Environmental behaviour of iron and steel slags in coastal settings.

Iron and steel slags have a long history of both disposal and beneficial use in the coastal zone. Despite the large volumes of slag deposited, comprehensive assessments of potential risks associated with metal(loid) leaching from iron and steel by-products are rare for coastal systems. This study provides a national-scale overview of the 14 known slag deposits in the coastal environment of Great Britain (those within 100 m of the mean high-water mark), comprising geochemical characterisation and leaching test data (using both low and high ionic strength waters) to assess potential leaching risks. The seaward facing length of slag deposits totalled at least 76 km, and are predominantly composed of blast furnace (iron-making) slags from the early to mid-20th Century. Some of these form tidal barriers and formal coastal defence structures, but larger deposits are associated with historical coastal disposal in many former areas of iron and steel production, notably the Cumbrian coast of England. Slag deposits are dominated by melilite phases (e.g. gehlenite), with evidence of secondary mineral formation (e.g. gypsum, calcite) indicative of weathering. Leaching tests typically show lower element (e.g. Ba, V, Cr, Fe) release under seawater leaching scenarios compared to deionised water, largely ascribable to the pH buffering provided by the former. Only Mn and Mo showed elevated leaching concentrations in seawater treatments, though at modest levels (<3 mg/L and 0.01 mg/L, respectively). No significant leaching of potentially ecotoxic elements such as Cr and V (mean leachate concentrations <0.006 mg/L for both) were apparent in seawater, which micro-X-Ray Absorption Near Edge Structure (µXANES) analysis show are both present in slags in low valence (and low toxicity) forms. Although there may be physical hazards posed by extensive erosion of deposits in high-energy coastlines, the data suggest seawater leaching of coastal iron and steel slags in the UK is likely to pose minimal environmental risk.

Microwave Sensors for In Situ Monitoring of Trace Metals in Polluted Water.

Thousands of pollutants are threatening our water supply, putting at risk human and environmental health. Between them, trace metals are of significant concern, due to their high toxicity at low concentrations. Abandoned mining areas are globally one of the major sources of toxic metals. Nowadays, no method can guarantee an immediate response for quantifying these pollutants. In this work, a novel technique based on microwave spectroscopy and planar sensors for in situ real-time monitoring of water quality is described. The sensors were developed to directly probe water samples, and in situ trial measurements were performed in freshwater in four polluted mining areas in the UK. Planar microwave sensors were able to detect the water pollution level with an immediate response specifically depicted at three resonant peaks in the GHz range. To the authors' best knowledge, this is the first time that planar microwave sensors were tested in situ, demonstrating the ability to use this method for classifying more and less polluted water using a multiple-peak approach.

Critical Shifts in Trace Metal Transport and Remediation Performance under Future Low River Flows.

Exceptionally low river flows are predicted to become more frequent and more severe across many global regions as a consequence of climate change. Investigations of trace metal transport dynamics across streamflows reveal stark changes in water chemistry, metal transformation processes, and remediation effectiveness under exceptionally low-flow conditions. High spatial resolution hydrological and water quality datasets indicate that metal-rich groundwater will exert a greater control on stream water chemistry and metal concentrations because of climate change. This is because the proportion of stream water sourced from mined areas and mineralized strata will increase under predicted future low-flow scenarios (from 25% under Q45 flow to 66% under Q99 flow in this study). However, mineral speciation modelling indicates that changes in stream pH and hydraulic conditions at low flow will decrease aqueous metal transport and increase sediment metal concentrations by enhancing metal sorption directly to streambed sediments. Solute transport modelling further demonstrates how increases in the importance of metal-rich diffuse groundwater sources at low flow could minimize the benefits of point source metal contamination treatment. Understanding metal transport dynamics under exceptionally low flows, as well as under high flows, is crucial to evaluate ecosystem service provision and remediation effectiveness in watersheds under future climate change scenarios.

Commitment of juvenile myelo-monocytic (JMML) leukemic cells to spontaneously differentiate into dendritic cells.

Juvenile myelo-monocytic leukemia (JMML) is a severe malignant stem cell disorder of childhood. A proportion of cells from JMML mononuclear cells (MNC) spontaneously differentiate in vitro into dendritic cells (DC). We have studied MNC from 14 JMML patients, and characterized their functional activity as antigen presenting cells (APC). Large cells, differentiated after seven days of culture, expressed high levels of MHC II molecules and Mannose Receptor, variable levels of CD80 and CD86, and low levels of CD1a. Similar to immature DC, cells from JMML had high levels of dextran endocytosis, and were able to elicit proliferation of allogeneic T lymphocytes in mixed leukocyte reaction (MLR). CD40L-matured DC from JMML was associated with relevant increase of CD80, CD86 and CD83, increased APC activity, responded in chemotaxis assays to MIP-3beta and secreted increased amounts of macrophage derived chemokine (MDC). Immature DC and CD40L-matured DC from JMML produced very low amounts of IL-12, whereas the production of IL-10 was higher than normal DC. In line with these findings, they showed defective capacity to polarize naive T cells to differentiate into Th1 effectors. These results indicate that MNC from JMML are committed to spontaneously differentiate into DC with morphological and phenotypical characteristics similar to normal DC. The cytokine profile produced by these APC is likely to suppress and not to elicit a protective immune response.