Paul Nathanail

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.

A Study of the relationship between arsenic bioaccessibility and its solid-phase distribution in soils from Wellingborough, UK

Twenty samples from soils developed over the Northampton Sand ironstone formation were collected from, in and around the town of Wellingborough, Northamptonshire, UK. The total arsenic (As) content ranged from ca. 20–100 mg kg− 1and the bioaccessible As content, as measured by a physiologically based in vitro extraction test, ranged from 1 to 6 mg kg− 1. A chemometric algorithm for mixture resolution, when applied to total element and total organic carbon concentration of the soils, was able to identify chemically distinct soil constituents and their associated As content. Multiple linear regression (MLR) modelling, using the As content of the intrinsic soil constituents and their first order interactions as independent variables, was able to predict the bioaccessible As content of the soils (R2 = 0.85) with an uncertainty of 1.33 mg kg− 1. Although the MLR model showed that the interactions between the soil constituents were the key factors controlling the bioaccessible fraction in each soil most of the total As was found to be bound to an Fe oxide soil constituent. The model predictions shown are currently only valid for the geological and soil chemical setting investigated here, extrapolation to other geological settings would require additional investigations.

Generic Assessment Criteria for human health risk assessment of potentially contaminated land in China

Generic Assessment Criteria (GAC) are derived using widely applicable assumptions about the characteristics and behaviour of contaminant sources, pathways and receptors. GAC provide nationally consistent guidance, thereby saving money and time. Currently, there are no human health based Generic Assessment Criteria (GAC) for contaminated sites in China. Protection of human health is therefore difficult to ensure and demonstrate; and the lack of GAC makes it difficult to tell if there is potential significant risk to human health unless site-specific criteria are derived. This paper derived Chinese GAC (GAC) for five inorganic and eight organic substances for three regions in China for three land uses: urban residential without plant uptake, Chinese cultivated land, and commercial/industrial using the SNIFFER model. The SNIFFER model has been further implemented with a dermal absorption algorithm and the model default input values have been changed to reflect the Chinese exposure scenarios. It is envisaged that the modified SNIFFER model could be used to derive GAC for more contaminants, more Regions, and more land uses. Further research to enhance the reliability and acceptability of the GAC is needed in regional/national surveys in diet and working patterns.

A Deterministic Method for Deriving Site-Specific Human Health Assessment Criteria for Contaminants in Soil

Abstract A method for deriving Site-Specific Assessment Criteria (SSAC) for use when considering risk to human health from chronic exposure to heavy metals (except lead), metalloids, and organic substances in soil, with application to the United Kingdom (UK), is described. The SSAC represents the soil concentration above which an unacceptable risk to human health may be indicated. The method considers the UK standard land uses (residential with and without plant uptake, allotment gardens, and commercial/industrial) by applying the default exposure factors and algorithms provided. Non-standard land uses can be also considered. Site-specific determinations of contaminant bioaccessibility or of plant-to-soil concentration factors may be used if available. The method adopts the risk-based source-pathway-receptor pollutant linkage framework and a deterministic methodology. Exposure pathways considered are direct ingestion of soil and dust, consumption of home grown or allotment vegetables, ingestion of soil attached to such vegetables, inhalation of soil vapors outdoors and inhalation of soil vapors indoors. A test for the significance of the dermal pathway is also included. It is not intended that the method be used to generate or replace UK Soil Guideline Values, because this can only be done by the appropriate authoritative bodies within the UK (Department of the Environment, Food and Rural Affairs and the Environment Agency).

Towards bioavailability-based soil criteria: past, present and future perspectives

Bioavailability has been used as a key indicator in chemical risk assessment yet poorly quantified risk factor. Worldwide, the framework used to assess potentially contaminated sites is similar, and the decisions are based on threshold contaminant concentration. The uncertainty in the definition and measurement of bioavailability had limited its application to environment risk assessment and remediation. Last ten years have seen major developments in bioavailability research and acceptance. The use of bioavailability in the decision making process as one of the key variables has led to a gradual shift towards a more sophisticated risk-based approach. Now a days, many decision makers and regulatory organisations ‘more readily accept’ this concept. Bioavailability should be the underlying basis for risk assessment and setting remediation goals of those contaminated sites that pose risk to environmental and human health. This paper summarises the potential application of contaminant bioavailability and bioaccessibility to the assessment of sites affected by different contaminants, and the potential for this to be the underlying basis for sustainable risk assessment and remediation in Europe, North America and Australia over the coming decade.

Sustainable development and brownfield regeneration. What defines the quality of derelict land recycling

Abstract Brownfield regeneration, involving the reintegration of derelict and abandoned sites into their economic environments, is a key element of sustainable urban development. To realize the full potential brownfield regeneration offers to sustainable urban development, the parameters that influence the degree of sustainability within brownfield regeneration itself have to be understood. An analysis of eight sites in four European countries identified strengths and weaknesses in current brownfield regeneration practice. Among other outcomes, criteria for sustainable brownfield projects and the “Sustainability Assessment Tool for brownfield regeneration projects” (SAT) were developed. The tool is based on a framework of objectives, indicators and best practices that reflect the multi-dimensional and multi-stakeholder complexity that characterizes brownfield regeneration. The SAT would be one option to implement sustainability criteria without waiving the local and regional context. The SAT offers one way for brownfield projects being put forward for public and specifically European Union, funding to be evaluated. This would be a remarkable innovation, leading to not only more efficient use of public money but also an increase in quality of brownfield regeneration.

China's soil and groundwater management challenges: Lessons from the UK's experience and opportunities for China.

There are a number of specific opportunities for UK and China to work together on contaminated land management issues as China lacks comprehensive and systematic planning for sustainable risk based land management, encompassing both contaminated soil and groundwater and recycling and reuse of soil. It also lacks comprehensive risk assessment systems, structures to support risk management decision making, processes for verification of remediation outcome, systems for record keeping and preservation and integration of contamination issues into land use planning, along with procedures for ensuring effective health and safety considerations during remediation projects, and effective evaluation of costs versus benefits and overall sustainability. A consequence of the absence of these overarching frameworks has been that remediation takes place on an ad hoc basis. At a specific site management level, China lacks capabilities in site investigation and consequent risk assessment systems, in particular related to conceptual modelling and risk evaluation. There is also a lack of shared experience of practical deployment of remediation technologies in China, analogous to the situation before the establishment of the independent, non-profit organisation CL:AIRE (Contaminated Land: Applications In Real Environments) in 1999 in the UK. Many local technology developments are at lab-scale or pilot-scale stage without being widely put into use. Therefore, a shared endeavour is needed to promote the development of technically and scientifically sound land management as well as soil and human health protection to improve the sustainability of the rapid urbanisation in China.

Bioavailability—the underlying basis for risk-based land management

Contaminated sites represent a growing challenge. Globally, there are more than 3,000,000 potentially contaminated sites which represent a lost economic opportunity and threat to the health and wellbeing of humans and the environment. Environmental contamination is the legacy of industrialization and insufficient environmental legislation and enforcement. At the biennial International Committee on Contaminated Land, theWorld Bank reported that it had integrated contamination in its BGreening Development and Sustainable Urban Development^ Agenda. The potential impact of industrial pollutants on human health was only recognised following mass poisoning of people via ingestion of toxic metals including cadmium (Cd), arsenic (As) and lead (Pb) (Naidu et al. 1996). Although site contamination was recognised as early as the 1960s, less than a tenth of potentially contaminated sites have been remediated due to the complex and challenging nature of both surface and subsurface contamination. These challenges are further exacerbated by cost and technical impracticability associated with contaminants present in mixtures and those that are recalcitrant and persist. Common contaminants include petroleum hydrocarbons, chlorinated solvents, pesticides, inorganics, heavy metals and radioactive wastes. These can be found in a variety of sites such as oil and gas operations, mines, industrial complexes, landfills, waterways and harbours. However, in most countries, the scale of the problem is difficult to assess, as the definition of Bcontaminated land^ or Bsite contamination^ has often been subjective or poorly defined, even in statute. Only limited efforts have been made to develop an inventory of contaminated sites in developing countries although industrial practices and the societal drive for economic growth continues to increase environmental contamination due to disposal of wastes into land and water bodies. Although, most developing countries have stringent regulatory guidelines, adherence to and regulation of these is a major problem. The rapid expansion of the urban fringe due to mass migration of people from rural into urban areas is causing significant pressure on available land for residential properties. Thus, expansion is being driven onto disused former industrial zones. Such expansion has led to a significant demand for remediation and indeed cost-effective and sustainable techniques for managing Responsible editor: Philippe Garrigues

An emerging market for groundwater remediation in China: Policies, statistics, and future outlook

There is a rapidly emerging and potentially huge market for the remediation of contaminated groundwater in China. The Chinese government published a Water Action Plan in April 2015, a Soil Action Plan in May 2016, and a draft Soil Pollution Prevention and Control Law in June 2017. All of these new policies and regulations put pressures on local governments and contaminated site owners, obliging them to conduct site investigation and to cleanup contaminated groundwater. The Chinese population in northern regions heavily depend on groundwater, with nearly 70% of water supply coming from aquifer sources in the Beijing-Tianjin-Hebei region. However, poor groundwater quality due to natural geochemical background and anthropogeic pollution is a serious concern, with poor or very poor quality water observed in nearly 80% of groundwater monitoring wells in 17 northern provinces. Shallow groundwater in many areas has been contaminated by toxic pollutants such as heavy metals and chlorinated organic compounds. There is an urgent need to better understand the situation and to conduct groundwater remediation at contaminated sites. The Chinese government is investing heavily in the research and development for groundwater remediation, which is expected to greatly add to the quality and quantity of groundwater remediation projects in the near future.