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The Mississippi River System is of great ecological and economic importance, making it crucial to monitor contaminants within it. While nutrient pollution is well studied, there are little data on microplastics (MPs) in the Mississippi River System (MSRS), especially during drought conditions. Herein, we characterize MP pollution from seven sites across the MSRS during both flash drought and non-drought periods using FTIR microspectroscopy (µ-FTIR). Additionally, we evaluate the impact of multiple water level conditions on MP polymer composition across five time points at a single sampling site. Of all MPs identified, polyethylene terephthalate (PET, 22%), resin (17%), and polyethylene (PE, 10%) were the most abundant polymers. Average concentrations ranged from 16 to 381 MPs/L across seven sites, with no significant difference in concentration between conditions. Irregular particles were the most common morphology, with most MPs falling in the lowest size range measured (30–100 μm). Drought condition had a significant (p < 0.001) impact on polymer composition, and polymers most strongly correlated with flash drought were mostly fluoropolymers. For the single sampling site, concentrations differed, but not significantly, across the five timepoints. These results demonstrate the complex relationship between MP concentration and drought condition, and also highlight the importance of fully characterizing MPs in environmental studies.
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Hydrometeorological Drivers of the 2023 Louisiana Water Crisis
Abstract During summer and fall 2023, Louisiana experienced a historic local drought while dry conditions elsewhere in the central US withheld vital runoff from the Mississippi River, leading to below‐normal discharge into the Gulf of Mexico. Thus, by late October 2023, Louisiana was gripped by two super‐imposed water crises: a severe local drought and saltwater contamination in the Mississippi River channel. This study frames the development of the water emergency through the lens of flash drought using the Evaporative Demand Drought Index (EDDI). The EDDI shows south Louisiana experience a flash drought during June 2023, while the Mississippi River basin was subsequently characterized by large expanses of high‐percentile EDDI in August‐September 2023 shortly before the saltwater intrusion episode along the lower Mississippi River. Over the last 15 years, MRB‐wide EDDI percentile has oscillated between years‐long elevated and depressed states, accounting for 23.7% of the monthly discharge anomaly near New Orleans.
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- PAR ID:
- 10508292
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 51
- Issue:
- 10
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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