Exploring the dynamic interplay between coastal ecosystems and anthropogenic influences through cutting-edge environmental analysis.
I am currently leading a comprehensive research project investigating seasonal and spatial variations in water and sediment quality in the Nueces/Corpus Christi Bay area, Texas. This ecologically significant coastal region faces increasing pressures from urban development, industrial activity, and climate change.
Research Objectives
- ✓ To analyze water samples to evaluate nutrient concentrations, and their seasonal and spatial variability, providing insights into water quality around the Nueces/Corpus Christi Bay system.
- ✓ To analyze the physical and chemical properties of sediment samples, including grain size, organic carbon, and nutrient concentrations, around the Nueces/Corpus Christi Bay system.
- ✓ To detect and quantify the presence of heavy metals and pesticides in water and sediment samples, understand their spatial and seasonal variability.
- ✓ To estimate the extent of pollutant loadings, including nutrients, sediments, heavy metals, and pesticides, around the Nueces/Corpus Christi Bay system.
Study Area
Study area map showing sampling locations around the Nueces/Corpus Christi Bay
Methodology
Methodology
Study Area
The research focuses on five representative sites in the Nueces/Corpus Christi Bay system:
Labonte Park (freshwater inflow), Nueces Bay (industrial/port area),
Bock Park (tidal exchange zone), Sugar Tree Apartments (urban/WWTP effluent),
and Ennis Joslin Road (urban–estuarine interface). These locations capture gradients of
hydrological, anthropogenic, and ecological influence on water and sediment quality.
Sample Collection
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Water samples: ~15 cm below surface using acid-washed HDPE bottles mounted on an
extendable pole. Bottles pre-cleaned per EPA guidelines (10% HNO3 soak, DIW rinse) to avoid trace
metal contamination (USEPA, 2002). Transferred to amber glass jars with Teflon®-lined caps, stored at ~4 °C on
ice, analyzed within recommended holding times (Wilde et al., 2004).
-
Sediment samples: Collected with a stainless-steel scoop, air-dried, and stored in pre-cleaned
amber jars. Tools and jars decontaminated before each use (Shelton & Capel, 1994).
Water Quality Analysis
-
Field parameters (pH, Temp, DO, TDS, Salinity, Conductivity):
in situ with YSI ProDSS; calibrated before each survey (USGS, 2008).
-
Nutrients:
- Ammonium: spectrophotometric (Nessler’s method) at 425 nm (Bartošová et al., 2013).
- Nitrate, nitrite, phosphate: Ion Chromatography (Dionex ICS-5000), EPA Method 300.0 (USEPA, 2007).
-
Suspended Sediment Concentration (SSC):
vacuum filtration through 0.40 µm filters, dried at 105 °C, gravimetric (APHA, 2017).
-
Heavy metals (water & suspended solids):
acidify with HNO3 (<pH 2), digest (EPA 3052), quantify by ICP-MS (USEPA, 1994).
-
Flow/discharge: Acoustic Doppler Current Profiler (ADCP, 2000 kHz StreamPro), velocity–area
discharge (Teledyne RD Instruments, 2017).
Sediment Analysis
- Grain size distribution: mechanical sieving & hydrometer; ASTM D422 (ASTM, 2007).
- Organic carbon: Loss-on-Ignition (LOI) at 550 °C for 4 h; ASTM D2974 (ASTM, 2014).
-
Nutrients in sediment:
- Total phosphorus: molybdenum blue colorimetry, 880 nm (USEPA, 1993; de Morais et al., 2021).
- Extractable nitrate/phosphate: 2 N KCl extraction + ion chromatography (USEPA, 1993).
-
Heavy metals: microwave digestion (Anton Paar Multiwave GO; HNO3/HCl/H2O2)
followed by ICP-MS (EPA 3052; USEPA, 1996).
-
Pesticides: Solid Phase Microextraction (SPME) + Gas Chromatography (Shimadzu GC-2014AFSC) with
thermal desorption (Flores et al., 2009; Camarena et al., 2016).
Data Analysis
- Descriptive statistics: temporal & spatial variability in Excel and Python (Parmar & Bhardwaj, 2014).
- Trend analysis: Mann–Kendall test for monotonic seasonal/long-term trends (Hirsch et al., 1982).
- Comparisons: Two-way ANOVA for seasonal (wet vs. dry) and spatial (site-to-site) effects (Darji & Lodha, 2025).
-
Correlations: Pearson’s correlation among water–sediment parameters (pH, DO, nutrients, metals,
organic C, particle size) to identify pollution drivers (Mohammed et al., 2022).
1
Labonte Park
Urban-adjacent freshwater site
2
Nueces Bay
Primary estuarine environment
3
Sgt. J.D. Bock Park
Recreational waterfront area
4
Sugar Tree Apartments
Residential runoff point
5
Ennis Joslin Road
Transportation corridor impact zone
Key Findings
Preliminary results reveal significant seasonal patterns:
Water Chemistry
- pH and salinity levels peak during fall
- Dynamic nutrient cycling patterns
Sediment Analysis
- Particle size shifts seasonally
- Organic carbon composition changes
Contaminant Trends
- Elevated nitrate concentrations
- Undetectable phosphate in November
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