Environmental Chemistry : Water and Soil Pollution

INTRODUCTION

Environmental science is the systematic study of the interaction of two worlds. The word ‘Environment’ is derived from an old French word ‘environ’ meaning ‘encircle’. The environment consists of four segments: atmosphere, hydrosphere, lithosphere and biosphere.

Among all of substances, water is a marvelous substance on earth. Water is one of the abundantly available substances in nature. Water is essential for all kinds of life and is the medium in which all living processes occur. Water is renewable source, but renewable takes time. The hydrological cycle constantly purifies and redistributes fresh water on landmasses, providing endless renewable resource.

At present, there are many environmental issues, which have grown in size and complexity day by day, threatening the survival of mankind and all living organisms on earth. Unfortunately, with progress in science and technology, man has been dumping waste material into atmosphere and causing pollution. Environmental pollution can be divided among the categories of water, air and soil pollution. Emission of pollutants in air, water and soil has caused considerable damage to our environment.

Water pollution disturbs the normal uses of water for irrigation, agriculture, industries, public water supply and aquatic life. Most of the human activities produce liquid effluents, which are the prime cause of water pollution. Rapid increase in population, intensive agriculture, growing industrialization and urbanization has resulted in progressive deterioration in the quality of water in our natural reservoirs.

Most of the water related diseases are some way or other concerned with the polluted water supply. Water borne infections diseases like cholera, dysentery, typhoid, jaundice and worm infection are still the major public health problems in developing countries.

Another substance, which plays a very important role, is soil as it produces food for human beings and animals. Soil is a complex of physical and biological systems, which give support to the plants and supplies water and essential nutrients to them. It is the main reservoir of the minerals essential for normal growth of the plants.

The soil consists of four major components, i.e. mineral matter, organic matter, soil air and soil water. All these components cannot be separated with much satisfaction because they are present very intimately mixed with each other. With careful husbandry, soil can be replenished and renewed indefinitely.

Hazardous chemicals heavily pollute soil day by day. Disposal of industrial waste is the major problem responsible for soil pollution. These waste products are also tipped on soil, enhancing the extent of soil pollution. As a result, hazardous chemicals can enter into human food chain from the soil or water, disturb the biochemical process and finally lead to serious effects on living organisms.

Large-scale soil and water pollution is one of the primary factors behind the high prevalence of soil and water borne diseases. Soil degradation can reduce the quality of our food, whereas deforestation can reduce the availability plants to make current medicines and medicines for the future.

Heavy metal pollution has also a serious impact. Metal pollution can affect all environments but its effects most long lasting in soil. Drinking is one of the major routes of intake of heavy metals by the human body. Soil contamination should be a primary concern in India, because the country relies heavily on agriculture. Toxic metal is the one, which is neither essential nor beneficial but exhibits a positive catastrophic effect on normal metabolic function even when present in small amounts and may, at times, be responsible for permanent disorders or malfunctioning of organ system leading finally to death.

This BOOK consists of five chapters.

CHAPTER 1: INTRODUCTION

This chapter is divided into two parts:

1A: WATER

This part contains Introduction of Water, Properties of Water, Major Water Compartments, Types & Forms of Water, Water and its Significance, Potability of Water, Water Consumption Pattern & Demand, Water Resources, Water Quality for Irrigation and Ground Water Quality Status in Rajasthan.

1B: SOIL & VEGETATION

This part contains Introduction of Soil, What is Soil?, Composition of Soil, Process of Soil Formation, Soil Profile, Soil Texture, Types of Soil, Soil pH, Life on Soil, Macro and Micro Plant Nutrients, Functions of Various Nutrients and Agricultural Status w.r.t. Soil.

CHAPTER 2: WATER & SOIL POLLUTION

This chapter is divided into two parts:

2A: WATER POLLUTION

(i)           This part contains Environmental Pollution, Water Pollution, Causes of Water Pollution, Sources of Water Pollution, Types of Water Pollution, Classification of Pollutants, Types of Pollutants, Characteristics of Fresh Water, Chemical Characteristics of Water, Characteristics of Industrial Wastes, Control of Water Pollution, Diseases Caused by Water Pollution, Various Effluents and Their Effects on Aquatic Organisms, Fluoridation and Defluoridation of Water, Water Management, Water Pollution in India and Water Pollution in Rajasthan.

(ii)         2B: SOIL POLLUTION

This part contains Soil Pollution, Sources of Soil Pollution, Diseases Caused by Soil Pollution, Control of Soil Pollution, Heavy Metal Toxicology, Sources of Heavy Metals and Environment Friendly Technologies.

CHAPTER 3: METHODS & METHODOLOGY

METHODOLOGY FOR WATER

Wastewater samples were collected from eleven different sites from the ‘AMANISHAH NALA’ and groundwater (Hand pump) samples were taken from nine different vicinal locations of various industrial sites. Samples were collected in good quality screw–capped polyethylene bottles of one litre capacity, labeled properly and analyzed in laboratory for their all physico–chemical parameters. Monitoring was done during the three seasons (pre-monsoon, during monsoon and post-monsoon) throughout the two-years from different industrial areas and adjacent places of Jaipur city (June, 2002 to May, 2004).

Various physical parameters like pH, EC, DO and TDS, which are important to evaluate the suitability of wastewater for irrigation, were determined on the site with the help of digital portable water analyzer kit (CENTURY–CK–710). For rest of the analysis, water samples were preserved and bought to the laboratory. The chemical analysis carried out for BOD by incubation method, COD by KMnO₄ method, Calcium (Ca²⁺), Magnesium (Mg²⁺), Chloride (Cl^–), Sulphate (SO₄^2–), Carbonate (CO₃^2–) and Bicarbonate (HCO₃^–) by volumetric titration methods; while Fluoride (F^–) by spectrophotometric (AIMIL–C160–80314) & ion selective electrode method and Nitrate (NO₃^–) by spectrophotometric (ELICO–CL–54D) method; Sodium (Na⁺), Potassium (K⁺) by flamephotometry (ELICO–CL–220) and heavy metals by AAS.

In order to estimate the quality of the groundwater for drinking purposes, an indexing system, Water Quality Index (WQI), based on Adak and Purohit(20), was determined.

Evaluation of the quality of wastewater on the basis of percent sodium (%Na) is excellent, was determined. Quantitatively, United States Salinity Laboratory (USSL) proposed, for the first time, a better index called ‘Sodium Absorption Ratio (SAR)’, was determined. Sodium hazard of irrigation water can be well understood by knowing SAR. There is a significant correlation between SAR values of irrigation water and the extent to which sodium is absorbed by the soil.

METHODOLOGY FOR SOIL

Soil samples were collected from thirteen different vicinal locations of various industrial sites where industrial wastewater use for irrigation. Samples were collected in good quality polyethylene bags, labeled properly and analyzed in laboratory for their all parameters. Monitoring was done during the four intervals throughout the year from different vicinal locations of various industrial sites of Jaipur city where industrial wastewater use for irrigation (April, 2004 to March, 2005).

Soil samples may be analyzed for the following parameters like: pH, EC, Organic Carbon, Nitrogen, Phosphorous, Potassium, Fe, Zn, Cu, Mn, etc.

CHAPTER 4: RESULTS AND DISCUSSION

This chapter is divided into three parts:

4A: WATER FOR DOMESTIC PURPOSES

In these sites, positive correlation between surface and ground water was recognized. The groundwater near solid waste and liquid waste disposal sites was polluted, whereas the groundwater away from disposal sites was not much affected.

The values obtained were compared with standards of ISI, ICMR and WHO. From the observations, it may inferred that the concentration of pH, EC, Ca²⁺, Na⁺, K⁺, Mg²⁺, SO₄^2–, CO₃^2–, HCO₃^2–, Cl^–, DO and BOD are within permissible limits of ISI, ICMR & WHO but NO₃^–, TDS, TH, COD and WQI values show the poor water quality in most of the studied groundwater samples taken from vicinal locations of various industrial sites. Concentrations of all heavy metals like Cr, Cu, Cd, Mn, Ni, Pb, Fe, As & Zn are within permissible limits. Higher concentrations of Zn in very few samples have been observed.

WQI values of these samples were ranging from 35.08 to 268.78 which means that only 37.5% sample’s water were fit for human consumption directly, but 62.5% water of all sources can be used for domestic consumption after appropriate treatment whereas remaining 37.5% water of samples were of very poor quality and was not recommended for domestic purposes. So it may be accomplished with the help of WQI that the water of the various samples were unfit for drinking purpose without further treatment (mainly disinfections).

It may be concluded that the general characteristics of groundwater samples from the study area classify the water under moderate category and are tolerable for household and commercial purposes However, high WQI and COD values suggest purification may be necessary for domestic consumption.

4B: WATER FOR IRRIGATION PURPOSES

The suitability of groundwater and wastewater for irrigation depends upon its mineral constituents. The salts present in the water, besides affecting the growth of the plants directly also affect the soil structure, permeability and aeration, which indirectly affect the plant growth.

Jaipur is undergoing rapid urbanization and industrialization.Wastewater generated from various industries discharged into ‘AMANISHAH NALA’ where this water is used for irrigation purpose. The values obtained were compared with standards of ISI, ICMR and WHO. The concentrations of pH, Na⁺, K⁺, Ca²⁺, Mg²⁺, SO₄^2–, CO₃^2–, HCO₃^–, TH, Cl^–, NO₃^–, Oil & Grease, DO and F^– are within permissible limits in both groundwater and wastewater but definite contaminations with special reference to EC, TDS, BOD and COD in wastewater have been observed, calls for at least primary treatment of wastewater before being used for irrigation. High EC and TDS values reflect greater salinity of water and it cannot be suitable for irrigation under ordinary conditions. There was also a significant correlation between SAR values of irrigation water and the extent to which sodium is absorbed by the soil.

No excellent conclusion can be drawn to observed values but general conclusion can be drawn as: The general characteristics of groundwater and industrial wastewater samples from the study area classify the water under moderate category and are good for household, irrigation and commercial purposes and results of suitability evaluation indicate that there is no major pollution hazard in wastewater of AMANISHAH NALA. However, high BOD and COD values suggest purification may be necessary for sensitive crops and human consumption.

4C: SOIL FOR AGRICULTURAL PURPOSES

In all studied locations, soil is moderate for all kinds of crops except sensitive ones. Adjacent locations of all industrial areas under study have concentrations of pH, EC, organic carbon, Fe, Cu and Mn are within permissible limits and show good soil quality in most of the studied soil samples taken from vicinal locations of various industrial sites. There is lack of concentrations of Zn is all soil samples and is need to give zinc sulphate fertilizer to compensate this but definite concentrations of P and K in soil samples have been observed at critical limit. Some samples also have higher pH i.e. alkaline in nature and they need to give gypsum for reducing alkalinity from soil samples.

CHAPTER 5: WASTEWATER TREATMENT AND

SUGGESTIONS

The ultimate disposal of wastewater can only be onto the land or into the water. But whenever the watercourses are used for the ultimate disposal, the wastewater is given a treatment to prevent any injury to the aquatic life in the receiving water. Normally, the treatment consists of the removal of suspended and dissolved solids through different units if the treatment plants.

The treatment of industrial wastewater may be accomplished in part or as a whole either by the biological processes, as done in the sanitary sewage, or by processes very special for the industrial wastewater only. Depending upon the constituents present in it, the treatment may consist of any one or more treatment (chemical or biological or both) processes. The chemical treatment should be provided only when it becomes unavoidable. The selection of the particular treatment process depends on the effluent requirements and the characteristics of the waste.

Today it is not enough to emphasize the protection of the environment. The fundamental purpose of water treatment is to remove impurities that may be offensive or injurious to health and well being of the individual and community.Disinfectant should kill the pathogens quickly at room temperature. It should be inexpensive, and non-toxic, to humans and should provide protection against only contamination in water during conveyance or storage.

The Govt. should immediately make laws banning industrial pollution. Failure to do so will lead to substantial penalties and fine. The water treatment plants should be installed in rural areas. The rural inhabitants should try to avoid the use of pesticides in their fields. All small scale and big industries must have anti-pollution unit. Create the awareness about the effects of high concentration of nitrate, fluoride, solids and hardness among villagers. Through strict implementation of the Government’s Water Treatment Programme, water can be rendered safe for drinking.

Chapter 1, 2, 3 & 5 precisely details under various heads and chapter 4 details under water for domestic & irrigation purposes and soil for agricultural purposes, results, discussion, tables and graphs of each parameters results, evaluations, assessments and comparison followed by a comprehensive list of relevant references after everything else of the BOOK.