C. Carlon

Risk based characterisation of contaminated industrial site using multivariate and geostatistical tools

Human and ecological risk assessment requires the sources, distribution, mobility and environmental behaviour of contaminants to be investigated on a site-specific basis. It often deals with data sets which are relatively small and affected by sampling gaps. In the case of a polycyclic aromatic hydrocarbon (PAH) contaminated industrial site, Kriging interpolation of spatial data and principal component analysis (PCA) proved useful for extracting additional value from the data set. Kriging was adopted for assessing the horizontal and vertical distribution and transport of PAHs in soil. PCA was applied to PAH concentration and relative abundance in soil samples and interpreted on the basis of the PAH physico-chemical and bio-degradation properties. It revealed correlation with the products of a neighbouring factory and the weathering of the lighter PAHs. The geo- and multivariate statistical results were coupled with the previous hydrogeological characterisation of the site to develop a site-conceptual model for use in the exposure scenario modelling for risk assessment.

Regression models to predict water-soil heavy metals partition coefficients in risk assessment studies

Risk assessment studies apply fate and transport models to predict the behaviour of chemicals in the environment. The definition of physico-chemical properties is crucial to predict the mobility of pollutants and heavy metals in particular within the environmental compartments. The conservative approach normally adopted at a screening level in attributing a value to the K(d) value, results in an extremely variable mobility in soil. In this paper a regression model to estimate rapidly the K(d) for heavy metals is proposed and applied to Pb, allowing a considerable reduction (3-4 orders of magnitude) of the estimation uncertainty. The application of a stepwise forward multiple regression to literature data provided a pH-dependent regression equation of the soil-water distribution coefficient (K(d)) for Pb: log K(d)=1.99+0.42 pH.

Characterization of contaminated soil and groundwater surrounding an illegal landfill (S.Giuliano, Venice, Italy) by principal component analysis and kriging

The characterization of a hydrologically complex contaminated site bordering the lagoon of Venice (Italy) was undertaken by investigating soils and groundwaters affected by the chemical contaminants originated by the wastes dumped into an illegal landfill. Statistical tools such as principal components analysis and geostatistical techniques were applied to obtain the spatial distribution of chemical contaminants. Dissolved organic carbon (DOC), SO4(2-) and Cl- were used to trace the migration of the contaminants from the top soil to the underlying groundwaters. The chemical and hydrogeological available information was assembled to obtain the schematic of the conceptual model of the contaminated site capable to support the formulation of major exposure scenarios, which are also provided.

The possibilities for the EU-wide use of similar ecological risk-based soil contamination assessment tools

Soil degradation, e.g. due to soil contamination, is a serious problem in Europe. Therefore, the European Commission believes that a comprehensive EU strategy for soil protection is required. With the purpose of supporting the European soil policy, the possibilities for a common approach in the EU-wide use of ecological risks assessment methodologies are explored. For over ten years now, ecological procedures used in different countries have been discussed in international fora. More recently, within the framework of the HERACLES network a review of ecological risk assessment tools was performed, among other things. From this study it can be concluded that the inclusion of ecological risk assessment in soil quality standards shows an increasing interest in many EU Member States. The study also shows that there are many procedures for ecological risk assessment readily available in several EU countries and will be readily available in even more Member States in the nearby future. Besides, this study clearly shows quite some variation in the ecological risk assessment tools and in the resulting soil quality standards in the different countries. Therefore, an effort was made to look for potential harmonisation of these tools within the European Union. Risk assessment tools used in soil quality assessment include both political and scientific elements, which are often interwoven. Insofar differences in the existing tools originate from geographical or cultural differences between Member States or from political choices, harmonisation is not at all regarded an option. Nevertheless, several differences between existing ecological risk assessment tools have been identified, that merely originate from scientific or technical aspects. These tools could be standardized, which means that there could be a uniform tool to be used everywhere throughout the EU. The development of these harmonised risk assessment tools will imply an intensive international cooperation, with the purpose of at least making the existing differences between those tools from the Member States transparent and to investigate the possibilities for coming to similar tools from a scientific/technical perspective.

Analytical and environmental chemistry in the framework of risk assessment and management: The lagoon of Venice as a case study

Prevention of toxic pollutant discharge and remediation of contaminated sediments and soils are topics increasingly addressed by the scientific community and the stakeholders. The research activity carried out on the lagoon of Venice highlights the crucial role played by analytical and environmental chemistry in assessing the environmental behavior of chemicals (i.e. occurrence level, transformation, ultimate fate) and exposure of human and environmental targets to pollutants. The extrapolation from analytical data to decisional steps was accomplished by data treatment (descriptive and multivariate statistics, spatial statistics), environmental modeling (e.g. partitioning bioaccumulation models and linear regression models), environ- mental risk assessment (ERA), and a GIS-based Decision Support System (DSS). Results obtained by this integrated approach supported analytical and environmental chemistry by improving the selection of priority pollutants, optimizing sampling design, and identifying critical environmental pathways. Both uncertainty minimization and cost saving of the overall decision process could be achieved. Selected results are presented here on the application of the proposed approach to the contaminated sediments of the lagoon of Venice and to the brownfield of the Porto Marghera industrial district. Both well-known persistent pollutants (e.g. polychlorinated dioxins/furans (PCDD/Fs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), metals and metalloids, and aromatic surfactants and their metabolites), as well as new classes of pollutants (e.g. endocrine disrupting compounds, EDCs) were investigated. The analytical data indicated that the most persistent and toxic organic and inorganic chemicals were found mainly in bottom sediments (especially those near the Porto Marghera industrial district), while substances such as surfactants and their metabolites and EDCs occurred mainly in water and were redistributed over the whole lagoon. Ex- posure characterization allowed Environmental Risk Assessment (ERA) to be undertaken, including the estimation of risk for both human and environmental health. The ERA procedure, developed according to a tiered approach, was applied to contaminated soils of the Porto Marghera industrial district. The ecological risk associated with contaminated lagoon sediments for the benthic community and aquatic food web was also assessed, resulting in a significant risk posed especially by mercury, cadmium and PAHs. Finally, a risk-based decision support system (DSS) for the rehabilitation of the Porto Marghera contaminated site was developed, which included environmental risk and remediation technologies.

Ecological risk assessment of persistent toxic substances for the clam Tapes philipinarum in the lagoon of venice, italy

Because of contamination of sediments of the Lagoon of Venice, Italy, by inorganic pollutants (e.g., arsenic, cadmium, chromium, copper, lead, mercury, nickel, and zinc) and organic pollutants (e.g., polychlorobiphenyls), as well as the ecological and economical relevance of the edible clam Tapes philipinarum, an ecological risk assessment was undertaken to ascertain the extent of bioaccumulation that would pose a significant risk. Risk was estimated by means of toxic units and hazard quotient approaches, by comparing the exposure concentration with the effect concentration. Clam exposure was estimated by applying previous results based on bioaccumulation spatial regression models. In addition, a comparison was made between sum of dioxin-like polychlorinated biphenyl (PCB) congeners and total PCB bioaccumulation provided by spatial regression models and by a partitioning model. The effect concentrations were calculated as tissue screening concentrations, as the product of pollutant sediment quality criteria and the bioaccumulation factor. Finally, the cumulative risk posed by selected inorganic pollutants and total PCBs was estimated and a map of risk was drawn. The resulting chemicals of potential ecological concern were mercury, cadmium, arsenic, and nickel, as well as, to a lesser extent, total PCBs.

Bayesian Statistics-Based Procedure for Sampling of Contaminated Sites

A variable density sampling pattern based on Bayesian statistics is presented and compared to a uniform density statistical pattern and a judgmental approach in a real case study. The Bayesian statistics, supported by a software tool, supplied a soil sampling plan similar to the judgmental one, especially for the number of sampling points and their location. It allowed statistical goals to be set and expert judgment to be included in the sampling strategy in a transparent and systematic procedure. For these reasons, it appears quite suitable for inclusion into Quality Assurance Quality Control plans.

Applicability of the fish embryo acute toxicity (FET) test (OECD 236) in the regulatory context of Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH)

In 2013 the Organisation for Economic Co-operation and Development (OECD) test guideline (236) for fish embryo acute toxicity (FET) was adopted. It determines the acute toxicity of chemicals to embryonic fish. Previous studies show a good correlation of FET with the standard acute fish toxicity (AFT) test; however, the potential of the FET test to predict AFT, which is required by the Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) regulation (EC 1907/2006) and the Classification, Labelling and Packaging (CLP) Regulation (EC 1272/2008), has not yet been fully clarified. In 2015 the European Chemicals Agency (ECHA) requested that a consultant perform a scientific analysis of the applicability of FET to predict AFT. The purpose was to compare the toxicity of substances to fish embryos and to adult fish, and to investigate whether certain factors (e.g., physicochemical properties, modes of action, or chemical structures) could be used to define the applicability boundaries of the FET test. Given the limited data availability, the analysis focused on organic substances. The present critical review summarizes the main findings and discusses regulatory application of the FET test under REACH. Given some limitations (e.g., neurotoxic mode of action) and/or remaining uncertainties (e.g., deviation of some narcotic substances), it has been found that the FET test alone is currently not sufficient to meet the essential information on AFT as required by the REACH regulation. However, the test may be used within weight-of-evidence approaches together with other independent, relevant, and reliable sources of information. The present review also discusses further research needs that may overcome the remaining uncertainties and help to increase acceptance of FET as a replacement for AFT in the future. For example, an increase in the availability of data generated according to OECD test guideline 236 may provide evidence of a higher predictive power of the test. Environ Toxicol Chem 2018;37:657-670.

A system for the evaluation of environmental risk for lagoon arachaeological sites

The project Archeorisk is presented. The objective is to develop a Decision Support System (DSS) for the safeguard and the management of the underwater archaeological patrimony in the Lagoon of Venice. The DSS has been completed in the form of a software prototype working as an extension of a geographic informative system. The DSS allows to evaluate the entity, the type and the distribution of the decay risk to which the lagoon archaeological sites are subjected. Its development has requested the acquisition of experimental data on the decay of the findings and about the main causes. In particular, the decay of ceramic and wooden objects has been studied. The system, that can be adapted to different environmental and archaeological contexts, is destined to the Archaeological Superintendence and permits to integrate the safeguard of the cultural heritage with that of the natural environment.