NOECs

Aquatic toxicity is reported in mg/L for Pimepha/espromealas (fathead minnow), 69-h LC q 7650 (17) for Daphnia magna (water flea), 48-h EC q 3310 (18) for Mjriophjllum spicatum (water milfoil), phytotoxicity (EC q for growth) 5962 (19) and for Pana breviceps (frog), no observed effect concentration (NOEC) 400 (20). LC q and EC q are lethal and effect concentrations, respectively, for 50% of the subjects tested. 

LAS homolog Acute fish toxicity (LC50) [mg/L] Long-time fish toxicity (NOEC) [mg/L] Acute daphnia toxicity (ECS0) (mg/L) Long-time daphnia toxicity (NOEC) (mg/L)... 

In a continual biocoenosis test (Riverine biocoenosis model) for LAS the biocoenotic NOEC value of >0.65 mg/L has been determined. The test was carried out with a starting concentration of 1.1 mg/L LAS/L over a period of 5 weeks. The NOEC value represents the effect caused by the original detergent and the effects caused by the catabolites as well [297]. The NOEC value shows that biocoenosis reacts more sensitively to compounds than the most sensitive laboratory species, which according to general opinion should not be generalized. 

Data sets on toxieity of organotins vary eonsider-ably from eompound to eompound, with dibutyltin being by far the best studied. Critieal end-points and speeies are as follows 0.007 mg/1 ehronie NOEC for Scenedes-mus subspicatus for monomethyltin (growth rate),... 

Effects on terrestrial organisms are reported only for mixtures of mono- and dimethyltin compounds (50 50 and 25 75), with 14-day LC50 values of 320 and >1000 mg/kg (as chloride), respectively, in the earthworm (Eisenia foetida), respective NOECs were 100 and 1000 mg/kg (as chloride) (Wilbury, 1995a,b, 1996). 

Green alga Scenedesmus subspicatus) MMTC 72-h NOEC (growth rate) 0.007 0.007 Oidersma et ai. (2003a)... 

Daphnid Daphnia magna) MMT(EHMA) 21-day NOEC (reproduction and mortaiity) 0.14 0.05 de Roode de Haan (2004a)... 

Diatom Skeietonema costatum) MMTC 96-h NOEC (growth rate) 1.0 1.0 Morton internationai, inc. (1996a)... 

Daphnid (Daphnia magna) DBTC 21-day NOEC (survival and reproduction) 0.015 = highest concentration tested 0.015 ABC (1990b)... 

Medaka (Oryzias latipes) DBTC 28-day NOEC (mortality, growth, and behaviour) 1.8 1.8 Wester Canton (1987)... 

Rainbow trout (Oncorhynchus mykiss) Marine DBTC 110-day NOEC (survival and growth) 0.04 0.04 de Vries et al. (1991)... 

Sheepshead minnow (Cyprinodon variegatus) DBTC 191-day NOEC (survival, growth, and fecundity) 0.45 0.45 Elf Atochem NA (1992)... 

Monomethyltirf. Acute toxicity studies were identified for monomethyltin for algae, invertebrates, and fish. Chronic NOECs were available for algae and invertebrates. A chronic NOEC of 0.007 mg/1 for monomethyltin chloride in Scenedesmus subspica-tus was the lowest reported result. Since there were no long-term test results available for fish, it was necessary to apply an uncertainty factor of 50 to the critical study. 

Dibutyltin. A larger data set exists for dibutyltin, including both acute and long-term test results. The lowest concentration identified was a chronic NOEC of 0.015 mg/1 for Daphnia magna exposure to dibutyltin chloride. Long-term values were available across three trophic levels, and, therefore, an uncertainty factor of 10 was considered appropriate. 

MMTC 0.007 mg/1 chronic NOEC for Scenedesmus subspicatus (Oldersma et al., 2003a) 50 0.1... 

MOTC 0.003 mg/i chronic NOEC for Scenedesmus subspicatus (Oidersma et ai., 2004b) 50 0.06... 

Dioctyltirv. Acute toxicity studies were identified for dioctyltin for invertebrates and fish. Chronic NOECs were available for algae and invertebrates. 

Silva, E., Rajapakse, N., and Kortenkamp, A. (2002). Something from nothing — Eight weak estrogenic chemicals combined at concentrations below NOECs produce significant mixture effects. Environmental Science and Technology 36, 1751-1756. 

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