Patrick J. Sullivan

The Water We Drink

In a landscape dominated and modified by human activity, it is not be surprising that the water one drinks contains both chemical and biological pollutants. Environmental science evaluates how humans use the earths natural resources, appraises the repercussions that occur as the result of this use, and evaluates how to mitigate these impacts. Because water that exists at and below the earths surface is in contact with soil and rock, some mineral or organic matter is dissolved in it. Based on the natural properties of water (H 2 O) and the properties of each chemical element and mineral combination, the actual occurrence and concentration of an element in water can vary widely. Another crucial chemical property of water is its relative acidity or alkalinity. This chemical characteristic has a direct influence on the concentration of minor elements and trace elements. Many of the compounds found in natural water are the result of biosynthesis and biodegradation. As a result, natural water can contain a wide range of organic compounds. The chemistry of natural water is highly dependent on its geologic and hydrologic origins, as well as its biological contributions. The imparted chemical characteristics to natural water can be highly valued or a potential threat to public health. The federal government essentially issued a license to allow water resources to be polluted up to an acceptable level. As a natural consequence of setting water quality criteria, specific definitions for the terms contamination and pollution were developed.

7 – SYNTHETIC CHEMICAL CONTAMINANTS IN DRINKING WATER

Hazardous microorganisms, dissolved toxic metals, radioactive elements from rock, and poisonous synthetic chemicals from human activities can pollute water. Of all these hazards, a microbial infection can result in illness or death within days of contact. This means that safe drinking water must be free of hazardous microorganisms, or be treated to ensure that microbial levels pose no risk to human health. A safe drinking water product meets all federal or state maximum contaminant levels (MCLs) for biological, radioactive, inorganic, and organic constituents, and also contains no more than one detected synthetic organic chemical. Consumers should know how synthetic chemicals contaminate the drinking water resources, and consumers who are serviced by a water utility should review the utilitys annual water quality report. With this information, each consumer can determine if in-home treatment or bottled water would be a safer alternative. The synthetic chemicals that are known to pollute water resources are pesticides, organic industrial chemicals and petroleum products, pharmaceuticals, and disinfection by-products. It is important to note that relative to the disinfection by-products that occur in treated drinking water, two general parameters reflect the sum of several individual contaminants: the concentration of the total trihalomethanes (TTHM) are the sum of the concentrations of bromodichloromethane, bromoform, chloroform, and dibromochloromethane, and, the concentration of the haloacetic acids (HAA) is the sum of the concentrations of dibromoacetic acid, dichloroacetic acid, monobromacetic acid, monochloroacetic acid, and trichloroacetic acid.

CHAPTER 3 – Water Protection

Publisher Summary The basic elements of a typical large water treatment plant have four objectives: pretreatment, prefiltration, filtration, chemical treatment, and disinfection. Although treatment is necessary to improve the quality of drinking water, the process also creates its own pollution problems. The standard methods of water treatment used by water utilities can add suspected carcinogens to treat water by: the addition of organic flocculants to remove suspended solids, by the use of chlorine, chloramine, or bromine to destroy biological hazards, and the subsequent creation of disinfection by-products. The ability of a water treatment facility to deliver a wholesome and high quality product to its consumers usually occurs when advanced treatment methods are used. Some of the more advanced technologies used today focus on the ability to use instrumentation to control the optimal quantities of chemicals needed in process operations. Such instrumentation is also used to continuously monitor water quality throughout the water treatment process. In addition to instrumental controls, numerous advanced treatment methods can be used to reduce both biological and chemical pollutants. The use of advanced instrumentation in water treatment systems is an obvious benefit to a water utility, because these technologies save money on chemicals and labor. In the industrialized nations, a great deal of attention is placed on risks associated with synthetic organic chemicals in the very low ppb range. This is certainly not true in the developing nations where the greatest concern continues to be directed on bacterial contamination.

CHAPTER 4 – Living with the Risk of Polluted Water

Publisher Summary Most people believe, at a gut level, that environmental factors such as the exposure to chemicals, exposure to airborne smoke and particulates, stress, drug and alcohol use, diet, electromagnetic fields, and radiation can contribute to or cause health problems. The delay in recognizing the impact of chemicals on human health is another layer of risk that is intrinsic to a “standard-based” pollution control policy. The Centers for Disease Control (CDC) reported the results of a 1999 study that tested for the presence of 27 chemicals in the blood and urine of 5000 individuals throughout the United States. The results of the initial study showed that elevated concentrations of mercury and phthalates were found in the human body, and especially in women and children. In addition, a Public Broadcasting System report on chemical industry trade secrets by Bill Moyers in March 2001 described the presence of industrial chemicals in human blood. These reports clearly indicate that industrial chemicals permeate our bodies. The potential risk to human health is obvious. Determining the extent to which precautionary measures are needed is the major problem in attempting to address any threat to human health. Although the application is complex, there are also solutions, some of which are also complex, that can meet this challenge. The precaution principle must be incorporated into the pollution policies of today, while reasonable solutions are still viable. Seeking alternative methods of risk management that address polluted drinking water is highly advisable.

5 – DIETS AND CHEMICAL MIXTURES

This chapter provides examples of how individual food choices influence a persons chemical exposure. The first example compared the daily chemical exposure of a balanced high-fat and low-fat diet using individual food products that are non-organic. The comparison showed that the low-fat diet had 19 different chemicals, whereas the high-fat diet had only 17, but the high-fat diet had a greater number of banned chemicals that are found in multiple foods. The second example looked at chemical exposures that occur in a vegetarian diet. In this example, a strict vegetarian diet was compared to a vegetarian diet that includes eggs and dairy products. It was concluded that vegetarian diets would generally contain fewer banned pesticides than diets that include protein and dairy products. Another good example of a chemical-exposure comparison is a childs lunch box, whose school lunch may include both homemade and commercially prepared products. When considering the number of chemicals that occur in the mixed food category, parents should seriously consider using prepackaged products and switch to homemade food made from organic products.

3 – THE NUMBER OF SYNTHETIC CHEMICALS IN FOOD

The total number of chemical contaminants varies widely depending on the food product category. Data collected shows that the least contaminated food category is the child/infant category, while mixed foods contain the greatest average number of contaminants per food. Dairy products with high-fat content are more contaminated, with butter being significantly more contaminated than the other dairy products. Processed meats contain more chemicals than muscle products. Adult foods with high numbers of chemical contaminants occur in childrens food at relatively higher levels. If parents are not satisfied with the level of contaminants in some of the food tested by the FDA, they have two basic choices. They can either select organic child and infant products or they can prepare child and infant food from organic products. Fruit data shows several distinctive trends: the juice of a fruit generally has fewer contaminants than the parent fruit, the dark green and yellow vegetables tend to contain elevated contaminant levels along with salad vegetables, and that vegetable oils, margarine, and olives contain elevated contaminant levels. If ones goal is to eat safer foods, then he or she should choose the food that contains, on average, one or fewer synthetic chemicals, and also minimize the consumption of food with more synthetic chemicals.

1 – CONFRONTING THE UNKNOWN

The three most common chemical pollutants in water are Valium, estrogen, and diuretics. Wastewater containing pharmaceuticals is discharged into creeks, rivers, lakes, and groundwater, and the same water eventually becomes someones drinking water. Nothing has changed since 1983, except for the type and number of different drugs that are currently being found in the water resources. In todays water, one also finds drugs such as Prozac, aspirin, ibuprofen, cholesterol–lowering drugs, and even chemotherapy chemicals. DDT and its metabolites (DDE and TDE) are classified as poisonous or deleterious substances in human food and have established tolerance levels that range from 50 to 500 ppb. There are no federal exposure limits for any toxic chemical in the air that occurs outside the work environment. Instead, facilities that release air toxins into the atmosphere are required to limit the amount of their emissions. Motor vehicles, however, are exempt from any limitations on their release of toxic chemicals into the atmosphere. Thus, the quality of the air is affected by toxic emissions in both localized neighborhoods and within metropolitan areas. It is appropriate and realistic to assume that the greater the number of synthetic chemicals to which a person is exposed, the greater the probability an individual may experience either a synergistic or additive health effect.

8 – SYNTHETIC CHEMICAL CONTAMINANTS IN AIR

The inherent complexity of the atmosphere and the difficulty of monitoring and assessing chemical exposures require the close cooperation of federal, state, and regional air pollution agencies to control air toxins. Toxic emissions are controlled by placing limits on the amount of specific chemicals that can be released to the atmosphere, but they are not eliminated. The United States uses or manufactures about 72,000 chemicals. The Environmental Protection Agency (EPA) has identified 188 of these chemicals as hazardous. The EPA has placed emission limits on these 188 hazardous chemicals and requires that an industry report the amount each facility releases. The state air pollution control agencies actually determine the concentration of selected hazardous chemicals in the environment through 264 state-maintained monitoring stations. The program focuses on monitoring 33 urban hazardous air pollutants that represent the most hazardous threat to public health in urban environments. In addition to air monitoring, this program also tracks the amount of hazardous air emissions released by industrial sources using the Toxic Release Inventory (TRI). Benzene, Toluene, and Xylene are some of the common toxins found in the air.

6 – FOOD CONTAMINATION AT THE CITY AND REGIONAL LEVELS

It is possible to identify the cities with the highest and lowest number of chemical contaminants in their food products within a given market basket. The greater the number of detected chemical contaminants, the greater ones potential exposure to chemical mixtures. The chemical diversity within a market basket can be expressed by determining the number of different pesticides and industrial chemicals that actually contaminate food within the basket. The chapter ends with the conclusion that a market basket with a high number of contaminants and chemical diversity will expose the consumers to a much more complex chemical mixture than a market basket with fewer chemical contaminants with less chemical diversity.

9 – TOXICITY AND SYNTHETIC CHEMICAL MIXTURES

It is important to understand how individual synthetic chemicals and mixtures of synthetic chemicals in the environment can have a far-reaching impact on ones life. An example of the significant toxicity of halogenated hydrocarbons is demonstrated in 2-bromo-2-chloro-1,1,1-trifluoroethane (Halothane). Multiple exposures to halothane increase the risk of developing two types of liver damage. Type I hepatotoxicity is benign and self-limiting while Type II hepatotoxicity is immune-mediated and is initiated by an oxidative halothane metabolism to an intermediate compound. Bioaccumulation is the process by which chemicals are stored in the bodies of exposed individuals, increasing in concentration over time. The continued accumulation of synthetic chemicals in the body can therefore be very significant in determining the overall health of the individual or the persons offspring. While breast milk is the most important food for newborns and infants during critical periods of development, it may also be the primary route of exposure to many unsafe environmental contaminants. Polybrominated Diphenyl Ethers (PDBEs) are one of the most prevalent chemicals found in maternal milk. DDT was used as a pesticide and enters the body through fruits, vegetables, fatty meat, fish, poultry, and contaminated drinking water. In the environment, DDT degrades into DDE and DDD. DDT in breast milk is prevalent worldwide. The chemicals of concern affect a number of target organs. The impact to each system by synthetic chemicals must be accounted for when evaluating the toxicity of chemicals.