Ammonium 2-amino-4-(hydroxymethylphosphinyl)butyrate

Short-term toxicity to fish

Description of key information

LC50 (96 h) = 461 mg a.s./L (mean measured) (Pimephales promelas, EPA OPPTS 850.1075) (Banman & Moore, 2013)

Additional information

For studies already evaluated for the last Annex I listing, which are considered relevant in the context of classification and labelling, summaries are taken form the DAR (2002) and its Addenda (2004). The information on new data form the Annex I renewal process relevant for the classification and labelling with regard to aquatic toxicity (Banman, C.S. & Moore, S.; 2013 and Bruns, E.; 2013) is presented within this dossier as summarised in the Document MCA for Annex I renewal.

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.

Aim of a 96-hour static test by Banman & Moore (2013) was to determine the acute toxicity of Glufosinate-ammonium Technical Concentrate (purity: 50% w/w) to the Fathead Minnow (Pimephales promelas). The study was conducted according to US EPA OCSPP 850.1075. This test resulted in the most sensitive effect value and is chosen as key study. Juvenile Fathead Minnow (mean wet weight ± SD: 0.33 ± 0.11 g; mean length ± SD: 36.5 ± 5.1 mm) were exposed under static conditions to determine the 96-hour LC50 for glufosinate-ammonium. The test was conducted at 16 hours light: 8 hours dark and 21.1 - 22.1 °C. There was a single replicate of 10 fish for the control and each treatment level. Nominal test concentrations were Control, 130, 180, 320, 560 and 1000 mg a. s. /L. Validity criteria for this study were met. Measured concentrations of glufosinate-ammonium in the test media ranged from 79% to 87% of nominal values at test initiation, and from 93% to 102% of nominal at test termination. Biological results are based on the mean measured concentrations: control, 118, 158, 279, 513, and 929 mg a. s. /L. Cumulative mortality [%] during the static exposure of Fathead minnow to glufosinate-ammonium technical concentrate are presented in the table below.

Table: Cumulative mortality [%] during the static exposure of Fathead minnow

Mean measured test concentration	4 Hour	24 Hour	48 Hour	72 Hour	96 Hour
Control	0	0	0	0	0
118 mg a. s. /L	0	0	0	0	0
158 mg a. s. /L	0	0	0	0	0
279 mg a. s. /L	0	0	0	10	10
513 mg a. s. /L	0	0	10	50	70
929 mg a. s. /L	0	70	80	90	90

Sub-lethal effects, i. e. quiescence and loss of equilibrium, could be observed at concentrations of 279 mg a. s. /L and higher. The LC50 (96 h) of glufosinate-ammonium technical concentrate to Fathead minnow (Pimephales promelas) in an acute test under static conditions was determined to be 461 mg a. s. /L (mean measured).

A limit test at 1000 (500) mg test item (pure a. s.) /L was performed by Bruns (2013) to demonstrate that fish (Cyprinus carpio) were not affected at this test item concentration. The study was conducted according to US EPA FIFRA 72-1. The mean body length of the fish was 4.6 cm, the mean body weight 1.4 g. The biomass loading for this test was 0.35 g fish / L test medium. Ten fish were exposed for 96 h under static test conditions. During the test, fish were examined after four hours and then daily for mortalities and signs of poisoning. Within the study the pH-value, the oxygen saturation level and the temperature were measured with commercial measurement devices, daily. Dissolved oxygen concentrations ranged from 89 to 102% oxygen saturation, the pH values ranged from 6.6 to 7.1 and the water temperature ranged from 21.0 °C to 22.2 °C in all aquaria over the whole testing period. The analytical determination of glufosinate-ammonium (in water by HPLC – MS/MS) revealed measured concentrations ranging from 92% to 106% of nominal concentration. The analytical findings confirm the nominal concentration. Therefore, the results of this study are presented based on nominal concentrations. There were neither any sub-lethal effects nor any mortality observed in the control group. No mortality or sublethal effects were observed. Test conditions met all validity criteria. The 96h-LC50 is greater than 1000 (500) mg test item (pure a. s.) / L.

The acute toxicity of glufosinate-ammonium (AE F039866 technical ;GA, purity 97%) to fish was investigated in three static studies (McAllister (1985a, 1985b), Swigert (1986)) generally in accordance with OECD Guidelines 203. The test species were Oncorhynchus mykiss, Lepomis macrochirus and Cyprinodon variegatus. Test concentrations were 100, 180, 320, 560, and 1,000 mg/L (nominal) plus control. Ten fish were exposed to each test concentration and control. The test conditions and results are summarised in the following table (results are based on nominal test concentrations).

Table: Summary of test conditions and results of the acute toxicity to fish

Species	Body size	Temperature	pH	96 hours LC50	96 hours NOEC
	(mm)	(°C)		(mg a.s./L)	(mg a.s./L)
O. mykiss	30 + 1	11	7.2 – 7.6	710	320
L. macrochirus	18 + 1.5	22	7.0 – 7.6	>1000	180
C. variegatus	25 + 2.6	24	7.5 – 7.9	>1000	>=1000

Sublethal effects as loss of equilibrium, quiscence, surfacing lying at the bottom and discoloration were observed on O. mykiss and L. macrochirus. On the marine species C. variegatus, no signs of dose related sublethal effects were seen during the study. No analytical measurements for the test substance were performed during the tests, and the results were based on nominal test concentrations. The conclusion of the former RMS Sweden was, “However, since glufosinate-ammonium is readily soluble in water, stable towards abiotic degradation and not expected to volatilise, the studies are considered valid.”

The acute toxicity of technical grade glufosinate-ammonium (Hoe 039866, purity 96.3%) to Leuciscus idus melanotus (Golden Orfe) was tested under static conditions in accordance with DIN-Guideline 38412-L15, (1982) and GLP (Fischer, 1987a). The test was conducted in 18 L fish tanks maintained at 20.1 ± 0.61 °C in a temperature controlled area; pH values ranged from 7.0 to 7.6; dissolved oxygen content was 5.3 - 9.8 mg/L. Nominal test concentrations were 0, 320, 560 and 1000 mg/L. One replicate with ten fish (age of approx. 13 months) was used for each test concentration, with a biological loading of 2.0 mg/L. Mortality and behavioral responses were recorded every 24 hours during the test. The 96 hours LC50 for Leuciscs idus melanotus was determined to be >1000 mg/L, the NOEC was >= 1000 mg/L.