Determination of selected antibiotics in the Istanbul strait sediments by solid-phase extraction and high performance liquid chromatography

Pollution and toxicity of sediment in potential dredging sites of the Marmara Sea, Turkey

This study aims to assess the impact of the sediment in the potential dredging areas of the Marmara Sea. To that aim, sediments were analyzed for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and heavy metals, sources were discussed, and toxicity tests were applied. For assessment, lower and upper limits of Turkish draft regulation (L_TR, U_TR) and UNEP-MAP's guidance document (LCT, UCT), and effects range low and median (ERL, ERM) were used. Total concentrations were found between 562 and 8643 µg kg^-1 for PAHs, 4-36 µg kg^-1 for PCBs, and 14-190 µg kg^-1 for OCPs. The highest ∑PAH concentrations were measured in Golden Horn, and none of the PAH compounds was above ERM. ERL and UCT were exceeded in İstinye and Golden Horn stations. The highest ∑PCBs and ∑OCPs levels were determined in İzmit Bay (IB). ΣPCBs in IB were higher than ERL and L_TR, while ΣDDT were found above ERM and UCT. High concentrations of chromium (∼190 mg kg^-1) and copper (∼180 mg kg^-1) in Golden Horn and mercury in IB (∼4 mg kg^-1) were detected. The highest toxicities were observed in İstinye and İzmit Bay. According to the regulations, none of the sediments can be dumped.

Pharmaceutical residues are widespread in Baltic Sea coastal and offshore waters - Screening for pharmaceuticals and modelling of environmental concentrations of carbamazepine

The consumption of pharmaceuticals worldwide coupled with modest removal efficiencies of sewage treatment plants have resulted in the presence of pharmaceuticals in aquatic systems globally. In this study, we investigated the environmental concentrations of a selection of 93 pharmaceuticals in 43 locations in the Baltic Sea and Skagerrak. The Baltic Sea is vulnerable to anthropogenic activities due to a long turnover time and a sensitive ecosystem in the brackish water. Thirty-nine of 93 pharmaceuticals were detected in at least one sample, with concentrations ranging between 0.01 and 80 ng/L. One of the pharmaceuticals investigated, the anti-epileptic drug carbamazepine, was widespread in coastal and offshore seawaters (present in 37 of 43 samples). In order to predict concentrations of pharmaceuticals in the sub-basins of the Baltic Sea, a mass balance-based grey box model was set up and the persistent, widely used carbamazepine was selected as the model substance. The model was based on hydrological and meteorological sub-basin characteristics, removal data from smaller watersheds and wastewater treatment plants, and statistics relating to population, consumption and excretion rate of carbamazepine in humans. The grey box model predicted average environmental concentrations of carbamazepine in sub-basins with no significant difference from the measured concentrations, amounting to 0.57-3.2 ng/L depending on sub-basin location. In the Baltic Sea, the removal rate of carbamazepine in seawater was estimated to be 6.2 10^-9 s^-1 based on a calculated half-life time of 3.5 years at 10 °C, which demonstrates the long response time of the environment to measures phasing out persistent or slowly degradable substances such as carbamazepine. Sampling, analysis and grey box modelling were all valuable in describing the presence and removal of carbamazepine in the Baltic Sea.

Distribution, sources, and ecological risk assessment of quinotone antibiotics in the surface sediments from Jiaozhou Bay wetland, China

The distribution, sources, and risk assessment of eight quinotone antibiotics (QNs) in the surface sediments from the wetland in Jiaozhou Bay were investigated. The results showed that QNs were detected in all samples, and the total concentrations of QNs in the sediments ranged from 0.276 to 5.229ng/g. The highest concentration occurred at the entrance to the Yang River wetland. Principal component analysis suggested that the QNs mainly originated from sewage discharges from hospitals, human and aquaculture industries. Risk assessment, based on risk quotients, indicated the current ofloxacin level might be a medium risk level, while other QNs were all low risk. Nevertheless, there should still be concerns due to high consumption of QNs by human beings, animals, and aquatic organisms in the wetland. This investigation provides baseline data that the government can use as a reference guide to control QNs residues in Jiaozhou Bay wetland.

Tracking aquaculture-derived fluoroquinolones in a mangrove wetland, South China

Aquaculture in mangrove wetlands has been developed rapidly, causing various environmental problems (e.g., antibiotic residue). In the present study, the levels and distributions of a well-known class of antibiotics (fluoroquinolones; FQs), including norfloxacin (NOR), ciprofloxacin (CIP), and enrofloxacin (ENR), were examined in sediment and mangrove plant (Aegiceras corniculatum) from a mangrove wetland in the Zhanjiang Mangrove National Nature Reserve, South China. NOR and CIP were detected in all sediment samples, with concentrations ranging from 4.3 to 64.2 ng/g and from 7.62 to 68.5 ng/g on a basis of dry weight (dw), respectively, whereas ENR was found with relatively lower frequency (<78%) and lower concentrations (<19.3 ng/g). Sediments in mangrove rhizosphere area contained considerably higher concentrations of all FQs (except for ENR). FQs were largely varied in mangrove plant tissues; NOR and ENR were not detected in leaf and root samples, respectively. CIP featured an increasing tendency from the root to the upper parts of plants, whereas a decreasing trend was found for NOR. Three bioconcentration factors (BCF_s) of FQs, including BCFs for roots (BCF_r), branches (BCF_b), and leaves (BCF_l) were calculated, and most of them exceeded 1. Especially for NOR, its BCF_r can reach up to 9.9, indicating that Aegiceras corniculatum has a strong ability to accumulate FQs from sediment and/or surrounding environment. For NOR and CIP, strong positive relationships were observed between BCF_r and concentrations in root, but no significant correlations were observed between BCF_r and root lipid of mangrove plant. More studies are needed to investigate the uptake mechanism of antibiotics in mangrove plants.

Occurrence and distribution of the environmental pollutant antibiotics in Gaoqiao mangrove area, China

Occurrence and distribution of 15 antibiotics belonging to families of sulfonamides, fluoroquinolones, tetracyclines and chloramphenicols were investigated in water and sediment in Gaoqiao mangrove area, China, using LC-MS-MS. The influence of tidal level and mangrove vegetation on antibiotic residues were examined. The levels of antibiotics were found to be ranged from 0.15 to 198 ng L(-1) in water and from 0.08 to 849 μg kg(-1) in sediment. No significant difference in concentrations of 15 different antibiotics from water and sediment samples was observed among the high, middle and low intertidal channel. The residues of SMZ, SMTZ, OFL, NOR, ENR, OXY and FLO were significantly higher in Aegiceras corniculatum assemblage than in Avicennia marina assemblage. Although no significant difference in tested antibiotics was found between the surface and bottom sediment, mangrove vegetation can to some extent reduce the accumulation for SMZ, SMTZ, OFL, NOR, CIP, OXY and TET in sediments relative to corresponding bare mudflats, implying that the environmental pollution from antibiotics may be mitigated by mangrove vegetation. Principal components analysis revealed that the terrestrial input and different habitats directly influenced the occurrence and distribution of antibiotics.

Fluoroquinolone antibiotics: an emerging class of environmental micropollutants

The aim of this review paper is to provide a comprehensive overview of different chemical and environmental aspects concerning fluoroquinolone antibiotics as emerging contaminants. A literature survey has been performed based on 204 papers from 1998 to mid-2013, resulting in a dataset consisting out of 4100 data points related to physical-chemical properties, environmental occurrence, removal efficiencies, and ecotoxicological data. In a first part, an overview is given on relevant physical-chemical parameters to better understand the behavior of fluoroquinolones during wastewater treatment and in the environment. Secondly, the route of these antibiotics after their application in both human and veterinary surroundings is discussed. Thirdly, the occurrence of fluoroquinolone residues is discussed for different environmental matrices. The final part of this review provides a tentative risk assessment of fluoroquinolone compounds and their transformation products in surface waters by means of hazard quotients. Overall, this review shows that fluoroquinolone antibiotics have a wide spread use and that their behavior during wastewater treatment is complex with an incomplete removal. As a result, it is observed that these biorecalcitrant compounds are present in different environmental matrices at potentially hazardous concentrations for the aquatic environment. The latter calls for actions on both the consumption as well as the wastewater treatment aspect to diminish the discharge of these biological active compounds.