Regional risk assessment for contaminated sites part 2: ranking of potentially contaminated sites

Environmental risks are traditionally assessed and presented in non spatial ways although the heterogeneity of the contaminants spatial distributions, the spatial positions and relations between receptors and stressors, as well as the spatial distribution of the variables involved in the risk assessment, strongly influence exposure estimations and hence risks. Taking into account spatial variability is increasingly being recognized as a further and essential step in sound exposure and risk assessment. To address this issue an innovative methodology which integrates spatial analysis and a relative risk approach was developed. The purpose of this methodology is to prioritize sites at regional scale where a preliminary site investigation may be required. The methodology aimed at supporting the inventory of contaminated sites was implemented within the spatial decision support sYstem for Regional rIsk Assessment of DEgraded land, SYRIADE, and was applied to the case-study of the Upper Silesia region (Poland). The developed methodology and tool are both flexible and easy to adapt to different regional contexts, allowing the user to introduce the regional relevant parameters identified on the basis of user expertise and regional data availability. Moreover, the used GIS functionalities, integrated with mathematical approaches, allow to take into consideration, all at once, the multiplicity of sources and impacted receptors within the region of concern, to assess the risks posed by all contaminated sites in the region and, finally, to provide a risk-based ranking of the potentially contaminated sites.     

Regional risk assessment for contaminated sites part 1: vulnerability assessment by multicriteria decision analysis

As highlighted in the EU Soil Communication, local contamination is one of the main soil threats and it is often related to present and past industrial activities which left a legacy of a high number of contaminated sites in Europe. These contaminated sites can be harmful to many different receptors according to their sensitivity/susceptibility to contamination, and specific vulnerability evaluations are needed in order to manage this widely spread environmental issue. In this paper a novel comprehensive vulnerability assessment framework to assess regional receptor susceptibility to contaminated site is presented. The developed methodology, which combines multi criteria decision analysis (MCDA) techniques and spatial analysis, can be applied to different receptors recognized as relevant for regional assessment. In order to characterize each receptor, picked parameters significant for the estimation of the vulnerability to contaminated sites have been selected, normalized and aggregated by means of multi criteria decision analysis (MCDA) techniques. The developed MCDA methodology, based on the Choquet integral, allows to include expert judgments for the elicitation of synergic and conflicting effects between involved criteria and is applied to all the geographical objects representing the identified receptors. To test the potential of the vulnerability methodology, it has been applied to a specific case study area in the upper Silesia region of Poland where it proved to be reliable and consistent with the environmental experts' expected results. The vulnerability assessment results indicate that groundwater is the most vulnerable receptor characterized by a wide area with vulnerability scores belonging to the highest vulnerability class. As far as the other receptors are concerned, human health and surface water are characterized by quite homogeneous vulnerability scores falling in the medium-high vulnerability classes, while protected areas resulted to be the less vulnerable receptor with only one protected area falling in the medium vulnerability class. The vulnerability assessment results will support the regional risk assessment for the ranking of potentially contaminated sites at regional scale.     

Regional risk assessment for contaminated sites Part 3: Spatial decision support system

Large scale (e.g. regional or national) assessments of contaminated sites may be very costly in terms of investigation and methodological (i.e. risk assessment procedures) requirements and may produce a quantity of information that usually discourages examination by decision-makers. Moreover, most of the existing tools effectively support local environmental risk assessment and management, but lack the capabilities of larger scale analysis, not mentioning the absence of the relevant component of socio-economic prioritization. To respond to the concerns and the management needs of experts and decision makers, the Spatial decision support sYstem for Regional rIsk Assessment of Degraded land (SYRIADE DSS) was developed and is presented according to its three modules: Regional Risk Assessment, Socio-economic Assessment and Integrated Assessment, respectively. The system allows to rank potentially contaminated sites for priority of investigation, when no information on characterization and risk by site specific methodologies is available. This GIS-based system embeds an innovative spatial and relative risk assessment procedure, and proposes the integrated analysis of different data (environmental and socio-economic) for the concerned sites, eliciting when necessary experts' knowledge and stakeholders' values (through Multi Criteria Decision Analysis, MCDA, methodologies). The application to a Polish case-study shows the performance and the flexibility of the system in investigating and mapping (potentially) contaminated sites at the regional scale.     

Regional multi-compartment ecological risk assessment: Establishing cadmium pollution risk in the northern Bohai Rim,China

Ecological risk assessment (ERA) has been widely applied in characterizing the risk of chemicals to organisms and ecosystems. The paucity of toxicity data on local biota living in the different compartments of an ecosystem and the absence of a suitable methodology for multi-compartment spatial risk assessment at the regional scale has held back this field. The major objective of this study was to develop a methodology to quantify and distinguish the spatial distribution of risk to ecosystems at a regional scale. A framework for regional multi-compartment probabilistic ecological risk assessment (RMPERA) was constructed and corroborated using a bioassay of a local species. The risks from cadmium (Cd) pollution in river water, river sediment, coastal water, coastal surface sediment and soil in northern Bohai Rim were examined. The results indicated that the local organisms in soil, river, coastal water, and coastal sediment were affected by Cd. The greatest impacts from Cd were identified in the Tianjin and Huludao areas. The overall multi-compartment risk was 31.4% in the region. The methodology provides a new approach for regional multi-compartment ecological risk assessment.     

Evaluation and ranking of restoration strategies for radioactively contaminated sites.

An international project, whose aim was the development of a transparent and robust method for evaluating and ranking restoration strategies for radioactively contaminated sites (RESTRAT), was carried out under the Fourth Framework of the Nuclear Fission Safety Programme of the EU. The evaluation and ranking procedure used was based on the principles of justification and optimisation for radiation protection. A multi-attribute utility analysis was applied to allow for the inclusion of radiological health effects, economic costs and social factors. Values of these attributes were converted into utility values by applying linear utility functions and weighting factors, derived from scaling constants and expert judgement. The uncertainties and variabilities associated with these utility functions and weighting factors were dealt with by a probabilistic approach which utilised a Latin Hypercube Sampling technique. Potentially relevant restoration techniques were identified and their characteristics determined through a literature review. The methodology developed by this project has been illustrated by application to representative examples of different categories of contaminated sites; a waste disposal site, a uranium tailing site and a contaminated freshwater river.     

A spatial risk assessment methodology to support the remediation of contaminated land

When soil and groundwater contaminations occur over large areas, remediation measures should be spatially prioritized on the basis of the risk posed to human health and in compliance with technological and budget constraints. Within this scope, the application of human health risk assessment algorithms in a spatially resolved environment raises a number of methodological and technical complexities. In this paper, a methodology is proposed and applied in a case study to support the entire formulation process of remediation plans, encompassing hazard assessment, exposure assessment, risk characterisation, uncertainty assessment and allocation of risk reduction measures. In the hazard assessment, it supports the selection of Contaminants of Concern (CoC) with regard to both their average concentrations and peak concentrations, i.e. hot spots. In the exposure assessment, it provides a zoning of the site based on the geostatistical mapping of contaminant. In the risk characterisation, it generates vector maps of Risk Factors on the basis of the risk posed by multiple substances and allows the interrogation of most relevant CoC and exposure pathways for each zone of the site. It also supports the Monte Carlo based probabilistic estimation of the Risk Factors and generates maps of the associated uncertainty. In the risk reduction phase, it supports the formulation of remediation plans based on the stepwise spatial allocation of remediation interventions and the on-time simulation of risk reduction performances. The application of this methodology is fully supported by an easy-to-use and customized Geographical Information System and does not require high expertise for interpretation. The proposed methodology is the core module of a Decision Support System (DSS) that was implemented in the DESYRE software aimed at supporting the risk-based remediation of megasites.     

A review of regulatory decisions for environmental protection: part II - the case-study of contaminated land management in Portugal

This paper provides a case-study analysis of the challenges in the implementation of national soil policies, which was developed by the authors in Part I of the review of regulatory decisions for environmental protection [Rodrigues SM, Pereira ME, Ferreira da Silva E, Hursthouse A, Duarte AC. A review of regulatory decisions for environmental management: Part I-challenges in the implementation of national soil policies. Environ Int 2009. doi:10.1016/j.envint.2008.08.007]. The Portuguese case was selected as a case-study since specific regulatory decisions for contaminated land management are still in the early stages of development. Given the gap between the situation at the EU level and the state of Portuguese soil policy development, it is of merit to consider national contaminated land policy regimes already in place within the EU and to see if these provide a suitable basis to define the main challenges and research needs for the implementation of a Portuguese contaminated land management strategy. A framework combining the D-P-S-I-R (drivers-pressures-sources-impacts-responses) structure of policy evaluation with the Source-Pathway-Receptor approach to health risk assessment is proposed to derive an effective regulatory framework for managing contaminated land in Portugal, using available information and only to develop new data and research where knowledge gaps exist. Funding site clean-up and assigning liability were identified as relevant factors currently hampering site remediation. Most relevant research needs for the development of contaminated land management practices in Portugal are those associated to the definition of a risk assessment framework and setting guidelines for the evaluation of risks posed to both humans and ecosystems. Other relevant and innovative features are the integration of soil function analysis into site investigations and the definition of a framework that combines risk assessment with soil function analysis. The analysis of the Portuguese case also provides insight into the discussions needed for the effective development of regulatory decisions for contaminated land management in countries with no history of implementing specific soil policies.     

Which compounds contribute most to elevated airborne exposure and corresponding health risks in the Western Balkans?

A majority of ongoing monitoring of persistent organic pollutants (POPs) is currently focused on chemicals emphasized in the Stockholm Convention. Quantitative detection of other substances (especially those with numerous anthropogenic sources such as polyaromatic hydrocarbons (PAHs)) is, however, also needed since their concentrations are usually several orders of magnitude higher. A goal of this study was to determine how various groups of compounds contribute to total human health risks at the variety of sampling sites in the region of Western Balkan. Distribution of the risks between the gas and particulate phases was also addressed. Results showed that inhalation exposure to organochlorine pesticides (OCPs) does not represent a significant risk to humans, while polychlorinated biphenyls (PCBs) re-volatilized to the atmosphere from contaminated soils and buildings can pose a problem. PCB evaporation from primary sources (currently used PCB-filled transformers or non-adequate storage facilities) generally resulted in much higher atmospheric concentrations than evaporation from the secondary sources (soils at the sites of war destructions). A majority of the human health risks at the urban sites were associated with PAHs. Between 83 and 94% of the cumulative risk at such sites was assigned to chemicals sorbed to particles, and out of it, PAHs were responsible for 99%.     

Beyond contaminated land assessment: On costs and benefits of bioaccessibility prediction

Advances towards sustainable land management necessitate application of a broader portfolio of decision-support tools that improve evaluation of contaminated land. Over the last decade regulators have directed concerted effort towards rationalization of risk-based contaminated land policies recognizing bioavailability and bioaccessibility as concepts to be incorporated into risk assessments. The desire for a precise and rapid method to inform consideration of bioavailability and bioaccessibility to support risk assessment of contaminated land has never been greater. This study presents a comprehensive appraisal of both emerging non-exhaustive extraction techniques (subcritical water extraction and Brij 700 extraction) developed to reflect polycyclic aromatic hydrocarbon (PAH) bioaccessibility to microorganisms as well as formerly demonstrated methodologies (the use of cyclodextrins and butanol extraction). Application of unified evaluation criteria across different techniques enabled comparison not only from the bioaccessibility prediction perspective but also analysis of economical (cost of extraction) and practical (such as extraction time) measures. Whilst the use of cyclodextrins was the best predictor of the bioaccessible fraction for the majority of compounds, other methods appeared more cost- and time-effective. Juxtaposition of the techniques presented in this study assists establishing cost-benefit trade-offs of different non-exhaustive extraction techniques and contributes to tailoring information on contaminant bioaccessibility to support risk evaluation on contaminated sites.     

Risk assessment at hazardous waste-contaminated sites with variability of population characteristics

Risk assessment is considered to be an effective scientific tool which enables decisionmakers to manage hazardous waste-contaminated sites in a cost-effective manner while preserving public health. However, the current risk assessment framework proposed by the US Environmental Protection Agency (US EPA) has limitations in addressing the true variability of population characteristics. This study proposed a methodology that is different from the existing framework by accounting for the true variability of population characteristics. The key differences of the proposed methodology and the existing framework are the (1) use of the transient exposure concentration; (2) use of the entire population rather than a representative ideal individual; (3) use of age- and gender-based population subgroups to represent population characteristics; (4) use of a population growth model to represent growth dynamics; and (5) presentation of risk through a risk profile with risk summarized through a single indicator, potential cancer incidences (PCI). The proposed methodology was applied in a ground water contamination scenario due to benzene to determine its applicability. The results of the study showed that age-based variability of population characteristics is important in predicting the population risk while gender played a small role. The existing US EPA methodology and its variation using age-independent variability of population characteristics overestimate the risk given by PCI substantially, and therefore, the decisions can lead to costly cleanup goals. Population risk is not a single value but a distribution due to the contribution from ditferent individuals of the exposed population. Hence, the decision criterion proposed in this study, PCI, is found to be a useful indicator to describe population carcinogenic risk to the society under a variety of conditions and scenarios.     

Allozyme polymorphisms and heavy metal levels in the green-lipped mussel Perna viridis (Linnaeus) collected from contaminated and uncontaminated sites in Malaysia

It has been widely reported that heavy metal contamination in coastal waters can modify the allozyme profiles of marine organisms. Previous studies have recorded elevated metal concentrations in sediments and mussel tissues off Peninsular Malaysia. In the present study, horizontal starch gel electrophoresis was carried out to estimate the levels of allelic variation of the green-lipped mussel, Perna viridis, collected from one contaminated and three relatively uncontaminated sites off Peninsular Malaysia. Fourteen polymorphic loci were observed. In addition, the concentrations of cadmium, copper, lead, mercury and zinc were determined in the sediments and in the soft tissues of the mussels. Mussels from contaminated site, evidenced by high metal pollution indices (MPI) of the sediment and the mussel tissues, showed the highest percentage of polymorphic loci (78.6%), while those collected from the uncontaminated sites had lower MPI of the sediment and mussel tissue, and exhibited lower percentages of polymorphic loci (35.7-57.1%). The population from the contaminated site showed the highest excess of heterozygosity (0.289) when compared to that of the populations from the three uncontaminated sites (0.108-0.149). Allozyme frequencies at the phosphoglucomutase (PGM; E.C. 2.7.5.1) locus also differed between the contaminated and uncontaminated populations. Previous studies have shown that exposure to heavy metals can select or counter-select for particular alleles at this locus. The present results suggest that allozyme polymorphism in P. viridis is a potential biomonitoring tool for heavy metal contamination but further validation is required.     

Natural releases from contaminated groundwater, Example Reference Biosphere 2B

Safety assessment is a tool which, by means of an iterative procedure, allows the evaluation of the performance of a disposal system and its potential impact on human health and the environment. Radionuclides from a deep geological disposal facility may not reach the surface environment until many tens of thousands of years after closure of the facility. The BIOMASS Programme on BIOsphere Modelling and ASSessment developed Examples of "Reference Biospheres" to illustrate the use of the methodology and to demonstrate how biosphere models can be developed and justified as being fit for purpose. The practical examples are also intended to be useful in their own right. The Example Reference Biosphere 2B presented here involves the consideration of alternative types of geosphere-biosphere interfaces and calculation of doses to members of hypothetical exposure groups arising from a wide range of exposure pathways within agricultural and semi-natural environments, but without allowing for evolution of the corresponding biosphere system. The example presented can be used as a generic analysis in some situations although it was developed around a relatively specific conceptual model. It should be a useful practical example, but the above numerical results are not intended to be understood as prescribed biosphere 'conversion factors'.     

Analysis of currently available data for characterising the risk of engineered nanomaterials to the environment and human health--lessons learned from four case studies

Production volumes and the use of engineered nanomaterials in many innovative products are continuously increasing, however little is known about their potential risk for the environment and human health. We have reviewed publicly available hazard and exposure data for both, the environment and human health and attempted to carry out a basic risk assessment appraisal for four types of nanomaterials: fullerenes, carbon nanotubes, metals, and metal oxides (ENRHES project 2009(1)). This paper presents a summary of the results of the basic environmental and human health risk assessments of these case studies, highlighting the cross cutting issues and conclusions about fate and behaviour, exposure, hazard and methodological considerations. The risk assessment methodology being the basis for our case studies was that of a regulatory risk assessment under REACH (ECHA, 2008(2)), with modifications to adapt to the limited available data. If possible, environmental no-effect concentrations and human no-effect levels were established from relevant studies by applying assessment factors in line with the REACH guidance and compared to available exposure data to discuss possible risks. When the data did not allow a quantitative assessment, the risk was assessed qualitatively, e.g. for the environment by evaluating the information in the literature to describe the potential to enter the environment and to reach the potential ecological targets. Results indicate that the main risk for the environment is expected from metals and metal oxides, especially for algae and Daphnia, due to exposure to both, particles and ions. The main risks for human health may arise from chronic occupational inhalation exposure, especially during the activities of high particle release and uncontrolled exposure. The information on consumer and environmental exposure of humans is too scarce to attempt a quantitative risk characterisation. It is recognised that the currently available database for both, hazard and exposure is limited and there are high uncertainties in any conclusion on a possible risk. The results should therefore not be used for any regulatory decision making. Likewise, it is recognised that the REACH guidance was developed without considering the specific behaviour and the mode of action of nanomaterials and further work in the generation of data but also in the development of methodologies is required.     

A systemic health risk assessment for the chromium cycle in Taiwan

Health risk assessment (HRA) has been recognized as a useful tool for identifying health risks of human activities. In particular, this method has been well applied to spatially defined units, such as a production plant, a treatment facility, and a contaminated site. However, the management strategies based on the risk information will be more efficient if the comprehensive picture of total risks from all kinds of sources is depicted. In principle, the total risks can be obtained when all risk sources are assessed individually. Apparently, this approach demands huge amount of efforts. This study develops a methodology that combines substance flow and risk estimation to facilitate examination of risk in a systemic way and provide comprehensive understanding of risk generation and distribution corresponding to flows of substances in the anthroposphere and the environment. Substance flow analysis (SFA) and HRA method is integrated to produce a systemic risk assessment method, from which substance management schemes can be derived. In this study, the chromium cycle in Taiwan is used as an example to demonstrate the method, by which the associated substance flow in the economy and the risk caused by the substance in the environmental system is determined. The concentrations of pollutants in the environmental media, the resultant risks and hazard quotients are calculated with the widely-used CalTOX multimedia model.     

Military use of depleted uranium: assessment of prolonged population exposure

This work is an exposure assessment for a population living in an area contaminated by the use of depleted uranium (DU) weapons. RESRAD 5.91 code was used to evaluate the average effective dose at depths of 1, 10, 20 cm of contaminated soil, in a residential farming scenario. Critical pathways and groups are identified in soil inhalation and ingestion; critical group is identified in children playing with the soil. From the available information on DU released at targeted sites, both critical and average exposure can produce toxicological hazards. The annual dose limit for the population can be exceeded within a few years from DU deposition for soil inhalation. As a result, clean up at targeted sites must be planned on the basis of measured concentration, when available, while special measures must be adopted anyway to reduce unaware exposures.     

Health effects and exposure to polychlorinated biphenyls (PCBs) and metals in a contaminated community

Environmental measurements carried out by local authorities during the 1970s, 80s and 90s in an area contaminated by hundreds of years of industrial activities have revealed high levels of zinc (Zn), copper (Cu), lead (Pb) and cadmium (Cd) in soil, vegetables, root crops, berries and mushrooms. In 1972, a large quantity of oil contaminated with polychlorinated biphenyls (PCBs) was accidentally spilled into the river running through the village. To investigate the possible health effects of exposure from local sources, all cancer diagnoses, registered in 1960–2003 for individuals living in the study area, were collected from the regional cancer register of southeast Sweden. The total cancer incidence was non-significantly decreased both among males and females as compared to national rates (SIR = 0.91) for each gender. Among males, increased risks, of border-line significance, were seen for testicular cancer and lymphomas as well as significantly decreased risks for cancer in the rectum, respiratory system and brain. Information on lifetime residence, occupation, smoking habits, diseases, childbirth and food consumption, was collected via questionnaires from cancer cases and randomly selected controls. In both genders combined, significant associations were found for total cancer and high consumption of local perch, and for lymphomas and high consumption of both perch and pikeperch. Female breast cancer was significantly associated with high consumption of local perch and pike as well as with work in metal production. Mothers residing in the parish before the age of five reported significantly more preterm child deliveries. In spite of study limitations, the results indicate that residing in a rural contaminated area may contribute to the development of certain cancers and reproductive effects. In females, high consumption of local fish was shown to be the strongest determinant for total cancer, while in males, the strongest determinant was residing in the study area the first five years of life. Further research including validation of exposure using biomarkers is required to verify the findings as well as future studies in other polluted areas in Sweden with larger population bases.     

Development and application of an innovative expert decision support system to manage sediments and to assess environmental risk in freshwater ecosystems

With the aim of supporting decision makers to manage contamination in freshwater environments, an innovative expert decision support system (EDSS) was developed. The EDSS was applied in a sediment quality assessment along the Bormida river (NW, Italy) which has been heavily contaminated by an upstream industrial site for more than a century. Sampling sites were classified by means of comparing chemical concentrations with effect-based target values (threshold and probable effect concentrations). The level of each contaminant and the combined toxic pressure were used to rank sites into three categories: (i) uncontaminated (8 sites), (ii) mildly contaminated (4) and (iii) heavily contaminated (19). In heavily contaminated sediments, an environmental risk index (EnvRI) was determined by means of integrating chemical data with ecotoxicological and ecological parameters (triad approach). In addition a sediment risk index (SedRI) was computed from combining chemical and ecotoxicological data. Eight sites exhibited EnvRI values ≥ 0.25, the safety threshold level (range of EnvRI values: 0.14–0.31) whereas SedRI exceeded the safety threshold level at 6 sites (range of SedRI values: 0.16–0.36). At sites classified as mildly contaminated, sublethal biomarkers were integrated with chemical data into a biological vulnerability index (BVI), which exceeded the safety threshold level at one site (BVI value: 0.28). Finally, potential human risk was assessed in selected stations (11 sites) by integrating genotoxicity biomarkers (GTI index falling in the range 0.00–0.53). General conclusions drawn from the EDSS data include: (i) in sites classified as heavily contaminated, only a few exhibited some significant, yet limited, effects on biodiversity; (ii) restrictions in re-using sediments from heavily contaminated sites found little support in ecotoxicological data; (iii) in the majority of the sites classified as mildly contaminated, tested organisms exhibited low response levels; (iv) preliminary results on genotoxicity biomarkers indicate possible negative consequences for humans if exposed to river sediments from target areas.     

Vulnerability of human environment to risk: case of groundwater contamination risk

Based on a theoretical revision of the social vulnerability concept, this article proposes a scheme of vulnerability indicators within the human environment focused on different aetiology risks. An adaptation of this generic scheme of vulnerability factors is set for the specific field of aquifer contamination risk, as well as a methodology for its analysis. Finally, model application examples are given for the Sierra de Líbar and Sierra de Mijas carbonate aquifers and the Vélez River detrital aquifer, all of which are located in the south of Spain. Obtained cartography results show a range of utilities for risk mitigation and permit appropriate spatial discrimination for its performance over different scales. The exposure and vulnerability of the groundwater contamination risk concept is evaluated in specific maps, taking into account the resident population as well as their assets.     

三峡库区江段潜在水环境污染风险评价研究

三峡库区的水环境安全不仅关系到库区周边省市用水安全,更与长江流域的生态安全以及整个中国的可持续发展密切相关.基于压力-状态-响应(PSR)模型,综合考虑风险源危险性、风险受体敏感性以及区域环境风险可接受水平等因素构建水环境污染风险分级评价指标体系与量化方法,运用冷热点格局分析等空间统计方法,以行政区为单元综合评价三峡库区潜在水环境污染风险分布状况.结果表明:(1)云阳县风险源数量最多,万州区风险受体数量最多,但重庆主城区及周边地区高风险污染源和高敏感受体分布最为密集,且区域环境风险可接受水平最低.(2)研究区县区级风险源危险性和风险受体敏感性指标统计结果均呈集聚分布格局,热点区域集中在库区上游重庆主城区及周边地区,且该区域风险可接受水平表现为冷点区域,而在其它区域基本呈现为均衡的分布格局,未形成明显的热点或冷点区域.(3)库区水污染高风险江段包括九龙坡区、渝北区、沙坪坝区、渝中区和南岸区等5个县区,中风险江段包括长寿区、北培区、江北区、大渡口区、涪陵区、石柱县和巴东县等7个县区,低风险江段主要分布在库区上游的江津区和库区腹地及下游区域.最后,针对不同区域潜在水污染风险分布特征,从产业优化布局、预警与应急能力建设以及企业污废水处理技术升级等方面提出风险管控的相关建议.     

An assessment of urban vulnerability in the Amazon Delta and Estuary: a multi-criterion index of flood exposure,socio-economic conditions and infrastructure

The Amazon Delta and Estuary (ADE) is a region of continental and global ecological importance. Controversy, many of the basic infrastructure and services essential for quality of life and sustainable development of this delta are absent. Using a conceptual model to define socio-economic vulnerability in the urban ADE, a thorough assessment of indicators including sanitation services, housing conditions, household income, population, flood risk and unplanned settlements was conducted in 41 cities at the census sector scale (n = 2938). A multi criterion index was applied to classify urban vulnerability from three dimensions: flood exposure, socio-economic sensitivity and infrastructure. This is the first study to examine urban vulnerability within and between urban areas of the ADE. Results indicated that most of the urban sectors of the ADE are exposed to potential risks due to a combination of flood hazards, poverty and basic structural deficiencies such as insufficient drinking water or inadequate waste water collection, with several sectors being afflicted by similar problems. The assessment of vulnerability indicates that 60–90 % of the urban population live in conditions of moderate to high degree of vulnerability. The ADE cities presented a pattern where vulnerability increases from city center to their newly developed urban areas. Inadequate planning coupled with rapid urbanization has contributed to the development of unplanned settlements in almost half of the urban sectors of the ADE. Combined, these factors contribute to widespread socio-economic vulnerability along the urban spaces of the ADE, increasing exposure to health risks and more frequent seasonal and stochastic events such as storm surges and high flooding levels.