DPSIR framework for assessing mercury pollution in Ria de Aveiro, Portugal

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The DPSIR framework aims to assess the Driving forces and Pressures on an area, the State of the environment and the Impacts these forces have and the Responses that are undertaken. In this case study the DPSIR framework is used to assess the impact of mercury pollution in the Ria de Aveiro, Portugal.

The study area

Ria de Aveiro is a shallow well-mixed coastal lagoon on the northwestern coast of Portugal (40º38’N, 8”45’W) connected to the sea by a single channel (1.3 km long, 350 m wide and 20 m deep). It forms a complex system characterized by narrow channels and extensive intertidal zones, covering an area of approximately 47 km2. Excluding the dragged navigation channels the systems mean depth is about 1m, with a mean tidal range of 0.6-3.2 m. The hydrology is essentially dominated by tidal forcing, responsible for a strong mixture of the water masses. The major sources of freshwater inflow are the Vouga and Antuã rivers, followed by the Boco river and a small system of ponds and river (e.g. Pato et al., 2008, Pereira et al., 2008a).

In between 1950 and 1990, Ria de Aveiro received continuous discharges of mercury, mainly from a chlor-alkali plant, located in a chemical-complex industry nearby Estarreja. Subsequently mercury rich effluents dispersed in the system, mainly in the Estarreja Channel and in the Laranjo Bay due to its semi enclosed characteristics (Hall, et al., 1987, Pereira et al., 1998a, 1998b, Pereira et al., 2008a). In the last decade, the mercury discharge diminished considerably, being nowadays within the regulatory levels (50 µg L-1, the limit value for discharges from chlor-alkali electrolysis industry, in accordance with Directive 82/176/EEC). However, mercury concentrations in the surface sediments of some areas of the Ria are still higher than pre-industrial levels, namely in the Laranjo bay (a shallow area with 2 km2) with values in the range of 2.5 – 51.7 µg Hg g-1 (Coelho et al., 2005).Concerns now exist about the future environmental health of the Ria and attempts have been made to understand the processes affected by the historical load of mercury (e.g. Abreu et al., 1998, Pato et al., 2008a). Therefore, several research studies have been carried out in Ria de Aveiro during the latest years concerning sediments, water, biota and soils (Pereira et al., 2008a).

DPSIR framework

Relevant Driving forces and Pressures on the Ria de Aveiro, the consequent State of the environment and its Impacts, and the Responses undertaken, and of interlinkages between each of these elements

Driving forces

(e.g. Hall et al., 1987, Pereira et al., 2008a)

  • Industry (Historical pollution)
  • Agricultural activities
  • Households-waste water treatment


(e.g. Pereira et al., 2008a)

  • Discharges from industrial point source (main source)
  • Release of mercury pollution (Hg) from historical contaminated sediments (Duarte et al., 1991, Ramalhosa et al., 2006)
  • Solid waste management (disposal)
  • Loads to surface waters by diffuse sources (drainage, transport, accidental spills)
  • Leaching from agricultural areas
  • Atmospheric deposition


  • Increase concentration of Hg in sediments (e.g. Ramalhosa et al., 2006)
  • Bioaccumulation of Hg and organic Hg in biota, namely:
    • Plankton (Monterroso et al., 2003)
    • Macroalgae (Fucus, Gracilaria and Enteromorpha)(Coelho et al., 2005)
    • Macrofauna (Scrobicularia plana and Carcinus maenas)(Coelho et al., 2006, 2007, 2008, Pereira et al., 2006, Nunes et al., 2008)
    • Fish (e.g. Dicentrarchus labrax, Liza aurata) (Abreu et al., 2000, Guilherme et al., 2008a, b)
    • Salt marshes plants (Halimione portulacoides) (Micaelo et al., 2003, Válega et al., 2008a, b, c, d)
    • Birds (Himantopus himantopus) (Tavares et al., 2004)
  • Hg concentration in the nearshore waters (Pato et al., 2008a, b)
  • Hg concentrations in urban and agricultural soils (Rodrigues et al., 2006, Cachada et al., 2008)


  • Contamination problems in Ria de Aveiro are confined to the Laranjo Basin (e.g. Pato et al., 2008a,b, Pereira et al., 2008).
  • Macroalgal harvesting for human uses and human consumption of mussels and crabs from the Laranjo Basin may constitute a risk for human health (Coelho et al., 2006, Pereira et al., 2006, Pereira et al., 2008a).


References and external links

Cachada A., Rodrigues, S.M., Mieiro, C., Ferreira da Silva, E., Pereira, E. & Duarte, A.C. (2008) Controlling factors and environmental implications of mercury contamination in urban and agricultural soils under a long term influence of a chlor-alkali plant in North-West Portugal. Environmental Geology. http://dx.doi.org/10.1007/s00254-008-1284-2

Coelho, J.P., Reis, A.T, Ventura, S., Pereira, M.E., Duarte, A.C., Pardal, M.A. (2008) Pattern and pathways for mercury lifespan bioaccumulation in Carcinus maenas. Marine Pollution Bulletin, 56, 1104–1110. http://dx.doi.org/10.1016/j.marpolbul.2008.03.020

Guilherme, S. Válega, M., Pereira, M.E., Santos, M.A., Pacheco, M. (2008a) Erythrocytic nuclear abnormalities in wild and caged fish (Liza aurata) along an environmental mercury contamination gradient. Ecotoxicology and Environmental Safety, 70, 411–421. http://dx.doi.org/10.1016/j.ecoenv.2007.08.016

Guilherme, S. Válega, M., Pereira, M.E., Santos, M.A., Pacheco, M. (2008b) Antioxidant and biotransformation responses in Liza aurata under environmental mercury exposure – Relationship with mercury accumulation and implications for public health. Marine Pollution Bulletin, 56, 845–859. http://dx.doi.org/10.1016/j.marpolbul.2008.02.003

Lopes C.B., Coimbra J., Otero M., Pereira E., Lin Z., Rocha J., Duarte A.C. (2008a) Uptake of Hg2+ from aqueous solutions by microporous titano- and zircono-silicates. Quimica Nova. 31, 2, 321-325. http://quimicanova.sbq.org.br/qn/qnol/2008/vol31n2/24-AR07095.pdf

Lopes, C.B., Lito, P.F., Otero, M.,. Lin, Z, Rocha, J., Silva, C.M., Pereira, E., Duarte, A.C. (2008b) Mercury removal with titanosilicate ETS-4: Batch experiments and modelling. Microporous and Mesoporous Materials, 115, 98–105. http://dx.doi.org/10.1016/j.micromeso.2007.10.055

Nunes M. Coelho, J.P, Cardoso, P.G., Pereira, M.E., Duarte, A.C., Pardal, M.A. (2008) The macrobenthic community along a mercury contamination in a temperate estuarine system (Ria de Aveiro, Portugal). Science of Totam Environment, 405, 186-194. http://dx.doi.org/10.1016/j.scitotenv.2008.07.009

Pereira M.E., Lillebø A.I., Pato P., Válega M., Coelho J.P., Lopes C., Rodrigues S., Cachada A., Otero M., Pardal M.A., Duarte A.C. (2008a) Mercury pollution in Ria de Aveiro (Portugal): a review of the system assessment. Environment Monitoring and Assessment. http://dx.doi.org/10.1007/s10661-008-0416-1.

Pereira E., Rodrigues S. M., Otero M., Válega M., Lopes C.B., Pato P., Coelho J.P., Lillebø A.I., Pardal M.A., Rocha R., Duarte A.C. (2008b) Evaluation of a proficiency interlaboratory exercise for total mercury in environmental samples: soils, sediments and fish tissue. TrAC, Trends in Analytical Chemistry, 27 (10) 959-970. http://dx.doi.org/10.1016/j.trac.2008.09.00.

Pato P., Lopes, C., Válega, M., Lillebø, A. I., Dias, J. M., Pereira, E. & Duarte, A. (2008a) Mercury fluxes between a coastal lagoon (Ria de Aveiro, Portugal) and the Atlantic Ocean. Estuarine, Coastal and Shelf Science, 76, 787-796. http://dx.doi.org/10.1016/j.ecss.2007.08.010

Pato, P., Válega, M., Pereira, E., Vale, C. & Duarte, A. (2008b) Inputs from a Mercury-Contaminated Lagoon: Impact on the Nearshore Waters of the Atlantic Ocean. Journal of Coastal Research, 24, (2B), 28-38. http://dx.doi.org/10.2112/05-0550.1

Válega, M., Lillebø, A. I., Pereira, M. E., Duarte, A. C. & Pardal, M. A. (2008a) Long-term Effects of Mercury in a Salt Marsh: Hysteresis in the Distribution of Vegetation Following Recovery from Contamination. Chemosphere, 71, 765–772. http://dx.doi.org/10.1016/j.chemosphere.2007.10.013

Válega, M., Lillebø, A. I., Pereira, M. E., Corns, W. T., Stockwell, P. B. Duarte, A. C. & Pardal, M. A. (2008b). Assessment of methylmercury production in a temperate salt marsh (Ria de Aveiro Lagoon, Portugal). Baseline / Marine Pollution Bulletin, 56, 136–162. http://dx.doi.org/10.1016/j.marpolbul.2007.09.029

Válega, M., Lillebø, A.I., Pereira, M.E., Caçador, I., Duarte, A.C. & Pardal, M.A (2008c). Mercury in salt marshes ecosystems: Halimione portulacoides as biomonitor. Chemosphere, 73, 1224–1229, http://dx.doi.org/10.1016/j.chemosphere.2008.07.053

Válega, M., Lillebø, A.I., Caçador, I., Pereira, M.E., Duarte, A.C. and Pardal, M.A (2008d) Mercury mobility in a salt marsh colonised by Halimione portulacoides. Chemosphere, 72, 1607–1613 http://dx.doi.org/10.1016/j.chemosphere.2008.04.007

Coelho, JP, Policarpo, E., Pardal, M.A., Millward, G.E., Pereira, M.E., Duarte, A.C. (2007) Mercury contamination in invertebrate biota in a temperate coastal lagoon (Ria de Aveiro, Portugal). Marine Pollution Bulletin, 54, 475-480. http://dx.doi.org/10.1016/j.marpolbul.2006.11.020

Lopes CB, M Otero, J Coimbra, E Pereira, J Rocha, Z Lin & A. Duarte 2007.Removal of low-concentration Hg2+ from natural waters by microporous and layered titanosilicates. Microporous and Mesoporous Materials. http://dx.doi.org/10.1016/j.micromeso.2007.02.025

Pereira, M.E., S.N. Abreu, J.P. Coelho, C.B. Lopes, M.A. Pardal., C. Vale and A.C. Duarte 2006. Seasonal fluctuations of tissue mercury contents in the European shore crab Carcinus maenas from low and high contamination areas (Ria de Aveiro, Portugal). Marine Pollution Bulletin, 52: 1450 – 1457. http://dx.doi.org/10.1016/j.marpolbul.2006.05.006

Coelho JP, M Rosa, ME Pereira, A Duarte & MA Pardal 2006. Pattern and annual rates of Scrobicularia plana mercury bioacumulation in a human induced mercury gradient (Ria de Aveiro, Portugal). Estuarine, Coastal and Shelf Science 69:629-635. http://dx.doi.org/10.1016/j.ecss.2006.05.027

Ramalhosa E, SR Segade, E Pereira, C Vale & A Duarte 2006. Mercury cycling between the water column and surface sediments in a contaminated area. Water Research 40: 2893-2900. http://dx.doi.org/10.1016/j.watres.2006.05.023

Rodrigues S, ME Pereira, L Sarabando, L Lopes, A Cachada, A Duarte. 2006. Spatial Distribution of Total Hg in Urban Soils from an Atlantic Coastal City (Aveiro, Portugal). The Science of the Total Environment, 368:40-46. http://dx.doi.org/10.1016/j.scitotenv.2005.09.088

Válega M, Abreu S, Pato P, Rocha L., Gomes AR, Pereira ME, Duarte AC, 2006. Determination of organic mercury in biota, plants and contaminated sediments using a thermal atomic absorption spectrometry technique, Water, Air, and Soil Pollution 174: 223–234. http://dx.doi.org/10.1007/s11270-006-9100-7

Coelho JP, ME Pereira, A Duarte & MA Pardal 2005. Macroalgae response to a mercury contamination gradient in a temperate coastal lagoon - Ria de Aveiro, Estuarine, Coastal and Shelf Science 65: 492-500. http://dx.doi.org/10.1016/j.ecss.2005.06.020

Carapuça MH, M Válega, E Pereira, A Duarte 2004. Monitoring aci-volatile sulphide by fast scan voltammetric method: application to mercury contamination studies in salt marsh sediments. Analytica Chimica Acta 524:127-131. http://dx.doi.org/10.1016/j.aca.2004.06.009

Tavares PC, Monteiro LR, Lopes RJ, Santos MMC, Furness RW 2004. Intraspecific variation of mercury contamination in chicks of Black-winged Stilt (Himantopus himantopus) in coastal wetlands from Southwestern Europe. Bulletin of Environmental Contamination and Toxicology 72 (3): 437-444. http://dx.doi.org/ 10.1007/s00128-004-0265-8

Micaelo C, Valega M, Vale C, Pereira E, Duarte A, Cacador I 2003. Evidence for concentration of anthropogenic mercury in salt marsh sediments. Ciencias Marinas 29 (4): 447-456. http://rcmarinas.ens.uabc.mx/index.php/cmarinas/article/view/129/106

Monterroso P, Abreu SN, Pereira E, Vale C, Duarte AC 2003. Estimation of Cu, Cd and Hg transported by plankton from a contaminated area (Ria de Aveiro). Acta Oecologica-International Journal of Ecology 24: S351-S357. http://dx.doi.org/10.1016/S1146-609X(03)00033-X

Abreu SN, Pereira E, Vale C, Duarte AC 2000. Accumulation of mercury in sea bass from a contaminated lagoon (Ria de Aveiro, Portugal). Marine Pollution Bulletin 40 (4): 293-297. http://dx.doi.org/10.1016/S0025-326X(99)00187-3

Pereira ME, Duarte AC, Millward GE, Vale C, Abreu SN 1998. Tidal export of particulate mercury from the most contaminated area of Aveiro's Lagoon, Portugal. Science of the Total Environment 213 (1-3): 157-163. http://dx.doi.org/10.1016/S0048-9697(98)00087-4

Pereira ME, Duarte AC, Millward GE, Abreu SN, Vale C 1998. An estimation of industrial mercury stored in sediments of a confined area of the Lagoon of Aveiro (Portugal). Water Science and Technology 37 (6-7): 125-130. http://dx.doi.org/10.1016/S0273-1223(98)00191-7

Abreu SN, Pereira ME, Duarte AC 1998. The use of a mathematical model to evaluate mercury accumulation in sediments and recovery time in a coastal lagoon (Ria de Aveiro, Portugal).Water Science and Technology 37 (6-7): 33-38. http://dx.doi.org/10.1016/S0273-1223(98)00179-6

Duarte AC, Pereira ME, Oliveira JP, Hall A 1991. Mercury desorption from contaminated sediments. Water Air and Soil Pollution 56: 77-82. http://dx.doi.org/ 10.1007/BF00342262

Hall A, Duarte AD, Caldeira MTM, Lucas MFB 1987. Sources and sinks of mercury in the coastal lagoon of Aveiro, Portugal. Science of the Total Environment 64 (1-2): 75-87. http://dx.doi.org/10.1016/0048-9697(87)90123-9

The main author of this article is Ana Isabel Lillebø
Please note that others may also have edited the contents of this article.

19 Dec. 08, Lillebø AI, AC Duarte, E Pereira, M Otero, S Rodrigues, M Válega, JP Coelho, C Lopes, P Pato, Department of Chemistry, CESAM – Centre of Environmental and Marine Studies, University of Aveiro, Portugal. lillebo@ua.pt, aduarte@ua.pt, eduper@ua.pt, , marta.otero@ua.pt, srodrigues@ua.pt, mvalega@ua.pt, jpcoelho@ua.pt, claudia.b.lopes@ua.pt, pedro.pato@ua.pt.