Investigating the occurrence of contaminants in tap water relative to flood zone status in the “Big Easy”

C. Nacaya Brown

1. Overview

Tap water is abundantly available in the USA. However, the quality of the water consumed can vary depending on environmental factors such as proximity to industrial operations, insufficient maintenance of conduits, or substandard environmental hygiene practices.^1-3 Recent studies have discovered harmful substances such as legacy toxins, PFAS, PAHs, heavy metals, and microbial contaminants which can lead to waterborne illnesses in susceptible populations including the elderly and children.^5-7 Common sources of contamination include accidental or perpetual release of contaminants directly into the environment.^1-3 We are interested in understanding the passive introduction of contaminants into tap water via flooding in the Greater New Orleans area its impact on water quality. Acts of nature like Hurricane Katrina or heavy rain fall cause flooding in vulnerable parts of the city (see Figure 1) which can introduce contaminants indirectly.^8-9 This pilot study will investigate correlations between the frequency of flooding in the Greater New Orleans area and the quality of tap water in respective flood zones via non-targeted analytical analyses.

Hypothesis: Urban areas that are prone to flooding will demonstrate an increased occurrence of tap water contamination.

The results of this pilot study will serve as the foundation for future projects. The proposed length of the pilot is 11 months. Results will be shared via manuscript submission to an open access journal and Researchhub.com

Figure 1: City of New Orleans Flood Map 2025. Areas prone to flooding are highlighted in blue.

2. Introduction

Access to clean tap water for drinking, washing, and cooking are extremely important in urban cities like New Orleans, Louisiana and others. New Orleanians take pride in the culture, music, and history of our city. Culinary staples like gumbo, red beans and rice, and boiled seafood are local favorites that require water to cook and the use of tap water is a cost-effective way to cook our favorite foods. However, boiling can increase the concentration of high mass contaminants that are present in the water and contaminants are also absorbed into the foods that we consume.^10-11 These contaminants include both regulated and unregulated chemicals.

According to the New Orleans Sewage and Water Board’s 2024 Annual Report on Water Quality, reported averages for regulated contaminants like Atrazine and Simazine did not exceed federal quality standards established by the EPA. However, for heavy metals such as lead and copper, current data is not available and values were reported from the latest survey in 2022. In addition, the values for unregulated chemicals like PFOS, HFPO-DA, and PFOA were reported relative to an arbitrary value and not a federally mandated limit of exposure. Bacterial contaminants were also reported. Coliform bacteria was detected at safe levels, but measurements for other biological contaminants like E.coli and other harmful bacteria linked to waterborne illnesses were not determined. The absence of such measurements creates a knowledge gap between the actual and reported composition of tap water in the City of New Orleans and highlights the need for multiple assessments and parallel studies to increase the public’s confidence in published water quality reports.

In New Orleans, the locals are accustomed to boil water advisories in the event of flooding. Since the city sits below sea level, flood waters that contain harmful pathogens and chemicals linger. Contaminants like E.coli infiltrate treated water reserves when flood waters breach sewage treatment plants.^12-16 Rising concerns that global warming will increase the occurrence of storms that cause catastrophic flooding are shared among the residents of New Orleans and with residents in neighboring gulf states. At an average elevation of approximately 8 feet below sea level,¹⁷ the City of New Orleans is a uniquely qualified destination to investigate correlations between the occurrence of flooding and tap water quality in urban cities.

3. Methods

Participants/Sample

Location Selection - The LSU Ag Center publishes flood maps in partnership with FEMA to map flood zones A-X for insurance quoting purposes. The map legends will be used to randomly select 3 locations from each zone in which the potential for flooding is either absent, moderate, or high. We will make note of the proximity of each location to industrial operations

Sample Collection – Sampling will occur in triplicate in publicly available locations that fall between 0-14 feet below sea level. Samples will be collected from locations with and without levee protection. HDPE bottles will be used to collect water samples (after a 30 second flush) at the same time each day (12pm). Appropriately labeled samples will be stored on ice pending transport, stored at 4°C, and analyzed within 48 hours.

Materials and Procedures

Samples will be characterized via the following analytical methods.

Planned Analyses

- Shimitzu TOC Analyzer: Total organic carbon analysis to quantify the organic contaminants present relative to nano pure water.

- Shimitzu TON Analyzer: Total organic nitrogen to identify any nitrogen containing contaminants.

- Horiba Aqualog analysis - Characterize changes in excitation and emission maxima that would indicate contamination.

- ICP-MS - Quantitative analysis of heavy metals

- GC-MS - (optional) Quantify volatile organic compounds using head space analysis.

- SDS-PAGE/Western Blotting – (optional) if nitrogen contaminants are found we will perform non-targeted analysis to identify common biological contaminants.

- Specific Conductivity/pH – Characterize physiological characteristics of the tap water samples.

Ethics and Data Management

Data shall be compared to annual reports, and any trends or findings used to generate publications, posters, and presentations will be publicly available. The author is unaffiliated and there are no ethical concerns to disclose.

4. Budget (Pilot)

Anticipated Expense	Purpose	Anticipated Cost
PI Stipend (11 months x $2000)	Project management, manuscript authorship, experimental design,	$22,000
1 Intern/lab staff (11 months x $1000)	Support lab hygiene and sample prep	$11,000
Gas Cylinders (Zero Air, Argon, Helium)	TOC, TON, GC-MS, ICP-MS Analysis	$300
Gas Cylinder Storage Fees	TOC, TON, GC-MS, ICP-MS Analysis	$300
Lab Supplies (solvents, HDPE bottles, Kem wipes, PPE, GC column, glass amber vials with and without septa, centrifuge tubes, GF filters ect.)	Project execution	$5000
Journal Publishing Fees	Share scientific findings	$3000
Total:		Total: $41,600

5. Project Timeline 2025-2026

October 2025	Method development and planning
November 2025	Site Selection
December 2025	Sample collection and Analysis
January 2026	Sample collection and Analysis
February 2026	Sample collection and Analysis
March 2026	Data Analysis and Manuscript Preparation
April 2026	Data Analysis and Manuscript Preparation
May 2026	Data Analysis and Manuscript Preparation
June 2026	Data Analysis and Manuscript Preparation
July 2026	Manuscript Review
August 2026	Manuscript Submission
September 2026	Final Manuscripts Edits

6. References

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6. MacKeown H, Magi E, Di Carro M, Benedetti B. Removal of perfluoroalkyl and polyfluoroalkyl substances from tap water by means of point-of-use treatment: A review. Sci Total Environ. 2024 Dec 1;954:176764. doi: 10.1016/j.scitotenv.2024.176764. Epub 2024 Oct 10. PMID: 39393709.

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8. Pardue JH, Moe WM, McInnis D, Thibodeaux LJ, Valsaraj KT, Maciasz E, van Heerden I, Korevec N, Yuan QZ. Chemical and microbiological parameters in New Orleans floodwater following Hurricane Katrina. Environ Sci Technol. 2005 Nov 15;39(22):8591-9. doi: 10.1021/es0518631. PMID: 16323752.

9. Schwab KJ, Gibson KE, Williams DL, Kulbicki KM, Lo CP, Mihalic JN, Breysse PN, Curriero FC, Geyh AS. Microbial and chemical assessment of regions within New Orleans, LA impacted by Hurricane Katrina. Environ Sci Technol. 2007 Apr 1;41(7):2401-6. doi: 10.1021/es062916x. PMID: 17438793.

10. Liu S, Liu J. An Integrated Approach of Bioassays and Non-Target Screening for the Assessment of Endocrine-Disrupting Activities in Tap Water and Identification of Novel Endocrine-Disrupting Chemicals. Toxics. 2024 Mar 28;12(4):247. doi: 10.3390/toxics12040247. PMID: 38668470; PMCID: PMC11054029.

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16. Woznicki SA, Barber J, Butcher JB, Essoka J, Harris M, Mehaffey M, Pluta B, Shabani A, Whung PY. Compound Impacts of Fluvial Flooding and Sea-Level Rise on Benzo[a]pyrene Transport in the Lower Darby Creek Area Superfund Site, Pennsylvania, USA. ACS ES T Water. 2025 Jun 20;5(7):3613-3627. doi: 10.1021/acsestwater.4c00814. PMID: 40673109; PMCID: PMC12261278.

17. Campanella, Richard. 2018. “New Orleans Was Once Above Sea Level.” Open Rivers: Rethinking Water, Place & Community, no. 11. https://openrivers.lib.umn.edu/article/new-orleans-was-once-above-sea-level/. DOI: https://doi.org/10.24926/2471190X.4718

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Investigating the occurrence of contaminants in tap water relative to flood zone status in the “Big Easy”

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