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IMPACTS OF HEAVY METALS FROM INDUSTRIAL WASTES ON SOIL FAUNA

IMPACTS OF HEAVY METALS FROM INDUSTRIAL WASTES ON SOIL FAUNA. BY: SOLANKE, ABIMBOLA AJIBOLA 129077030 DATE: 11/06/2013. OUTLINE. INTRODUCTION INDUSTRIAL WASTES AND COMPONENTS HEAVY METAL AS A TOXICANT SOIL FAUNA: BIODIVERSITY - Soil fauna and types - Importance of soil biodiversity

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IMPACTS OF HEAVY METALS FROM INDUSTRIAL WASTES ON SOIL FAUNA

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  1. IMPACTS OF HEAVY METALS FROM INDUSTRIAL WASTES ON SOIL FAUNA BY: SOLANKE, ABIMBOLA AJIBOLA 129077030 DATE: 11/06/2013

  2. OUTLINE • INTRODUCTION • INDUSTRIAL WASTES AND COMPONENTS • HEAVY METAL AS A TOXICANT • SOIL FAUNA: BIODIVERSITY - Soil fauna and types - Importance of soil biodiversity • IMPACTS OF HEAVY METALS ON SOIL FAUNA • CASE STUDY • RECOMMENDATIONS AND CONCLUSION

  3. INTRODUCTION • Industrial revolution in the 17th century led to a better standard of living, which in turn resulted in explosion of human population. • Although, Industrialization helped to generate employment, create different sources of income, and increase the overall well-being of this growing populace. • However, its activities and processes often leave a very harmful effect on the environment, which is usually ignored especially in developing countries (Scott, 1998).

  4. INTRODUCTION • Industrial wastes contain harmful substances like acids, heavy metals, which have hazardous effects on the physical environment, like the soil, hence affecting the soil organisms alike.

  5. INDUSTRIAL WASTES • Industrialization is the process of mechanical, physical and chemical transformation of raw materials into new forms so that they serve new ends and satisfy new requirements (Akhimienet al., 2012). • Industrial wastes are the by-products produced during industrial activities, such as that of factories, mills and mines. • These wastes, treated or not, are disposed into the environment.

  6. INDUSTRIAL WASTES (cont’d) • The final disposal of potentially toxic residues in the soil has become a practical and inexpensive alternative and can cause alterations in the arthropod community (Van, 2004). • They can be broadly categorized into: • Effluent: discharge of liquid wastes, usually into water bodies • Gaseous wastes

  7. FORMS OF INDUSTRIAL WASTES Plate 1a: discharge of industrial effluents into the environment Source: depositphotos.com. Plate 1b: smoke stack from chimneys Source: http://blog.airdye.com

  8. MAJOR CONSTITUENTS OF INDUSTRIAL WASTES • Oxides of Nitrogen (NOx) • Oxides of Sulphur (SOx) • Oxides of Carbon (CO and CO2) • Dust/particulates • Volatile organic compounds (VOCs) • Acid gases • Heavy metals • Organic micro-pollutants (e.g. polychlorinated biphenyl, polyhydrocarbons).

  9. INDUSTRIAL WASTES (cont’d) Plate 2: Industrial and Commercial Wastes Survey in UK in 2002/2003. Source: archive.defra.gov.uk

  10. HEAVY METAL AS A TOXICANT • Heavy metals are metallic elements with specific gravity higher than 5.00 and are toxic and poisonous even at low concentration (Duruibeet al., 2007; Lenntech, 2004). • Some, like Zinc and Iodine, are needed in trace quantities in the body. • They are persistent environmental contaminants, undergo speciation, and are bioavailable (Wuana and Okieimen, 2008).

  11. HEAVY METAL AS A TOXICANT (cont’d) • Although these elements are lacking in abundance they are not lacking in significance (Chen and Chen, 2001) • Toxicities of heavy metals can range from severe illness to death of both plants and animals (Galadima and Garba, 2012).

  12. Table 1: Examples of heavy metals and their specific gravity Source: Galadima and Garba, 2012.

  13. SOURCES OF HEAVY METALS • Natural sources: Heavy metals occur naturally in the soil environment, which are rarely toxic (Kabata-Pendias and Pendias, 2001). • Anthropogenic sources: Due to the disturbance and acceleration of nature’s slowly occurring geochemical cycle of metals by man.

  14. SOURCES OF HEAVY METALS (cont’d) • Anthropogenic emission into the atmosphere, for several heavy metals, is one-to-three orders of magnitude higher than natural fluxes (Sposito and Page, 1984). • Heavy metals in the soil from anthropogenic sources tend to be more mobile, hence bioavailable than pedogenicor lithogenicones (Kaasalainen and Yli-Halla, 2003).

  15. HEAVY METALS IN SOILS • Soils may become contaminated by the accumulation of heavy metals and metalloids through emissions from the • rapidly expanding industrial areas, • mine tailings, • disposal of high metal wastes, • leaded gasoline and paints, • land application of fertilizers, • animal manures, • sewage sludge, • pesticides, • wastewater irrigation, • coal combustion residues, • spillage of petrochemicals, and • atmospheric deposition (Khan et al., 2008)

  16. SOIL FAUNA • Soil biodiversity is comprised of the organisms that spend all or a portion of their life cycles within the soil or on its immediate surface (including surface litter and decaying logs). • Soil is the most abundant ecosystem on earth, however the vast majority of the organisms in the soil are microbes, a great number of which are yet to be described (Amber, 2008). • Roeschet al. (2007) suggested that there are over a million species per gram of soil, although a later study suggests a maximum of just over 50, 000 species per gram of soil.

  17. SOIL FAUNA (cont’d) • The level of abundance and diversity vary from soil to soil, depending on some factors such as: • Soil organic matter content, • Soil pH, • Soil texture, and • Soil management (Gardi and Jeffery, 2009). • In healthy soils, invertebrates are very abundant and thrive with minimal maintenance, adequate food supply and habitat requirements.

  18. TYPES OF SOIL FAUNA • There are three classes of soil fauna, on the basis of size (Gardi and Jeffery, 2009). These are: • Micro-fauna (1µm – 100µm) e.g. protozoa, nematodes • Meso-fauna (100µm – 2mm) e.g. mites, diptera (fly) larvae • Macro-fauna (2mm – 20cm) e.g. termites, earthworms

  19. SOIL FAUNA Plate 3: types of soil fauna according to size Source: Turbeet al., 2010.

  20. Plate 4: Meloidogyne incognita (root knot nematode)– a microfauna Source: wikipedia.

  21. Plate 5: Orchesellacinta(Springtail) - mesofauna Source: wikipedia

  22. Plate 6: Lumbricusterrestris – a Macrofauna Soure: www.soil-environment.blogspot.comsearchlabelheavy%20metals

  23. IMPORTANCE OF SOIL FAUNA • According to Turbeet al. (2010), importance of soil fauna can be summarized as follows: • Improvement of soil structure and fertility • Regulation of carbon flux and climate control • Regulation the of water cycle • Decontamination and bioremediation • Human health

  24. IMPORTANCE OF SOIL FAUNA (cont’d) Granular casts produced by earthworms that feed on dejections PLATE 7: An earthworm gallery filled with casts and a root SOURCE: Ruiz et al., 2008. Root using an earthworm gallery to penetrate into soil A part of the gallery is filled with earthworm excrement

  25. IMPACTS OF HEAVY METALS ON SOIL FAUNA • Pollution by heavy metals is a serious environmental concern, due to their non-biodegradability and tendency to accumulate in plants and animal tissues (Otitolojuet al., 2009). • The impacts of heavy metals on soil fauna: • Results in bioaccumulation. • Alters the abiotic environment such as temperature and humidity.

  26. DETRIMENTAL EFFECTS • Decrease in the diversity of species (Del Val et al., 1999; Syreket al., 2006; Beyremet al., 2007). • Reduction in microbial biomass activity • Introduction of invasive species (r-strategists)

  27. DETRIMENTAL EFFECTS CONT’D • Reduction in enzymes activities (Abdolkarimet al., 2009) • Heavy metals affect their ecological function (Smith et al., 2005). • Shortens the food chain (reduction in energy budget).

  28. DETRIMENTAL EFFECTS CONT’D • Increase in abundance of species (invasive species). • There was abundance of Protura, Diplura and Collembola with increase in the pollution by metals (Miglioriniet al. , 2004).

  29. CASE STUDYDynamics of soil nematodes and earthworms in urban vegetable irrigated with wastewater in the Nairobi River-Basin, Kenya, by Karanjaet al., 2010. • The effects of heavy metals lead (Pb), Cadmium (Cd) and Chromium (Cr) on nematode communities and earthworm density and biomass were studied in the wastewater irrigated farms of the Nairobi River Basin (Kibera and Maili-Saba farms). • The soil samples and effluent were tested for Pb, Cd, and Cr

  30. CASE STUDY (cont’d) • Monolith sampling for earthworms was done using the procedures described by Moreira et al. (2008) • Nematodes were examined using modified Baermann’s procedure described by Hooper et al. (2005)

  31. CASE STUDY (cont’d) • TABLE 2: Heavy metal accumulation in soils in the Kiberaand Mali-Saba farms Source: Karanjaet al., 2010.MPL*: Maximum Permissible Limits (WHO, 2006).

  32. CASE STUDY (cont’d) • Table 3: Plant feeding nematode genera and trophic groups associated with wastewater in Kibera and Maili Saba * Significant difference between pairs at P<0.05 Source: Karanjaet al., 2010.

  33. CASE STUDY (cont’d) Table 4: Bacteria feeding nematode genera and trophic groups associated with wastewater in Kibera and Maili Saba. * Significant difference between pairs at P<0.05 Source: Karanjaet al., 2010.

  34. CASE STUDY (cont’d) Figure 1: Earthworm abundance and biomass in wastewater treated plots Source: Karanjaet al., 2010.

  35. CASE STUDY (cont’d): DISCUSSION • High heavy metal concentration as well as organic matter were negatively correlated with the plant feeding nematodes (Table 3). • Ekshmitt and Korthals (2006) obtained similar result. • Bacteria feeding nematodes were predominant in the gardens treated with heavy metals (57% of all nematodes found) (Table 4).

  36. CASE STUDY (cont’d): DISCUSSION • An average density of 198 m-2 of earthworms and a biomass of 68 gm-2 were found in Kibera; • An average density of 102 m-2 of earthworms and a biomass of 33 gm-2 were found in Maili-Saba (Figure 1). • The earthworms isolated from both sites were epigeic with the metal content in Maili-Sapa suppressing their population

  37. CASE STUDY (cont’d): CONCLUSION • High heavy metal concentration affects the population of plant feeding nematodes, but enhances the population of bacteria feeding nematodes. • Amongst the heavy metals under this investigation, Cd is known to be the most toxic (Vandescateele, 2004) while Cr and Pb may not significantly affect earthworm activities and growth according to Kumar et al., (2008).

  38. RECOMMENDATION • Pretreatment of industrial discharges from sewage using efficient Effluent Treatment Plants (ETP). • Enforcement of existing environmental guidelines. • Frequent review of maximum permissible limits of heavy metals. • Regular inspection of industrial wastes, treated or not, that arebeing discharged into the environment. • Remediation of impacted soils/environment.

  39. CONCLUSION • Soil fauna are very significant in the proper functioning of an ecosystem. • Man is the greatest threat to their existence, and we need them more than they need us. • Thus, it is imperative that we stop/reduce heavy metal pollution to ensure their survival, our survival.

  40. THANK YOU FOR LISTENING

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