What occurs when a water oxygen level has been depleted because of the rapid growth of algae?

Abstract

Eutrophication is defined as an increase in nutrient input to surface waters to the extent of overenrichment, with a corresponding increase in primary productivity and related negative effects. Eutrophication is widely recognized as a serious, primarily human-caused (anthropogenic) environmental issue. The process of nutrient transport is explored starting with water as both a molecule and substance, and its passage over and through the landscape to aquatic systems. Two primary nutrient cycles, phosphorus (P) and nitrogen (N), are discussed with focus on anthropogenic perturbations and their cumulative effects. Consideration is given to states of ecological succession, natural and cultural eutrophication, fire, drought, and instances where increased nutrient loading does not result in eutrophication. Nutrient concentrations and ratios (N:P) are reviewed for their effects on phytoplankton growth and potential for cyanobacteria, capable of toxin production, to dominate phytoplankton communities. Two case studies are presented to contrast the impacts of point- and nonpoint-source pollution. Lake and watershed features are discussed in the context of aquatic system response following nutrient input and speed of recovery after commencement of mitigation efforts. Watershed management examples as well as topics for future research are presented.

1 Introduction

Eutrophication in most water bodies is an important environmental problem. It is caused by increasing nutrient loading associated to urban, industrial and agricultural activities. Eutrophication is associated to accelerated growth of phytoplankton (algal blooms). The presence of certain species of cyanobacteria within the blooms is of special care, as they may produce hepato- and neurotoxins that can severely compromise human and animal health. To address nutrient point sources, such as urban and industrial, much effort has been devoted to the development of wastewater treatment processes and facilities (Gernaey et al., 2004; Karuppiah and Grossmann, 2008). However, nonpoint nutrient sources, such as those associated to agricultural activities, have not received much attention (Estrada et al., 2009). In particular, increased eutrophication can be a key feature associated to the large-scale production of biofuels from energy crops when compared to fossil fuels. The life cycle wide emissions of nutrients depend on the application and losses of fertilisers during the agricultural production of biofuel feedstocks. External restoration techniques for nonpoint sources include the construction of artificial wetlands nearby the water bodies to remove nutrients and, in this way, decrease nutrient loading. Within in-lake restoration strategies, biomanipulation is based on the trophic chain theory and it has been applied to control phytoplankton growth in lakes and reservoirs. The basic idea is to keep a high grazing pressure on the phytoplankton community by the herbivore zooplankton by performing zooplanktivorous fish removal (Sondegaard et al., 2007). Another in-lake restoration strategy is hypolimniom aeration, so as to precipitate phosphorous compounds to the sediment, not becoming available for phytoplankton production. Three dimensional eutrophication models have been proposed for large lakes with horizontal uneven distributions (Hu et al., 2006) and for costal systems (Moll and Radach, 2003). In this work, we formulate a three-dimensional eutrophication model, based on a previous one-dimensional model (Estrada et al.; 2010) for a reservoir that provides drinking water for two cities in Argentina. The model is based on first principles, with parameters that have been tuned with collected data from the specific reservoir under study (Estrada et al., 2009). It includes dynamic mass balances for three phytoplankton groups and main nutrients. The model is developed within a control vector parametrization dynamic optimization framework in which the water body has been spatially discretized in volume elements. Numerical results provide quantitative information for planning restoration strategies over a one year horizon, as well as its effect on algae growth and nutrient concentration.

9.08.1.1 Aspects of Worldwide Concern over Eutrophication

Eutrophication is the nutrient enrichment of waters that stimulates an array of symptomatic changes, that can include increased phytoplankton and rooted aquatic plant (macrophyte) production, fisheries and water quality deterioration, and other undesirable changes that interfere with water uses (Bartsch, 1972). The trophic state, or degree of fertility, of water bodies ranges from oligotrophic to mesotrophic to eutrophic with increasing supply of nutrients and organic matter (Table 1). Eutrophication is most often the result of an elevated supply of nutrients, particularly nitrogen and phosphorus, to surface waters that results in enhanced production of primary producers, particularly phytoplankton and aquatic plants.

Table 1. Mean annual values for the trophic classification system

Source: OECD (1982).

Phytoplankton are unpleasant at high densities. The sight and smell of clots or masses of decaying phytoplankton decreases the recreational value of most waters and usually generates concerns among the public. Furthermore, blooms of toxin-producing phytoplankton can cause widespread illness. A bloom is a conspicuous concentration of phytoplankton, often concentrated at or near the surface. It is difficult to quantify what constitutes a “bloom,” but a rough estimate places it as a chlorophyll a concentration over 30 μg L−1. Toxins produced by dinoflagellates such as Pfiesteria in marine environments of the northeastern US and red tides in tropical waters have caused massive fish kills, millions of dollars in losses to seafood-related industries, human memory loss, paralysis, and even death (Van den Hoeck et al., 1995; Silbergeld et al., 2000). Bloom-forming species of cyanobacteria can produce potent hepato-(liver) toxins termed microcystins that have been implicated in poisonings of domestic livestock, pets, wildlife, and susceptible humans (Codd, 1995; Dunn, 1996). In addition, an accumulation of dead phytoplankton in bottom waters of eutrophic systems can lead to high decomposition rates by bacteria. Dissolved oxygen consumption by decomposers, combined with a barrier to gas exchange (thermocline or ice cover), can reduce (hypoxia) or eliminate (anoxia) dissolved oxygen in bottom waters. (A thermocline is the junction between an upper layer of warm, less dense water (the epilimnion) and a deeper layer of cold water (the hypolimnion). When this stratification is in place, the typically oxygen-rich waters of the epilimnion do not mix with the waters of the hypolimnion.) Oxygen depletion is one of the most harmful side effects of eutrophication because it can cause catastrophic fish kills, devastating local fisheries.

The accumulation of plant biomass depends on the addition of factors that stimulate plant growth. On average, the macronutrients nitrogen and phosphorus are present in marine phytoplankton at an atomic ratio 16 : 1 (Redfield, 1958). The ratio of nitrogen to phosphorus in freshwaters tends to be greater than the ratio in phytoplankton; therefore, phosphorus most often limits the growth of phytoplankton. As a result, phosphorus enrichment of freshwater often causes its eutrophication (Schindler, 1977). In lakes, nitrogen is usually present in concentrations equal to or beyond what is required for aquatic plant growth because, unlike phosphorus, it has an atmospheric source. In marine systems, nitrogen concentrations are often limiting because bacterial nitrogen fixation, while a considerable source of nitrogen in lakes, not as important in marine waters. A wide variety of prokaryotic organisms (i.e., certain cyanobacteria, heterotrophic, and chemoautotrophic bacteria) can use nitrogen gas directly and incorporate it into organic compounds through a process called nitrogen fixation. Nitrogen fixation is an enzyme-catalyzed process that reduces nitrogen gas (N2) to ammonia (NH3). Nitrogen-fixing cyanobacteria make up less than 1% of the total biomass of phytoplankton in estuaries of the Atlantic coast of North America, whereas in lakes they often make up more than 50% of phytoplankton biomass (reviewed in Howarth, 1988). An increase in water clarity can also spur the growth of aquatic vegetation in systems where the clarity of water is poor from high concentrations of suspended particles.

The biodiversity of most aquatic systems decreases with eutrophication (Figure 1). Phytoplankton species diversity is reduced in highly productive systems. Cyanobacteria are usually dominant in eutrophic systems because these organisms are better adapted to conditions of high nutrients (Smith, 1986; Trimbee and Prepas, 1987; Watson et al., 1997). In addition, fish and macro-invertebrate species diversity can decrease with eutrophication. Depletion of dissolved oxygen in deep water is associated with eutrophication and can lead to a loss or displacement of species intolerant of such conditions (Ludsin et al., 2001). In eutrophic lakes of North America, characteristic fish types are surface-dwelling, warm water fishes such as pike, perch, and bass, as compared to deep-dwelling, cold-water fishes like salmon, trout, and cisco (Ryding and Rast, 1989).

The Death of Lake Erie: The Price of Progress?

The demise of Lake Erie in the 1960s was emblematic of the environmental challenge growing out of the industrial and petrochemical revolutions of the nineteenth and twentieth centuries in the West. Companies, municipalities, and people in general had seemingly perceived water to be completely elastic in its ability to absorb any amount and type of pollution. Any waste that needed to be disposed of was directly discharged into surface waters, such as rivers, lakes, and oceans.

Lake Erie provides numerous lessons. For those of us who were learning the new language of environmental science, Lake Erie gave us a new paradigm, one of optimism where even highly polluted waters could be saved. For the decades that followed the 1960s, water bodies began to recover from even extremely polluted conditions. Although the science of limnology (the study of freshwater systems) had been well established within the hydrologic and biological science communities, the problems in Lake Erie helped to propel it into a much wider application. For example, eutrophication of freshwaters, especially ponds and lakes, became better understood in the context of Lake Erie (see the discussion box, “Eutrophication”).

Eutrophication

Healthy water bodies contain sufficiently low amounts of contaminants and sufficiently high amounts of dissolved oxygen (DO) to support a balance of aquatic life. The DO concentrations in surface waters can be reduced by both natural and human factors. Evidence of a healthy water body is its trophic state. Every lake fits into a particular trophic state, according to its degree of eutrophication, and all lakes change their trophic status over time. All lakes, even the most pristine, are undergoing nutrient enrichment and filling. Lakes can be divided into three categories based on trophic state—oligotrophic, mesotrophic, and eutrophic. These categories reflect a lake’s nutrient and clarity levels.

Limnologists refer to healthy water bodies as oligotrophic systems; that is, they contain little plant nutrients and are often continuously cool and clear. Oligotrophic waters have very low production of organic matter by photosynthesis and can support diverse animal life and collect optimal amounts of nutrients, mainly phosphorous and nitrogen, from natural sources, such as decomposing plant matter. When a water body becomes enriched in dissolved nutrients, especially phosphorous and nitrogen, they stimulate the growth of aquatic plant life, which can lead to the depletion of dissolved oxygen (DO). This is known as eutrophication.

Oligotrophic lakes (see Figure 4.1) are generally clear, deep, and free of weeds or large algae blooms. Though aesthetically appealing, they are low in nutrients and do not support large fish populations. Nutrient concentrations, such as phosphorous and nitrogen, are limiting, and aquatic macrophytes (large plants) and algae are less abundant. Oligotrophic water bodies typically have accumulated little plant debris on the bottom over the years since aquatic macrophytes and algae are less abundant. They generally have water clarity greater than four meters (i.e., the distance one can see down into the water) since the amounts of free-floating algae are low, as well as the absence of presence of coloring agents in dissolved substances and low concentrations of suspended particles. Fish and wildlife populations generally will be small because food and habitat are often limited. Oligotrophic water bodies usually do not support abundant populations of sportfish such as large-mouth bass and bream, and it usually takes longer for individual fish to grow in size in oligotrophic waters. However, oligotrophic lakes often develop a food chain capable of sustaining a very desirable fishery of large game fish, but these conditions can deteriorate in a short amount of time due to fishing pressure increases.

A mesotrophic lake (see Figure 4.2) can support moderate populations of living organisms. These lakes have moderate concentrations of nutrients and moderate growth of plant life, such as algae and/or macrophytes, owing to the moderate concentrations of nutrients (especially N and P). There is evidence of slight sediment buildup and organic accumulations. Clarity is between 2 and 4 m, so a mesotrophic lake is usually “swimmable and fishable,” to use a phrase made famous by the Federal Water Pollution Control Act of 1972.

Eutrophic waterbodies (see Figure 4.3) may be dominated by algal growth or by larger plant growth. If algae-dominated, the water may have a green, cloudy appearance from the colonies of algae suspended or floating in the water. If plant-dominated, the submersed macrophytes will decrease the concentrations of the green pigment, chlorophyll, and use much of the nutrient concentrations, making for clearer water. Thus clarity as indicated by Secchi depth readings are higher than if the water body were an algae-dominated eutrophic system. This makes trophic state classification based on appearance very difficult.

Like almost everything in the environment, there is an optimal range between too little and too much nutrient loading. A minimal amount of nutrients is needed in any ecosystem, but when this amount is exceeded, as was the case for Lake Erie some decades ago, algal growth can become prolific. In the right balance, algae serve as food sources and are crucial to energy and mass balances in aquatic systems. Out of balance, however, the algae use up too much of the DO needed by fish and other aquatic organisms. The nutrients find their way into water bodies through numerous avenues, but the major categories are either point sources or nonpoint sources. As the name implies, point sources deliver nutrients and other pollutants to surface waters from a single point, such as a pipe, conduit, outfall structure, or ditch. Non-point pollutants are those that flow over broad expanses, such as runoff from agricultural practices, mining, roads, neighborhoods, and urbanized areas. Another nonpoint source of pollutants is the atmosphere. In fact, atmospheric deposition can be the largest source of many contaminants. The nutrients can take on many physical and chemical properties. For example, nitrogen can be in solid phase, such as in a commercial fertilizer, in liquid phase, such as when ammonia is dissolved in runoff water, or in gas phase, such as when ammonia or nitric acid is found in soil pores. The chemical forms can also be diverse, such as when conditions make for a reduced form, for example, ammonia, or in an oxidized form, such as nitrite or nitrate. Thus, the process of eutrophication includes elevated biological productivity resulting from increased input of nutrients or organic matter into aquatic systems. For lakes, which do not flow as rapidly as streams, such increased biological productivity usually leads to decreased lake volume because organic detritus accumulates. Natural eutrophication continues as aquatic systems fill in with organic matter. This is contrasted with cultural eutrophication, which is exacerbated by human activities and the consequent point and nonpoint pollution.

In retrospect, the death sentence to Lake Erie was premature. The assumptions of the time were that things could not change enough to return biodiversity to the lake ecosystem. Thankfully, these predictions were wrong. However, the Great Lakes are still vulnerable. In fact, some new problems have emerged, whereas others have been solved. To wit, the invasion of opportunistic species that are threatening the diversity of enormous regions; notably the appearance and proliferation of the zebra mussel (Dreissenia polymorpha) throughout much of the Great Lakes (see the discussion in Chapter 6).

6.3.10 Eutrophication

Eutrophication is the process by which a body of water becomes enriched in dissolved nutrients (as phosphates), stimulating the growth of aquatic plant life usually resulting in the depletion of dissolved oxygen.

Table 1.5 lists more specifics on the various categories and thresholds for the DfE assessment.

Table 1.5. DfE Master Criteria Cleaning Productsa [18]

In addition to the main ingredient requirements, the DfE program utilizes various life cycle considerations. Some of these elements include energy usage, nonozone-depleting substances and provide information on environmental, consumer, and worker safety matters. Further inclusions are that it restricts product volatile organic compound (VOC) content based on the most stringent government criteria and does not allow hazardous air pollutants or air toxics, except those that meet the DfE safer ingredient criteria. The program also does not allow products containing chemicals included on EPA’s Toxics Release Inventory chemical list, except those that meet the DfE safer ingredient criteria. Ingredients must not exhibit the characteristic of ignitability and product pH must be ≥ 4 and ≤ 9.5; products with a pH outside this range may be considered for recognition if in vivo testing [18].

1 Introduction

Eutrophication, associated to high nutrient concentrations and recurrent algae blooms, is the most important environmental problem in many lakes and reservoirs. An issue of concern associated with algal blooms is the potential production of toxins by different phytoplankton species within the blooms, which are dangerous for human health (Paerl and Otten, 2013). The implementation of short and long term restoration strategies that contribute to health recovery of water bodies requires deep knowledge of the aquatic system, as well as detailed modelling and optimization (Estrada et al., 2011).

Water resources management must include restoration of water bodies not only affected by point sources (which has been intensively addressed by the construction of water treatment plants), but also those affected by nonpoint nutrient sources (Jeppesen et al., 2012). One approach applied to address the problem of nonpoint nutrient sources for water bodies is the use of artificial wetlands. They are portions of land, covered with macrophytes, through which a water stream is derived, to reduce its nutrient concentration (nitrogen and phosphorus) before being discharged into the water body under study. Many physicochemical processes are involved in the reduction of nutrient concentration within wetlands, such as retention and assimilation by macrophytes, plankton and other microorganisms; sedimentation, adsorption from the sediments, among others (Langergraber et al., 2009). During the last decades, artificial wetlands have become an attractive alternative for water treatment since they have low maintenance cost, have a high efficiency and productivity and present ecological benefits (Reddy et al., 1999). Many lakes and water reservoirs have a positive response to reduced nutrient discharge, while others present a great resistance to improve their trophic condition due to nutrients discharge from sediments, internal recycle of nutrients and, in some cases, the presence of zooplanktivorus fish that cause a reduction on zooplankton population, which can no longer control phytoplankton growth by grazing. In this case, it may become necessary to implement inlake restoration strategies like sediment dreadging, hypolimnetic oxygenation and biomanipulation.

Experimental analysis of restoration actions is time-consuming and monitoring for long periods has large associated costs to implement. The development of ecological water models integrated to optimization strategies can help to propose and evaluate management strategies in both the short and long term (Estrada et al., 2011).

In this work, we propose an integrated mechanistic model for an eutrophic reservoir and artificial wetland within a dynamic optimization framework. Dynamic mass balances have been formulated for the main phytoplankton groups, two zooplankton groups and two size classes of zooplanktivorous fish in the reservoir, as well as dissolved oxygen and main nutrients. A simplified model has been considered for the artificial wetland. Algebraic equations stand for forcing functions profiles, such as temperature, solar radiation, river inflows and concentrations, etc. The complete model is formulated as an optimal control problem with a control vector parameterization approach (gPROMS, PSEnterprise 2014). Optimization variables characterize external reduction of nutrients (fraction of nutrient rich water stream that is derived through an artificial wetland) and biomanipulation strategies (fish removal rate). Numerical results provide optimal profiles for restoration actions. The present study has been carried out on Paso de las Piedras Reservoir, which is the drinking water source for two cities in Argentina.

Europe

In Europe, eutrophication is one of the main water pollution problems, which originates partially from the past European common agricultural policy. The intensive cultivation of land demanded the use of large amounts of fertilizers in a relatively small total land area. Although the situation has improved in the last few years with the phosphorus levels in water being decreased, the presence of nitrates in the aquatic environment is still a problem.

Despite the fact that organic pollution still remains a problem, the steps taken to improve the situation cannot be overlooked. Specifically, the improvement in both wastewater treatment and emission controls has led to a significant decrease in the percentage of heavily polluted rivers, from 24% in the late 1970s to 6% in the 1990s in Western Europe. In contrast, the situation is not exactly the same in the southern member states, since 50% of the population is not yet connected to sewage treatment operations.

Another problem in relation to aquatic receivers in northern and eastern Europe is acidification, whereas elevated concentrations of POPs are found near large European cities and industrialized areas.

Eastern European countries involved in the accession process during the last few years have a lot to achieve in meeting the established water quality criteria set in EU legislation. In the Czech Republic and Slovakia, 57% of the drinking water in 1990 did not meet the quality criteria, whereas 70% of all water may be unacceptable for drinking in Poland. In the Russian Federation, industry, agriculture, and municipal landfills have contributed to the pollution of groundwater in 1400 areas. Moreover, high PCB concentrations have been detected in rivers and the levels of POPs draining into the Arctic may be higher than those found in urban America or Western Europe, in some cases.

Abstract:

Human impacts on coastal waters, through eutrophication and overfishing, associated with the global change phenomenon are leading to a proliferation of both micro- and macroalgae. Algae can settle and develop on a wide range of surfaces including both natural and man-made structures. They are fast colonisers and can out-compete numerous species. The fixation of marine organisms on immersed manmade structures is responsible for major economic costs and the recent recrudescence of algae in the environment might increase the fouling phenomenon observed: the resistance penalty for ships is known to be increased by 11% in presence of a light microalgal slime to 34% in case of colonisation by macroalgae (Schultz, 2007). The paints used nowadays often contain biocides, are non selective against target organisms and are not environmentally friendly. The development of new antifouling paints requires a better understanding of both the mechanisms of fixation and colonisation of the fouler organisms. This chapter focuses on the fixation of algae (both micro and macro), the damages they cause and the method of prevention currently used.

3.3 Water Quality

Reduced inflow to lakes and streams induces eutrophication of the water bodies, a process where water bodies receive excess nutrients that stimulate excessive growth of plankton and zooplankton [28]. Thermal pollution increases evaporation and warmer waters affecting salt balance and harming habitat-forming species such as coral, oysters, and mussels [29]. The projected frequent droughts and the lower stream flows will further adversely affect the quality of the water bodies due to pesticides, pathogens, sediments, dissolved organic carbon as well as emerging pollutants found in the enriched runoff. The water bodies are subjected to these hazardous substances, harming aquatic life and the water quality [30]. The anthropogenic sources of pollutants also contribute to the presence of bioavailable metals causing metal toxicity [31].

The higher concentrations of biodegradable organic material, in terms of biological oxygen demand (BOD) and chemical oxygen demand (COD), may lead to the decomposition of the organic material and excess release of nutrients, such as N and P, to produce dense algal bloom that decreases the dissolve oxygen (DO), causing hypoxia in the water layers.

Eutrophication is a worldwide problem and a large number of lakes are exposed to it, hindering many of their functions including the supply of drinking water, recreation, and as cultural and bird sanctuaries. Excessive production of planktonic algae leads to oxygen deficiency, fish death, reduced biodiversity, and the formation of the periodical nitrogen-fixing bacteria, cyanobacteria. The harmful algal blooms (Cyano-HABs)—blue green algae—emit foul odor and produce toxins that harm the ecological balance, indicating that the lake's natural “buffering capacity” may be in danger [28].

Similarly, groundwater pollution is caused either from saline water that flows laterally into the depleted zone (especially near coasts) or from the deeper layers of water, which are more saline. A good example is the coastal aquifer shared by Israel and the Gaza Strip in which inadequately treated sewage effluent, runoff, fertilizers, and pesticides residues and leachate from landfills and seawater intrusion contribute to very high concentrations of nitrates and chlorides exceeding standard limits for drinking water and causing irreversible damage to some parts of the aquifers [32]. Being a shared aquifer, the discharge of raw sewage from the Gaza Strip flows north easterly along the Mediterranean Sea to the beaches of Israel, endangering the health of Gazans and Israelis alike. Weak regulations and overall low capacity to regulate and enforce those regulations further exacerbates the issue [33].

1.2.1 Nutrient Pollution

The most prevalent water-quality problem is eutrophication, which is the result of enrichment of nutrients in an ecosystem. A significant fraction of high-nutrient loads is phosphorus and nitrogen from urban and farmlands. Large bodies of water were also threatened by eutrophication. World Wildlife Fund reported that in the past century the phosphorus concentration had increased by a factor of 10 in the Baltic Sea (Vandeweerd et al., 2006). A study by the United Nations Environmental Program (UNEP) has indicated that about 40% of the lakes and reservoirs globally have been affected by eutrophication due to nutrient enrichment on coastal hypoxia, creating algal blooms that are harmful to human health (Ricciardi and Rasmussen, 1999). The mechanism of eutrophication is not fully understood, but the two primary nutrients to blame are phosphorus and nitrogen. The levels of nutrients in many lakes and rivers increased significantly over the past 50 years due to increased discharge of domestic wastes and nonpoint pollution from agricultural practices and urban development (Mainstone and Parr, 2002). The impact in water-quality reduction is noticeable in shallow bodies of water that are surrounded by land such as the Baltic Sea, where marine biotopes are threatened by loss of air or reduction in quality from eutrophication, contamination, unregulated fishery activities, and human settlements. By 2000, water-quality degradation in many lakes of industrialized countries stopped or slowed down due to the increased use of wastewater treatment technologies (Schindler, 2012). However, eutrophication of lakes and rivers is on the fast rise in many countries, where there is excessive fertilizer application in agriculture and at places which lack pollution reduction due to economic reasons. More than 80% of sewage in developing countries is discharged untreated, containing everything from human waste, farm waste to highly toxic industrial discharges. The sewage discharges have polluted rivers, lakes, and coastal areas. Both the composition and quantity of nutrients impact the formation of harmful algal blooms (HABs) (Hallegraeff, 2003). HAB may be caused and sustained by exogenous chronic low-level nutrient delivery or by episodic events. Hence, the detection and prediction of HABs and their toxins have become critical for water-quality management.

Pollution of freshwater ecosystems impacts the habitat and quality of aquatic life and other wildlife. The type of contaminants and the levels of contamination determine the suitability of water for many uses such as drinking, bathing, and agriculture. Removing pollutants from water is usually difficult, costly, and often impossible. The impacts of pollution on drinking water sources of small communities are more significant than in larger metropolitan areas, since small towns may not afford expensive treatment technologies. Extreme- or hyper-eutrophication of drinking water sources, for example, Lake Dianchi, and Lake Taihu in China, has resulted in ecological and human health issues. The problem in these lakes was so severe that all the native water plants and many species of fish were killed. Anoxic conditions kill snails in the bottom water. Due to the poor quality of the water, it has been challenging to supply water for domestic use that meets regulatory standards. Many polluting industries such as leather tanning and chemicals manufacturing are moving from developed countries to developing countries. Although there have been some regions that have shown improvements in water quality, water pollution is on the rise globally. The effects of eutrophication in the Florida Everglades are causing a shift in its native flora and fauna. The total phosphorus concentration in Lake Okeechobee was 69 μg/L despite the use of over 17,000 ha of stormwater treatment areas since 2004 (Richardson et al., 2007).

Water contamination from agricultural livestock operations has been a persistent concern. However, the growth of concentrated animal feeding operations (CAFOs) in the past 3 decades presents a greater risk to water quality because of the increased volume of waste and the contaminants in the waste. The manure or sludge from intensified agriculture may leach to surface and groundwater and cause health problems (Richardson et al., 2007; Ruley and Rusch, 2002). CAFOs have been a concern as a “point source” for a variety of potential contaminants. The waste streams contain nutrients, growth hormones, antibiotics, chemicals additives in the manure or in equipment cleaners, pathogens such as Escherichia coli, animal blood, silage leachate from corn feed, or copper sulfate used in footbaths for cows. For example, a large farm with 800,000 pigs may produce over 1.6 million tons of waste a year, which is one and a half times more than the annual sanitary waste produced by the city of Philadelphia, Pennsylvania, a city with a population of more than 1.5 million (Mittal, 2009). Thus, CAFOs require large waste treatment plant next to the operation. Many times, the wastewater is stored in lagoons prior to the treatment. Floods following rains can cause waste storage lagoons to overflow, causing large discharges to nearby water bodies (Field and Struzeski Jr, 1972). Contaminants also travel over land or through surface drainage systems to nearby creeks or through man-made ditches.