The effects of diffusible creosote-derived compounds on development in Pacific herring (Clupea pallasi)

The effects of diffusible creosote-derived compounds from weathered creosot e-treated pilings on embryonic development in the Pacific herring were inve stigated. Parameters used to evaluate toxicity included embryonic developme nt, cardiac function, embryo/larval activity (movement of developing embryo s), hatching success, and larval morphology at hatch. For acute exposures, embryos were incubated in seawater containing either creosote-treated wood (creosote) or untreated wood (wood control), or seawater alone (control). A ll embryos adhering directly to creosote-treated wood and 40-50% of embryos not adhering to the creosote-treated wood failed to develop beyond the fir st few days of incubation. For surviving embryos, a 93% reduction in heart rate, and moderate to marked arrhythmia was observed. Surviving embryos als o exhibited both an increase in frequency and an alteration in pattern of e mbryo/larval movement, with most embryos exhibiting tremors as compared wit h the vigorous movements of the control embryos. Cardiac function and embry o/larval movements of embryos exposed to untreated wood were not significan tly different from controls. The hatching rate of embryos exposed to creoso te was 90% lower than control embryos and 72.4% lower than embryos exposed to untreated wood, and the LC50 for hatching success was 0.05 mg/l. Partial hatching (incomplete hatch) was observed in 15-20% of embryos exposed to c reosote. All of the hatched larvae exposed as embryos to creosote exhibited morphological deformities, including scoliosis, pericardial edema and/or a scites. Similar effects were observed in embryos collected from creosoted p ilings in San Francisco Bay, with a 72% decrease in hatching success compar ed with embryos collected from the Bay and severely deformed larvae. To inv estigate the combined effects of creosote and salinity on hatching success, larval morphology, and cardiac function, embryos were exposed to a subleth al concentration of creosote (0.003 mg/l) at three salinities; sub-optimal (8 parts per thousand (ppt)), optimal (16 ppt), and high salinity (28 ppt). The presence of creosote decreased hatching success at all three salinitie s, but the effect was greatest at 8 ppt (34% reduction) and the least in 28 ppt (14% reduction). The increased incidence of morphological abnormalitie s was also smallest at the high salinity (10% compared with 24 and 33% in 8 and 16 ppt). While exposure to creosote resulted in reduced heart rates at all three salinities, no additive effect of creosote and salinity was obse rved. (C) 2000 Elsevier Science B.V. All rights reserved.