Presence of Cocaine in the Tissues of the European Eel, Anguilla anguilla, Exposed to Environmental Cocaine Concentrations

Abstract

The presence of illicit drugs and their metabolites in surface waters has to be considered a new type of hazard, still unknown, for the aquatic ecosystem, due to the potent pharmacological activities of all the illicit drugs. Our research was therefore aimed at evaluating the impact of illicit drugs on the aquatic fauna, till now still undervalued. To this aim, we verified the ability of the European eel (Anguilla anguilla), a well-known biomonitor of environmental contamination, to bioaccumulate cocaine, one of the most abundant illicit drugs found in surface waters. Silver eels were exposed to a nominal cocaine concentration of 20 ng/l for one month; at the same time, control, carrier and post-exposure recovery groups were made. Brains, gills, liver, kidney, muscle, gonads, spleen, digestive tract and sections of dorsal skin were assayed by high-pressure liquid chromatography (HPLC). Cocaine was found in the tissues of the treated eels, and, at low concentrations, in almost all tissues of post-exposure recovery eels. These results indicate that cocaine is able to accumulate into the eel tissues; its presence suggests potential risks for eels, since cocaine could affect their physiology and contribute to their decline, and for humans, consuming contaminated fis

Pharmaceuticals and other anthropogenic tracers in surface water: A randomized survey of 50 Minnesota lakes

“…Although the biological effects of cocaine in the aquatic environment are not known, it has been shown to accumulate in eel tissue when these organisms are exposed to concentrations similar to those reported in the present study, raising concerns that long‐term exposure to this neurologically active chemical might affect the reproductive behavior of aquatic organisms . Benzoylecgonine caused sublethal but “notable adverse effects” in studies of freshwater mussels at 500 ppt . Benzoylecgonine concentrations up to 740 ppt have been found in effluent‐dominated surface water.…”

Histological and hormonal changes in the European eel (Anguilla anguilla) after exposure to environmental cocaine concentration

“…A stock solution of 0.006 mg mL −1 cocaine free‐base in ethanol was prepared (McClung & Hirsh ; Capaldo et al . ). A control group was kept untreated, exposed to tap water; a treated group was exposed daily to a nominal concentration of 20 ng L −1 cocaine (1 mL of the stock solution, administered directly into the aquarium, every 24 h, after renewing the water); a vehicle control group was exposed daily to the same concentration of ethanol as the treated group, in the same conditions.…”

“…They were acclimated to the laboratory for 1 month, as previously described (Capaldo et al . ), and kept in 300‐L glass aquaria under a natural photoperiod, in dechlorinated, well‐aerated tap water, with the following physicochemical conditions: salinity 0, ammonia <0.1 mg L −1 , temperature 15 °C ± 1 °C, pH 7.3 ± 0.2, dissolved oxygen 8.1 ± 0.5 mg L −1 ; Mean ± SD). The water was not recycled but renewed every 24 h. As eels undergo a natural starvation period during the silver stage, they were not fed.…”

“…The epidermis and the intestine were chosen because they bioaccumulate cocaine after a chronic exposure (Capaldo et al . ). Together with gills, the epidermis and the intestine are the first interfaces of the organism exposed to the aquatic environment and therefore a primary target for the action of environmental pollutants on fish.…”

“…The first studies showed that the European eels (Anguilla anguilla ) chronically exposed to environmental cocaine concentrations bioaccumulate cocaine in their tissues (Capaldo et al . ) and undergo endocrine alterations (Gay et al . ).…”