Editorial handling by M. Kersten a b s t r a c tSurface soils from a 19 km 2 area in east London, UK were analysed for polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB) (n = 76).P 16 PAH ranged from 4 to 67 mg/kg (mean, 18 mg/ kg) and P 50 PAH ranged from 6 to 88 mg/kg (mean, 25 mg/kg).P 7 PCB ranged from 1 to 750 lg/kg (mean, 22 lg/kg) and P tri-hepta PCB ranged 9 to 2600 lg/kg (mean, 120 lg/kg). Compared to other international cities concentrations were similar for PAH but higher for PCB. Normal background concentrations (NBC) were calculated and compared to risk-based human health generic assessment criteria (GAC). Benzo[a]pyrene NBC for urban (6.9 mg/kg), semi-urban (4.4 mg/kg) and urban + semi urban (6 mg/kg) domains exceed residential (1 mg/kg) and allotment (2.2 mg/kg) LQM/CIEH GAC (at 6% SOM) and the Indeno[1,2,3-cd]pyrene NBC for urban (6.8 mg/kg) and urban + semi-urban (5.2 mg/kg) domains exceed the residential (4.2 mg/kg) LQM/CIEH GAC (at 6% SOM). Capsule Abstract: Normal background concentrations of polycyclic aromatic hydrocarbons and polychlorinated biphenyls are elevated in east London soils and in some cases exceed regulatory assessment criteria.

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21This paper provides an overview of regional geochemical mapping using stream 22 sediments from central and south-western Nigeria. A total of 1569 stream sediment 23 samples were collected and 54 major and trace elements determined by ICP-MS and 24Au, Pd and Pt by fire assay. Geostatistical techniques (e.g. correlation analysis and 25 principal factor analysis) were used to explore the data, following appropriate data 26 transformation, to understand the data structure, investigate underlying processes 27 controlling spatial geochemical variability and identify element associations.

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