Carbon black

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

Since bulk and nanoforms of carbon black are not soluble in water, it is not possible to carry out many standard ecotoxicity tests. Their low toxicity neccessitates that high concentrations be tested in order that toxicity might be detected. This is compounded by low pH of some aqueous suspensions which makes the testing protocol even more difficult. Nevertheless, results with fish tests with treated and untreated forms of carbon black have established that a fish No Effect Concentrations (NOECs) will be greater than 1000 mg/L for aqueous suspensions, and greater than 10,000 mg/L for water accommodated filtrates. The Daphnia results from water accommodated filtrates indicate an EC50 of 5600 mg/L (original suspension concentration), which is attributed to the pH of the solution. The algal test results, also from water accommodated filtrates, show no adverse effect at the highest concentration tested, an original suspension concentration of 10,000 mg/L. Given the phys-chem and compositional similarities between the bulk and nanoforms, as well as the larger particle size of the bulk form, it is not expected that the non nanoforms of carbon black will have higher toxicity than the nanoforms.

Description of key information

Since Carbon Black is not soluble in water, it is not possible to carry out many standard ecotoxicity tests for this substance. Its low toxicity, requiring high concentrations to be tested in order that toxicity might be detected, and the low pH of some aqueous suspensions makes the testing protocol even more difficult. Nevertheless, results with fish tests have established that a fish LC50 will be greater than 1000 mg/L for aqueous suspensions, and greater than 10,000 mg/L for water accommodated filtrates. The Daphnia results from water accommodated filtrates indicate an EC50 of 5600 mg/L (original suspension concentration), which is attributed to the pH of the solution. The algal test results, also from water accommodated filtrates, show no adverse effect at the highest concentration tested, an original suspension concentration of 10,000 mg/L.