Assessment and management of contaminated sediments in Italian ...

Assessment and management of contaminated sediments in Italian marine coastal waters Mario Carere(a), Luciano Depropris(b), Enzo Funari(a), Loredana Musmeci(a) and Fulvio Onorati(b) Dipartimento di Ambiente e Connessa Prevenzione Primaria, Istituto Superiore di Sanità, Rome, Italy Istituto Centrale per la Ricerca Scientifica e Tecnologica Applicata al Mare (ICRAM), Rome, Italy

(a) (b)

Summary. The Water Framework Directive (WFD) obliges Member State to achieve a good chemical and ecological status of all surface waterbodies within a specific deadline; in particular the good chemical status is a condition in which the concentrations of priority substances do not exceed the environmental quality standards (EQS) in order to protect human health and the environment; the WFD states that EQS have to be derived for water, sediment or biota. The good chemical status could be difficult to achieve in the historical marine contaminated water bodies due to the presence of high concentrations of toxic, bioaccumulative and persistent substances in the sediments. In these specific highly contaminated sites there is a need to apply an ecosystem approach in which, as a first step, less stringent sediment EQS are defined in order to take the appropriate measures for the protection of aquatic ecosystems and human health; the long-term goal for these sites is the achievement of the good chemical status foreseen by the WFD. The methodology applied in Italy for the sediment quality assessment of marine contaminated sites is explained in this paper. Key words: ecosistemi acquatici, standard di qualità ambientale, siti contaminati, Direttiva Quadro Acque, sedimenti.

Riassunto (Valutazione e gestione dei sedimenti contaminati nelle acque marino costiere in Italia). La Direttiva Quadro Acque obbliga gli Stati Membri a raggiungere lo stato chimico ed ecologico buono di tutti i corpi idrici superficiali entro una specifica scadenza temporale; in particolare lo stato chimico buono è una condizione in cui le concentrazioni delle sostanze prioritarie non superano gli standard di qualità ambientali (SQA) al fine di proteggere la salute umana e l’ambiente; la Direttiva Quadro Acque prevede che gli SQA possono essere derivati per acqua, sedimenti e biota. Lo stato chimico buono può essere difficile da raggiungere nei corpi idrici marini fortemente contaminati a causa della presenza di elevate concentrazioni di sostanze persistenti, bioaccumulabili e tossiche nei sedimenti. In questi specifici siti altamente contaminati vi è una necessità di applicare un approccio ecosistemico nel quale, come prima fase, vengono definiti SQA dei sedimenti meno stringenti allo scopo di applicare le misure più appropriate per la protezione degli ecosistemi acquatici e della salute umana; l’obiettivo a lungo termine per questi siti è il raggiungimento del buono stato previsto dalla Direttiva Quadro sulle Acque. La metodologia applicata in Italia per la valutazione della qualità dei sedimenti nei siti marini contaminati viene descritta in questo articolo. Parole chiave: aquatic ecosystems, environmental quality standard, contaminated sites, water framework directive, sediment.

Introduction One of the aims of the Water Framework Directive is the achievement of a good surface water chemical status within 2015 [1]. In the context of the WFD Common Implementation Strategy (CIS) the immediate focus has been to derive environmental quality standards (EQS) for the water phase, however it is recognised in the CIS that monitoring programmes for lipophilic priority substances should also be focused on sediment and biota. The Scientific Committe on Toxicology, Ecotoxicology and the Environment (CSTEE) in the opinion on the setting of EQS of priority substances for the water

environment as a general conclusion believes that specific quality standard can and should be developed for sediment and biota [2]. The new Directive proposal [3] that set EQS for 41 dangerous substances (the 33 priority substances and 8 other pollutants), after the political agreement of 21 June 2007 provides that Member States can derive EQS for sediment instead of water for specified substances; the EQS for sediment have to guarantee the same level of protection of the EQS derived for water. Member States have to notify, through the Committee referred to in Article 21 of Directive 2000/60/EC, the substances for which EQS have been established, the

Address for correspondence: Mario Carere, Dipartimento di Ambiente e Connessa Prevenzione Primaria, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy. E-mail: [email protected].

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Table 1 | Criteria for the derivation of sediment quality standard and intervention values Criteria

Technical principle

Objectives of protection

Ecotoxicological

Aquatic life - Benthic community

Human health Monitoring data

Threshold effect level Probable effect level Maximum tissue residue level – TDI principle Critical areas – Pristine areas

Background levels

Geochemistry of the sediment

reasons and basis for using this approach, the alternative EQS established, including the data and the methodology by which they were derived and the categories of surface water to which they would apply. There is the awareness at European level, both at scientific and policy level, of the need to assess sediment quality also through the derivation of EQS for this matrix. The derivation of EQS for sediment seems more appropriate for specific water bodies like marine coastal and transitional waters in which sediment represents the final sink of many pollutants and at the same time the place in which most of the aquatic organisms live or have part of the life-cycle; in these waterbodies monitoring programmes in water column for some lipophilic compounds may be very misleading with regard to the real state of the environmental and chemical quality. Is it recognised from the International Scientific Community that the assessment of sediment quality should not be based only on chemical analysis, but should include also the use of bioassays for the effect assessment and the evaluation of ecological quality for the impact assessment; usually the use of EQS is a simple and applicable tool for the environmental manager because it can be used for different purposes: - as a basis for establishing site-management goals and in some cases long term remediation targets; - for the determination of environmental quality objective; - for determining if site remediation is necessary (following detailed site investigations); - for determining the factors and the sources that are most likely associated with sediment contamination; - as a criteria for the opening of shellfish (for instance clams) culture areas; - for the protection of habitats used by endangered or threatened species or species of special concern; - for the support of design of sampling programs (during site investigations). In Italy with the Italian Ministerial Decree 367/03 EQS for 27 pollutants have been derived in the sediment of marine coastal area, lagoons and coastal ponds [4]. Most of the pollutants selected are the priority and priority hazardous substances of the Water Framework Directive. The derivation of the EQS (Table 1) has been based on the direct risks for the benthic communities, but also on the risks

Human health (consumption of seafood)

for human health through consumption of seafood. The Italian Sediment EQS are criteria for the definition of the good status of marine coastal, lagoons and coastal ponds; they don’t represent a pass/fail value in the context of the actual legislative Italian framework, but a support tool to evaluate the degree of contamination and to take the appropriate measures to tackle the pollution of waterbodies. The WFD states that Member States (MS) may aim to achieve less stringent environmental objectives for specific water bodies when they are so affected by human activity that the achievement of these objectives would be infeasible or too much expensive. In this case MS have to ensure for surface water 1) the highest ecological and chemical status possible is achieved, given impacts that could not reasonably have been avoided due to the nature of human activity or pollution 2) that no further deterioration occurs in the status of the affected body of water; the establishment of less stringent environmental objectives have to be specifically mentioned in the river basin management plans that have to be elaborated within 2009 in compliance with the WFD deadlines. In Italy a national programme for the remediation of contaminated sites [5] has been put in place, more than 50 areas have been defined remediation sites of national interest; some of these sites are marine coastal waters characterized by past anthropogenic pressures and in proximity of these sites different uses (aquaculture, bathing, fishing, etc.) are in place. Most of these sites are characterized by high sediment contamination due in particular to persistent, bioaccumulative and toxic (PBT) substances like for example mercury, cadmium, PAH, PCB, hexachlorobenzene; the half-time of the substances is long and the environmental quality objectives are far to achieve also if all the possible sources of pollution will be stopped. For the mentioned reasons intervention values for sediment of a list of dangerous substances have been derived for some of these highly marine contaminated sites. These values represent an operative and pragmatic tool that allows the identification of areas where remediation actions need to be activated as soon as possible; at the same time they represent a short-term objective to achieve, in the context of the WFD, for historical contaminated sites. The intervention values have to take into account also the high geochemical heterogeneity of coastal

contaminated sediments in Italian marine coastal waters

sediments. In these highly contaminated sites the sediment EQS derived with the Italian Ministerial Decree 367/03 represent a long-term objective that has to be achieved following the adoption of all appropriate measures and taking into account the half-life of the specific substances detected. Material and Methods The approach for the derivation of site specific intervention values for the sediment matrix has been developed for heavy metals and organic pollutants. The approach selected for the derivation of intervention values has been the development of site specific probable effect level (PEL). The PEL is the geometric mean of the 50 percentiles of toxic samples and the 85 percentiles of non-toxic samples and represents the level above which adverse effects on benthic organisms are frequently expected. PEL for heavy metals, organometals, PAH, organochlorine pesticides, PCB and “dioxins” have been derived in 6 Italian marine contaminated sites; some of these compounds (Table 2) are the priority substances of the Water Framework Directive. The compounds selected are the same of those included in the Italian Ministerial Decree 367/03 also with the aim to harmonize the different monitoring programmes foreseen for the achievement of environmental quality objective and the remediation of contaminated sites. Site specific PEL have been derived for heavy metals through the use of chemical analysis and a battery of available bioassays of different trophic levels with defined endpoints, the bioassays have been performed on endemic species of the areas subject of the study; for the organic pollutants international PEL have been selected [6]. For this reason the inter-

Table 2 | substances selected for the derivation of intervention value and their classification in EU legislation Substances

EU-Water Framework Directive classification

Cadmium Mercury Lead Nickel Tributyltin Benzo(a)pyrene Anthracene Fluoranthene Naftalene Hexachlorocyclohexane Hexachlorobenzene Aldrin

Priority hazardous Priority hazardous Priority Priority Priority hazardous Priority hazardous Priority hazardous Priority Priority Priority hazardous Priority hazardous List I Directive 76/464/CE (elimination of pollution) List I Directive 76/464/CE (elimination of pollution) List I Directive 76/464/CE (elimination of pollution)

Dieldrin DDT, DDD, DDE

vention values derived for the organic contaminants are the same for each area because the international criteria has been applied while the values for heavy metals are different. The approach used is the same that has been applied for the derivation of the Italian sediment quality standard of the Italian Ministerial Decree 367/03, in this case the criteria selected for the protection of the benthic community were the effect level approach of Long and Mac Donald, in particular the threshold effect level (TEL). The TEL is calculated as the geometric mean of the 15th percentile concentration of the toxic effects data set and the median of the no-effects data set; as such it represents the concentration below which adverse effects are expected to occur only rarely. For some compounds have been calculated site-specific TEL taking into account the local benthic community; for most of the compounds the TEL derived by Long and Mc Donald have been incorporated. The compounds selected are heavy metals, organometals, PAH, chlorinated pesticides, PCB, PCDD and PCDF. Local background levels have to be evaluated for the heavy metals compliance. For bioaccumulative compounds has been taking into account the risk of contaminated sediment for human health through the consumption of seafood. For dioxin and PCB dioxin-like a provisional human health sediment quality criteria (HHSQC) has been derived through the calculation of the following elements: - the European tolerable daily intake (TDI) of dioxin and dioxin-like PCB; - the total dioxin Italian exposure; - the contribution of fish products; - the average concentration of PCDD-PCDF in fish products in Italy; - the maximum residue limits in shellfish; - correlation between sediment and benthic edible biota chemical concentration. Discussion The WFD obliges MS to achieve a good chemical status also for heavily modified and artificial waterbodies like for example harbour areas; at the same time there are possibilities to use derogations and MS can have the possibility to achieve less stringent objective for specific waterbodies affected by massive pollution. Different approaches for the derivation of sediment quality criteria have been applied widely in Europe, USA, Canada and Australia. The European Commission does not oblige MS to follow a particular methodology however it suggests two alternative procedures for the derivation of sediment EQS. In the context of the CIS of the WFD the Expert Advisory Forum on Priority Substances (EAF PS) suggests that QS for sediment should preferably be derived on the basis of toxicity tests with sediment dwelling organisms and application of the safety fac-

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Table 3 | Possible management measures compared to different degrees of contamination Light contamination

Moderate contamination

Strong contamination

Additional investigation and monitoring

Disposal in CDF or coastal confined structures

Disposal in an upland waste site

Possible prohibition of fishing, bathing

Dredging and (ex situ) treatment for later reuse in civil works, according to the existing legislation

(Ex situ) treatment for later disposal in CDF or coastal confined structures

Prohibition of shellfish harvesting

tors in relation to the quality and quantity of data; this is in line with the Technical Guidance Document on Risk Assessment [7] in which is described the procedure to derive the PNEC (predicted no effect concentration) for freshwater and marine sediment; in the procedure assessment factors have to be applied in relation to the quality and quantity of ecotoxicological data. The objective of this methodology is the protection of benthic organisms from the direct toxic effects of contaminated sediment, however it doesn’t take into account the possible toxic effects to human health due to bioaccumulation in the food web. The second procedure suggested by the EU is the so called equilibrium partitioning method that may be used in order to extrapolate a quality standard applicable to the concentration in sediment starting with the EQS derived for column water. During the process of the development of the Italian sediment standards, both environmental objective and intervention value, it has been clear that the use of partition coefficients obtained for a generic sediment with properties that can be very different from those of the real sediment, can over or under estimate the associated effects for the benthic organisms. The TEL/PEL approach has been selected because is one of the most widely used criteria for the assessment and management of contaminated sediments in Europe, USA and Canada; furthermore this criteria has the advantage to take into account chemical analysis and bioassays and can be used to achieve different objectives. Most of the substances selected are included in the priority list [8, 9] of the European Union, these substances have to be reduced (priority) or eliminated (priority hazardous) from all discharges, emissions, releases and loss within 20 years from the adoption of measures at European level. In order to take the appropriate management measures the use of the PEL has been integrated with data from ecotoxicological assays and bioaccumulation tests. For the metals also the use of background levels has been taking into account. The numerical values derived, integrated with data from ecotoxicological assays and bioaccumulation tests, will allow to select areas where remediation actions is needed. The intervention procedure and the put in place of possible management measures (Table 3) will be activated taking also into account the following criteria:

- how many parameters are above the intervention values; - which parameter is above the intervention values; - the number of the samples with values higher than the intervention values; - the level of exceeding of the intervention values; - volumes and spatial distribution of sediments with concentrations higher than the intervention values; - different uses of the area. Certain pollutants can bioaccumulate in the food web, in particular in fish and shellfish; as a result there is concern that contaminated sediment pose a health threat to humans through the consumption of seafood. The procedures to derive human health sediment quality standards are not common and are usually based on the tolerable daily intake (TDI) principle; in USA [10] has been also developed a methodology to derive a linkage between chemical residue levels in specific organisms and chemical concentrations in sediments through the use of BSAF (biota sediment accumulation factor) or the use of statistical analysis. The TDI methodology is difficult to apply due to the lackness of information on the diet of the people who live in proximity of the areas subject of the study and also because the correlation between sediment and biota concentration is not always linear; in the case of ministerial decree 367/03 has been possible to derive a provisional value for dioxins and PCB dioxin-like taking into account several investigations that were carried out by the Istituto Superiore di Sanità (ISS, the Italian National Institute of Health) during the 90’s in the Venice lagoon [11]. Conclusions An approach for the assessment and management of contaminated marine sediment has been developed in Italy; most of the dangerous substances are the priority and priority hazardous substances selected at European level. The methodology takes into account two different objectives: a) the shortterm objective that has the aim to decide when the intervention is needed and the type of measure that has to be adopted considering the uses of the area and the level of contamination b) the long-term objective that is analogous to the sediment quality standard included in the Italian Ministerial Decree. The numerical criteria-based approach can provide the basis for setting priorities and determining when sediment remediation is needed; this approach is in

contaminated sediments in Italian marine coastal waters

line with the requirements of the Water Framework Directive for which the “probable effect level” could represent a short-term objective for specific water bodies affected by historical contamination. The chemical criteria approach should be supported by bioassays, bioaccumulation tests and ecological analysis with the aim to define an integrated assessment of contaminated sediments and to evalu-

ate better the toxic effects on the benthic organisms and the impacts on the aquatic ecosystems; the assessment framework should have a broad consensus, be flexible and ready to be adapted when new data become available. Submitted on invitation. Accepted on 3 June 2008.

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derived sediment quality guidelines for marine and estuarine ecosystems. Hum Ecol Risk Assess 1998;4(5):1019-39. 7. European Commission. Technical Guidance Document in support of Commission Directive 93/67/EEC on Risk Assessment for new notified substances, Commission Regulation (EC) No 1488/94 on Risk Assessment for existing substances and Directive 98/8/EC of the European Parliament and of the Council concerning the placing of biocidal products on the market. EUR 20418 EN/1. Available from: http://ecb.jrc.it/documentation; last visited 25/05/08. 8. European Union. Decision No 2455/2001/EC of the European Parliament and of the Council of 20 November 2001 establishing the list of priority substances in the field of water policy and amending Directive 2000/60/CE. Official Journal L 351, 15 December 2001. 9. European Union. Directive 76/464/EEC of 4 May 1976 on pollution caused by certain dangerous substances discharged into the aquatic environment of the Community. Official Journal L 129, 18 May 1976. 10. Washington State department of Ecology. Developing healthbased sediment quality criteria for cleanup sites: a case study report. 1997. Available from: www.ecy.wa.gov/biblio/97114.htlm; last visited 10/03/08. 11. Di Domenico A, Miniero R. Transfer of PCDDs and PCDFs from bottom sediments to clams (Tapes sp.) in the Venice lagoon: a preliminary assessment. Organohal Comp 2000;49:473-6.

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