Heavy Metals in Fish Samples Collected Between January 2021 and January 2022 from the Greater Houston Gulf Bay Region
Funded By:
National Academies of Sciences Gulf Research Program
Funding Cycle:
Healthy Ecosystems 4
Research Group:
Development of Gulf Coast Resiliency Management Plan Using Sentinel Species and Natural Infrastructure
Gioia Kennedy
Environmental Defense Fund
gkennedy@edf.org
tissue, biota, fish, heavy metal
Abstract:
As of February 2025, the entire Galveston Bay Estuary is under a fish advisory from the Texas Parks and Wildlife, primarily due to potential contamination from PCBs and dioxins. This research aimed to better understand potential public health implications for communities relying heavily on local fish for dietary needs by analyzing the presence and concentrations of heavy metals in fish samples from the area. To do this, we analyzed 64 fish samples collected between January 2021 and January 2022 for heavy metals from Trinity and Galveston Bay. This dataset captures the analysis of heavy metal concentrations in fish samples collected from the Houston Ship Channel and Trinity Bay, areas adjacent to multiple facilities reporting heavy metal emissions to the Toxic Release Inventory (TRI). The dataset is designed to address gaps in direct measurement of point source contamination and its potential health risks. The dataset includes trace metal concentrations in fish tissue to assess the potential human health risks associated with dietary exposure. Given the proximity of these water bodies to industrial activity, this study aims to evaluate the extent to which arsenic (As), mercury (Hg), cadmium (Cd), selenium (Se), lead (Pb), and copper (Cu) accumulate in fish species frequently consumed by local populations. Despite existing large-scale datasets on environmental contamination, direct measurements of metal concentrations in edible fish tissue are necessary to understand population-level exposure risks, particularly for chronic health conditions and cancer risk associated with arsenic ingestion. A total of 64 fish samples were obtained via local fishermen from Houston Ship Channel and Trinity Bay, comprising Black Drum (Pogonias cromis), Red Drum (Sciaenops ocellatus), and Speckled Trout (Cynoscion nebulosus). Fish were collected following Texas Parks and Wildlife Department (TPWD) size regulations, immediately stored on ice, and transported to B&B Laboratories in College Station, TX for tissue homogenization. Samples were then analyzed at the Trace Element Research Laboratory (TERL) at Texas A&M University using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) (EPA Method 200.8) to detect trace metal concentrations. Mercury levels were further analyzed using Cold Vapor Atomic Absorption (CVAA) and Cold Vapor Atomic Fluorescence (CVAF) per EPA Method 245. The dataset also includes quality control data, with method blanks, spike recoveries, and reference materials to ensure data accuracy. Sample collection was conducted over a defined period, ensuring seasonal variability was accounted for in Houston Ship Channel and Trinity Bay, Texas. These locations were selected due to their historical exposure to industrial pollutants and their role as key fishing areas for local consumption. The dataset reveals notable exceedances in arsenic (As) and selenium (Se) concentrations, with arsenic surpassing the Texas-specific screening level (TCEQ threshold of 0.036 mg/kg) and selenium exceeding safe dietary intake levels. Estimated Daily Intake (EDI) and Target Hazard Quotient (THQ) values indicate that arsenic and selenium pose potential health risks, particularly when considering chronic low-level exposure over time. This dataset serves as a critical resource for policymakers, researchers, and public health officials seeking to quantify real-world exposure risks from contaminated seafood and develop evidence-based risk mitigation strategies for populations consuming fish from industrially impacted water bodies.
Suggested Citation:
garett sansom. Heavy Metals in Fish Samples Collected Between January 2021 and January 2022 from the Greater Houston Gulf Bay Region. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/magdzgnd
Purpose:
The purpose of the analysis was to assess the presence and concentration of heavy metals in fish tissue samples. This evaluation focused on detecting trace amounts of key contaminants, including selenium, copper, mercury, cadmium, lead, and arsenic. The results provide important data on environmental exposure risks in the sampled areas.
Data Parameters and Units:
Arsenic (As*) (mg/kg) Cadmium (Cd) (mg/kg) Copper (Cu) (mg/kg) Mercury (Hg) (mg/kg) Lead (Pb) (mg/kg) Selenium (Se) (mg/kg) Estimated Daily Intake (EDI) (mg/kg bw/day) Estimated Weekly Intake (EWI) (mg/kg bw/week) Provisional Tolerable Weekly Intake (PTWI) (mg/kg bw/week) Target Hazard Quotient (THQ) (unitless) Reference Dose (RfD) (mg/kg bw/day) Mean Heavy Metal Concentration (mg/kg) TCEQ Screening Levels (mg/kg) Ratio of Mean Concentration to Screening Levels (unitless)
Methods:
Sample Collection Sixty-four fish samples were collected by hired local fishermen from the Houston Ship Channel and Trinity Bay, areas that are home to multiple facilities reporting heavy metal emissions to the Toxic Release Inventory. The collection included three species: Black Drum (Pogonias cromis), Red Drum (Sciaenops ocellatus), and Speckled Trout (Cynoscion nebulosus). All fish were collected in accordance with Texas Parks and Wildlife Department regulations, ensuring they met mandatory length requirements. After capture, the fish were immediately placed on ice to preserve their condition and transported to B&B Laboratories in College Station, TX. Tissue samples were prepared by homogenizing a portion of the fish tissue and weighing approximately 1 gram (wet weight) into a vessel. An ion pairing agent was added, and the samples were vortexed. Samples were then sent to the Trace Element Research Laboratory (TERL) at Texas A&M University for metal analysis. Trace Metal Determination Biota samples were analyzed for trace metals using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). This method measured trace concentrations of Selenium (Se), Copper (Cu), Mercury (Hg), Cadmium (Cd), Lead (Pb), and Arsenic (As) in the tissue samples. ICP-MS has become increasingly utilized due to its sensitivity, although interferences from molecular ions can sometimes cause overestimation depending on the sample matrix. Analyses were conducted using a Perkin Elmer/Sciex DRC-2 instrument equipped with multiple nebulizer types, spray chambers, and a dynamic reaction cell (DRC) to mitigate molecular ion interferences. Experience with tissue samples has informed the selection of appropriate isotopic ratios to identify and correct for spectral overlaps. The instrument is capable of detecting approximately 70 elements at very low concentrations (ppb to sub-ppb levels). Mercury was determined using cold vapor atomic absorption (CVAA) or, when greater sensitivity was required, cold vapor atomic fluorescence (CVAF). When necessary, hydride generation atomic fluorescence (HGAF) analysis was used for the determination of Arsenic and Selenium. Trace metal detection limits for tissue samples typically ranged from 10 to 500 ppb (dry weight). Quality assurance and quality control (QA/QC) procedures included the use of method blanks, blank spikes, quality control samples (QCS), matrix spike/matrix spike duplicates, and laboratory duplicates, with each batch consisting of no more than 19 samples. Standard reference materials (SRMs) were incorporated where applicable. All samples, including QC samples, underwent identical preparation and analysis procedures. Additionally, an appropriate surrogate solution was added to every sample to ensure consistent and accurate measurements. These measures were essential for verifying the reliability and accuracy of the analytical results.