Many pharmaceutical residues (such as carbamazepine, ibuprofen, gemfibrozil, naproxen, diclofenac, ketoprofen and estrone) have been found in rivers, including the River Tiber (Rome, Italy). Along its urban stretch, the anti-inflammatory drug Naproxen is one of the most commonly found in high concentration, ranging from 200 to 1000 ng/L depending on the sampling point (e.g. upstream or downstream of the effluents of the wastewater treatment plants around Rome). In order to assess the ecosystem service consisting of natural attenuation of this drug in the river, the capability of the autochthonous microbial community to biodegrade Naproxen was evaluated. For this purpose, we conducted microcosm experiments using undisturbed river water samples collected in two different seasons (Spring and Autumn). The first experiment consisted of Microbiologically Active Water (MAW) microcosms (50 mL) treated with 100 µg/L of Naproxen. The biotic degradation was evaluated comparing the MAW microcosms with the microcosms containing previously sterilized river water. The second experiment was performed in the same conditions as the first one; moreover, some additional microcosms were used in order to evaluate Naproxen degradation in the co-presence of another pharmaceutical, the lipid regulator Gemfibrozil. The degradation of Naproxen occurred in all the MAW microcosms, showing a DT50 of about 20 days. However, the co-presence of Gemfibrozil initially affected Naproxen degradation by lengthening the degradation lag phase. The bacterial abundance decreased immediately after the treatment, but this toxic effect was transient. The analysis of the bacterial community structure by the Fluorescence In Situ Hybridization method (FISH) made it possible to highlight the increase of some bacterial groups such as Gamma- and Alpha-Proteobacteria near the time of the DT50s, suggesting their active role in the drug degradation. On the contrary, in the sterile microcosms no decrease of Naproxen concentration was observed during the experimental period. The overall results showed that the autochthonous river microbial community had a natural ability to remediate pharmaceutical contamination. The fact that Naproxen residual concentrations are commonly found in the river can be ascribed not to its intrinsic persistence (after 35-40 days Naproxen was completely degraded in the microcosms), but to its pseudo-persistence due to the spread in its use among the human population.
Pharmaceutical remediation as an ecosystem service provided by natural microbial communities In: Building a Better future: responsible innovation and environmental protection
Grenni P;Patrolecco L;Ademollo N;Barra Caracciolo A
2013
Abstract
Many pharmaceutical residues (such as carbamazepine, ibuprofen, gemfibrozil, naproxen, diclofenac, ketoprofen and estrone) have been found in rivers, including the River Tiber (Rome, Italy). Along its urban stretch, the anti-inflammatory drug Naproxen is one of the most commonly found in high concentration, ranging from 200 to 1000 ng/L depending on the sampling point (e.g. upstream or downstream of the effluents of the wastewater treatment plants around Rome). In order to assess the ecosystem service consisting of natural attenuation of this drug in the river, the capability of the autochthonous microbial community to biodegrade Naproxen was evaluated. For this purpose, we conducted microcosm experiments using undisturbed river water samples collected in two different seasons (Spring and Autumn). The first experiment consisted of Microbiologically Active Water (MAW) microcosms (50 mL) treated with 100 µg/L of Naproxen. The biotic degradation was evaluated comparing the MAW microcosms with the microcosms containing previously sterilized river water. The second experiment was performed in the same conditions as the first one; moreover, some additional microcosms were used in order to evaluate Naproxen degradation in the co-presence of another pharmaceutical, the lipid regulator Gemfibrozil. The degradation of Naproxen occurred in all the MAW microcosms, showing a DT50 of about 20 days. However, the co-presence of Gemfibrozil initially affected Naproxen degradation by lengthening the degradation lag phase. The bacterial abundance decreased immediately after the treatment, but this toxic effect was transient. The analysis of the bacterial community structure by the Fluorescence In Situ Hybridization method (FISH) made it possible to highlight the increase of some bacterial groups such as Gamma- and Alpha-Proteobacteria near the time of the DT50s, suggesting their active role in the drug degradation. On the contrary, in the sterile microcosms no decrease of Naproxen concentration was observed during the experimental period. The overall results showed that the autochthonous river microbial community had a natural ability to remediate pharmaceutical contamination. The fact that Naproxen residual concentrations are commonly found in the river can be ascribed not to its intrinsic persistence (after 35-40 days Naproxen was completely degraded in the microcosms), but to its pseudo-persistence due to the spread in its use among the human population.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
