Agricultural mulch film is a bigger source than most people expect — and it doesn't stay on the farm.
Plastic film mulch — thin sheeting laid over cropland to suppress weeds and retain soil moisture — is one of the largest single sources of agricultural plastic pollution, and both macroplastic (>5 mm) and microplastic fragments accumulate directly in the soil it's applied to [1]. Field surveys have found that macroplastic and microplastic contamination levels on a given plot are positively correlated: more visible plastic debris on a farm predicts more microplastic fragmentation happening in that same soil.
That soil contamination doesn't stay put. Runoff, wind erosion, and irrigation discharge all move fragmented plastic off farmland and into waterways, which is one reason the MPFREE Standard's supply-chain scope matrix (see the agriculture-and-supply-chain articles) audits irrigation filtration and prohibits polyethylene mulch films specifically, rather than treating agricultural sourcing as out of scope for a product-focused certification.
Globally, plastic waste production has grown from roughly 180 million to nearly 400 million tonnes a year over two decades, and packaging alone accounts for the largest single share of that total, with only about 9% of all plastic waste ultimately recycled [2]. Agricultural plastic is a smaller slice of that total volume than packaging, but it has a distinguishing feature packaging waste doesn't: it's applied directly to the soil that grows food, which is what makes farm-level sourcing decisions a first-pillar concern for this Standard, not just a downstream-waste one.