  calcium  cyanamide  for  control  of  clubroot  of  vegetable 
brassicas Crop Protect. 23, 297-303. 

EFSA (2010a). EFSA Journal 2010; 8(11), 1873. 

EFSA (2010b). Cyanamide, Additional report, Vol 1, 04.01.2010. 

EFSA (2012). Panel on Plant Protection Products and their Residues, Guidance on Dermal 
Absorption. EFSA Journal 2012, 10(4), 2665. 

FOCUS (2014). http://focus.jrc.ec.europa.eu/. 

Gloxhuber  C  (1989).  Investigations  on  the  Absorption,  Metabolism  and  Excretion  of 
Hydrogen  cyanamide  (H2NCN)  in  rat  and  human.  SKW  Trostberg  AG,  Germany.  Study 
report 512-004. 

Güthner  T  and  Mertschenk  B  (2006).  Uhlmann’s  Encyclopaedia  of  Industrial  Chemistry, 
Wiley-VCH. 

Hartmann ROW. (2000). Patent EP 1254088. 

Haworth S, Lawlor T, Mortelmans K, Speck W, Zeiger E  (1983) Salmonella Mutagenicity 
Test Results for 250 Chemicals. Environmental Mutagenesis Supplement, 1, 3 – 142. 

Hirono Y, Nonaka K (2014), Effects of application of lime nitrogen and dicyandiamide on 
nitrous  oxide  emission  from  green  tea  fields.  Soil  Science  and  Plant  Nutrition  60,  276-
285. 

Ipser  A,  (2010a).  Calcium  cyanamide:  Carbon  Dioxide    Evolution  Test  for  Ready 
Biodegradability. Seibersdorf Labor - 332/10, September 2010, pp. 25. 

Ipser  A,  (2010b).  Calcium  cyanamide:  EpiDerm  Skin  Corrosivity  Test  (Model  EPI-200) 
Seibersdorf Labor - 195/10, June 2010, pp. 29. 

Ipser  A,  (2010c).  Calcium  cyanamide:  Bovine  Corneal  Opacity  and  Permeability  Study 
(BCOP Test Method), Seibersdorf Labor - 185/10, July 2010, pp. 27. 

Kamo  T,  Hiradate  S,  Fujii  Y  (2003).  First  Isolation  of  Natural  Cyanamide  as  a  Possible 
Allelochemical from Hairy Vetch Vicia villosa, Journal of Chemical Ecology .,  29 (2), 275-
283. 

55 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Kaushal T, Onda M, Ito S, Yamazaki A, Fujikake H, Ohtake N, Sueyoshi K, Takahashi Y, 
Nagumo Y, Tsuchida T, Ohyama T (2006). Comparison of the depth of placement of lime 
nitrogen  on  growth,  N2  fixation  activity,  seed  yield  and  quality  of  soy  bean  plants.  Soil 
Sci Plant Nutr. 52, 453-463. 

Kaushal T, Onda M, Ito S, Yamazaki A, Fujikake H, Ohtake N, Sueyoshi K, Takahashi Y, 
Ohyama  T  (2006).  Effect  of  deep  placement  of  slow-release  fertilizer  (lime  nitrogen) 
applied  at  different  rates  on  growth,  N2  fixation  and  yield  of  soya  bean.  J.  Agron.  Crop 
Sci 192, 417-426. 

Klasse  H  (1996)  Calcium  cyanamide  -  an  effective  tool  to  control  clubroot,  Acta  Hort. 
407, 403-410. 

Kotin  P  (1968).  Evaluation  of  Carcinogenic,  Teratogenic,  and  Mutagenic  Activities  of 
Selected  Pesticides  and  Industrial  Chemicals;  Volume  I  Carcinogenic  Study  National 
Cancer Institute, Division of Cancer Cause & Prevention, Carcinogenesis program. 

Kubiak  R  (1996).  Degradation  and  Leaching  Behaviour  of  PERLKA  in  Two  Loamy  Sand 
Lysimeters  Under  Outdoor  Conditions,  1996-11-18,  Registration  dossier  AlzChem 
Trostberg. 

Liggett M P (1989). Irritant effects on rabbit skin of calcium cyanamide technical grade. 
Huntingdon  Research  Centre  Ltd.,  P.O.  Box  2,  Huntingdon,  Cambridgeshire,  PE18  6ES, 
England. Study report 89558D/STB 1/SE. 

Lohman  P  H  M  (1981).  Unscheduled  DNA  synthesis  (UDS)  in  human  cells.  Medical 
Biological  Laboratory  -  TNO,  139  Lange  Kleinweg,  P.  O.  Box  45,  2280  AA  Rijswijk,  The 
Netherlands. Study report SMC 1,2. 

Maier-Greiner U H, Obermaier-Skrobranek B M, Estermaier L M, Kammerloher W, Freund 
C,  Wülfing  C,  Burkert  U  I,  Matern  D  H,  Breuer  M,  Eulitz  M  (1991).  Isolation  and 
properties  of  a  nitrile  hydratase  from  the  soil  fungus  Myrothecium  verrucaria  that  is 
highly specific for the fertilizer cyanamide and cloning of its gene. Proc Natl Acad Sci U S 
A. 88(10), 4260-4264. 

MAK  (1979).  Permanent  Senate  Commission  for  the  Investigation  of  Health  Hazards  of 
Chemical  Compounds  in  the  Work  Area  -  Maximale  Arbeitsplatzkonzentrationen  und 
Biologische Arbeitsstofftoleranzwerte, Cyanamide. 

MAK  (1997).  Permanent  Senate  Commission  for  the  Investigation  of  Health  Hazards  of 
Chemical  Compounds  in  the  Work  Area  -  Maximale  Arbeitsplatzkonzentrationen  und 
Biologische Arbeitsstofftoleranzwerte, Cyanamide. 

MAK  (2007).  Permanent  Senate  Commission  for  the  Investigation  of  Health  Hazards  of 
Chemical  Compounds  in  the  Work  Area  -  Maximale  Arbeitsplatzkonzentrationen  und 
Biologische Arbeitsstofftoleranzwerte, Cyanamide. 

MAK  (2012).  Permanent  Senate  Commission  for  the  Investigation  of  Health  Hazards  of 
Chemical  Compounds  in  the  Work  Area  -  Maximale  Arbeitsplatzkonzentrationen  und 
Biologische Arbeitsstofftoleranzwerte, Cyanamide. 

Martin  S,  Westphal  D,  Erdtmann-Vourliotis  M,  Dechet  F,  Schulze-Rosario  C,  Stauber  F, 
Wicke  H,  Chester  G  (2008).  Guidance  for  exposure  and  risk  evaluation  for  bystanders 
and residents exposed to Plant Protection Products during and after application. J. Verbr. 
Lebensm. 3, 272 – 281. 

56 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Mercier  O  (1989).  Test  to  evaluate  the  acute  ocular  irritation  and  reversibility  in  the 
rabbit.  Hazleton  France,  Les  Oncins,  B.  P.  118,  69210  L'Arbresle,  France.  Study  report 
905342. 

Mertschenk B, Bornemann W, Rust U, Schneider J-C, Wittmann H, Gloxhuber C (1991), 
Arbeitsmedizinische  Untersuchungen  an  Kollektiven 
von  Beschäftigten  einer 
Kalkstickstoffabrik, Zbl. Arbeitsmed 41, 107-119. 

Mertschenk B, Bornemann W, Pickardt C R, Rust U, Schneider J-C, Gloxhuber C (1993). 
Examinations on endocrine functions in employees from a calcium cyanamide production 
plant. Zbl. Arbeitsmed 43, 254-258. 

Nagumo Y, Tanaka K, Tewari K, Thiraporn K, Tsuchida T, Honma T, Ohtake N, Sueyoshi 
K,  Takahashi  Y,  Ohyama  T  (2009).  Rapid  quantification  of  cyanamide  by  ultra-high-
pressure 
fertilizer,  soil  or  plant  samples  Journal  of 
in 
Chromatography A, 1216, 5614–5618. 

liquid  chromatography 

NCI  (1979).  National  Cancer  Institute,  Bioassay  of  calcium  cyanamide  for  possible 
carcinogenicity. Carcinogenesis Technical Report Series No 163. 

Obach  R,  Colom  H,  Arso  J,  Peraire  C,  Prunonosa  J  (1989).  Pharmacokinetics  of 
Cyanamide in Dog and Rat. J. Pharm Pharmacol. 41, 624-627. 

Obach R, Valenti C, Valles J, Valles J M, Domenech J (1986), Bioavailability of Cyanamide 
in Fasted and Unfasted Rats, Biopharmaceutics & Drug Disposition, Vol 7, 273-280. 

Ohyama  T,  Takahashi  Y,  Nagumo  Y,  Tanaka  K,  Sueyoshi  K,  Ohtake  N,  Ishikawa  S, 
Kamiyama S, Saito M, and Tewari K (2010). Deep placement of lime nitrogen promotes 
nitrogen  fixation  and  seed  yield  of  soybean  with  efficient  utilization  rates.    19th  World 
Congress  of  Soil  Science,  Soil  Solutions  for  a  Changing  World  1  –  6  August  2010, 
Brisbane, Australia, p.32-35. 

Osheroff  M  R  (1990).  Acute  Oral  Toxicity  Study  in  Rats  with  PERLKA.  Hazleton 
Laboratories America, Inc.; 9200 Lesburg Turnpike; Vienna, Virginia 22182, USA. Study 
report 2319-136. 

Pridgen W A (1966). Toxicity studies of calcium cyanamide. Three month chronic toxicity 
study  of  calcium  cyanamide  -  thyroid  powder  combinations  in  rats.  Studies  during  life. 
Lederle  Laboratories,  Pearl  River,  New  York,  Toxicology  Research  Section, 
Pharmacological Research Department. Project number 19785. 

Rieder and Heß (1978). Modellversuch zum Abbau des herbiziden Wirkstoffs Cyanamid* 
in  drei  verschiedenen  Böden  (Title  of  the  English  translation:  Model  test  of  the 
decomposition  of  the  herbicidal  substance  cyanamide  in  three  different  soils), 
Registration dossier AlzChem Trostberg. 

Rust  U  (1987),  Conversion  rate  of  calcium  cyanamide  (technical  grade)  to  hydrogen 
cyanamide. SKW Trostberg AG, Analytical Department. Study report. 

Schiele  R,  Söll  F,  Weltle  D,  Valentin  H  (1981).  Field  study  of  workers  with  longterm 
exposure to calcium cyanamide. Zbl. Bakt. Hyg. I. Abt. Orig. B 173, 13-28. 

EPA 

Scottish 
release 
http://apps.sepa.org.uk/spripa/Pages/SubstanceInformation.aspx?pid=28 
February 2014). 

pollutant 

Scottish 

(2014). 

inventory. 
(accessed 

57 

 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Shi  K,  Wang  L,  Zhou  Y  H,  Yu  YL,,  Yu  J  Q  (2009).  Effects  of  calcium  cyanamide  on  soil 
microbial communities and Fusarium oxysporumf. sp. Cucumberinum Chemosphere, 75, 
872–877. 

Shirota  F  N,  Nagasawa  H  T,  Kwon  C  H,  Demaster  E  G  (1984).  N-Acetylcyanamide,  the 
major  urinary  metabolite  of  cyanamide  in  rat,  rabbit,  dog,  and  man.  Drug,  Metabolism 
and Disposition 12 (3), 337-344. 

Simujide  H,  Aorigele  C,  Wang  C  J,  Manda  B,  Lina  M,  Wu  MY,  Li  Y,  Bai  T  R  G  (2012). 
Reduction  of  foodborne  pathogens  during  cattle  manure  composting  with  addition  of 
calcium  cyanamide.  Journal  of  Environmental  Engineering  and  Landscape  Management, 
1–9. 

Schmidt 
14CHydrogenxyanamide, 1990-02-12, Registration dossier AlzChem Trostberg. 

(1990).  Preliminary  Study  of 

the  Aerobic  Soil  Metabolism  of 

Schmidt  (1991).  Supplemental  Report  of  the  Anaerobic  Soil  Metabolism  of  14C- 
Cyanamide, 1991-11-15, Registration dossier AlzChem Trostberg. 

Soltys  D,  Rudzinska  A,  Kurek  W,  Gniazdowska  A,  Sliwinska  E,  and  BOGATEK  R  (2011). 
Cyanamide  mode  of  action  during  inhibition  of  onion  (Allium  cepa  L.)  root  growth 
involves disturbances in cell division and cytoskeleton formation. Planta 234, 609–621. 

Terril  J  B  l  (1990).  Acute  Inhalation  Toxicity  Study  with  PERLKA  in  the  Rat.  Hazleton 
Laboratories,  Incc.  1330-B  Piccard  Drive,  Rockville  Maryland  20850-4373,  USA. 
Registration dossier AlzChem Trostberg. 

Tewari  et  al.,  (2004).  Effect  of  deep  placement  of  N  fertilisers  and  different  inoculation 
methods  of  bradyrhizobia on  growth, N-2  fixation  activity  and  N  absorption  rate of field 
grown soybean plants, Journal of Agronomy and Crop Science, 190(1), 46-58. 

Vallini G, Pera A, de Bertolde M (1983). Genotoxic Effects of Some Agricultural Pesticides 
in vitro Tested with Aspergillus nidulans. Environmental Pollution, Series A, 30, 39 – 58. 

Völkl (2000). 14C-Cyanamide Route and Rate of Degradation in Aerobic Aquatic Systems, 
2000-12-22, Registration dossier AlzChem Trostberg. 

Willems M I (1978). Evaluation of two products CCA and CA in the Salmonella/microsome 
mutagenicity  test.  TNO,  Central  Institute  for  Nutrition  and  Food  Research,  Utrechtsweg 
48, Zeist, The Netherlands. Study report 5707. 

Willems M I (1979). Evaluation of "Kalkstickstoff" and "Thioharnstoff" in the micronucleus 
test. TNO, Central Institute for Nutrition and Food Research, Utrechtsweg 48, Zeist, The 
Netherlands. Study report R 6012. 

Yamamoto A, Akiyama H, Naokawa T, Yagi K (2012). Effect of lime-nitrogen application 
on N2O emission from an Andosol vegetable field. Soil Sci Plant Nutr 58, 245–254. 

Yamamoto A, Akiyama H, Naokawa T, Miyazaki Y, Honda Y, Sano Y, Nakajima Y, Yagi K 
(2014). Lime-nitrogen application affects nitrification, denitrification, and N2O emission in 
an acidic tea soil. Biol Fertil Soils 50, 53–62. 

58 

 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

9.  ANNEXES  

Annex 1: EPISUITE results for calcium cyanamide 

Formula: 

N 

⁄⁄⁄ 
C 

⁄ 
Ca═N 

SMILES : [Ca]=NC(#N) 
CHEM : Calcium Cyanamide 
CAS NUM: 000156-62-7 
MOL FOR: C1 N2 Ca1 
MOL WT : 80.10 
------------------------------ EPI SUMMARY (v3.10) ------------------------
-- 
Physical Property Inputs: 
Water Solubility (mg/L): ------ 
Vapor Pressure (mm Hg) : ------ 
Henry LC (atm-m3/mole) : ------ 
Log Kow (octanol-water): ------ 
Boiling Point (deg C) : ------ 
Melting Point (deg C) : ------ 
Log Octanol-Water Partition Coef (SRC): 
Log Kow (KOWWIN v1.66 estimate) = -0.20 
Boiling Pt, Melting Pt, Vapor Pressure Estimations (MPBPWIN v1.40): 
Boiling Pt (deg C): 167.04 (Adapted Stein and Brown method) 
Melting Pt (deg C): -3.45 (Mean or Weighted MP) 
VP(mm Hg,25 deg C): 4.58E-019 (Modified Grain method) 
MP (exp database): 1340 deg C 
Water Solubility Estimate from Log Kow (WSKOW v1.40): 
Water Solubility at 25 deg C (mg/L): 1.934e+005 
log Kow used: -0.20 (estimated) 
no-melting pt equation used 
ECOSAR Class Program (ECOSAR v0.99g): 
Class(es) found: 
Neutral Organics 
Henrys Law Constant (25 deg C) [HENRYWIN v3.10]: 
Bond Method : Incomplete 
Group Method: Incomplete 
Henrys LC [VP/WSol estimate using EPI values]: 2.496E-025 atm-m3/mole 
Probability of Rapid Biodegradation (BIOWIN v4.00): 

59 

 
 
 
 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Linear Model : 0.7094 
Non-Linear Model : 0.8666 
Expert Survey Biodegradation Results: 
Ultimate Survey Model: 3.0222 (weeks ) 
Primary Survey Model : 3.7322 (days-weeks ) 
Readily Biodegradable Probability (MITI Model): 
Linear Model : 0.4738 
Non-Linear Model : 0.5531 
Atmospheric Oxidation (25 deg C) [AopWin v1.90]: 
Hydroxyl Radicals Reaction: 
OVERALL OH Rate Constant = 0.0000 E-12 cm3/molecule-sec 
Half-Life = ------- 
Ozone Reaction: 
No Ozone Reaction Estimation 
Soil Adsorption Coefficient (PCKOCWIN v1.66): 
Koc : 8.3 
Log Koc: 0.919 
Aqueous Base/Acid-Catalyzed Hydrolysis (25 deg C) [HYDROWIN v1.67]: 
Rate constants can NOT be estimated for this structure! 
BCF Estimate from Log Kow (BCFWIN v2.14): 
Log BCF = 0.500 (BCF = 3.162) 
log Kow used: -0.20 (estimated) 
Volatilization from Water: 
Henry LC: 2.5E-025 atm-m3/mole (calculated from VP/WS) 
Half-Life from Model River: 2.099E+021 hours (8.748E+019 days) 
Half-Life from Model Lake : 2.29E+022 hours (9.543E+020 days) 
Removal In Wastewater Treatment: 
Total removal: 1.85 percent 
Total biodegradation: 0.09 percent 
Total sludge adsorption: 1.76 percent 
Total to Air: 0.00 percent 
Level III Fugacity Model: 
Mass Amount Half-Life Emissions 
(percent) (hr) (kg/hr) 
Air 1.59e-005 1e+005 1000 
Water 45.1 360 1000 
Soil 54.9 360 1000 
Sediment 0.0755 1.44e+003 0 
Persistence Time: 421 hr 

60 

 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Annex  2:  Operator  exposure  calculations  using  UK  models  for  granular 
formulations 

Table 2.1: Operator exposure model for granular formulations, realistic worst case, small 
field, assuming 10% dermal absorption, gloves and normal work wear were worn during 
loading and application operations 

61 

EXPOSURE TO GRANULAR FORMULATIONS: VEHICLE-MOUNTED EQUIPMENTVARIABLESWork rate3ha/dayRPEApplication rate450kg a.s./haLoadingnoDermal absorption10%ApplicationInhalation absorption100%Systemic AOEL0.0043mg/kg bw/dayLOADERDermal exposurePHED surrogate - hands ADEPHED surrogate - body ADEkg a.s. loadeddermal exposureabsorbed doseInhalation exposurePHED surrogatekg a.s. loadedpotential inhalation exposuretransmission through RPE5%absorbed doseAPPLICATORDermal exposurePHED surrogate - hands ADEPHED surrogate - body ADEkg a.s. applieddermal exposureabsorbed doseInhalation exposurePHED surrogatekg a.s. appliedpotential inhalation exposuretransmission through RPE5%absorbed doseTOTAL SYSTEMICEXPOSURE AS % OF AOELmg a.s./day10%mg/kg a.s.kg a.s./day75th PERCENTILE VALUESmg/kg a.s.mg/kg a.s.kg a.s./day100%mg/kg bw/dkg a.s./daymg a.s./day10%mg/kg a.s.0.0208135028.09371.4047kg a.s./daymg a.s./daymg a.s./day100%mg/kg a.s.mg/kg a.s.0.00030.004813506.9224%0.00140.0161135023.62242.36220.69220.00101,754.5113501.34910.06750.0754 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Table 2.2: Operator exposure model for granular formulations, realistic worst case 
scenario, large field, assuming 10% dermal absorption, gloves and normal work wear 
were worn during loading and application operations 

62 

 
 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Table 2.3: Operator exposure model for granular formulations, normal case, small field, 
assuming 10% dermal absorption, gloves and normal work wear were worn during 
loading and application operations 

63 

 
 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Table 2.4: Operator exposure model for granular formulations, normal case, large field, 
assuming 10% dermal absorption, gloves and normal work wear were worn during 
loading and application operations 

64 

 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Annex 3: Exposure during private use based on puffer pack model of the UK 

Table 3.1: Exposure assessment for private use, puffer pack model assuming 10% 
dermal absorption. 

65 

PRODUCT NAMEACTIVE SUBSTANCEACTIVE CONTENTg/kgDERMAL ABSORPTION%AOELmg/kg bw/dayDERMAL EXPOSURE DURING APPLICATIONRate of exposure mg/minExposure Duration (mins)Estimated exposure to spray mg/dayHand and forearm2.8384.9Legs, feet and face2.1564.5149.410.06.723INHALATION EXPOSURE DURING APPLICATIONRate of exposure mg/minExposure Duration (mins)Estimated exposure to spray mg/dayBreathing rate = 1m3/h0.02960300.888000.3996PREDICTED EXPOSUREDERMAL (mg/day)6.723INHALATION (mg/day)0.3996TOTAL (mg/day)7.1226BODYWEIGHT (kg)600.11871THIS IS2760.7%OF THE AOEL FORTHE ESTIMATE FOR PUFFER PACK MODELPERLKACalciumcyanamide450100.004330TOTAL DERMAL EXPOSURE TO POWDER (mg/day)ABSORPTIONABSORBED DERMAL DOSE (mg/day)INHALATION EXPOSURE - 100% ABSORPTION (mg/day)OPERATOR EXPOSURE          (mg/kg bw/day)CalciumcyanamidePERLKAEXCEEDS ACCEPTABLE LEVELSAll data refer to the 75th percentile values 
 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Table 3.2: Operator exposure model for granular formulations, private use assuming 
10% dermal absorption, protective measures considered 

66 

 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Annex 4: Exposure calculation for bystander, residents and children 

Table 4.1: Operational use, exposure calculation for bystanders assuming 0.2% drift, a 
duration of 5 minutes and 10% dermal absorption. 

67 

Bystanders (adults and children)AdultsChildrenAdultsChildrenAdultsChildrenAdultsChildrenApplication rate (AS)ARmg/m24500045000450004500022500225002250022500DriftD%0.20.20.20.20.20.20.20.2Exposed Body Surface AreaBSAm210.2110.2110.2110.21Dermal absorptionDA%1010101010101010BodyweightBWkg6016.156016.156016.156016.15Specific inhalation exposureIA*mg/kg  d0.0010000.0005750.0010000.0005750.0010000.0005750.0010000.000575Area treatedA ha334848334848DurationTmin55555555Inhalation AbsorptionIA%100100100100100100100100Systemic Dermal Exposure Bystanders(ARxDxBSAxDA)/BWSDEBmg/kg bw d0.1500.1170.1500.1170.0750.0590.0750.059Systemic Inhalation Exposure Bystanders(IA*xARxAxTxIA)/BWSIEBmg/kg bw d11.25024.020180.000384.3285.62512.01090.000192.164Systemic Exposure totalmg/kg bw d11.40024.138180.150384.4455.70012.06990.075192.222syst AOELmg/kg bw d4.30E-034.30E-034.30E-034.30E-034.30E-034.30E-034.30E-034.30E-03Exposure%AOEL2.65E+055.61E+054.19E+068.94E+061.33E+052.81E+052.09E+064.47E+06realistic worst casesmall fieldlarge fieldnormal casesmall fieldlarge field 
 
 
 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Table 4.2: Operational use, exposure calculation for residents (adults and children) 
assuming 0.2% drift, a duration of 2 hours and 10% dermal absorption. 

68 

 
 
 
 
 
Potential risks to human health and the environment from the use of calcium cyanamide as fertiliser 

Table 4.3: Residential exposure, private use, uptake of granules by children 

69