Global issues in setting legal limits on soil metal contamination: A case study of Chile.

The establishment of legal limits for soil contamination with trace elements is a global issue that has not yet been resolved. However, the resolution of any global problem begins at the national level. In this vein, we present the case of Chile, the world's leading copper producer, where soil contamination by trace elements in mining areas has been severe. We evaluated the magnitude of the ecological and human health risks from exposure to arsenic (As), copper (Cu), zinc (Zn), and lead (Pb) in soils of the La Ligua and Petorca basins, two important mining areas in Chile. Contrary to what might be expected in soils affected by Cu mining activities, As was identified as the most hazardous element in the studied soils, both in terms of ecological and human health risks. On the other hand, Chile does not currently have specific legislation establishing legal limits on soil contamination with trace elements. Since Chile is geochemically similar to New Zealand, Mexico, and Italy, we used the limits of these three countries as benchmarks. We determined the background concentrations of As, Cu, Zn, and Pb in the soils of the two river basins under study and found that they tend to exceed the limits established by foreign laws. We also found that the differences in background elemental concentrations in the studied soils were primarily due to the varied lithology of soil-forming rocks. This means that absolute "one-limit-fits-all" values of element concentrations may not be adequate to regulate the level of soil contamination in areas affected by mining. As a fundamental first step, it is necessary to establish background soil concentrations of trace elements in each river basin in Chile. It is clear that Chile urgently needs to move from rubber-stamping foreign laws to the development of national legislation on soil metal contamination.

Advanced determination of the spatial gradient of human health risk and ecological risk from exposure to As, Cu, Pb, and Zn in soils near the Ventanas Industrial Complex (Puchuncaví, Chile).

The townships of Puchuncaví and Quintero, on the coast of central Chile, have soils contaminated by atmospheric deposition of sulfur dioxide and trace elements from the nearby Ventanas Industrial Complex. The purpose of this study was to evaluate potential human health and ecological risks, by determining the spatial distribution of soil total concentrations arsenic (As), copper (Cu), lead (Pb), and zinc (Zn) in these townships. Total concentrations of these elements were determined in 245 topsoil samples, used to generate continuous distribution maps. The background concentrations of Cu, As, Pb, and Zn in the studied soils were 100, 16, 35, and 122 mg kg-1, respectively. The concentrations of Cu, As, and Pb were positively correlated with each other, suggesting that their source is the Ventanas copper smelter. On the other hand, correlations for Zn were weaker than for other trace elements, suggesting low impact of the Ventanas copper smelter on spatial distribution of Zn. Indeed, only 6% of the study area exhibited Zn concentrations above the background level. In contrast, 77, 32 and 35% of the study area presented Cu, As, and Pb concentrations, respectively, above the background level. The carcinogenic risk due to exposure to As was above the threshold value of 10-04 in the population of young children (1-5 years old) on 27% of the study area. These risk values are classified as unacceptable, which require specific intervention by the Chilean government. Based on the estimated concentrations of exchangeable Cu, 10, 15, and 75% of the study area exhibited high, medium, and low phytotoxicity risk, respectively.

Water-soluble Ru(II)-anethole compounds with promising cytotoxicity toward the human gastric cancer cell line AGS.

AIMS: Ruthenium-based compounds exhibit critical biochemical properties making them suitable for diverse pharmacological applications. The aim of this work was to study the anticancer effects of three ruthenium complexes on a human gastric cancer cell line. MAIN METHODS: We synthetized three [Ru(η6-anethole)(en)X]PF6 complexes, where (en) is ethylenediamine and X is Cl (1), Br (2) or I (3), which were then evaluated by MTT assay, RT-qPCR and flow cytometry on the human gastric cancer cell line AGS. KEY FINDINGS: Compound 3 exhibited the highest cytotoxicity (IC50 = 11.27 ±â€¯1.08 µM) of the series, with an activity almost three-fold more potent than the commercial drug cisplatin, and also revealed a 4.5-fold less potent cytotoxicity in the human normal gastric cell line GES-1. The exchange of the halogen (Cl, Br or I) on the organometallic compound slightly alters its solubility in PBS and lipophilicity (expressed as Log P). Studies of gene expression revealed that compound 3 induces a significant overexpression of the pro-apoptotic genes Caspase-3, PUMA and DIABLO in the gastric cancer cell line AGS after 6 h. In contrast, only PUMA was significantly overexpressed in the normal gastric cell line GES-1. Compound 3 induced the activation of multiple caspases in AGS cells: a sign of apoptosis. Characterization via single-crystal X-ray diffraction for compound 3 confirmed the key structural features for this type of organometallic complexes. SIGNIFICANCE: Our data suggests that compound 3 may be an interesting anticancer molecule for the treatment of gastric cancer.

Chromatographic approaches for determination of low-molecular mass aldehydes in bio-oil.

HPLC-UV and GC/MS determination of aldehydes in bio-oil were evaluated. HPLC-UV preceded by derivatization with 2,4-dinitrophenylhydrazine allows separation and detection of bio-oil aldehydes, but the derivatization affected the bio-oil stability reducing their quantitative applicability. GC/MS determination of aldehydes was reached by derivatization with o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride. Two approaches for this reaction were evaluated. The first: "in solution derivatization and head space extraction" and the second: "on fiber derivatization SPME", the latter through an automatic procedure. Both sample treatments allows the quantification of most important aliphatic aldehydes in bio-oil, being the SPME approach more efficient. The aldehyde concentrations in bio-oil were ~2% formaldehyde, ~!0.1% acetaldehyde and ~0.05% propionaldehyde.

High performance thin layer chromatography determination of cellobiosan and levoglucosan in bio-oil obtained by fast pyrolysis of sawdust.

In this work, high performance thin layer liquid chromatography (HTPLC) is applied to the determination of sugars in fast pyrolysis liquids (bio-oil) and fractions thereof. The proposed procedure allows the separation of anhydrosugar levoglucosan and cellobiosan, as well as glucose, arabinose, xylose and cellobiose. Pre-treatment and derivatization of samples are not necessary and volatile compounds present in bio-oil do not interfere with sugar analysis. The detrimental effect of the complex bio-oil matrix on columns and detector lifetime is avoided by using disposable HTPLC plates. Prior screening of glucose, present especially in aged and aqueous bio-oil fractions, is required to quantify cellobiosan without interference. Concentrations of levoglucosan and cellobiosan in bio-oil samples obtained from Pinus radiata sawdust were ranged between 1.27-2.26% and 0.98-1.96% respectively, while a bio-oil sample obtained from native wood contained a higher levoglucosan concentration.

Alternatives for sample pre-treatment and HPLC determination of Ochratoxin A in red wine using fluorescence detection.

Ochratoxin A is a mycotoxin widely studied due to its nephrotoxic, immunotoxic, teratogenic and carcinogenic effects. The European Commission has fixed maximum limits for Ochratoxin A in wines and in other foods. In order to determine Ochratoxin A levels in red wine, the present paper contrasts and discusses the results of a systematic study of analytical parameters for sample pre-treatment using different immunoaffinity cartridges as well as C-18 cartridges with three solvent combinations. The direct injection of wine into two types of C-18 chromatographic columns (conventional packed column and monolithic column) is evaluated as screening method. In all cases, the analysis was carried out using HPLC with fluorescence detection. The results show statistical differences when 3 types of immunoaffinity columns were used, while higher recoveries were obtained for C-18 cartridges using acetonitrile as extraction solvent. Repeatability and accuracy of immunoaffinity and C-18 sample pre-treatment were statistically comparable (alpha=0.05). Their sensitivity was also comparable, although more favorable detection limits were obtained using the immunoaffinity treatment (0.01 microg L(-1)) in comparison with C-18 treatment (0.09 microg L(-1)). Considering the maximal allowed concentration of Ochratoxin A in wine (2.00 microg L(-1)), both methods are suitable for its determination in wine. Both methods were applied to determine this toxin in 154 wine samples, and the quantitative results demonstrated statistic comparability (alpha=0.05). These results were also confirmed from the qualitative point of view using a GC-MS method. To find an easy screening method, based on a recent publication, a monolithic HPLC column and 2 conventional packed columns were tested for Ochratoxin A determination in real wine samples by direct injection, without previous clean-up. The results show that this procedure is not useful at the concentration levels usually found in wine and although shorter time is required when using the monolithic columns even with the chromatographic analysis. Finally, based on the results, it was concluded that the combination of C-18 cartridges with conventional particle packed columns and HPLC-FLD is the most appropriate alternative for Ochratoxin A analysis in wine. Indeed, considering cost, sensitivity and selectivity, this method can be used in broad prospective programs.

Butyltin compounds and their relation with organic matter in marine sediments from San Vicente Bay-Chile.

Tributyltin and its degradation products, mono-and dibutyltin have been determined in sediments collected in some representative sites in San Vicente Bay, Chile. The organic matter contents of sediments and water collected simultaneously from the same sampling sites were also determined. High levels of total organic carbon were found in sediments, especially in those from the northern part of the bay (1.80-8.87%). Good correlations were found between total organic carbon and the oxidizable and refractory carbon fractions. Among the butyltin species determined, TBT presented the highest levels, ranging from 14 to 1,560 ng Sn g(-1) dry weight. Concentration ratios of TBT to DBT ranged between 1.33 and 3.10, showing a high degree of contamination in sediments of this Chilean bay. All data obtained were analysed by the chemometric method of principal components analysis. A strong correlation was found between TBT and DBT concentrations in sediments, the different organic matter contents in sediments and water. In marine organisms only TBT was detected, containing the filterer organism Semele solida higher level than Perumytilus purpuratus and Pyura chilensis (220, 150 and 120 ng Sn g(-1) dry weight, respectively). For the alga Rodoficea iridae the TBT concentration was 60 ng Sn g(-1) dw. Comparatively, these values are higher than those reported for the same kind of marine organisms worldwide. The different samples from San Vicente Bay were found to be contaminated by TBT. This contamination can be attributed to the different anthropogenic activities taking place in the bay.