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Appendix 5; Eco-toxicity of Nitroguanidine (Picrite) and its Degradation Products 1.0 Background
Nitroguanidine is a constituent of some gun propellants. This substance was
manufactured at the now decommissioned Royal Ordnance Factory, Bishopton.
Relatively high concentrations of this substance have been discovered previously in
the effluent disposal lagoons situated approximately 1km southwest from the main
site. These lagoons were used until 1993 for the disposal of lime neutralised
sulphuric acid effluent, a by-product of picrite manufacture. The slurry was pumped
to the lagoons, the solids allowed to settle out and the supernatant left to drain away
from the unlined lagoons and/or evaporate to the atmosphere. Periodically, when the
material had dried sufficiently, solids were excavated and mounded on adjacent land
Analysis of samples from the lagoons suggests that the lagoon solids are rich in
calcium and sulphate1. The concentration (%w/w) of Ca in the samples was
approximately 20.3±5%, whilst the concentration of SO 2-
This raises t2he possibility of the formation of a range of calcium sulphate like
minerals in varying mass ratios of calcium and sulphate. The pH of the lagoon solids
was in the range 4.1-12.7, with a decrease in value as the depth of the lagoons
increased. The average total nitroguanidine concentration in the lagoon samples
was in the range <0.05 – 1320 mg L-1. The average leachable nitroguanidine
concentration in water samples collected at varying lagoon depths was in the range
The effluent discharge lagoons at the former Royal Ordnance Factory, Bishopton
known as the ‘picrite lagoons’ contain traces of nitroguanidine (picrite). Picrite has
also been detected over the years in groundwater and surface water at up to 32mg/l.
However, concentrations have decreased significantly since the factory ceased
production in 2002 and decommissioning of the section took place. Surface water
samples have recorded less than 5mg/l picrite since January 2004 and the majority
of groundwaters were found to contain less than 1mg/l picrite, except from one
borehole where a maximum of 12mg/l has been detected.
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Ecological Toxicity of Nitroguanidine Invertebrates
Van der Schalie3 has studied the acute toxicity of nitroguanidine to several
invertebrates. No 48 hour LD50 were obtained by van der Schalie3 for the following
invertebrates exposed to saturated solutions of nitroguanidine: water flea (P. magna)
at 2838mg L-1, amphipods Gammarus minus and Hyallela azteca at 2720 and
2730mg L-1 respectively; midge larva (P. dissimilis) at 3395 mg L-1 and aquatic
oligochaete (L. variegates) at 2868mg L-1. Warner (1978) found that nitroguanidine
was not acutely toxic to D. magna (20°C) at a nominal concentration of 1175 mg L-1.
Fish
Various studies have shown that no mortality occurred to the rainbow trout or fathead
minnow in 96h at the solubility limits of the compound, which were 1550mg L-1 for
rainbow trout at 12°C and 3320mg L-1 for fathead minnow at 25°C. In a study
conducted by Burton et al (1993)4 it was observed that there was no mortality to 17d
old rainbow trout exposed to 1550mg L-1 nitroguanidine at 25°C. Similarly there was
no mortality to 37d old fathead minnow exposed to 1550mg L-1 at 12°C or in the van
der Schalie3 study (63d old; 22°C) at 2634 mg L-1. Therefore, it can be concluded
that the acute toxicity of nitroguanidine to freshwater invertebrates and fish is quite
low. With the exception of the hydra and cladoceran in which the 48h LD50s were
2061 and 2698mg L-1 respectively, the toxicity of nitriguanidine does not appear to be
an acute hazard to freshwater invertebrates and fish except at concentrations
approaching the solubility limit of the compound in water.
Toxicity of Photolyzed Nitrogaunidine
Several authors have reported that photolyzed nitroguanidine was approximately two
orders of magnitude more toxic to the cladoceran than the parent compound under
the same test conditions. Van der Schalie (1985)3 exposed green algae (S. capricornutum), water flea (D. magna), and fathead minnow to photolyzed
nitroguanidine and found it to be more toxic. The 120h LD50 concentration of the
parent compound was 2146mg L-1 whilst the 120h LD50 concentration of the
photolyzed compound was 32mg L-1 for the algae exposed to these compounds.
The 48h and 96h LD50s of the water flea and fathead minnow were >2838mg L-1 and
>2714mg L-1 respectively, when the organisms were exposed to the parent
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compound. The 48h and 96h LD50s of the water flea and fathead minnow exposed to
photolyzed nitroguanidine were 25mg L-1 and 35mg L-1 of the compound respectively.
A number of products are formed in aqueous solution when nitroguanidine is
photolyzed in distilled water or surface waters by UV radiation or natural light.
Studies of the UV photolysis of nitroguanidine in unbuffered distilled water have
shown that the products are primarily guanidine, urea, and nitrite, with lesser
quantities of cyanoguanidine, ammonia, and nitrate5,6. Nitrosoguanidine has been
observed as a transient intermediate which appears to be photolyzed to guanidinium
nitrate7. Several of the above products have also been observed in surface waters
photolyzed by sunlight although the yields were different in most cases.
Burrows et al (1988)6 conducted a literature survey of the toxicity of photolyzed
nitroguanidine products to aquatic organisms. They concluded that of the five
photolysis products for which data were available, four are more toxic to aquatic
organisms than the parent compound. They pointed out, however, that only nitrite
ion is present at a concentration high enough to account for the greatly enhanced
toxicity of photolyzed nitroguanidine observed in the Van der Schalie (1985)3 study.
Burrows et al. (1988)6 also made the point that synergistic effects may be involved in
the observed toxicity. The cladoceran in the current study was approximately an
order of magnitude more sensitive to photolyzed nitroguanidine than the organisms in
the Van der Schalie study. Similar data on the chronic toxicity of the photolyzed
products to the cladoceran are not available. Clearly, one or more of the photolyzed
products is quite toxic to the cladoceran.
The environmental fate of nitroguanidine in surface waters has been shown to be
dominated by photolysis. The half life of nitroguanidine at 40°N latitude ranges from
0.6 days in summer to 2.3 days in winter. Although nitroguanidine is very soluble in
water, it is not toxic to several aquatic organisms at its solubility limit. However,
photolyzed nitroguanidine is about two orders of magnitude more toxic than the
parent compound. It is clear that photolysis should be considered during hazard
evaluation of nitroguanidine discharged to the aquatic environment.
Toxicity of Chemical and Biodegraded Nitroguanidine
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Kaplan et al. (1982)8 and Haag et al. (1990)9 have evaluated the susceptibility of
nitroguanidine to microbial degradation and the potential hazards associated with the
degradation products. They observed that nitroguanidine did not biodegrade until the
anaerobic cultures had a sufficient period of acclimatisation. Once acclimated,
anaerobic cultures readily reduced nitroguanidine cometabolically. This
transformation did not occur under aerobic conditions. No evidence was found for
further microbiological reduction of nitrosoguanidine. Unlike nitroguanidine, Kaplan
et al (1982) were unable to acclimatise cells to completely metabolise
nitrosoguanidine by further reduction. Probable reduction products would have been
hydrazine and urea or aminoguanidine and guanidine. Hydrazine, urea and
aminoguanidine were never detected during these studies, and guanidine, although
present in trace amounts, can be postulated to arise by an alternative pathway.
Figure 1: Scheme for chemical and biological degradation of nitroguanidine. Step 1 is biologically mediated; step 2 and beyond are chemically mediated (Kaplan et al., 1982). It is probable that under these conditions nitrosoguanidine decomposes
nonbiologically. Significant quantities of cyanamide, cyanoguanidine and melamine
were identified in the culture effluents. These products were reported to be among
the products of the chemical decomposition of nitrosoguanidine (Figure 1).
Nitrosoguanidine decomposes to cyanamide and nitrosamide. The cyanamide
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polymerises to its dimer, cyanoguanidine, and finally to its trimer, cyclic melamine.
Cyanamide can also react with ammonia to form guanidine. The nitrosamide formed
is transitory and decomposes to nitrogen gas and water.
Kaplan et al., (1982) observed that in sterile broth batch culture controls, under
anaerobic conditions with a reducing agent present, there was no change in the
concentration of nitroguanidine, and there was no evidence for nonbiological
reduction to nitrosoguanidine. Sterile broth controls with nitrosoguanidine revealed
similar patterns of substrate disappearance and product formation, supporting the
notion that the decomposition steps from nitrosoguanidine are nonbiologically
mediated. Under more harsh chemical conditions, Davis and Rosenquist (1937)10
reported that nitrosoguanidine reacts chemically with ammonia to give cyanamide
and nitrosamide. With excess ammonia this reaction proceeds to guanidine,
melamine, ammeline, ammelide and a trace of urea. Presumably, under the milder
conditions of biological studies, the hydroxylated analogues of melamine are not
Nitrosoguanidine and nitroguanidine gave negative results in the Ames screening
test for mutagenicity. Nitrosoguanidine, however, was reported to be a carcinogen in
screening tests with Chinese hamster cells for detection of chromosomal
aberrations11. Cyanamide is metabolised by plants to arginine through various
guanidino compounds12. Calcium cyanamide is used as a plant fertiliser13 and root
stimulator and is not carcinogenic14. Cyanamide is bacteriostatic at 1000mg L-1 and
toxic to mammals. Melamine presents a low toxicity hazard.
Aquatic Fate of Nitroguanidine
The high water solubility and the low values of the Henry’s constant, soil sorption
coefficient, and biouptake coefficient all indicate that nitroguanidine exists
predominantly in the aqueous phase of the environment9. In oligotrophic streams
and lakes, the fate of nitroguanidine will be dominated by photolysis, with surface
half-lives at 40°N ranging from 0.6d in summer to 2.3d in winter. Photolysis products
include nitrite, nitrate, hydroxyguanidine and unknown products of hydroxyguanidine
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In coloured, eutrophic surface waters, photolysis will be inhibited and
biotransformation promoted, resulting in photolysis half-lives of several days and
biotransformation half-lives as short as one day. Cyanamide was the only significant
biotransformation product observed. In ground waters, anaerobic biotransformation
is expected to be the dominant fate process, having a half-life of 4 days. Abiotic,
sediment mediated reduction is a possibly important process that has not yet been
investigated. Similar environmental fate parameters are found for water-soluble nitro
compounds such as diethylene glycol dintrate.
1.6 Conclusions
The effluent discharge lagoons at the former Royal Ordnance Factory, Bishopton
known as the ‘picrite lagoons’ contain traces of nitroguanidine (picrite). Picrite has
also been detected over the years in groundwater and surface water at up to 32mg/l.
However, concentrations have decreased significantly since the factory ceased
production in 2002 and decommissioning of the section took place. Surface water
samples have recorded less than 5mg/l picrite since January 2004 and the majority
of groundwaters were found to contain less than 1mg/l picrite, except from one
borehole where a maximum of 12mg/l has been detected.
Picrite on its own is a non-toxic substance with a toxicity threshold as high as
2200mg L-1. Various authors have experimentally shown that although picrite is a
non-toxic substance, in the presence of light and/or microorganisms it degrades to
nitrosoguanidine, guandine, cyanoguanidine, melamine, urea and ammonia. Each of
these degradation products has varying degrees of toxicity, with the overall toxicity of
nitroguanidine being approximately two orders of magnitude more when compared
with the toxicity of the parent compound. The threshold toxicity level of photolyzed
nitroguanidine is approximately 32mg L-1.
Published literature to date suggests that nitroguanidine cannot be successfully
metabolised by microbial activity to completely innocuous compounds.
Nitrosoguanidine, a nitrosamine, is the primary reduction product, and no evidence
was found for further microbial action on this compound. Residual levels of
nitrosoguanidine persist because of the slow rates of chemical reaction under
biological conditions. More stringent chemical conditions would presumably enhance
the rate of decomposition and change the number and the types products found in
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It is therefore recommended that the threshold toxicity level of phytolyzed
nitroguanidine of 32mg/l is used as the Tier 1 assessment criteria for assessing the
REFERENCES
1 BAE SYSTEMS Environmental Services (2003). Preliminary Ground Investigation: Picrite
Lagoons, RO Bishopton. Prepared for BAE SYSTEMS Properties Ltd. BAE SYSTEMS,
Westcott Venture Park, Westcott, Aylesbury, UK.
2 BAE Systems Environmental (2006). Generic Quanititative Risk Assessment Report, Bishopton A385-00-R5-A. 3 Van der Schalie, W.H. (1985). The toxicity of nitroguanidine and photolyzed nitroguanidine
to freshwater aquatic organisms. Technical Report 8404, AD A153045. U.S. Army Medical
Bioengineering Research and Development Laboratory, Fort Detrick, Fredrick, MD.
4 Burton, D. T., Turley, S. D., Peters, G. T. (1993). Toxicity of nitroguanidine, nitroglycerin,
hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and 2,4,6-trinitrotoluene (TNT) to selected
freshwater aquatic organisms. US Army Medical Research and Development Command, Fort
5 Noss, C. I and Chyrek, R. H. (1984). Nitroguanidine wastewater pollution control
technology: Phase III. Treatment with ultraviolet radiation, ozone and hydrogen peroxide.
Technical Report 8309, AD A139389. U.S. Army Medical Bioengineering Research and
Development Laboratory, Fort Detrick, Frederick, MD.
6 Burrows, W. D., Schmidt, M.O, Chyrek, R. H. and Noss, C.I. (1988). Photochemistry of
aqueous nitroguanidine. Technical Report 8803, AD A203200. U.S. Army Medical Research
and Development Laboratory, Ft. Detrick, Detrick, Fredrick, MD.
7 Burrows, E.P., Rosenblatt, D.H., Mitchell, W. R., and Parmer, D. L. (1989). Organic
explosives and related compounds: Environmental and health considerations. Technical
Report 8901, AD A210554. U.S. Army Biomedical Research and Development Laboratory,
8 Kaplan, D. L., Cornell, J.H. and Kaplan, A. M. (1982). Decomposition of Nitroguanidine.
Generic Quantitative Risk Assessment Report, Bishopton
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9 Haag, W. R., Spanggord, R., Mill, T. (1990). Aquatic environmental fate of nitroguanidine.
10 Davis, T. L., Rosenquist, E.N. (1937). J. Am. Chem. Soc. 15, 2112-2115.
11 Ishidate, M., Odashima, S. (1977). S. Mut. Res., 48, 337-354.
12 Wvensch, A., Amberger, A.A. (1974). Z. Pfalzenphysiol. 72, 359-366.
13 Iwasaki, K., Weaver, R. J. (1977). J. Am. Soc. Hort. Sci. 102, 584-587.
14 Sax, M. I. (1975). Dangerous Properties of Industrial Materials. Van Nostrand Reinhold,
Infertility and IVF The IVF Unit at Sophiahemmet The IVF Unit was established in 1984. We can offer most types of treatment for infertility. IVF (in vitrofertilization) constitutes a large part of our work. Staff: Physicians: Arthur Aanesen, MD, PhD Claes Gottlieb, Associate Professor ___________________________________________________________________________ Visiting ad
Procedural pragmatics and the study of discourse The term discourse is generally used either as a technical equivalent for ‘verbal communication’ or as referring to a particular scientific notion, where discourses are spans of texts or of utterances obeying specific principles of organisation. The aim of this paper is to suggest that an account of discourse is possible, in both cases, on
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Appendix 5; Eco-toxicity of Nitroguanidine (Picrite) and its Degradation 
Generic Quantitative Risk Assessment Report, Bishopton
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Ecological Toxicity of Nitroguanidine 
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compound. The 48h and 96h LD50s of the water flea and fathead minnow exposed to
photolyzed nitroguanidine were 25mg L-1 and 35mg L-1 of the compound respectively.
A number of products are formed in aqueous solution when nitroguanidine is
photolyzed in distilled water or surface waters by UV radiation or natural light.
Studies of the UV photolysis of nitroguanidine in unbuffered distilled water have
shown that the products are primarily guanidine, urea, and nitrite, with lesser
quantities of cyanoguanidine, ammonia, and nitrate5,6. Nitrosoguanidine has been
observed as a transient intermediate which appears to be photolyzed to guanidinium
nitrate7. Several of the above products have also been observed in surface waters
photolyzed by sunlight although the yields were different in most cases.
Burrows et al (1988)6 conducted a literature survey of the toxicity of photolyzed
nitroguanidine products to aquatic organisms. They concluded that of the five
photolysis products for which data were available, four are more toxic to aquatic
organisms than the parent compound. They pointed out, however, that only nitrite
ion is present at a concentration high enough to account for the greatly enhanced
toxicity of photolyzed nitroguanidine observed in the Van der Schalie (1985)3 study.
Burrows et al. (1988)6 also made the point that synergistic effects may be involved in
the observed toxicity. The cladoceran in the current study was approximately an
order of magnitude more sensitive to photolyzed nitroguanidine than the organisms in
the Van der Schalie study. Similar data on the chronic toxicity of the photolyzed
products to the cladoceran are not available. Clearly, one or more of the photolyzed
products is quite toxic to the cladoceran.
The environmental fate of nitroguanidine in surface waters has been shown to be
dominated by photolysis. The half life of nitroguanidine at 40°N latitude ranges from
0.6 days in summer to 2.3 days in winter. Although nitroguanidine is very soluble in
water, it is not toxic to several aquatic organisms at its solubility limit. However,
photolyzed nitroguanidine is about two orders of magnitude more toxic than the
parent compound. It is clear that photolysis should be considered during hazard
evaluation of nitroguanidine discharged to the aquatic environment.
Toxicity of Chemical and Biodegraded Nitroguanidine 
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Kaplan et al. (1982)8 and Haag et al. (1990)9 have evaluated the susceptibility of
nitroguanidine to microbial degradation and the potential hazards associated with the
degradation products. They observed that nitroguanidine did not biodegrade until the
anaerobic cultures had a sufficient period of acclimatisation. Once acclimated,
anaerobic cultures readily reduced nitroguanidine cometabolically. This
transformation did not occur under aerobic conditions. No evidence was found for
further microbiological reduction of nitrosoguanidine. Unlike nitroguanidine, Kaplan
et al (1982) were unable to acclimatise cells to completely metabolise
nitrosoguanidine by further reduction. Probable reduction products would have been
hydrazine and urea or aminoguanidine and guanidine. Hydrazine, urea and
aminoguanidine were never detected during these studies, and guanidine, although
present in trace amounts, can be postulated to arise by an alternative pathway.
Figure 1: Scheme for chemical and biological degradation of nitroguanidine. 
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polymerises to its dimer, cyanoguanidine, and finally to its trimer, cyclic melamine.
Cyanamide can also react with ammonia to form guanidine. The nitrosamide formed
is transitory and decomposes to nitrogen gas and water.
Kaplan et al., (1982) observed that in sterile broth batch culture controls, under
anaerobic conditions with a reducing agent present, there was no change in the
concentration of nitroguanidine, and there was no evidence for nonbiological
reduction to nitrosoguanidine. Sterile broth controls with nitrosoguanidine revealed
similar patterns of substrate disappearance and product formation, supporting the
notion that the decomposition steps from nitrosoguanidine are nonbiologically
mediated. Under more harsh chemical conditions, Davis and Rosenquist (1937)10
reported that nitrosoguanidine reacts chemically with ammonia to give cyanamide
and nitrosamide. With excess ammonia this reaction proceeds to guanidine,
melamine, ammeline, ammelide and a trace of urea. Presumably, under the milder
conditions of biological studies, the hydroxylated analogues of melamine are not
Nitrosoguanidine and nitroguanidine gave negative results in the Ames screening
test for mutagenicity. Nitrosoguanidine, however, was reported to be a carcinogen in
screening tests with Chinese hamster cells for detection of chromosomal
aberrations11. Cyanamide is metabolised by plants to arginine through various
guanidino compounds12. Calcium cyanamide is used as a plant fertiliser13 and root
stimulator and is not carcinogenic14. Cyanamide is bacteriostatic at 1000mg L-1 and
toxic to mammals. Melamine presents a low toxicity hazard.
Aquatic Fate of Nitroguanidine 
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In coloured, eutrophic surface waters, photolysis will be inhibited and
biotransformation promoted, resulting in photolysis half-lives of several days and
biotransformation half-lives as short as one day. Cyanamide was the only significant
biotransformation product observed. In ground waters, anaerobic biotransformation
is expected to be the dominant fate process, having a half-life of 4 days. Abiotic,
sediment mediated reduction is a possibly important process that has not yet been
investigated. Similar environmental fate parameters are found for water-soluble nitro
compounds such as diethylene glycol dintrate.
1.6 Conclusions 
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It is therefore recommended that the threshold toxicity level of phytolyzed
nitroguanidine of 32mg/l is used as the Tier 1 assessment criteria for assessing the
Generic Quantitative Risk Assessment Report, Bishopton
Redrow Group & BAE Systems Property Investments Ltd.
9 Haag, W. R., Spanggord, R., Mill, T. (1990). Aquatic environmental fate of nitroguanidine.
10 Davis, T. L., Rosenquist, E.N. (1937). J. Am. Chem. Soc. 15, 2112-2115.
11 Ishidate, M., Odashima, S. (1977). S. Mut. Res., 48, 337-354.
12 Wvensch, A., Amberger, A.A. (1974). Z. Pfalzenphysiol. 72, 359-366.
13 Iwasaki, K., Weaver, R. J. (1977). J. Am. Soc. Hort. Sci. 102, 584-587.
14 Sax, M. I. (1975). Dangerous Properties of Industrial Materials. Van Nostrand Reinhold,