Perrine Geraudie

In Vivo Effects of Environmental Concentrations of Produced Water on the Reproductive Function of Polar Cod (Boreogadus saida)

Offshore oil and gas drilling processes generate operational discharges such as produced water (PW), a complex mixture of seawater with polycyclic aromatic hydrocarbons (PAH) and alkylphenols (AP). Some of these compounds may interact with the endocrine system of marine organisms and alter reproductive functions. In this study, polar cod were exposed for up to 28 d to a mixture of PAH, alkylated PAH, and AP simulating the composition of North Sea PW, at low and high concentrations (1:2000 and 1:1000 dilution of the original concentrate, respectively). Potential adverse effects of PW on polar cod physiology were investigated through biomarkers of biotransformation (hepatic ethoxyresorufin O-deethylase [EROD] activity and bile PAH metabolites), endocrine disruption (plasma vitellogenin [VTG] levels and sex steroid concentrations), and gonad histology. Plasma sexual steroid levels in fish were not markedly affected by PW exposure, while higher plasma VTG concentrations were measured in females exposed to the high PW treatment for 7 and 28 d. In males exposed to the higher PW concentration, inhibition of spermatogenesis was observed after 28 d in addition to increase of melano-macrophage occurrence in testis. Females exposed to the high PW treatment for 21 d showed a significant increase of atresia incidence. Finally, a significant decrease in oocyte number was observed in high PW exposed female ovaries after 28 d of exposure.

Acute and long-term biological effects of mechanically and chemically dispersed oil on lumpsucker (Cyclopterus lumpus).

Concentration dependent differences in acute and long-term effects of a 48 h exposure to mechanically or chemically dispersed crude oil were assessed on juvenile lumpsucker (Cyclopterus lumpus). Acute or post-exposure mortality was only observed at oil concentrations representing higher concentrations than reported after real oil spills. Acute mortality was more apparent in chemically than mechanically dispersed oil treatments whereas comparable EC50s were observed for narcosis. There was a positive correlation between EROD activity and muscle PAH concentration for the lower oil concentrations whereas higher concentrations inhibited the enzyme activity. The incidence of gill tissue lesions was low with no difference between dispersion methods or oil concentrations. A concentration dependent decrease in swimming- and feeding behavior and in SGR was observed at the start of the post-exposure period, but with no differences between corresponding oil treatments. Three weeks post-exposure, fish from all treatments showed as high SGR as the control fish.

Brain cytochrome P450 aromatase activity in roach (Rutilus rutilus): Seasonal variations and impact of environmental contaminants

P450 aromatase catalyses the conversion of C19 androgens to C18 estrogens which is thought to be essential for the regulation of the reproductive function. In this study, brain aromatase activity (AA) was measured monthly over a reproductive cycle in wild roach (Rutilus rutilus) sampled in a reference site in Normandy. AA peaked during the breeding season, reaching 35 fmol mg(-1)min(-1) in both male and female fish, and was low during the rest of the year except for a significant rise in October. AA was correlated with ovary maturation (measured either as gonado-somatic index or by histological analysis of the gonads) and plasma sex-steroid levels (11-ketotestosterone in males and 17-β-estradiol in females). Measurements of AA in polluted sites showed that activity was significantly upregulated in sites with fish showing high levels of plasma vitellogenin and large proportion of intersexuality (20-50%) thus suggesting the occurrence of estrogenic compounds and their involvement in AA modulation.

Endocrine effects of the tapeworm Ligula intestinalis in its teleost host, the roach ( Rutilus rutilus )

The effects of parasite infection by the cestode Ligula intestinalis on the reproductive function and endocrine system of wild roach Rutilus rutilus were evaluated. Gonad maturation, plasma vitellogenin, plasma steroid concentrations (i.e. progesterone, 11-keto-testosterone and 17-beta-estradiol) and brain aromatase activity were investigated in relation with parasitization. A low prevalence (8%) of ligulosed roach and a moderate impact of parasitization (mean parasitization index of 8.8%) were found in the studied population. Inhibition of gonad maturation generally resulted from infestation but 5% of the ligulosed roach nevertheless reached maturity. Main sex steroid plasma content was depleted in both genders. Male 11-keto-testosterone, female 17-beta-estradiol and progesterone plasma concentrations of both genders were, respectively, 27, 5 and 3 times lower in ligulosed fish when compared to their non-infected counterparts. Progesterone levels were negatively correlated with the parasitization index in females. Brain aromatase activity of infected roach was reduced to 50% of that of the non-infected fish. These results demonstrate significant negative effects on the reproductive function of wild roach infected by the tapeworm L. intestinalis collected from a site with low contamination.

Seasonal variations and alterations of sex steroid levels during the reproductive cycle of male roach (Rutilus rutilus)

Seasonal variations of plasma steroid concentrations i.e. progesterone (P), 11-ketotestosterone (11-KT) and 17-β-estradiol (E2) were determined immunoenzymatically during a whole reproductive cycle in male roach (Rutilus rutilus) caught in a reference site. Plasma 11-KT concentrations were significantly correlated with gonad growth, expressed as the gonado-somatic index (R² =0.60; p<0.05) and highest concentrations (757 ± 99 pg ml⁻¹ ) coincided with the final testis maturation in March. E2 and P concentrations peaked once during the reproductive cycle. E2 synthesis was significantly induced during the spawning period while P concentration peaked at the very start of the gametogenesis (June) thus suggesting specific roles of these steroids in the reproductive cycle. Comparison of reference levels were then made with plasma steroid concentrations from male roach sampled in polluted areas in the North of France. A significant decrease of E2 (50-60%) and 11-KT (76-84%) was measured, indicating that endocrine disrupting compounds may have interfered with the normal sex steroid synthesis. Contrary to the E2 and 11-KT sex steroids, plasma P concentration was not significantly affected in fish inhabiting impacted areas.

Biological effects of mechanically and chemically dispersed oil on the Icelandic scallop (Chlamys islandica)

This study aimed to simulate conditions in which dispersant (Dasic NS) might be used to combat an oil spill in coastal sub-Arctic water of limited depth and water exchange in order to produce input data for Net Environmental Benefit Analysis (NEBA) of Arctic and sub-Arctic coastal areas. Concentration dependent differences in acute responses and long-term effects of a 48h acute exposure to dispersed oil, with and without the application of a chemical dispersant, were assessed on the Arctic filter feeding bivalve Chlamys islandica. Icelandic scallops were exposed for 48h to a range of spiked concentrations of mechanically and chemically dispersed oil. Short-term effects were assessed in terms of lysosomal membrane stability, superoxide dismutase, catalase, gluthatione S-transferases, glutathione peroxidases, glutathione reductase, glutathione, total oxyradical scavenging capacity, lipid peroxidation and peroxisomal proliferation. Post-exposure survival, growth and reproductive investment were followed for 2 months to evaluate any long-term consequence. Generally, similar effects were observed in scallops exposed to mechanically and chemically dispersed oil. Limited short-term effects were observed after 48h, suggesting that a different timing would be required for measuring the possible onset of such effects. There was a concentration dependent increase in cumulative post-exposure mortality, but long-term effects on gonadosomatic index, somatic growth/condition factor did not differ among treatments.

A new in vitro screening bioassay for the ecotoxicological evaluation of the estrogenic responses of environmental chemicals using roach (Rutilus rutilus) liver explant culture

There is growing evidence that many chemicals released in the environment are able to disturb the normal endocrinology of organisms affecting the structure and function of their reproductive system. This has prompted the scientific community to develop appropriate testing methods to identify active compounds and elucidate mechanisms of action. Of particular interest are in vitro screening methods that can document the effects of these endocrine disrupting compounds on fish. In this study, an in vitro bioassay was developed in the roach (Rutilus rutilus) for evaluating the estrogenicity or antiestrogenicity potency of environmental pollutants by measuring vitellogenin (VTG) induction in cultured liver explants. The cell viability was assessed by the measurement of nonspecific esterase activity using a fluorescein diacetate hydrolysis assay. Results showed that explants could be cultured for 72 h without any significant loss of activity. Dose‐dependent responses have been measured with estrogenic model compounds such as 17‐β‐estradiol (E2) and 17‐α‐ethynylestradiol (EE2) or antiestrogenic compounds such as tamoxifen. Lowest observable effective concentrations were 1 nM for E2, 1 nM for EE2, and 100 nM for tamoxifen, showing a good sensitivity of the test system. Estrogenicity of butyl 4‐hydroxybenzoate, 4‐nonylphenol, and bisphenol A was tested. bisphenol A (100 μM) or butylparaben induced a twofold increase in VTG production when compared with 100 nM E2, whereas this production was only 20% with 100 μM 4‐nonylphenol. Overall, this study shows that the bioassay could provide valuable information on endocrine disrupting chemicals including metabolites and mixtures of compounds.

Biological effects of marine diesel oil exposure in red king crab (Paralithodes camtschaticus) assessed through a water and foodborne exposure experiment

Shipping activities are expected to increase in the Arctic Seas. Today, the majority of vessels are using marine diesel oil (MDO) as propulsion fuel. However, there is a general lack of knowledge of how cold-water marine species respond to acute exposures to MDO. Arctic red king crabs (Paralithodes camtschaticus) were exposed to mechanically dispersed MDO in a flow-through exposure system for one week followed by three weeks of recovery. Observations of increased movements in exposed crabs were interpreted as avoidance behaviour. Further, glutathione peroxidase activity increased in high exposed crab, the catalase activity showed an insignificant increase with exposure, while no differences between groups were observed for lipid peroxidation and acetylcholinesterase activity. After three weeks of recovery in clean seawater, polycyclic aromatic hydrocarbons concentrations in the crabs were significantly reduced, with no specific biomarker responses in exposed groups compared to the control. The results suggest that effects from instantaneous MDO spill only will have short-term effects on the red king crab.

Effects of chlordecone on 20-hydroxyecdysone concentration and chitobiase activity in a decapod crustacean, Macrobrachium rosenbergii

Chlordecone (CLD) is an organochlorine insecticide abundant in aquatic environment of the French West Indies. However, few studies have investigated its impact on freshwater invertebrates. Whereas CLD is suspected of inducing endocrine disruption, this work aimed to study the effects of environmentally relevant concentrations of CLD on the 20-hydroxyecdysone (20-HE) hormone concentration and on the chitobiase activity, both having key roles in the molting process of crustaceans. In addition, the bioaccumulation of CLD was measured in the muscle tissue of Macrobrachium rosenbergii to underline potential dose-response relationship. The results have shown that CLD was bioaccumulated in exposed organisms according to a trend to a dose-response relationship. Moreover, it was observed that CLD decreased the 20-HE concentration in exposed prawns when compared to control, whatever the duration of exposure, as well as it inhibited the chitobiase activity after 30days of exposure. The present study indicates that CLD could interfere with molting process of M. rosenbergii by disturbing the 20-HE concentration and the activity of chitobiase, suggesting consequences at the long term on the shrimp development. This study also confirmed that CLD could be an endocrine disruptor in decapod crustaceans, as it was already observed in vertebrates.

Biomarker modulation associated with marine diesel contamination in the Iceland scallop (Chlamys islandica)

The decrease of ice cover in the Arctic will lead to an increase of ship traffic in the upcoming decades. Consequently, oil pollution is expected. In this context, the goals of this study were to evaluate the biological impact of marine diesel contamination and, on this basis, to determine analytical tools of interest (biomarkers) for future biomonitoring of diesel spills. Using a 7-day contamination protocol, this study investigated biochemical modulations in the digestive gland of the Iceland scallop (Chlamys islandica). Incorporation of contaminants was verified assessing haemolymph metabolites. Results showed a response of glutathione-S-transferase to contamination suggesting detoxification processes and the suitability of such a tool for diesel spill biomonitoring. The lack of modulation of superoxide dismutase activity and lipid peroxidation suggests no oxidative stress and the unsuitability of these molecular tools for biomonitoring.