protecttrainees-blog

[protecttrainees-blog]

PROTECT project 4: Phthalates and CVOCs studies in the karst region of Puerto Rico

Jonathan Toro, Eduardo Alvarez, Marvic Carmona

The underground environment is composed of a wide variety of minerals, soil, and rocks formed by their deposition millions of years ago. During their formation procedure, these underground environments developed heterogeneous layers and voids between rocks and minerals within these subsurface regions. Depending on your geographical location, these layers can exist as a combination of permeable rocks, fractures, and unconsolidated material including gravel, sand, and silt. These heterogeneous characteristics allow water to infiltrate from the surface reaching the subsurface region ending into aquifers. An aquifer is a compartment beneath ground formed by the combination of the underground layers and voids, which permit to accumulate and supply the water retained in voids between rocks, soil, and sediments known as groundwater. Aquifers can provide great storage capacity and transport large amounts of groundwater to supply freshwater such as in karst environments.

Karst aquifers are sedimentary soluble rocks, primarily limestone and dolomite, which undergo by dissolution creating distinctive surface and subsurface features associated with sinkholes, pores, fractures, conduits, caves, and springs. Karst aquifers are a continuously changing system underlying about 20% of the planet’s ice-free continental areas, providing 20-25% of the global population’s water needs (Ford and Williams, 2007).  In the United States of America (USA), karst systems underlay about 18% of the continent (Weary and Doctor, 2014) and provide over 40% of the groundwater used for drinking purposes (Veni et al., 2001). In Puerto Rico, 50% of the supplied groundwater comes from karst aquifers (Carmona and Padilla, 2015).

As highly permeable landscape, most of the runoff directly drains into the karst underground by sinkholes drains, sinking streams and infiltration. This direct input may cause that contaminants can easily travel into the karst aquifers (Vesper et al., 2003). Therefore, it is important to emphasize that karst aquifers serve as a significant source of freshwater, but also due to its high vulnerability to contamination makes it a potential route of exposure to hazardous chemical compounds. Indeed, we have encountered extensive contamination in karst groundwater such as in the northern karst region of Puerto Rico.

In Puerto Rico, there have been more than 200 contaminated sites and has had 23 historical superfund sites since 1981 of which over more than 50% are in the northern karst (Carmona and Padilla, 2016). Additional to the extensive contaminated sites, Puerto Rico has been indicated as the highest rate of preterm birth among USA. The Puerto Rico Testsite for Exploring Contaminated Threats (PROTECT) have been working to understand the potential relationship between the groundwater contamination and preterm birth. The goal of PROTECT is to employ an integrated, cross-disciplinary approach to study fate, and transport processes, exposure, health impact and remediation of hazardous contaminants, such as phthalates and chlorinated volatile organic compounds (CVOCs) as potential agents of high preterm birth rates in the island. To achieve this goal, PROTECT encompasses 5 research projects, and 6 cores. Our research group represents project 4, and our goal is to study and understand the fate, transport and exposure pathways of contaminants in karst groundwater systems, particularly in the northern karst region of Puerto Rico.  Our study area includes the municipalities of Arecibo, Barceloneta, Florida, Manatí, Vega Baja, Vega Alta, Toa Baja, and Dorado.

Project 4 focuses to understand the fundamental knowledge of fate and transport mechanisms to characterize, quantify, and statistically model the spatiotemporal contaminants distribution in karst systems. To do so, studies are conducted in karstified laboratory-scale physical models that might represent the actual system and understand these transport processes that dominate within karst. This methodology will lead to the development of computing models that could provide a representation of what is actually occurring in the northern karst region. Our project also collects historical data from government and federal agencies of phthalates and CVOCs to develop historical spatiotemporal distributions of the contaminants within the study area. Furthermore, groundwater and tap water sampling and chemical analysis are conducted from the study area to assess the presence of these contaminants and develop spatiotemporal distributions. The historical and current data is organized and uploaded to a database to keep record, conduct the spatiotemporal distribution maps, and provide access to the rest of the projects of PROTECT for further analysis to find the relationship of the groundwater contamination with preterm birth in the island.

The laboratory-scale models include a small and intermediate confined limestone physical models that were built to represent a controlled karstified aquifers. Transport experiments involve the injection of multiple tracers and dense non-aqueous phase liquids to assess fate and transport processes. Multiple tracer experiments contribute to define the groundwater pathways within karst under different flow rates. Experiments using dense non-aqueous such as Trichloroethylene brings a better understanding of the fate and transport processes that involves from actual hazardous pollutants within this highly heterogeneous system that is karst. Furthermore, the experiments conducted at a different scale might provide the scale dependence to understand the dynamics at a regional scale. The development of models from these experiments will improve to predict fate and transport of contaminants within karst systems that could lead to reduce impacts to the environment and human health.

It is essential to recall that karst environments are very important freshwater resources for human consumption and ecological integrity. Is our responsibility as scientists but most importantly as human beings to protect and preserves our natural resources for the wellbeing of humanity.

References         

Ford D.C., and P. Williams. 2007. Karst Hydrogeology and Geomorphology. 2nd ed. Chichester. England: John Wiley & Sons.

Veni, G., DuChene, H., Crawford, N.C., Groves, C.G., Huppert, G.N., Kastning, E.H., Olson, R., and Wheeler, B.J., 2001. Living with Karst—A Fragile Foundation: Alexandria, Virginia, American Geological Institute Environmental Awareness Series 4, 64 p.

Vesper, D.J., C.M.  Loop, and W.B. White. 2003. Contaminant transport in karst aquifers. Speleogenesis and Evolution of Karst Aquifers. 13-14:101-111.

Carmona, M., I.Y. Padilla, K. Anderson and P. Torres. 2016. Use of Passive Sampler Devices for Deployment and Sampling Spring Water in the Northern Karst Aquifer of Puerto Rico.  Environmental, Health and Science Fest 2016 Oral Presentation, Durham NC, December 5-8, 2016.

Carmona, M. and I.Y. Padilla. 2015. Resilience of DNAPL in Karst Systems. Superfund Research Program Annual Meeting 2015 Poster Presentation, San Juan PR, November 18-20, 2015. �{0�7�5�[��

[protecttrainees-blog]

Introducing…PROTECT Project 2: Pollutant Activation of Cell Pathways in Gestational Tissues

By Elana Elkin,

PhD Candidate in the Loch-Caruso Reproductive Toxicology Lab, University of Michigan 

Trichloroethylene: An Environmental Contaminant of Interest

Trichloroethylene (TCE) is a solvent most commonly used as a metal degreaser to clean machine parts in industrial manufacturing. TCE, is a common environmental contaminant found in approximately 800 Environmental Protection Agency-designated, hazardously contaminated Superfund Sites. Despite being classified as a “known human carcinogen” approximately 2.4 million pounds of TCE were released into the environment in 2010. As a result of its continued use and widespread persistent environmental contamination, TCE exposure continues to pose a threat to human health in both environmental and occupational capacities.

 The Placenta: The Organ of Life for Unborn Babies

The word placenta comes from the Latin words plakous or plakount meaning “flat cake.” The placenta is an amazingly complex organ that is adapted to carry out multiple functions vital to the survival and growth of an unborn baby. The placenta performs oxygen, nutrients and metabolic waste exchange, offers immune protections, synthesizes crucial signaling hormones and metabolizes chemicals.  Any abnormalities in the development or functional capacity of the placenta throughout pregnancy can lead to detrimental short-term and long-term health consequences for the baby. For example, a damaged or abnormal placenta can lead to miscarriage, preterm birth, low birth weight or small-for-gestational-age. Each of these birth outcomes increases the risk for neurodevelopmental deficiencies, asthma, immune system deficiencies, cardiovascular issues, and hearing and vision problems. Due to the role that the placenta plays in successful pregnancy outcomes, our lab primarily focuses on determining how exposure to environmental contaminants can cause damage to the placenta.

 Recent Findings from Our Lab

When environmental contaminants enter the human body, the body tends to chemically breakdown those compounds into metabolites - a process known as metabolism. Often times, metabolites are more harmful to the body than the original compound. Recently, our lab was able to demonstrate that exposure to the TCE metabolite S-(1, 2-dichlorovinyl)-L-cysteine (DCVC) causes a specific type of cell death called apoptosis in a type of placental cell that is vital to its development early in pregnancy. The implications of this finding are important because its offers a direct link between exposure to the metabolite and cellular damage, an important step in the process of proving that TCE causes pregnancy complications and poor birth outcomes. Building upon our recent finding about apoptosis in placental cells, we are currently studying how DCVC induces apoptosis within the cell. For information about our lab can be found at our website: https://sites.google.com/a/umich.edu/lochcaruso-lab/

[protecttrainees-blog]

The Effect of Chemical Exposure on Preterm Birth

Amira Aker

What is preterm birth, and why does it matter?

A healthy pregnancy typically lasts around 40 weeks. Preterm birth is the medical term used by doctors when a baby is born early- or before 37 weeks. When a baby is born too early, there could be complications. For example, the lungs are usually the last organ in the body to form, so a preterm baby may have difficulty breathing on its own for the first few weeks of its life. Scientists have also discovered that preterm babies are also more likely to have neurological disabilities, vision problems, hearing impairment, breathing problems, and chronic diseases later in life (Blencowe et al., 2013; Centers for Disease Control and Prevention, 2015; Luu, Katz, Leeson, Thébaud, & Nuyt, 2015; Marlow, Wolke, Bracewell, & Samara, 2005). So it’s important for us to try to understand why some babies are born early to be able to prevent complications throughout their lives.

We theorized that increased exposure to certain chemicals may lead to preterm birth. Some chemicals we’re exposed to look like our hormones. Hormones act like a messenger in your body. Your organs are constantly talking to each other, and they send each other “messages” by raising or lowering the level of a hormone, which turns a process in your body on and off. Therefore, if a chemical enters your body, and looks like one of your hormones, it may trick your body to turning things on or off. We call these chemicals, endocrine disruptors. Humans are pretty good at keeping things controlled and recognizing the “foreign” chemicals from our actual hormones, but pregnancy is a very sensitive time because there are a lot of changes happening in the mother and the growing baby, which may increase the rate of mistakes.

Our research

The first step was to recruit pregnant women into the study and follow them until they give birth. As we waited for the women we recruited to give birth (and study our main outcome of interest, preterm birth), our team has focused on collecting data that may be related to preterm birth. The topics will be described below, but generally, our team has focused on three main topics: 1) the exposure levels of various chemical classes in our study participants as compared to the rest of the US; 2) the effect of those chemicals on a range of reproductive and thyroid hormones during pregnancy; and 3) the effect of those chemicals in a range of inflammatory markers.

We collected urine and blood samples from the pregnant women at three different time points during pregnancy to get an idea of how certain chemicals and biological processes may increase and/or decrease over pregnancy. From the urine, we measured a wide range of chemicals suspected to be endocrine disrupting, including phenols, phthalates, and pesticides. Phenols can be found in consumer products like shampoo, soap, sun screen and the like, while phthalates can also be found in some creams and shampoos, as well as, food packaging and toys. In general, most of the pesticides were lower among this cohort compared to women of comparable age in the rest of the US (Lewis et al., 2014, 2015). On the other hand, levels of phenols and phthalates in our cohort were either similar to, or higher than the levels of women of comparable age in the rest of the US (Cantonwine et al., 2014; Meeker et al., 2013).

The next step was to see if any of these chemicals are related to biological indicators. Previous research had linked endocrine disruptors to changes in hormone levels and induced inflammation (NIEHS, n.d.). So we looked at a range of reproductive and thyroid hormone levels from blood samples, and compared them to the levels of exposures measured at the same time points. We found that some phenols and phthalates were negatively associated with progesterone (Aker et al., 2016; Johns et al., 2015). We also detected associations between phenols and phthalates and thyroid hormones. Interestingly, we found that the association between the chemical and the hormone sometimes depended on the time point. For example, some phthalates only showed strong associations with thyroid hormones towards the third trimester, but not the second trimester (Johns et al., 2015). The association of some phenols and estradiol even flipped directions from one time point to the other (Aker et al., 2016).

Inflammation is a complex system that is initiated by the body when it enters defense mode. Previous studies have showed that some types of preterm birth may be related to increased inflammation around the fetus (McElrath et al., 2008). Studies have also showed that some environmental chemicals, like air pollution, can induce inflammation (Grunig et al., 2014). Therefore, we looked to see if an increase in chemical exposure lead to an increase in inflammation. We found evidence of a relationship between phenols and inflammation (Watkins et al., 2015), but no significant relationship between phthalates and inflammation (Ferguson et al., 2014). We did, however, find strong evidence for increased oxidative stress with exposure to phenols and phthalates. When a body tries to repair damage, it can release certain products called reactive oxygen species (ROS). ROS can damage components of a cell, which could lead to a host of adverse effects and diseases like cancer, diabetes or autism (Mittal, Siddiqui, Tran, Reddy, & Malik, 2014; Napoli, Wong, & Giulivi, 2013). If the body is unable to detoxify these ROS sufficiently, this is referred to as oxidative stress. The fact that we found an association between oxidative stress and our exposures could indicate a potential pathway for disease or adverse outcomes during pregnancy.

The next step will be to look for the association of these exposure to preterm birth, and check if either of these pathways (hormone level altering or increased inflammation/oxidative stress) are leading to the increase in preterm birth. It has been very exciting to work on this project, and we hope this research will finally be able to answer some questions!

 References

Aker, A. M., Watkins, D. J., Johns, L. E., Ferguson, K. K., Soldin, O. P., Anzalota Del Toro, L. V., … Meeker, J. D. (2016). Phenols and parabens in relation to reproductive and thyroid hormones in pregnant women. Environmental Research, 151, 30–37. 

Blencowe, H., Cousens, S., Chou, D., Oestergaard, M., Say, L., Moller, A.-B., … Lawn, J. (2013). Born Too Soon: The global epidemiology of 15 million preterm births. Reproductive Health, 10(Suppl 1), S2. 

Cantonwine, D. E., Cordero, J. F., Rivera-González, L. O., Anzalota Del Toro, L. V., Ferguson, K. K., Mukherjee, B., … Meeker, J. D. (2014). Urinary phthalate metabolite concentrations among pregnant women in Northern Puerto Rico: Distribution, temporal variability, and predictors. Environment International, 62, 1–11. 

Centers for Disease Control and Prevention. (2015, December 4). Preterm Birth | Maternal and Infant Health | Reproductive Health | CDC. Retrieved February 8, 2016, from http://www.cdc.gov/reproductivehealth/maternalinfanthealth/pretermbirth.htm

Ferguson, K. K., Cantonwine, D. E., Rivera-González, L. O., Loch-Caruso, R., Mukherjee, B., Anzalota Del Toro, L. V., … Meeker, J. D. (2014). Urinary phthalate metabolite associations with biomarkers of inflammation and oxidative stress across pregnancy in Puerto Rico. Environmental Science & Technology, 48(12), 7018–7025. 

Grunig, G., Marsh, L. M., Esmaeil, N., Jackson, K., Gordon, T., Reibman, J., … Park, S.-H. (2014). Perspective: ambient air pollution: inflammatory response and effects on the lung’s vasculature. Pulmonary Circulation, 4(1), 25–35. 

Johns, L. E., Ferguson, K. K., Soldin, O. P., Cantonwine, D. E., Rivera-González, L. O., Toro, L. V. A. D., … Meeker, J. D. (2015). Urinary phthalate metabolites in relation to maternal serum thyroid and sex hormone levels during pregnancy: a longitudinal analysis. Reproductive Biology and Endocrinology, 13(1), 4. 

Lewis, R. C., Cantonwine, D. E., Anzalota Del Toro, L. V., Calafat, A. M., Valentin-Blasini, L., Davis, M. D., … Meeker, J. D. (2014). Urinary biomarkers of exposure to insecticides, herbicides, and one insect repellent among pregnant women in Puerto Rico. Environmental Health: A Global Access Science Source, 13, 97. 

Lewis, R. C., Cantonwine, D. E., Del Toro, L. V. A., Calafat, A. M., Valentin-Blasini, L., Davis, M. D., … Meeker, J. D. (2015). Distribution and determinants of urinary biomarkers of exposure to organophosphate insecticides in Puerto Rican pregnant women. The Science of the Total Environment, 512-513, 337–344. 

Luu, T. M., Katz, S. L., Leeson, P., Thébaud, B., & Nuyt, A.-M. (2015). Preterm birth: risk factor for early-onset chronic diseases. CMAJ: Canadian Medical Association Journal = Journal de l’Association Medicale Canadienne. 

Marlow, N., Wolke, D., Bracewell, M. A., & Samara, M. (2005). Neurologic and Developmental Disability at Six Years of Age after Extremely Preterm Birth. New England Journal of Medicine, 352(1), 9–19. 

McElrath, T. F., Hecht, J. L., Dammann, O., Boggess, K., Onderdonk, A., Markenson, G., … ELGAN Study Investigators. (2008). Pregnancy disorders that lead to delivery before the 28th week of gestation: an epidemiologic approach to classification. American Journal of Epidemiology, 168(9), 980–989. 

Meeker, J. D., Cantonwine, D. E., Rivera-González, L. O., Ferguson, K. K., Mukherjee, B., Calafat, A. M., … Cordero, J. F. (2013). Distribution, variability, and predictors of urinary concentrations of phenols and parabens among pregnant women in Puerto Rico. Environmental Science & Technology, 47(7), 3439–3447. 

Mittal, M., Siddiqui, M. R., Tran, K., Reddy, S. P., & Malik, A. B. (2014). Reactive Oxygen Species in Inflammation and Tissue Injury. Antioxidants & Redox Signaling, 20(7), 1126–1167. 

Napoli, E., Wong, S., & Giulivi, C. (2013). Evidence of reactive oxygen species-mediated damage to mitochondrial DNA in children with typical autism. Molecular Autism, 4, 2.

NIEHS. (n.d.). Endocrine Disruptors. Retrieved January 16, 2017, from https://www.niehs.nih.gov/health/topics/agents/endocrine/

Watkins, D. J., Ferguson, K. K., Anzalota Del Toro, L. V., Alshawabkeh, A. N., Cordero, J. F., & Meeker, J. D. (2015). Associations between urinary phenol and paraben concentrations and markers of oxidative stress and inflammation among pregnant women in Puerto Rico. International Journal of Hygiene and Environmental Health, 218(2), 212–219. 

  �sj��

[protecttrainees-blog]

Modeling and Groundwater Remediation

Shirin Hojabri

Why groundwater?

Groundwater is an essential source of drinking water because of its availability as well as its reliability and good quality [1]. More than 1.5 billion people worldwide and more than 50% of the population of the United States rely on groundwater as their primary source of drinking water [2]. Concern about the health risks associated with groundwater pollution have led to the enhancement of federal and state laws regulating the use, storage and transport of hazardous substances, as well as establishing human exposure limits [3].

"The human right to water entitles everyone to sufficient, safe, acceptable, physically accessible and affordable water for personal and domestic uses", UN CESC - General Comment 15, para.2. Although, I would change this statement a little and say “this is the right for all beings on earth” instead of only “humans” - we as humans forget this often.

This statement was published by United Nations Committee on Economic, Social and Cultural Rights (CESC), which is motivation for all mankind to reduce water use and pollution, scientists to better understand the influences of contamination on human health and the ecosystems and develop efficient and cost effective remediation technologies, and for politicians to enforce more laws to protect this “right and need.”

So what to do with contaminated groundwater?

There is a variety of cleanup methods for a remedy of groundwater at a site, however the efficiency and cost of these options may vary widely. Conventional treatment of groundwater includes pumping groundwater to the land surface followed by treatment and engineered disposal or injecting chemicals directly to the source zone or using reactive barriers in the path of flowing groundwater. In some cases, these remediation technologies are not efficient, can be expensive and time consuming.

How about using electricity to degrade pollutants in groundwater?

Stepping back from the conventional remediation technologies, elelctroremediation (electrochemical degradation) is promising in situ (on site) soil and groundwater remediation method, particularly for contaminated fine grained sites. Electroremediation gained increasing attention since 1990s because of its low energy consumption accompanied by low maintenance and an easy control of conditions responsible for contaminants transformation. Additionally, a great advantage of electroremediation is the opportunity of substituting the conventional remediation energy source with a renewable source of energy (e.g. solar power). The process uses direct electric current across electrodes immersed in groundwater to intercept and transform contaminants through direct and/or indirect oxidation or reduction reactions [4]. 

As for any other remediation technique, electroremediation needs to be engineered for different site conditions and achieve required groundwater quality after treatment. And as our research group move forward from the development of the electrochemical systems in laboratory scale to field application of the technology, applying mathematical models is a powerful tool.

Mathematical models: how can they help with groundwater protection?

Even though we may think that all the phenomena in the universe are extremely complicated and unpredictable, there are certain rules for them all! We can define each phenomenon through mathematical equations and create mathematical models to predict certain behaviors! For example if you hear someone talking about a certain fluid flow, you can find the describing mathematical equation in order to define the flow rate, the species that it can transport, the shape of the flow, the shape of the sediment and etc.

Concerns about groundwater contamination have been motivated the development of numerous simulation models for groundwater quality management in the recent years. The mathematical models provide a good estimate of energy use, and therefore play an important role in evaluating the cost efficiency of the remediation process. Mathematical models have been used to help us understand the subsurface water flow and contaminant transport phenomena.

Our mathematical models have been developed so we can better understand multicomponent species transport mechanisms in electrochemical systems which are needed for development of treatment design or analysis tools for the implementation of electroremediation.

We completed our model by arranging the dominant mathematical equations to explain our system. We compared the results of our model with an experimental data from our lab scale experiment in order to identify the missing mechanisms. In the beginning, it was challenging to identify these mismatches but eventually we were able to develop models that predict the changes of certain conditions in water due to electrochemical processes. By each step our models are getting closer to predict performance of our systems for our final goal, which is implementation!

 References:

[1] Moody, D.W., Groundwater Contamination in the United-States. Journal of Soil and Water Conservation, 1990. 45(2): p. 170-179.

[2] Alley, W.M., et al., Hydrology - Flow and storage in groundwater systems. Science, 2002. 296(5575): p. 1985-1990.

[3] Harman, W.A., C.J. Allan, and R.D. Forsythe, Assessment of potential groundwater contamination sources in a wellhead protection area. Journal of Environmental Management, 2001. 62(3): p. 271-282.

[4] Panizza, M. and G. Cerisola, Direct and mediated anodic oxidation of organic pollutants. Chem Rev, 2009. 109(12): p. 6541-69.

[5] Acar, Y.B. and A.N. Alshawabkeh, Principles of Electrokinetic Remediation. Environmental Science & Technology, 1993. 27(13): p. 2638-+.

[6] Yeh, G.T. and V.S. Tripathi, A Model for Simulating Transport of Reactive Multispecies Components - Model Development and Demonstration. Water Resources Research, 1991. 27(12): p. 3075-3094.

","las�K��zL�