Steve Ring and Bob Suchanek
Water and Wetlands Stewards
Walking the Field. Photo Credit - Bob Suchanek
Researchers say that more microplastics pollution is getting into farm soil than oceans—and these tiny bits are showing up in our fruits, veggies, and bodies. - Kate S Petersen, Environmental Health News
The Water & Wetland Stewards of the Minnesota Sierra Club, research, monitor, and advocate for policies that protect Minnesota’s waters and wetlands. They have a small team that has been tracking legislation related to microplastics and stopping their spread.
In the 2021- 2022 Minnesota Legislative session, we were pleased to see a bill representing a crucial first measure introduced by Representatives Rick Hansen, District 52A and Sydney Jordan, District 60A. The bill, HF 3751, prohibited the sale of pesticide and fertilizer coated with plastic or other non-biodegradable materials. Although the bill failed to gain traction during this legislative session, the Sierra Club Water and Wetlands Stewards see it as crucial to further discussions about plastics and agriculture.
Microplastics are pieces of plastic smaller than 5.0 mm (about 0.2 inches). Around ¾ of all microplastics are accumulating on land. Some are secondary products of degradation, such as black plastic bits from mulching film used to prevent weed growth and retain moisture. Others, the “primary” microplastics, are intentionally manufactured. For example, plastic-coated microcapsules in pesticides and fertilizers allow for controlled chemical release over time. While the chemicals may eventually dissipate, the plastic will not.
Although research on microplastics is still ongoing, preliminary findings suggest:
- Plastics can alter the compositions of organisms in the soil. “Overall, our field-based microplastic additions resulted in reductions of abundance and shifts in the community composition of soil fauna, especially at the high level of microplastic concentration” (Dunmei, et. al., 2020).
- Microplastics can travel through the soil into aquifers (especially in karst regions such as those in the SE part of Minnesota), and interfere with soil invertebrates and microorganisms (Wanner, Philipp, 2021).
- Plastics may be a vector for other toxic materials. Chemicals, such as pesticides, may become attached to plastic particles and carried into surface and groundwaters. A Kansas State University researcher who grew wheat in different concentrations of plastic and cadmium (a toxic metal) found that “the plants grown with microplastics were more cadmium-contaminated. The plastics really were acting as the vector for uptake of the cadmium" (Peterson, Kate S., 2020).
- Plastics in the soil can threaten drinking water supplies. “Hence, the deposited plastic in agricultural soils likely poses a major risk for underlying aquifers and drinking water supplies that rely on groundwater resources below farmlands to be contaminated by plastic and pesticides” (Wanner, Philipp, 2021).
This research demonstrates that “improved regulatory measures are necessary regarding the general usage of plastic in the farming process to protect aquifers and drinking water supplies from plastic and pesticide contamination and to avoid a potential human health hazard” (Wanner, Phillip, 2021).
The Water & Wetland Stewards submitted testimony about the dangers of microplastics and in support of the bill to the House Ag & Finance Committee during the last session. While the bill did not advance in the 2022 session, it provided an opportunity to educate legislators on the issue. We are looking forward to continuing to advance the bill in the coming legislative session.
If you’re interested in learning more or supporting our efforts - join the Water & Wetland Stewards at our monthly meeting, the next meeting will be Monday, Sept. 12 at 7 pm and/or reach out to Steve Ring at steve.ring@northstar.sierraclub.org
Sources
Lin Dunmei, Yang Guangrong, Dou Pengpeng, Qian Shenhua, Zhao Liang, Yang Yongchuan and Fanin Nicolas, 2020, “Microplastics negatively affect soil fauna but stimulate microbial activity: insights from a field-based microplastic addition experiment”, Proc. R. Soc. B.,287, 20201268,
http://doi.org/10.1098/rspb.2020.1268
Philipp Wanner, “Plastic in agricultural soils – A global risk for groundwater systems and drinking water supplies? – A review”, Chemosphere, Volume 264, Part 1, 2021, 128453, ISSN 0045 6535 (https://www.sciencedirect.com/science/article/pii/S0045653520326485)
Kate S. Peterson, “Microplastics in farm soils: A growing concern”, Environmental Health News, August, 2020, https://www.ehn.org/plastic-in-farm-soil-and-food-2647384684.html
https://www.panna.org/blog/yet-another-pesticide-issue-microplastics
https://www.ciel.org/wp-content/uploads/2022/05/Sowing-a-Plastic-Planet_final23may22.pdf