Monitoring Water Quality

Pollution Assessment, Analysis, and Remediation

Satinder Ahuja, Satinder Ahuja

• Éditeur: Elsevier
• Année: 2013
• ISBN:
  9780444594044
• Sujet: Tecnologia e ingegneria
• Sous-sujet: Gestione ambientale

Monitoring Water Quality is a practical assessment of one of the most pressing growth and sustainability issues in the developed and developing worlds: water quality. Over the last 10 years, improved laboratory techniques have led to the discovery of microbial and viral contaminants, pharmaceuticals, and endocrine disruptors in our fresh water supplies that were not monitored previously.

This book offers in-depth coverage of water quality issues (natural and human-related), monitoring of contaminants, and remediation of water contamination. In particular, readers will learn about arsenic removal techniques, real-time monitoring, and risk assessment. Monitoring Water Quality is a vital text for students and professionals in environmental science, civil engineering, chemistry — anyone concerned with issues of water analysis and sustainability assessment.

• Covers in depth the scope of sustainable water problems on a worldwide scale
• Provides a rich source of sophisticated methods for analyzing water to assure its safety
• Describes the monitoring of contaminants, including pharmaceutical and endocrine disruptors
• Helps to quickly identify the sources and fates of contaminants and sources of pollutants and their loading

1

Monitoring Water Quality, Pollution Assessment, and Remediation to Assure Sustainability

Satinder (Sut) Ahuja, AHUJA CONSULTING, CALABASH, NC, USA

Chapter Outline

1.1 Introduction

1.1.1 What Is Potable Water?

1.1.2 Monitoring Water Quality

1.1.3 Monitoring Contaminants at Ultratrace Levels

1.1.3.1 Sampling and Sample Preparation

1.2 Water-Quality Status and Trends in the United States

1.3 Rivers in Africa Are in Jeopardy

1.4 Septic Systems in the Coastal Environment: Multiple Water-Quality Problems in Multiple Areas

1.5 Assessment of Risk from Endocrine-Disrupting Compounds

1.6 Water-Quality Monitoring and Environmental Risk Assessment

1.7 Analytical Measurements to Improve Nonpoint Pollution Assessments in Indiana’s Lake Michigan Watershed

1.8 Real-Time and Near Real-Time Monitoring Options for Water Quality

1.9 Advanced Oxidation and Reduction Process Radical Generation in the Laboratory and at Large Scale

1.10 Cactus Mucilage as an Emergency Response Biomaterial for Providing Clean Drinking Water

1.11 Potable Water Filter Development

1.12 Removal and Immobilization of Arsenic in Water and Soil Using Nanoparticles

1.13 Transforming an Arsenic Crisis into an Economic Enterprise

1.14 Monitoring from Source to Tap: The New Paradigm for Ensuring Water Security and Quality

1.15 Evaluation of Sustainability Strategies

1.16 Conclusions

Appendix

References

1.1 Introduction

Our civilization has managed to pollute our water supplies to the point where we have to purify water for drinking [1,2]. The expressions “clean as freshly driven snow” or “pure rainwater” are not true today. In the past, rain was nature’s way of providing freshwater; however, rain is usually contaminated by various pollutants that we add to our atmosphere. The shortage of affordable pure water forces an estimated 1.2 billion people to drink unclean water. As a result, water-related diseases kill 5 million people a year, mostly children, around the world. The problem does not seem to be getting any better—the UN estimates that 2.7 billion people will face water shortages by 2025.

Although earth is composed largely of water, freshwater comprises only 3% of the total water available to us. Of that, only 0.06% is easily accessible. This is reflected by the fact over that 80 countries now have water deficits. It is patently clear that water is a scarce and valuable commodity and we need to sustain its quality and use it judiciously, i.e. assure water sustainability. To achieve sustainability, we must ensure that as we meet our needs, we do not compromise the requirements of future generations [3].

Drinking water comes largely from rivers, lakes, wells, and natural springs. These sources are exposed to a variety of conditions that can contaminate water. The failure of safety measures relating to the production, utilization, and disposal of thousands of inorganic and organic compounds causes pollution of our water supplies. The overwhelming majority of water-quality problems are now caused by diffuse nonpoint sources of pollution from agricultural land, urban development, forest harvesting, and the atmosphere. These nonpoint source contaminants are more difficult to effectively monitor, evaluate, and control than those from point sources, such as discharges of sewage and industrial waste. Many water contaminants arise from the materials we use frequently to improve the quality of life:

• Combustion of coal and oil

• Detergents

• Disinfectants

• Drugs (pharmaceuticals)

• Fertilizers

• Gasoline (combustion products) and additives

• Herbicides

• Insecticides

• Pesticides.

The failure of safety measures relating to production, utilization, and disposal of a large number of inorganic/organic compounds encompassing the entire range of the alphabet, from arsenic to zinc, can cause contamination of our water supplies [4]. For example, whereas zinc in small amounts is desirable, arsenic at concentrations as low as 10 parts per billion (ppb) is quite harmful.

1.1.1 What Is Potable Water?

Expressed simply, potable water is any water suitable for human consumption. National Primary Drinking Water Regulations control water quality in the United States. Water-quality regulations vary in the different parts of the world. For instance, Table 1-1A in the Appendix shows what one municipality in the United States—Brunswick County in North Carolina—does to monitor water quality.

However, it should be noted that some of the contaminants of concern that are not monitored on a regular basis include:

• MTBE (methyl tertiary butyl ether)

• Herbicides

• Fertilizers

• Pharmaceuticals

• Perchlorate

• Mercury

• Arsenic

1.1.2 Monitoring Water Quality

Water quality and the monitoring of various contaminants, are discussed in this book. Among emerging contaminants of concern, the problem of pharmaceuticals and endocrine disruptors is gaining greater importance. It was recently reported that liquid formula is the biggest culprit in exposing infants to bisphenol A, a potential hormone-disrupting chemical extracted from plastic containers [5].

Hexavalent chromium, six perfluorocarbons, and seven sex hormones are among the 28 chemicals that utilities will have to test for in drinking water under the rules that the United States Environment Protection Agency (USEPA) finalized recently [5a].

Contaminants may also come from mother nature, even where the soil has not been degraded by pollutants from human beings. For example, natural processes like erosion and weathering of crustal rocks, can lead to the breakdown and translocation of arsenic from primary sulfide minerals. Contaminants from nature include arsenic, manganese, radionuclides, and a host of other chemicals. Though arsenic contamination of groundwater has now been reported in a large number of countries worldwide, Bangladesh has suffered the most from this contamination. Other countries affected by the arsenic problem include Argentina, Australia, Cambodia, Canada, Chile, China, Ghana, Hungary, India, Mexico, Nepal, Thailand, Taiwan, UK, the United States, and Vietnam.

Prolonged drinking of arsenic-contaminated water can lead to arsenicosis in a large number of people, eventually resulting in a slow and painful death. It is estimated that arsenic contamination of groundwater can seriously affect the health of more than 200 million people worldwide. Arsenic (As) contamination of groundwater can occur from a variety of anthropogenic sources, such as pesticides, wood preservatives, glass manufacture, and other diverse uses of arsenic. These sources can be monitored and controlled. However, this is not so easy with naturally occurring arsenic. The natural content of arsenic in soil is mostly in a range below 10 mg/kg; however, it can cause major crises when it gets into groundwater [2].

Arsenic contamination of groundwater is described below briefly, as it serves as an excellent example of how water purity and quality problems can occur if adequate attention is not paid to monitor all the potential contaminants. In Bangladesh, groundwater contamination was discovered in the 1980s [1,2]. A large number of shallow tube wells (10–40 m), installed with the help of the United Nations Children’s Emergency Fund (UNICEF) in the 1970s to solve the problem of microbial contamination of drinking water, were found contaminated with arsenic. The crisis occurred because the main focus was on providing water free of microbial contamination, a problem that was commonly encountered in surface water. Apparently, the project did not include adequate testing to reveal the arsenic. This unfortunate calamity could have been avoided, as analytical methods that can test for arsenic down to the parts-per-billion (ppb) level have been available for many years [6]. At times, speciation of a contaminant is necessary. For example, trivalent arsenic is more toxic than the pentavalent species. This demands a more selective method, and high pressure liquid chromatography-inductively couple plasma -mass spectroscopy (HPLC-ICP-MS) can resolve trivalent and pentavalent arsenic compounds at parts-per-trillion levels [7].

1.1.3 Monitoring Contaminants at Ultratrace Levels

It should be recognized that even with well-thought-out purification and reprocessing systems, trace (at parts-per million level) or ultratrace amounts (below 1 part-per-million level) of every substance present in untreated water is likely to be found in drinking water. To monitor contaminants in water, it is necessary to perform analyses at ultratrace levels. An example of ultratrace-level contaminants in drinking water in Ottawa, Canada, by gas chromatography/mass spectroscopy (GC/MS) is shown in Table 1-1 [8].

Table 1-1

Gas Chromatography/Mass Spectroscopy of Ottawa Tap Water

Compound	Concentration Detected in Ottawa Tap Water (ppt)
α-Benzene hexachloride	17
Lindane	1.3
Aldrin	0.70
Chlordane	0.0053
Dibutyl phthalate	29
Di(2-ethylhexyl) Phthalate	78

At ultratrace levels, sampling and sample preparation should be given great attention.

1.1.3.1 Sampling and Sample Preparation

It is abundantly clear that the sample used for ultratrace analysis (analysis at ppb level) should be representative of the “bulk material.” The major considerations are [9]:

(1) Determination of the population of the “whole” from which the sample is to be drawn.

(2) Procurement of a valid gross sample.

(3) Reduction of the gross sample to a sample suitable for analysis.

The analytical uncertainty should be reduced to a third or less of sampling uncertainty [10]. Poor analytical results can also be obtained because of reagent contamination, operator errors in procedure or data handling, biased methods, and so on. These errors can be controlled by the proper use of blanks, standards, and reference samples. It is also important to determine the extraction efficiency of the method.

Preconcentration of the analyte may frequently be necessary because the detector used for quantitation may not have the necessary detectability, selectivity, or freedom from matrix interferences [11]. Significant losses can occur during this step because of very small volume losses to glass walls of recovery flasks or disposable glass pipettes and other glassware. However, with suitable precautions, preconcentration of metals at concentrations down to 10⁻¹² g/g for copper, lead, and zinc, and 10⁻¹³ g/g for cadmium have been successfully demonstrated in a typical polar snow matrix [12]. The reader may benefit from the sample-collection techniques used by Chakraborti to analyze thousands of samples in the investigation of the problems of arsenic contamination of groundwater in various regions of Bangladesh and India (see Chapter 5 in Ref. [1]).

Discussed below are examples of water problems from point and nonpoint source pollution in underdeveloped countries, as experienced in Asia, Africa, and Latin America; as well as in developed countries as exemplified by the United States. Also discussed at length are methods used to monitor the assessment of risk of contaminants and the various remediation approaches used to achieve the desired water quality.

1.2 Water-Quality Status and Trends in the United States

Information on water quality is critical to ensuring long-term availability and sustainability of water that is safe for drinking and recreation, and suitable for industry, irrigation, and fish and wildlife (Chapter 3). Water-quality challenges are increasingly complex. First, the majority of water-quality problems are now caused by diffuse nonpoint sources from agricultural land, urban development, forest harvesting, and the atmosphere. These nonpoint-source contaminants are more difficult to effectively monitor, evaluate, and control than contaminants from point sources, such as discharges of sewage and industrial waste. Concentrations can vary from hour to hour and season to season, making it difficult to monitor and quantify possible effects on the health of human and aquatic ecosystems. A second challenge facing us is emerging diversity in water-quality issues. The dominant concerns regarding water quality were focused largely on the sanitary quality of ri...