The source and fate of sediment and mercury in the Tapajós River, Pará, Brazilian Amazon: Ground- and space-based evidence

We present results of mercury (Hg) in surface waters and soils and an analysis of satellite imagery from the Tapajós River basin, Brazilian Amazon, and the Reserva Garimpeira do Tapajós, the legal gold mining district of the basin. Hg bound to suspended sediment was roughly 600 and 200 times the concentration of dissolved Hg per litre of water, in impacted and pristine areas, respectively. Suspended sediments thus represent the major pathway of river-borne Hg. Median concentrations of Hg in suspended load from both impacted and pristine waters were 134 ppb, and 80% of samples were below 300ppb-in the range of naturally occurring surficial materials in the tropics. Regionally, riverine Hg fluxes were proportional to the concentration of total suspended solids. This shows that the dominant source of Hg is the sediment itself rather than anthropogenic mercury discharge from the small-scale mines. To independently test this conclusion, a mass balance was performed. A conservative calculation of the annual export of mercury (Hg) from the Creporí River (a minimum) was 1.6 tonnes for the year 1998-it could be significantly larger. This amount of Hg is difficult to account for by anthropogenic discharge alone, confirming that enhanced physical erosion caused by sluicing and dredging operations is the dominant source of Hg. We therefore conclude that gold mining operations are primarily responsible for elevated Hg concentrations. The dominant source of contamination is not, however, the loss of Hg in the gold amalgamation process. Rather, the disturbance and mobilization of large quantities of Hg-rich sediment and floodplain soil into the water column during mining operations is the source of contamination. These findings shift the focus of remediation and prevention efforts away from Hg control toward soil and sediment erosion control. The minimization or elimination of Hg losses in the mining process remains important for the health of local peoples and environments, but keeping basin soils and sediments in place would be a much more effective means of minimizing Hg fluxes to the region's rivers. To gain a spatial and historical perspective on the source and extent of emissions, satellite imagery was used. We were able to reconstruct historical mining activity, locate impacted areas, and estimate historical Hg fluxes with the imagery. To do so, the spectral characteristics of satellite images were calibrated to the concentration of suspended sediment in the rivers, which, in turn, is proportional to the Hg concentration. This analysis shows that mining-induced sediment plumes have been a dominant source of sediment to the Tapajós River system for decades. As well, the intensity and location of these emissions has varied through time. For example, sediment discharge from the Creporí River was greater in 1985 than in 1998; and the tributaries on the west bank of the Tapajós were actively being mined in 1985 but had been abandoned in 1998. This type of information should greatly assist in understanding original and ongoing sources of emissions, and in managing prevention and remediation efforts.     

Sonophotocatalytic degradation of alazine and gesaprim commercial herbicides in TiO2 slurry

The photocatalytic degradation of alazine and gesaprim commercial herbicides was carried out in aqueous TiO(2) suspensions under UV light (15W, 352 nm). Degradation of these herbicides was also observed by the combined effects of photocatalysis with sonolysis (sonophotocatalysis) using an ultrasound source of 20kHz. Degradation profiles were recorded by measuring the concentration of the active compounds present in the alazine (alachlor and atrazine) and gesaprim (atrazine) by HPLC as a function of irradiation time (sound and/or light). Over 90% of the active component in the gesaprim was abated and those in alazine were completely degraded. The content of total organic carbon and chemical oxygen demand was also monitored. Mineralization of the commercial herbicides was achieved. Over 80% of chemical oxygen demand abatement was attained for both herbicides with sonophotocatalysis at 150 min of irradiation time. The photocatalytic degradation of the herbicides followed a pseudo-first order kinetics and their rate constant was increased by the combined effects of sonolysis.     

Development of mixed conducting membranes for clean coal energy delivery

Mixed conducting membranes can be used for the separation of oxygen from air in both coal gasification and oxy-fuel power plants. In this review paper, the basic perovskite and non-perovskite structures, composition, properties and performance are addressed. Two typical perovskite materials, BSCF and LSCF, show promise in industrial applications as their oxygen fluxes are at least one order of magnitude higher than non-perovskite membranes. BSCF membranes are now delivering oxygen fluxes in excess of 5 ml min^?1 cm^?2. Latest developments in perovskite composition, effects of impurities in membrane performance and membrane geometry are discussed giving an insight into the potential utilisation in clean energy delivery processes. Strategies for improving membranes performance using unit operations with different geometries and possible future technologies are also addressed.     

Biodegradable Films Based on Blends of Gelatin and Poly (Vinyl Alcohol): Effect of PVA Type or Concentration on Some Physical Properties of Films

The aim of this work was to develop biodegradable films based on blends of gelatin and poly (vinyl alcohol) (PVA), without a plasticizer. Firstly, the effect of five types of PVA with different degree of hydrolysis (DH) on the physical properties of films elaborated with blends containing 23.1% PVA was studied. One PVA type was then chosen for the study of the effect of the PVA concentration on the mechanical properties, color, opacity, gloss, and water solubility of the films. The five types of PVA studied allowed for films with different characteristics, but with no direct relationship with the DH of the PVA. Therefore, the PVA Celvol^®418 with a DH = 91.8% was chosen for the second part, because they produced films with greater tensile strength. The PVA concentration affected all studied properties of films. These results could be explained by the results of the DSC and FTIR analyses, which showed that some interactions between the gelatin and the PVA occurred depending on the PVA concentration, affecting the crystallinity of the films.     

Development of a dynamic model to predict PM10 emissions from swine houses

Influences on dust emissions from livestock operations are number, weight, and kind of animals and characteristics of the housing system. Differences between facilities cannot be explained solely by mechanistic input variables. The objective of this study was to characterize the main input variables for modeling emissions of particulate matter with a mass median diameter < or = 10 microm (PM10) from swine facilities using a data-based model. Investigations were performed in mechanically ventilated facilities for weaning, growing-finishing, and sows in Italy and Germany. The measurements included inside and outside concentration of airborne PM10 particles (scatter light photometry), ventilation rate (calibrated measuring fans), indoor air climate at a measuring frequency of 60 s, feeding times, and animal-related data such as weight and animal activity. Dust concentration and emission were simulated using a dynamic transfer function. The results indicated that the average PM10 emission rate was influenced considerably by housing system. The simulation of the PM10 emission rate resulted in a mean percentage error per data set of 21 to 39%, whereas the average simulated and measured emission rate per data set differed by about 4 to 19%. High prediction errors occurred especially during situations in which the absolute level and spatial location of the measured activity peaks did not correspond with the measured dust peaks. Further recommendations of the study were to improve continuous and accurate measurements of input variables, such as the activity level in animal houses, and to optimize the amount of measuring days in relation to the model accuracy.     

A review of regulatory decisions for environmental protection: part II - the case-study of contaminated land management in Portugal

This paper provides a case-study analysis of the challenges in the implementation of national soil policies, which was developed by the authors in Part I of the review of regulatory decisions for environmental protection [Rodrigues SM, Pereira ME, Ferreira da Silva E, Hursthouse A, Duarte AC. A review of regulatory decisions for environmental management: Part I-challenges in the implementation of national soil policies. Environ Int 2009. doi:10.1016/j.envint.2008.08.007]. The Portuguese case was selected as a case-study since specific regulatory decisions for contaminated land management are still in the early stages of development. Given the gap between the situation at the EU level and the state of Portuguese soil policy development, it is of merit to consider national contaminated land policy regimes already in place within the EU and to see if these provide a suitable basis to define the main challenges and research needs for the implementation of a Portuguese contaminated land management strategy. A framework combining the D-P-S-I-R (drivers-pressures-sources-impacts-responses) structure of policy evaluation with the Source-Pathway-Receptor approach to health risk assessment is proposed to derive an effective regulatory framework for managing contaminated land in Portugal, using available information and only to develop new data and research where knowledge gaps exist. Funding site clean-up and assigning liability were identified as relevant factors currently hampering site remediation. Most relevant research needs for the development of contaminated land management practices in Portugal are those associated to the definition of a risk assessment framework and setting guidelines for the evaluation of risks posed to both humans and ecosystems. Other relevant and innovative features are the integration of soil function analysis into site investigations and the definition of a framework that combines risk assessment with soil function analysis. The analysis of the Portuguese case also provides insight into the discussions needed for the effective development of regulatory decisions for contaminated land management in countries with no history of implementing specific soil policies.     

Association between micronuclei frequency in pollen mother cells of Tradescantia and mortality due to cancer and cardiovascular diseases: A preliminary study in Sao José dos Campos, Brazil

The present study was designed to explore the correlation between the frequency of micronuclei in Trad-MN, measured across 28 biomonitoring stations during the period comprised between 11 of May and 2 of October, 2006, and adjusted mortality rates due to cardiovascular, respiratory diseases and cancer in Sao José dos Campos, Brazil, an area with different sources of air pollution. For controlling purposes, mortality rate due to gastrointestinal diseases (an event less prone to be affected by air pollution) was also considered in the analysis. Spatial distribution of micronuclei frequency was determined using average interpolation. The association between health estimators and micronuclei frequency was determined by measures of Pearson's correlation. Higher frequencies of micronuclei were detected in areas with high traffic and close to a petrochemical pole. Significant associations were detected between micronuclei frequency and adjusted mortality rate due to cardiovascular diseases (r = 0.841, p = 0.036) and cancer (r = 0.890, p = 0.018). The association between mortality due to chronic obstructive pulmonary diseases was positive but did not reach statistical significance (r = 0.640, p = 0.172), probably because of the small number of events. Gastrointestinal mortality did not exhibit significant association with micronuclei frequency. Because the small number of observations and the nature of an ecological study, the present findings must be considered with caution and considered as preliminary. Further studies, performed in different conditions of contamination and climate should be done before considering Trad-MN in the evaluation of human health risk imposed by air pollutants.     

Chemical,biological, and ecotoxicological assessment of pesticides and persistent organic pollutants in the Bahlui River,Romania

Background, aim, and scope

Current knowledge on environmental impacts of industrial activities in Romania, particularly persistent organic pollutants (POPs), indicates that environmental standards of the European Union are not systematically met. In our study area, additional sources of POPs are agriculture and domestic wastes. Very scarce information is available upon environmental contaminations and effects. In the present study, we investigated the chemical pollution and their eventual impact on the ecosystem by measuring POPs and by using biological indicators of pollution.

Materials and methods

The survey was carried out at six main sample sites along the Bahlui River. Sediments were chemically analysed for their content in polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs)—hexachlorocyclohexanes (HCHs) isomers and the dichlorodiphenyl trichloroethane (DDT) family. River water was biologically monitored at the level of phytoplankton and benthic invertebrates’ communities. Water samples from six locations have been analyzed for algal species composition and correspondence to various water quality indices. Biological samples have been taken from the same locations so as to calculate the macroinvertebrate indices. In the most polluted areas, as revealed by previous methods, toxicity was tested by exposing the green alga Pseudokirchneriella subcapitata and the cladoceran Daphnia magna to various dilutions of water sample.

Results

Important concentrations of POPs were identified only in sediments at river mouths (sites S5 and S6). Along the year, the sum of PCB concentrations ranged between 3 and 10 ng/g dw (S5), and between 4 and 26 ng/g dw (S6). Concentration of HCHs ranged between 0.4 and 3 ng/g dw (both S5 and S6) with a higher contribution of the gamma-HCH (30–70%), followed by beta-HCH (20–50%). The beta-HCH isomer was found at lower concentrations or even not detected in outer city sites. DDTs were found at higher concentrations than HCHs and ranged between 0.18 and 4 ng/g dw (S5) and between 0.56 and 18 ng/g dw (S6). The parent compound, p,p′-DDT, could be detected only in low concentrations (up to 5 ng/g dw) and contributed with less than 30% to the sum of DDTs in sediment. The principal contributors of the ΣDDTs in sediment were p,p′-DDE, and p,p′-DDD. The o,p′-DDD and DDT isomers were minor contributors to the sum of DDT. PAHs were found at higher concentrations than DDTs and ranged between 6 and 36 ng/g dw (S5) and between 36 and 155 ng/g dw (S6). Fluoranthene was predominant (up to 40%), followed by phenantrene (up to 30%), naphthalene (up to 35%), and benzo-(g,h,i)-perylene (up to 23%). The saprobity index and the diatom index increased from springs to river mouth, indicating a decrease in the water quality, but within the limits of moderate pollution. The saprobity index varied between 1.99 at spring to 2.70 at mouth. The diatom index varied from 3.48 to 3.14. The species’ richness in phytoplankton has a less clear pattern along the river, but in general, it appears to be negatively influenced by pollution. At the level of biological consumer species, the analyses of the macroinvertebrates confirm the situation and the tendency shown with algae. In addition, the Shannon–Wiener index, the Pielou evenness index, and the McNaughton dominance index indicate a peculiar pattern: invertebrate communities appear to a have a more stable structure along the river, with visible shifts at springs and at river mouths. Water toxicity testing indicates low toxicity of river waters around the city of Iasi, with two notable exceptions: the point pollution at the domestic wastewater treatment discharge and at the old open-air deposit of domestic solid wastes. Another important result was that tested algae appeared to be more readily affected than tested cladoceran: EC₅₀ (percent effluent) was 16 in algae and 28 in cladocerans. The slope of toxic effect was also much steeper in cladocerans (6) than in algae (1.8), which means that the toxic effect is more sudden on the tested invertebrates than on the tested algae.

Discussion

Pollutant concentrations reported herein are lower or similar than those reported for the sediments by earlier studies (RIZA 2000; Dragan et al., Int J Environ Anal Chem 86:833–842, 2006). Ratios of individual PAH compounds indicate important pyrolytic inputs and suggest that PAHs in the area are derived from the combustion of fossil fuels. Biologically, the waters appear to be beta-mesosaprobic towards alpha-mesosaprobic according to the saprobic index classification and undergo moderate pollution according to the diatom index classification. Water quality decreases from springs to river mouths. Algal species richness index has a less clear pattern along the river. Water toxicity is low, but certain sources of point pollution require increased attention.

Conclusions

The water quality is better than expected, probably because of the drop in pollution intensity following the collapse of local agricultural and industrial activity following the fall of communism in 1989. Nevertheless, further studies will be needed to confirm and refine our results. While this study draws no strident alarm, it appeals for high attention, particularly because the economic activity in the area is expected to increase.

Recommendations and perspectives

Future close monitoring will be necessary for insuring compliance with the Water Framework Directive, and for refining standards and understanding of the local situation, but with relevance for the wider international community. On the basis of the situation described in the present study, we recommend that future studies dedicate specific efforts to point pollution and effluent toxicity, particularly around the city of Iasi. For a better understanding of pollution and its effects, we recommend pursuing the type of multidisciplinary investigations proposed by the present study: chemical, ecotoxicological, and ecological. We also recommend that new methods should be developed and/or refined, like the empirical determination of partitioning coefficients in water and soils, process-based toxicity methods in ecotoxicological assessments, searching for interactions between pollution, producers, and consumers in aquatic ecosystems. We also recommend preference for cheaper survey methods, as these will be more applicable locally.