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1、CWR 6252 BIOGEOCHEMISTRY OF TRACE METALSMANGANESE A GROUNDWATER POLLUTION INDICATOR OR NATURAL GROUNDWATER CHEMISTRY?19th April 2010Padraic MulroyINTRODUCTIONANTHROPOGENIC INPUTAIRSOIL & SEDIMENTWATERBIOCONCENTRATION IN BIOTAHUMAN TOXICITYINFLUENCE OF REDOX & pHELEVATED LEVELS IN POLLUTED GR

2、OUNDWATER NATURAL ELEVATED LEVELS IN BEDROCKCONCLUSIONSPRESENTATION OVERVIEW1 Introduction2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels in polluted groundwater10 Natural elevated levels in bedrock11 ConclusionsI

3、NTRODUCTION1 Introduction2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels in polluted groundwater10 Natural elevated levels in bedrock11 ConclusionsGroup 7Reddish grey/silver brittle elementOxidation states of +1,

4、+2, +3, +4, +6 and +7Omnipresent 0.1% of Earths crust12th most abundant element (Iron more abundant) INTRODUCTION1 Introduction2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels in polluted groundwater10 Natural elev

5、ated levels in bedrock11 ConclusionsINTRODUCTION1 Introduction2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels in polluted groundwater10 Natural elevated levels in bedrock11 ConclusionsPrincipal ores Pyrolusite (Mn

6、O2) and Rhodocrosite (MnCO3)Large deposits in Cuyuna Range (Minnesota), Ukraine, Georgia, ChinaCommon constituent of sedimentary rocks such as shales (southeast of Ireland) ACICULAR/RADIALDENDRITICINTRODUCTION1 Introduction2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Hum

7、an Toxicity8 Influence of Redox & pH9 Elevated levels in polluted groundwater10 Natural elevated levels in bedrock11 ConclusionsManganese nodules rock concretions on sea bottom (concentric layers of Mn & Fe hydroxides)Contain Mn (27-30%), Fe (6%), Ni (1.25-1.5%), copper (1-1.4%) & cobalt

8、 (0.2-0.25%)Possible future mineral resource? OCEAN FLOORCROSS-SECTIONPOSSIBLE HARVESTING?ANTHROPOGENIC INPUT Municipal WWTP discharges to aquatic systems Application of biosolids to land & marine dumping Mining & mineral processing Air emissions: alloy, steel & iron production, combusti

9、on of fossil fuels Combustion of unleaded petrol with anti-knocking agent Methylcyclopentadienyl manganese tricarbyl (MMT) Canadian problem?1 Introduction2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels in polluted

10、 groundwater10 Natural elevated levels in bedrock11 ConclusionsAIR Concentrations in air Remote: 0.5-14ng/m3 Rural: 40ng/m3 Urban: 65-166ng/m3 Highest in source dominated areas up to 8,000ng/m3 Annual averages near foundries 200-300ng/m31 Overview2 Anthropogenic Input3 Air4 Soil & sediment5 Wate

11、r6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels in polluted groundwater10 Natural elevated levels in bedrock11 ConclusionsSOIL & SEDIMENTConcentrations in soilRange 1-4,000mg/kgAverage 300-600mg/kgSources:CrustalAtmospheric depositionRun-off from plant and other

12、 surfacesLeaching from plant tissueLeaves, dead plantAnimal material detritus & excrementSources of Mn2+ Anaerobic environmentNatural weathering of Mn2+ mineralsNaturally acidic environmentsSedimentation factorsOxygen concentration in overlying water columnPenetration of O2 into sedimentBenthic

13、organic carbon supply1 Overview2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels in polluted groundwater10 Natural elevated levels in bedrock11 ConclusionsWATER Concentrations in natural waters Range 1-10,000g/litre

14、 Average 200g/litre Concentrations in unpolluted river sediments Range 410-6,700g/litre Urban lake in vicinity of old mine tailings dump Sediment 13,400mg/kg Intertidal mudflats Range 100-1,000mg/kg Unpolluted Dundalk mudflat 421mg/kg Baltic Sea Ferromanganese Nodule Area Range 3,550-8,960mg/kg1 Ove

15、rview2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels in polluted groundwater10 Natural elevated levels in bedrock11 ConclusionsBIOCONCENTRATION Bioconcentration at lower trophic levels BCF 2,000-20,000 for marine/

16、freshwater plants BCF 800-830 for intertidal mussels BCF 35-930 for fish Uptake increases with increasing temperature but decreases with increasing pH Dissolved O2 No effect Concentration of Mn in fish flesh Range: 100mg/kg in polluted waters) Essential nutrient for terrestrial plants Requirements:

17、10-50mg/kg tissue Members of Ericaceae family (includes blueberries) are recognized hyper-accumulators1 Overview2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels in polluted groundwater10 Natural elevated levels in

18、bedrock11 ConclusionsHUMAN TOXICITY Adverse effects in humans via inhalation neurotoxin causing ataxia, co-ordination impairment, anxiety, dementia, mask-like face, involuntary movements, similar to Parkinsons disease Manganism or Welders Disease inhalation of toxic welding rod fumes not age depende

19、nt Mangasim found in farmers exposed to Manganese containing pesticides e.g. maneb (fungicide), rotenone (a insecticide) Level of manganese found in groundwater supplies in Ireland/US far below average daily intake of manganese from food Neurological effects were observed in the elderly within a gro

20、up of families exposed to elevated manganese. No effect on youngest.1 Overview2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels in polluted groundwater10 Natural elevated levels in bedrock11 ConclusionsINFLUENCE OF

21、pH & REDOX1 Overview2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels in polluted groundwater10 Natural elevated levels in bedrock11 ConclusionsMnO2 (Pyrolusite) stable compound at high redox regardless of pHMnC

22、O3 (Rhodocrosite) stable over a wide redox and pH range if carbonate is highMnO2-CO2-H2O-S2-O2 INFLUENCE OF pH & REDOX1 Overview2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels in polluted groundwater10 Natural

23、 elevated levels in bedrock11 ConclusionsHmatite, iron(III) oxide (Fe2O3) dominance shows Fe oxidises more readily in natural environmentHmatite stable in presence of Mn2+ over wide pH rangePrecipitation of Mn2+ will happened with increasing pH if carbonate or silica is present If environmental beco

24、mes more oxidising, Mn will precipitate as one of oxides MnO2 most stableMnO2-CO2-H2O-S2-O2 ELEVATED LEVELS IN POLLUTED GROUNDWATER1 Overview2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels inpolluted groundwater10

25、 Natural elevated levels in bedrock11 ConclusionsCASE STUDY AGroundwater in vulnerable upland area polluted with septate from neighbours malfunctioning on-site WWTPIntroduction of carbon source will cause: Aerobic microbial consortia to use up all O2 Biofouling of borehole Drop in Dissolved O2- Redo

26、x Potential drop Anaerobic & facultative anaerobic consortia will take over & produce initially acid & fatty acid breakdown products Increase in acidity pH drops Reduction of Mn4+ (solid MnO2) Mn2+ (soluble) Solubilization of solid MnCO3 Mn2+ Reduction of ferric Fe3+ (solid haematite) fe

27、rrous Fe2+ (soluble) Production of ammonia Moving down the Redox LadderELEVATED LEVELS IN POLLUTED GROUNDWATER1 Overview2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels inpolluted groundwater10 Natural elevated lev

28、els in bedrock11 ConclusionsCASE STUDY A NE IRELAND ELEVATED LEVELS IN POLLUTED GROUNDWATER1 Overview2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels inpolluted groundwater10 Natural elevated levels in bedrock11 Co

29、nclusionsCASE STUDY AOLD POLLUTEDBOREHOLENEW UNPOLLUTEDBOREHOLENATURAL ELEVATED LEVELS IN GROUNDWATER1 Overview2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels inpolluted groundwater10 Natural elevated levels in be

30、drock11 ConclusionsCASE STUDY B COUNTY WEXFORD83m deep water abstraction borehole drilled to supply 19 residencesGrey shale bedrock becoming greyer with depthSoft rock encountered at 81-83m bgl followed by large water strikePump tested over 72 hours - sustained yield of 30.2m3/day 3 sets of samples

31、taken for laboratory analysis 24, 48 & 72 hoursElevated Mn levels - 1,140 to 670g/litre Drinking Water Limit - 50g/litre (10 times!)Normal Fe levels 60 to 250g/litre No ammonia, nitrates or bacteriaExcellent clarity, no odour or tasteFlow cell Redox 129mVNATURAL ELEVATED LEVELS IN GROUNDWATER1 O

32、verview2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels inpolluted groundwater10 Natural elevated levels in bedrock11 ConclusionsCASE STUDY BBallylane Formation - laminated green, green grey and grey slaty mudstone

33、s and green or pale grey siltstones, with occasional greywacke sandstones and andesitic volcanicsMaulin Formation dark phyllites, quartz rich siltstones which contain very small manganese-rich garnetsNATURAL ELEVATED LEVELS IN GROUNDWATER1 Overview2 Anthropogenic Input3 Air4 Soil & sediment5 Wat

34、er6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels inpolluted groundwater10 Natural elevated levels in bedrock11 ConclusionsCASE STUDY BMn2+- RichGroundwater?NATURAL ELEVATED LEVELS IN GROUNDWATER1 Overview2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Biocon

35、centration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels inpolluted groundwater10 Natural elevated levels in bedrock11 ConclusionsCASE STUDY BCASE STUDY B COUNTY WEXFORDWhere is the Mn coming from? Possibly went through Ballylane Formation into Maulin Formation at 81m bgl which is pr

36、oven to have Mn-rich garnets or coticules MnO2 or MnCO3 deposits within Ballylane Formation NATURAL ELEVATED LEVELS IN GROUNDWATER1 Overview2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels inpolluted groundwater10

37、Natural elevated levels in bedrock11 ConclusionsCASE STUDY BCASE STUDY B COUNTY WEXFORDWhat is the solution? Manganese Greensand is glauconite greensand (zeolite) impregnated with KMnO4 Capable of reducing iron, manganese and hydrogen sulfide from water through oxidation and filtration. Soluble iron

38、 and manganese are oxidized and precipitated by contact with higher oxides of manganese on the greensand granules.CONCLUSIONS1 Overview2 Anthropogenic Input3 Air4 Soil & sediment5 Water6 Bioconcentration7 Human Toxicity8 Influence of Redox & pH9 Elevated levels in polluted groundwater10 Natural elevated levels in bedrock11 ConclusionsSEDIMENTARY ROCK FORM