Total organic carbon (TOC), black carbon (BC), total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB) were determined in 73 surface (0-2 cm) and subsurface (5-20 cm) soil samples taken from a 142 km2 area in Central London, UK. Soils were assessed to provide a baseline chemistry for site owners, developers, occupiers and regulators involved in understanding the potential risk to human health and the environment. TOC range was 1.75-11.85 % (mean 5.82 %), BC 3.72-32.71 mg.g-1 (mean 13.8 mg.g-1), TPH 72-4673 mg.g-1 (mean 443 mg.g-1), Σ16PAH 1.64-421.23 mg.g-1 (mean 47.99 mg.g-1) and Σ7PCB 2.56-148.72 µg.kg-1 (mean 20.82 µg.kg-1). Surface soils were less polluted than sub-surface soils due to a decline in industry, power generation, coal burning and traffic. PAH and PCB showed a stronger affinity for BC than TOC and were higher than many other international cities. South east London (Greenwich, Woolwich, Deptford) had the highest PAH pollution. Source PAH ratios confirmed a combustion/urban road run-off origin with minor petroleum inputs. Random Forest spatial modelling (machine learning) revealed large scale pollution trends across London soils. Normal background concentrations (NBC) were calculated and compared to risk-based human health generic assessment criteria (GAC). Benz[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, and dibenzo[a]anthracene exceeded the Land Quality Management GACs for three land uses (residential, allotments and public open space near residential housing). The NBC determined for ∑7PCBs (110 µg.kg-1) and dioxin-like PCB 118 (59 µg.kg-1) exceeded the residential and allotment soil guideline values.
|Journal||Advances in Environmental and Engineering Research|
|Publication status||Published - 28 May 2021|
Research Beacons, Institutes and Platforms
- Henry Royce Institute