GEMAS – soil, geology and health implications “All substances are poisons; there is none which is not a poison. The right dose differentiates a poison and a remedy” Paracelsus (1493- Anna Ladenberger (Source: http://gnosticwarrior.com/wp-content/uploads/2013/07/paracels
GEMAS – soil, geology and health implications. Anna Ladenberger. “All substances are poisons; there is none which is not a poison. The right dose differentiates a poison and a remedy” Paracelsus (1493-1541). (Source: http://gnosticwarrior.com/wp-content/uploads/2013/07/paracelsus.jpg). - PowerPoint PPT Presentation
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
GEMAS – soil, geology and health implications
“All substances are poisons; there is none which is not a poison. The right dose differentiates a poison and a remedy”
Sixteen trace elements are established as being essential for good health
MICRONUTRIENTS (B, Cu, Co, Cr, F, I, Li, Mn, Mo, Ni, Se, V,
Zn)
NON-ESSENTIAL (As, Be, Cd, Pb, Sb, Sn, Ti)
PATTERNS OF INFLUENCE OF THE ELEMENTSassimilation increase
MACRONUTRIENTS (Ca, Fe, K, Mg, P, S)
deficit good no difference
deficit good toxic lethal
tolerable toxic lethal
(From Siegel, 2002)
Element (bio)availability
Soil varies widely in concentrations of macro- and micro- (trace) elements, even without human induced environmental
contamination and agriculture.
Soil (or sediment) horizons can have high concentrations of:• Ions released from weathering; • Ions introduced as fertilisers (P, K, S);• Environmental pollutants (heavy metals, etc.).
High concentrations do not mean that the element is ’available’!
250 mg/kg
60 mg/kg
10 mg/kg
(From Reimann et al., 2014, Fig. 11.63.4, p.463)
(From Reimann et al., 2014, Fig. 11.63.2, p.462)
Zinc (Zn) is an essential micronutrient Zinc deficiency is widespread in soil Nearly 50% of the soil on which cereals
are grown have levels of available Zn low enough to cause Zn deficiency
The median in Ap soil is 45 mg/kg with a typical range from 10 to 200 mg/kg.
(Alloway, 2008)
Zinc
(Map of Zinc deficiency in World crops From Alloway, 2008, Fig. 6.5, p.109)
Zinc • essential for over 300 enzymes• antioxidant
Symptoms of Zn deficiency include: poor plant growth loss of appetite (anorexia) decreased immune function
Zinc
(From Reimann et al., 2014, Fig. 11.63.5, p.465)(From Mann et al., 2014, Fig. 13.17, p.219)
Once identified, zinc-deficient soil can be easilytreated with fertilisers containing zinc to provide
(From Ottesen et al., 2013, Fig. 8, p.10, based on data from Wheeler & Ummel, 2008)
(Source: http://whyfiles.org/201mercury/)
mobile under oxidising alkaline conditions (pH>7.5)binds to organic matterimmobile under reducing conditionsimmobile under low pH – forms complexes with Fe oxidesdietary source of Se: mushroom, garlic, sea food, liver and kidneys, fish, flour, whole-
grain products
Essential element (enzymes, antioxidant)
Anticancer activity Narrow range between
dietary deficiency (<40 µg per day) and toxicity (>400 µg per day)
Selenium
0.4 mg/kg
0.6 mg/kg
(From Reimann et al., 2014, Fig. 11.50.4, p.389)
High in Se: black shale, phosphatic rocks, sulphides, coal, humus rich soil in coastal regions, volcanic ashes (tuffs), fine-grained sediments Anthropogenic Se: burning fossil fuels, smelting, sewage sludge, manure, pesticide, phosphate fertilisers, photocopier, anti-fungal pharmaceuticals, lubricating oils, ink
Se toxicity in drinking water (Reggio)
Selenosis in Limerick (cattle, horses)
Selenium
(From Reimann et al., 2014, Fig. 11.50.5, p.391) (From Reimann et al., 2014, map on DVD)
Se deficiency: common in Sweden, Finland, Denmark heart disease (Keshan disease) bone and joint disease, rheumatics poor growth and development weak immune respond
Se toxicity:Se excess causes hair loss, nerve and
liver damage, caries, garlic smell of breath, blue staining of nails;
Population can adapt to high selenium intake without showing major clinical symptoms.