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Metals in the European Marine Strategies Legislation: A Challenge for the Managers and Decision-Makers
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Antonio Tovar-Sań chez,* Cira Buonocore, David Roque, and Juliań Blasco ICMAN-Instituto de Ciencias Marinas de Andalucía (CSIC), Campus Universitario Río San Pedro, 11510 Puerto Real, Cádiz, Spain include among others, initial assessments of the current environmental status of national marine waters on the basis of 11 descriptors (such as biodiversity, marine litter, eutrophication, or contaminants); and the development and implementation of monitoring programs and measures designed to achieve or maintain the GES. Thus, the countries have as their main concern ensuring that the levels of certain chemical substances with potentially significant risk to the environment, or to human health, in surface coastal waters do not to give rise to pollution effects (qualitative descriptor 8 in the MSFD). The trace metals Cd, Pb, Hg, Ni, and their compounds, are among the priority elements listed in the Directives 2008/105/EC and 2013/39/EU, which must be routinely measured by each country through monitoring programs for the evaluation of the progress made toward achieving GES in EU’s waters. Here, we analyze the results of the monitoring program in Spain as one of the European countries with the most extensive marine regions in the UE, encompassing Macaronesia, Bay of Biscay and the Iberian Coast, and Western Mediterranean Sea subregions (Figure 1). The information obtained from reported trace metals values in marine waters tend to be he monitoring of trace metals present in surface marine skewed and questionable for a number of reasons, such as waters is a priority as well as a commitment from inadequate sampling among others. It is scientifically European member states aiming to ensure a clean, healthy and recognized that any study in the marine environment which productive marine environmental status. However, the lack of involves the analysis of metals requires clean sampling of the knowledge transfer from the scientific community to the water. With appropriated sampling devices (e.g., towed monitoring program authorities means that the reports of trace sampling devices or metal-free sampling rosettes) it is possible metal values in marine waters are inconclusive and thus of little to obtain a representative sample of the water compartment value. The use of inappropriate sampling systems and of ensuring precise and accurate results even with the most lowanalytical treatments, together with the broad and conservative level trace elements. In order to guarantee minimum proposed reference levels of concentrations, precludes the performance criteria for methods of analysis to be applied by assessment of variations in metal concentrations at environMember Countries when monitoring water status, Directive mental levels that affect the ecological status of the marine 2009/90/EC established technical specifications for chemical ecosystems. analysis and monitoring. However, this Directive does not During the last decades, the protection and conservation of specify anything about sampling techniques, which, according to the scientific community are essential to guarantee reliable the marine environment have being a priority concern for an results of metals in the marine system. Hence, contamination increasing number of governmental and nongovernmental issues can be masking the final reported data and consequently organizations acting through planned managements at national the conclusions about the water status. and international levels. The European Union (EU) has made Another reason is the inappropriate use of analytical great efforts toward this objective and on 17 June 2008, based methods and/or techniques which results in producing on the water Framework Directive (WFD) (Directive 2000/ imprecise data often reported as nondetected concentration. 60/EC), the European Parliament marked a milestone in the For example, the most extensively analytical techniques used EU marine water policy establishing the Marine Strategy for trace metal determination in seawater for the monitoring Framework Directive (MSFD; Directive 2008/56/EC). The programs are the spectrometric, mainly inductively coupled main objective of this MSFD is to protect efficiently the marine plasma mass spectrometry (ICP-MS). Advantages of ICP-MS environment across Europe and to achieve Good Environmental Status (GES) of marine waters by 2020. To achieve this, the MSFD introduced an obligation for their Member Received: May 30, 2018 Countries to develop marine strategies in several steps that
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© XXXX American Chemical Society
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DOI: 10.1021/acs.est.8b02906 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
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Environmental Science & Technology
Figure 1. Map of Spanish Administatrative Divisions and EU Marine Subregions.
over other analytical techniques such as atomic absorption spectroscopy (AAS) or voltammetry are, instead of its multielement capability, the lower detection limits, larger linear range, and better precision. However, in all cases its application to the direct analysis of seawater remains quite limited due to the low tolerance of the instruments to salt. Therefore, the pretreatment of samples using preconcentration techniques (e.g., chelation solvent extraction or solid phase extraction) to separate analytes from the sample matrix, and to obtain the desired detection limits, is an important prerequisite for seawater analysis. Since these procedures are not included in the analysis of the monitoring programs, the dilution of the samples is likely to be the only procedure applied for direct determination of trace elements, which increases considerably the detection limits. This precludes knowing the background levels of each water-mass and their environmental variations (Figure 1). Finally, the established maximum allowable concentration (MAC) and annual average concentration (AA) for each priority metal in surface waters that do not cause harm (i.e., Cd: 0.45 and 0.2 μg/L, Pb:7.2 and 7.2 μg/L; Hg: 0.07 and 0.05 μg/L, Ni: 20, and 20 μg/L, respectively) are too conservative and does not guarantee the GES. These limits were established by the European legislation to avoid serious irreversible consequences for eco-systems due to acute exposure in the short (MAC) and long (AA) term. However, the ecological effect of trace metals on the marine ecosystem varies for each marine regions of the EU since each one of them is affected by different dominant external and/or internal sources. Levels of metals in EU coasts can be affected by external sources such as river discharges, submarine groundwater discharges, atmospheric dust deposition, or anthropogenic sources among others. Sediment resuspension or diagenetic exchanges of trace elements across the water sediment are major internal
sources that can increase the background trace metal levels in a particular zone. All these processes affect the concentration of metals in the surrounding water masses in different ways, as they do their natural geochemical cycles, which will influence the global dynamics, the phytoplankton functioning, and the coastal biology in general. For example, Cd, Pb, and Ni concentration in waters vary significantly among different Mediterranean marine regions, which may lead to the development of adaptation processes and the natural selection of more or less resistant local biological populations. It has also been demonstrated that depending on cell sizes lethal levels of Cd and Pb are highly variable among marine phytoplankton communities. Phytoplankton toxicity responses show a significant variation depending on whether the experiments are carried out in the lab and or in the field.1 Thus, it has been reported that phytoplankton cell abundance and growth rates decrease from concentrations of Cd and Pb of 0.11 μg/L,1 which is much lower (1 order of magnitude lower in the case of Pb) than the established MAC and AA levels. Therefore, in order to maintain and guarantee a good environmental quality, limit concentrations should be established differently for each marine region according to their background levels and ecological characteristic. In spite of the well-recognized role that trace metals play in the functioning of the ocean (some of them as essential for the marine biota, such as Fe, Co, Zn, and others like Pb or Hg which are considered toxic when present in high concentrations) the existing data of trace metals concentrations in the marine environment remains very limited. Aware of this, the scientific community, in a joint effort, created the international research program Geotraces in 2003 (http://www.geotraces. org). With the active participation of scientists from 35 nations, Geotraces has significantly advanced the study of the global marine biogeochemical cycles of trace elements and B
DOI: 10.1021/acs.est.8b02906 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
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Environmental Science & Technology their isotopes. The program has increased considerably the metal data available around the world and protocols for sampling and analysis were developed early as a high priority to ensure data quality. Thus, the success of the monitoring programs depends on the collaboration of the administrative and scientific communities in order to ensure coherence in the actions, guarantee valid and useful results which in turn could help to understand the ecological status of the marine environment, to implement a real ecosystem approach, and in consequence to improve its management. Refs 2, 3, 4, 5.
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AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Notes
The authors declare no competing financial interest.
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REFERENCES
(1) Echeveste, P.; Agustí, S.; Tovar-Sánchez, A. Toxic Thresholds of Cadmium and Lead to Oceanic Phytoplankton: Cell Size and Ocean Basin-Dependent Effects. Environ. Toxicol. Chem. 2012, 31 (8), 1887−1894. (2) Santos-Echeandía, J.; Prego, R.; Cobelo-García, A. Intra-Annual Variation and Baseline Concentrations of Dissolved Trace Metals in the Vigo Ria and Adjacent Coastal Waters (NE Atlantic Coast). Mar. Pollut. Bull. 2009, 58 (2), 298−303. (3) Santos-Echeandía, J.; Caetano, M.; Brito, P.; Canario, J.; Vale, C. The Relevance of Defining Trace Metal Baselines in Coastal Waters at a Regional Scale: The Case of the Portuguese Coast (SW Europe). Mar. Environ. Res. 2012, 79, 86−99. (4) Pinedo-González, P.; West, A. J.; Tovar-Sánchez, A.; Duarte, C. M.; Marañoń , E.; Cermeño, P.; González, N.; Sobrino, C.; HueteOrtega, M.; Fernández, A.; et al. Surface Distribution of Dissolved Trace Metals in the Oligotrophic Ocean and Their Influence on Phytoplankton Biomass and Productivity. Glob. Biogeochem. Cycles 2015, 29 (10), 2015GB005149. (5) Tovar-Sánchez, A.; Basterretxea, G.; Rodellas, V.; SánchezQuiles, D.; García-Orellana, J.; Masqué, P.; Jordi, A.; López, J. M.; Garcia-Solsona, E. Contribution of Groundwater Discharge to the Coastal Dissolved Nutrients and Trace Metal Concentrations in Majorca Island: Karstic vs Detrital Systems. Environ. Sci. Technol. 2014, 48, 11819.
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DOI: 10.1021/acs.est.8b02906 Environ. Sci. Technol. XXXX, XXX, XXX−XXX
