Research Centre for Natural Resources, Environment and Society - CERNAS

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Heavy metal and PCB spatial distribution pattern in sediments within an urban catchment: contribution of historical pollution sources

Publication . Ferreira, Célia; Pato, Rosinda L.; Varejão, Jorge B.; Tavares, Alexandre O.; Ferreira, Antonio J. D.

Purpose This work analyzes polychlorinated biphenyl (PCB) and heavy metal contamination in fluvial sediments and soils in an urban catchment, according to the geo-accumulation index and to soil and sediment quality guidelines. The catchment is located in Coimbra, Portugal, being affected by frequent flooding, and its main stream is a tributary to one of the major rivers in Portugal (Mondego). Given the presence of industrial activities over time, some inputs of pollutants are expected, but so far, the legacy of historic pollution in this catchment has not yet been investigated. Materials and methods Twenty-five samples were collected from nine sampling sites at the depths of 0–20, 20–40 and 40– 60 cm (to provide a historic perspective) along longitudinal profiles (streamlines) and in soils downstream of pollution sources. These samples were analyzed for six heavy metals (Cu, Cr, Pb, Cd, Zn, Ni), organic carbon, pH and ten PCBs (IUPAC numbers 28, 30, 52, 101, 138, 153, 166, 180, 204, 209). Results and discussion Total PCB concentrations ranged 0.47–5.3 ng g−1 dry weight (dw), and levels increase from the bottom to the top layers, suggesting an increased input over the last 100 years. PCB congener distribution shows the dominance of hexachlorobiphenyls, especially PCB138, suggesting the existence of local sources. PCB levels did not exceed sediment quality levels, placing sediments/soil under class 1 (not contaminated) or class 2 (trace contamination) with respect to PCB. All six metals exceeded the lowest effect level for sediment quality criteria, and three (Cd, Pb and Zn) largely exceeded the clean levels for dredged materials, placing sediments in class 5 (heavily contaminated). Sampling site S1 presented the highest concentrations of Zn, Pb and Cd, and historic vehicle traffic was identified as the most likely source, given the vertical and horizontal profiles. Conclusions High levels of Pb, Cd and Zn were found in fluvial sediments at some locations of the Loreto catchment, likely from historic traffic sources. This urban area is frequently affected by flooding events and is currently being subject to urban redevelopment. During these events/actions, historic pollutants in the sediments might surface and be redistributed, impacting the downstream ecosystem of the major Mondego River or increasing the risk of exposure of the urban population.

2016Journal article

Restricted access

Roads as sources of heavy metals in urban areas. the Covões Catchment experiment, Coimbra, Portugal

Publication . Ferreira, António J. D.; Soares, Daniel; Serrano, Luís M .V.; Walsh, Rory P. D.; Ferreira, Célia; Ferreira, Carla S. S.

Purpose This work studies the implications of different traffic patterns for heavy metal and solid pollution generation processes following rainfall events with contrasting antecedent meteorological conditions, at a periurban catchment. The aim is to provide information on the pollution processes and their potential environmental impacts for urban areas. Materials and methods Seven campaigns were performed covering winter, spring, and summer conditions, for rainfall events with different antecedent conditions. Four types of roads were monitored: low traffic, average traffic, heavy traffic with demanding driving situations (break and turning), and heavy traffic with high vehicle speed (motorway profile). Samples were taken at the beginning, middle and end of the events to measure within event variation in concentration. Analytical standard procedures were used to quantify pH, conductivity, turbidity, total solids, volatile solids, suspended solids, volatile suspended solids and heavy metals (Cd, Cu, Pb and Zn) in the total and dissolved forms (as to infer the particulate fraction), namely copper, zinc, cadmium and lead. Results and discussion The collected data show a direct relation among the number of vehicles and/or the driving manoeuvres performed by them and the amount of solids and heavy metals present in the wash out overland flow collected. An important fraction of the heavy metals is washed off in the particulate form, which represents an increased problem since the road overland flow is directed to green/brown areas and for the local aquatic ecosystems. Maximum copper values recorded exceed 0.6 mh L−1 , zinc exceeds 5 mg L−1 , lead 0.1 mg L−1 and cadmium 0.01 mg L−1 . Values are higher after long dry spells and reduce concentration throughout the rainfall events. Conclusions An important part of the heavy metals (with relevance for zinc and lead) are washed off in the particulate form, pollutants are typically related to the amount of traffic, and especially to the existence of driving manoeuvres. The summer events show the highest values, due to the accumulation of pollutants during the long dry spells.

2016Journal article

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Phytophthora xalni and phytophthora lacustris associated with common alder decline in Portugal

Publication . Kanoun-Boulé, M.; Vasconcelos, T.; Gaspar, J.; Vieira, S.; Ferreira, Célia; Husson, C.

Since the early 1990s, an emerging disease induced by the highly aggressive oomycete Phytophthora 9alni has caused widespread alder decline across Europe. In parallel, P. lacustris, a recently described species associated with riparian habitats, has been subject of increasing interest. A field survey conducted in 2014 showed high mortality rates in alder stands located in the riparian gallery along two rivers in Central Portugal. The pathogens isolated from necrotic alder stem base during this study were identified as P. 9alni and P. lacustris. This paper is the first to report the occurrence of P. lacustris in Portugal and presents the first finding of P. 9alni affecting mature trees in natural ecosystems located in Central Portugal.

2016Journal article

Restricted access

Recolha seletiva de embalagens na região litoral Centro de Portugal: sistema atual vs novas soluções

Publication . Oliveira, Verónica; Vaz, João; Neves, Anita; Sousa, Vítor; Ferreira, Celia

2017-12Book part

Open access

Dataset of socio-economic and waste collection indicators for Portugal at municipal level

Publication . Oliveira, Verónica; Sousa, Vitor; Ferreira, Célia

This data article presents demographic, socio-economic and wasterelated data at municipal level for Portugal. The dataset includes raw data collected from 4 main sources: (i) the annual reports of waste management companies; (ii) the database of the Portuguese water, sanitation and waste regulatory entity; (iii) the Portuguese Environmental Agency; and (iv) national statistical data. Relevant indicators for waste generation and for the separate collection of waste are proposed and calculated using the raw data. The dataset comprises municipalities with high, medium and low separate collection yields, providing socio-economic and waste infrastructures data that can be used for benchmarking. The dataset can also be used to define a baseline against which the progress of the collection of packaging waste can be assessed over time, or else serve as input to mathematical models predicting waste generation and collection. Moreover, data can serve as the base to calculate new waste-related indicators. In addition to being a valuable input to the waste topic, the dataset can also be used in a large range of other topics where demographic and socio-economic parameters are relevant. The data presented herein are associated with the research articles “Model for the separate collection of packaging waste in Portuguese low-performing recycling regions” [1] and “Artificial neural network modelling of the amount of separatelycollected household packaging waste” [2].

2019-02Journal article

Open access