Minerals stabilize organic carbon (OC) in sediments, thereby directly affecting global climate at multiple scales, but how they do it is far from understood. Here we show that manganese oxide (Mn oxide) in a water treatment works filter bed traps dissolved OC as coatings build up in layers around clean sand grains at 3%w/wC. Using spectroscopic and thermogravimetric methods, we identify two main OC fractions. One is thermally refractory (>550 °C) and the other is thermally more labile (<550 °C). We postulate that the thermal stability of the trapped OC is due to carboxylate groups within it bonding to Mn oxide surfaces coupled with physical entrapment within the layers. We identify a significant difference in the nature of the surface-bound OC and bulk OC . We speculate that polymerization reactions may be occurring at depth within the layers. We also propose that these processes must be considered in future studies of OC in natural systems.

Abstract. It is increasingly understood that the physical environment remains an important determinant of area-level health and spatial and socioeconomic health inequalities. Existing research has largely focused on the health effects of differential access to green space, the proximity of waste facilities, or air pollution. The role of brownfield-or previously developed-land has been largely overlooked. This is the case even in studies that utilise multiple measures of environmental deprivation. This paper presents the results of the first national-scale empirical examination of the association between brownfield land and morbidity and mortality, using data from England. 434C Bambra, S Robertson, A Kasim and coworkers mortality ratios from 1998/99 to 2002/03 were examined using linear mixed modelling (adjusting for potential environmental, socioeconomic, and demographic confounders). A significant and strong, adjusted, area-level association was found between brownfield land and morbidity: people living in wards with a high proportion of brownfield land are significantly more likely to suffer from poorer health than those living in wards with a small proportion of brownfield land. This suggests that brownfield land could potentially be an important and previously overlooked independent environmental determinant of population health in England. The remediation and redevelopment of brownfield land should therefore be considered as a public health policy issue.

The fate of organic matter through watersheds has been shown to be an important component of the global carbon cycle and processes in rivers can rapidly transfer carbon from the terrestrial biosphere to the atmosphere. However, the role of water abstraction in diverting organic matter from freshwater has not been considered. This study used two methods to estimate the amount of organic carbon removed by water treatment processes, first, by estimating the amount of carbon that has to be removed given the abstracted volumes and the freshwater composition; and, second, estimated from reports of the production and composition of water treatment residuals from water companies. For the UK, the median total organic carbon removed by water abstraction was 46 ktonnes C/yr, this equates to a median per capita value of 0.76 kg C/ca/yr. The median total organic nitrogen removed was 4.0 ktonnes N/yr, equivalent to 0.07 kg N/ca/yr. The removal of TOC by water abstraction represents 1.5% of the total removal rate across UK watersheds. The release of greenhouse gases from UK rivers is now estimated to be between 12,754 and 32,332 ktonnes CO2eq/yr equivalent to between 55 and 127 tonnes CO2eq/km2/yr with fluvial organic matter between 8800 and 15,116 ktonnes CO2eq/yr in the proportion 6:86:8 N2O:CO2:CH4. The emissions factor for 1 tonne of organic carbon entering the UK fluvial network has a median value of 2.95 tonnes CO2eq/yr with a 5th to 95th percentile range of 2.55 to 3.59 tonnes CO2eq/yr. Globally, a per capita values for countries with municipal treated water supply would be 0.8 to 0.86 kg C/ca/yr.

A natural Mn oxide (NMO) waste was assessed as an in situ remediation amendment for Pb contaminated sites. The viability of this was investigated using a 10 month lysimeter trial, wherein a historically Pb contaminated soil was amended with a 10% by weight model NMO. The model NMO was found to have a large Pb adsorption capacity (qmax 346±14 mg g(-1)). However, due to the heterogeneous nature of the Pb contamination in the soils (3650.54-9299.79 mg kg(-1)), no treatment related difference in Pb via geochemistry could be detected. To overcome difficulties in traditional geochemical techniques due to pollutant heterogeneity we present a new method for unequivocally proving metal sorption to in situ remediation amendments. The method combines two spectroscopic techniques; namely electron probe microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS). Using this we showed Pb immobilisation on NMO, which were Pb free prior to their addition to the soils. Amendment of the soil with exogenous Mn oxide had no effect on microbial functioning, nor did it perturb the composition of the dominant phyla. We conclude that NMOs show excellent potential as remediation amendments.

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