Lowest-observable effect concentrations

Rainbow trout, Ortcorhyrtchus mykiss 5—40 Lowest observed effective concentrations for producing adverse effects on gills and kidneys (5 pg/L), liver and heart (10 pg/L), enzyme activities and other tissues (20-40 pg/L) 24... 

TCDD concentrations in eggs of seven species after exposure as fertilized eggs to nominal concentrations of 9-285 ng 2,3,7,8-TCDD/L for up to 540 h. Lowest observed effect concentration (LOEC) in ng/kg FW associated with adverse effects on su rvival or growth 32 days post exposure vs. no observed effect concentration (NOEC) in ng/kg FW Lake herring, Coregonus artedi 270 vs. 175 Fathead minnow, Pimephales promelas ... 

SPY sulfapyridine, SDZ sulfadiazine, SMX sulfamethoxazole, SMZ sulfamethazine, SCP sulfachloropyridazine, STZ sulfathiazole, SCT sulfacetamide, AcSMX N -acetylsulfamethoxazole, AcSDM N -acetylsulfadimethoxine, AcSDZ N -acetylsulfadiazine, EC50 Median effective concentration (mg/L), LC50 Median lethal concentration (mg/L), NOEC No-observed-effect concentration (mg/L) LOEC lowest-observed-effect concentration (mg/L), h hours, min minutes, d days... 

To derive PAH criteria, a safety factor of 0.1 was used with most chronic data, but ranged between 0.1 and 0.01 of the lowest observed effective concentration in freshwater and 0.1 and 0.5 in marine waters. 

NOEC indicates no-observed-effect concentration. ftLOEC indicates lowest-observed-effect concentration. cMean of eight toxicity tests. 

TEC, threshold effect concentration, calculated as the geometric mean of the no-observable effect concentration (NOEC) and the lowest-observable effect concentration (LOEC) BA Battery Approach PW porewater WS whole sediments. 

LOEC the Lowest Observed Effect Concentration where induced luminescence is at least twice higher than that of controls ... 

ISWMP Integrated Solid Waste Management Plans LOEC Lowest observed effect concentration L/S liquid to solid ratio... 

Lowest observed effect concentration, that is the lowest concentration in the tested series at which a biological effect is observed (i.e., where the mean value for the observed response is significantly different from the controls). It is one of the tested concentrations obtained, for example, after analysis of variance and multiple comparison statistical testing (e.g, Dunnett test). Volume 1(3,4), Volume 2(8,11). 

Within the USEPA s EPI Suite, descriptions of basic physical-chemical properties for 2,4-dichloroaniline (DCA CAS No. 554007), pentachlorophenol (PCP CAS No. 87865), nonylphenol (NP CAS No. 104405), and linear alkylbenzenesulfonate (C12 LAS CAS No. 25155300) were obtained using the EPI Suite (Table 3.1), whereas acute and chronic toxicity estimates for the median effective and chronic effect concentrations (the geometric mean between chronic lowest-observed-effect concentration [LOEC] and no-observed-effect concentration [NOEC]) and for fish, daphnids, and algae for each substance were estimated from ECOSAR (Table 3.2). These compounds were chosen based on their widespread use. 

In addition, the size of the effect at the Lowest Observed Effect Concentration (LOEC) might vary considerably from test to test. 

LOEC/L Lowest-observed-effect concentration/level. The lowest concentration of an agent used in a toxicity test that has a statistically significant effect on the exposed population of test organisms, compared with the controls. 

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