Genetics And Ecotoxicology by Valery E. Forbes;

Author:Valery E. Forbes;
Language: eng
Format: epub
ISBN: 9781000162974
Publisher: CRC Press (Unlimited)
Published: 2020-01-15T00:00:00+00:00

Fig. 3 Toxicity of Pass Fourchon sediment: (a) Survival (mean number of survivors ±S.E. for three replicates starting with 10 worms each) and reproduction (mean number of offspring ± S.E. per replicate) in Streblospio benedicti exposed in the laboratory to control and Pass Fourchon sediment. ANOVA results: p= 0.041 for survival (arcsin √P transformed) and p = 0.274 for reproduction (√(n+0.5) transformed), (b) Survival of three-day old Palaemonetes pugio larvae exposed individually in 10 replicates to estuarine water containing a sediment extract of Pass Fourchon sediment in DMSO (extract of 180 mg sediment in 4 ml total volume), containing DMSO only (2µl in 4 ml total volume), or not containing any additions. To determine whether this selective pressure resulted in adaptation to the contamination, laboratory bioassays were conducted for all three species. In these experiments, resistance to PAH-rich Pass Fourchon sediment was quantified in organisms collected in Pass Fourchon (at one or more sites differing in sediment PAH levels) and in those obtained from the nearby control area. Resistance was then compared among these groups using survival analysis (e.g., Collett 1994), allowing the inclusion of right-censored data (results from individuals still alive at the point that the experiment was terminated) without biasing the population resistance estimates.

Two experiments were conducted with the darter goby. Fish were collected from the control area and three Pass Fourchon sites in the first experiment. The number of Pass Fourchon sites was reduced to one in the second experiment, making it possible to substantially increase the sample sizes. Resistance was quantified as survival time in laboratory exposures to Pass Fourchon sediment collected close to the discharge area. Survival analyses did not detect differences in survivorship curves among the groups in either of the two experiments (Fig. 4). There was, therefore, no evidence that G. boleosoma had adapted to the contamination at Pass Fourchon.

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