Mercury Biomonitoring in Minnesota

MERCURY BIOMONITORING IN MINNESOTA

A Senior Project submitted to the Faculty of the Biology, Society, and Environment Program, University of Minnesota, in partial fulfillment of the

requirements for the Bachelor of Arts

Allison E. Fast

10 May, 2013

Abstract

There is considerable biomonitoring data nationwide on human exposure to various chemicals.

Despite this, there are often disparities in biomonitoring data that limit the full knowledge of

exposure. In the state of Minnesota, these disparities include a lack of data on mercury exposure

in vulnerable populations and at a baseline level in the general state population. The results of a

pilot Minnesota Department of Health mercury biomonitoring study revealed ten percent of

newborns in a Lake Superior Basin population had blood mercury concentration levels that

exceeded the United States Environmental Protection Agency’s Reference Dose for methyl

mercury of 5.8 µg/l. These results sparked additional interest in mercury biomonitoring on a

statewide level, the characterization of human mercury exposure, as well as the validation of the

novel laboratory procedure used to measure total mercury in the Minnesota Department of

Health pilot mercury study. With goals of exploring the characteristics of mercury exposure in

the state of Minnesota, the Minnesota Department of Health embarked on a series of mercury

biomonitoring studies. These studies, along with increasing the biomonitoring capacity of the

state, have allowed for the continued exploration of statewide mercury exposure, novel ways of

analyzing exposure levels in the laboratory, and intervention efforts to increase public awareness

and education of the dangers of mercury exposure.

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Acknowledgements

I thank my project adviser, Dr. Ruby Nguyen, for her continued structure, guidance, and support

throughout the entirety of this project. In addition, I thank Patricia McCann and Dr. Jessica

Nelson for their clarification of MN LSB and EHTB, and my Biology, Society, and Environment

adviser, Dr. Jeanette Simmonds, for her advice and aid in the planning of this project.

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Abstract ………………………………………………..………………………………………… 1

Acknowledgements …………………………………………………..………………………….. 2

Mercury Biomonitoring in Minnesota ……………………………….………………………….. 4

References... ……………………………………………………………………………………. 22

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Human exposure to mercury is a significant public health issue that affects individuals

nationwide. The public health concern over the sources, distribution, and severity of mercury

exposure in Minnesota is addressed through the efforts of the Minnesota Department of Health

(MDH). Through the biological monitoring, or biomonitoring, of chemicals and their

metabolites in human hair, blood, or urine, the measurement of human exposure to harmful

substances is a useful tool in determining characteristics of human exposure to chemicals (Minn.

Stat. §144.995 2008). Initiated in 2007 along with the Environmental Health Tracking Program,

the Biomonitoring Program at MDH is instrumental in developing a baseline of mercury

exposure, as well as exploring the characteristics of exposure in vulnerable populations in

Minnesota. In addition to its work in characterizing the determinants and distribution of mercury

exposure in the state, the MDH Environmental Health Tracking and Biomonitoring Program

(EHTB) pioneered a novel laboratory method for the measurement of total mercury

concentration in dried blood spots (DBS). Created with the intention of increasing the

biomonitoring capacity of state, EHTB helped increase the knowledge of the distribution and

characteristics of mercury exposure in Minnesota (Environmental Health Tracking and

Biomonitoring 2013). The results of a pilot MDH study, that showed elevated blood mercury

concentrations in a population of Minnesota newborns, initiated a subsequent series of mercury

exposure studies. In addition, the results of the pilot MDH study led to the creation of multiple

long term goals of increasing the understanding of mercury exposure throughout the state to

better educate and protect populations from dangerous exposure. Through the investigation of

the characteristics and measurement of mercury exposure, mercury biomonitoring in Minnesota

was successful in establishing a baseline of exposure, increasing the biomonitoring capacity of

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MDH, and increasing awareness and education of the dangers of mercury exposure in the state of

Minnesota.

Mercury is a metallic chemical element that is naturally occurring in the environment. In

its metallic state, mercury is a shiny, silver-white, odorless liquid that when heated, becomes a

colorless and odorless gas (ChemicalBook 2008). Mercury exists in three separate oxidation

states including mercuric (Hg2+¿ ¿), mercurous (Hg22+¿ ¿), and metallic (Hg0). Forming various

inorganic and organic compounds, mercury undergoes a consistent transformation and speciation

change that influences its environmental effects and toxicity. Mercury undergoes a global cycle

in which it transforms its chemical forms, as well as cycles through the environment, in a process

known as the “ping-pong” effect (World Health Organization 1990, 29-30). Constantly cycling

between water, land, and the atmosphere, mercury undergoes a biological transformation from an

inorganic to an organic state in aquatic systems. Once in water, inorganic mercury may begin the

conversion to an organic mercury compound, such as methyl mercury, through the process of

methylation. The conversion is enabled by the non-enzymatic methylation of inorganic mercury

by the compound methyl cobalamine. Once converted to methyl mercury, or another organic

compound, mercury enters the food chain by rapidly diffusing throughout the aquatic system and

tightly binding to proteins in wildlife. Unlike other forms of mercury, organic mercury is able to

accumulate in humans and animals. Because of this, methyl mercury is rapidly accumulated by

most aquatic organisms and is able to attain high concentrations in fish at the top of the food

chain through the process of biomagnification (World Health Organization 1990, 29-31). The

mercury that has accumulated in fish and other aquatic species enters the human body when the

fish are consumed. Upon being absorbed by the gastrointestinal tract, mercury from the tissue of

the fish is transferred to the blood and tissue of the human, where it accumulates and is

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eventually excreted. The methylation of inorganic mercury and its subsequent accumulation in

the aquatic food chain through biomagnification assures ingestion as the most common form of

methyl mercury exposure (Eccles and Annau 1987).

The bioaccumulation of methyl mercury in many aquatic species, such as fish, is enabled

through the emission of mercury into the surrounding environment through a variety of natural

and manmade sources. Emissions from volcanoes, bodies of water, and the degassing of the

earth’s crust, all release metallic mercury into the atmosphere where it is then washed down to

land and bodies of water through precipitation or dry atmospheric deposition (World Health

Organization 1990, 24-31). Various anthropogenic activities, such as mining, have increased the

release of metallic mercury from the earth into the atmosphere, as well as emitting additional

mercury into the atmosphere through the process of smelting. In addition to the leaching of

mercury into the environment from mining and natural degassing, a variety of industrial

processes utilize various forms of mercury or mercury-containing compounds in products and

manufacturing. Pollution and runoff from mining and industrial processes contribute to the

burden of mercury in bodies of water and the atmosphere through the direct discharge of waste

(U.S. Geological Survey 2010). The presence and accumulation of mercury in the environment

is a cumulative effect of natural and anthropogenic sources, each of which contributes to the

global burden of mercury and its related concerns to the health of both the environment and

humans.

The toxicity of mercury and mercury containing compounds has been well documented in

the United States and around the world for decades (World Health Organization 1990, 69). With

the ability to cause damage when ingested, absorbed through the skin or mucous membranes, or

inhaled as a vapor, mercury is a potent toxin that is dangerous to humans and other life forms.

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As a result of this, the United States Environmental Protection Agency (EPA) has set a blood

methyl mercury Reference Dose (RfD) of 5.8 µg/l and a Benchmark Dose Limit (BMDL) of 58

µg/l. The BMDL is the lowest dose or concentration that produces a predetermined change in

incidence of an adverse effect (United States Environmental Protection Agency 2012d).

Determined based on the BMDL, the RfD is an estimate that states a blood concentration

equivalent of the maximum daily oral exposure that is likely to be without a significant risk of

deleterious effects during a lifetime (United States Environmental Protection Agency 2012c).

Where inorganic mercury compounds are not usually toxic to humans, organic compounds, such

as methyl mercury, can cause mild to severe neuromuscular disorders with moderate to severe

exposure (Eccles and Annau 1987, 17-18). Unlike many inorganic compounds, whose

insolubility prevents their absorption through the gastrointestinal tract, methyl mercury is readily

absorbed by the human body when consumed in the diet. In addition, the relatively long half life

of methyl mercury impedes the excretion of the compound, allowing for accumulation within the

human body. To add to the dangers of exposure, methyl mercury is especially toxic because of

its hydrophobic nature, allowing the compound easy transport across various membrane barriers,

such as the blood brain barrier and the placental barrier. In humans and other mammals, every

form of mercury is converted to its mercuric form during the process of excretion. Depending on

the original state of the mercury, this process may happen at different rates. For the compound

methyl mercury, the decomposition of the organic compound is a slow process. As a result of

this, methyl mercury is allowed time to accumulate and circulate throughout the body and

through protective barriers (Eccles and Annau 1987, 17-24).

Although toxic to all humans, methylated mercury is especially dangerous to the fetus

and children, whose developing tissues and nervous systems are particularly vulnerable to the

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effects of the organic compound (World Health Organization 1990, 69). If present in levels

above the RfD, methyl mercury may have disastrous effects on the fetus, due to the ability of the

compound to cross through the placental barrier of the mother and into the womb (Grandjean et

al. 2005, 905-908). In addition, the increased sensitivity of the fetus to methyl mercury may

result in damage to the fetus while the mother remains asymptomatic and unaffected. Once

across the placental barrier, methyl mercury may cause severe damage to the developing nervous

system and brain of the fetus, putting the developing fetus at greater risk for deficits in memory,

learning, sight, hearing, or motor skills. Along with the devastating effects of methyl mercury on

the developing tissue of the fetus, impaired development and maturation of the brain as a result

of fetal exposure may result in the delay of achieving developmental milestones later in life

(Eccles and Annau 1987, 46-47).

Although the negative effects of mercury on humans and the environment had been

established years before, large-scale interest in mercury exposure in the state of Minnesota did

not take shape until 2007 (Patricia McCann, interview by Allison Fast, St. Paul, MN, February

21, 2013). The Environmental Health Division of MDH became interested in mercury exposure

in vulnerable populations, such as pregnant women and children. Seeing health care providers as

an effective way to communicate with women of childbearing age the dangers of mercury

exposure, the Environmental Health Division became interested in collecting concrete data on

mercury exposure levels in the state so health care providers would be more inclined to share this

data with women (McCann, interview). In addition to providing information to women and

families on mercury, there was a statewide and national interest in characterizing the distribution

of mercury exposure. Along with the interest of the Environmental Health Division, the Fish

Consumption Advisory Program of MDH, the EPA, and various Lake Superior regional

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organizations expressed interest in developing a study in which the determinants and distribution

of mercury exposure were investigated. The lack of data on mercury exposure in the state, as

well as the desire to engage the health community in educating the public on mercury exposure,

led to the creation of a regional study in the Lake Superior Basin. The combined interest of

MDH, the EPA, and numerous Lake Superior regional organizations, shaped the initial interest in

mercury exposure to a more regional interest in mercury exposure in women and children. The

various interests of numerous statewide organizations, along with the allocation of funding for a

study in the Lake Superior region on mercury exposure from the EPA, led to the creation of the

Mercury Levels in Blood from Newborns in the Lake Superior Basin study (MN LSB) (McCann,

interview).

Mercury exposure in the state further attracted the attention of the MDH later in 2007

when state legislation mandated a study on mercury exposure be conducted in Minnesota

(Environmental Health Tracking and Biomonitoring 2013). The legislation passed in 2007 was

responsible for the creation of the Environmental Health Tracking Program, along with the

creation of the Biomonitoring Program at MDH. The two programs were then linked to form

EHTB. To provide guidance and recommendations for projects within EHTB, an external

Advisory Panel of experts in public health and environmental science was established (Minn.

Stat. §144.998 2008). Although the Environmental Health Tracking Program and the

Biomonitoring Program were linked, the two programs were established with separate goals.

The ultimate goal of the Environmental Health Tracking Program was to collect and share public

health data in order to identify health priorities that can provide the basis for actions to improve

public health. In contrast, the Biomonitoring program had multiple goals. The first was to

answer questions about the magnitude and range of exposure to specific chemicals in certain

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communities in Minnesota. Other goals were centered on building an infrastructure at MDH for

implementing an ongoing biomonitoring program and building biomonitoring capacity in the

state (Environmental Health Tracking and Biomonitoring 2011). Advancing the capacity of the

Public Health Laboratory to measure chemicals and toxic metals in human hair, blood, and urine,

as well as the development of a baseline for exposures in the state, would allow the

Biomonitoring Program to track progress over time in reducing exposure (Environmental Health

Tracking and Biomonitoring 2013).

In addition to the establishment of EHTB, the 2007 state legislation mandated that four

separate pilot studies be conducted in Minnesota. Each pilot study was to investigate exposure to

various chemicals including arsenic, perfluorinated chemicals, and mercury, in voluntary

populations in the state. Due to funding concerns, EHTB, as well as the Advisory Panel,

explored the possibility of joining a preexisting mercury exposure study (Environmental Health

Tracking and Biomonitoring 2013). At that time, MN LSB was still in its planning stages with

the Fish Consumption Advisory Program of the Environmental Health Division of MDH. In lieu

of conducting a separate mercury biomonitoring study, and out of interest in MN LSB, EHTB

offered their support and some funding to the Environmental Health Division (Minnesota

Department of Health 2008). By the end of the planning stage of MN LSB, EHTB was working

in accordance with the Environmental Health Division to track mercury exposure in newborns in

the Lake Superior Basin.

With funding from the EPA Great Lakes National Program, as well as support and

funding from EHTB, MN LSB began recruiting participants in the fall of 2008. During the

planning phase, various goals were established for the study that reflected the contributions of

both the Environmental Health Division as well as EHTB. Two main goals of the study were to

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measure mercury exposure in a population of newborns in the United States portion of the Lake

Superior Basin, as well as determine characteristics of the exposure in this population

(Environmental Health Tracking and Biomonitoring 2011). Another important goal of MN LSB

was to utilize and evaluate a novel laboratory method for biomonitoring with the use of DBS.

The collection of DBS is a routine newborn screening procedure in hospitals throughout the

country. Requiring only five drops of blood from a newborn’s heel, twenty four to forty eight

hours after birth, the blood is spotted on a filter paper card to be analyzed. Once the sample has

dried, the blood is analyzed in a laboratory to identify newborns at risk for various health

conditions. After analysis, a small amount of blood remains on the filter paper card, so the card

is stored as a residual sample for the future use of the family, the laboratory, and public health

and biomedical research (Genetic Alliance). In MN LSB, this dried blood sample was analyzed

to determine the mercury concentration in Lake Superior Basin newborns. Though not a

common or well-refined method for the measurement of mercury in a newborn blood specimen,

there are various advantages to utilizing DBS over more traditional methods. In addition, the

novel use of DBS in analyzing mercury exposure was an effective way to increase the

biomonitoring capacity of EHTB and the Public Health Laboratory (McCann, interview).

Although a novel and relatively unrefined procedure with no available data for

comparison of results or technique, there are various advantages to the use of DBS. One of the

most common and effective measures of mercury exposure in a newborn is through the analysis

of umbilical cord blood collected after birth (Grandjean et al. 2005, 905-908). Umbilical cord

blood analysis allows for the speciation of the mercury and also has large amounts of published

literature available for comparison of results and technique (Minnesota Department of Health

2013). Although an effective exposure biomarker of mercury, especially methyl mercury for

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which the placenta does not constitute a barrier, the collection of umbilical cord blood requires

trained hospital personnel (Grandjean et al. 2005, 905-908). In addition, the collection of

umbilical cord blood it is not a routine procedure, is costly, and must be done immediately

following birth (Minnesota Department of Health 2013). In comparison, DBS are routinely

collected within forty eight hours after birth, and residual DBS are stored for multitudes of

newborns nationwide after their analysis in newborn screening programs (Genetic Alliance).

Unlike umbilical cord blood, DBS collection is not costly and does not require specially trained

personnel to obtain. Despite this, the use of DBS in biomonitoring is a novel procedure whose

results, technique, and efficacy have not been validated. Additionally, the small quantity of

blood in the sample makes the speciation of mercury impossible (Minnesota Department of

Health 2013). Due to the advantages of DBS to umbilical cord blood and the potential of the

novel procedure to increase the biomonitoring capacity of MDH and the nation, the use of DBS

was an attractive and groundbreaking option for biomonitoring in Minnesota.

The recruitment of Lake Superior Basin newborns for MN LSB began November 2008

and was a collaboration between MDH and state newborn screening programs in Minnesota,

Wisconsin, and Michigan. The geographic boundary of the United States portion of the Lake

Superior Basin was defined by watershed boundary data. Participants were determined based on

this geographic boundary and the zip code of the mother’s residence. Newborns of eligible

participants were identified from the Newborn Screening Database at MDH. Newborns were

excluded from participation if there were complications in the pregnancy, the infant had died or

was born with certain health problems, or the quality of the DBS was insufficient for analysis

(Environmental Health Tracking and Biomonitoring 2011). Local and state public health

departments mailed written communication to mothers of eligible newborns, explaining the

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project and inviting their participation. The written communication consisted of a consent form

and a letter that informed mothers that the specimens would be anonymized, that their individual

babies’ results would not be available, and that MDH would not inform them of the aggregate

findings (McCann 2011). Mothers of eligible newborns were contacted three weeks after giving

birth and invited to participate in the study. If no response was received within three weeks of

the initial communication, a second letter was sent (Environmental Health Tracking and

Biomonitoring 2011). A total of 2,566 parents of eligible newborns were contacted in

Minnesota, inviting their participation in MN LSB and requesting informed consent of the use of

their newborns’ blood. Of these Minnesota parents that were contacted, 1,130 gave their consent

(McCann 2011). Similar methods were utilized in Wisconsin and Michigan to invite mothers of

newborns to participate in the study and acquire informed consent. Of the Wisconsin and

Michigan mothers that were contacted, consent from 140 mothers in Wisconsin and 810 mothers

from Michigan was received. Due to funding concerns and issues with the storage and custody

of DBS in Michigan specimens, the number of specimens from Michigan was reduced from 810

to 200 (McCann 2011). The recruitment of participants continued until November 2010, when

the beginning stages of data collection and specimen analysis began.

The results of MN LSB revealed a wide range of total mercury concentrations, with the

majority of specimens exhibiting low mercury levels. Of the 1,470 parents that had given

informed consent, the total number of specimens analyzed was 1,465, with 1,126 specimens

from Minnesota, 139 from Wisconsin, and 200 from Michigan (McCann 2011). After the

recruitment of participants concluded in 2010, data collection and analysis began and continued

until its conclusion in the fall of 2011. The analysis of the total mercury concentration in the

1,465 specimens showed forty three percent of the specimens to be below the method detection

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limit (MDL) of 0.7 µg/l, indicating a low or nonexistent mercury concentration in nearly half the

specimens (McCann 2011). About one percent of the specimens were found to be above the

BMDL of 58 µg/l, with eight percent of specimens above the RfD of 5.8 µg/l. Of the blood

mercury concentrations that exceeded the RfD, Minnesota had the highest rate at ten percent of

the 1,126 specimens exceeding a blood mercury concentration of 5.8 µg/l. In comparison to the

Wisconsin and Michigan specimens, three percent of the 139 Wisconsin specimens, and none of

the 200 Michigan specimens, exceeded the RfD (Myers 2012). The maximum exposure

measured was 211 µg/l (McCann 2011). The results depicted a trend of higher mercury exposure

in Minnesota specimens as well as an exposure pattern with highest mercury concentrations in

the summer births. The seasonal exposure pattern with highest mercury concentrations in

summer births supports a local fish consumption exposure pathway. Despite this clear pattern, it

is impossible to validate a fish consumption exposure pathway without the ability to speciate

mercury in DBS analysis. In addition, the analysis of DBS only enabled the detection of

mercury when it exceeded the MDL, limiting the characterization of low exposure levels

(McCann 2011). As a result of this and other challenges, the findings of MN LSB raised

questions from researchers and MDH about the exposure pathway, as well as the distribution and

characteristics of mercury exposure in the Lake Superior Basin and throughout the state of

Minnesota. In addition, the uncertainty surrounding the use of DBS raised questions about the

validity of the laboratory method and the efficacy of DBS as an indicator of mercury exposure in

newborns (Environmental Health Tracking and Biomonitoring 2013).

The multiple challenges of MN LSB and recommendations from MDH Advisory Panel

led to various goals and plans to conduct further research on mercury exposure in Minnesota.

The results of MN LSB that showed ten percent of Minnesota specimens had a mercury

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concentration in their blood that exceeded the EPA RfD of 5.8 µg/l sparked interest in additional

biomonitoring and raised questions on the limitations of the study. The results of MN LSB were

limited to babies born to mothers who gave their consent and were living in the Lake Superior

Basin area of Minnesota, Wisconsin, and Michigan. Because of this, the sample was biased and

therefore was not necessarily representative of a statewide distribution of mercury. In addition,

the MN LSB sample did not take into account that some Minnesota communities may be more

exposed than others due to geographic, cultural, or ethnic differences. The MN LSB sample

lacked the ability to characterize mercury exposure on a statewide level and shed light on any

potential disparities in vulnerability or exposure to mercury in various populations in Minnesota.

Another challenge of MN LSB was the lack of MDH data on vulnerable groups, as well as any

statewide or national data available for comparison of mercury exposure in newborns

(Environmental Health Tracking and Biomonitoring 2013). The DBS analysis data lacked

published literature or data for comparison of methods and results of mercury levels in newborn

blood. In addition, the laboratory method used for analysis was a novel method that had not

been validated or peer reviewed (McCann 2011). The uncertainty of laboratory results and

methods, along with the absence of data or published literature for comparison, led to questions

on the accuracy of the use of DBS as an indicator of newborn mercury exposure.

The analysis of newborn blood in MN LSB effectively identified a public health issue

that required more action and investigation in Minnesota. In addition, the use of DBS as a

potential biomonitoring method generated interest in MDH, and specifically the Public Health

Laboratory, in further statewide biomonitoring of mercury. Because of the questions that were

raised on the characteristics of mercury exposure on a wider scale, the MDH Advisory Panel

made various recommendations for additional biomonitoring. First, the Advisory Panel

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recommended additional biomonitoring in newborns be done at a statewide level in order to

identify disparities in exposure and to provide a baseline for tracking progress in vulnerable

populations. In addition, the Advisory Panel recommended subsequent biomonitoring be done to

validate the fish consumption exposure pathway, identify additional sources of mercury

exposure, and refine methods for mercury biomonitoring in Minnesota. To confirm DBS as an

accurate indicator of mercury exposure in newborns, the Advisory Panel recommended further

research be conducted in which the results of DBS analysis be compared to a traditional measure

of mercury concentration in newborns (Environmental Health Tracking and Biomonitoring

2013).

With MDH Advisory Panel recommendations in mind, additional mercury biomonitoring

began in Minnesota in 2012 with three separate initiatives. The first was a collaboration of the

MDH Biomonitoring Program and the University of Minnesota in the Pregnancy and Newborns

Exposure Study (Minnesota Department of Health 2012b). The second is a planned

collaboration of EHTB with the former National Children’s Study (NCS) South Dakota State

University Vanguard pilot study in the Minnesota National Children’s Study (NCS) Newborn

Mercury Project (Minnesota Department of Health 2013d). The third study was the Fond du Lac

(FDL) Community Biomonitoring Study, which is part of the Great Lakes Restoration Initiative

(GLRI). This study was a collaboration of MDH with the FDL Band of Lake Superior Chippewa

(Minnesota Department of Health 2013a). Although different in various respects, each study

was designed to further statewide mercury biomonitoring, identify disparities in mercury

exposure in vulnerable populations, and refine and validate the use of DBS analysis as an

indicator of newborn mercury exposure (Environmental Health Tracking and Biomonitoring

2013).

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The Pregnancy and Newborns Exposure Study compared mercury levels in paired

newborn umbilical cord blood and DBS specimens. The study recruited participants already

enrolled in a larger study being conducted in part at the University of Minnesota, called The

Infant Development and Environmental Study (TIDES) (Minnesota Department of Health

2012b). A four year, National Institutes of Health-funded project, TIDES focused on exploring

the effects of various exposures on infants during gestation at research sites in Minnesota, New

York State, Washington, and California (Minnesota Department of Health 2012b). The

Pregnancy and Newborns Exposure Study began recruiting University of Minnesota TIDES

participants in June 2012 with the goal of addressing various questions raised by MN LSB

results (Minnesota Department of Health 2012a). In response to MN LSB results, and

recommendations made by MDH Advisory Panel, the Pregnancy and Newborns Exposure Study

progressed with three main goals. The first goal was to compare total mercury content in paired

umbilical cord blood and DBS in order to obtain a measure of the ratio of mercury concentration

between the whole blood and DBS paired samples. Due to the inability of DBS analysis to

speciate mercury as either organic or inorganic, the second goal of the study was to speciate

mercury in the umbilical cord blood specimens. The final goal of the Pregnancy and Newborns

Exposure Study was to further refine laboratory methods for measuring mercury exposure in

newborns (Minnesota Department of Health 2012b).

Beginning in June 2012 and lasting until January 2013, informed consent was obtained

from forty nine women currently enrolled in University of Minnesota TIDES (Minnesota

Department of Health 2013d). After recruitment had concluded, data collection began with the

obtainment of forty nine matched pairs of infant umbilical cord blood and DBS specimens,

collected after birth by hospital staff. After collection, specimens were sent to the Public Health

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Laboratory to begin data analysis. Analysis of umbilical cord blood specimens for total mercury,

lead, and cadmium concentration in each of the forty nine samples was concluded in March

2013. Analysis revealed one specimen with a mercury concentration greater than the RfD, and

no specimens that exceeded the RfD for lead (Minnesota Department of Health 2013d).

Currently, results letters are being prepared and mailed to the participants, dictating

individualized results. With the analysis of total mercury concentration in umbilical cord blood

specimens complete, the next steps of the Pregnancy and Newborns Exposure Study are to

analyze the DBS for total mercury content and to speciate the mercury in the umbilical cord

blood (Minnesota Department of Health 2013d). After the completion of data analysis, the next

steps for the Pregnancy and Newborns Exposure Study are to formulate long term goals of

pursuing additional mercury research on the extent of exposure in various populations in

Minnesota. Additional long term goals include investigation of additional sources of mercury

exposure statewide and the refinement of laboratory methods involving DBS (Minnesota

Department of Health 2012a).

The Minnesota NCS Newborn Mercury Project will compare matched specimens of

umbilical cord blood spot, DBS, whole umbilical cord blood, and maternal blood (Minnesota

Department of Health 2013d). In addition, the project will provide added data to the Pregnancy

and Newborns Exposure Study, in order to increase the sample size for analysis of the

comparison of matched blood specimens. Utilizing previously collected specimens of umbilical

cord blood, DBS, and maternal blood from the former NCS South Dakota State University

Vanguard pilot study, EHTB will obtain and analyze the matched specimens in order to

accomplish three main biomonitoring goals. The first goal of the Minnesota NCS Newborn

Mercury Project is to assess the comparability of different measures of prenatal exposure to

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mercury. Based on the desire to validate the use of DBS as an effective biomonitoring tool for

mercury, the second goal is to compare paired whole umbilical cord blood and umbilical cord

blood spot mercury levels to determine how accurately mercury levels in blood spots reflect

levels in the original, whole blood sample. The final goal of the Minnesota NCS Newborn

Mercury Project is to explore the extent of newborn mercury exposure on a statewide level in

order to determine if the elevated mercury levels found in MN LSB were applicable to other

parts of Minnesota. Upon completion of data collection and analysis, results of the Minnesota

NCS Newborn Mercury Project will be compared to the results of other mercury biomonitoring

research. Due to the very limited availability of published literature and data on newborn

mercury exposure, comparison of newborn mercury levels and blood analysis methods will

likely be restricted to the MN LSB and the Pregnancy and Newborns Exposure Study data for

comparison (Minnesota Department of Health 2013d).

The FDL Community Biomonitoring Study is a part of the GLRI that was enabled in

2010 by a grant from the EPA (United States Environmental Protection Agency 2012b). The

study was a collaboration of MDH with the FDL Band of Lake Superior Chippewa (Minnesota

Department of Health 2013a). The Fond du Lac Community Biomonitoring Study was enabled

by an additional EPA grant that was awarded to MDH in 2012 to reduce mercury exposure risk

for women and children who live along Lake Superior’s north shore (United States

Environmental Protection Agency 2012a). The study is conducting biomonitoring in non-

pregnant, adult Native Americans that have been residents of northeast Minnesota for at least the

past twelve months. The purpose of the FDL Community Biomonitoring Study is to explore the

characteristics of mercury exposure in a vulnerable population and to compare these results to

the general population (Minnesota Department of Health 2013a). In collaboration with GLRI,

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the FDL Community Biomonitoring Study developed goals for improving health screening in the

community and forming more effective fish consumption advisories (United States

Environmental Protection Agency 2012a). Beginning in December 2012, letters and consent

form were mailed to potential participants, describing the study and inviting their participation.

Due to increased community interest in the study, outreach and recruitment campaigns have been

largely successful. As of February 2013, fifty five participants had enrolled in the study. With

the increased levels of community interest, participation recruitment is expected to enroll many

more participants by the end of recruitment in the fall of 2013. In addition to the biomonitoring

of other vulnerable populations, such as pregnant women and babies, the FDL Community

Biomonitoring Study is another piece to the puzzle in identifying vulnerable groups in Minnesota

who may have a higher risk of mercury exposure (Minnesota Department of Health 2013a).

Beginning in 2007 with the creation of EHTB and its related Advisory Panel, the

exploration of mercury exposure in Minnesota has experienced a statewide increase in attention

and interest. The results of MN LSB that showed elevated mercury concentrations in ten percent

of Minnesota Lake Superior Basin newborn specimens captured the attention of local and

national government organizations, health care providers, and the public. Along with increasing

the visibility and recognition of mercury exposure as an important issue in Minnesota health, the

results of MN LSB kindled interest in the further characterization and exploration of mercury

exposure in other vulnerable populations, as well as the general population statewide. Through

its innovative use of DBS, the novel laboratory method used in MN LSB increased the visibility

of mercury exposure in the state, as well as the biomonitoring capacity of the Public Health

Laboratory and MDH. The cultivation of further exploration into the distribution, exposure

pathways, and methods of measuring and analyzing mercury exposure in Minnesota allowed for

20

additional mercury biomonitoring studies and intervention projects to be undertaken. The

continued interest in mercury exposure that has been demonstrated by the Pregnancy and

Newborns Exposure Study, the Minnesota NCS Newborn Mercury Project, and the FDL

Community Biomonitoring Study, illustrates a biomonitoring program that is continually

interested in the health and wellbeing of both the population and environment of the state.

Through continued health exposure education and intervention efforts, the efforts of MDH have

increased community and health care provider awareness to the dangers of mercury exposure.

Although further research, intervention efforts, and increased concern for environmental mercury

contamination are necessary, MDH and EHTB are effectively diminishing levels of human

mercury exposure throughout the state of Minnesota. The further characterization of mercury

exposure and understanding of exposure pathways will increase the efficacy of community

education and intervention projects, decreasing the harmful exposure of individuals to mercury

and fostering the health of communities in Minnesota.

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