Daniel A. Wunderlin

Use of water quality indices to verify the impact of Córdoba City (Argentina) on Suquía River.

Abstract We verified the usefulness of water quality indices (WQI) to assess the water quality from multiple measured parameters, and to evaluate spatial and temporal changes. Measured parameters include many of those recommended by the GEMS/Water UNEP program. Two WQI (subjective and objective—WQIsub and WQIobj) take into consideration 20 parameters. Another index (minimal—WQImin) was developed considering only three parameters: turbidity, dissolved oxygen, and either conductivity or dissolved solids. WQIsub tends to overestimate the pollution due to the use of a subjective constant, which is not necessarily correlated with the measured parameters. WQImin shows a similar trend to WQIsub and WQIobj at a lower analytical cost; however, it should be combined with WQIobj to corroborate the results. The use of WQI could be of particular interest for developing countries, because they provide cost-effective water quality assessment as well as the possibility of evaluating trends. As a case study, we report on the use of WQI to evaluate spatial and seasonal changes in the water quality from the Suquia River in Cordoba City (Argentina) and nearby locations. The city urban activity produces a serious and negative effect on the water quality; this is particularly severe in locations following the city sewage discharge. The dry season shows the worst water quality.

Oxidative stress responses in different organs of Jenynsia multidentata exposed to endosulfan.

We evaluate antioxidant responses of Jenynsia multidentata experimentally exposed to sublethal concentrations of endosulfan (EDS). The main goal was to determine differences in the response between different organs to assess which one was more severely affected. Thus, we exposed females of J. multidentata to EDS during 24h, measuring the activity of GST, GR, GPx, CAT and LPO in brain, gills, liver, intestine and muscle of both exposed fish and controls. GST activity was inhibited in gills, liver, intestine and muscle of exposed fish but was induced in brain. GR and GPx activities were increased in brain and gills at 0.014 and 0.288 microg L(-1), respectively. GPx activity was inhibited in liver and muscle at all studied concentrations whereas inhibition was observed in the intestine above 0.288 microg L(-1). Exposure to 1.4 microg L(-1) EDS caused CAT inhibition and increase of LPO levels in liver. LPO was also increased in brain at almost all concentrations tested. We find that the brain was the most sensitive organ to oxidative damage. Thus, J. multidentata could be used as a suitable bioindicator of exposure to EDS measuring activities of antioxidant enzymes in brain and liver as biomarkers.

Fingerprints for Main Varieties of Argentinean Wines: Terroir Differentiation by Inorganic, Organic, and Stable Isotopic Analyses Coupled to Chemometrics

Our main goal was to investigate if robust chemical fingerprints could be developed for three Argentinean red wines based on organic, inorganic, and isotopic patterns, in relation to the regional soil composition. Soils and wines from three regions (Mendoza, San Juan, and Córdoba) and three varieties (Cabernet Sauvignon, Malbec, and Syrah) were collected. The phenolic profile was determined by HPLC-MS/MS and multielemental composition by ICP-MS; (87)Sr/(86)Sr and δ(13)C were determined by TIMS and IRMS, respectively. Chemometrics allowed robust differentiation between regions, wine varieties, and the same variety from different regions. Among phenolic compounds, resveratrol concentration was the most useful marker for wine differentiation, whereas Mg, K/Rb, Ca/Sr, and (87)Sr/(86)Sr were the main inorganic and isotopic parameters selected. Generalized Procrustes analysis (GPA) using two studied matrices (wine and soil) shows consensus between them and clear differences between studied areas. Finally, we applied a canonical correlation analysis, demonstrating significant correlation (r = 0.99; p < 0.001) between soil and wine composition. To our knowledge this is the first report combining independent variables, constructing a fingerprint including elemental composition, isotopic, and polyphenol patterns to differentiate wines, matching part of this fingerprint with the soil provenance.

Determination of priority pesticides in water samples combining SPE and SPME coupled to GC-MS. A case study: Suquía River basin (Argentina).

This study reports a combined method using solid phase extraction (SPE), followed by solid phase microextraction (SPME) to concentrate different pesticides, including chlorinated, organophosphorus, triazines, pyretroids and chloroacetamides, present at trace levels in water samples. Identification and quantification was carried out by gas chromatography coupled to Mass Spectrometry (GC-MS). The optimized methodology showed LOQs at ng L(-1) levels (ranging 0.2-3.5 ng L(-1)) in addition to acceptable precision and robustness (recoveries ranged 63-104%, RSD from 4% to 23%), presenting a novel method to reach trace levels, similar to that obtainable using EC detector, with structural confirmation by MS during the analysis of a wide range of environmental pollutants. This method was applied to the study of temporal and spatial distribution of pesticides in the Suquía River basin (Córdoba-Argentina). As expected, highest levels of agrochemicals were observed in areas with intensive agricultural practices, being atrazine (max.=433.9 ng L(-1)), alpha-cypermetrine (max.=121.7 ng L(-1)) and endosulfan sulfate (max.=106.7 ng L(-1)) predominant. In urban areas, the prevalent pesticide was alpha-cypermethrine. These results draw attention to the need of pesticide monitoring programs in rivers, considering both urban and rural sections.

Melatonin levels, determined by LC-ESI-MS/MS, fluctuate during the day/night cycle in Vitis vinifera cv Malbec: evidence of its antioxidant role in fruits.

Abstract:  The identification of melatonin in plants has inspired new investigations to understand its biological function and which endogenous and external factors control its levels in these organisms. Owing to the therapeutical and nutraceutical properties of melatonin, it should be important to develop reliable analytical methods for its quantification in vegetal matrices containing this indoleamine, such as grape and wine. The main objectives of the present study were to test whether melatonin levels fluctuate during the day in berry skins of Vitis vinifera L. cv Malbec, thereby possibly relating its abundance to its putative antioxidant function, to determine whether daylight reaching clusters negatively controls melatonin levels, and to evaluate whether total polyphenols and anthocyanins also change through a 24‐hr period. Grapes were harvested throughout the day/night to determine the moment when high levels of these components are present in grapes. The presence of melatonin in grapes was evaluated by high‐performance liquid chromatography/electrospray ionization tandem mass spectrometry. It is shown for the first time that melatonin levels fluctuate during the day/night cycle in plants grown under field conditions in a fruit organ of the species Vitis vinifera. We also determined that the diurnal decay of melatonin in berry skins is induced by sunlight, because covered bunches retained higher melatonin levels than exposed ones, thus explaining at least part of the basis of its daily fluctuation. Evidence of melatonin’s antioxidant role in grapes is also suggested by monitoring malondialdehyde levels during the day.

Multiple biomarkers responses in Prochilodus lineatus allowed assessing changes in the water quality of Salado River basin (Santa Fe, Argentina)

This field study assessed water quality of Salado River basin by using a set of biomarkers in the fish Prochilodus lineatus. Multiple biomarkers were measured, including morphological indexes (condition factor, liver somatic index), hematological (red and white blood cells) and biochemical (glucose, total protein and cholinesterase activity) parameters. Besides, detoxication and oxidative stress markers (antioxidant enzymes, lipid peroxidation) were measured in liver, gills and kidney. Despite water quality assessment did not show marked differences among sites, biomarkers responses indicate that fish are living under stressful environmental conditions. According to multivariate analysis glucose, glutathione S-transferase activity, lipid peroxidation levels and the count of white blood cells are key biomarkers to contribute to discrimination of sites. So, we suggest use those biomarkers in future monitoring of freshwater aquatic systems.

Endosulfan induces changes in spontaneous swimming activity and acetylcholinesterase activity of Jenynsia multidentata (Anablepidae, Cyprinodontiformes).

We assessed changes in spontaneous swimming activity and acetylcholinesterase (AchE) activity of Jenynsia multidentata exposed to Endosulfan (EDS). Females of J. multidentata were exposed to 0.072 and 1.4 microg L(-1) EDS. Average speed and movement percentage were recorded during 48 h. We also exposed females to EDS at five concentrations between 0.072 and 1.4 microg L(-1) during 24 h, and measured the AchE activity in brain and muscle. At 0.072 microg L(-1) EDS swimming motility decreased relative to the control group after 45 h, while at 1.4 microg L(-1) EDS swimming motility decreased after 24 h. AchE activity significantly decreased in muscle when J. multidentata were exposed to EDS above 0.072 microg L(-1), while no significant changes were observed in brain. Thus, changes in swimming activity and AchE activity in muscle are good biomarkers of exposure to EDS in J. multidentata.

Main flavonoids, DPPH activity, and metal content allow determination of the geographical origin of propolis from the Province of San Juan (Argentina).

The chemical characterization as well as the assessment of geographical origin of propolis from several areas of the Provincia de San Juan (Argentina) is reported. Chemical characterization of propolis was performed by measuring total phenolic (TP), total flavonoids (FL), free radical scavenging capacity (DPPH bleaching), and metal content in samples of six different districts. Methanolic propolis extracts (MEP) showed TP ranging from 25.7 to 39.3 g of gallic acid equivalents per 100 g of MEP, whereas flavonoids ranged from 6.6 to 13.3 g of quercetin equivalents per 100 g of MEP. Six main flavonoids were isolated and identified from the propolis samples, comprising the flavanones 7-hydroxy-8-methoxyflavanone (1), pinocembrin (2), and pinobanksin (3), the flavones chrysin (4) and tectochrysin (5), and the flavonol galangin (6). Compounds 1-6 were quantified by HPLC-PDA. Free radical scavenging activity, measured as percent DPPH bleaching, ranged from 46.6 to 89.5 at 10 mug/mL. Moreover, propolis samples presented high contents of Ca, K, Fe, Na, and Mg, but low amounts of Mn and Zn. Linear discriminant analysis affords eight descriptors, galangin, pinocembrin, pinobanksin, chrysin, tectochrysin, DPPH, K, and Na, allowing a clear distinction with 100% accuracy among different origins within the Provincia de San Juan. A direct relationship of DPPH free radical scavenging activity with TP or with compounds 1-6 was not found, showing the need of further evaluation on the origin of free radical activity in propolis samples.

Effects of microcystin-LR on the expression of P-glycoprotein in Jenynsia multidentata.

The multixenobiotic resistance phenomenon (MXR) related to the P-glycoprotein multidrug transporter protein (P-gp) has been identified and characterized in several aquatic organisms. In the present work, we prove the presence of a P-gp in liver, gills and brain of Jenynsia multidentata by Western Blot and RT-PCR. A 170 kDa protein has been found in liver and gills while in brain a approximately 80 kDa protein has been detected. The partial nucleotide sequence obtained in this autochthonous fish showed high similarity ranging from 83% to 92% with other fishes. In addition, P-gp expression in this fish was evaluated after time and dose-dependent exposures to the cyanotoxin microcystin-LR. Individuals were exposed to MC-LR at concentrations of 2, 5 and 10 microg L(-1) for 24h and for 6, 12 and 24h at 2 microg L(-1) MC-LR. Changes in P-gp expression were observed in liver, gills and brain. However, this response was tissue specific. Only in gills of J. multidentata P-gp expression, measured either by real-time RT-PCR or Western Blot, was significantly higher compared to controls at most tested times and doses. A 3-fold increase with respect to controls was found at 12h by RT-PCR and after 24h by Western Blot. In dose-dependent experiments the maximum P-gp expression was observed at 2 microg L(-1) MC-LR, measured by both RT-PCR and Western Blot. In the liver, P-gp protein levels were significantly increased after 24h of exposure, at every toxin dose tested. Thus, probably longer exposures would show also significant increases in this tissue. Considering these results we can propose that P-gp belongs to the defence system involved in the response to MC-LR in J. multidentata.

Copper-induced response of physiological parameters and antioxidant enzymes in the aquatic macrophyte Potamogeton pusillus.

Bioaccumulation and toxicity of copper was evaluated on Potamogeton pusillus L. The effect of copper (5-100 microg L(-1)) applied for several days was assessed by measuring changes in the chlorophylls, phaeophytins, malondialdehyde, electrical conductivity, glutathione peroxidase (GPX), glutathione reductase (GR) and guaiacol peroxidase (POD) activities. Plants accumulated copper with a maximum of 162 microg g(-1) dw after 7-days exposure at 100 microg L(-1), however most of the metal was accumulated after 1-day exposure. The toxic effect caused by Cu was evident by the reduction of photosynthetic pigments, increase of malondialdehyde and electrical conductivity. P. pusillus shows Cu-induced oxidative stress by modulating antioxidant enzymes like GPX, GR and POD. Antioxidant enzymes activity increased significantly after exposure to 40 microg L(-1) during 24 h, followed by a drop at longer times. Thus, P. pusillus is proposed as a good biomonitor for the assessment of metal pollution in aquatic ecosystems.