We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Low-density polyethylene microplastics as a source and carriers of agrochemicals to soil and earthworms
Summary
Researchers investigated whether low-density polyethylene microplastics could act as carriers of agrochemicals in soil and found that the particles both released their own chemical additives and transported pesticides to earthworms. The study suggests microplastics in agricultural soils may serve as a previously underappreciated pathway for chemical exposure in soil organisms.
Environmental context Microplastics, long recognised as contaminants in aquatic ecosystems, are increasingly of environmental concern for terrestrial ecosystems. This study focuses on the potential of microplastics to act as carriers of agrochemicals and the subsequent effects on soil biota. The results indicate the need for further studies into how soil properties influence both the degradation of microplastics and their role as pollutant carriers. Abstract Microplastics (MPs) are of environmental concern to marine ecosystems owing to the evidence of their presence in and adverse effects on organisms, but studies to address this problem on soils and its biota are scarce. Several questions can arise related to this major environmental problem and its impact on terrestrial ecosystems, mainly, whether MPs can transport contaminants (e.g. pesticides) to the soil matrix and if they can be a carrier of pesticides to soil biota. To contribute to the understanding of these issues, earthworms (Eisenia fetida) were exposed for 14 days to soil containing two different sized MPs (5 mm and 0.25 µm–1 mm) that were either previously sprayed or not with chlorpyrifos (CPF). Acetylcholinesterase (AChE) activity and thiobarbituric acid reactive substances (TBARS) were measured to track the exposure of the earthworms to MPs, both non-sprayed and sprayed with CPF. The behaviour of the earthworms in the test containers and the movement of MPs in the soil were assessed. The concentration of CPF in soil at the end of the experiment differed between the treatments with MPs of different sizes (17.9 ng g-1 and 2442 ng g-1 for large and small MPs, respectively). Despite the ability of the MPs to release CPF to the soil, the earthworms avoided the contaminated MPs at the highest contaminant level. At a lower concentration of CPF (large MPs), the earthworms avoided the MPs, but the contact time with contaminated soil was higher, as shown by the enhanced level of TBARs and AChE inhibition. However, no evidence of MPs uptake was recorded, thus it was not demonstrated that MPs can be carriers of pesticides to earthworms.
Sign in to start a discussion.
More Papers Like This
Influence on the processes of retention and transport of pesticides and ecotoxicity of microplastics in a tropical soil
Researchers investigated how high-density polyethylene microplastics from agricultural mulch films affect the behavior of three pesticides in tropical soil, finding that microplastics altered pesticide sorption, transport, and leaching while also increasing ecotoxicological effects on earthworms.
Biogenic transport of glyphosate in the presence of LDPE microplastics: A mesocosm experiment
A mesocosm experiment showed that earthworms can transport glyphosate and its breakdown product AMPA deeper into soil when low-density polyethylene microplastics are present, altering herbicide distribution compared to soil without microplastics. The results indicate that microplastics can indirectly affect pesticide fate in agricultural soils by modifying biological transport processes.
Assessing the role of polyethylene microplastics as a vector for organic pollutants in soil: Ecotoxicological and molecular approaches
Polyethylene microplastics were shown to act as vectors for organic pollutants including pharmaceuticals and pesticides in soil, with earthworm bioaccumulation assays and molecular endpoints revealing that MPs increased contaminant uptake compared to soil exposure alone.
Responses of earthworms exposed to low-density polyethylene microplastic fragments
Researchers exposed earthworms to low-density polyethylene microplastic fragments at various concentrations and studied the effects on their survival, growth, and reproduction. The microplastics affected earthworm behavior and caused measurable changes depending on concentration and exposure time. Since earthworms are critical for soil health and nutrient cycling, their sensitivity to microplastics raises concerns about how plastic pollution may degrade agricultural soils.
Polyethylene microplastics influence the transport of organic contaminants in soil
Laboratory experiments showed that polyethylene microplastics in soil altered the transport and distribution of organic contaminants, acting as secondary carriers that changed contaminant mobility through the soil matrix. The findings suggest microplastics in agricultural soils could inadvertently redistribute pesticides and other pollutants, with implications for groundwater quality.