Goose barnacle Pollicipes pollicipes as biomonitor of metal contamination in the northwest coast of Portugal

The main objective of this work was to assess the potential use of goose barnacle Pollicipes pollicipes as biomonitor of metal contamination in northwest (NW) coast of Portugal. The concentrations of Cd, Cr, Cu, Fe, Mn, Ni and Zn were determined in coastal seawaters and tissues of P. pollicipes, which allowed establishing correlations between metals in coastal seawaters and P. pollicipes and calculating metal bioaccumulation factors (BAFs). The results of this study showed that P. pollicipes soft tissues can be used for monitoring metal contamination in these coastal seawaters: (1) there were significant correlations (p??0.05); (2) soft tissues were sensitive to spatial variations of metal bioavailabilities and their concentrations ranged 0.70-2.22?mg?Cd?kg(-1), 0.49-1.40?mg?Cr?kg(-1), 1.37-2.07?mg?Ni?kg(-1), 2.4-3.3?mg?Cu?kg(-1), 5-59?mg?Mn?kg(-1), 134-578?mg?Fe?kg(-1)and 728-1,854?mg?Zn?kg(-1); (3) mean logarithmic bioaccumulation factors (log BAF) of Fe, Cd and Zn were higher, 5.57, 5.47 and 4.41, respectively, than mean log BAFs of Cr, Mn, Cu and Ni, 4.18, 4.14, 3.98 and 3.51, respectively. In contrary, P. pollicipes shell plates were not considered ideal material to monitor metal bioavailabilities in these coastal seawaters. Regarding the very high concentrations of Zn obtained in the coastal seawaters and P. pollicipes soft tissues, the NW coast of Portugal should be classified as "Class III/IV - Remarkably/Highly Polluted".     

N-nitrosodimethylamine and trihalomethane formation and minimisation in Southeast Queensland drinking water

This study assesses the prevalence of disinfection by-product (DBP) precursors in some Southeast Queensland drinking water sources by conducting formation potential experiments for the four regulated trihalomethanes (THMs), and the potent carcinogen, N-nitrosodimethylamine (NDMA). NDMA formation potentials were consistently low (<5-21 ng/L), and total THM (tTHM) formation potentials were consistently below the Australian Drinking Water Guideline (250 μg/L). NDMA concentration of finished drinking waters was also monitored and found to be <5 ng/L in all cases. The effect of coagulation and advanced oxidation on the formation of NDMA and THMs is also reported. UV/H(2)O(2) pre-treatment was effective in producing water with very low THMs concentrations, and UV irradiation was an effective method for NDMA degradation. H(2)O(2) was not required for the observed NDMA degradation to occur. Coagulation using alum, ferric chloride or poly(diallyldimethylammonium chloride) (polyDADMAC) was ineffective in removing DBPs precursors from the source water studied, irrespective of the low dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) attained. Rather, coagulation with polyDADMAC caused an increase in NDMA formation potential upon chloramination, and all coagulants led to an increased tTHM formation potential upon chlorination due to the high bromide concentration of the source water studied.     

Fractionation of heavy metals and assessment of contamination of the sediments of Lake Titicaca

Chemical weathering is one of the major geochemical processes that control the mobilization of heavy metals. The present study provides the first report on heavy metal fractionation in sediments (8–156 m) of Lake Titicaca (3,820 m a.s.l.), which is shared by the Republic of Peru and the Plurinational State of Bolivia. Both contents of total Cu, Fe, Ni, Co, Mn, Cd, Pb, and Zn and also the fractionation of these heavy metals associated with four different fractions have been determined following the BCR scheme. The principal component analysis suggests that Co, Ni, and Cd can be attributed to natural sources related to the mineralized geological formations. Moreover, the sources of Cu, Fe, and Mn are effluents and wastes generated from mining activities, while Pb and Zn also suggest that their common source is associated to mining activities. According to the Risk Assessment Code, there is a moderate to high risk related to Zn, Pb, Cd, Mn, Co, and Ni mobilization and/or remobilization from the bottom sediment to the water column. Furthermore, the Geoaccumulation Index and the Enrichment Factor reveal that Zn, Pb, and Cd are enriched in the sediments. The results suggest that the effluents from various traditional mining waste sites in both countries are the main source of heavy metal contamination in the sediments of Lake Titicaca.     

Altered growth and enzyme expression profile of ZnO nanoparticles exposed non-target environmentally beneficial bacteria

The extensive production and usage of nanoparticles with ultimate disposal in the environment leads to unintentional exposure of non-target environmentally beneficial bacteria thereby posing a serious threat to the native soil inhabitants. Soil microflora is an important link in the biogeochemical cycling of nutrients, affecting ecosystem functioning and productivity. This study evaluates the effect of one of the widely used nanoparticles, zinc oxide on two predominant soil bacteria, Gram-positive Bacillus subtilis and Gram-negative Pseudomonas aeruginosa with respect to their biocatalytic activities. Growth profiles of these bacteria in the presence of zinc oxide nanoparticles (ZnONPs) at a concentration of 20 ppm exhibited a prolonged lag phase in B. subtilis, whereas no significant effect was observed in the case of P. aeruginosa even at 200 ppm. Interestingly, the enzymatic profile of both the organisms was affected at non-lethal ZnONPs concentrations. The most pronounced effect was on the enzymes associated with amylolytic activity, denitrification and urea degradation wherein total inhibition of activity was noted in B. subtilis. The enzyme activities were lowered in the case of P. aeruginosa. The results presented here reiterate a critical need for exposure assessment and risk characterization of nanomaterial disposal on soil microflora while formalizing waste management strategies.     

Changes in the trade in native medicinal plants in Brazilian public markets

Plants continue to be an important source of new bioactive substances. Brazil is one of the world’s mega-diverse countries, with 20 % of the world’s flora. However, the accelerated destruction of botanically rich ecosystems has contributed to a gradual loss of native medicinal species. In previous study, we have observed a fast and intensive change in trade of medicinal plants in an area of Amazon, where human occupation took place. In this study, we surveyed 15 public markets in different parts of Brazil in search of samples of 40 plants used in traditional medicine and present in first edition of Brazilian Official Pharmacopoeia (FBRAS), published in 1926. Samples of plants commercialized as the same vernacular name as in Pharmacopoeia were acquired and submitted to analysis for authentication. A total of 252 plant samples were purchased, but the laboratory analyses showed that only one-half of the samples (126, 50.2 %) were confirmed as the same plant species so named in FBRAS. The high number of unauthenticated samples demonstrates a loss of knowledge of the original native species. The proximity of the market from areas in which the plant occurs does not guarantee that trade of false samples occurs. The impact of the commerce of the substitute species on their conservation and in public health is worrying. Strategies are necessary to promote the better use and conservation of this rich heritage offered by Brazilian biodiversity.     

Adjusting the effect of seasonal variability in the bioassessment of streams

Bioassessment tools should distinguish between the effects of anthropogenic degradation in communities and natural temporal changes. The present study tests the influence of natural seasonal variability on macroinvertebrate stream communities assessed by a predictive model (PORTRIV) and a multimetric index (IPtI) calibrated for spring. The scores of PORTRIV decreased significantly between spring and autumn, and between spring and winter (ca. 37 to 53 %, respectively), while those of IPtI did not change significantly between seasons. For non-reference samples, the results of the predictive model also indicate no significant differences. A correction factor (CF) was calculated to adjust the existing differences in the model assessments between seasons, based on the percentage of variation of reference site scores from spring to autumn and winter. After the application of the CF to the OE50 scores of spring reference samples, the differences were no longer significant. Independent reference validation sites confirmed this tendency. This method has the advantage of avoiding large efforts required for the construction of databases from other seasons and the development of new models to allow the assessment of streams in seasons other than spring. Further tests with models developed in regions with more marked seasonal changes should be done to confirm its wider applicability.     

Impact of water quality on bacterioplankton assemblage along Cértima River Basin (central western Portugal) assessed by PCR–DGGE and multivariate analysis

The information on bacterial community composition (BCC) in Portuguese water bodies is very scarce. Cértima River (central western Portugal) is known to have high levels of pollution, namely organic. In the present work, the BCC from a set of 16 water samples collected from Cértima River Basin and its main tributaries was characterized using 16S rDNA–denaturing gradient gel electrophoresis, a culture-independent molecular approach. Molecular data were related to environmental parameters through multivariate analysis to investigate potential impact of water pollution along the river. Principal component analysis using environmental data showed a water quality gradient from more pristine waters (at the mountain tributaries) to waters with increasingly eutrophic potential (such as Fermentelos Lake). This gradient was mainly defined by factors such as organic and inorganic nutrient sources, electrical conductivity, hydrogen carbonate concentration, and pH. Molecular results showed variations in BCC along Cértima River Basin but in the main river section, a Bacteroidetes phylotype (Flavobacterium sp.) proved to be dominant throughout the river course. Multivariate analysis suggests that spatial variation of BCC along the Cértima River Basin depended mainly on parameters such as Chl a, total suspended solid (TSS), total organic carbon, electrical conductivity, and HCO _boxclose^-_{3}^{-} levels. Bacteroidetes phylotypes were all related to higher electrical conductivity and HCO₃^-_{3}^{-} levels although some of these were also correlated with high SO₄^2-_{4}^{2-} and others with high soluble reactive phosphorus, nitrate, TN, and Kjeld-N levels. The Gammaproteobacteria occurrence was correlated with high SO₄^2-_{4}^{2-} levels. One of the Betaproteobacteria phylotypes showed to correlate with low redox potential (E_h) and high temperature, pH, TSS, and Chl a levels while another one showed a negative correlation with Chl a values.     

Terrain Discontinuity Effects in the Regional Flow of a Complex Karstified Aquifer

Karst aquifers are characterized by spatial heterogeneity due to the presence of highly permeable channels and conduits in low-permeable fractured rocks (matrix block). Recent studies have reported a close relationship between surface and subsurface water in karstic regions due to the water flow through a complicated network of paths formed by fracture intersections. Subsurface flow in karstified aquifers ranges between conduit flow, in large passages with relatively high flow velocities, and diffuse flow, in the matrix block where Darcy’s law is still valid. In this paper, we present the simulation of a complex karstified aquifer system in Crete, Greece, where the presence of main faults drastically affects the regional flow. A discrete fracture approach in conjunction with an equivalent porous medium approach was adopted to simulate the mixed flow in the area of interest. The simulation results have shown that the length and the orientation of the dominant faults, primarily during the rainy season, affect the flow field.