Hormesis: A Response to Low Environmental Concentrations of Petroleum Hydrocarbons

Abstract

Crab zoeae ( Rhithropanopeus harrisii ) were exposed to water-soluble fractions of jet fuel (JP5) for the first 5 days or for the duration of zoeal development (11 to 14 days). Short-term exposure or continuous exposure to low concentrations of petroleum hydrocarbons caused no increase in mortality or changes in development rate, and increased megalopal weight was characteristic of such groups. This phenomenon, termed "hormesis," is probably a generalized aspect of environmental stress etiology but has seldom been reported as such.

Effects of Exposure of Pink Shrimp, Farfantepenaeus duorarum, Larvae to Macondo Canyon 252 Crude Oil and the Corexit Dispersant

“…Survival following sublethal exposures of invertebrates varies based on species and life stage [21,54,62,63]. In the present study, F. duorarum nauplii exposed to sub-lethal amounts (23 mg L´1, LC 10 ) of CEWAFs for 24 h showed no difference in survival compared to controls over 39 days and was approximately 25% for both groups.…”

“…Delayed morality has been reported by other researchers in shrimp and crab larvae and embryos exposed to low levels of WSF for short periods with zoea being more sensitive than later developmental stages [21,54,62]. Other research has shown no survival effects in crab zoea following either short term exposure or continuous exposure to low concentrations of oil [63].…”

“…Other researchers have reported similar findings. Zoeal stages of the mud crab Rhithropanopeus harrisii increased following prolonged exposure to chronic, low levels of WSF, however short term exposure had no impact [63,64]. Minor differences (one day lags) in development times were also reported in Pandalus borealis larvae in early stages of development but effects decreased at later stages [21].…”

“…Developmental delays have been reported for invertebrate larvae exposed to PAHs [21,[63][64][65]. Developmental delays in invertebrates are typically accompanied by an increased period of intermolt following exposure to oil [58,64].…”

Chronic Sublethal Effects of San Francisco Bay Sediments on Nereis (Neanthes) arenaceodentata; Interpretative Guidance for a Growth End Point

“…For example, a reduction in growth is generally considered an adverse effect; but what if growth increases in response to contaminant exposure? Enhancement of a physiological process by exposure to low levels of contaminants is known as the Arndt-Schulz effect, "sufficient challenge," or hormesis (Laughlin, Ng, and Guard 1981). This effect is well documented (Stebbing 1981;Sanders, Laughlin, and Costlow 1984;Laughlin, Ng, and Guard 1981;Weis and Weis 1986) and is attributed to short-term overcompensation of homeostatic regulatory control mechanisms to an external challenge.…”