AMMONIUM SULFATE CAS N°: 7783-20-2

OECD SIDS
AMMONIUM SULFATE
freshwater snail Helisoma trivolyis (Tchounwou, Englande and Malek, 1991). Some other results
(e.g. Daphnia) are > 100 mg/l. For the algal species Chlorella vulgaris (Tam and Wong, 1996) an
EC 50 (18d, cell count) of ca. 2700 mg/l can be calculated.
In aquatic freshwater systems, chronic toxicity information is available for fish, the trophic level
shown to be the most sensitive in acute tests. The greatest sensitivity to ammonium sulfate was
shown by alevins of Oncorhynchus gorbuscha before complete yolk absorption, with a NOEC
(61 d) of 11 mg/l (NH 4 ) 2 SO 4 for effects on the length and weight of fry at emergence (Rice and
Bailey, 1980). In a single concentration study at 100 mg/l, utilizing a commercial fertilizer of
unspecified composition at almost an order of magnitude higher ammonium sulfate levels for 6
months, effects were seen on ovarian, testicular, and pituitary systems in the catfish Channa
punctatus (Ram and Sathyanesan, 1986, 1987).
Marine Environment
A limited amount of ammonium sulfate toxicity data is also available for the marine environment.
For acute tests the lowest LC 50 (10 d) observed for fish is 27 mg/l ammonium sulfate for one or two
day post hatch larvae of the warm water marine species Sciaenops ocellatus (Holt and Arnold,
1983). An invertebrate LC 50 (96 h) of 47.7 mg/l is observed for young green mussels (Perna
viridis), also a warm water marine species (Reddy and Menon, 1979). However, the highest toxicity
in marine systems is shown by phytoplankton. The NOEC (17 d, growth inhibition) is 0.471 mg/l
ammonium sulfate for the marine dinoflagellates Gymnosium splendens and Gonyaulax polyedra
(Thomas, Hastings and Fujita, 1980).
Toxicity to Microorganisms
Ammonium sulfate toxicity information is available for both sewage treatment microorganisms and
for microorganisms found in soil. The sewage treatment study (Suwa et al., 1994) investigated 14
strains of Nitrobacter spp. (ammonium oxidising bacteria) isolated from 25 different sludges
including three sludges from primary sewage treatment plants and two sludges from nightsoil
treatment plants. Nitrite production kinetic studies showed that insensitive strains (those which
grew well at 4700 mg/l ammonium sulfate) showed Monod growth, while sensitive strains (those
which grew at 94 mg/l but not at 4700 mg/l) followed Haldane kinetics. The results suggested that
ammonium sulfate sensitive strains had a growth advantage in lower ammonium sulfate
concentrations, while insensitive strains had a growth advantage at higher ammonium sulfate
concentrations. Both sensitive and insensitive strains were found in the primary and nightsoil
sludges, with the sensitive strains predominating. This explained the operational observations in
several sewage treatment plants concerning the efficacy of nitrifying bacteria.
Studies of the effects of ammonium sulfate on three nitrogen-fixing soil bacteria and on total soil
bacteria have also been carried out. The abundance of nitrogen-fixing cyanobacteria in a Spanish
rice field was reduced significantly following a single ammonium sulfate application even at the
lowest application of 82.5 kg/ha (calculated from 17.5 kg N/ha) (Fernández Valiente et al., 2000).
In another experiment, biological nitrogen-fixing ability in a field under crop rotation in southern
Sweden was reduced (nitrogen-fixing legume bacteria) or eliminated (nitrogen-fixing blue green
algae) by over thirty years annual application of 377 kg/ha ammonium sulfate (calculated from
80 kg N/ha) (Martensson and Witter, 1990). The lowering of soil pH by ammonium sulfate was the
main cause of the reduction in the nitrogen-fixing capacity of the soil. In this experimental field,
total soil biomass was reduced by almost 50 % relative to unfertilized control plots (Witter,
Martensson and Garcia, 1993), although base respiration rate was unaffected.
UNEP PUBLICATIONS 33