Toxicity of chlorinated benzenes to fathead minnows (Pimephales promelas).

Abstract

The toxicities of several chlorinated benzene compounds to fathead minnows (Pimephales promelas) were determined. Chronic toxicities were estimated from 32–33 day embryo through early juvenile development exposures. The ranges between the highest no observable effect concentration (NOEC) and lowest observed effect concentration (LOEC) were 1,000–2,300, 570–1,000, and 240–410 μg/L for 1,3-dichlorobenzene (1,3-DCB), 1,4-dichlorobenzene (1,4-DCB), and 1,2,3,4-tetrachlorobenzene (1,2,3,4-TCB), respectively. Pentachlorobenzene (Penta-CB) and hexachlorobenzene (HCB) were non-toxic at the highest concentrations of 55 and 4.8 μg/L (near water saturation), respectively, that could be maintained in the test chambers. The tissue concentrations associated with the NOEC and LOEC for 1,3-DCB, 1,4-DCB and 1,2,3,4,-TCB were 120–160, 70–100, and 640–1,100 μg of chemical per gram of fish tissue (wet weight), respectively. The mean Penta-CB and HCB tissue concentration obtained at the NOEC of 55 and 4.8 μg/L were 390 and 97 μg/g, respectively. Mean bioconcentration factors obtained in these tests were 97, 110, 2,400, 8,400 and 22,000 for 1,3-DCB, 1,4-DCB, 1,2,3,4-TCB, Penta-CB and HCB, respectively. At a Penta-CB concentration of 130 μg/L (near water saturation) in a six day exposure conducted in the reservoir of the chemical saturating apparatus and control, juvenile fathead minnow behavior was affected and lipid content was reduced when compared to the control. Ninety-six hr LC50 values, obtained with juvenile fish, for 1,3-DCB, 1,4-DCB, and 1,2,3,4-TCB were 7,800, 4,200, and 1,100 (μg/L, respectively.