Antibiotics are an increasing focus of interest due to their high detection frequency in the environment. However, their presence in water bodies is not regulated by environmental policies. This field study investigates, for the first time, the occurrence, behavior and fate of a selection of 53 antibiotics, including up to 10 chemical groups, in an alluvial aquifer originated from manure application in an agricultural region using hydrogeological, hydrochemical and isotopic approaches. Up to 11 antibiotics were found in groundwater corresponding to 4 different chemical groups: fluoroquinolones, macrolides, quinolones and sulfonamides. In surface water, only 5 different antibiotics from 2 chemical groups: fluoroquinolones and sulfonamides, were quantified. The most frequent antibiotics were sulfamethoxazole and ciprofloxacin. Concentrations of antibiotics were in the order of ng/L, with maximum concentrations of 300ng/L in groundwater. Hydrochemistry and isotopic data and geostatistics confirmed the spatial trend observed for nitrates, where nitrate concentrations tend to be higher in the margin areas of the study area, and lower concentrations are found nearby the river. On the other hand, no clear continuous spatial concentration trend of antibiotics was observed in the aquifer, supported by the short spatial correlation found in the variograms. This indicates that the physical-chemical properties and processes of each antibiotic (mainly, sorption and degradation), and other environmental issues, such as a patchy diffuse input and the manure antibiotic content itself, play an important role in their spatial distribution in groundwater. A discussion on the estimation of the antibiotic sorption parameter reveals the difficulties of describing such phenomena. Furthermore, retardation factors will extend over several orders of magnitude, which highly affects the movement of individual antibiotics within the aquifer. To summarize, this study points out the difficulties associated with antibiotic research in groundwater in order to define water resources quality management strategies and environmental regulations.
Trace elements appear in natural waters as a result of rock weathering and human activities. Their occurrence is governed by a complex set of geochemical conditions which finally may induce trace element concentrations above health standards. In regional, large-scale aquifers, their presence is representative of the hydrogeological setting of the overall flow path from the recharge zone to the sampling well. In this study, we analyze hydrochemical, including major components and trace elements (Al, As, B, Ba, Cd, Co, Cr, Cu, Hg, Mn, Ni, Sb, Sn, Sr, Pb, Zn), and stable isotopic data from exploitation wells in the Empordà basin (NE Spain). Our goal is to explore the hydrogeological meaning of trace elements as a means to contribute to the understanding of the regional flow dynamics as an initial step to face trace element pollution events. Groundwater data is hence described in the context of each aquifer relating the major hydrochemical facies with their accompanying trace elements. Results point out some expected geochemical relationships as well as some trace element associations that cannot be envisaged from the usual incomplete lithological information of the aquifer. Multivariate statistical analysis, as PCA, provides complementary information about geochemical processes (loadings) and regional occurrence (scores). Such statistical information can be taken as indicative of potential health hazard associated to trace element in groundwater. From a management perspective, such analysis points out which elements should a priori be considered for analysis according to the geological formation that holds the water supply wellThis study has been developed under the Spanish Government Project CGL2011-29975-c04-04 and continued under Project CGL2014-57215-C4-2-R and the University of Girona fund MPCUdG2016/06
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.