2-Thiophenecarboxylic acid, 3-[[(2-methoxy-2-oxoethyl)amino]sulfonyl]-, methyl ester

Long-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Justification for type of information:

QSAR prediction: migrated from IUCLID 5.6

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Report date:

2014

Materials and methods

Principles of method if other than guideline:

The chronic toxicity on Daphnia was estimated by using ECOSAR.
ECOSAR predicts the aquatic toxicity of chemicals based on their similarity of structure to chemicals for which the aquatic toxicity has been previously measured. Most SAR calculations in the ECOSAR Class Program are based upon the octanol/water partition coefficient (Kow). The reliability of ECOSAR predictions is evaluated in terms of descriptor range (Kow range) and MW.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

methyl 3-[(2-methoxy-2-oxoethyl)sulfamoyl]thiophene-2-carboxylate

EC Number:

600-780-8

Cas Number:

106820-63-7

Molecular formula:

C9H11NO6S2

IUPAC Name:

methyl 3-[(2-methoxy-2-oxoethyl)sulfamoyl]thiophene-2-carboxylate

Test organisms

Test organisms (species):

Daphnia magna

Study design

Test type:

other: in silico predictions

Results and discussion

Effect concentrations

Dose descriptor:

other: Chronic Value

Effect conc.:

93.34 mg/L

Remarks on result:

other: Reliable

Any other information on results incl. tables

ECOSAR ChV (mg/L) = 93.34

Maximum LogKow = 8.0

Maximum MW = 1000.

Reliability assessment: reliable

ECOSAR contains a library of class-based QSARs for predicting aquatic toxicity, overlaid with an expert decision tree for selecting the appropriate chemical class. The QSARs in ECOSAR are based on a linear mathematical relationship between the predicted log Kow values and the corresponding log of the measured toxicity values (mmol/L) for a suite of training set chemicals within each class of interest. The ChV, or Chronic Value, is defined as the geometric mean of the no observed effect concentration (NOEC) and the

Business confidential - QSAR in silico predictions

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lowest observed effect concentration (LOEC). This can be mathematically represented as: ChV = 10^([log (LOEC x NOEC)]/2).

For chronic exposures, the applicable log Kow range to derive reliable quantitative (numeric) values is extended up to log Kow 8.0. If the log Kow of the chemical exceeds 8.0 which generally indicate a poorly soluble chemical, “no effects at saturation” are expected in saturated solutions even with long-term exposures (Tolls et al., Integr Environ Assess Manag, 2009, 5(3),374-378).

Molecular weight may also be considered to determine the absorption cut off limit for aquatic organisms. As the molecular weight of a chemical increases above 600, passive absorption through respiratory membranes decreases significantly. Therefore, for chemicals with molecular weights above 1000, it has been assumed that such absorption is negligible. Therefore, ECOSAR is not recommended for chemicals with molecular weights above 1000.

ECOSAR assigned 2-Thiophenecarboxylic acid, 3-[[(2-methoxy-2-oxoethyl)amino]sulfonyl]-, methyl ester to the class of esters, thiophenes and amides. According to a precautionary approach, the predicted ChV value was selected as the lowest ChV value (amides ChV) among the three ChV values of the three classes. Thus, ECOSAR predicted a ChV = 93.34 mg/L, and the prediction is considered reliable since the target does not exceed the upper logKow value of 8.0 (the consensus logKow value estimated in the present report is equal to 0.62) nor the upper MW value of 1000 (the MW value is equal to 293.31).

Applicant's summary and conclusion

Conclusions:

ECOSAR predicted a ChV = 93.34 mg/L, and the prediction is considered reliable.