Release of silver and titanium from face masks traded for the general population.

Previous assessments of a selection of face masks intended for the general population in Belgium found that silver (Ag)-based biocides were present in masks advertised for antimicrobial properties; whereas titanium dioxide (TiO2) particles were detected in all the face masks in at least one layer corroborating its widespread use in the textile industry. The presence of Ag-based biocides and TiO2 particles in face masks raised questions on the possibility of release under normal wearing conditions, which could potentially cause a health risk to the consumers. Direct measurement of release of Ag and TiO2 particles during normal wearing is problematic by the lack of methodology to test release and to quantify inhaled particles. Therefore in this study, we investigated leaching experiments using artificial acid sweat as a method to evaluate the release of Ag-based biocides and TiO2 particles present in face masks. Leaching experiments were proposed as an alternative method to evaluate the quality of face masks, and as a higher tier method to assess face masks that are not safe-by-design. Results from leaching experiments showed that Ag was released in amounts varying from 0.03 up to 36 % of total Ag content, in four out of the eight face masks that claimed antimicrobial properties and that contained Ag. The leaching data of titanium (Ti) showed that despite TiO2 being detected in all face masks, only in one mask Ti was measured in detectable concentrations in artificial sweat (0.35 % of total Ti content). Comparison of leachable Ag and Ti with respective acceptable exposure limit values derived from inhalation exposure limits indicate that three face masks would need further risk assessment and could not be considered as intrinsically safe.

Pesticides, trace elements and pharmaceuticals in tea samples available in Belgian retail shops and the risk associated upon acute and chronic exposure.

Over the last decade, the consumption of tea and herbal tea has gained more and more popularity across the globe, but the potential presence of chemical contaminants (e.g. pesticides, trace elements, synthetic drugs) may raise health concerns. This study analysed selected teas available in Belgian retail stores and performed a risk assessment for these samples. No chemical adulteration could be detected in dry tea material. More than 38% of the dry leaves samples contained at least one pesticide exceeding the maximal residue level (MRL) set by the EU. However, further risk assessment, based on the values of pesticide residues and the toxic trace elements encountered in the brew, demonstrate that the consumption of these teas will not give rise to health concerns. Nonetheless, attention should be given to the leaching potential of nickel from teas and the presence of arsenic in brews from algae containing teas.

Exposure of humic acid-coated goethite colloids to groundwater does not affect their adsorption of metal(loid)s and their impact on Daphnid mobility.

Engineered humic acid-coated goethite (HA-Goe) colloids find increasing application in in situ remediation of metal(loid)-polluted groundwater. Once introduced into the subsurface, the colloids interact with groundwater altering their physicochemical properties. In comparison to freshly synthesized, unreacted HA-Goe colloids, such alterations could reduce the adsorption affinity towards metal(loid)s and also result in altered ecotoxicological effects. In our study, HA-Goe colloids were exposed to two groundwaters (low vs. high concentrations of metal(loid)s) from two metal(loid)-contaminated sites for 87 days. We investigated (i) the course of HA-Goe ecotoxicity (Daphnia magna immobilization tests), (ii) HA-Goe adsorption properties (multi-element solutions containing As, Cu, Zn, Ni and Co), and (iii) changes in the chemical composition as well as in the mineral and aggregate properties of HA-Goe. The adsorption affinity of HA-Goe decreased in the order As ≈ Cu ≫ Zn > Ni ≈ Co. The metal(loid) adsorption occurred rapidly after mixing prior to the first sampling, while the duration of ongoing exposition to groundwater had no effect on the adsorption of these metal(loid)s. We neither observed a desorption of humic acids from the goethite surface nor alterations in the mineralogy, crystallinity, and surface properties of HA-Goe. Standardized Daphnia magna immobilization tests showed an increased number of mobile organisms with increasing exposure time of HA-Goe to both groundwaters. The decrease in HA-Goe-mediated immobilization of D. magna was strongest within the first 30 d. We attribute this to a shift to smaller sizes due to the breakdown of large HA-Goe aggregates, particularly within the first 30 d. The breakdown of these µm-sized aggregates may result mainly from the repeated shaking of the HA-Goe suspensions. Our study confirms within this particular setting that the tested HA-Goe colloids are suitable for the long-term immobilization of metal(loid)s, while lethal effects on D. magna were negligible.

Field-scale demonstration of in situ immobilization of heavy metals by injecting iron oxide nanoparticle adsorption barriers in groundwater.

Remediation of heavy metal-contaminated aquifers is a challenging process because they cannot be degraded by microorganisms. Together with the usually limited effectiveness of technologies applied today for treatment of heavy metal contaminated groundwater, this creates a need for new remediation technologies. We therefore developed a new treatment, in which permeable adsorption barriers are established in situ in aquifers by the injection of colloidal iron oxides. These adsorption barriers aim at the immobilization of heavy metals in aquifers groundwater, which was assessed in a large-scale field study in a brownfield site. Colloidal iron oxide (goethite) nanoparticles were used to install an in situ adsorption barrier in a very heterogeneous, contaminated aquifer of a brownfield in Asturias, Spain. The groundwater contained high concentrations of heavy metals with up to 25 mg/L zinc, 1.3 mg/L lead, 40 mg/L copper, 0.1 mg/L nickel and other minor heavy metal pollutants below 1 mg/L. High amounts of zinc (>900 mg/kg), lead (>2000 mg/kg), nickel (>190 mg/kg) were also present in the sediment. Ca. 1500 kg of goethite nanoparticles of 461 ± 266 nm diameter were injected at low pressure (< 0.6 bar) into the aquifer through nine screened injection wells. For each injection well, a radius of influence of at least 2.5 m was achieved within 8 h, creating an in situ barrier of 22 × 3 × 9 m. Despite the extremely high heavy metal contamination and the strong heterogeneity of the aquifer, successful immobilization of contaminants was observed in the tested area. The contaminant concentrations were strongly reduced immediately after the injection and the abatement of the heavy metals continued for a total post-injection monitoring period of 189 days. The iron oxide particles were found to adsorb heavy metals even at pH-values between 4 and 6, where low adsorption would have been expected. The study demonstrated the applicability of iron oxide nanoparticles for installing adsorption barriers for containment of heavy metals in contaminated groundwater under real conditions.

Surface soil liming reduces cadmium uptake in cacao seedlings but subsurface uptake is enhanced.

Cadmium concentrations in cacao (Theobroma cacao L.) beans from South America often exceed trade limits. Liming soil is advocated as a remediation option, but amendments cannot be incorporated into the entire root zone without harming the trees. An experiment was set up to identify how Cd uptake varies within the root zone when surface and subsurface soil layers are either limed or not. The experiment used 22-cm-height pots with top and bottom layers using surface and subsurface soil samples from a cacao field. The potted soils were either surface limed or not or fully limed and layers spiked with stable 108 Cd isotope in various combinations to trace the plant Cd provenance. The root distribution was neither affected by liming nor by soil source; 70% of the root biomass was present in the top layer. Plants grown on the fully limed surface soil had 1.7 times lower Cd concentrations in leaves than the unlimed treatments, whereas this concentration was 1.2 times lower when only the top layer was limed (surface soil used in both layers). The isotope dilution data showed that surface soil liming enhanced Cd uptake from the unlimed bottom layer compared with the unlimed soil, suggesting compensating mechanisms. The pots containing surface soil over subsurface soil also showed that compensating effect but, due to lower phytoavailable Cd in the subsurface soil, surface liming still effectively reduced foliar Cd. We conclude that liming might be a feasible mitigation strategy, but its effectiveness is limited when Cd phytoavailability remains untreated in the subsurface layer.

The impact of fermentation on the distribution of cadmium in cacao beans.

A large fraction of the South-American cacao production is affected by new cadmium (Cd) regulations in cacao. This work was set up to characterize the distribution and speciation of Cd within the cacao fruit and to monitor potential Cd redistribution during cacao fermentation. In cacao fruits from four locations, Cd concentrations decreased with testa > nib ~ placenta ~ pod husk > mucilage. The distribution of Cd within cacao beans was successfully visualized using laser ablation inductively coupled plasma spectrometry (LA-ICP-MS) and confirmed higher Cd concentrations in the testa than in the nib. Speciation analysis by X-ray absorption spectroscopy (XANES) of unfermented cacao beans revealed that Cd was bound to O/N-ligands in both nib and testa. Fermentation induced an outward Cd migration from the nibs to the testa, i.e. against the total concentration gradient. This migration occurred only if the fermentation was sufficiently extensive to decrease the pH in the nib to <5.0, likely as a result of increased Cd mobility due to organic acid penetration into the nibs. The change in dry weight based nib Cd concentrations during fermentation was, on average, a factor 1.3 decrease. We propose that nib Cd can be reduced if the nib pH is sufficiently acidified during fermentation. However, a balance must be found between flavor development and Cd removal since extreme acidity is detrimental for cacao flavor.

Soil properties and agronomic factors affecting cadmium concentrations in cacao beans: A nationwide survey in Ecuador.

Recent cadmium (Cd) regulation in chocolate threatens the sustainability of cacao production in Southwest America. Cadmium contamination in cacao beans has not been assessed at a country level. A nationwide survey was conducted in Ecuador to identify the spatial distribution of Cd in cacao beans, as well as soil and agronomic factors involved. Paired soil and plant samples (pods and leaves) were collected at 560 locations. Information on agronomic practices was obtained through a prepared questionnaire for farmers. Total soil Cd averaged 0.44 mg kg-1 which is typical for young and non-polluted soils. Mean Cd concentration in peeled beans was 0.90 mg kg-1 and 45% of samples exceeded the 0.60 mg kg-1 threshold. Bean Cd hotspots were identified in some areas in seven provinces. Multivariate regression analysis showed that bean Cd concentrations increased with increasing total soil Cd and with decreasing soil pH, oxalate-extractable manganese (Mnox) and organic carbon (OC) (R2 = 0.65), suggesting that Cd solubility in soil mainly affects Cd uptake. Bean Cd concentration decreased a factor of 1.4 as the age of the orchard increased from 4 to 40 years. Bean Cd concentration was inconsistently affected by genotype (CCN-51 vs. Nacional), pruning or application of fertilizers. It is concluded that the relatively larger bean Cd concentrations in Ecuador are related to the high Cd uptake capacity of the plants combined with their cultivation on young soils, instead of Cd depleted weathered soils. Mitigation strategies should consider the application of amendments to modify such soil properties to lower soil Cd availability. There is scope for genetic mitigation strategy to reduce bean Cd, but this needs to be properly investigated.

Natural colloidal P and its contribution to plant P uptake.

Phosphorus (P) bioavailability depends on its concentration and speciation in solution. Andisols and Oxisols have very low soil solution concentration of free orthophosphate, as they contain high concentrations of strongly P-sorbing minerals (Al/Fe oxyhydroxides, allophanes). Free orthophosphate is the form of P taken up by plants, but it is not the only P species present in the soil solution. Natural colloidal P (P associated with Al, Fe, and organic matter of sizes ranging from 1 to 1000 nm) constitutes an important fraction of soil solution P in these soils; however, its availability has not been considered. We measured the uptake of P by wheat (Triticum aestivum) from radiolabeled nonfiltered (colloid-containing) and 3-kDa filtered (nearly colloid-free) soil-water extracts from Andisols and Oxisols. In the Andisol extracts, P uptake was up to 5-fold higher from the nonfiltered solutions than the corresponding 3-kDa filtered solutions. In the Oxisol extract, no difference in P uptake between both solutions was observed. Also the diffusional flux of P as measured with the DGT technique was larger in the nonfiltered than in the 3-kDa filtered solutions. Our results suggest that colloidal P from Andisols is not chemically inert and contributes to plant uptake of P.

Patterns of recurrence and survival in breast cancer.

Breast cancer is the leading cause of death affecting women worldwide, according to mortality estimation and incidence. In Chile, breast cancer ranks third among cancer mortality rates. Two-hundred and eighty-three breast cancer patients registered at the Gustavo Fricke Hospital of Viña del Mar, Chile, were studied to assess the influence of several factors on the recurrence and survival of breast cancer patients. Patients selected had 5-year post-surgery recurrences of breast cancer and had an average of 58.5 years of age. The variables considered in these patients were the quadrants involved, stage of the tumor, type of recurrence, type of exams, type of surgery, the grade of tumor in relation to Broder's classification and pathology of tumor. The results indicated that the superior external right and left quadrants, Stage IIA, loco-regional recurrences, lumpectomies with axillar lymph node removal and after 5 years, Grade II were prevalent in this population. Among the pathologies analyzed, the ductal carcinomas were the most commonly found and were positive for PCNA, beta-catenin, cytokeratin 18 and ErbB2 protein expression. A median follow-up of 60 months of survival was achieved in 95% of patients. However, those cases with a recurrence of breast cancer had only 40% survival. The risk of mortality was significantly greater when recurrence was present (P<0.0001). The global probability of survival of the patients reached 72% after 5 years. It can be concluded that early detection of breast cancer allows for control of the disease and avoids remissions, or at least extends survival.