environment pollution and its chemistry

environment ions

1. Natural water is a dynamic chemical system containing in its composition a complex group of gases, mineral and organic substances in the form of true solutions, and suspended and colloidal matters as well The variety and complexity of natural water composition is defined not only by the occurrence of a large number of chemical elements in it, but also by the difference of forms and the values and presence of each of them. Almost all known chemical elements occur in natural water, proving academician’s V.I. Vernadsky statement that in each water drop the composition of the macrocosmos is reflected as in a microcosm. About 90 stable chemical elements contained in the Earth’s crust are found in natural water Chemical Composition of Natural Waters. The chemical composition of natural water (rivers, lakes, seas, wetlands and other) is usually classified under three headings: Main ions 2. Dissolved gases 3. Biogeneous substances Main ions Mineral substances contained in natural waters in the dissolved state (in the form of ions, complex ions, undissociated compounds and colloids) are conventionally subdivided into macrocomponents and microcomponents . The macrocomponents comprise the so-called main ions that determine water chemical type and account for the bulk of natural water mineral content (up to 95% for fresh water and up 99% for highly mineralized waters). The microcomponents comprise substances occurring only under certain conditions and in very small concentrations ( μg⋅l -1 and < 1 mg⋅l -1). An intermediate position is occupied by ions of hydrogen, compounds of nitrogen, phosphorus, and silicon dissolved in water Ions concentration in natural water

2. The concentrations of all minerals is related to two main factors— the abundance of chemical elements in the Earth’s crust and the solubility of their compounds . The main anions contained in natural water are Cl - , SO4 2- , HCO 3 - , and CO3 2- and the main cations are Ca 2+ , Na + , Mg2 + and K + Chloride ions (Cl - ) have a large migratory ability in connection with the very high solubility of chloride salts of sodium, magnesium and calcium. Their presence in water is naturally associated with the processes of leaching from minerals (e.g. gallite , sylvite, carnallite, bischofite), from rocks (e.g. nephelines), and from saline deposits. It is also present in atmospheric precipitation, and today it is particularly associated with industrial and municipal wastes. Sulfate ions (SO4 2- ) are contained in all surface waters, and their content is limited by the presence of calcium ions together with which they form a slightly soluble CaSO 4 . The main source of sulfate in water is various sedimentary rocks which include gypsum and anhydride. Water enrichment by sulfates takes place both by the process of oxidation of sulfide, which is abundant in the Earth’s crust, and oxidation of hydrogen sulfide which is created during volcanic eruption and is present in atmospheric precipitation. Hydrocarbonate and carbonate ions (HCO 3 - and CO3 2- ) occur in natural waters in dynamic equilibrium with carbonic acid in certain quantitative proportions and form a carbonate system of chemical equilibrium connected with the pH of water. When the pH of a water system is 7 to 8.5 the predominant ion is hydrocarbonate. When pH is less than 5, the content of hydrocarbonate ions is close to zero. Carbonate ions dominate when pH>8. The sources of HCO3 - and CO3 2- are various carbonate rocks (limestones, dolomites, magnesites), from which dissolution takes place with the participation of carbon dioxide.

3. Ions of sodium (Na + ). The migratory ability of sodium as an element is rather high, as all its salts have high solubility. In waters with low mineralization Na + is third in concentration.. A high proportion of the sodium ions is balanced by chlorine ions, forming a stable mobile combination that migrates with high velocity in a solution. The sources of Na+ in waters are deposits of various salts (rock-salt), weathering products of limestone rocks, and its displacement from the absorbed complex of rocks and soils by calcium and magnesium. Ions of potassium (K + ). Potassium, in terms of the magnitude of its content in the Earth’s crust and the solubility of its compounds, is very similar to sodium. However, it occurs in lower concentrations in surface waters as it has weak migratory ability. This is due to its active participation in biological processes, e.g. absorption by living plants and micro-organisms. Ions calcium. (Ca 2+ ). The basic sources of calcium are carbonate rocks (limestones, dolomites) that are dissolved by carbonic acid contained in water. When the availability of carbon dioxide (with which it in a balance), is low, however, the reaction begins to proceed in a reverse direction, accompanied by precipitation of CaCO 3 . Another source of Ca 2+ in natural waters is gypsum, is common in sedimentary rocks. Calcium ions dominate in the cation composition of low-mineralized waters. Ions of magnesium (Mg 2+ ). Magnesium is less abundant than calcium in the Earth’s crust. It enters surface water as a result of the processes of chemical weathering and dissolution of dolomites, marls, and other rocks. Magnesium ions occur in all natural waters, but very seldom dominate. Its concentration in river waters ranges from one to tens of mg. The weaker biological activity of magnesium, as compared with calcium, and also the higher solubility of magnesium sulfate and hydrocarbonate as compared the equivalent compounds of calcium, favor increase of Mg2+ concentration in water. With higher water mineralization, the ratio between calcium and magnesium begins to change towards predominance of the latter

4. In the composition of natural waters hydrogen ions H+ take an especially important place, though their absolute content as compared with other ions is very low. Ions of hydrogen are always present in water as they arise during electrolytic dissociation of water itself: H2O⇔H+ +OH- . Concentration of hydrogen ions in water solution is determined by the so-called ionic product of water Kw=[H+ ][OH- ]. It follows that the product of concentrations (in gram molecules) of hydrogen ions and hydroxyl at a temperature of 22 o C, is always equal to a constant value, Kw = 1⋅10-4. Concentrations of hydrogen and hydroxyl ions are very small, which is why it is customary to present it in the form of their logarithm with the reversed sign of pH = -l g[H+ ]; pOH = -l g[OH- ]. Dissolved Gases The composition of gases connected with the exchange processes between water and atmosphere depends mainly on their content in the atmosphere. Processes that take place in water bodies, including biochemical ones, require the presence of oxygen (which is formed during photosynthesis), carbon dioxide, methane, and, to a lesser extent, hydrogen sulfide , ammonia, heavy hydrocarbons, and nitrogen. Volcanic processes and degassing of the Earth’s mantle supply oxides and dioxides of carbon, methane, ammonia, hydrogen sulfide , hydrogen, hydrogen chloride, sulfurous gas and others into natural waters. Some other gases can appear and dissolve in water as a result of ultra-violet irradiation (ozone), thunderstorm discharges (nitric oxide), and anthropogenic pollution ( sulfurous gas, vapors of iodine, ammonia, carbonic oxide, etc.). Biogenous Substances . Substances that are connected by their origin with the vital activity of aquatic organisms, which determine the possibility for their existence in a water bodies, are called biogenous . These include compounds of silicon, nitrogen, phosphorus and iron.

5. Pure drinking water (potable water) is absolutely essential for our survival. More than 1 billion people in the world have limited access to safe drinking water. Furthermore, nearly 2.6 billion people have issues relating to poor sanitation that results in inferior water quality. Over 1 million people die every year from sicknesses communicated through use of unsafe water. Drinking-water pollution is caused by the careless disposal of pharmaceuticals, fertilizers, pesticides, and a large variety of other chemicals. This results in contamination of our drinking-water sources with heavy metals, radionuclides, pesticides, plastics, organic nutrients, inorganic pollutants, pharmaceuticals, etc. Polluted drinking water is a major cause for a variety of different diseases in human beings. To solve these critical issues, it is necessary to purify contaminated water. Potable water, also called drinking or tap water, is used for sanitary purposes such as drinking fountains, showers, toilets, hand-wash basins, cooking, etc. If the water supply to the facility is from a public system such as city water, the Environmental Protection Agency (EPA) Standards.  Table .1 is a highlight of a typical water supply standard . Potable water and its chemicals composition

6. Item Specification Appearance 1 Turbidity Unit Chloride 250 ppm Fluoride 1.4 to 2.4 mg/L Sulfate 250 ppm Lead 0.05 mg/L Fecal Coliforms 1/100 ml (Proposed: 0/100 ml) Pyrogens Not Specified Other Microbes Not Specified Total Dissolved Solids 500 mg/L Arsenic 0.05 mg/L Barium 1.0 mg/L Cadmium 0.010 mg/L Chromium Hexavalent 0.05 mg/L Chloroform 0.7 mg/L Cyanide 0.2 mg/L Mercury 0.002 mg/L Nitrate 10 mg/L Selenium 0.01 mg/L Silver 0.05 mg/L Pesticides  Chlorodane 0.003 mg/L  Endrin 0.0002 mg/L  Heptachlor 0.0001 mg/L  Heptachlor Epoxide 0.0001 mg/L  Lindane 0.004 mg/L  Methoxychlor 0.1 mg/L  Toxaphene 0.005 mg/L  2, 4-D 0.1 mg/L  2, 4, 5-TP (Silvex) 0.01 mg/L  Specific Resistance 10,000 ohms/cm (typically)  pH 6.5–8.5 Minimum potable water standard

7. Pollution “ Pollution is the introduction of substances (or energy) that cause adverse changes in the environment and living entities Water pollution and its causes Water pollution  is said to occur when toxic pollutants and particulate matter are introduced into water bodies such as lakes, rivers and seas. These contaminants are generally introduced by human activities like improper  sewage treatment  and oil spills. However, even natural processes such as  eutrophication  can cause water pollution. Other significant causes of water pollution include: Dumping solid wastes in water bodies Disposing untreated industrial sewage into water bodies Human and animal wastes Agricultural runoff containing pesticides and fertilisers The effects of water pollution are very pronounced in  our environment .  Furthermore, toxic chemicals can bioaccumulate in living beings, and these chemicals can travel their way up the food chain, ultimately reaching humans.

8. Sources Of Water Pollution The key causatives of water pollution in India are: Urbanization. Deforestation. Industrial effluents. Use of Detergents and Fertilizers. Agricultural run-offs- Use of insecticides and pesticides . One of the primary   causes of water pollution   is the contamination of water bodies by toxic chemicals. As seen in the example mentioned above, the dumped plastic bottles, tins, water cans and other wastes pollute the water bodies. These result in water pollution, which harms not just humans, but the whole ecosystem. Toxins drained from these pollutants, travel up to the food chain and eventually affect humans. In most cases, the outcome is destructive to only local population and species, but it can have an impact on a global scale too. Nearly 6 billion kilograms of garbage is dumped every year in the oceans. Apart from industrial effluents and untreated sewage, other forms of unwanted materials are dumped into various water bodies. These can range from nuclear waste to oil spills – the latter of which can render vast areas uninhabitable.

9. Effects Of Water Pollution The effect of water pollution depends upon the type of pollutants and its concentration. Also, the location of water bodies is an important factor to determine the levels of pollution. Water bodies in the vicinity of urban areas are extremely polluted. This is the result of dumping garbage and toxic chemicals by industrial and commercial establishments. Water pollution drastically affects aquatic life. It affects their metabolism, behaviour , causes illness and eventual death. Dioxin is a chemical that causes a lot of problems from reproduction to uncontrolled cell growth or cancer. This chemical is bioaccumulated in fish, chicken and meat. Chemicals such as this travel up the food chain before entering the human body. The effect of water pollution can have a huge impact on the food chain. It disrupts the food-chain. Cadmium and lead are some toxic substances, these pollutants upon entering the food chain through animals (fish when consumed by animals, humans) can continue to disrupt at higher levels. Humans are affected by pollution and can contract diseases such as hepatitis through faecal matter in water sources. Poor drinking water treatment and unfit water can always cause an outbreak of  infectious diseases  such as cholera, etc. The ecosystem can be critically affected, modified and destructured because of water pollution .

10. In 1932, a factory in Minamata City, Japan began dumping its industrial effluent – Methylmercury, into the surrounding bay and the sea. Methylmercury is incredibly toxic to humans and animals alike, causing a wide range of neurological disorders.

11. Control Measures of Water Pollution Water pollution, to a larger extent, can be controlled by a variety of methods. Rather than releasing sewage waste into water bodies, it is better to treat them before discharge. Practising this can reduce the initial toxicity and the remaining substances can be degraded and rendered harmless by the water body itself. If the secondary treatment of water has been carried out, then this can be reused in sanitary systems and agricultural fields. A very special plant, the Water Hyacinth can absorb dissolved toxic chemicals such as cadmium and other such elements. Establishing these in regions prone to such kinds of pollutants will reduce the adverse effects to a large extent. Some chemical methods that help in the control of water pollution are precipitation, the ion exchange process,  reverse   osmosis , and coagulation. As an individual, reusing, reducing, and recycling wherever possible will advance a long way in overcoming the effects of water pollution .

12. Purification of water What is sewage treatment? Wastewater treatment or sewage treatment generally refers to the process of cleaning or removing of all pollutants, treating wastewater and making it safe and suitable for drinking before releasing into the environment. What are the main steps in sewage treatment? There are four main stages of the wastewater treatment process, namely: Stage 1: Screening Stage 2: Primary treatment Stage 3: Secondary treatment Stage 4: Final treatment

13. Water purification  means the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water. The goal is to produce water that is fit for specific purposes. Most water is purified and disinfected for human consumption ( drinking water ), but water purification may also be carried out for a variety of other purposes, including medical, pharmacological, chemical, and industrial applications. The history of water purification includes a wide variety of methods. The methods used include physical processes such as  filtration ,  sedimentation , and  distillation ; biological processes such as  slow sand filters  or  biologically active carbon ; chemical processes such as  flocculation  and  chlorination ; and the use of electromagnetic radiation such as  ultraviolet light . Water purification may reduce the concentration of particulate matter including  suspended   particles ,  parasites ,  bacteria ,  algae ,  viruses , and  fungi  as well as reduce the concentration of a range of dissolved and particulate matter. Water purification

14. Disinfection of water Disinfection is the final stage in drinking water treatment before its distribution. Disinfection is used to remove pathogenic micro-organisms from the water. However, it should be noted that disinfection is not the same as sterilisation ( sterilisation = destruction of  all  germs present in a medium) and therefore a few common germs may remain in the water following disinfection B actericidal effect – remanent effect The disinfection of water comprises two important steps that refer to two different properties of a given disinfectant: bactericidal effect  : this is the disinfectant’s capacity for destroying microorganisms during a specific stage of the treatment; remanent effect :  this is the disinfectant’s capacity to persist in the water in the mains distribution network and its ability to maintain the water’s biological quality at the consumer’s tap. Disinfection provides both bacteriostatic protection against bacterial regrowth as well as a bactericidal effect against low level and occasional pollution affecting the mains network; at the same time, disinfection blocks the development of micro-invertebrates which could have passed through the plant in resistant (endospores) or reproductive forms (cysts).

15. Groundwater and its supply in india Groundwater  is the  water  present beneath  Earth 's surface in rock and  soil pore spaces  and in the  fractures  of  rock formations . A unit of rock or an unconsolidated deposit is called an  aquifer  when it can yield a usable quantity of water. The depth at which  soil  pore spaces or fractures and voids in rock become completely saturated with water is called the  water table . Groundwater is  recharged  from the surface; it may discharge from the surface naturally at  springs  and  seeps , and can form  oases  or  wetlands . Groundwater is also often withdrawn for  agricultural ,  municipal , and  industrial  use by constructing and operating extraction  wells . The study of the distribution and movement of groundwater is  hydrogeology , also called groundwater  hydrology . An  aquifer  is a layer of porous substrate that contains and transmits groundwater. When water can flow directly between the surface and the saturated zone of an aquifer, the aquifer is unconfined. The deeper parts of unconfined aquifers are usually more saturated since gravity causes water to flow downward.

16. India In India, 65% of the  irrigation is from groundwater [  and about 90% of extracted groundwater is used for irrigation. The groundwater regulation is controlled and maintained by the central government and four organizations; 1) Central Water Commission, 2) Central Ground Water, 3) Central Ground Water Authority, 4)  Central Pollution Control Board . Laws, regulations and scheme regarding India's groundwater: 2019  Atal Bhujal Yojana  (Atal groundwater scheme), a 5 years (2020-21 to 2024-25) scheme costing INR 6 billion (US$854 million) for managing demand side with village panchayat level water security plans, was approved for implementation in 8,350 water-stressed villages across 7 states, including Haryana, Gujarat, Karnataka, Madhya Pradesh, Maharashtra, Rajasthan and Uttar Pradesh. 2013 National Water Framework Bill ensures that India's groundwater is a public resource, and is not to be exploited by companies through  privatization of water . The National Water Framework Bill allows for everyone to access clean drinking water, of the right to clean drinking water under Article 21 of  'Right to Life'  in  India's Constitution . The bill indicates a want for the states of India to have full control of groundwater contained in aquifers. So far  Andhra Pradesh ,  Assam ,  Bihar ,  Goa ,  Himachal Pradesh ,  Jammu & Kashmir ,  Karnataka ,  Kerala ,  West Bengal ,  Telangana ,  Maharashtra ,  Lakshadweep ,  Puducherry ,  Chandigarh ,  Dadra & Nagar Haveli  are the only ones using this bill.

17. In 2012,  National Water Policy  was updated, which had previously been launched in 1987 and updated in 2002 and later in 2012. In 2011, the Indian Government created a Model Bill for Groundwater Management; this model selects which state governments can enforce their laws on groundwater usage and regulation. 1882 Easement Act  gives landowners priority over surface and groundwater that is on their land and allows them to give or take as much as they want as long as the water is on their land. This act prevents the government from enforcing regulations of groundwater, allowing many landowners to privatize their groundwater instead accessing it in community areas. 1882 Easement Act's Section 7(g) states that every landowner has the right to collect within his limits, all water under the land and on its surface which does not pass in a defined channel .