1.1. Major sources of water contamination

There are many sources of drinking water and the main sources are ground water, lakes, canals, reservoirs, rain water, fog water and sea water. These sources are contaminated in different ways and broadly the source of contamination can be divided in to two categories:

• Direct sources or point sources

fresh water (Figure 1a) and of that 3% about 68.7% of freshwater is locked up in icecaps and glaciers (Figure 1b), and it is quite a surprising fact that almost all the remaining fresh water is below the ground. Of all the freshwater on the surface of earth only 0.3% is contained in fresh

62 Emerging Pollutants - Some Strategies for the Quality Preservation of Our Environment

As the population is increasing day by day the water availability per capita is decreasing. So the challenge of limited amount of freshwater and its decreasing per capita availability is an issue of concern but another major challenge is water pollution that has not only environmental impact but also have a major effect on human health. As per the statistics 783 million people do not have access to clean and safe water worldwide [2]. Around 319 million people in Sub-Saharan Africa are without the access to improved reliable drinking water sources. One in nine people worldwide do not have access to safe and clean drinking water. 443 million school days are lost each year due to water-related diseases [3]. In developing countries, as much as 80% of illnesses are linked to poor water and sanitation conditions [4]. 2.6 billion people in the world lack adequate sanitation and which contributes to about 10% of the global disease burden [5]. Half of the

world's hospitals beds are filled with people suffering from a water-related disease [6].

There are various type of illnesses due to water and are summarized in Table 1.

Figure 1. (a) Water distribution on the earth and (b) freshwater distribution on the earth.

Water based Organism developed in water and then become

parasite

Table 1. Various types of illness due to water.

Water-related insect

vector

Water borne Human or animal waste Cholera, typhoid, and

Type of diseases Source Example References

Mosquitoes breed in water Malaria and dengue [9]

Water washed Lack of clean water for washing Skin and eye infections [8]

dysentery,

Schistosomiasis [9]

[7]

lakes, and rivers [1].

• Indirect sources or non-point sources

Direct sources basically include effluent from industries, treatment plants, refineries, factories, etc. However, indirect sources or non-point sources include the water contamination entering to the water body through a number of processes, e.g., while putting the fertilizers and pesticides to the agricultural field, the elements presents in the chemical percolates down to the groundwater and ultimately pollute the water.

### 1.2. Different types of water contaminants

There are various types of water contaminants, however in the following subsections organic contaminants, inorganic contaminants and pathogens are briefly discussed.

### 1.2.1. Organic contaminants

Organic contaminants present in drinking water create severe problem on human health. Pollution by organic chemicals in water bodies occurs by various mechanisms. Industrial waste containing various organic chemical contaminants pollutes the water bodies. Volatile organic compounds (VOCs), pesticides, phenolic compounds, phthalates, and nitrogen-containing compounds, are often detected in polluted water [11]. Many of these compounds have been found to be carcinogenic, even in very low concentrations. WHO Guidelines for drinking water quality, levels are set for 28 organic constituents (i.e., microcystin-LR, chlorinated alkanes, chlorinated benzenes and miscellaneous), 33 pesticides, and 9 disinfectant by-products, due to their health effects on humans [12]. It is noteworthy to mention that, occurrence of pharmaceutical and personal care products and perfluoroalkyl acids in aquatic environment has been recognized as emerging issue in environmental chemistry [13].

chemical disinfection), and desalination (reverse osmosis, distillation). The various techniques

Study on Magnetic Materials for Removal of Water Pollutants

http://dx.doi.org/10.5772/intechopen.75700

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There are specific advantages and disadvantages for a particular process. The nanotech based processes are promising option in current water treatment processes because of their target specificity, ease of separation, high adsorption per unit area, as well as less maintenance.

There has been increased interest in using magnetic materials in water treatment which are basically composed of magnetic core of iron oxides organic compounds, carbon materials, etc. Recently, nanomaterials in different shapes, morphologies, forms, e.g., metal-containing nanoparticles, carbonaceous nanomaterials, zeolites, dendrimers, carbon nanotubes, nanofibers have been used for water purification [20]. However, the difficulty arises in using these materials is the separation of solid materials from liquid and which is more difficult as the particle size decreases in nanoscale. On the other hand, the using of magnetic, particularly the magnetic nanoparticles (MNPs) materials have the advantage of

However solid/liquid (S/L) separation is more difficult as the particle size decreases. On the other side, in case of magnetic sorbents based on Fe oxides, the magnetic filtration may be applied for S/L separation. Furthermore, the removal of particles from solution with the use of magnetic fields is more selective and efficient (and often much faster) than centrifugation or filtration (Yauvuz et al.) [21]. Here are the advantages of using MNPs adsorbent for water

• Solid/liquid separation through magnetic filtration is selective, faster than centrifugation

magnetic filtration in separation of solid from liquid and are more efficient [21].

in water treatment can categorized into following six classes [19]:

• Adsorption

• Biotechnology

• Catalytic processes

• Membrane processes

treatment processes:

• Reusability

and filtration techniques

• Greater biocompatibility

• Magnetic separation

• Ionizing radiation processes

• Magnetically assisted processes.

3. Magnetic materials for water treatment

• Small size and thus high surface to volume ratio

### 1.2.2. Inorganic contaminants

Inorganic contaminants include metals, salts and other compounds that do not contain carbon. Many of them are naturally occurring and should be considered as an integral part of those waters, e.g., calcium carbonate and bicarbonate in hard water. The metal ions such as Hg(II), Pb(II), Cr(III), Cr(VI), Ni(II), Co(II), Cu(II), Cd(II), Ag(I), As(V) and As(III) are toxic from eco toxicological point of view. Besides, the pollution by the radioactive elements is of major concern looking into their long-term hazardous impacts.

#### 1.2.3. Pathogens

Pathogens such as bacteria, viruses and parasites may be present in very low concentration in drinking water; but cause many infectious diseases and are considered as one of the major risk factors with drinking water safety [14]. The pathogenic microorganisms enter in to water body through sewage discharge as a major source or through the wastewater from industries like slaughterhouses. Water-borne pathogens have been the causes of many disease outbreaks such as diarrhea, cholera, gastro-intestinal illness [15]. The recurrence of water-borne pathogens is due to a number of reasons like heavy water contamination, population explosion, change in potable water treatment methods, globalization of commerce and travel. It has been made possible to detect pathogen based water contamination to a large extent owing to the improved methods for detection and source tracking [16, 17]. The most serious health risk is related with ingestion of water which is contaminated with fecal matter and the discharge of wastewater into various ambient water bodies is what contributes to the multiplication of numbers of such pathogens (bacteria, viruses, protozoa and helminthes) [18].
