MMSD Watercourse Corridor Study: Contaminants in Water and Sediment

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There are many kinds of chemical, physical, and biological contaminants contained in water and sediment, and new or “emerging” contaminants are continually being discovered. USGS investigations of contaminants in the MMSD Watercourse Corridor Study include studies of PAHs, microplastics, wastewater contamination, waterborne pathogens, as well as modeling long term trends in water quality.

During the current 5-year study period for Phase V (2016-2020) of the Milwaukee Metropolitan Sewerage District (MMSD) Watercourse Corridor Study, the following four topics are being addressed by one or more USGS subprojects:

1.    Ecological Assessments and Trends
2.    Geomorphology and Sediment Studies Related to Stream and Estuary Rehabilitation
3.    Contaminants in Water and Sediment
       a.    Evaluation and Trends of PAH Source Contributions in Lake and Stream Sediments
       b.    Microplastics in Milwaukee-Area Streams
       c.    Hydrologic and Temporal Dynamics of Wastewater Contamination Using Dissolved Organic Matter
       d.    Hydrologic and Seasonal Variation in Waterborne Pathogen Loadings
       e.    Water-Quality Trends in Milwaukee-Area Streams and Jones Island Streamflow
4.    Continuous Real-Time Streamflow

This webpage focuses on topic 3. Contaminants in Water and Sediment.

 

There are many kinds of potential contaminants contained in water and sediment in our rivers and lakes, and new or “emerging” contaminants are continually being discovered because of improvements in analytical techniques as well as the addition of new types of contaminants. Contaminants can be chemical, physical, or biological. For example, chemical contaminants can include metals and metal-like chemicals (e.g., copper, lead, zinc, and mercury to name just a few), organic/carbon-based chemicals (e.g., DDT, PCBs, PAHs), or nutrients (for example, nitrogen, phosphorus, and sulfur). Physical contaminants can include such things as fine sediment or trash that can also carry attached chemical and biological contaminants. Biological contaminants can include bacteria, viruses, and those that are pathogenic or indicators of potential pathogen presence that may also pose a hazard to humans or animals. Depending on their nature and chemical makeup, contaminants may be associated more with water or with sediment, and the association can change with time because of physical, chemical, or biological interactions with a contaminant. There are a wide variety of natural and anthropogeniccontaminant sources with various mechanisms for fate and transport that may be influenced by human activities.

USGS investigations of contaminants in Phase V include studies of PAHs, microplastics, wastewater contamination, waterborne pathogens, as well as modeling long term trends in water quality.

3a. Evaluation and Trends of PAH Source Contributions in Lake and Stream Sediments

BACKGROUND

Previous USGS/MMSD studies have shown that PAHs likely pose a greater risk to Milwaukee-area stream ecosystems than any other class of contaminants, with concentrations in streambed sediment above aquatic toxicity thresholds at most locations (Baldwin and others, 2013). Natural and manmade sources contribute to PAH presence in the environment, including emissions from volcanoes, forest and grassland fires, vehicles and power plants, tire particles, motor oil, crude oil, and coal-tar-based pavement sealcoat (CTS). Comparison of Milwaukee-area streambed sediment samples collected in 2014 with the chemical signatures of various PAHs indicated that CTS is likely the dominant source of the PAHs to Milwaukee area streams (Baldwin and others, 2017). Previously, studies in other areas have also identified CTS as the primary source of PAHs in sediments (Van Metre and others, 2009, 2010; Mahler and others, 2012; Pavlowsky, 2013; Crane, 2014). Considering this body of evidence, many cities, counties, and states, including Dane County, WI (2007), Milwaukee (2017) and more than fifteen communities near Milwaukee (2017-2019), have enacted a ban on the use of high-PAH pavement sealants.

OBJECTIVES

This project aims to evaluate differences in stream and lake sediment PAH content in areas of southern Wisconsin with and without high PAH (> 1 percent PAHs) pavement sealant bans. Specific objectives are as follows:

  1. Compare PAH content and PAH profiles in stream sediment quality in areas with and without active high PAH pavement sealant use.
  2. Compare PAH content and PAH profiles in lakebed sediment quality over time using sediment dating techniques in areas with and without active high PAH pavement sealant use.
  3. Establish a long-term (>10 years) stream sediment monitoring program for tracking PAH concentrations by examining trends in PAH signatures over time from before the high PAH pavement sealant ban and at least 10 years after implementation bans in the Milwaukee area.

APPROACH

This study has three components to achieve objectives:

Component 1 includes examination of PAH signatures in urban streams of Milwaukee, where bans did not exist before 2017, with Dane County, WI, where a ban of high PAH pavement sealant was implemented in 2007. A total of 21 sites were chosen to represent different levels of urban influence in both regions, including 14 streams in the Milwaukee area. Milwaukee area streams were sampled in June 2018

Component 2 will include two urban lakes in the Milwaukee area (Little Muskego and Northridge Lakes) and two urban lakes in the Madison area (Lakes Mendota and Monona). In winter 2018, cores were collected, split into samples representing multiple depths and years. Samples are being analyzed for PAHs, carbon, and age dating. Results will be analyzed to examine temporal trends in PAH content and the composition of the PAH profile to determine if sources have changed over time. Comparisons will be made between the two regions to determine if the ban of high PAH pavement sealants have influenced the results.

Component 3 will include analysis of trends in the PAH signatures from streams with urban influence that were chosen for Component 1. Streams will be sampled once each year at each Component 1 site for the remainder of Phase V (through 2020). The relative magnitude of PAH presence as well as the composition of the PAH profile will be examined to assess temporal trends.

CONTACT

 

3b. Microplastics in Milwaukee-Area Streams

BACKGROUND

Microplastics, plastic particles less than 5mm in diameter, have been a known contaminant in marine waters (Thompson and others, 2004; Moore, 2008), and research has begun to define characteristics of microplastics in freshwater systems (Lechner and others, 2014). Several studies have reported microplastic concentrations in rivers and lakes to be as high, or higher, than those in marine environments (Yonkos and others, 2014). Results from a study of Great Lakes tributaries found median concentrations nearly an order of magnitude higher in tributaries than in the Great Lakes (Baldwin and others, 2016).

Potential pathways which introduce various microplastic sources to freshwater systems include, but are not limited to, the breakdown of larger plastic litter in urban runoff (e.g., Styrofoam, plastic bags, bottles, wrappers, cigarette butts) and wastewater treatment plant effluent (e.g., synthetic fibers from clothing and textiles, fragments of larger debris, microbeads from personal care products).

Previous research on microplastics focused on the surface of a water-body to quantify occurrence and abundance. Little research has been done to characterize microplastic prevalence at different depths within the water column. In 2016, the U.S. Geological Survey, Milwaukee Metropolitan Sewerage District, and State University of New York at Fredonia collaborated to characterize the vertical distribution of microplastics in the water column, surface water, and surficial sediments at locations throughout the Milwaukee area ranging from rivers to nearshore Lake Michigan.

OBJECTIVES

The objective of this research is to determine how the abundance and type of microplastics particles changes with depth in the water column, and to define the quantity of particles that are contained in bed sediment of streams, estuaries, and nearshore Lake Michigan.

APPROACH

Sampling locations will be established on the Kinnickinnic, Menomonee, and Milwaukee Rivers, in addition to inner- and outer-Milwaukee River harbor and Lake Michigan. Ten locations in total will be sampled for microplastics at the water surface, and various depths within the water column, and in the surficial sediment. At the three most upstream river locations, mid-column water samples will not be collected because of depth restrictions. Water samples will be collected four times at each location, from late spring into early fall. Results will be analyzed and presented to better understand the movement of the different types of microplastics (fibers, fragments, foam, etc.). In addition, data will be analyzed to learn about how the distribution of microplastics in the water column changes in different hydraulic settings (e.g. shallow, turbulent, and deeper, quiescent waters).

CONTACT

 

3c. Hydrologic and Temporal Dynamics of Wastewater Contamination Using Dissolved Organic Matter

BACKGROUND

One well established approach for investigating the composition of dissolved organic matter (DOM) in aquatic systems includes the measurement of optical properties. A fraction of the chemicals included in natural organic matter and anthropogenic substances interact with light, which allows them to be measured by absorbance and fluorescence methods (optical properties). The extent to which light of a certain wavelength interacts with the organic matter reflects the chemical composition of the organic matter, permitting the identification of contaminant sources in environmental waters using optical fluorescence methods. Optical measurements are rapid, inexpensive, reliable, and can be made in the laboratory or field.

Laboratory studies have used fluorescence measurements as indicators of human- and animal-derived wastewater (Bergamaschi et al., 2005). Previous studies have found an association between fluorescence values and the magnitude of wastewater contamination in small creeks and coastal systems (Hartel et al., 2008; McDonald et al., 2006, Hudson et al., 2007).  Preliminary work from previous sampling efforts in the Milwaukee area indicated similar approaches may be useful in relating the optical properties of water to wastewater contamination in area surface water. Once relationships to specific types of contamination have been established, optical measurements can allow for real time estimation of sewage indicators for better definition of the dynamics of sewage contamination in surface water environments.

OBJECTIVES

The objective is to use currently available optical sensor technology to characterize the dynamics of wastewater contamination in Milwaukee area streams. Specific objectives are as follows:

  1. Use results from the Watercourse Corridor Study Phase IV sampling to develop preliminary relations for measuring the likelihood and magnitude of wastewater contamination in surface water in a real-time setting.
  2. Characterize surface water DOM and wastewater-derived DOM by discrete sampling over the course of event hydrographs, and during low-flow conditions to understand patterns in hydrologic and temporal variability.
  3. Design and implement customized in situ fluorescence and absorbance instrumentation for continuous real-time DOM and wastewater-derived DOM characterization in a local stream.

A separate project with the Great Lakes Protection Fund (MMSD is a partner) will focus on using optical properties of water to track sewage sources back to the source of contamination. This project will be focused on the development of optical sensors to be used for continuous deployment in streams.  Such sensors will allow for a real-time assessment of wastewater presence in Milwaukee surface waters and will enable detection of wastewater signals across varying hydrologic and seasonal conditions.

APPROACH

The practicality of using in situ optical measurements as tools for continuous real-time assessment of human wastewater contamination in the Menomonee River watershed will be evaluated.  Initial relations between optical properties and human-associated bacteria (a measure of sewage contamination) will be developed with data collected during Phase IV to provide a preliminary assessment of the optical signals that will be predictive of wastewater contamination. Sensors will be deployed with these signals to provide a continuous estimate of wastewater contamination. Additional water samples will be collected and analyzed for optical properties of water (fluorescence, absorbance, and dissolved organic carbon) and human-associated bacteria for a range of flow conditions throughout different seasons in the lower Menomonee River watershed. Results will be used to validate relations from previous data and further optimize the wastewater sensors. These samples will be collected in two different ways:

  1. Composite samples will be collected through extended durations concurrently with samples from another Phase V project and analyzed for waterborne pathogens, indicator bacteria, and pharmaceutical compounds;
  2. Discrete samples will be collected during selected runoff hydrographs and baseflow periods to characterize the short-term dynamics of wastewater contamination in the Menomonee River.

In addition, several source samples with likely contributions of DOM will be collected to identify potential interferences with wastewater signals, and to identify wastewater signals that could be used to avoid these interferences.

Data collected will be used to develop and optimize specifications for optical field sensors.  The goal for this project is to use the sensors at a fixed station to capture the timing and magnitude of wastewater pulses in the stream.

CONTACTS

For excitation and emission data in gallery above: These data are preliminary or provisional and are subject to revision. They are being provided to meet the need for timely best science.

3d. Hydrologic and Seasonal Variation in Waterbourne Pathogen Loadings

BACKGROUND

Wastewater contamination from imperfect or damaged infrastructure can introduce many types of contaminants to receiving waters, including waterborne pathogens (viruses and bacteria), toxic and endocrine disrupting chemicals, and nutrients such as phosphorus and nitrate. Pathogens, including human-specific viruses (HSV), bovine-specific viruses, and zoonotic bacteria have been detected in streams with mixed, rural, and urban watershed land use, indicating a potential hazard to humans and animals. While pathogens are an important measure of water quality and can serve as indicators of wastewater presence, dynamics within host organisms can mean that pathogens are often not detected even when wastewater contamination is present. Human-associated indicator bacteria (HIB) analysis in water samples has also proven to be a valuable source of information for assessing wastewater contamination (Templar and others, 2016). The perpetual presence of HIB in wastewater at high concentrations (approximately 107 counts/100 ml) allows for detection of wastewater contamination even at high dilution levels. Pharmaceutical compounds can serve as a chemical measure of water quality that serves as additional evidence of wastewater contamination with human waste as the primary source. 

Waterborne pathogens have been studied for multiple years within the Milwaukee and Menomonee River Basins during Phase III and Phase IV of the Watercourse Corridor Study, indicating substantial long- and short-term variability in pathogen presence and magnitude (Corsi and others, 2003, 2014; Lenaker and others, 2018). Results from these previous studies have begun to provide fundamental information needed to assess the prevalence of pathogens in Milwaukee-area watersheds and the environmental conditions in which they persist. Additional information contributing to a long-term record and providing pathogen data at a finer time-scale are necessary to provide further insight into the important factors driving pathogen presence and magnitude in these streams. Since pathogens are not always present in the population, even when wastewater contamination is present, pathogens may not be detected. Concurrent collection of samples for additional indicators of wastewater contamination (e.g. pharmaceutical compound data and HIB) can provide multiple lines-of-evidence and reduce uncertainty in the assessment of wastewater contamination presence.

OBJECTIVES

The overall objective of this study is to better understand sources of wastewater contamination and associated waterborne pathogens to rivers in the Milwaukee area. A primary focus of this study is to determine the relative magnitude of contributions from areas served by municipal wastewater systems on a bi-weekly basis at two stream locations to understand variability in wastewater contamination as defined by HSV occurrence, HIB, and pharmaceuticals present in the urban aquatic environment. Specific objectives are to 1) quantify waterborne pathogen, HIB, and pharmaceutical concentrations and loadings on a bi-weekly basis at two locations over a 2-year period (2017-2019); 2) define human wastewater contributions (concentrations and loadings) to surface water by use of HSV, other pathogens, HIB, and pharmaceutical compounds; 3) examine relations between pharmaceutical compounds, pathogen occurrence, and wastewater presence; and 4) examine relations between climatic variables and water-quality parameters with wastewater loadings.

APPROACH

The study approach contains two primary components to define contributions of wastewater and related pathogen presence in Milwaukee area watersheds: (1) pathogen content will be measured and (2) chemical and microbial tracers of wastewater will be measured in water samples. Pathogen and water samples will consist of fixed interval bi-weekly 5-day composite samples collected at two selected streams. Pathogen (human-specific viruses, zoonotic bacteria, and bovine viruses), microbial (HIB), and pharmaceutical loadings will be computed for the stream monitoring sites on a bi-weekly and annual basis. Short term variability from individual samples will also be assessed. Two stream sampling locations within the Milwaukee area will be monitored for this study. One sampling location will represent a small urban watershed (Underwood Creek) served primarily by municipal wastewater systems, and a second location (Menomonee at 16th St.) will represent a mixed watershed that is served by municipal wastewater systems but also includes septic systems further upstream in the watershed that have potential to contribute wastewater contamination. Sampling will be conducted using an auto-sampling filtration system specially designed by USGS and the USDA for filtration of pathogens and collection of composite whole water samples. This sampler allows for unattended sampling, throughout stormflow and low-flow periods, resulting in flow-weighted composite samples. Streamflow data will be collected at each sampling location.

A comparative evaluation of the three different wastewater indicators will be conducted, and an overall assessment will be made based on collective information from these sources of information. This will include total wastewater contributions, seasonality, and influence of variable hydrologic conditions.

CONTACTS

  • Pete Lenaker (USGS Upper Midwest Water Science Center)
  • Steve Corsi (USGS Upper Midwest Water Science Center)
  • Joel Stokdyk (USDA-ARS and USGS Laboratory for Infectious Disease and the Environment)
  • Mark Borchardt (USDA-ARS and USGS Laboratory for Infectious Disease and the Environment)

 

3e. Water-Quality Trends in Milwaukee-Area Streams and Jones Island Streamflow

BACKGROUND

The past 40 years have seen a multitude of changes in the Milwaukee area.  In addition to substantial landscape and stream alterations occurring during this time, operation of the Deep Tunnel commenced in 1993. These changes have the potential to influence water quality in Milwaukee area watersheds. MMSD, USGS, and other agencies have collected water quality and streamflow information for many water quality parameters in multiple streams over this period. USGS has recently developed advanced statistical techniques to detect temporal trends in long-term water-quality datasets such as these, while accounting for variable flow and seasonality (Hirsch, Moyer, and Archfield, 2010, Hirsch and De Cicco, 2014). These statistical techniques as well as numerous graphical visualization options are included in the Exploration and Graphics for RivEr Trends software package (EGRET; https://github.com/USGS-R/EGRET/wiki). EGRET was used to assess trends in chloride concentrations during Phase IV of the Corridor Study and will be extended in Phase V to analyze long-term trends in additional high-value parameters including fecal coliform, total phosphorus, ammonia, biochemical oxygen demand, and total suspended solids. Application of these techniques to additional water-quality parameters in the Milwaukee area will provide valuable insight into patterns of water-quality change, possible causes of changes, and will help inform additional decisions related to watershed management actions in the coming years.

Results from the Phase IV investigation regarding chloride concentrations yielded valuable insights into long-term trends while also contributing to the knowledge base surrounding the modeling technique.  With relation to chloride, this study found that concentrations in the Milwaukee area have been increasing at a rate faster than urbanization, and that increasing concentrations are present during all seasons, trends similar to other northern urban areas in the US (Corsi and others, 2015).  With relation to the knowledge base surrounding this modeling technique, the Phase IV investigation yielded new graphical displays that have been incorporated into the EGRET software package and provided preliminary methods for the calculation of exceedance probabilities, which will be expanded upon and then incorporated into the EGRET software package in future releases.

OBJECTIVES

The overall objective of this study is to examine historical data for streams in the Milwaukee area to identify patterns of change in water quality and provide this information to stakeholders such as MMSD, other watershed managers, and policy makers to help inform future watershed management decisions.  Specific objectives are as follows:

  1. Identify high value water-quality parameters with sufficient data, spatial distribution, and temporal distribution for trend analysis
  2. Define trends for high value parameters meeting the model data requirements
  3. Present resulting information to stakeholders and publish results

APPROACH

Existing water-quality data in the Milwaukee area will be mined and assessments will be completed to determine whether there are sufficient data for evaluation of temporal trends.  Several parameters of high value to MMSD and their future planning efforts have been identified and are believed to be good candidates for use with this modeling technique. These parameters include fecal coliform, total phosphorus, ammonia, biochemical oxygen demand, and total suspended solids. Eighteen sites around the Milwaukee area have been selected, and data will be analyzed with the Weighted Regressions on Time Discharge and Season (WRTDS) model contained within the EGRET software package to examine changes in water quality over extended periods of time.

CONTACTS