Butylamine

Endpoint summary

Description of key information

Fish

LC50 (96 h, freshwater) = 32 mg/L

LC50 (96 h, marine water) = 24 mg/L

Aquatic invertebrates

EC50 (48 h) = 8.2 mg/L (geometric mean of EC0 and EC100; mean measured)

NOEC (7 -d, reprod.) = 1.09 mg/L (TWM measured)

Algae

ErC50 (72 h) = 17 mg/L (geometric mean measured)

ErC10 (72 h) = 3.7 mg/L (geometric mean measured)

Microorganisms

NOEC (Pseudomonas putida; 16 h) = 800 mg/L (buffered)

Additional information

Summary of aquatic toxicity

Fish

LC50 (96 h, freshwater) = 32 mg/L

LC50 (96 h, marine water) = 24 mg/L

The acute LC50 values for fresh water fish range between 32 and 268 mg/L (Dawson et al., 1975 and Geiger et al., 1985, respectively). They were obtained under non-neutralised (Dawson) and neutralized (Geiger) conditions, such that basicity is concluded to contribute to toxicity considerably.

Dawson et al. (1975) studied in addition toxicity to salt water / marine water fish. The tested salt water species was Tidewater Silverside (Menidia beryllina), and a LC50 (96 h) of 24 mg/L was determined.

The acute toxicity values relevant for classification are located between 10 and 100 mg/L. The result obtained on marine fish (LC50 = 24 mg/L) corresponds to that found with freshwater fish [Dawson et al. 1975].

Aquatic invertebrates

EC50 (48 h) = 8.2 mg/L (geometric mean of EC0 and EC100; mean measured)

NOEC (7 -d, reprod.) = 1.09 mg/L (TWM measured)

In the only acute study conducted on daphnids (Ceriodaphnia dubia) over 48 h, the EC50 value was found to be < 10 mg/L [Collins 1994]. The other two studies resulting in EC50 values > 10 mg/L were run for 24 h only, hence are not considered to be reliable studies [Bringmann and Kühn 1982].

In a chronic study with Ceriodaphnia dubia following the US EPA method 1002.0 (Daphnid, Ceriodaphnia dubia, Survival and Reproduction Test), a 7 -d NOEC of 1.09 mg/L for effects on reproduction (and survival) was determined based on time weighted mean measured concentrations [Collins 1994]. The method is equivalent to OECD 211 using Ceriodaphia dubia which has a shorter generation period as Daphnia magna and is able to produce 3 broods witin 7 d.

Algae

ErC50 (72 h) = 17 mg/L (geometric mean measured)

ErC10 (72 h) = 3.7 mg/L (geometric mean measured)

The key study is a GLP-guideline study according to OECD 201 performed with the freshwater algae Desmodesmus subspicatus. The concentrations are analytically verified. The ErC50 was determined at 17 mg/L, the ErC10 at 3.7 mg/L (Muckle, 2013). Based on this result, the substance is supposed to be acutely harmful to aquatic algae. Non-reliable data are available on Microcystis aeruginosa and Scenedesmus quadricauda (Bringmann/Kühn). In these studies, major methodological deficiencies are obvious: pre-cultures up to 10 days old were used for the tests: cannot be in logarithmic growth phase anymore; test duration over 8 days instead of 3 (non-logarithmic); stagnant culture, shaken only once per day; number and spacing of tested concentrations not reported; "toxic threshold" concentration derived via absorption measurements equivalent to yield - growth rates not determined; accordingly, these studie must be regarded to be invalid.

Microorganisms

NOEC (Pseudomonas putida; 16 h) = 65 mg/L (unbuffered) / 800 mg/L (buffered)

In a cellular growth inhibition test using a pure bacteria culture of Pseudomonas putida, the toxicity threshold (TTC) was determined to be 65 mg/L (NOEC) under unbuffered conditions [Bringmann and Kühn 1977, 1980]. Upon neutralisation, the corresponding toxicity threshold (TTC, approximately equivalent to an EC03) was 800 mg/L. It must be assumed that sewage is neutralized to an acceptable pH range before discharge into STP. Further, sewage will have a buffer capacity on its own such that extreme pH values will not occur. Therefore, the TTC of 800 mg/L is the relevant value to be used in hazard and risk assessment for STP microorganisms.

In support of this value is the Zahn-Wellens test on inherent biodegradability (1977/1980). The initial concentration applied was 1000 mg/L COD (neutralized), and very rapid biodegradation was observed (90 % within 2 days, 100% within 5 days). This allows to exclude any relevant inoculum toxicity at this concentration.

In a 7-d toxicity pre-test preceding the main biodegradation study, 100 mg n-butylamine/L failed to inhibit the metabolism of the inoculum (here: activated sludge), indicated by highly efficient metabolic oxidation of glucose and n-butylamine itself (Yoshimura et al. 1980: see Section 5.2.1).

The other three pioneer studies referred to are based on pure cultures of non-standard test organisms (protozoae). All three organisms are of low relevance for the STP process (organisms feeding on bacteria). No standardized testing protocols do exist and thus reliability of the study outcome is not assessable. In conclusion, these are unsuitable test systems, and studies on Entosiphon and Chilomonas are disregarded [Bringmann and Kühn 1978 - 1982].

Summary of aquatic toxicity results for n-butylamine

Endpoint	Organism group	Species	Value [mg/L]	Reliability	Remarks	Source
FISH
96h LC50	Fish, freshwater	Lepomis macrochirus	32 (not buffered)	2 (Key study #1)	nominal, static	Dawson et al. 1975
96h LC50	Fish, freshwater	Pimephales promelas	268 (neutral)	1 (Supp. study)	analytically verified, flowthrough	Geiger et al. 1985
96h LC50	Fish, salt water	Menidia beryllina	24 (not buffered)	2 (Key study #2	nominal, static	Dawson et al. 1975
48h LC50	Fish, freshwater	Leuciscus idus	171 / 236 (not buffered)	3	nominal, static (2 studies)	Juhnke and Lüdemann 1978
48h LC0	Fish, freshwater	Leuciscus idus	100	4	nominal, static	Hoechst AG 1977
DAPHNIA
48h LC50	Aquatic invertebrates	Ceriodaphnia dubia	8.2	1 (Key study)	Analytically verifed, semi-static	Collins 1994 (Springborn)
24h EC50	Aquatic invertebrates	Daphnia magna	43	3	nominal, static	Bringmann and Kühn 1982
24h EC50	Aquatic invertebrates	Daphnia magna	75	3	nominal, static	Bringmann and Kühn 1982
7d NOEC mortality / reproduction (long-term)	Aquatic invertebrates	Ceriodaphnia dubia	1.5 (reprod.) 3 (mortality)	2 (Key study)	Analytically verified, semi-static	Collins 1994 (Springborn)
ALGA / CYANOBACTERIA
72h ErC50 / ErC10	algae	Desmodesmus subspicatus	17 / 3.7	1 (Key study)	nominal, static	Muckle 2013
8d EC0 (long-term)	algae	Scenedesmus quadricauda	0.54-0.55	3	nominal, static	Bringmann and Kühn 1977 -1980
8d EC0 (long-term)	cyano bacteria / blue algae	Microcystis aeruginosa	0.14	3	nominal, static	Bringmann and Kühn 1977 -1980
MICROORGANISM
16h NOEC	Microorganisms: bacteriae	P. putida	65 (alkaline) 800 (neutral)	2 (Key study)	nominal, static	Bringmann and Kühn 1977, 1980
72h EC0	Microorganisms: protozoae	Entosiphon sulcatum	8.8 (neutral)	3, disregarded	nominal, static	Bringmann and Kühn 1978, 1980
48h EC0	Microorganisms: protozoae	Chilomonas paramaecium	53 (neutral)	3, disregarded	nominal, static	Bringmann and Kühn 1980, 1981
20h EC0	Microorganisms: protozoae	Uronema parduzci	1752 (neutral)	3	nominal, static	Bringmann and Kühn 1980