Occurrence of persistent organic pollutants in sediments and biota from Portugal versus European incidence: A critical overview

Persistent organic pollutants (POPs) are widespread compounds, such as organohalogenated compounds, polycyclic aromatic hydrocarbons (PAHs) and pesticides, which can be found in all types of environmental compartments. Their presence in the aquatic environment is a worldwide problem, with emphasis on sediments which act as depository and consequently as a source of hydrophobic, recalcitrant and harmful compounds. Besides, these pollutants might affect the reproduction and mortality of living organisms, diverging in their potential to bioaccumulate in tissues. The present paper aims to review the occurrence of POPs in sediments and biota from the coastal, estuarine and river areas of Portugal. The list of the studied compounds comprises organohalogenated compounds, PAHs, organometallic compounds, pesticides, sterols, fatty acids and pharmaceutical compounds. The contamination of sediments by various pollutants is presented, such as PAHs up to 7,350 ng g^?1 found in Sado estuary and polychlorinated biphenyls up to 62.2 ng g^?1 in the case of sediments collected in Ria de Aveiro. The occurrence of these persistent toxic substances in sediments demonstrates aquatic contamination from agricultural, industrial and urban discharges and the concern about the potential risks to aquatic organisms, wildlife and humans. In fact, several classes of POPs have also been found in biota, such as polychlorinated biphenyls up to 810.9 ng g^?1 in sentinel fish from the Douro River estuary and pesticides in bivalves from the Sado River estuary. The importance of further systematic research on sediments and biota is here highlighted to compare the contamination of these two reservoirs; to assess their spatial and temporal variation; and to determine other classes of POPs that were not investigated yet (e.g., industrial compounds, estrogens and many classes of pharmaceuticals).     

Ecosystem services and biodiversity conservation under forestation scenarios: options to improve management in the Vez watershed,NW Portugal

Ensuring forest protection and the delivery of forest ecosystem services is a central aim of the European Union’s biodiversity strategy for 2020. Therefore, accurate modelling and mapping of ecosystem services as well as of biodiversity conservation value is an important asset in support of spatial planning and policy implementation. The objectives of this study were to analyse the provision of the multiple ecosystem services under two forestation scenarios (eucalyptus/pine vs. oak) at the watershed scale and to evaluate their possible trade-offs with the biodiversity conservation value. The Vez watershed, in northwest Portugal, was used as case study area, in which soil and water assessment tool (SWAT) was applied to simulate the provision of hydrological services, biomass and carbon storage services. Biodiversity conservation value was based on nature protection regimes and on expert judgement applied to a land cover map. Results indicated large provision of ecosystem services in the high and low mountain sub-basins. The overall performance for water quantity and timing is better under the shrubland and oak forest scenarios, when compared to the eucalyptus/pine forest scenario, which perform better for flood regulation and erosion control services, especially in the low mountain sub-basin. The current shrubland dominated cover also shows good performance for the control of soil erosion. The oak scenario is the one with less trade-offs between forest services and biodiversity conservation. Results highlight SWAT as an effective tool for modelling and mapping ecosystem services generated at the watershed scale, thereby contributing to improve the options for land management.     

Distributed,high-resolution modelling of critical source areas for erosion and phosphorus losses

Phosphorus losses from arable land need to be reduced to prevent eutrophication of surrounding waters. Owing to the high spatial variability of P losses, cost-effective countermeasures need to target parts of the catchment that are most susceptible to P losses. Field surveys identified critical source areas for overland flow and erosion amounting to only 0.4–2.6 % of total arable land in four different catchments in southern Sweden. Distributed modelling using high-resolution digital elevation data identified 72–96 % of these observed erosion and overland flow features. The modelling results were also successfully used to predict occurrence of overland flow and rill and gully erosion in a catchment in central Sweden. Such exact high-resolution modelling allows for accurate placement of planned countermeasures. However, current legislative and environmental subsidy programmes need to change their approach from income-loss compensation to rewarding high cost effectiveness of implemented countermeasures.     

Environmental risk assessment in five rivers of Parana River basin,Southern Brazil,through biomarkers in Astyanax spp.

Environmental Science and Pollution Research - In the current study, water quality of five river sites in Parana River basin (Brazil), utilized for public water supply, was assessed through a set...     

Distribution and human health risk assessment of PAHs in four fish species from a SW Atlantic estuary

Environmental Science and Pollution Research - The aim of this study is to assess—for the first time—the concentration of the 16 polycyclic aromatic hydrocarbons (PAHs) in the muscle...     

Voltammetric detection of trifluralin in tap water,fruit juice,and vegetable extracts in the presence of surfactants

This study describes a novel electrochemical method to determine the herbicide trifluralin in samples of water, fruit juice, and vegetable extracts in the presence of surfactants, using a glassy carbon electrode (GCE). In acidic media, trifluralin was irreversible on the glassy carbon electrode surface at ?0.5 V vs. Ag/AgCl. Surfactant presence on the electrode–solution interface modified current intensities and shifted the reduction peak potential of trifluralin. Different types of surfactant and their concentrations were investigated. The anionic surfactant significantly enhanced the peak current intensity of trifluralin. Under optimal analytical conditions, an analytical curve was obtained in the concentration range of 0.48–32.20 µM. The limits of detection and quantification were estimated at 0.031 and 0.104 µM, respectively. The method was successfully applied to quantify trifluralin in samples of water, orange and tomato juice, and green pepper, carrot, and onion extracts, with recovery rates of 97.9–102.1%. The results were in good agreement with those obtained using high-performance liquid chromatography, indicating that the proposed electrochemical method can be employed to quantify trifluralin in various types foods, with sensitivity, specificity, selectivity and reproducibility.     

Influence of toxic cyanobacteria on community structure and microcystin accumulation of freshwater molluscs

Community structure and microcystin accumulation of freshwater molluscs were studied before and after cyanobacterial proliferations, in order to assess the impact of toxic blooms on molluscs and the risk of microcystin transfer in food web. Observed decrease in mollusc abundance and changes in species richness in highly contaminated waters were not significant; however, relative abundances of taxa (prosobranchs, pulmonates, bivalves) were significantly different before and after cyanobacterial bloom. Pulmonates constituted the dominant taxon, and bivalves never occurred after bloom. Microcystin accumulation was significantly higher in molluscs from highly (versus lowly) contaminated waters, in adults (versus juveniles) and in pulmonates (versus prosobranchs and bivalves). Results are discussed according to the ecology of molluscs, their sensitivity and their ability to detoxify.     

AnSBBR applied to the treatment of wastewater from a personal care industry: Effect of organic load and fill time

The objective of this work was to study the technological feasibility of treating wastewater from a personal care industry (PCI-WW) in a mechanically stirred anaerobic sequencing batch biofilm reactor (AnSBBR) containing immobilized biomass on polyurethane foam. An assessment was made on how system efficiency and stability would be affected by: increasing organic load; supplementation of nutrients and alkalinity; and different feed strategies. The AnSBBR operated with 8-h cycles, stirring speed of 400 rpm, temperature of 30 °C, and treated with 2.0 L wastewater per cycle. First the efficiency and stability of the AnSBBR were studied when submitted to an organic loading rate (OLR) of 3.1–9.4 gCOD/(L d), and when the PCI-WW was supplemented with nutrients (sucrose, urea, trace metals) and alkalinity. The AnSBBR was shown to be robust and presented stability and removal efficiency exceeding 90%. At an OLR of 12.0 gCOD/(L d) efficiency became difficult to maintain due to the presence of commercial cleansers and disinfectants in the wastewater lots. In a subsequent stage the AnSBBR treated the wastewater supplemented with alkalinity, but with no nutrients at varying feed strategies and maintaining an OLR of approximately 9.0 gCOD/(L d). The first strategy consists of feeding 2.0 L of the influent batchwise [OLR of 9.4 gCOD/(L d)]. In the second 1.0 L of influent was fed-batchwise and an additional 1.0 L was fed fed-batchwise [OLR of 9.2 gCOD/(L d)], i.e., in relation to the first strategy the feed volume was maintained but supplied in different periods. In the third strategy 1.0 L of treated effluent was maintained in the reactor and 1.0 L of influent was fed fed-batchwise [OLR of 9.0 gCOD/(L d)], i.e., in relation to the first strategy the feed volume was different but the feed period was the same and the OLR was maintained by increasing the influent concentration. Comparison of the first and second strategies revealed that organic matter removal efficiency was unaffected (exceeding 90%). The third strategy resulted in a reduction in average removal efficiency from 91 to 83% when compared to the first one. A kinetic study resulted in first order kinetic parameters ranges from 0.42 to 1.46 h⁻¹ at OLRs from 3.1 to 12.0 gCOD/(L d), respectively, and the second feed strategy [OLR of 9.2 gCOD/(L d)] was shown to be the most favorable.     

Artisanal fisheries of the Itaparica reservoir,São Francisco River,Brazil: socioeconomic profile,environmental dynamics,and management recommendations

Currently, artisanal fisheries in fresh water reservoirs have been losing ground to commercial fish farming and a great deal of fishery resources are being threatened by human interventions, such as reservoir management and increasing net-cage aquaculture. This study aims to understand the impacts of environmental changes on fishery resources and analyse the migratory fish breeding season as a missing link for fishery management in the semi-arid area of the São Francisco River Basin. Among the 870 fishermen operating in the Pernambuco part of the Itaparica Reservoir, 10% were interviewed and affirmed that fish stocks have been compromised due to the closed fishing period’s incoherence, exotic species insertion, and changes to the river flow caused by reservoir construction and operation. A significant correlation was observed between the Reproductive Activity Index (RAI) and precipitation (p?=?0.745) as well as between the RAI and the river’s flow (p?=??0.909). This shows how important it is to consider both the semi-arid climate setting and reservoir operation in determining the closed period which should safeguard fish reproduction. Monitoring the fish reproduction period and research on the reproductive biology of native fish species is needed in the São Francisco River Basin’s different stretches in order to guarantee valuable fish stocks and fisheries maintenance. Integrated action between the fish resource users, civil society, and federal bodies/agencies is essential in order to mitigate impacts and improve fish production systems, not only in Brazil, but in other regions experiencing a similar scenario.     

Influence of the composition of the initial mixtures on the chemical composition,physicochemical properties and humic-like substances content of composts

The influence of the proportion of C- and N-rich raw materials (initial C/N ratio) and bulking agent on the chemical functional groups composition, humic-like substances (HS-like) content and physicochemical properties of composts was assessed. To achieve these goals, seven initial mixtures (BA1–6 and C1) of dog food (N-rich raw material) were composted with wheat flour (C-rich raw material). Composts were analyzed in terms of chemical functional groups, physicochemical, maturity and stability parameters.The C-rich raw material favored the formation of oxidized organic matter (OM) during the composting process, as suggested by the variation of the ratios of the peaks intensity of FT-IR spectra, corresponding to a decrease of the polysaccharides and an increase of aromatic and carboxyl-containing compounds. However, although with high proportion of C-rich raw material, mixtures with low initial C/N seems to have favored the accumulation of partially oxidized OM, which may have contributed to high electrical conductivity values in the final composts. Therefore, although favoring the partial transformation of OM into stabilized HS-like, initial mixtures with high proportion of C-rich raw material but with low initial C/N led to unstable composts.On the other hand, as long as a high percentage of bulking agent was used to promote the structure of biomass and consequently improve of the aeration conditions, low initial C/N was not a limiting factor of OM oxidation into extractable stabilized humic-like acids.