Contents

• Introduction
• Background
• What Are Harmful Algal Blooms?
• HAB Types and Impacts
• Factors Contributing to HAB Formation
• Incidence and Trends
• Efforts to Address Harmful Algal Blooms
• Enacted Legislation
• Federal Agency Efforts
• Regulatory Efforts and Guidelines
• HABs, Cyanobacteria, and Cyanotoxins
• Nutrient Management
• Research Gaps
• Legislation in the 115^116th Congress
• Conclusion

Summary

Scientific research indicates that in recent years, the frequency and geographic distribution of harmful algal blooms (HABs) have been increasing nationally and globally. Because the impacts of HABs can be severe and widespread—often with interstate implications—these issues have been a perennial interest for Congress. While algal communities are natural components of healthy aquatic ecosystems, under certain conditions (e.g., increased temperatures and nutrient concentrations), algae may grow excessively, or "bloom," and produce toxins that can harm human health, animals, aquatic ecosystems, and the economy.

In 2014, a cyanobacterial HAB in Lake Erie affected the drinking water for more than 500,000 people in Toledo, Ohio. In 2016, a massive HAB in Florida's Lake Okeechobee negatively impacted tourism and aquatic life. HABs have been recorded in every state and have become a concern nationwide.

Many types of algae can cause HABs in freshwater systems. The most frequent and severe blooms involve the proliferation of cyanobacteria. Some cyanobacteria species can produce toxins—cyanotoxins—that can cause mild to severe health effects in humans and kill aquatic life and other animals.

HABs can also contribute to deteriorating water quality and ecosystem health. As masses of cyanobacteria or other algae die and decompose, they consume oxygen, sometimes forming "dead zones" where life cannot survive. These areas can kill fish and organisms, such as crabs and clams, and have detrimental economic effects.

Scientists widely consider nutrient enrichment to be a key cause of HAB formation. While nutrients are essential to plants and natural parts of aquatic ecosystems, excessive amounts can overstimulate algal growth. Sources include point sources (e.g., municipal wastewater discharges) and nonpoint sources (e.g., fertilizer runoff from agricultural and urban areas).

Congress, federal agencies, and states have taken steps to address HABs and nutrients that contribute to their occurrence. The Harmful Algal Bloom and Hypoxia Research and Control Act of 1998 (HABHRCA), as amended, established an interagency task force, required the task force to prepare reports and plans addressing marine and freshwater HABs, and authorized funding for research, education, monitoring activities, etc.

In December 2016June 2019, the Environmental Protection Agency (EPA) used its authority under the Clean Water Act (CWA) to proposepublish final water quality criteria for two algal toxins in waters used for recreational purposes. States usemay consider such criteria when developing water quality standards—measures that describe the desired condition or level of protection of a water body and what is needed for protection.

Alternatively, they may use these values as the basis of swimming advisories for public notification purposes at recreational waters.

Further, EPA has emphasized the need to reduce nutrient pollution from all sources to reduce public health and environmental impacts associated with HABs. The CWA does not authorize EPA to regulate all sources. It authorizes EPA to regulate point (direct) sources of nutrients but does not authorize EPA to regulate nonpoint (diffuse) sources of nutrient pollution.

Some states have developed guidelines for algal toxins, primarily for use in guiding swimming advisories. Also, states have listed waters as impaired, or not meeting water quality standards, for algal blooms or algal toxins. Some of these states have begun to develop Total Maximum Daily Loads (TMDLs)—essentially pollution budgets—to address them. Most states have identified nutrient-related pollution as a priority to be addressed by their TMDLs and/or alternative restoration plans. States rely heavily on financial assistance from EPA in implementing these plans and, more broadly, in addressing nonpoint source pollution that leads to degraded water quality and HAB formation. Congress has long provided financial assistance through EPA for regional, state, and local programs through CWA Sections 106 and 319 planning grants, geographic programs (such as the Chesapeake Bay and Great Lakes), and other sources. The President's FY2019FY2020 budget request for most of these programs is either eliminated or significantly reduced.

Congress continues to show interest in addressing HABs. This interest has largely focused on funding research to close research gaps identified by scientists and decisionmakers and to coordinate the efforts of federal agencies and their partners to study and address HABs.

---

Introduction

Scientific research indicates that in recent years, the frequency and geographic distribution of harmful algal blooms (HABs) have been increasing nationally and globally.¹ HABs can be detrimental to human health, animals, aquatic ecosystems, and local economies. In 2014, a major HAB in Lake Erie caused the city of Toledo, Ohio, to issue a "do not drink" order for tap water that left more than 500,000 people without drinking water for two days and had an estimated impact of $65 million in lost benefits.² In the summer of 2016, a massive HAB in Lake Okeechobee—Florida's largest freshwater lake—resulted in beach closures, losses to the tourism industry, and negative impacts on marine life. According to the U.S. Environmental Protection Agency (EPA), between January 1June 2 and August 12, 20161, 2017, states reported at least 266281 notices for freshwater HABs, including cautions, warnings, public health advisories, and public health warnings.

³

Congress, many federal agencies, states, localities, and other partners have taken and continue to take steps to address the rising trend in HABs and their impacts. However, there are many gaps in current scientific understanding of HABs among the research and management communities and considerable debate as to how best to address the issue from a regulatory standpoint. This report explores these issues as they pertain to HABs in freshwater systems. Specifically, it addresses the conditions and activities that contribute to the occurrence of freshwater HABs; steps that Congress, federal agencies—particularly EPA—and their partners are taking to address and mitigate their occurrence; and the current knowledge gaps on this issue. This report is focused on freshwater HABs, not marine or coastal HABs or issues associated with HABs in drinking water supplies.³4

Background

What Are Harmful Algal Blooms?

Algal communities are naturally occurring components of healthy aquatic ecosystems, such as lakes, rivers, and estuaries. However, under certain environmental conditions, such as increased temperatures and nutrient concentrations (e.g., nitrogen and phosphorus), colonies of algae can grow excessively, or "bloom," and produce toxins that pose a threat to human and aquatic ecosystem health and potentially cause economic damage. These HABs sometimes produce discolorations in the water that can appear as scums, paint-like slicks, clotted mats, or foam that may vary in color (i.e., light to dark green, yellow, red, or brown). Even when visible signs of a bloom are absent, however, algal toxins may still cause harmful effects.⁴5 Figure 1 shows an aerial view of a HAB that produced visible green scums in Lake Okeechobee, Florida, in July 2016.

Figure 1. Aerial view of a July 2016 Harmful Algal Bloom in Lake Okeechobee, Florida

Source: USGS, https://www.usgs.gov/news/science-harmful-algae-blooms.

HAB Types and Impacts

While many types of algae can cause HABs in bodies of freshwater, cyanobacteria (sometimes referred to as blue-green algae) typically cause the most frequent and severe blooms.⁵6 Cyanobacterial HABs pose a threat to human and aquatic ecosystem health and can kill pets, livestock, and wildlife. Some species of cyanobacteria produce toxins, called cyanotoxins, which can cause hepatic (liver-related), neurologic, respiratory, dermatologic, and other symptoms.⁶7 These may be acute or chronic, mild or severe, and in some cases may be fatal. Humans may be exposed to cyanotoxins by consuming tainted drinking water, fish, or shellfish; swimming or recreating in waters with certain concentrations of cyanotoxins present; or inhaling aerosolized toxins.⁷8 The cyanotoxins associated with these HABs can contaminate fish, interfere with a variety of recreational activities, and cause other economic and environmental damages.

There are many types of cyanotoxins, which may have multiple variants with a wide range of toxicities.⁸9 The most commonly occurring and most studied cyanotoxin is microcystin.⁹

10

Although cyanobacterial HABs are considered to be the most prevalent and toxic types of HABs, blooms of "golden algae" (Prymnesium parvum) are an emerging problem and likely the most problematic of non-cyanobacterial freshwater HAB taxa (i.e., group of related organisms classified as a unit).¹⁰11 Golden algal HABs have caused large fish kills worldwide, including millions of fish in Texas. Most of the major fish kills have occurred since 2000. Golden algae thrive in brackish water, such as the rivers and reservoirs found in areas of Texas, Oklahoma, and Wyoming. The toxins produced by golden algae target gill-breathing organisms, such as fish, clams, and mussels. According to information from two states that experience golden algal blooms, there is currently no evidence that golden algal toxins pose a direct threat to humans, other mammals, or birds.¹¹12 Effects of cyanobacterial HABs and golden algae HABs are detailed in Table 1.

In addition to the effects of algal toxins on human and animal health, HABs can also contribute to deteriorating water quality and ecosystem health. An overabundance of cyanobacteria or other algae can block out sunlight and clog fish gills. In addition, as the algae die and decompose, they consume oxygen, leaving waterways in a hypoxic (or low oxygen) state, sometimes forming "dead zones"—areas where life cannot survive due to lack of oxygen. Low oxygen areas can suffocate and kill fish and bottom-dwelling organisms such as crabs and clams. According to EPA, over 166 dead zones have been documented nationwide, including in waterbodies such as the Chesapeake Bay and the Gulf of Mexico.¹²13 Significant economic losses have occurred as a result of hypoxia.¹³

14

Factors Contributing to HAB Formation

Many factors may influence the occurrence and prevalence of HABs in freshwater, including nutrient concentrations, water temperature, availability of light, pH, and water circulation. Nutrient enrichment is widely recognized as one of the key causes of HAB formation.¹⁴15 Nutrients, such as nitrogen and phosphorus, are essential to plant growth and natural parts of aquatic ecosystems. However, when high levels of nutrients enter a body of water, they stimulate plant and algal growth, which can lead to depletion of dissolved oxygen (as explained above), reduced transparency (i.e., turbidity), changes to the biological community (e.g., loss of sportfish, such as bass), and degradation of the aesthetic appeal of the water (i.e., from odor and scums). This process is called eutrophication.¹⁵16

While some sources of nutrients in water bodies are natural, many anthropogenic activities contribute nutrients to waterbodies from a number of point and nonpoint sources. Point sources include municipal and industrial wastewater discharges and concentrated animal feeding operations (CAFOs).¹⁶17 Nonpoint sources include urban stormwater runoff, failing septic systems, atmospheric deposition of nitrogen from fossil fuel emissions, runoff from fertilized cropland, and manure runoff from cropland, pastures, and animal feeding operations. See Table 2 for more information on these sources.

Studies also indicate that increased temperatures and changes in frequency and intensity of rainfall associated with climate change may also favor HAB formation.¹⁷18 HABs generally proliferate in warmer waters. In addition, some studies have found that swings between flooding and drought may enhance HAB formation. For example, if intense rainfall is followed by a drought, the nutrients washed into receiving water bodies may remain in them longer, increasing the potential for HABs.¹⁸19

Incidence and Trends

Scientists largely agree that the frequency and distribution of HABs, the economic losses from them, the types of resources affected, and the number of toxins and toxic species have all increased in recent years.¹⁹20 Some scientists note that factors such as better detection methods and increased reporting have contributed to the upward trend. HABs, including cyanobacterial HABs, have been recorded in the waters of all 50 states, with some HABs crossing state lines.²⁰21 Figure 2 shows the generalized distribution of selected freshwater HAB events (cyanobacterial HABs and golden algal HABs) that took place between 2006 and 2015 across the United States.

The findings of EPA's most recent national assessment of lakes²¹22 are consistent with other reports of the rising trend in HABs. In EPA's 2012 National Lake Assessment, EPA concluded that there was little change from its 2007 survey of lakes, with two exceptions—trends in algal toxin and nutrient measures.²²23 In 2012, EPA and its partners detected microcystin in 39% of lakes, a 9.5% increase from 2007.²³24 EPA noted, however, that for both studies, the concentrations of microcystin remained low and rarely exceeded the levels of concern established by the World Health Organization (WHO) for recreational uses (see "Regulatory Efforts and Guidelines"). EPA also found an 8.3% increase in the percentage of lakes in the "most disturbed condition" category when analyzing the density of cyanobacterial cells (i.e., an indicator of risk for exposure to algal toxins because the cells may produce toxins).²⁴25 Finally, EPA found an overall increase in the median concentration of phosphorus across all lakes²⁵26 and a "dramatic" decline (18.2%) in the percentage of lakes with low nutrients and high oxygen levels.²⁶27 These findings are important because in many lakes, phosphorus is considered the limiting nutrient, meaning that the available quantity of this nutrient controls the pace of algal production. It also means that even small increases in phosphorus can lead to very rapid increases in algal growth.²⁷28 More broadly, the study found that nutrient pollution is a widespread problem across the country. Approximately 35% of lakes have excessive levels of total nitrogen, and 40% of lakes have excessive levels of total phosphorus.²⁸29

Figure 2. Generalized Distribution of Selected Freshwater Harmful Algal Blooms (HABs) in the United States

SourcesSources: Graphic adapted from a National Office of Harmful Algal Blooms at Woods Hole Oceanographic Institution map of HABs that occurred between 2006 and 2015 (available at http://whoi.edu/redtide/regions/us-distribution) and an EPA adaptation of the map that reflects input from HAB experts with broad experience in HAB events and reports to the U.S. National Office for Harmful Algal Blooms (see EPA, Draft Human Health Recreational Ambient Water Quality Criteria or Swimming Advisories for Microcystins and Cylindrospermopsin, EPA 822-P-16-002, December 2016, p. 4). Notes: Each state that has experienced one or more cyanobacterial HABs or golden algal HABs is indicated with a single dot. Larger green ovals mark areas where more widespread cyanobacterial HAB problems occurred.

Efforts to Address Harmful Algal Blooms

Enacted Legislation

Congress has recognized the increasing frequency of HABs and has passed legislation in an effort to address public health, economic, and environmental consequences of HABs. In 1998, Congress passed the Harmful Algal Bloom and Hypoxia Research and Control Act (HABHRCA), which established an Interagency Task Force on Harmful Algal Blooms and Hypoxia.²⁹30 It required the task force to prepare reports assessing HABs and hypoxia with a focus on coastal waters and authorized funding for HAB and hypoxia-related research, education, and monitoring activities. The Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) chaired the task force. In 2004, Congress reauthorized HABHRCA and expanded it to include assessments of HABs in freshwater.³⁰31 In 2014, Congress again reauthorized HABHRCA and established a national HAB/ and Hypoxia Program to be maintained by NOAA through the task force.³¹32 It identified NOAA and EPA as the lead federal agencies for marine and freshwater aspects of the program, respectively, and required additional reports and a comprehensive research plan and action strategy.

Congress most recently reauthorized HABHRCA in January 2019 through the Harmful Algal Bloom and Hypoxia Research and Control Amendments Act of 2017, included within the National Integrated Drought Information System Reauthorization Act of 2018 (P.L. 115-423). The HABHRCA amendments require the task force to submit a scientific assessment of HABs in U.S. coastal and freshwater systems once every five years to Congress, require NOAA to develop and maintain a public website that provides information on HAB and Hypoxia Program activities, and added a section that authorizes NOAA or EPA to determine that a hypoxia or HAB event is an event of national significance (for marine and freshwater systems, respectively). If an event is designated, the legislation authorizes NOAA or EPA to make funds available to the affected state or locality to assess and mitigate the detrimental environmental, economic, subsistence use, and public health effects of the event.

In 2015, in response to public safety concerns arising from the Toledo, Ohio, HAB event, Congress passed legislation addressing algal toxins in drinking water. The Drinking Water Protection Act amended the Safe Drinking Water Act to require EPA to develop a strategic plan to assess and manage the risks associated with algal toxins in public drinking water supplies.³²33

The following year, Congress included a provision in the Water Infrastructure Improvements for the Nation (WIIN) Act that required EPA to designate a Harmful Algal Bloom Coordinator to coordinate projects and activities under the Great Lakes Restoration Initiative involving HABs in the Great Lakes.³³34 Table 3 provides a list and description of the HAB-specific legislation enacted since 1998.

In addition to HAB-specific legislation, the Clean Water Act (CWA) authorizes EPA to address water quality concerns associated with HABs.³⁴35 The act establishes a system, under Section 303, for states to adopt ambient water quality standards consisting of the designated use or uses of a water body (e.g., recreational, public water supply, or aquatic life) and the water quality criteria that are necessary to protect the use or uses.³⁵36 States then use their water quality standards to determine which waters must be cleaned up, how much effluent may be discharged, and what is needed for protection.

Section 304(a) requires the EPA Administrator to publish and, from time to time, revise water quality criteria that accurately reflect the latest scientific knowledge on the kind and extent of all identifiable effects on human health and the environment that might be expected from the presence of pollutants.³⁶37 These criteria constitute guidance that states use in adopting their water quality standards. As recognized by Section 510 of the CWA,³⁷38 states may develop water quality standards that are more stringent than required by EPA regulations. EPA's water quality standards regulations³⁸39 require that in developing water quality standards, states must adopt water quality criteria that protect the designated use. States are to establish numerical criteria—based on (1) EPA's recommended criteria, (2) EPA's criteria modified to reflect site-specific conditions, or (3) other scientifically defensible methods—and establish narrative criteria or criteria based on biomonitoring methods where numerical criteria cannot be established or to supplement numerical criteria.

Section 303(d) of the CWA requires states to identify waters that are impaired by pollution, even after application of pollution controls.³⁹40 For those waters, states must establish a Total Maximum Daily Load (TMDL) of pollutants to ensure that water quality standards can be attained. A TMDL is a quantitative assessment of pollution sources and pollutant reductions needed to restore and protect U.S. waters; it is also a planning process for attaining water quality standards. TMDLs may address all pollution sources, including point sources, such as municipal sewage treatment or industrial plant discharges, and nonpoint sources such as urban runoff and agricultural runoff.

Also, Section 118 of the CWA provides that the United States should seek to attain the goals embodied in the Great Lakes Water Quality Agreement of 1978, as amended by the Water Quality Agreement of 1987 and any other agreements and amendments.⁴⁰41 It tasks EPA to take the lead in the effort to meet the agreement's goals, working with other federal agencies, states, and localities. As seen in the text box, the most recent amendment includes a HAB-related goal.

Federal Agency Efforts

Many federal agencies are involved in carrying out various HAB-related activities, including conducting HAB research, monitoring algal toxins and water quality, forecasting HABs, supporting projects to improve water quality, and facilitating community outreach efforts. Some in Congress, however, have expressed concern about the activities and expenditures of various agencies and potential redundancies. In the Drinking Water Protection Act (P.L. 114-45), enacted August 7, 2015, Congress directed the Government Accountability Office (GAO) to inventory funds expended by federal agencies to examine toxin-producing cyanobacteria and algae or address public health concerns related to harmful algal blooms. GAO was to recommend ways to improve interagency coordination and reduce duplication of efforts. According to the 2016 GAO report that responded to the mandate, 17 agencies conducted research, monitoring, response, or other HAB-related activities between FY2013 and FY2015.⁴²43 The GAO report provides detailed information on federal agencies' key HAB-related activities, expenditures, and specific statutory authorities, and, thus, this report will not discuss these in detail. Rather, this section identifies the federal agencies involved in a key interagency effort and highlights actions EPA specifically is taking in its role as the leader of freshwater HAB issues.

As previously mentioned, HABHRCA established an interagency task force that is charged with

• promoting a national strategy to help communities understand, predict, control, and mitigate freshwater and marine HAB and hypoxia events;
• enhancing, coordinating, and assessing the activities of existing HABs and hypoxia programs; and
• providing for development of a comprehensive research plan and action strategy.

Table 4 provides a list of the federal agencies and organizations specifically required in HABHRCA to participate on the task force. The reauthorization of HABHRCA in 2014 reconstituted the task force as the Interagency Working Group on the Harmful Algal Bloom and Hypoxia Research and Control Act (IWG-HABHRCA), responsible for maintaining a national HAB/hypoxia program. NOAA and EPA share primary responsibility under HABHRCA for administering the national HAB and hypoxia program, with NOAA leading marine aspects of the program and EPA in charge of freshwater aspects. In addition to agencies listed in the table, the U.S. Army Corps of Engineers is an active member in the IWG-HABHRCA.⁴³

In its role under HABHRCA and the CWA, EPA's efforts to address HABs include coordinating the efforts of multiple entities, developing regulations and guidelines to protect water quality (see "Regulatory Efforts and Guidelines" section), conducting research, providing financial assistance through grants and other agreements, and educating the public.⁴⁴ In its coordination role, EPA leads, chairs, or cochairs several working groups or task forces, including the IWG-HABHRCA, the Inland HAB Discussion Group, the Great Lakes Interagency Task Force, and the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force (Hypoxia Task Force). See Table 5 for a description of these efforts.

EPA has also conducted internal research on HABs and their toxins focused on water quality (including how different factors such as nutrients, light, temperature, etc., affect HAB occurrence and toxicity), human and ecological health effects, monitoring and analytical methods research, and drinking water treatment research.⁴⁵ The agency also provides research grants, such as those provided through the Science to Achieve Results (STAR) program, focused on topic areas including the prediction, prevention, control, and mitigation of freshwater HABs and the fate and effects from less-common emerging HABs.⁴⁶

EPA also provides financial assistance to states, tribes, and others to address water pollution, including nonpoint source pollution. Examples of such assistance include nonpoint source implementation grants under CWA Section 319, capitalization grants under the Clean Water State Revolving Fund, and grants under CWA Section 106, which are provided to states, interstate agencies, and tribes to administer programs that prevent, reduce, and eliminate water pollution.

Regulatory Efforts and Guidelines

EPA and states have also taken steps to address HABs and nutrient loads that contribute to their proliferation through regulatory efforts and guidelines. This section focuses on regulatory efforts and guidelines related to EPA's authorities under the CWA and specifically excludes efforts under the Safe Drinking Water Act.

HABs, Cyanobacteria, and Cyanotoxins

EPA, the World Health Organization (WHO)WHO, and many states have developed guidelines for cyanotoxins in recreational waters.⁴⁷ These guidelines are summarized in Table 6 and discussed below.

EPA Guidelines

In December 2016, EPA issued draft recreational water quality criteria or swimming advisories for microcystins and cylindrospermopsin for public comment.⁴⁸ According to EPA, these criteria reflectreflected the concentrations of two cyanotoxins that would be protective of human health in recreational waters used for swimming or other activities: 4 µg/L for microcystin and 8 µg/L for cylindrospermopsin.⁴⁹ EPA suggestssuggested that states maycould consider using the proposed values when determining whether to post swimming advisories in recreational waters and maycould consider using the same values when adopting new or revised water quality standards.

Many entities—including states, representatives of publicly owned treatment works,⁵⁰ agricultural organizations, and environmental groups—provided comments on the draft criteria:⁵¹

• Some commenters, including states, were supportive of the criteria for purposes of informing swimming advisory decisions but did not support the use of the criteria for developing water quality standards, noting, among other concerns, that cyanotoxins are not a pollutant discharged into waterways but rather result from other pollutants (nutrients) entering waterways and other factors. Environmental groups generally supported EPA's criteria for use in both swimming advisories and development of water quality standards.
• Commenters' opinions varied regarding the proposed concentrations of microcystin and cylindrospermopsin in the draft criteria. Some states felt the levels were appropriate, environmental groups felt they should be more stringent, and other states suggested they are overly protective, particularly when compared to the WHO guideline for microcystin.

Many commenters—particularly states, publicly owned treatment works, and agricultural groups—expressed a number of implementation concerns. One key concern raised was that these criteria, if used for water quality standards, would improperly regulate response organisms rather than a discharged pollutant. Some argued that algal toxins are not a pollutant that CWA permittees discharge. Rather, the discharge of other pollutants, such as excess nutrients, may lead to HAB formation. In its draft criteria document, EPA explained that it does not anticipate states using the criteria alone for permitting purposes, recognizing that cyanobacteria and their toxins are not typically present in permitted discharges. EPA goes on to say the following:

Permits are more likely to be written to address point source discharges of the causal pollutants, such as nutrients, on a waterbody-specific or watershed basis, where the permit writer has determined there is a reasonable potential for the causal pollutants in the discharge to cause or contribute to an exceedance of the cyanotoxin standards.⁵²

In this regard, some commenters expressed concern that it is not known precisely what level of nutrients will result in a bloom, nor is it understood what factors will trigger the release of toxins. Several commenters suggested that EPA explore these issues further before moving forward with water quality criteria for purposes other than guiding advisory levels for swimming.

Many commenters also expressed implementation concerns regarding monitoring and sampling. According to the Association of Clean Water Administrators⁵³ many states do not currently have mechanisms in place to adequately sample for the levels of the toxins specified by EPA or lack adequate lab capacity to process increased samples. Some states, publicly owned treatment works, and agricultural groups also commented that the variability of HABs within a body of water and over even short spans of time can make sampling and analysis complicated, particularly when using the data to determine if a water body is impaired. The commenters urged EPA to address these issues in detail before moving forward with the criteria.

In June 2019, EPA announced the final recommended recreational water quality criteria or swimming advisories for microcystins and cylindrospermopsin.⁵⁴ EPA's recommended concentrations in recreational waters protective of human health while swimming or participating in primary contact recreational activities on the water are 8 µg/L for microcystin and 15 µg/L for cylindrospermopsin. In the Federal Register notice announcing the release of the criteria, EPA noted that, in response to public comments, the agency did not apply a relative source contribution term in deriving the final criteria.⁵⁵ Additionally, EPA stated that the primary factor for the change in recommended values was an updated ingestion rate, which reflected a study published in 2017.⁵⁶

WHO Guidelines

In 2003, WHO proposed guideline values for protection from adverse health outcomes associated with cyanobacteria blooms in fresh water used for recreational purposes.⁵⁴57 The guidelines are defined at three levels: low, moderate, and high probability of adverse health effects. WHO concluded that a single guideline value was not appropriate because "it is necessary to differentiate between the chiefly irritative symptoms caused by unknown cyanobacterial substances and the potentially more severe hazard of exposure to high concentrations of known cyanotoxins, particularly microcystins." Table 6 shows the WHO guideline levels for microcystin.⁵⁵

58

State Guidelines

According to EPA documents, approximately 3035 states have implemented cyanobacterial HAB guidelines for recreational waterways as of November 2015March 2018. Some of these states use qualitative guidelines only (i.e., visual inspection for blooms rather than quantitative detection methods) or quantitative guidelines for cyanobacterial cell density rather than guidelines for the specific cyanotoxins.

Of the 3035 states that have implemented cyanobacterial HAB guidelines, 2124 have established numeric guidelines for microcystin or cylindrospermopsin. The levels and associated actions vary considerably among states (see Table 6). California has adopted the strictest concentrations for both cyanotoxins (0.8 µg/L for microcystin and 41 µg/L for cylindrospermopsin). Several states have adopted the WHO value of 20 µg/L for microcystin. Only sevenTen states have adopted quantitative guidelines for cylindrospermopsin.

Some states have also added waters affected by algal blooms and algal toxins to their impaired water lists (i.e., Section 303(d) lists) for algal blooms and algal toxins. According to data from EPA's Assessment and Total Maximum Daily Load Tracking and Implementation System, 2430 states have listed waters as impaired for algal blooms, and twothree states—California, Iowa, and New Hampshire—have listed waters as impaired for algal toxins (see Table 7). California has listed only one of its watersand Iowa have listed six and one of their waters, respectively, as impaired for algal toxins and hasbut have not yet developed a TMDLTMDLs. New Hampshire has listed 6680 of its waters as impaired for algal toxins and has developed one TMDL that covers two waters.⁵⁶ The New Hampshire TMDL establishes a total phosphorus loading target that, if met, is expected to achieve state water quality criteria and thresholds for dissolved oxygen, chlorophyll a (an indicator of algae), and cyanobacteria.⁵⁷

17 TMDLs.⁵⁹ The New Hampshire TMDLs use nutrients, namely phosphorus, as a surrogate for cyanobacteria (as well as for some other nutrient-associated parameters such as chlorophyll A and dissolved oxygen in some cases).⁶⁰ They establish a total phosphorus loading target that, if met, is expected to achieve state water quality criteria and thresholds for cyanobacteria (as well as for other nutrient associated parameters, such as chlorophyll A, for some of the TMDLs).

Nutrient Management

Scientists and policymakers widely recognize the need to reduce nutrient inputs to aquatic systems to limit eutrophication and proliferation of HABs. According to EPA, nitrogen and phosphorus pollution is one of the most serious and pervasive water quality problems in the United States.⁵⁸61 While EPA and states have worked to address nutrient pollution for over a decade, many observers believe more progress is needed to reduce the threat to water quality and public health. EPA has acknowledged that without greater progress, "the successes to date will likely be outpaced by the rapidly increasing population and the resulting increase in the rate and impact of nitrogen and phosphorus pollution."⁵⁹

62

According to EPA, as of 2016, 45 states identified nutrient-related pollution as a priority to be addressed by TMDLs and/or alternative restoration plans in setting long-term priorities for their CWA Section 303(d) programs.⁶⁰ To date63 As of May 2016, more than 8,600 nutrient-related TMDLs havehad been established, primarily by states, to guide nutrient reduction efforts in more than 5,800 waterbodies.⁶¹64

In 2016, EPA issued a memorandum with a renewed call to states and stakeholders to intensify their efforts, in collaboration with EPA, to reduce nutrient pollution.⁶²65 The memorandum emphasized EPA's support for state planning or implementation of watershed-based, multistakeholder projects to reduce the impacts to public health from nitrogen and phosphorus pollution contributing to HABs. EPA listed and described key elements of its plans for working with partners and stakeholders over the next several years, including prioritizing watersheds and setting load reduction goals, developing numeric nutrient criteria, reducing point sources of nutrient pollution, reducing nutrient loads from nonpoint sources, and providing financial and technical assistance.

For almost two decades, EPA has expressed support for developing numeric criteria for nutrients. In a memorandum issued in 2011, EPA stated that "it has long been EPA's position that numeric criteria targeted at different categories of water bodies and informed by scientific understanding of the relationship between nutrient loadings and water quality impairment are ultimately necessary for effective state programs."⁶³66 To this end, EPA has provided 30 states with technical assistance for numeric nutrient criteria development through its Nutrient Scientific Technical Exchange Partnership and Support Program.⁶⁴ To date67 As of 2018, 23 states havehad adopted numeric criteria into their water quality standards for nitrogen and/or phosphorus for at least one of their water bodies.⁶⁵68 In 2013, EPA outlined barriers to numeric nutrient criteria implementation and actions to help states address them.⁶⁶69 The barriers included, among other things, an inability to reduce nonpoint source loads of nitrogen and phosphorus and problems implementing water-quality-based limits.

EPA has also emphasized the need to focus on reducing nutrients from all sources—both point and nonpoint sources.⁶⁷70 Under the CWA, EPA has authority to regulate discharges from point sources.⁶⁸71 However, the CWA does not authorize EPA to regulate nonpoint sources. EPA can influence activities of nonpoint sources only through use of grants and funding—such as CWA Section 319, which addresses nonpoint source pollution through state-run nonpoint pollution management programs—and related technical assistance.⁶⁹72 Through such programs, states may, for example, ask farmers or ranchers to use alternative methods in their operations to prevent fertilizers from reaching streams and may provide funds to help them install on-farm pollution management systems or practices. In its document addressing barriers to numeric nutrient criteria, EPA proposed actions to address them, including continuing to collaborate with the U.S. Department of Agriculture to leverage resources for conservation practices⁷⁰73 and to better quantify the environmental results of best management practices and other efforts, continuing to implement the Section 319 grant program, and addressing the challenges of manure management by working with large animal growers and poultry integrators to develop sustainability agreements and practices that reduce nutrient pollution.⁷¹74

Some observers argue that the voluntary nature of controlling nonpoint sources is a key challenge in developing and implementing TMDLs, a primary tool that states are employing to address nutrient pollution. Farming and forestry groups have long been concerned about how their activities might be addressed in TMDLs and whether they might be subject to CWA regulation of some sort, even though the act does not provide EPA with regulatory authority over nonpoint sources. Municipalities and industries contend that regulating only point sources imposes disproportionate requirements on their operations, especially in waters that are impaired both by point and nonpoint sources.

Federal Financial Assistance

Recognizing that a critical role for EPA in addressing nutrient pollution is supporting watershed-based efforts at the state and local level, in its 2016 memorandum, the agency stated that the Office of Water would continue to provide financial assistance to states through CWA Section 106 and Section 319 grant programs and the Clean Water State Revolving Fund (CWSRF) Program, as well as Section 604(b) planning grants,⁷²75 Wetland Program Development grants, and grants targeted toward specific geographic locations, such as the Chesapeake Bay, Great Lakes, and other water bodies. The President's FY2019FY2020 budget request for EPA proposes that funding for these programs, with the exception of the CWSRF, be eliminated or significantly reduced (see Table 8).⁷³76 The proportion of funds provided to nonpoint source pollution projects through the CWSRF program is relatively minor compared to the amount provided to publicly owned treatment works for infrastructure projects. As reported by EPA, 96% of the cumulative assistance provided through the CWSRF as of 2016 has been provided to publicly owned treatment works; only 4% was provided to nonpoint source pollution projects and National Estuary Program projects.⁷⁴77 It is unclear how, considering EPA's long-standing emphasis on using these programs to address nonpoint source pollution, the FY2019 budget would support the goals of the agency in its efforts to reduce nutrient pollution, and ultimately reduce the occurrence and frequency of HABs.

Table 8 presents a comparison of the President's FY2019 budget request with the FY2016-FY2018 enacted appropriations for selected grants and programs referenced above that include funding support for addressing nonpoint source pollution. These grants and programs are funded within the EPA State and Tribal Assistance Grants and the Environmental Programs and Management appropriations accounts.

Research Gaps

In addition to the challenges of reducing nutrient pollution contributing to HABs, scientists widely recognize key research gaps that hinder the ability to prevent, predict, minimize, and suppress HABs. In reauthorizing HABHRCA in 2014, as discussed above, Congress directed NOAA—through the IWG-HABHRCA—to prepare a comprehensive research plan and action strategy to address marine and freshwater harmful algal blooms and hypoxia. The February 2016 task force report⁷⁵78 includes a discussion of the key challenges in HAB and hypoxia management and discusses the many gaps in the research and management communities' knowledge of HAB and hypoxia events. Federal agencies—including USGS,⁷⁶79 EPA,⁷⁷80 and NOAA⁷⁸81—and research efforts sponsored by these agencies cite similar gaps and areas needing continuing research. The following text box summarizes some of these key research areas.

Legislation in the 115^116th Congress

Congressional interest in freshwater HABs has largely focused on funding further research, improving monitoring of HABs, and coordinating the efforts of federal agencies and their partners to study and address HABs. In the 115^th Congress, the Senate passed S. 1057, which would, among other things, reauthorize HABHRCA for FY2019-FY2023, add the Army Corps of Engineers to the interagency task force, and allow the administrators of NOAA (marine) or EPA (freshwater) to declare a HAB or hypoxia event as an event of "national significance." Such a determination would prompt authority for the administrators to provide funding to the affected state or local government. A related bill, H.R. 4417, has been introduced in the House.

The Senate also passed S. 129, which would reauthorize the National Sea Grant Program and make funds available for HAB research through that program. The bill would authorize grants for university research on several targeted topics, including "the biology, prevention, and forecasting of harmful algal blooms." A related bill, H.R. 4306, has been introduced in the House.

The Great Lakes and Fresh Water Algal Bloom Information Act (H.R. 1893) in the 115^th Congress would require NOAA to create an electronic database of research and information on the causes of, and corrective actions being taken with regard to, algal blooms in the Great Lakes, their tributaries, and other surface fresh waters and for other purposes.

H.R. 3661 would establish a program to award prizes for the development of innovative, environmentally safe solutions for reducing, mitigating, and controlling harmful algal blooms and for other purposes.

Three bills have been introduced that would seek to address issues specific to Lake Okeechobee and the Florida Everglades:

• H.R. 2137 seeks to address concerns arising from the HAB outbreak that occurred in Lake Okeechobee, FL, during the summer of 2016. Record rainfalls and an impending hurricane season prompted the U.S. Army Corps of Engineers to release water from the lake into rivers and estuaries in an attempt to keep the lake from overflowing. The releases occurred at a time when a lake-wide HAB was forming, allowing nutrients and algae to move downstream,⁷⁹ eventually reaching area beaches and requiring beach closures and cleanups that had substantial impacts on the local and state economy. Florida's governor requested a federal state of emergency declaration, which the Federal Emergency Management Agency denied because it determined that supplemental federal assistance under the Robert T. Stafford Disaster Relief and Emergency Assistance Act⁸⁰ was not considered appropriate for the event.⁸¹ H.R. 2137 would direct the President to treat a harmful algal bloom "caused by certain activities of the Federal Government" as an emergency for the purposes of the Stafford Act.
• H.R. 3665 would require the IWG-HABHRCA to prepare an assessment and a plan for reducing, mitigating, and controlling HABs and hypoxia in the Greater Everglades region, similar to what the working group has completed at a national level and for the Great Lakes region.
• H.R. 6645 would—similar to S. 1057 and H.R. 4417—reauthorize HABHRCA but would also, like H.R. 3665, require an assessment and action plan for the Everglades region.

HAB-related bills introduced in the 116^th Congress include the following:

• S. 10 and H.R. 335, companion bills, would require the IWG-HABHRCA to prepare an assessment and a plan for reducing, mitigating, and controlling HABs and hypoxia in south Florida, similar to what the working group has completed at a national level and for the Great Lakes region.
• H.R. 414 would amend the Robert T. Stafford Disaster Relief and Emergency Assistance Act⁸² to include algal blooms in the definition of major disaster.
• H.Amdt. 284—included in the House-passed version of the Labor, Health and Human Services, Education, Defense, State, Foreign Operations, and Energy and Water Development Appropriations Act, 2020—would redirect $6.25 million in funding for the National Institute of Environmental Health Sciences under the National Institutes of Health in order to support research into the impact of red tide and other HABs on human health.
• S. 910 and H.R. 2405 would reauthorize and amend the National Sea Grant College Program Act, which would continue to make funds available for HAB research through competitive grants.
• S. 914 would amend the Integrated Coastal and Ocean Observation System Act of 2009. Specific to HABs, the bill would add, as a purpose of the system, a focus on monitoring and modeling "changes in the oceans and Great Lakes, including with respect to chemistry, harmful algal blooms, hypoxia, water levels, and other phenomena."
• H.R. 3297 would amend HABHRCA to clarify that during a lapse in appropriations, certain services relating to the HAB Operational Forecasting System are excepted services under the Anti-Deficiency Act.
• H.R. 3324 would, among other things, require the Army Corps of Engineers to modify operations of projects in central and south Florida to ensure that "public health" overlays all authorized project purposes. The bill defines public health to include managing Lake Okeechobee and the central and southern Florida system in a way that minimizes HABs and prevents discharges containing cyanobacteria and their toxins into the St. Lucie and Caloosahatchee watersheds, among other goals.

Conclusion

Recent HAB events highlight the public health, economic, and environmental consequences that communities in the United States may continue to experience, perhaps on a more frequent basis. EPA, NOAA, and other federal agencies are working together to conduct important HAB-related research in an effort to close the gaps in the scientific and management community's understanding of how best to prevent, predict, minimize, and suppress HABs. EPA, states, and their partners are working to identify and restore waterbodies that are affected by HABs and the excess nutrients that contribute to their formation. Congress has passed legislation to help drive and fund research efforts and improve collaboration among the many federal agencies involved in HAB-related activities. Moving forward, Congress may be interested in oversight of the Administration's efforts to implement HABHRCA and other HAB-related authorities. While Congress, federal agencies, and states are taking steps to address HABs, many observers assert that further action is needed to make progress that outpaces the growing consequences of nutrient pollution.

Most observers agree that further research is needed to understand the most appropriate way to predict, minimize, and suppress HAB outbreaks, including whether and how to regulate algal toxins. These advocates assert that Congress should ensure that adequate funding is available for such research. To control HABs, some advocate for regulation of nonpoint source pollution, arguing that point sources are disproportionately regulated and that nonpoint sources are the larger contributors to nutrient pollution. Instead of regulation, some argue that EPA and other federal agencies should continue to focus on collaborative, voluntary watershed-level efforts to address nonpoint source pollution that contributes to HAB formation and that Congress should ensure that financial assistance for these efforts continues.

Controlling nonpoint sources of excess nutrients that contribute to HAB formation is challenging. They are diffuse and pervasive and often attributable to many sources and activities rather than a single cause. Yet, scientists generally agree that the current trends in overenriched waters and HAB events cannot be corrected without addressing nonpoint source nutrient pollution in a significant way and that controlling point sources alone is not enough. Given the consequences of HABs and the difficulty in controlling nonpoint sources of the nutrients that contribute to their formation, challenges and issues associated with HABs are likely to remain of interest to Congress.

Author Contact Information

Footnotes

For a discussion of algal toxins in drinking water, see CRS In Focus IF10269, , Algal Toxins in Drinking Water: EPA Health Advisories, by [author name scrubbed], by Mary Tiemann.

WHO, Guidelines for Safe Recreational Water.

1.	NOAA, State of the Science Fact Sheet—Harmful Algal Blooms, September 2016, http://nrc.noaa.gov/CouncilProducts/ScienceFactSheets.aspx; U.S. Environmental Protection Agency, "Causes and Prevention," https://www.epa.gov/nutrient-policy-data/causes-and-prevention; National Office for Harmful Algal Blooms at Woods Hole Oceanographic Institution, "Recent Trends: National Changes," July 11, 2016, https://www.whoi.edu/redtide/regions/us/recent-trends. C. B. Lopez et al., Scientific Assessment of Freshwater Harmful Algal Blooms, Interagency Working Group on Harmful Algal Blooms, Hypoxia, and Human Health of the Joint Subcommittee on Ocean Science and Technology, 2008, p. 1. .
2.	M. Bingham, S. K. Sinha, and F. Lupi et al., Economic Benefits of Reducing Harmful Algal Blooms in Lake Erie, Environmental Consulting and Technology, Inc., submitted to the International Joint Commission, October 2015.
3.	EPA, Recommended Human Health Recreational Ambient Water Quality Criteria or Swimming Advisories for Microcystins and Cylindrospermopsin, May 2019, https://www.epa.gov/sites/production/files/2019-05/documents/hh-rec-criteria-habs-document-2019.pdf.	4.
45.	Lopez et al., Scientific Assessment, p. 1 of Freshwater Harmful Algal Blooms.
56.	J. L. Graham, N. M. Dubrovsky, and S. M. Eberts et al., Cyanobacterial Harmful Algal Blooms and U.S. Geological Survey Science Capabilities, U.S. Geological Survey Report 2016-1174, 2016, pp. 1-2. , 2016.
67.	Centers for Disease Control and Prevention, "Harmful Algal Bloom (HAB)-Associated Illness," https://www.cdc.gov/habs/illness-symptoms-freshwater.html.
78.	See footnote 5Graham et al., Cyanobacterial Harmful Algal Blooms.
89.	See footnote 5Graham et al., Cyanobacterial Harmful Algal Blooms.
910.	See footnote 5 and Keith A. Loftin, Jennifer L. Graham, and Elizabeth D. HilbornGraham et al., Cyanobacterial Harmful Algal Blooms; and Keith A. Loftin et al., "Cyanotoxins in Inland Lakes of the United States: Occurrence and Potential Recreational Health Risks in the EPA National Lakes Assessment 2007," Harmful Algae, vol. 56 (2016), pp. 77-90. Other common cyanotoxins that can have adverse environmental health effects include anatoxins, cylindrospermopsins, and saxitoxins.
1011.	National Office for Harmful Algal Blooms at Woods Hole Oceanographic Institution, "Golden Algae," July 11, 2016, https://www.whoi.edu/redtide/impacts/freshwater/golden-algae.
1112.	Texas Parks and Wildlife, Texas Commission on Environmental Quality, and U.S. Fish and Wildlife Service, "Texas Golden Alga Facts," http://www.tceq.texas.gov/publications/gi/gi-378.html/at_download/file; Arizona Game and Fish Department, "Golden Alga Frequently Asked Questions," http://www.azgfd.gov/temp/golden_alga_faqs.shtml.
1213.	EPA, "Nutrient Pollution, The Effects: Environment," https://www.epa.gov/nutrientpollution/effects-environment.
1314.	National Science and Technology Council, Committee on Environment and Natural Resources, An Assessment of Coastal Hypoxia and Eutrophication in U.S. Waters, November 2003, pp. 22-23.
1415.	See footnote 5 and footnote 4, p. 12Graham et al., Cyanobacterial Harmful Algal Blooms; and Lopez et al., Scientific Assessment of Freshwater Harmful Algal Blooms.
1516.	EPA, "Preventing Eutrophication: Scientific Support for Dual Nutrient Criteria," February 2015, https://www.epa.gov/sites/production/files/documents/nandpfactsheet.pdf.
1617.	CAFOs are point sources, as defined by CWA Section 502(14). CAFOs are agricultural operations where animals are kept and raised in confined situations that meet criteria established in EPA's CAFO regulation (40 C.F.R. 122.23). These criteria include specific numbers of confined animals and designation as a significant contributor of pollutants.
1718.	H. W. Paerl and J. Huisman, "Climate Change: A Catalyst for Global Expansion of Harmful Cyanobacterial Blooms," Environmental Microbiology Reports, vol. 1, no. 1 (February 2009), pp. 27-37.; National Science and Technology Council, Subcommittee on Ocean Science and Technology, Harmful Algal Blooms and Hypoxia Comprehensive Research Plan and Action Strategy: An Interagency Report, Interagency Working Group on the Harmful Algal Bloom and Hypoxia Research and Control Act, February 11, 2016, p. 12. Jerry M. Melillo, Terese Richmond, and Gary W. Yohe; Jerry M. Melillo et al., Climate Change Impacts in the United States: The Third National Climate Assessment, U.S. Global Change Research Program, October 2014, pp. 79, 198, 216.
1819.	Paerl and Huisman, "Climate Change," pp. 27-37.
1920.	See footnote 1.
2021.	National Office for Harmful Algal Blooms at Woods Hole Oceanographic Institution, "Distribution of HABs in the U.S.," August 15, 2016, https://www.whoi.edu/redtide/regions/us-distribution.
2122.	EPA, National Lakes Assessment 2012: A Collaborative Survey of Lakes in the United States, EPA 841-R-16-113, December 2016. Every five years, EPA and its partners sample more than 1,000 lakes to inform the agency's National Lakes Assessment, a statistically based assessment of the biological, chemical, physical, and recreational condition of the nation's lakes.
2223.	Ibid.EPA, National Lakes Assessment 2012, pp. 1-2.
2324.	Ibid.EPA, National Lakes Assessment 2012, pp. 1, 18.
2425.	Ibid.EPA, National Lakes Assessment 2012, p. 28. Note that according to the assessment, 15% of lakes are in the most disturbed condition using cyanobacteria cell counts as an indicator of risk for exposure to algal toxins.
2526.	Ibid.EPA, National Lakes Assessment 2012, p. 2, 13. The median concentration of phosphorus increased from 20 µg/L in 2007 to 37 µg/L in 2012.
2627.	Ibid.EPA, National Lakes Assessment 2012, pp. 2, 13. In 2012, EPA found 18.2% fewer oligotrophic lakes (i.e., lakes with low nutrients and high oxygen levels) than in 2007.
2728.	Ibid.EPA, National Lakes Assessment 2012, p. 12.
2829.	The terms total nitrogen and total phosphorus include all forms of the nutrient in the sample. For example, total phosphorus includes a measurement of orthophosphate, condensed phosphate, and organic phosphate.
2930.	P.L. 105-383.
3031.	P.L. 108-456.
3132.	P.L. 113-124.
3233.	P.L. 114-45.
3334.	P.L. 114-322.
3435.	Clean Water Act, as amended (33 U.S.C. §1251 et seq.)
3536.	33 U.S.C. §1313.
3637.	33 U.S.C. §1314.
3738.	33 U.S.C. §1370.
3839.	40 CFR 131.
3940.	33 U.S.C. §1313.
4041.	33 U.S.C. §1269. In 1987 amendments to the CWA (P.L. 100-4) Congress affirmed the goals of the amended Great Lakes Water Quality Agreement of 1978.
4142.	Great Lakes Water Quality Agreement, U.S.-Canada, as amended, September, 7, 2012.
4243.	GAO, Environmental Protection: Information on Federal Agencies' Expenditures and Coordination Related to Harmful Algae, GAO-17-119, October 2016, p. 5. Note that GAO identified 17 agencies that have conducted research, monitoring, or other HAB-related activities in FY2013-FY2015. However, the report focuses on 12 federal agencies whose data was sufficiently reliable for the purposes of the report.
43.	National Science and Technology Council, Subcommittee on Ocean Science and Technology, Harmful Algal Blooms and Hypoxia Comprehensive Research Plan and Action Strategy: An Interagency Report, Interagency Working Group on the Harmful Algal Bloom and Hypoxia Research and Control Act, February 11, 2016.
44.	Education efforts include communication and outreach, such as newsletters and videos, to increase public awareness regarding the adverse effects of nutrient pollution and HABs.
45.	See footnote 42, p. 35GAO, Environmental Protection: Information on Federal Agencies' Expenditures and Coordination Related to Harmful Algae, GAO-17-119, October 2016.
46.	EPA "Freshwater Harmful Algal Blooms," Funding Opportunity Announcement Number EPA-G2017-STAR-A1, Office of Research and Development, October 28, 2016.
47.	EPA has also developed recommended levels for drinking water for microcystin and cylindrospermopsin through health advisories. See CRS In Focus IF10269, Algal Toxins in Drinking Water: EPA Health Advisories, by [author name scrubbed]Mary Tiemann.
48.	As discussed above, CWA Section 304(a) directs EPA to develop and publish and, from time to time, revise criteria for water quality that accurately reflect the latest scientific knowledge. EPA, "Request for Scientific Views: Draft Human Health Recreational Ambient Water Quality Criteria and/or Swimming Advisories for Microcystins and Cylindrospermopsin," 81 Federal Register 91929-91931, December 19, 2016. Note this comment period was extended. See EPA, "Extension of Public Comment Period: Draft Human Health Recreational Ambient Water Quality Criteria and/or Swimming Advisories for Microcystins and Cylindrospermopsin," 82 Federal Register 10766-10767, February 15, 2017.
49.	EPA, Draft Human Health Recreational Ambient Water Quality Criteria or Swimming Advisories for Microcystins and Cylindrospermopsin, EPA 822-P-16-002, December 2016, p. 1.
50.	The National Association of Clean Water Agencies, which represents the interests of publicly owned treatment works (i.e., municipal wastewater treatment facilities), provided comments on behalf of its members.
51.	Comments discussed in this section are available in Docket ID No. EPA-HQ-OW-2016-0715, available at https://www.regulations.gov/docket?D=EPA-HQ-OW-2016-0715.
52.	See footnote 49EPA, Draft Human Health Recreational Ambient Water Quality Criteria or Swimming Advisories for Microcystins and Cylindrospermopsin.
53.	The Association of Clean Water Administrators is a nonpartisan, national organization of state, interstate, and territorial water program managers who implement CWA programs.
54.	EPA, "Recommended Human Health Recreational Ambient Water Quality Criteria or Swimming Advisories for Microcystins and Cylindrospermopsin," 84 Federal Register 26413, June 6, 2019.
55.	In calculating water quality criteria, EPA uses a relative source contribution to allow a percentage of the exposure to a contaminant to include other potential sources. For the recreational water quality criteria for microcystin and cylindrospermopsin, EPA assumed that all cyanotoxins exposure is from incidental exposure of water while recreating and therefore did not apply a relative source contribution.
56.	EPA, "Recommended Human Health Recreational Ambient Water Quality Criteria or Swimming Advisories for Microcystins and Cylindrospermopsin," 84 Federal Register 26413, June 6, 2019.
57.	WHO, Guidelines for Safe Recreational Water Environments: Volume 1, Coastal and Fresh Waters, 2003.
5558.	WHO also established guidance values for cyanobacteria and chlorophyll-a.
5659.	According to information provided in New Hampshire's TMDLa TMDL for Phillips Pond in Sandown, NH, lakes were listed as impaired for swimming if surface blooms or "scums" of cyanobacteria were present—even if present only along a downwind shore. AECOM, New Hampshire Department of Environmental Services, Final Total Maximum Daily Load for Pearly Lake, Rindge, NH, prepared for EPA Region 1, August 2014, p. 2-5Phosphorus for Phillips Pond, Sandown, NH, September 2018, p. 1-1, https://www.des.nh.gov/organization/commissioner/pip/publications/documents/r-wd-18-11.pdf.
5760.	Ibid, p. 1-1.
58New Hampshire Department of Environmental Services, Final Total Maximum Daily Load for Phosphorus for Phillips Pond, Sandown, NH. See also New Hampshire Department of Environmental Services, Total Maximum Daily Load for Hunkins Pond, Sanbornton, NH, January 2011, p. 1-1, https://www.des.nh.gov/organization/divisions/water/wmb/tmdl/documents/hunkins-pond.pdf. 61.	EPA, Office of Water, FY2016-2017 National Water Program Guidance, EPA 420-R-15-008, April 2015, p. 15.
5962.	EPA, Office of Water, Actions to Help States Address Barriers to Numeric Nutrient Criteria Implementation, EPA 820-F-13-011, August 2013.
6063.	Joel Beauvais, Deputy Assistant Administrator, EPA, memorandum to State Environmental Commissioners, State Water Directors, "Renewed Call to Action to Reduce Nutrient Pollution and Support for Incremental Actions to Protect Water Quality and Public Health," September 22, 2016, https://www.epa.gov/nutrient-policy-data/working-partnership-states-address-phosphorus-and-nitrogen-pollution-throughrenewed-call-action-reduce-nutrient-pollution-and-support-incremental-actions.
6164.	Ibid., p. 4.Beauvais, "Renewed Call to Action to Reduce Nutrient Pollution." EPA has approved approximately 7074,000 TMDLs in total since 1995 to address impairments from many different pollutant types. See https://ofmpub.epa.gov/waters10/attains_nation_cy.control#tmdls_by_state.
6265.	See footnote 60. Beauvais, "Renewed Call to Action to Reduce Nutrient Pollution."
6366.	Nancy K. Stoner, Acting Assistant Administrator, EPA, memorandum to Regional Administrators, Regions 1-10, "Working in Partnership with States to Address Phosphorus and Nitrogen Pollution through Use of a Framework for State Nutrient Reductions," March 16, 2011, https://www.epa.gov/nutrient-policy-data/working-partnership-states-address-phosphorus-and-nitrogen-pollution-through.
6467.	See footnote 60. Beauvais, "Renewed Call to Action to Reduce Nutrient Pollution."
6568.	EPA, "State Progress Toward Developing Numeric Nutrient Water Quality Criteria for Nitrogen and Phosphorus," https://www.epa.gov/nutrient-policy-data/state-progress-toward-developing-numeric-nutrient-water-quality-criteria. Only oneAccessed August 14, 2019. Website last updated May 2, 2018. One state (Hawaii) and three territories have adopted numeric criteria for nitrogen and phosphorus for all applicable water types (lakes/reservoirs, rivers/streams, estuaries).
6669.	See footnote 59EPA, Actions to Help States Address Barriers.
6770.	See footnote 60. Beauvais, "Renewed Call to Action to Reduce Nutrient Pollution."
6871.	CWA §402; 33 U.S.C. §1342.
6972.	While the 319 program is voluntary at the federal level, states may include regulatory components in their 319 programs.
7073.	A number of U.S. Department of Agriculture agencies provide support through education, outreach, and research, while federal funds are provided through conservation programs to help agricultural producers adopt best management practices for nutrient reduction. Examples of such programs include the Environmental Quality Incentives Program and the Conservation Stewardship Program. For more information see CRS Report R43919, Nutrients in Agricultural Production: A Water Quality Overview, by [author name scrubbed]Megan Stubbs.
7174.	See footnote 59EPA, Actions to Help States Address Barriers.
7275.	CWA Section 604(b) requires states to reserve a small portion of each its CWSRF allotment each fiscal year—1% for most states—to carry out planning under CWA Sections 205(j) and 303(e). States generally use Section 604(b) grants to fund regional comprehensive water quality management planning activities to improve local water quality.
7376.	EPA, Fiscal Year 2018 Justification of Appropriation Estimates for the Committee on Appropriations, EPA-190-K-17-002, May 2017, pp. 114, 456-457.
7477.	EPA, 2016 Annual Report – Clean Water State Revolving Fund Programs, 2016, https://www.epa.gov/sites/production/files/2017-03/documents/2016_cwsrf_annual_report.pdf.
7578.	See footnote 43National Science and Technology Council, Subcommittee on Ocean Science and Technology, Harmful Algal Blooms and Hypoxia Comprehensive Research Plan and Action Strategy.
7679.	See footnote 5. Graham et al., Cyanobacterial Harmful Algal Blooms.
7780.	Lesley V. D'Anglada, EPA, "Editorial on the Special Issue 'Harmful Algal Blooms (HABs) and Public Health: Progress and Current Challenges,'" Toxins, vol. 7 (October 2015), pp. 4437-4441. Also, EPA's solicitation for grant proposals regarding HABs lists specific research gaps the applications should address. EPA "Freshwater Harmful Algal Blooms," Funding Opportunity Announcement Number EPA-G2017-STAR-A1, Office of Research and Development, October 28, 2016.
7881.	NOAA, State of the Science Fact Sheet—Harmful Algal Blooms, September 2016, http://nrc.noaa.gov/CouncilProducts/ScienceFactSheets.aspx.
79.	Florida Sea Grant, "Florida Sea Grant Funds Research on Massive Algae Bloom on Lake Okeechobee," July 21, 2016, https://www.flseagrant.org/news/2016/07/florida-sea-grant-responds-massive-algae-bloom-lake-okeechobee/.
8082.	42 U.S.C. §5121 et seq. et seq.
81.	Letter from W. Craig Fugate, Administrator, Federal Emergency Management Agency, U.S. Department of Homeland Security, to Rick Scott, Governor of Florida, July 15, 2016.