22 research outputs found
5-Fluorouracil and Its Prodrug Capecitabine: Occurrence, Fate and Effects in the Environment
In this chapter, we examine the available literature on the cycling and
effects of 5-flourouracil (5-FU) and capecitabine (CAP) residues in the aqueous
environment. The aim is to understand better their environmental occurrence, fate
and potential toxic effects. Physicochemical properties of 5-FU and CAP suggest that
they are more likely to remain in aqueous environment than adsorbed to solid particles.
Detectable levels have been reported in hospital effluents (< 122 μg/L) and in
municipal wastewaters (< 280 ng/L), but rarely in surface waters (only 5-FU in one
study: < 160 ng/L). Among different water treatments available, the most promising
for removing 5-FU and CAP are the advanced oxidation processes (AOPs). So far,
indirect photolysis has been most widely applied and is capable of almost completely
removing both compounds (to < LOD) and in some cases resulting in complete
mineralization. However, these treatments have been mostly tested in MilliQ or
potable water and their suitability for complex matrices like wastewaters is questionable
and biodegradation is still treatment of choice for these matrices. In other studies,
a variety of transformation products has been identified adding to the overall environmental
burden. Toxicity tests on single parent compounds have shown that they may
have effects above the concentrations of environmental relevance. The studies of
complex mixtures of parent compounds highlight that the actual ecological risk
posed by mixtures of these compounds is difficult to evaluate. Overall, the main
finding from this review is that a real need exists for further studies on the chemical
and toxicological effects of environmental mixtures of cytotoxic compounds
Single and simultaneous adsorption of three sulfonamides in agricultural soils: Effects of pH and organic matter content
Veterinary antibiotics reaching the environment have become a matter of global concern, since they can cause
serious negative impacts on human and ecological health. Therefore, a deep understanding of their behavior
and fate once they reach the soil environment is of utmost importance to design and implement appropriate
measures that could reduce their potential risks. With this aim, batch-type experiments were carried out to
study competitive adsorption and desorption for three sulfonamide antibiotics (sulfadiazine –SDZ-, sulfamethazine
–SMT-, and sulfachloropyridazine –SCP-) in six crop soils presenting different characteristics. The results obtained
showed that sulfonamides have a low retention in soils, with average adsorption percentages of 40% for
SDZ, 44% for SMT and 54% for SCP, and with desorption percentages up to 36% for SDZ and SCP and up to 29%
for SMT. The retention of sulfonamides was strongly influenced by the soil organic carbon content (SOC), with
higher adsorption and less desorption associated to higher SOC contents. In addition, the hydrophobicity of sulfonamides
also had an influence, as higher hydrophobicity resulted in higher affinity for soils, showing the affinity
sequences: SDZ ~ SMT bSCP in acid soils, and SDZ ~ SCP bSMT in neutral soils. The results obtained in the
ternary systems were very similar to those found in simple systems, indicating the absence of substantial competition
for adsorption sites among the three sulfonamides. Despite the low competition among them, these antibiotics
have high mobility in soils and, therefore, they imply a significant risk of contamination ofwater bodies,
as well as of entering the food chain, generating serious hazards for human and environmental health. Therefore,
fertilization of soilswith sulfonamide polluted manures should be controlled, implementing newmeasurements
for the pretreatment of manures before their application, thus contributing to a reduction of potential risks.Ministerio de Economía y Competitividad
Fondos FEDERS