Are WWTPs effluents responsible for acute toxicity? Seasonal variations of sediment quality at the Bay of Cádiz (SW, Spain).

Adverse effects of wastewater treatment plants (WWTPs) on sediment quality at the Bay of Cádiz (SW, Spain) were evaluated by a battery of acute bioassays and chemical contamination. Five sites directly affected by WWTPs effluents and one control site were chosen. Results evidenced clear deterioration of ecological sediment quality parameters and possible effects on aquatic communities towards WWTPs areas. Acute toxicity and chemical contamination varied significantly across the studied sites and differed between winter and summer seasons. The Bay of Cádiz is contaminated by PAHs, metals, detergents (SAS) and pharmaceutical products. Principal Component Analyses indicated metals, SAS and pharmaceutical products as the major environmental stresses. Sea-urchin embryo-larval and microalgae growth rate were the most sensitive bioassays to evaluate resuspension of contaminants (elutriate) from bulk sediment. Amphipods mortality and Microtox(®) solid phase test bioassays were recommended to evaluate bulk sediment quality. Therefore, the use of multiple-bioassays, sensitive to sediment pollution, may provide complementary information to diagnose environmental factors that can impair aquatic communities. The battery of bioassays is recommended to assess and monitor marine sediments directly affected by a mixture of contaminants released from WWTPs.

A candidate short-term toxicity test using Ampelisca brevicornis to assess sublethal responses to pharmaceuticals bound to marine sediments.

Lethal and sublethal responses related to different phases of metabolism (phases I and II enzymatic activities), neurotoxicity (acetylcholinesterase activity), oxidative stress (lipid peroxidation and antioxidant enzyme activities), and genetic damage (DNA strand breaks) were analysed to assess the possible adverse effects of pharmaceuticals bound to marine sediments. The crustacean amphipod Ampelisca brevicornis was chosen as the bioindicator species. Organisms were exposed for 10 days to sediment spiked with pharmaceutical compounds frequently used and previously detected in the environment: carbamazepine (CBZ), ibuprofen (IBP), fluoxetine (FX), 17α-ethynylestradiol (EE2), propranolol (PRO), and caffeine (CAF). Short-term bioassay to evaluate amphipod mortality was recommended to assess pollution by CBZ, FX, and PRO. IBP and PRO were metabolized by phases I and II detoxification enzymatic activities. Oxidative stress was caused by PRO and CAF. Contrary to expected results, DNA damage (strand breaks) decreased after the exposure of amphipods to sediment spiked with IBP, FX, EE2, PRO, and CAF (including environmental concentrations). FX was neurotoxic to amphipods. The battery of biomarkers tested allowed the assessment of bioavailability, oxidative stress, genotoxicity, and neurotoxicity of the pharmaceuticals analysed. The results of this study suggested that pharmaceutical products at concentrations currently found in the environment might cause a wide variety of adverse effects (based on laboratory studies). The results obtained here are useful for environmental risk assessment of marine sediments contaminated by pharmaceuticals. Nevertheless, more research is needed using field-based marine sediments.

Bioavailability, oxidative stress, neurotoxicity and genotoxicity of pharmaceuticals bound to marine sediments. The use of the polychaete Hediste diversicolor as bioindicator species.

A set of "early warning responses", measured as biomarkers of exposure and effect, was applied in the marine bioindicator Hediste diversicolor, in a way to assess the environmental quality of sediment affected by pharmaceutical contamination. Sublethal responses were determined in the sea-worms after 14-days of exposure to sediment spiked with some of the most representative pharmaceutical products found in the environment: carbamazepine (CBZ), ibuprofen (IBP), fluoxetine (FX), 17α-ethynylestradiol (EE2) and propranolol (PRO), including the environmental concentrations. Phases I (ethoxyresorufin O-deethylase - EROD and dibenzylfluorescein dealkylase - DBF) and II (glutathione S-transferase - GST) of the metabolism, antioxidant system (glutathione peroxidase - GPX and glutathione reductase - GR), neurotoxicity (acetylcholinesterase - AChE) and oxidative effects (lipid peroxidation - LPO and DNA damage strand breaks) were selected to evaluate the sublethal responses in the sea-worms. FX, EE2 and PRO were detoxified by the phase I of the metabolism (EROD activity). On the other hand, phase II (GST-activity) did not respond in sea-worms exposed to pharmaceutical products, except for the environmental concentrations of CBZ (activation) and PRO (deactivation). Neurotoxicity was induced in sea-worms exposed to EE2 (only the environmental concentrations), FX, IBP and CBZ. Oxidative effect determined as LPO increased in sea-worms exposed to environmental concentrations of IBP, EE2 and PRO. Genetic damage increased in sea-worms exposed to IBP and diminished for FX, EE2 and PRO. Our results indicated the toxicity of pharmaceutical products and recommended the battery of biomarkers and the bioindicator specie H. diversicolor for the environmental quality assessment of sediment affected by pharmaceutical contamination.