A School Intervention Helps Decrease Daily Stress While Enhancing Social Integration in Children.

Stress coping is highly relevant during childhood. This study analyses how the participation in a behavioral intervention involving mindfulness-based practices and empathic collaboration activities impact on diurnal cortisol rhythm and social integration in children. In both experimental and waitlist groups, we evaluated before and after the intervention: daily stress, by sampling salivary cortisol at three measurement time-points, and social integration, assessed by a social preference index. Daily average cortisol (DAC) and the area under the curve (AUC) differed when comparing pre-post intervention values in both groups: in the experimental group these measures decreased while in the waitlist group DAC and AUC increased. At the end of the intervention, the experimental group showed an enhancement in the social preference index whereas this parameter diminished in the waitlist group. This kind of behavioral intervention seems to be effective at reducing daily stress and improving social integration in Primary School children.

Levels of PCBs in Oysters Coming from Galicia Coast: Comparison to Mussels from the Same Region.

PCBs were analyzed in two species of oyster (Crassostrea gigas and Ostrea edulis) cultured in intertidal beds and rafts coming from the Galician Rías during the period 2011-2014. PCBs were also analyzed in mussel (Mytilus galloprovincialis) collected in the same Rías during 2011. The main objective of this work is to investigate the distribution of PCBs in Galician oysters and to study their suitability as bioindicator in comparison to mussels. The levels of ΣPCBs (ten congeners) ranged from 5.58 to 179.49 ng g(-1) d.w. The effect of biological parameters (shell length, lipid content and condition index) on bioaccumulation of PCBs was also evaluated. ANOVA showed a statistically significant difference between species for higher chlorinated biphenyls (CBs 153 and 138). The spatial patterns were investigated. Principal Component Analysis (PCA) showed differences between geographical areas (Rías Altas, Centrales and Baixas) in the distribution of PCBs.

Optimization of a modified Captiva EMR-lipid method based on micro-matrix solid-phase dispersion coupled with gas chromatography-mass spectrometry for the determination of nine bisphenols in mussel samples.

This work describes a reliable, cheap, easy and fast method for analysis of nine bisphenols in mussel samples by gas chromatography-mass spectrometry after trimethylsilylation. The modified method consisted of miniaturized matrix solid phase dispersion (micro-MSPD) in a glass Pasteur pipette using Captiva EMR (enhanced matrix removal)-lipid as the sorbent. Good linearity was obtained in the work range (1-500 µg L-1) with a correlation coefficient (R2) ≥ 0.998. The method accuracy and precision were determined at two concentration levels. The results show recoveries ranging from 55 to 111%. The precision varied from 1.95 to 11.4% (RSD). The whole quantification limits were between 0.056 and 3.42 µg per kg dry weight. The analytical procedure was applied for the analyses of five mussel samples collected from Galician Rias. The major compound was BPA, and wild mussels from Rías de Ferrol, Vigo and A Coruña had the highest levels. The proposed method is suitable for the analysis of BPA and its analogues in mussel samples.

Spatial distribution and source identification of phthalates and organochlorine compounds in Galician mussels (NW Spain).

The spatial distribution of five phthalate esters (PAEs) and 17 organochlorine compounds (OCs) in wild and raft mussels from Galician littoral collected in 2020, and its relationship with anthropogenic activities was studied in this work. The Rías de Foz and Muros-Noia were the most polluted by PAEs, while the Rías de Ferrol and Barqueiro by PCBs. The highest levels of all contaminants were present in wild mussel, except DEHP that were predominant in raft mussel. The levels of most PAEs were negatively correlated with levels of the lower chlorinated PCBs and OCPs. The spatial distribution of pollutants confirmed by PCA was affected by the proximity to anthropogenic sources, phthalates by urban wastewater and PCBs by industrial inputs, mainly. The study of human exposure assessment suggests that Risk Quotient values were < 1, so the consumption of Galician raft mussels did not pose a risk to human health.

Optimization of micro-QuEChERS extraction coupled with gas chromatography-mass spectrometry for the fast determination of phthalic acid esters in mussel samples.

In this study, a new miniaturized version of the analytical method based on the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) technique using Florisil in the cleanup step for extracting six phthalic acid esters (PAEs) in mussel samples was developed by using a design of experiments. For this purpose, 1.5 mL of ultrapure water and later, 1.5 mL of acetonitrile were added to 0.1 g of the lyophilized sample, followed by 0.3 g of a commercial extraction salt packet (magnesium sulfate, sodium chloride, sodium citrate dihydrate, and sodium hydrogencitrate sesquihydrate). The recovered extract was purified using 0.1 g of Florisil. The final extract was evaporated and reconstituted in 1 mL of hexane. The six phthalates were determined by a GC-MS (SIM) system. The whole method was validated at two concentration levels. Recoveries ranged from 79% to 108%. Reproducibility in terms of coefficients of variation was between 4.9% and 12.1%. The limits of quantification of the whole method were between 0.53 and 38.0 µg per kg dry weight. Five mussel samples coming from the Galician Rías were analysed using this method. Except for three of the five samples where DnOP (di-n-octyl phthalate) was below the limit of quantification, all PAEs were found in concentrations that ranged between 1.99 and 372.7 µg per kg dry weight.

Assisted solvent extraction and ion-trap tandem mass spectrometry for the determination of polychlorinated biphenyls in mussels. Comparison with other extraction techniques.

A selective and sensitive analytical method for determination of ten congeners of polychlorinated biphenyls (PCBs 31, 28, 52, 101, 118, 153, 105, 138, 156, and 180) in mussel samples (Mytilus galloprovincialis) based on accelerated solvent extraction (ASE) and gas chromatography-tandem mass spectrometry (GC-MS-MS) is presented in this work. Extraction conditions were optimised using a Plackett-Burman factorial design. The final extracts were analysed after cleanup on alumina columns. The optimised extraction parameters were solvent percentage, sample amount, extraction temperature, pressure, static extraction time, flush percentage, and purge time. The results suggest that PCBs 118, 105, and 180 extractions appeared affected by only one statistically significant factor, pressure, solvent percentage and static extraction time, respectively. Extraction of PCBs 138 and 156 was affected by amount of sample. PCB 138 extraction was also statistically affected by static extraction time and purge time. Quantitative recoveries (64.8-120.3%) were achieved for all PCBs and method precision (RSD < 19%) was satisfactory.

Polychlorinated dibenzo-P-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBS) in bivalve mollusk from Galician Rías (N. W., SPAIN).

The concentrations of PCDD/Fs (2,3,7,8-chlorosubstituted) and three dioxin-like PCBs (PCB 77, PCB 126 and PCB169) were analyzed in bivalve mollusk collected in several Galician Rías between 2006 and 2014. Levels of Total PCDD/Fs ranged from 0.03 to 0.62 pg WHO-TEQ g-1 wet weight. Total dl-PCBs values were higher than Total PCDD/Fs and ranged from 0.01 to 2.11 pg WHO-TEQ g-1 wet weight. These concentrations were below those considered safe for human consumption. The PCDD/Fs profile was dominated by 2,3,4,7,8-PeCDF and 2,3,7,8-TCDF with a percentage of 24.95 and 23.87 of the Total PCDD/Fs, respectively. In relation to Total dl-PCBs, CB126 was the priority congener with the highest TEF value (0.1). Principal component analysis (PCAs) indicated a clear separation between the northern (Rías de Ferrol and Coruña) and southern Rías (Ría de Pontevedra and Vigo). The northern Rías were the highest contaminated one. Temporal trends showed important reduction rates suggesting that the regulations on dioxin like contaminants have been effective for quality waters in Galician Rías.

Levels and distribution patterns of polychlorinated biphenyl congeners in surface sediments from Galicia coast (Northwestern, Spain) according to granulometric characteristics.

In order to know distribution patterns of polychlorinated biphenyl congeners in the marine environment from Galida, PCBs n degrees 31, 28, 52, 101, 118, 153, 105, 138, 156 and 180 were isolated by Soxhlet extraction from three fractions of different particle size (<0.063 mm, 0.063-0.2 mm and >0.2 mm) in surface marine sediments; the quantification was performed using GC-MS and GC-ECD. Distribution of PCB congeners was shifted in favour of higher chlorinated compounds (CBs 138,153 and 180) and highly correlated to TOC content. In general, the finest fractions (<0.063 mm) of sediment presented the highest loadings of PCBs, only the sediment from As Pías zone exhibited the highest concentration of chlorinated congeners in the coarsest fraction. CB 52 concentration, slightly volatile compound, was related to water temperature. By means of multivariate techniques of data exploration as hierarchical duster analysis and principal components analysis, sediment samples from un-contaminated and slightly contaminated areas were clearly separated; groupings between samples from nearby zones appeared.

Distribution and trend of organochlorine pesticides in Galicia coast using mussels as bioindicator organisms. Possible relationship to biological parameters.

Contamination of organochlorine pesticides (OCPs) such as DDT and its metabolites (ΣDDs), γ-HCH (hexachlorocyclohexane), HCB (hexachlorobenzene), aldrin, endrin, isodrin and trans-nonachlor were investigated in wild mussels (Mytilus galloprovincialis) collected from Galician Rías (Rías of Ferrol, A Coruña, Muros, Arousa, Pontevedra and Vigo) during the period 1998-2012. Biological parameters, lipid content, shell length and condition index, were also studied. The OCPs levels in the wild mussel were in the order ΣDDs>γ-HCH>HCB. The other pesticides, aldrin, endrin, isodrin and trans-nonachlor, were not detected or were below the analytical detection limit. All concentrations found in these samples were below the allowable limits for human consumption (Regulation (EC) no. 396/2005). Univariate analysis confirmed that levels of some compounds presented significant relation with biological parameters. Multivariate analysis of the OCPs levels revealed significantly differences between studied Rías, samples from Ría of Ferrol had the highest levels of these compounds (values of ΣDDs ranged from 3.9 to 4.2 ng g(-1) ww) and samples from Ría of Arousa, the lowest levels (values of ΣDDs from 1.3 to 2.4 ng g(-1) ww). Temporal trends showed a decrease of OCPs levels along the studied period 1998-2012 in the Galician Rías.

Distribution and spatial trends of PCBs in commercial scallops from Galician littoral (NW, Spain). Possible influence of biometric parameters.

UNLABELLED: Levels and profiles of 10 individual congeners of polychlorinated biphenyls (PCBs) were studied in 3 species of commercial scallops (Pecten maximus, Chlamys varia, and Chlamys opercularis) from several Rías in Galician littoral (NW, Spain). ΣPCBs levels ranged from 2.21 to 41.0 ng/g wet weight for P. maximus, from 13.9 to 24.9 ng/g wet weight for C. varia, and from 1.58 to 24.3 ng/g wet weight for C. opercularis. The possible influence between biometric parameters (lipid content, condition index, and shell size) and PCBs levels were studied using statistical analysis (ANOVA). No relationship between biometric parameters could be established in the studied samples. Multivariate analysis showed there were differences in bioaccumulation of some PCBs congeners. Principal component analysis classifies clearly the 3 studied Rías (Ría de Ferrol, Ría de Arousa, and Ría de Vigo) taking into account PCBs levels found in the shellfish. PRACTICAL APPLICATIONS: We investigated levels and profiles of 10 congeners of PCBs in 3 commercial scallop species from the Galician littoral zone. The influence of 3 biometric parameters on polychlorinated biphenyls (PCBs) levels was also studied in order to assess results from the monitoring programs of production areas. According to PCBs levels, geographical differences were observed in commercial scallops from the 3 studied estuarine bays (Ría de Ferrol, Ría de Arousa, and Ría de Vigo).

Spatial and temporal trends of PCBs (polychlorinated biphenyls) in mussel from Galician coast (1998-2008).

PCBs were determined in wild mussel samples collected in several points from Galician Rías (Rías de Ferrol, A Coruña, Muros, Vigo and Arousa), Spain, during the period 1998-2008. The concentration levels of ΣPCBs ranged from 0.62 to 107.5 ng g(-1), w.w. The isomer concentrations in the Mytilus galloprovincialis were in the order hexachlorobiphenyls>pentachlorobiphenyls>tetrachlorbiphenyls>trichlorobiphenyls. CBs 153, 138 and 101 congeners were the most abundant in these samples. Two biological parameters, fat content and condition index (CI), have also been investigated for these mussel samples. Univariate techniques confirm that levels of some compounds, CBs 28, 52, 138, 153, and 180, presented significant relation (p<0.05) with biological parameters. Multivariate techniques of data exploration such as Principal Component Analysis (PCA) showed that spatial trends of PCB levels appeared in the studied samples. Rias de Ferrol and A Coruña presented the highest levels of PCBs and Ría de Arousa the lowest levels of these compounds. In general, temporal trends (linear regressions) showed a decrease of PCB levels along the period 1998-2008.

Spatial and temporal trends of PCDDs and PCDFs in bivalve mollusc coming from Galicia (2000-2005). Possible relationship between biometric parameters and PCDDs and PCDFs levels.

Levels and specific profiles of PCDD/F congeners were determined in bivalve mollusc coming from several Rías (estuarine bays) in Galicia (Spanish northwest Atlantic coast). Three species of bivalve mollusc, Mytilus galloprovincialis, Cerstoderma edulis and Ostrea edulis, from several points of littoral collected in the period from 2000 to 2005 were analysed. WHO-TEQ concentrations ranged from 0.08 to 1.62 pg g(-1) wet weight, values below the maximum concentration established by the EU. The PCDD/PCDF congeners profile in the studied samples was dominated by 2,3,7,8-TCDF and 2,3,4,7,8-PeCDF. The possible influence between biometric parameters (fat and condition index) and the culture type of mussel (wild or raft) on PCDDs and PCDFs levels were studied using statistical analysis. The coefficients of Pearson product-moment correlation indicated the existence of positive significant relationship between 2,3,7,8-TCDF and 2,3,4,7,8-PeCDF levels and fat content. There was not correlation between condition index and PCDD/Fs content. ANOVA also revealed there were significant differences between SigmaPCDD/Fs, 2,3,7,8-TCDF and 2,3,4,7,8-PeCDF levels in raft and wild mussels. Spatial and temporal trends were supported by patterns in ANOVA, using a general linear model (GLM) showing a clear separation in the composition of these compounds in more and less contaminated Rías and a decrease of PCDD/FS levels along the years.

Distribution of aliphatic compounds in bivalve mollusks from Galicia after the Prestige oil spill: spatial and temporal trends.

The content and distribution of n-alkane (C8-C35) and isoprenoid (pristane and phytane) hydrocarbons were investigated in two species of bivalve mollusk, mussel (Mytilus galloprovincialis) and cockle (Cerastoderma edule), collected at different points of the Galicia littoral zone during the period from December 2002 to February 2003 (after the Prestige oil spill). Samples were analyzed by high-resolution gas chromatography equipped with a flame ionization detector. The highest levels were found in mussels and cockles coming from two estuarine bays, Rías de Arousa and Vigo. Hydrocarbons with carbon chain length > 30 were detected and determined in all samples. The abundance of these hydrocarbons in biota could be interpreted with regard to the feeding and living habits. Chemometric techniques have been employed to analyze data and determine the potential source of hydrocarbon contamination. Differences between mussels and cockles were observed in relation to aliphatic content. According to the data analysis, the main source of hydrocarbon contamination of investigated samples seems to be more related to the intense traffic of vessels in these estuarine bays than to the Prestige oil spill.

Levels and distribution pattern of polychlorinated biphenyl (PCB) congeners in razor clams Ensis siliqua (Linnaeus, 1758) from Galicia (north-west Spain) in relation to biometric parameters.

To establish polychlorinated biphenyl (PCB) levels and distribution as well as their relationship to biometric parameters in the razor clam Ensis siliqua (Linnaeus, 1758), 15 individual samples collected from two points sited in the Islas Cies, Ría de Vigo in Galicia, Spain, collected monthly between February 2003 and April 2004, were analysed. PCBs (IUPAC No. 31, 28, 52, 101, 118, 153, 105, 138, 156 and 180) were isolated by Soxhlet extraction. Identification and quantification were performed by gas chromatography-mass spectrometry (GC/MS) and gas chromatography (electron capture detector), respectively. The isomer concentrations in E. siliqua were in the order hexachlorobiphenyls > pentachlorobiphenyls > heptachlorobiphenyls > trichlorobiphenyls > tetrachlorbiphenyls. No correlation was observed between the E. siliqua shell length and PCBs levels. The PCBs 31, 101, 105 and 153 levels were statistically related with some biometric parameters (p < 0.05). Multivariate techniques such as principal component analysis (PCA) show clear seasonal differences between samples.

Microwave-assisted extraction and mild saponification for determination of organochlorine pesticides in oyster samples.

A sample-preparation procedure (extraction and saponification) using microwave energy is proposed for determination of organochlorine pesticides in oyster samples. A Plackett-Burman factorial design has been used to optimize the microwave-assisted extraction and mild saponification on a freeze dried sample spiked with a mixture of aldrin, endrin, dieldrin, heptachlor, heptachorepoxide, isodrin, transnonachlor, p, p'-DDE, and p, p'-DDD. Six variables: solvent volume, extraction time, extraction temperature, amount of acetone (%) in the extractant solvent, amount of sample, and volume of NaOH solution were considered in the optimization process. The results show that the amount of sample is statistically significant for dieldrin, aldrin, p, p'-DDE, heptachlor, and transnonachlor and solvent volume for dieldrin, aldrin, and p, p'-DDE. The volume of NaOH solution is statistically significant for aldrin and p, p'-DDE only. Extraction temperature and extraction time seem to be the main factors determining the efficiency of extraction process for isodrin and p, p'-DDE, respectively. The optimized procedure was compared with conventional Soxhlet extraction.

Design of a field flow preconcentration system for cadmium determination in seawater by flow-injection-atomic absorption spectrometry.

A field flow preconcentration system (FFPS) for cadmium determination in seawater is described. Seawater samples are collected and preconcentrated in situ by passing them with a peristaltic pump through a minicolumn packed with Amberlite XAD-4 impregnated with the complexing agent 1-(2-pyridylazo)-2-naphthol. Thus, cadmium is complexed, retained, and preconcentrated without the interference of the saline matrix. Minicolumns loaded with cadmium are then returned to the laboratory where they are incorporated into a flow injection system and eluted with a small volume of an ethanolic solution of hydrochloric acid into the nebuliser-burner system of a flame atomic absorption spectrometer. The optimization of FFPS design is presented, and the stability and characteristics of the Cd-loaded minicolumns are studied in detail. The detection limit for Cd in seawater based on an enrichment factor of 1059 was 3.8 ng l(-1). The precision (R.S.D.) obtained for different amounts of cadmium was in the range 4.1-6.5% at the 25-100 ng l(-1) level. Analysis of certified reference materials (SLEW-3 and NASS-5) showed good agreement with the certified value. This procedure was applied to the determination of cadmium in seawater samples from Galicia (Spain).

Field sample preconcentration of copper in sea water using chelating minicolumns subsequently incorporated on a flow-injection-flame atomic absorption spectrometry system.

A field flow preconcentration system for copper determination in seawater is described. Seawater samples are collected and preconcentrated in situ by passing them using a peristaltic pump through a minicolumn packed with Amberlite XAD-4 impregnated with the complexing agent 1-(2-pyridylazo)-2-naphthol. Thus, copper is preconcentrated without the interference of the saline matrix. Once in the laboratory, the minicolumns loaded with copper are incorporated on a flow injection system and eluted with a small volume of a 20% (v/v) ethanolic solution of 0.5 mol L-1 hydrochloric acid into the nebuliser-burner system of a flame atomic absorption spectrometer. The analytical figures of merit for the determination of copper are as follows: detection limit (3s), 0.06 microgram L-1; precision (RSD), 1.2% for 2 micrograms L-1; enrichment factor, 30 (using 25 mL of sample and 83 microL of eluent). Analysis of certified reference materials (SLEW-3 and NASS-5) showed good agreement with the certified value. This procedure was applied to the determination of copper in seawater samples from Galicia (Spain).