We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Uptake, Distribution, and Impact of Micro- and Nano-Plastics in Horticultural Systems Using Lettuce (Lactuca sativa) as a Model Crop
Summary
Researchers studied how micro- and nanoplastics are taken up and distributed in lettuce grown in horticultural systems, finding that nanopolystyrene exposures significantly inhibited leaf and root development in a concentration-dependent manner. They optimized extraction methods for quantifying microplastics in soil and developed a synthesis procedure for nanoplastic test particles. The study demonstrates that plastic fragments from horticultural materials can accumulate in soil and affect crop growth, raising concerns about food safety.
Plastics are integral to horticulture, with millions of tonnes used annually for crop protection and packaging. Despite enhancing productivity, plastic fragmentation, contamination, and accumulation pose underexplored environmental and crop cultivation concerns. This thesis enhances the knowledge of micro- and nanoplastics fate in soil, plants, and horticultural systems, emphasising environmentally representative approaches. Soils are sinks for horticultural plastics, necessitating reliable quantification to contextualise risks to plant health and production. Accordingly, an extraction, fluorescent staining, and FTIR characterisation procedure was optimised using organic content extremes and representative microplastic polymers, densities, dimensions, and degradation phases, yielding high matrix removals and plastic recoveries >96 %. Recognising further fragmentation, polystyrene nanoplastics (~30 nm, spherical, uniform, negatively charged, minimally aggregating) were synthesised and characterised, providing insights into their impact and uptake potential during hydroponic lettuce (Lactuca sativa) exposures. Across 0.01-1000 mg/L nanopolystyrene exposures, leaf and root development inhibition was significantly concentration dependent (9.3-96.4 %). Conversely, chlorophyll and elemental concentrations remained adequate for growth. Synthesis impurity controls attributed toxicity primarily to nanopolystyrene, potentially through root blockage, growth reallocation, or uptake-related damage. Carbon-14-radiolabelling enabled highly sensitive nanopolystyrene quantification and localisation in lettuce at an environmentally relevant concentration, 0.3 µg/L [14C]nPS, facilitated by liquid scintillation counting and autoradiography. Strong root association (6.68 ± 1.40 ng/g), limited leaf uptake (0.08 ± 0.005 ng/g; 4.36 % translocation), and greater accumulation in older leaves suggest entrapment or protective sequestration, demonstrating nanoplastic pathways into edible tissue. A Life Cycle Assessment contextualised laboratory-derived data, linking realistic plastic contamination scenarios (0.06-1.74 %) to reduced lettuce growth, demonstrating that increased land or inputs to maintain marketable yields could elevate global warming potential, terrestrial and freshwater ecotoxicity, and fossil resource consumption by up to 39 %. Collectively, these novel findings evidence nanoplastic impact, detection, and localisation in lettuce, highlighting significant, emerging horticultural concerns under environmentally relevant conditions.
Sign in to start a discussion.
More Papers Like This
Internalization, physiological responses and molecular mechanisms of lettuce to polystyrene microplastics of different sizes: Validation of simulated soilless culture
This study found that lettuce plants absorb polystyrene microplastics through their roots and transport them to their leaves, with smaller particles (100 nanometers) moving more easily than larger ones. Both sizes reduced plant growth by roughly 38-48% and triggered stress responses including changes in gene expression. These findings raise food safety concerns since microplastics in soil can accumulate in leafy vegetables that people eat.
Potential impact and mechanism of aged polyethylene microplastics on nitrogen assimilation of Lactuca sativa L.
Researchers investigated how aged polyethylene microplastics of different sizes affect nitrogen uptake and metabolism in romaine lettuce. They found that aged microplastics, especially smaller particles, accumulated in the plants and disrupted nitrogen assimilation processes. The study suggests that microplastic contamination in agricultural soils may affect crop nutrition and quality by interfering with how plants absorb and process essential nutrients.
Uptake and accumulation of microplastics in an edible plant
Researchers demonstrated for the first time that edible plants can take up and accumulate microplastics from soil. Using fluorescently labeled polystyrene beads, they showed that 0.2-micrometer particles entered lettuce roots through small cracks at lateral root emergence sites, traveled through the vascular system, and accumulated in the leaves. The findings raise concerns about a previously unrecognized pathway for human microplastic exposure through the consumption of vegetables grown in contaminated soil.
Effect of microplastics on dry matter content in Lactuca sativa L.
This study tested the effects of microplastic particles on dry matter content in lettuce plants, finding that microplastic exposure affected plant biomass production. As agricultural soils accumulate microplastics, their effects on crop yield and nutritional quality become important food safety concerns.
Soil moisture and texture mediating the micro(nano)plastics absorption and growth of lettuce in natural soil conditions
Experiments growing lettuce in natural agricultural soil showed that microplastics and nanoplastics are taken up and transported through roots, stems, and even leaves, and that higher soil moisture accelerates this uptake and migration. Because the study used realistic soil conditions, it strengthens concerns that food crops may be accumulating plastic particles that consumers then ingest.