Ammonium 2-amino-4-(hydroxymethylphosphinyl)butyrate

Endpoint summary

Additional information

Laboratory studies on the effects of glufosinate-ammonium on aquatic organisms (fish, invertebrates, algae, higher plants) are summarised in the table below. In the subsequent sections executive summaries of the available studies on glufosinate-ammonium are provided in more detail.

Key values (bold) were taken into account for the assessment of environmental classification and as key endpoints of glufosinate-ammonium.

Test organism	study type	Test duration	LC50/EC50 (mg as/L)	NOEC (mg as/L)	Author
Acute toxicity to fish
Pimephales promelas (fathead minnow)	static acute	96 hours	461	158	Banman & Moore 2013; M-468603-01-1
Cyprinus carpio (carp)	static acute	96 hours	>500	≥500	Bruns 2013; M-450082-01-1
Oncorhynchus mykiss (rainbow trout)	static acute	96 hours	710	320	McAllister 1985a; M-110629-01-1
Lepomis macrochirus (bluegill sunfish)	static acute	96 hours	>1000	180	McAllister 1985b; M-110633-01-1
Cyprinodon variegatus (sheepshead minnow)	static acute	96 hours	>1000	≥1000	Swigert 1986; M-113646-01-1
Leuciscus idus melanotus (golden orfe)	Static acute	96 hours	>1000	≥1000	Fisher 1987a; M-117920-01-2
Chronic toxicity to fish
Pimephales promelas (fathead minnow)	early life stage, flow-through	35 days	-	26.2	Banman et al. 2014; M-507827-01-1
Oncorhynchus mykiss (rainbow trout)	growth test, flow-through	21 days	224	100	Fischer 1989; M-123788-01-1
Acute toxicity to aquatic invertebrates
Daphnia magna (waterflea)	static acute	48 hours	>100	≥100	Ruhland 2009a; M-344395-01-1
Daphnia magna (waterflea)	static acute	48 hours	>1000	560	Forbis 1985; M-110636-01-1
Americamysis bahia (mysid shrimp)	static acute	96 hours	7.5	≥1	Forbis 1986; M-113650-01-1
Daphnia magna (waterflea)	static acute	48 hours	668	420	Fischer 1982; M-096871-01-1
Chronic toxicity to aquatic invertebrates
Daphnia magna (waterflea)	semi-static	21 days	-	18	Fischer 1987b; M-118006-01-1
Effects on algal growth
Anabaena flos-aquae (blue-green alga)	static, growth inhibition	96 hours	ErC50 (72 h): 0.132	NOECr (72 h): 0.039	Banman et al. 2011a; M-404352-01-1
Skeletonema costatum (diatom)	static, growth inhibition	96 hours	ErC50 (72 h): 52.4	NOECr (72 h): 12.5	Banman et al. 2011b; M-404356-01-1
Pseudokirchneriella subcapitata (green alga)	static, growth inhibition	72 hours	ErC50 (72 h): 46.4	NOECr (72 h): <6.25	Ruhland 2009b; M-333684-01-1
Pseudokirchneriella subcapitata (green alga)	static, growth inhibition	7 days	ErC50: 37.3	2.5	Hughes 1987; M-117501-01-1
Scenedesmus subspicatus (green alga)	static, growth inhibition	72 hours	ErC50: >1000	100	Heusel 1994; M-133145-01-1
Navicula pelliculosa (diatom)	static, growth inhibition	120 hours	ErC50: >100	100	Sowig & Gosch 2001; M-201068-01-1
Effects on higher aquatic plants
Lemna gibba (duckweed)	Semi-static, frond number and growth rate	14 days	EC50: 1.5	0.8	Lintott & Ward 1991; M-130939-01-1

Six studies on the acute toxicity of glufosinate-ammonium to fish are available. All studies were conducted according to GLP and different international guidelines. Fife species of freshwater fish (Pimephales promelas, Cyprinus carpio, Oncorhynchus mykiss, Lepomis macrochirus, Leuciscus idus melanotus) and one saltwater species (Cyprinodon variegatus) were tested. The 96-hour static test by Banman & Moore (2013) using fathead minnow (Pimephales promelas) resulted in the most sensitive effect value, i.e. LC50 (96 h) = 461 mg a.s./L (mean measured), and is chosen as key study.

Two studies on the chronic toxicity of glufosinate-ammonium to fish are available. Both studies were conducted according to GLP and different international guidelines. Two species of freshwater fish (Pimephales promelas, Oncorhynchus mykiss) were tested. The 35 days to early life stage study under flow-through conditions by Banman et al. (2014) using fathead minnow (Pimephales promelas) resulted in the most sensitive effect value, i.e. NOEC (35 d) = 26.2 mg a.s./L (mean measured) and is chosen as key study.

Four studies on the acute toxicity of glufosinate-ammonium to aquatic invertebrates are available. All but one study were conducted according to GLP and different international guidelines. One freshwater species (Daphnia magna) and one saltwater species (Americamysis bahia) were tested. Information on saltwater species are not considered relevant for classification and labelling. The study conducted by Ruhland (2009a) according to standard methods using Daphnia magna yielded the lowest relevant endpoint for the standard species Daphnia magna (EC50 (48 h)> 100 mg a.s./L) and was chosen as key.

The chronic toxicity of glufosinate-ammonium was tested on Daphnia magna over 21 days in a semi-static test design (Fischer, 1987b). The study was conducted according to GLP and an international guideline. The 21 days NOEC could be determined to 18 mg/L based on mortality.

Six studies on the toxicity of glufosinate-ammonium to algae are available. All studies but one were conducted according to GLP and different international guidelines. Five species of freshwater algae (Anabaena flos-aquae (blue-green alga), Skeletonema costatum, Pseudokirchneriella subcapitata, Scenedesmus subspicatus, Navicula pelliculosa (diatom)) were tested. The new study by Banman et al. (2011a) using the blue-green alga Anabaena flos-aquae during a 96-hour static exposure regime resulted in the most sensitive effects values. The 72-hour EC50 value for growth rate (ErC50) was determined to be 132 µg a.s./L with a NOEC of 39 µg a.s./L, based on nominal concentrations.

A 14-day static growth test to the freshwater duckweed, Lemna gibba, was conducted by Lintott & Ward (1991). The test was conducted under static conditions. Frond numbers were determined. EC50 based on frond number after 14 days was determined to be 1.5 mg/L and the NOEC was 0.8 mg/L (mean measured).

 

In conclusion the most sensitive key values from the aquatic toxicity studies conducted and used for environmental classification & labelling are the effect values from the study with the blue-green algae Anabaena flos-aquae, i.e. an ErC50 (72 h) of 0.132 mg a.s./L and a NOEC (72 h) of 0.039 mg a.s./L.