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Ecological Intelligence / Subject

microplastics

Peer-reviewed Latin America & Caribbean

Amazon floodplain microplastics appeared at both fishing and settlement sites

Evidence
Peer-reviewed
Geography
Lake Canaçari, Central Amazon, Brazil; dry-season sampling
System
Floodplain lake; microplastic monitoring; freshwater sediments

WHAT THE EVIDENCE SAYS

Dry-season sampling detected microplastics across surveyed areas of Amazonian Lake Canaçari. Water concentrations ranged from no particles in one sample to 1,000 particles per cubic meter, averaging about 405; sediments ranged from 7 to 307 particles per kilogram, averaging about 77. Blue fibers dominated, and fishing-versus-settlement sampling groups did not differ significantly in measured particle concentrations.

WHY IT MATTERS / OUR READ

A mapped local human-use category can be a poor proxy for where mobile contaminants accumulate in connected floodplain waters. Repeated seasonal and hydrologic monitoring is needed before a management team attributes material to a specific shore use.

CAVEATS / UNCERTAINTY

These are field detections during one hydrologic season, not proof of source, toxic dose or ecosystem damage. No significant between-group difference is not evidence that all locations or all seasons are equivalent.

SOURCE

Guimarães et al. · Environmental Monitoring and Assessment · Amazon lake microplastics
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A newly published lake survey found pervasive particles but no significant contrast between its land-use groupings.

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Global

Field-scale microplastic effects on cropland function were weaker and less consistent than laboratory narratives suggest

Evidence
Peer-reviewed multi-site field experiment and global field synthesis
Geography
Four semi-arid cropland sites plus global field studies
System
Cropland / agricultural soils

WHAT THE EVIDENCE SAYS

A five-year experiment across four semi-arid cropland sites tested a high microplastic loading of 0.2% by weight, then paired those results with a synthesis restricted to outdoor field studies. Across crops, sites and years, the authors found no consistent negative functional response in yield, soil quality or multifunctionality. Average field-study effects were weak and heterogeneous, plant presence dampened some responses, and biodegradable polymers showed no consistent ecological advantage.

WHY IT MATTERS / OUR READ

The counter-signal is not that microplastics are harmless. It is that laboratory hazard signals do not map cleanly onto field-scale ecosystem function, so ecological risk assessment needs exposure context, vegetation and realistic field conditions.

CAVEATS / UNCERTAINTY

The study explicitly does not address microplastic uptake into crops, dietary exposure or toxicological risk. Weak average functional effects can coexist with other harms, and the experimental loading and semi-arid sites do not represent every soil, polymer or farming system.

SOURCE

Global Change Biology — primary study
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Five years across four semi-arid sites plus a field-only synthesis found no consistent overall loss of crop yield, soil quality or ecosystem multifunctionality—even at high experimental loading.

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Peer-reviewed North America

Hurricane Helene turned a background microplastic flux into an event-scale pulse

Evidence
Peer-reviewed
Geography
Western North Carolina, USA
System
Mountain headwaters / atmospheric deposition

WHAT THE EVIDENCE SAYS

Sampling at three western North Carolina sites before, during and after Hurricane Helene found storm-period microplastic deposition roughly 3–22 times pre-storm levels. The storm accounted for about 4.2%, 4.6% and 18.8% of annual deposition at the three sites, and the authors extrapolated an anomalous regional deposition pulse of roughly 3.85×10^15 particles across the affected area.

WHY IT MATTERS / OUR READ

Extreme events can compress a substantial share of an annual pollutant flux into a short window. Monitoring programs built around routine intervals may therefore miss the timing and magnitude of transport processes that matter most after major storms.

CAVEATS / UNCERTAINTY

This was a three-site observational event study. The regional particle estimate is modeled from site measurements, ecological and human-health effects were not measured, and atmospheric trajectory analysis does not fully resolve the sources of the deposited particles.

SOURCE

Integrated Environmental Assessment and Management
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At three western North Carolina monitoring sites, storm-period deposition rose 3–22× above pre-Helene levels; at one site, the storm supplied 18.8% of the year’s measured microplastics.

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