Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants. They have been identified as a type of carcinogenic substance and are relatively widespread in environment media such as air, water and soils, constituting a significant hazard for human health. In many parts of the world, PAHs are still found in high concentrations despite improved legislation and monitoring, and it is therefore vital defining their profiles, and assessing their potential sources. This study focused on a large region of the south of Italy, where concentration levels, profiles, possible sources and toxicity equivalent quantity (TEQ) level of sixteen PAHs were investigated. The survey included soils from five large regions of the south of Italy: 80 soil samples (0-20 cm top layer) from urban and rural locations were collected and analysed by gas chromatography-mass spectrometry. Total PAHs and individual molecular compounds from the US Environmental Protection Agency priority pollutants list were identified and measured. Results showed that 16 PAHs varied significantly in urban and rural areas, and different regions presented discordant characteristics. Urban areas presented concentrations ranging from 7.62 to 755 ng g (mean = 84.85 ng g), whilst rural areas presented ranges from 1.87 to 11,353 ng g (mean = 333 ng g). Large urban areas, such as Rome, Naples and Palermo, exhibited high PAHs total concentration, but high values were also found in rural areas of Campania region. Different PAHs molecular ratios were used as diagnostic fingerprinting for source identification: LWMPAHs/HWMPAHs, Fluo/(Fluo + Pyr), BaA/(BaA + Chr), Ant/(Ant +  Phe) and IcdP/(IcdP + BghiP). These ratios indicated that PAHs sources in the study area were mainly of pyrogenic origin, i.e. mostly related to biomass combustion and vehicular emission. On the other hand, values in Sicilian soils seemed to indicate a petrogenic origin, possibly linked to emissions from crude oil combustion and refineries present in the region. Finally, results allowed to calculate the toxicity equivalent quantity (TEQ) levels for the various locations sampled, highlighting that the highest values were found in the Campania region, with 661 and 54.20 ng g, in rural and urban areas, respectively. These findings, which could be linked to the presence of a large solid waste incinerator plant, but also to well-documented illegal waste disposal and burning, suggest that exposure to PAH may be posing an increased risk to human health in some of the studied areas.

Chemical elements that are either present naturally in the soil or introduced by pollution are more usefully estimated in terms of 'availability' of the element, since it is this property that can be related to mobility and uptake by plants. A good estimation of 'availability' can be achieved by measuring the concentration of the element in soil pore water. Recent achievements in analytical techniques allowed to expand the range of interest to trace elements, which play a crucial role both in contaminated and uncontaminated soils and include those defined as potentially toxic elements (PTE) in environmental studies. A complete chemical analysis of soil pore water represents a powerful diagnostic tool for the interpretation of many soil chemical phenomena relating to soil fertility, mineralogy, and environmental fate. This chapter describes some of the current methodologies used to extract soil pore water. In particular, four laboratory-based methods, i) high speed centrifugation-filtration, (ii) low (negative-) pressure Rhizon™ samplers, (iii) high pressure soil squeezing and (iv) equilibration of dilute soil suspensions, are described and discussed in detail. A number of operational factors are presented: pressure applicable (i.e., pore size involved), moisture pre-requisites of the soil, pore water yielding, efficiency, duration of extraction, materials and possible contaminations for PTE studies. Some consideration is then taken to assess advantages and disadvantages of the methods, including costs and materials availability.

a b s t r a c tThe cycling of sulfur (S), iron (Fe) and phosphorus (P) in sediments and pore water can impact the water quality of overlying water. In a heavily polluted river estuary (Yantai, China), vertical profiles of fluxes of dissolved sulfide, Fe 2þ and dissolved reactive phosphorus (DRP) in sediment pore water were investigated by the Diffusive Gradients in Thin films technique (DGT). Vertical fluxes of S, Fe, P in intertidal sediment showed the availability of DRP increased while the sulfide decreased with depth in surface sediment, indicating that sulfide accumulation could enhance P release in anoxic sediment. In sites with contrasting salinity, the relative dominance of iron and sulfate reduction was different, with iron reduction dominant over sulfate reduction in the upper sediment at an intertidal site but the reverse true in a freshwater site, with the other process dominating at depth in each case. Phosphate release was largely controlled by iron reduction.

A review on mycoremediation of petroleum-contaminated soils to identify developments, limitations and perspectives for its optimal utilization.

The concept of 'Sustainable Intensification' (SI) has been promoted as a potential solution to the many contemporary challenges facing agriculture, but has also received widespread criticism for being too narrow in scope and failing to address all aspects of sustainability. Despite this, there are few suggestions in the literature as to what a holistic, broad-based approach to SI should comprise and what issues and trade-offs are likely to arise in the adoption and operation of such a broadly-based approach. We report a suit of SI indicators suggested by UK stakeholders, evaluate the plausibility of these in terms of the commonly established principles of sustainability, and identify the critical issues that may arise in the adoption and operation of these indicators. The purpose of this paper is not to recommend a specific blueprint for SI but to raise issues and questions for dialogue amongst stakeholders. Data were collected via semi-structured interviews with 32 stakeholders from throughout the UK agrifood system. The data were analysed thematically and organised using a Social-Ecological Systems (SESs) framework. The interviewees suggested a total of 110 SI indicators, of which the most frequently suggested related to agricultural production and ecological considerations. There was less emphasis placed on social and cultural dimensions of agricultural systems. A number of the indicators suggested were poorly-defined and it was difficult to determine what particular aspects of sustainability they addressed. Many potential trade-offs between the indicators were also evident. The findings raise a number of questions. Is it appropriate to continue referring to SI as Sustainable Intensification when it fails to give equal consideration to all accepted aspects of sustainability? Would it be more appropriate to refer to the SI concept as 'Ecological Intensification'? Is a broad-based and all-encompassing definition of 'sustainability' always desirable, or should 'sustainability' be considered as context specific, with the weighting of the different dimensions varying according to operational circumstances? We argue that these questions need to be resolved through stakeholder dialogues in order for the concept of SI to become more widely accepted and implementable in practice.