Soil quality and links to health

Transcription

1 Soil quality and links to health Fiona Fordyce British Geological Survey Edinburgh

2 Chemical Quality of the Environment Naturally Occurring Elements: approximately 26 are essential to plant/animal/human health in small doses, but harmful in excess * * * H Li Na K Rb Cs # Fr Essential to most organisms (may be toxic in excess) * Generally toxic to most organisms * * * * * Be Biological function suspected B C N O F Ne # Radioactive * Mg * Al * Si * P * S * Cl Ar * Ca Sc Ti V Cr * Mn * Fe * Co Ni * Cu * Zn Ga Ge * As Se * * * * Br Kr Sr Y Zr Nb * Mo # Tc Ru Rh Pd Ag * Cd In * Sn * Sb Te * I Xe Ba La Hf Ta W Re Os Ir Pt Au * Hg * Tl * Pb Bi # Po # At # Rn # Ra # Ac La Ce Pr Nd # Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lw (All# ) He Of concern also, man-made potentially harmful substances - organic pollutants e.g. PAHs and PCBs

3 Land Contamination Guidelines Human Health: UK Environment Agency (EA) Contaminated Land Exposure Assessment (CLEA) generic Soil Guideline Values (SGVs). Over the last 5 years CLEA SGVs being revised. New DEFRA Category 4 soil screening levels (C4SL) have been developed for England and Wales Scotland currently re-examining its guidelines Exceedence = further investigation required, not that land is contaminated Significant uncertainty in soil exposure assessments (EA 2009) Soil Guideline As mg kg -1 Cd mg kg -1 Residential Allotment Commercial Open Space Residential Allotment Commercial Open Space C4SL (2014) 37/ /168 26/ /880 CLEA (2009) CLEA (2002) (ph 6) 1400 Cr (CrVI) mg kg -1 Ni mg kg -1 Residential Allotment Commercial Open Space Residential Allotment Commercial Open Space C4SL (2014) (21/21) (170) (49) (23/250) CLEA (2009) CLEA (2002) Pb mg kg -1 Se mg kg -1 Residential Allotment Commercial Open Space Residential Allotment Commercial Open Space C4SL (2014) 200/ /1300 CLEA (2009) CLEA (2002)

4 Uncertainty in Exposure Linkages SOURCE PATHWAY RECEPTOR Substances in Air, soil, water, Humans air, soil, water etc food-chain etc Exposure indicators exposure e.g. blood, urine etc Humans Health outcomes? Very little info on human exposure biomarkers Even if we get that, just because an exposure biomarker identified, does not equate to a health outcome To improve exposure assessments BGS international leaders developing: Bioaccessibility Tests how much of a substance is taken up into the body Lab-based tests that mimic stomach conditions for ingestion, lung conditions for inhalation and dermal contact for soils and dusts Have been validated against animal models for several potentially harmful substances Traditionally developed for metals Now being developed for organic pollutants also

5 Soil Cr Geology/Urban Influences From: In Press Fordyce F M, Everett P A, Bearcock J M and Lister T R. Soil metal quality and anthropogenic impacts in the Clyde Basin, Scotland, UK. Controls: higher over geology (volcanics), Mn-Fe oxides, urban pollution (metal processing) Lower in organic-rich soils Highest concentrations ironstone pits and Cr-ore processing works Cr waste

6 Glasgow Soil Cr - Bioaccessibility Joint PhD Edinburgh University BGS URS (EDEN) Student: Andrew Broadway. Supervisors: John Farmer, Bryne Ngwenya, Mark Cave, Fiona Fordyce, Richard Bewley Largest Cr works in world in Rutherglen Glasgow 1968 Cr speciation in soils also assessed Cr 6+ (industrial form) is more toxic than Cr 3+ (natural form) Bioaccessibility of Cr in 27 G-BASE soils including known Cr-waste sites in Glasgow BGS Unified Bioaccessibility Method (UBM) to determine human Cr exposure from soil ingestion Simulated lung experiment to determine inhalation exposure UBM Cr Method from Broadway et al., 2006 Appreciable Cr 6+ was found in known Cr-waste soils only Cr 6+ was more bioaccessible than Cr 3+ in the soils During ingestion Cr 6+ was reduced to Cr 3+ in presence of soil organic matter - less risk to human health From : Broadway A, Cave, M R, Wragg J, Fordyce F M, Bewley R J F, Graham M C, Ngwenya B T and Farmer J G Determination of the bioaccessibility of chromium in Glasgow soil and the implications for human health risk assessment. Science of the Total Environment, 409 (2), Via inhalation bioaccessible Cr 6+ was present in two Crwaste samples (<10 µm material) possible risk

7 Glasgow Land Quality- Health/Deprivation Joint MSc BGS Glasgow University Sponsored by NHS. Student: Steven Morrison. Supervisors: Marian Scott, Fiona Fordyce Glasgow Overall Metal Score No data a This study - spatial statistics - health (respiratory case incidence rates) versus G-BASE soil quality, deprivation and air quality (PM 10 and NO 2 ) indicators Comparisons between 279 intermediate geography zone area averages. Significant association between respiratory case rates and soil Ni (p=0.0056) and soil metal score (p=0.0367) May just reflect lower soil metal content and lower respiratory disease in rural areas versus the urban areas Cannot say there is a causal link but results are interesting given Ni is a respiratory irritant Glasgow Median deprivation decile 1 & 2 3 & 4 5 & 6 7 & 8 9 & 10 No data b Cannot discount that metal-rich airborne dusts contribute to respiratory cases : Growing evidence that re-suspension of soil accounts for 45 75% of metals in PM 10 air particulates (Young et al. 2002; Cave and Chenery 2010; Laidlaw et al. 2012) and is significant component of PM 2.5 (Celo and Dabek-Zlotorzynska 2011) Showed for the first time in a UK city: poor soil quality associated with deprivation (-0.213; p-value<0.05) Geoscience BGS, NERC; Topography Crown Copyright. All rights reserved. BGS / SIMD Scottish Index of Multiple Deprivation. a) Soil Metal Score (geomean of 5 metals ) b) Deprivation Index Inequality of potential exposure - soil quality should be taken into account in environmental justice indices in future From: Morrison S, Fordyce F M and Scott E M An initial assessment of spatial relationships between respiratory cases, soil metal content, air quality and deprivation indicators in Glasgow, Scotland, UK: relevance to the environmental justice agenda. Environmental Geochemistry and Health, Volume 36, Issue 2,

8 Improve Risk Assessments Several studies shown evidence of spatial association between health/deprivation indicators and brownfield/derelict land Evidence from other countries of links between poor soil quality and health In UK context, need to understand mechanisms of likely exposure/impacts Can attempt to mimic/model human soil exposure (e.g. bioaccessibility tests) BUT Very little human biomonitoring data to assess whether soil exposure has the expected uptake into the human body Very little data on health markers and outcomes as a result of typical or non-acute soil exposure BGS involved in recent study shows spatial association between higher skin cancer (basal cell carcinoma) and soil arsenic in urban populations based on The Health Improvement Network database (THIN) In Press: Musah A, Leonardi-Bee J, Hextall FB, Ander EL, Cave MR and Gibson JE. Arsenic in UK topsoil and risk of Basal Cell Carcinoma: A population based cohort study. BGS involved in As drinking water SW England with PHE BGS working with Glasgow Uni soils and health Ethical approval/medical by-in, barriers to this type of research Information required to improve land quality policy and aid urban regeneration Trade-offs between provision of safe environments versus utilisation of green space for health living and public perception of risk and environmental quality