References - trdoer40203

Daphnia magna is the only tested freshwater invertebrate species for which

the acute toxicity of naphthalene has been determined (USEPA 1982). The

reported 48-hr EC50 is 8,570 ug/L.

Flow-through tests were conducted with measured concentrations for the

rainbow trout and the fathead minnow. The trout appeared to be more sensitive

with a 96-hr LC50 of 2,300 ug/L. The 96-hr LC50 for the fathead minnow tested

at 14 C degrees centigrade was 4,900 ug/L, at 24 C the LC50 was 8,900 ug/L.

The LC50 of 150,000 ug/L for the mosquitofish appears to be atypical but the

result cannot be discounted.

LC50 (96 h) values for the polycheate, Neanthes arenaceodentata, (Pacific

oyster), and the grassshrimp are 3,800, 199,000, and 2,350 ug/L, respectively.

The 24-hr LC50 values for one fish and two saltwater shrimp species range from

2,400 to 2,600 ug/L.

With the exception of the mosquitofish and the Pacific oyster, all LC50 and

EC50 values, regardless of test method, fall within the narrow range of 2,300 to

8,900 ug/L for nine freshwater and saltwater species.

Tests have been conducted to determine the chronic toxicity of naphthalene

to ecological receptors. An embryo-larval test has been conducted with the

fathead minnow and the resultant chronic value is 620 ug/l. When this

concentration is divided by the geometric mean LC50 value of 6,600 ug/L for

this species an acute-chronic ratio of 2 is obtained. No other species have been

tested under chronic conditions.

There is only one reported test that determined an apparent equilibrium

bioconcentration factor for naphthalene. After 9 days, the bioconcentration

factor for a copepod was 5,000. Bioconcentration data for other species for

exposures of 1 hr to 1 day range from 32 to 77 and indicate that equilibrium does

not occur rapidly when those results are compared to the 9 day value of 5,000.

References

U.S. Environmental Protection Agency. (1982). "An exposure and risk

assessment for benzo(a)pyrene and other polycyclic aromatic hydrocarbons,"

Volume IV. Final Draft Report, Washington, DC.

D51

Appendix D Toxicological Profiles