National Park Service 

U.S. Department of the Interior 

Natural Resource Program Center 

Scope of Contaminants of Emerging Concern 

in National Parks 

Natural Resource Report NPS/NRPC/NRR—2008/032 
ON THE COVER

Rainbow over Upper Falls of the Yellowstone River, Yellowstone National Park, WY 

Photograph by: Rebecca A. Landewe (2007)
Scope of Contaminants of Emerging Concern 

in National Parks

Natural Resource Report NPS/NRPC/NRR—2008/032 

Rebecca A. Landewe* 

On detail to the Water Resources Division, Summer 2007 

National Park Service 

Natural Resource Program Center 

1201 Oakridge Drive, Suite 150 

Fort Collins, CO 80525 

*Permanent Address: 

Environmental Protection Agency – Region 7 

Water, Wetlands, and Pesticides Division 

901 N. Fifth Street 

Kansas City, KS 66101 

August 2008 

U.S. Department of the Interior 

National Park Service 

Natural Resource Program Center 

Fort Collins, Colorado
The Natural Resource Publication series addresses natural resource topics that are of interest and 

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Views, statements, findings, conclusions, recommendations, and data in this report are solely 

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internet or by sending a request to the address on the back cover. 

Please cite this publication as: 

Landewe, R. A. 2008. Scope of contaminants of emerging concern in National Parks. Natural 

Resource Report NPS/NRPC/NRR—2008/032. National Park Service, Fort Collins, Colorado. 

NPS D-1965, August 2008

ii
Contents 

Page 

Figures ........................................................................................................................................... iv 

List of Acronyms ........................................................................................................................... v 

Executive Summary...................................................................................................................... vii 

Acknowledgements .....................................................................................................................viii 

Introduction .................................................................................................................................... 1 

Effects of Contaminants of Emerging Concern in the Environment .............................................. 3 

Sources of Contaminants of Emerging Concern ............................................................................ 3 

Preventing EC Contamination ....................................................................................................... 7 

Extent of ECs in National Parks .................................................................................................... 8 

Pacific West Region ............................................................................................................. 9 

Intermountain Region ........................................................................................................ 10 

Southeast Region ............................................................................................................... 10 

Midwest Region.................................................................................................................. 11 

Northeast Region ............................................................................................................... 11 

Alaska Region .................................................................................................................... 11 

Regional and National Studies ........................................................................................... 11 

Future Research Needs ................................................................................................................ 15 

Literature Cited ............................................................................................................................ 17 

iii
Figures

Page 

Figure 1. Map of National Park Service regions and locations where research 

has been conducted in National Park Service units... ......................................................................8 

Figure 2. Parks labeled are in the vicinity of a USGS monitoring site included 

in Kolpin et al. (2002) study on organic wastewater contaminants...............................................12 

Figure 3. Map of largest National Park units identified by Rattner et al. (2005) 

as lacking ecotoxicological data. ...................................................................................................13 

Figure 4. Map of largest National Park units identified by Rattner et al. (2005) 

as being located in watersheds with “more serious water quality problems,” 

with a “high vulnerability to pollution,” and lacking data.............................................................14 

iv
List of Acronyms 

EC emerging contaminants 

EDC endocrine disrupting compounds 

EPA Environmental Protection Agency 

NPS National Park Service 

NB National Battlefield 

NHP National Historical Park 

NHS National Historic Site 

NL National Lakeshore 

NM National Monument 

NP National Park 

NRA National Recreation Area 

NRRA National River and Recreation Area 

NS National Seashore 

OWC organic wastewater contaminants 

PPCP pharmaceuticals and personal care products 

USGS U.S. Geological Survey 

WWTF wastewater treatment facility 

v
vi
Executive Summary 

One of the fundamental purposes of the National Park Service is to conserve the natural state of 

National Parks such that they remain unimpaired for future generations. In recent years, a 

number of studies have reported that a group of compounds broadly categorized as contaminants 

of emerging concern can be found in many National Parks across the country. The presence of 

these emerging compounds of concern in urban and remote areas of National Parks raises several 

questions regarding the extent of contamination, the potential environmental impact, and how 

they might influence the ability of the National Park Service to fulfill its mission. There is a 

growing national interest among the scientific community to ascertain the sources, transport, 

fate, and environmental effects of contaminants of emerging concern, such as pharmaceuticals, 

personal care products, and endocrine disruptors. There are numerous studies documenting 

emerging contaminants below wastewater treatment facilities, a few articles that suggest human, 

natural, or aerial transport into remote and mountainous regions, and a growing body of research 

identifying some of the impacts of these compounds on aquatic communities. Additional 

research is also being conducted on identifying methods to reduce or remove emerging 

contaminants in municipal wastewater treatment plants. While the existing literature on emerging 

contaminants provides a significant amount of insight, overall, there is still a need for a deeper 

understanding on the transport, fate, and metabolic impacts of contaminants of emerging concern 

in the environment. Studies and research in National Parks have been primarily limited to areas 

that receive treated domestic sewage; however, there is evidence that remote environments in 

parks contain emerging contaminants of concern. This review summarizes the state of the current 

knowledge on emerging contaminants, identifies specific studies that have occurred in or near 

National Parks, and highlights areas identified by researchers as needing additional investigation. 

The current body of research leaves several unanswered questions regarding emerging 

contaminants and National Parks, which are suitable for a focused and well-designed 

servicewide research project to address the source and transport of these compounds into 

relatively pristine and sensitive aquatic ecosystems. After gaining a better understanding of the 

presence and effect of emerging contaminants on National Park resources, managers can begin to 

develop management plans that consider these compounds. The result of a servicewide research 

project could help in assessing threats to vulnerable areas and inform the development of 

measures to reduce or remove sources of contamination. 

vii
viii

Acknowledgements 

Thank you to Gary Rosenlieb for his helpful direction during this project. Thank you to Roy 

Irwin, Steve Goodbred, and Brenda Groskinsky for their thoughtful contributions. 
Introduction 

Purpose and Objectives 

The National Park Service (NPS) manages units across the country that are exposed to a myriad 

of potential sources of contaminants of emerging concern (ECs). To date, some effort has been 

focused on detecting, quantifying, and assessing the threat of ECs in NPS units. The goals of this 

review are to summarize what is currently known about ECs in National Parks, with specific 

focus on endocrine disrupting compounds (EDCs), and to identify areas where additional 

attention may be needed. 

Defining Contaminants of Emerging Concern 

In the May 2007 issue of Water Resources Impact magazine, Battaglin et al. define contaminants 

of emerging concern as “any synthetic or naturally occurring chemical or any microorganism 

that is not commonly monitored in the environment but has been recently detected in the 

environment” (Battaglin et al. 2007). These compounds may not themselves be emerging, but the 

concern about the environmental impact of these compounds, some of which have been in 

existence for quite some time, is emerging. As noted in a paper by Daughton (2003), the term 

“emerging” refers to old pollutants with new concerns and new pollutants with unknown issues. 

Other researchers use several different terms and acronyms to identify the numerous compounds 

that can be broadly described as contaminants of emerging concern. While there may be nuances 

in how each author defines the terms emerging contaminants, emerging contaminants of concern, 

and contaminants of emerging concern, they are often used synonymously and interchangeably. 

For the purposes of this review, the acronym EC will be used to generally represent new or 

existing compounds with emerging concerns. 

There are two other categories also used to refer to many of the same compounds captured under 

the broader EC definition: 

Pharmaceuticals and Personal Care Products (PPCPs)

Pharmaceuticals and personal care products are often lumped together in a subcategory of 

ECs. Because pharmaceuticals are designed to be biologically available and 

physiologically active in small doses, very low concentrations could potentially have 

significant effects on the aquatic environment. The Environmental Protection Agency 

(EPA) is focusing research efforts on PPCPs and has a website devoted to summarizing 

the issues (www.epa.gov/ppcp). 

Endocrine Disrupting Compounds (EDCs)

Some ECs and PPCPs are suspected of having effects on the endocrine system. These 

endocrine disrupting compounds have come under intense scrutiny because extremely 

small doses that may be undetectable by common sampling methods could have 

significant effects on the reproduction, growth, and development of organisms. However, 

not all ECs and PPCPs are endocrine disruptors. There are many unanswered questions 

1
about EDCs, including what concentrations are biologically relevant and the effects of 

complex mixtures. 

The widespread use of ECs for personal, agricultural, and industrial purposes has resulted in a 

ubiquitous presence of these compounds in the environment. Researchers have documented the 

ability of many ECs, notably including many PPCPs and EDCs, to pass through wastewater 

treatment facilities (WWTFs) and enter the aquatic environment (Kolpin et al. 2002). The 

literature also documents the presence of ECs in rural watersheds–where pesticides, hormones, 

and antibiotics are used in plant and animal agriculture–and in remote watersheds where some 

ECs migrate via atmospheric transport and deposition (Daly and Wania 2005; Daly et al. 2007). 

As scientists better understand how ECs disperse in the environment, others are identifying 

additional compounds of concern. The growing list of ECs makes the problem of linking cause 

and effect more difficult in field studies where, unlike the controlled laboratory environment, 

there may be complex mixtures of ECs and numerous confounding factors. Despite these 

difficulties and complexities, the scientific community along with government agencies is 

working hard to better understand the transport, fate, and effects of these compounds in the 

environment.

2 
Effects of Contaminants of Emerging Concern 

in the Environment 

The fate of ECs in the environment and how they impact aquatic biota is not well-understood, 

though recent research findings are continually adding to the cumulative body of knowledge. 

Some scientists have focused on compound-specific research on the distribution and impact of 

ECs. For example, several studies have attested to the ubiquity of perfluorinated compounds in 

the environment, documented their accumulation in tissues and organs, and identified impacts on 

hormonal function as an area for additional research (Giesy and Kannan 2002; Oakes et al. 

2005). EPA’s ECOTOX database (www.epa.gov/ecotox/) is one tool scientists can use to search 

for publications on chemical-specific toxicological effects on terrestrial and aquatic life. Building 

upon the research focused on specific compounds, others have evaluated the endocrine 

disrupting properties of the chemical mixtures found in the environment. In effluent from a 

WWTF, one would expect to find not just one but many ECs that could have additive or 

synergistic effects. Scientists recently presented data documenting the significant changes that 

the mixture of endocrine disruptors present in WWTF effluent can have on the sex ratios of fish 

(Vajda et al. 2007) and bullfrog populations (Propper et al. 2007). 

In addition to direct impacts on sexual development, there is evidence that EDCs can have 

indirect or behavioral impacts on aquatic life. Propper et al. (2007) found that the pesticide 

endosulfan impacts the ability of amphibians to produce and detect pheromones. The ability of 

fathead minnows exposed to environmentally relevant concentrations of estrogenic compounds 

were not as successful in competing with unexposed males for females and spawning sites 

(Schoenfuss et al. 2007). While not a direct impact on the gonadal differentiation, these research 

findings suggest that such changes could result in negative impacts on reproductive fitness. 

 

Sources of Contaminants of Emerging Concern 

ECs can come from point sources, such as in a municipal wastewater discharge, or nonpoint 

sources, like leaking septic systems and runoff from agricultural land or urban areas. Each source 

is most likely discharging multiple types of ECs, and for each EC there may be numerous 

potential sources. Additionally, each compound may breakdown into a suite of degradates or 

metabolites, most of which have unknown fates or effects in the environment. 

Wastewater Treatment Facilities and Septic Systems 

Wastewater treatment facilities are a frequent source of ECs, PPCPs, and EDCs. Kolpin et al. 

(2002) conducted a landmark study of organic wastewater contaminants (OWCs) that included 

pesticides, PPCPs, and industrial chemicals. In this national study, the U.S. Geological Survey 

(USGS) evaluated streams from 139 monitoring locations in 30 states for OWCs and found that 

80% contained one or more OWCs. Of all the classes of compounds that were analyzed, steroids, 

detergent metabolites, and plasticizers made up about 80% of the total concentration. 

Nonprescription drugs were more frequently detected than antibiotics, hormones, and other 

prescription drugs. Approximately 35% of the compounds are suspected of being endocrine 

disruptors. While the individual concentrations of the OWCs may have been small, the combined 

3 
effect of these endocrine disruptors is potentially significant. The authors cited research showing 

that exposure to low levels (<0.001 ug/L) of some hormones can have significant effects on 

aquatic life. Given this data and other research on the presence of ECs in WWTF effluent, it is 

reasonable to assume that most, if not all, National Parks that have a WWTF discharge or are 

downstream of a domestic WWTF have ECs in their waterways, to which aquatic biota are being 

exposed and potentially affected. Septic systems, although more dispersed in a watershed, can 

also contribute PPCPs to the environment through nonpoint source runoff from the drain field. 

Biosolids 

Biosolids, a byproduct of the wastewater treatment process, are another potentially significant 

pathway for transport of ECs into the environment. According to one national survey (NEBRA 

2007), approximately half of the biosolids produced in the United States are land applied and 

thus have the potential to enter waterways via surface runoff. Kinney et al. (2006) analyzed 

biosolids from municipal wastewater treatment plants and found a total of 55 OWCs in the nine 

samples taken from seven states, with a minimum of 30 found in each sample. The authors 

concluded “that biosolids are highly enriched in OWCs (as mass-normalized concentrations) 

when compared to effluent or effluent-impacted water.” There are two known National Parks 

that may be impacted by the use of biosolids. Spectacle Island, part of Boston Harbor Islands 

National Recreation Area, was capped with 65,000 cubic yards of biosolids as part of the effort 

to convert the landfill to a recreation area. Additional research may be warranted to determine 

whether the biosolids cap could be a potential source of ECs to the underlying groundwater or 

into Boston Harbor. Grant-Kohrs Ranch National Historic Site accepts biosolids and, as such, 

may be introducing a source of ECs into the park. 

Agricultural Land Uses 

Research indicates that several common pesticides used in row crop agriculture have endocrine 

disrupting properties and are introduced into the local aquatic environment through stormwater 

runoff or to more remote watersheds through air transport and deposition. One report from the 

USGS National Water Quality Assessment Program, which assessed ten years of sampling data 

from sites across the U.S., provides clear documentation that agricultural pesticides run off into 

local waterways (Gilliom 2006). Other research, which will be discussed in greater detail below, 

indicates that atmospheric transport has resulted in the wide distribution of pesticides in remote 

watersheds (Blais 2005, Daly et al. 2007, Hageman et al. 2006, WACAP 2004). Parks that have 

agricultural uses within their watershed or airshed, or that use pesticides in their resource 

management, may be at risk of finding ECs in their waterways. 

Pharmaceuticals (e.g., hormones and antibiotics) used in livestock operations and confined 

animal feeding operations can travel to local waterways through nonpoint source runoff. Meyer 

et al. (2004) found frequent detections of antibiotics, including chlortetracycline, sulfamethazine, 

and lincomycin, in wastewater lagoons at swine feeding operations, which indicates that these 

compounds can either resist degradation or revert back to the parent compound after being 

excreted. Natural steroid hormones and hormones used for veterinary purposes (e.g., growth 

hormone, birth control) have also been found in agricultural watersheds and they may impact 

aquatic life. Hutchins et al. (2003) found significant concentrations of natural estrogens in 

4 
wastewater lagoons at swine feeding operations. In a separate study, Hutchins et al. (2007) found 

evidence to suggest the concentration of these estrogens significantly decreases with subsequent 

treatment stages, indicating that the level of treatment undergone by the land applied manure 

could significantly affect the concentrations of estrogens that could run off into local waterways. 

This information is important for park managers to consider if their resource management plans 

include the land application of manure from animal feeding operations. 

Industry 

Industrial manufacturing may also be a source of ECs and, as such, may be of concern to those 

parks downstream of industrial WWTF discharges. Examples of ECs that are suspected 

endocrine disruptors include perfluorinated compounds, phthalates found in plasticizers, and 

surfactants such as nonylphenol. Perchlorate, a component of rocket fuel, is one industrial 

compound utilized by the U.S. Department of Defense (DoD) that is suspected of having 

endocrine disrupting effects on the thyroid system. The DoD has used perchlorate as a solid 

propellant since the 1940s and currently uses it in 14% of munitions (DoD 2007). Although the 

DoD currently has strict procedures to prevent releases, historical handling practices of the 

compounds resulted in releases to the environment, like at Lake Mead National Recreational 

Area, Nevada. The DoD Materials of Evolving Regulatory Interest Team (MERIT) placed 

perchlorate on their Action List to develop risk management options (DoD 2007). 

Natural Sources 

In addition to anthropogenically created ECs and potential EDCs, there are natural sources of 

these compounds in the environment. Pulp mill effluents release significant quantities of natural 

phytoestrogens from plant material, including β-siterosterol (which has been shown to be 

estrogenic in fish) (Tremblay and Van der Kraak 1998). In addition to the production of 

perchlorate for use in rocket fuel and munitions as noted above, scientists have documented 

perchlorate as naturally occurring in the arid western regions of the United States (Rajagopalan 

et al. 2006). Plants, wildlife, and livestock (Kolodziej and Sedlak 2007) contribute natural steroid 

hormones to waterways, which could potentially have endocrine-disrupting effects on aquatic 

life. The waterways in parks with grazing wildlife, cattle, horseback riding, or unmanaged 

populations of feral pigs, goats, or horses may be at risk of EC contamination through nonpoint 

source runoff or direct deposition into water bodies. Unfortunately, the background 

concentrations of ECs from natural sources are not well-known and have been identified as an 

area where additional study is needed (Geschwind et al. 1999). 

Transport of ECs to Remote Areas 

In remote areas, determining the source of EC contamination is more difficult. ECs can be 

deposited directly in remote areas by humans or wildlife, or transported great distances 

atmospherically from sources far from the point of detection. Activities like swimming or 

angling, when users are likely to have personal care products (e.g., sunscreen, fragrances, DEET) 

on their skin, can introduce contaminants into the aquatic environment via direct human contact. 

The use of boats, all-terrain vehicles, and snowmobiles can result in the deposition of harmful 

byproducts from the combustion of fossil fuels (Ingersoll 1999). Backcountry campers and the 

5 
wastes they leave behind might also serve as a source. Human urine and defecation products are 

scattered about the landscape and, sometimes, inadequately treated in pit toilets. Outdoor 

recreators have also been known to use soaps and/or detergents in remote water bodies for 

bathing or cleaning dishes. These soaps may contain the antimicrobial agent triclosan, which is 

suspected of having effects on the thyroid system. Although the introduction of these compounds 

into remote streams or lakes may be infrequent, some of them may be very persistent in the 

environment, and if they are introduced during a vulnerable time period (e.g., developmental 

time period after eggs hatch), even very small concentrations could result in endocrine disrupting 

effects. 

For this type of nonpoint source, especially the impact of individual visitors in remote areas, 

there is a paucity of available research, but a few studies have evaluated the potential risk. In 

Kakadu National Park, Australia, there was a growing concern about the potential impact on park 

resources of EDCs introduced by swimmers at waterfall plunge pools and from a small 

wastewater treatment plant. Researchers conducted “tier 1” screening tests (Yeast Estrogen 

Screen, YES) to measure estrogenicity of park waters. Although they found some degree of 

estrogenic activity in their samples, they compared these values to current literature values and 

concluded that the levels observed during this preliminary research did not warrant immediate 

concern about the threat to aquatic life in the park (Hogan et al. 2005). This study suggests that 

ECs may not be of significant concern in all locations. The number of swimmers, the available 

dilution and the flow of the receiving waters are factors that influence the potential impact of 

swimmers on EC concentrations in remote areas. Results from this research indicate that 

screening tests like the YES can be a helpful tool in determining risk and the need for additional 

investigations, which could be useful in establishing an EC monitoring program to evaluate the 

potential risks within the National Park system. 

Sometimes ECs are found far from the sources, particularly in the case of pesticides that are 

transported atmospherically. There are several environmental and chemical factors that affect the 

distance a compound can travel and that determine where the compound is eventually deposited. 

Blais (2005) describes that the weight, volatility, vapor pressure, and condensation temperature 

of the contaminant all factor into whether or not it is likely to travel atmospherically. 

Environmental factors that affect the deposition of contaminants include air currents, quantity 

and type of precipitation, snowpack accumulation, altitude, and latitude. In their critical review 

of research from around the globe, Daly and Wania (2005) found that factors such as local and 

regional wind patterns, dominant form of precipitation, temperature inversions, proximity to 

sources (e.g., local use of pesticides), and weight and volatility of the compound of concern all 

affect the air transport and deposition patterns. They found that concentrations of some 

compounds decreased with elevation, others increased, and still others showed no clear 

correlation. 

Site specific examples of the principles discussed by Blais (2005), Daly and Wania (2005) 

include a study from the montane region of Costa Rica, where researchers found concentrations 

of several pesticides at high altitudes downwind of an active banana plantation. They modeled 

the fate of contaminants and found that the field results supported the model’s prediction that 

pesticides accumulate in the tropical mountains because of “enhanced precipitation scavenging at 

high elevations” (Daly et al. 2007). Similarly, the Canadian Northern Contaminants Program 

6 
(Blais 2005) and the National Park Service’s Western Airborne Contaminants Assessment 

Project (WACAP), discussed in detail below, further document the effect that cold temperatures, 

northern latitudes, high altitudes, and snowpack accumulation can have in determining the 

distribution of ECs (Hageman et al. 2006). The phenomenon where certain compounds have 

shown a tendency to accumulate in colder parts of the globe is referred to as “cold fractionation” 

(WACAP 2004). The research suggests that the potential for air transport and deposition will 

vary from site to site, but, considering the climatic patterns and surrounding land use, is 

important for determining the potential threat of ECs in montane parks. 

For other vectors of transport, such as wildlife, the ability of the compound to bioaccumulate is 

important in considering the global distribution of certain persistent toxics, such as dichlorodiphenyl-trichloroethane (DDT), polychlorinated biphenyls (PCBs), and chlordane. Migrating 

wildlife can carry significant concentration of ECs to remote areas of the globe. Blais (2005) 

cites several examples where migrating salmon and seabirds have served as vectors in 

transporting PCBs, DDT, other organochlorine compounds, and/or mercury to remote lakes in 

Alaska and Canada. 

Preventing EC Contamination 

With the increasing concerns about EC contamination has come an interest in finding ways to 

prevent contamination at the source. In February 2007, the Office of National Drug Control 

Policy issued new drug disposal guidelines to educate consumers on the proper method of 

disposing unwanted, unused, or expired prescription medications (ONDCP 2007). Communities, 

universities, and other organizations have sponsored one-day disposal events to collect unwanted 

prescription drugs, and some pharmacies have begun to place disposal bins in their stores to 

encourage proper disposal by customers. These efforts reduce the source of pharmaceuticals, 

thus preventing some quantifiable amount from entering the wastewater. 

At the other end of the pipe, researchers investigating the ability of a WWTF to remove ECs 

from wastewater have found that the removal effectiveness varies with the type of technology 

used in the treatment process. One USGS study found that effluent from trickling-filter WWTFs, 

one type of conventional treatment system, contained greater concentrations of OWCs than the 

effluent from other types of WWTFs in the study area (Lee et al. 2005). Research on engineered 

treatment wetlands also indicates that these systems provide little benefit in reducing 

concentrations of pharmaceuticals in effluent (Sedlak et al. 2004). Advanced treatment systems 

can significantly reduce the concentrations of ECs, but several factors can influence the 

effectiveness. Research by Snyder et al. (2006a) shows that membrane filtration is effective in 

removing many types of ECs; however, results depend on the type of membrane and the target 

compounds of concern. They also found that activated carbon systems can be up to 90% 

effective in removing ECs, but the presence of natural organic matter can negatively impact the 

results. Reverse osmosis and nanofiltration were highly successful in removing target 

compounds, but the compounds were then found at concentrated levels in the brine, thus raising 

the question of how to safely dispose of this waste stream. Ozone is also an extremely effective 

oxidant for decreasing the concentrations of ECs in treated wastewater. Certain compounds may 

require a higher dose to oxidize, which may be cost prohibitive for many treatment facilities. 

Hydrogen peroxide, although it can increase the rate of oxidation when added to the ozone 

7 
treatment process, did not show an overwhelmingly positive benefit to the process of removing 

ECs (Snyder et al. 2006b). 

Extent of ECs in National Parks 

To date, the majority of EC research has focused on downstream impacts of treated wastewater 

effluent, and as such, the studies are centered in more urban areas. Therefore, the majority of 

what is known about ECs in National Parks is confined to those that are influenced by WWTF 

effluent. However, there are also several studies documenting the ability of ECs to accumulate at 

high elevations due to atmospheric transport and deposition, including WACAP (mentioned 

above), which was initiated by NPS in 2002 to determine the extent of contamination in parks in 

the western U.S. The research on the variety of potential sources and contaminants suggests that 

the risk of contamination is likely to be park-specific based on the proximity to population 

centers and the surrounding land uses within both the watershed and airshed. The following 

sections contain summaries of existing research on ECs that were conducted in or near National 

Park Service units (Figure 1). 

Figure 1. Map of National Park Service regions and locations where research has been conducted 

in National Park Service units. 

8 
Pacific West Region 

Research conducted by the USGS and the U.S. Fish and Wildlife Service documented the 

presence of environmental contaminants, including EDCs and PPCPs, in parts of Lake Mead 

National Recreation Area (Bevans et al. 1996, Covay and Leiker 1998, Covay and Beck 2001, 

Boyd and Furlong 2002, Goodbred et al. 2007). These studies detected contaminants in water, 

sediments, and fish tissue, with the largest number of compounds and highest concentrations 

occurring in areas impacted by the discharge of municipal wastewater, groundwater, and 

stormwater, such as Las Vegas Bay. A study of Las Vegas Bay (Snyder et al. 1999) found five 

compounds with estrogenic activity, of which estradiol (a naturally occurring sex steroid 

hormone) and ethinyl estradiol (a synthetic estrogen used in birth control) had the highest 

estrogenicity. The studies not only found a variety of well known legacy chemical compounds 

that have not been used for decades, such as DDT and PCBs, but also a number of ECs, 

including commonly prescribed pharmaceuticals and consumer products like caffeine, 1,7-

dimethylxanthine (metabolite of caffeine), acetaminophen (pain reliever), carbamazepine 

(anticonvulsant), cotinine (metabolite of nicotine), sulfamethoxazole (antibiotic), and the 

microbial agent triclosan (Boyd and Furlong 2002; Rosen et al. 2006). Studies detected many 

ECs in Las Vegas Bay but not in other areas of the lake, indicating that the discharge of sewage 

effluent has a direct and localized impact on water quality in the lake (Rosen et al. 2006). 

Evidence collected from Lake Mead studies indicate that contaminants in effluents may 

adversely affect the health and reproduction of fish in receiving waters (Patino et al. 2003). 

These results are supported by the findings of similar studies throughout the world (Sumpter and 

Johnson 2005). Fish in receiving waters may be exposed to hundreds of chemical contaminants 

simultaneously, which makes it difficult to determine which individual compounds are altering 

endocrine and reproductive functions. Studies are ongoing in Lake Mead to determine which 

chemicals are the most active in causing endocrine and reproductive effects in fish, including 

common carp, largemouth bass, and the endangered razorback sucker. In addition, there is a 

collaborative research project underway to examine the efficacy of enhanced treatment for 

removal of emerging contaminants from effluents. 

In Golden Gate National Recreation Area, managers considered using treated wastewater as a 

source of irrigation water for Crissy Field. Concerns about the potential impact of ECs from the 

treated wastewater getting into and affecting the recently restored Crissy Marsh prompted a 

baseline study before irrigation began. USGS researchers used passive samplers at several 

locations within the marsh and one in San Francisco Bay to determine if there were EDCs 

present, and used the YES assay to establish if any estrogenic compounds were present. The 

results of the research (Alvarez and Perkins 2006) confirmed the presence of compounds 

“capable of producing an estrogenic response” before the irrigation had started, but not enough 

information was available to ascertain the ecological effect of these compounds. 

A review by Daly and Wania (2005) noted that the insecticides chlorpyrifos, diazinon, and 

parathion were detected in Sequoia National Park. Unlike the studies identified above, this 

review focused on the mechanisms for atmospheric transport and deposition from areas of heavy 

pesticide use in California’s Central Valley to remote montane parks in the Sierra Nevada, such 

as Sequoia National Park. Although many of the compounds reviewed by Daly and Wania 

9 
(2005) are currently regulated, their transport and fate into remote montane areas could be 

indicative of the potential for atmospheric transport of the newer ECs. 

Intermountain Region 

One study conducted in Yellowstone National Park evaluated snowmobiles as a source of 

contamination of the winter snowpack. The researchers found elevated levels of fossil fuel 

combustion byproducts (e.g., toluene, xylenes, benzene) near snowmobile routes, but in their 

preliminary analysis, they stated that the concentrations were not suspected to be problematic as 

they were below the detection limit of 10 ng/L (Ingersoll 1999). However, there is more recent 

evidence to suggest that toluene may be an endocrine disruptor (Yamaguchi et al. 2002). As 

such, additional evaluation may be warranted to determine whether the concentrations are 

environmentally relevant. 

In Rocky Mountain National Park, Usenko et al. (2007) sampled sediment cores and winter 

snowpack from two lakes, which are approximately 10 km apart, but on opposite sides of the 

Continental Divide. They analyzed samples for semivolatile organic compounds (SOC) that were 

historically or are currently in use. While the deposition of historic-use SOCs, such as nonachlor, 

dieldrin, DDT, and PCBs, decreased after federal regulations prohibited their use, it has not been 

completely eliminated, which may be due to local revolatization. As expected, the deposition of 

current-use SOCs increased as their use increased, including endosulfan, dacthal, polyaromatic 

hydrocarbons (PAHs), and polybrominated diphenyl ethers (PBDEs). There were also significant 

differences in the concentrations of the target compounds between the two lakes, which the 

researchers suggest could be attributed to regional summer wind patterns. Their findings suggest 

that topographic barriers can play a significant role in determining the atmospheric transport and 

deposition of SOCs to high elevations. 

Southeast Region 

In the Chattahoochee River National Recreation Area, researchers found low concentrations (<1 

ug/L) of individual OWCs, but higher concentrations of mixtures (>1 ug/L). Of the contaminants 

detected, thirteen are suspected endocrine disruptors (Frick and Zaugg 2003). So, while the 

individual OWCs might not have been detected at environmentally relevant levels, it is possible 

that the concentration of the mixtures is relevant. The effects of these mixtures on human health 

and aquatic life are unknown. 

The Comprehensive Everglades Restoration Program identified treated wastewater as a possible 

source of water for restoring the natural hydroperiods to the coastal wetlands of Biscayne Bay. 

Prior to using the treated effluent, the USGS conducted sampling on the effluent to determine the 

presence of ECs. While they found that the treatment process was effective in reducing the 

concentrations for many ECs, they still found detectable levels. The compounds included 11 

pharmaceuticals, eight antibiotics, and one hormone with “‘known’ endocrine disrupting 

potential” (Lietz and Meyer 2006). 

10 
Midwest Region 

Two studies on major riverways in the Midwest document the impact of effluent from WWTFs. 

One report cites research indicating that estrogenic compounds from WWTFs are impacting fish 

in the Mississippi National River and Recreation Area (Lafrancois et al. 2007). Scientists found 

concentrations of nonionic surfactants in over 74 miles of the Cuyahoga River, which flows 

through Cuyahoga Valley National Park (Rice et al. 2003). Research by Oliaei (2005) 

documented perfluorinated compounds, which are manufactured by 3M, in 50% of fish sampled 

in Voyageurs National Park. 

Northeast Region 

In Cape Cod, researchers found that residential septic systems were contaminating groundwater 

with estrogenic compounds (Swartz et al. 2006). This study suggests that septic systems are not 

completely effective at removing compounds that may act as endocrine disruptors and that these 

compounds have the potential to move through the groundwater system. Although the exact 

location of the study is not known, it is likely in the vicinity of Cape Cod National Seashore. The 

impact of septic systems as a source of wastewater contamination at the Seashore is unknown. 

Alaska Region 

Some ECs have the potential to bioaccumulate. In an EC source study, Ewald et al. (1998) found 

that the population of migrating salmon served as a significant transport vector for PCBs and 

DDT to freshwater inland lakes. As the salmon migrated upstream, their lipids were used as an 

energy source, which resulted in the redistribution of the pollutants to other tissues of the 

organisms. For example, in females the pollutants accumulated in the gonads, which may have 

affected the survival of eggs and fry. After spawning, the Pacific salmon died, leaving their body 

burden of PCBs and DDT in the environment, contributing to the bioaccumulation in the local 

freshwater food web. The study took place along the Copper River upstream of Wrangell-St. 

Elias National Park and Preserve. While PCBs and DDT are no longer used in the U.S., they are 

used in other parts of the world and are very persistent in the environment, and as such, salmon 

maturing in various areas of the Pacific Ocean could be exposed. Current research suggests that 

biotransport could be a significant factor in the movement of bioaccumulative compounds that 

would not otherwise be found as a result of air deposition or the presence of local source. 

Regional and National Studies 

The NPS initiated WACAP to evaluate the risk of contamination from long-range transport of 

compounds to western National Parks. The project analyzed the deposition of semi-volatile 

organic compounds, which include persistent organic pollutants such as PCBs and DDT, and 

current-use and historic-use pesticides in the western U.S. WACAP results confirm other 

research of long-range transport in northern latitude and Arctic environments, such as those 

documented by the Canadian Northern Contaminants Program (Macdonal et al. 2000). In a study 

of pesticide deposition in several National Parks located in California, Colorado, Washington, 

and Alaska, Hageman et al. (2006) found that transport and deposition of pesticides was largely 

attributed to regional use, as supported by a significant correlation between the cropland intensity 

11 
and snowpack concentrations of agricultural pesticides. However, in places where they found 

detections and no significant regional sources, such as Alaska, transport and deposition was, 

therefore, attributed to long-range transport across the Pacific Ocean (Hageman et al. 2006). 

Current use pesticides that are suspected endocrine disruptors, dacthal, chlorpyrifos, and 

endosulfan, were frequently detected. This research suggests that while parks near agricultural 

land are probably at a greater risk of exposure to contamination by regional use of pesticides, 

more remote parks may still be at risk as well. 

As noted above, research by Kolpin et al. (2002) has documented the presence of OWCs in 

waters receiving effluent from WWTFs throughout the U.S. The streams were selected in areas 

that were likely to be at risk of contamination by municipal, industrial, or agricultural 

wastewater. As such, this study does not represent the probability of OWC being present in all 

streams throughout the U.S. Nevertheless, it shows that if sources of wastewater are present near 

a National Park it is probable that ECs will be in the streams receiving the discharge. Several of 

the study sites were in or near National Park Service lands (Figure 2). 

US States

Major Lakes

NPS Unit Boundaries

0 500 1,000

®

Miles

Point Reyes

N.S.

Lake

Roosevelt

N.R.A.

Saguaro N.P.

Tumacacori

N.H.P.

Mississippi

N.R.R.A.

Cuyahoga

Valley

N.P.

Chattahoochee

River N.R.A.

Boston Area

NP Units Lowell

N.H.P.

Bighorn

Canyon

N.R.A.

Little Bighorn

Battlefield N.M.

Figure 2. Parks labeled are in the vicinity of a USGS monitoring site included in Kolpin et al. 

(2002) study on organic wastewater contaminants. Captain John Smith Chesapeake National 

Historic Trail not shown. 

In a study by Rattner et al. (2005), many National Parks were identified has having little or no 

ecotoxicological data. The focus of the research was to determine data gaps to help guide future 

12 
monitoring efforts, and although they did not focus specifically on ECs, the parks identified by 

the researchers as vulnerable to pollution might also be at greater risk of being impacted by ECs. 

What they found is that there was no recent data for approximately half of the National Parks in 

the geographic area of the toxicology database, which targeted coastal habitats. There were 59 

parks in watersheds “exhibiting serious water quality problems and/or high vulnerability to 

pollution” that did not have recent data. Overall, there was very little herpetological data 

available, especially for the Pacific Coast and Hawaii. The figures below highlight the largest 

park units identified in the report as lacking ecotoxicological data (Figure 3) and as being located 

in problematic watersheds that may make the parks vulnerable to pollution (Figure 4). 

Figure 3. Map of largest National Park units identified by Rattner et al. (2005) as lacking 

ecotoxicological data. 

13 
Figure 4. Map of largest National Park units identified by Rattner et al. (2005) as being located 

in watersheds with “more serious water quality problems,” with a “high vulnerability to 

pollution,” and lacking data. 

14 
Future Research Needs 

 

While the existing research on the occurrence and distribution of ECs across the U.S. and the 

effects on certain aquatic populations has begun to elucidate the possible impacts of ECs in the 

environment, the literature identifies multiple areas of research to further the mechanisms and 

understanding of this complex issue. 

There is limited research on the presence, transport, fate and extent of ECs in National Parks. 

While this report identifies parks where studies have shown the presence of ECs and discusses 

some activities (e.g., swimming and horseback riding) that are potential sources of EC 

contamination, there are other sources of ECs and environmental factors influencing the risk of 

contamination that have not been comprehensively studied or analyzed in the literature. One 

approach for prioritizing further research in National Parks would be to develop a risk 

assessment procedure using existing information. After developing a priority ranking of parks 

based on vulnerability to EC contamination, field studies using passive samplers and methods to 

detect estrogenic compounds (e.g., in vitro assays and YES) can direct further analytical tests to 

identify the specific compounds of concern. This approach, known as the contaminant 

assessment process (CAP), has been used by the USGS to assess the threat of environmental 

contamination on other lands managed by the Department of the Interior and could be similarly 

useful for better understanding the extent of environmental contaminants in the National Park 

system. The results of such an approach could then be used to inform the development of 

management plans to minimize any potential negative impacts of contamination. 

Further information is needed about the degradation and distribution of ECs in the environment. 

Laboratory results from Borch et al. (2007) indicate that photolysis might be an important 

degradation mechanism, but in general, the degradation rates of hormones in the aquatic 

environment, as introduced by livestock or wildlife, are not well known. As Kolpin (2007) 

discussed, the compounds detected in high concentrations in water were detected in low 

concentrations in sediments and vice versa. As such, concentrations in sediments and water need 

to be evaluated because each compound is transported in different ratios across various media 

depending on its physical and chemical properties. 

There is a lack of baseline data on EDCs in the environment (Geschwind et al. 1999). Methods 

for determining intersex still need to be developed and standardized among investigators. 

Presently, it is unclear how many oocytes in a testis have (or what percentage of feminized tissue 

has) a substantial effect on sperm production or general reproduction of a population of fish. 

Also, scientists do not know what percentage of male fish of various species might naturally 

exhibit intersex characteristics, identifying a further need for baseline data. There needs to be a 

better method for distinguishing between the effects resulting from exposure to natural (e.g., 

plant derived phytoestrogens) and anthropogenic sources of estrogen. 

Researchers are calling for an increased focus to look holistically at the impacts of mixtures of 

ECs in the environment (Geschwind et al. 1999). In some cases, the metabolites and degradates 

of ECs are found in higher concentrations in the environment than their parent compounds 

(David et al. 2003; Osano et al. 2003; Hackett et al. 2005) and may have a more significant 

15 
environmental impact. Future research needs to consider the presence, fate, transport, and 

impacts on aquatic life of these metabolites. 

16 
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