Paola Bottoni

Pharmaceuticals as priority water contaminants

Pharmaceuticals and their metabolites can reach water bodies through sewage systems, industrial discharges, effluents from sewage treatment plants (STPs), aquaculture, and livestock farming. Pharmaceuticals include a hundred substances which are very different as regards chemical–physical properties and environmental behavior, although they may have strong biochemical activities. At present, pharmaceuticals can reach water concentrations of ng L−1 to µg L−1 and some are considered ubiquitous. Nevertheless, their presence in the aquatic environment and impact on aquatic biota and on human health have not yet been studied adequately. Experimental evidence indicates that pharmaceuticals may cause harmful effects, such as morphological, metabolic and sex alterations on aquatic species, induction of antibiotic resistance in aquatic pathogenic microorganisms, and disruption of biodegradation activities in STPs. Risk assessment studies and evaluations are in progress. Yet, the available scientific data are consistent with the introduction of some pharmaceutical indicators in extensive water monitoring to better define their actual impact on aquatic organisms and humans. Under these perspectives, the inclusion of emerging pharmaceuticals in the revision of EU List of Priority Substances under the Water Framework Directive 2000/60/EC should be implemented as well as the definition of respective environmental quality standards.

Fluorescence in situ hybridization in soil and water ecosystems: a useful method for studying the effect of xenobiotics on bacterial community structure.

The ability of soil and groundwater ecosystems to recover from chemical contamination is primarily dependent on the presence of a microbial community which has the ability to remove it. Nevertheless, there has been a little research into these communities because it is strictly dependent on methods capable of identifying and characterizing their community structure and functioning. The use of molecular methods makes it possible to overcome this kind of identification limitation. In this work, we applied the fluorescence in situ hybridization (FISH) method to different samples, such as soil and groundwater contaminated with s-triazine herbicides (simazine or terbuthylazine) and surface water treated with the pharmaceutical oseltamivir carboxylate (Tamiflu). We compared the bacterial community structure in the presence/absence of these xenobiotics. The use of 16S rRNA-targeted oligonucleotide probes, designed specifically for the main phylogenetic levels (Archaea, Bacteria, α-, β-, γ-, ε-subdivision of Proteobacteria, Planctomycetes, Gram-positive bacteria with a high or low DNA G + C content, Cytophaga-Flavobacter-Bacteroides phylum, and sulfate-reducing bacteria), and a DAPI stain made it possible to assess the structure of the bacterial community and its changes in the presence of these xenobiotics in all the ecosystems studied.

Detection and quantification of residues and metabolites of medicinal products in environmental compartments, food commodities and workplaces. A review

The toxicological assessment of medicinal products (MPs) and their residues and metabolites in the environment have become a challenging task worldwide. The contamination of environmental compartments, biota, workplace, foodstuff and feedstuff by residues and metabolites of these substances poses a risk to human health which is still far from being fully understood. On the other hand, existing analytical methods not always possess sufficient detection power to quantify residues of MPs at very low concentrations. This review sets forth some of the most significant contributions made in this field over the past decade with a special focus on novel fit-for-purpose analytical approaches for the detection, identification and quantification of these pollutants and the assessment of their noxious potential for human beings and the environment.

Microbial degradation of two carbamate insecticides and their main metabolites in soil

Degradation studies in soil of the insecticides aldicarb and carbofuran and their metabolites (aldicarb sulfoxide, aldicarb sulfone; 3-ketocarbofuran and 3-hydroxycarbofuran) were carried out using laboratory systems under controlled conditions (temperature, water content, light). The insecticides were added to soil samples and subsamples of the soil were analyzed at different times to assess both the bacterial abundance and the concentration of the different chemicals. The epifluorescence direct count method was applied to the subsamples to estimate microorganism numbers (N/g soil). Untreated samples of soil were used as controls for evaluating the effects of the application of the insecticides on microbial abundance. Subsamples treated with the pesticides were analyzed using HPLC and the DT 50 s of the different compounds studied were calculated. The DT 50 values show that neither the parent compounds nor the transformation products have a high persistence in soil and there is a general increase in the concentration of microorganisms as the pesticides diminish.