Geographical distribution of metals and metalloids along the estuary of the Oka River in the biosphere reserve of Urdaibai, Spain.

Sediments sampled at the estuary of the Oka River in the biosphere reserve of Urdaibai, Spain were analyzed for trace elements. Sediments were collected at 45 points of the estuary and the concentration of 14 elements was measured. The geoaccumulation indexes (Igeo), Normalized Average Weighted Concentrations (NAWC) and mean Effect Range-Median quotients (mERMq) were calculated. The results obtained were complementary and allowed intra- and inter-estuary comparison. According to the present findings, the estuary was classified as healthy, since the anthropogenic contribution of metals and metalloids was generally small. However, shipping and fishing activities at the ports of Bermeo and Mundaka and urban and industrial wastes from Gernika were regarded as the major pollution sources. Nevertheless, only slightly contaminated and toxic sediments, especially related to Ni and Cu, were found in the towns of Gernika and Mundaka.

Is there a direct relationship between stress biomarkers in oysters and the amount of metals in the sediments where they inhabit?

The effects exerted by metals in oysters are still a matter of debate and require more detailed studies. In this work we have investigated whether the health status of oysters are affected by the amount of metals present in the sediments of their habitat. Sediments and oysters were collected in the tidal part of the estuary of the Oka River (Basque Country), representative of other mesotidal, well mixed and short estuaries of the European Atlantic coast. The concentrations of 14 elements were determined in all the samples. Several biomarkers were also measured in the soft tissues of oysters. According to the concentrations found, the sediments were classified as non-toxic or slightly toxic. In good agreement, the histological alterations observed in oysters were not severe. Interestingly, in those sampling sites where the sediments showed relatively high metal concentrations, the metallic content in oysters was lower, and vice versa.

A chemical status predictor. A methodology based on World-Wide sediment samples.

As a consequence of the limited resources of underdeveloped countries and the limited interest of the developed ones, the assessment of the chemical quality of entire water bodies around the world is a utopia in the near future. The methodology described here may serve as a first approach for the fast identification of water bodies that do not meet the good chemical status demanded by the European Water Framework Directive (WFD). It also allows estimating the natural background (or reference values of concentration) of the areas under study using a simple criterion. The starting point is the calculation the World-Wide Natural Background Levels (WWNBLs) and World-Wide Threshold Values (WWTVs), two indexes that depend on the concentration of seven elements present in sediments. These elements, As, Cd, Cr, Cu, Ni, Pb and Zn, have been selected taking into account the recommendations of the UNEP (United Nations Environment Programme) and USEPA (United States Environmental Protection Agency), that describe them as elements of concern with respect to environmental toxicity. The methodology has been exemplified in a case study that includes 134 sediment samples collected in 11 transitional water bodies from 7 different countries and 4 different continents. Six of the water bodies considered met the good chemical status demanded by the WFD. The rest of them exceeded the reference WWTVs, at least for one of the elements. The estuaries of the Nerbioi-Ibaizabal (Basque Country) and Cavado (Portugal), the sea inlet of Río San Pedro (Spain), the Sepetiba Bay (Brazil) and the Yucateco lagoon (Mexico) belong to that group.

Prediction of Zamorano cheese quality by near-infrared spectroscopy assessing false non-compliance and false compliance at minimum permitted limits stated by designation of origin regulations.

Near-infrared transmittance (NIT) spectroscopy was used to predict the percentage in weight of the fat, dry matter, protein and fat/dry matter contents in Zamorano cheeses, protected with a Designation of Origin by the European Union. A total of 42 cheeses submitted to official control were analysed by reference methods. Samples were scanned (850-1050 nm) and predictive equations were developed using Partial Least Squares regression with a cross-validation step. Eight pretreatments independent from the remaining calibration samples were first considered. The most adequate one was that performing the second derivative (using a Savitzky-Golay method with a nine-point window and a second-order polynomial) followed by the standard normal variate transformation. Percentages of the root mean square error in cross-validation, the coefficient of determination and the mean of the absolute value of relative errors found were, respectively, for fat (0.62; 96.16; 1.05), dry matter (0.76; 96.03; 0.83), protein (0.41; 97.82; 0.81) and the fat/dry matter ratio (0.61; 92.51; 0.66). At a 99% confidence level, the trueness of the NIT+PLS methods for fat, dry matter and protein was verified. The official regulation for Zamorano cheese demands minimum permitted limits on the percentages in weight for protein (25%), dry matter (55%) and the ratio of fat to dry matter (45%). The adaptation of both the decision limit and the detection capability to the case of a minimum permitted limit (CDα and CDß, respectively) when a Partial Least Squares calibration is used has been applied for the first time for a food product protected by a Designation of Origin. The values of CDα with a probability of false non-compliance equal to 0.05 and of CDß when, in addition, the probability of false compliance was equal to or less than 0.05, both provided by the corresponding NIT+PLS-based method, were, respectively, for protein (24.78%; 24.57%), dry matter (54.14%; 53.28%) and the fat/dry matter ratio (44.39%; 43.78%).