A large scale survey of trace metal levels in coastal waters of the Western Mediterranean basin using caged mussels (Mytilus galloprovincialis)

Abstract

A large scale study of trace metal contamination (Hg, Cd, Pb and Ni) by means of caged mussels Mytilus galloprovincialis was undertaken along the coastal waters of the Western Mediterranean Sea within the context of the MYTILOS project. Individual mussels from an homogeneous population (shell size 50 ± 5 mm) obtained from an aquaculture farm were consecutively caged and deployed at 123 sites located in the Alborán, North-Western, South-Western and Tyrrhenian sub-basins for 12 weeks (April-July) in 2004, 2005 and 2006. After cage recoveries, both the metal content in the whole mussel tissue and the allometric parameters were measured. Statistical analysis of the datasets showed significant differences in concentrations between sub-basins for some metals and mussel condition index (CI). Linear regression models coupled to the CI were revisited for the data adjustment of certain trace metals (Hg, Cd and Ni), and four level categories were statistically derived to facilitate interregional comparison. Seawater masses surrounding coastal areas impacted by run-off from land mineralised coasts and industrial activities displayed the highest concentration ranges (Hg: 0.15-0.31 mg kg(-1) dw; Cd: 1.97-2.11; Ni: 2.18-3.20 and Pb: 3.1-3.8), although the levels obtained in most of the sites fitted within moderate or low categories, and they could be considered as baseline concentrations. However, few sites considered little-influenced by human activities, at present, showed high concentrations of Cd, Ni and Pb, which constitute new areas of concern. Overall, the use of active biomonitoring (ABM) approach allowed to investigate trace metal contamination in order to support policy makers in establishing regional strategies (particularly, with regard to the European Marine Strategy Directive).

The effect of size, weight, body compartment, sex and reproductive status on the bioaccumulation of 19 trace elements in rope-grown Mytilus galloprovincialis

“…Cr, Ni, Cu, Zn, Cd, As and Pb Cr, Ni, Cu, Zn, Cd, As and Pb concentrations in rope-grown mussels from the Diane pond were within the range of values measured in the Mediterranean, notably by French mussel watch programs (RINBIO, 2001;Andral et al, 2004;RNO, 2006;Benedicto et al, 2011). For example, Cd (0.374 ± 0.131), Pb (0.336 ± 0.192) and Ni (1.41 ± 0.54) concentrations were very low to moderate when compared to 123 sites in the western Mediterranean basin (mean levels for Cd = 1.33, Pb = 1.40, Ni = 1.10) surveyed with caged mussels between years 2004 and 2006 (Benedicto et al, 2011).…”

“…Cr, Ni, Cu, Zn, Cd, As and Pb Cr, Ni, Cu, Zn, Cd, As and Pb concentrations in rope-grown mussels from the Diane pond were within the range of values measured in the Mediterranean, notably by French mussel watch programs (RINBIO, 2001;Andral et al, 2004;RNO, 2006;Benedicto et al, 2011). For example, Cd (0.374 ± 0.131), Pb (0.336 ± 0.192) and Ni (1.41 ± 0.54) concentrations were very low to moderate when compared to 123 sites in the western Mediterranean basin (mean levels for Cd = 1.33, Pb = 1.40, Ni = 1.10) surveyed with caged mussels between years 2004 and 2006 (Benedicto et al, 2011). Cr (0.554 ± 0.320), Cd and Pb were in the low range of concentrations when compared to 97 mussel cages immersed in year 2000 along the French Mediterranean coasts (mean levels for Cr = 1, Cd = 0.9, Pb = 1 and As = 20, Ni = 2, Cu = 4.1) and in the intermediate range for As (31.2 ± 6.1), Ni (1.41 ± 0.54) and Cu (4.82 ± 1.50); Zn (72.6 ± 33.6) concentrations were half the mean stable value measured in this area (Zn = 148.3;RINBIO, 2001;Andral et al, 2004).…”

“…and biological processes (Bruland and Lohan, 2003). Natural continental runoff and atmospheric deposition of TEs to the oceans (Nriagu, 1989(Nriagu, , 1990Bruland and Lohan, 2003) can be dramatically increased in coastal and estuarine waters due to anthropogenic activities such as urbanization, industry, agriculture or mining (Laubier, 2005;Fernandez et al, 2007;Benedicto et al, 2011). TEs are moreover considered as non-degradable pollutants (Navratil and Minarik, 2011;Pan and Wang, 2012); this persistent character can thus alter, sometimes quite strongly, their natural biogeochemical balance in contaminated environments (Doney, 2010).…”

High metal contents in the fan mussel <em>Pinna nobilis</em> in the Balearic Archipelago (western Mediterranean Sea) and a review of concentrations in marine bivalves (Pinnidae)

“…Many studies on the occurrence of metals in different species and habitats of the Mediterranean Sea have been investigated primarily using the bivalve mollusc Mytilus galloprovincialis (Andral et al 2004, Deudero et al 2009, Benedicto et al 2011) and benthic invertebrate species such as Venus verrucosa, Litophaga litophaga, Ostrea edulis and Chamelea gallina (Deudero et al 2007). Similarly, following the transport, distribution and fate of metal species in the marine environment, many benthic organisms could accumulate them and also be targeted as sentinels of metal contamination.…”

“…accumulate metals either directly from dissolved concentrations in the water column or indirectly via ingestion of metal-bounded suspended particles from the surrounding environment. Bivalves have been shown to be valuable 'sentinel organisms' because of their limited metabolic capacity of metal excretion and their worldwide distribution (Goldberg 1975, Goldberg andBertine 2000), and they have therefore been used to monitor and assess coastal pollution for decades (O'Connor and Beliaeff 1995, O'Connor and Launstein 2006, Benedicto et al 2011, Besada et al 2014, Neira et al 2015.…”