Fe-sulphate-rich evaporative mineral precipitates from the Río Tinto, southwest Spain

Buckby, T.; Black, Stuart; Coleman, Max; Hodson, Mark E.

doi:10.1180/0026461036720104

Cited by 163 publications

(114 citation statements)

References 17 publications

Supporting

Mentioning

107

Contrasting

Unclassified

Order By: Relevance

“…The greatest increase in dissolved Zn concentration is closest to the sediment/water interface. It is possible that over prolonged dry periods, the evaporation of pore water and chemical saturation of solutes could have promoted the formation of soluble metal sulphate minerals (Alastuey et al 1999;Harris et al 2003;Buckby et al 2003;Nordstrom 2009). The dissolution of these salts on first flood wetting could account for the high concentrations of dissolved Zn released into pore water at the start of a flood.…”

Section: Discussionmentioning

confidence: 99%

“…Contrary to the 3wwet run, it is unlikely that the oxidation of previously reduced Mn (hydr)oxide minerals would have provided a solubility control over the release of dissolved Zn concentrations, particularly at the start of a flood. Therefore, the sediment could, within hours, become a significant source of Zn contamination following prolonged dry periods due to formation of soluble sulphate minerals (Buckby et al 2003;Nordstrom 2009) and the dissolution of these salts on flooding. Studies have described a 'spike' in trace metal concentrations on the rising limb of river discharge during storm events due to the dissolution and 'flushing' of salts back into river channels following long dry antecedent periods (Nordstrom 2011).…”

Section: Discussionmentioning

confidence: 99%

“…Several possible geochemical mechanisms for the release of dissolved Fe into pore water are: the oxidation of impure sphalerite (Heidel et al 2013), oxidation of sphalerite coupled to the reduction of ferric Fe (Eq. 1) (Hofmann and Schuwirth 2008), or the dissolution of soluble Fe sulphate minerals such as melanterite (Fe 2 SO 4 ·7H 2 O) (Alastuey et al 1999;Buckby et al 2003;Nordstrom 2009). …”

Section: Discussionmentioning

confidence: 99%

“…During high flow events, contaminated sediment can be eroded from riverbanks and floodplains and re-introduce particulate forms of Zn back into the river channel (Dennis et al 2003;Young et al 2007). However, more bioavailable, dissolved Zn can be re-introduced where river stage variability and riverbank inundation results in changes in redox potential and drying of sediment (Buckby et al 2003;Du Laing et al 2009;Lynch et al 2014).…”

Section: Responsible Editor: Marcel Van Der Perkmentioning

confidence: 99%

See 3 more Smart Citations

Critical control of flooding and draining sequences on the environmental risk of Zn-contaminated riverbank sediments

2017

View full text Add to dashboard Cite

Purpose Diffuse pollution emanating from metal miningimpacted sediment could serve as a barrier to achieving European Union Water Framework Directive and US Clean Water Act requirements. UK climate projections (UKCP09) predict increases in rainfall and aridity that will influence river stage alternately exposing and submersing contaminated riverbank sediment. Research focuses on the environmental contaminant dissolved Zn and investigates patterns of release, key geochemical mechanisms controlling Zn mobilisation and the environmental risk of sediment subjected to these perturbations. Materials and methods Using two laboratory mesocosm experiments, metal mining-contaminated sediment was subjected to alternate wet and dry sequences of different duration and frequency. The first experiment was run to determine the influence of submersion and exposure of contaminated sediment on releases of Zn and to establish environmental risk. The second experiment utilised diffusional equilibration in thin film (DET) to observe the patterns of Zn release, with depth, in the sediment. Pore water chemical analysis at the sediment-water interface enabled elucidation of key geochemical mechanisms of control of Zn mobilisation.Results and discussion Patterns of Zn release were found to be different, depending on the length of wet and dry period. High concentrations of dissolved Zn were released at the start of a flood for runs with longer dry periods. A buildup of soluble Zn sulphate minerals over long dry periods followed by dissolution on first flood wetting was a key geochemical mechanism controlling Zn release. For longer wet runs, increases in dissolved Mn and Zn were observed over the flood period. Key geochemical mechanisms controlling Zn mobilisation for these runs were: (i) reductive dissolution of Mn (hydr)oxides and release of partitioned Zn over prolonged flood periods followed by (ii) oxidation and precipitation of Mn (hydr)oxides and sorption of Zn on exposure to atmospheric conditions. Conclusions Mesocosm experiments were a first step in understanding the effects of UK climate projections on the riverbank environment. Contaminated sediment was found to pose a significant environmental risk in response to hydrological perturbations. The 'transient' nature of dissolved Zn release could make identifying the exact sources of pollution a challenge; therefore, further field studies are advised to monitor contaminant releases under a range of hydrological conditions and account for complex hydrology at mining sites.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Responsible Editor: Marcel Van Der Perkmentioning

confidence: 99%

See 2 more Smart Citations

Critical control of flooding and draining sequences on the environmental risk of Zn-contaminated riverbank sediments

2017

View full text Add to dashboard Cite

show abstract

“…Changes in redox potential and drying (critical processes within the river floodplain environment) have been found to cause the dissolution and precipitation of iron and manganese [20,[25][26][27], sulphur [10] and sulphate [28,29] minerals that are ubiquitous in mining contaminated environments [30][31][32][33][34][35]. Such changes influence contaminant trace metal mobility [36,37].…”

Section: Introductionmentioning

confidence: 99%

Environmental Risk of Metal Mining Contaminated River Bank Sediment at Redox-Transitional Zones

2014

View full text Add to dashboard Cite

Diffuse metal pollution from mining impacted sediment is widely recognised as a potential source of contamination to river systems and may significantly hinder the achievement of European Union Water Framework Directive objectives. Redox-transitional zones that form along metal contaminated river banks as a result of flood and drought cycles could cause biogeochemical changes that alter the behaviour of polyvalent metals iron and manganese and anions such as sulphur. Trace metals are often partitioned with iron, manganese and sulphur minerals in mining-contaminated sediment, therefore the dissolution and precipitation of these minerals may influence the mobility of potentially toxic trace metals. Research indicates that freshly precipitated metal oxides and sulphides may be more "reactive" (more adsorbent and prone to dissolution when conditions change) than older crystalline forms. Fluctuations at the oxic-anoxic interface brought about through changes in the frequency and duration of flood and drought episodes may therefore influence the reactivity of secondary minerals that form in the sediment and the flux of dissolved trace metal release. UK climate change models predict longer dry periods for some regions, interspersed with higher magnitude flood events. If we are to fully comprehend the future environmental risk these climate change events pose to mining impacted river systems it is recommended that research efforts focus on identifying the primary controls on trace metal release at the oxic-anoxic interface for flood and drought cycles of different duration and frequency. This paper critically reviews the literature regarding biogeochemical processes that occur at different temporal scales during oxic, OPEN ACCESSMinerals 2014, 4 53 reducing and dry periods and focuses on how iron and sulphur based minerals may alter in form and reactivity and influence the mobility of trace metal contaminants. It is clear that changes in redox potential can alter the composition of secondary iron and sulphur minerals and influence the sorption of toxic trace metals and susceptibility to dissolution when further redox potential changes occur. However further work is needed to determine: (i) The extent to which different duration and frequency of wet and dry cycles influences the dissolution and precipitation of iron and sulphur minerals in mining contaminated river bank sediment; (ii) The temporal effects on mineral reactivity (sorption capacity and susceptibility to dissolution); (iii) The key biogeochemical processes that control the mobility of contaminant trace metals under these dynamic redox potential conditions.

show abstract

Editorial: terrestrial geochemical sediments and geomorphology

McLaren

Nash

Goudie

2004

Earth Surf Processes Landf

View full text Add to dashboard Cite

Fe-sulphate-rich evaporative mineral precipitates from the Río Tinto, southwest Spain

Cited by 163 publications

References 17 publications

Critical control of flooding and draining sequences on the environmental risk of Zn-contaminated riverbank sediments

Critical control of flooding and draining sequences on the environmental risk of Zn-contaminated riverbank sediments

Environmental Risk of Metal Mining Contaminated River Bank Sediment at Redox-Transitional Zones

Editorial: terrestrial geochemical sediments and geomorphology

Contact Info

Product

Resources

About