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In this paper, we develop an integrated model for slacks-based measure (SBM) simultaneously of both the eciency and the super-eciency for decision-making units (DMUs) in data envelopment analysis (DEA). Unlike the traditional solution approaches in which we need to identify the ecient DMUs by the SBM model of Tone [20] before applying the super SBM model of Tone [21] for the DMUs to achieve their super-eciency scores, our integration can obtain the eciency scores of the inecient DMUs and the super-eciency scores of the ecient DMUs by solving simultaneously these two models by an onestage approach. Therefore, it may save computational time for large-scale practical applications. Due to the non-linearity in the objective function of this integrated model, we develop a linearisation technique to deal with the non-linear model. The numerical experiments, carried out on several examples in the literature and a case study, have demonstrated the accuracy and the computational time eectiveness of our proposed model as compared with the traditional solution approaches.

Concentrations of total organic carbon (TOC), total petroleum hydrocarbons, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were determined in 84 near-surface soils (5–20cm depth) taken from a 255km2 area of Glasgow in the Clyde Basin, UK, during July 2011. Total petroleum hydrocarbon range was 79–2,505mgkg–1 (mean 388mgkg–1; median 272mgkg–1) of which the aromatic fraction was 13–74 % (mean 44 %, median 43 %) and saturates were 28–87 % (mean 56 %, median 57 %). ∑16 PAH varied from 2–653mgkg–1 (mean 32.4mgkg–1; median 12.5mgkg–1) and ∑31 PAH range was 2.47–852mgkg–1 (mean 45.4mgkg–1; median 19.0mgkg–1). ∑PCBtri-hepta range was 2.2–1052μgkg–1 (mean 32.4μgkg–1; median 12.7μgkg–1) and the ∑PCB7 range was 0.3–344μgkg–1 (mean 9.8μgkg–1; median 2.7μgkg–1). The concentration, distribution and source of the persistent organic pollutants were compared with those found in urban soils from other cities and to human health assessment criteria for chronic exposure to chemicals in soil. Total concentrations encountered were generally similar to other urban areas that had a similar industrial history. Benzo[a]pyrene concentrations were assessed against four different land use scenarios (irrespective of current land use) using generic assessment criteria resulting in six of 84 samples exceeding the residential criteria. Isomeric PAH ratios and relative abundance of perylene suggest multiple and environmentally modified pyrogenic PAH sources, inferred to be representative of diffuse pollution. ∑PCB7 concentrations were exceeded in 10 % of sites using the Dutch target value of 20μgkg–1. PCB congener profiles were environmentally attenuated and generally dominated by penta-, hexa- and hepta-chlorinated congeners.

Terrestrial ecosystem risk assessment remains in its infancy by comparison with the aquatic discipline, yet it is advancing quickly in response to increasing concerns surrounding soil quality and the sustainable use of soil. Several international frameworks have been developed during the last decade to aid decision-makers as the need for scientifically derived tools for determining ecological risk from land contamination has been recognized. From the regulatory viewpoint, the priority is establishing what to protect in order to prevent ecological harm. This is a complex issue requiring clear objectives in a risk assessment context. The most important factor in assessing ecological harm is whether or not ecosystem function is altered as a result of land contamination and, if it is, judging the significance. A consensus is developing that ecological risk assessment should aim to protect populations rather than individuals. This paper critically reviews recent developments in risk assessment for terrestrial ecosystems and land contamination in the UK, with emphasis on deriving a measure of ecological harm to assess ecosystem function. We seek to further justify the use of earthworms as a favoured indicator species for protecting ecological function. Guidance on how to measure harm in relation to ecological function is, however, still lacking.