• Examining the Presence of Microplastic in Wastewater-Derived Soil Amendment

      Koritkowski, Carlee; Garneau, Danielle (2020-05-05)
      There is growing research on the impact of microplastics in terms of uptake in consumer products (e.g., sea salt, bottled/tap water, beer, mussels, fish, and soil amendments). Studies have shown that wastewater effluent and biosolids are potential pathways for microplastics to enter marine, freshwater, and terrestrial environments. Some soil amendments derive from the bacterial mats associated with wastewater processing and are potential pathways of microplastics via soil runoff into surrounding waterbodies. The presence of microplastics in these ecosystems impacts food webs at varying trophic levels and contributes to the persistence of microplastics in the environment. We examined a wastewater-derived soil amendment for microplastics using standard characterization methods. Quantification of microplastics following distilled water hydration of 82g of soil amendment yielded 69 particles. These particulate were primarily fibers (69%) and foams (19%), with lesser films (4%), beads (4%), and fragments (3%). The majority were smaller (125-355um) fiber particles. A standard bag of this soil amendment is 14515g with coverage of 232m2. The average-sized lawn in the United States is approximately 911m2, resulting in the potential to contribute 330,240 particles into soil and ultimately adjacent waterways. Next steps have begun to streamline this process by adopting the wet peroxide oxidation digestion method in an attempt to reduce organic matter. Nile red staining is a recently introduced method that effectively binds to plastic and is visualized using ultraviolet light. Microplastic researchers have developed automated (MP-VAT) software to streamline microplastic quantification and characterization in conjunction with Nile red staining procedures. We aim to incorporate this new approach and evaluate best practices in microplastic quantification and characterization of wastewater-derived soil amendments, as their potential ecosystem consequences are broad. It is important to continue elucidating pathways of these emerging persistent pollutants.
    • Impacts on the growth of Sweet Corn (Zea Mays) exposed to plastic weed fabric and soil amendment with and without earthworms

      Lee, Linh; Gomez, Isabel; Garneau, Danielle (2020-05-05)
      Agricultural practices, such as farm field application of sewer sludge or use of plastic weed fabrics may impact yield of crop plants. Numerous studies have documented the presence of microplastics in wastewater treatment plant effluent and sludge and have noted negative impacts on terrestrial and aquatic organisms. Plastic mulch and weed fabrics are increasingly more common in small-scale farming and over time will degrade into finer microplastic particulate. Both plastic sources have the potential to leach residues into soils and adjacent waterbodies, with potential impacts on both plants and wildlife. Earthworm bioturbation has the potential to redistribute microplastics even deeper into the soils as they consume and lay castings. We established a greenhouse experiment to examine the effects of farming-associated plastics on Sweet Corn (Zea mays) in the presence of Red Worms (Eisenia foetida). We sowed 4 corn seeds per pot across 5 treatments (control, macroplastic, microplastic, amendment 1mm, amendment 355um) with 6 replicates per treatment and lined and covered the pots with screening. Once plants were established (13 days), two Red Worms were introduced to three pots across all treatments. Plant height was measured weekly and upon harvest, stem diameter, leaf abundance, and weights were obtained. Preliminary results suggest that the amendment hastened the date of first germination (6 days post-planting). All plants germinated in 1mm amendment and macroplastic, whereas minimum (88%) germination was observed in 355um amendment and microplastic treatments. There was a statistical difference in the height of Sweet Corn after a week with the tallest plants deriving from the 1mm amendment treatment (p = 0.037, F = 2.643, df = 119). This study serves to help elucidate the complex interactions of microplastic and soil-dwelling organisms on yield of crop plants. Our results will inform farmers and land managers about avoiding techniques that will potentially increase plastics inputs into ecosystems.
    • Microplastic Biomagnification in Invertebrates, Fish, and Cormorants in Lake Champlain

      Garneau, Danielle; Putnam, Alexandra; Clune, Alexis; Buksa, Brandon; Hammer, Chad; VanBrockin, Hope (2017)
      Microplastics are plastic particles that are microplastics, which are pellets commonly found in personal care products, and secondary microplastics, which are degraded plastics. Microplastics have made their way into waterbodies by passing through wastewater treatment plants, as marine debris, via mechanical- and photo-degradation of plastic, and release of pre-production raw materials. Microplastics are known to absorb other pollutants and are hydrophobic particles that can biomagnify up the food web. When ingested by fish, particulates embed within the digestive tract and leach into tissues, posing a potential concern for human consumption. The goal of this research was to determine whether microplastics biomagnify within invertebrates, fish, andPhalacrocorax auritus (Double-crested Cormorant) resident to Lake Champlain. We did so by quantifying and characterizing (e.g., fragment, fiber, film, foam, pellet) particulates. We performed wet peroxide oxidation digests on digestive tracts of (n = 438) lake organisms, specifically invertebrates (n = 258), 14 species of fish (n = 165), and Double-crested Cormorants (n = 15). Our research indicated that fibers were the most-abundant particulates in all organisms (n = 764), followed by fragments (n = 123), films (n = 40), pellets (n = 13), foam (n = 9). Microplastics were separated using stacked mesh sieves, with preliminary results showing a particulate size-distribution of: 1 mm, n = 86; less than 1 mm but 355 µm, n = 144; and less than 355 µm but 125 µm, n = 232. These findings illustrate biomagnification in Lake Champlain organisms, as invertebrates, fish, and Double-crested Cormorants contained on average 0.05, 3.6, and 22.93 microplastic particles. Results from this research serve to inform residents of the Lake Champlain watershed, anglers, non-profit lake organizations, as well as public health and government officials of the risks microplastics pose to aquatic biota and ultimately humans.
    • Microplastic Pollution: A Survey of Wastewater Effluent in Plattsburgh, NY

      Garneau, Danielle; Buksa, Brandon; Niekrewicz, Thomas (2016)
      Microplastic pollution in freshwater ecosystems is an emerging topic in aquatic pollution science. Primary microplastics were designed to be small (e.g., microbeads, pre-production plastic nurdles) and secondary microplastics result from photo and mechanical degradation. Origin of microplastics are often associated with consumer use of personal care items (e.g., facial cleansers and toothpastes) which are too small to be captured with current wastewater treatment plant (WWTP) technologies. Ongoing research cites dangers resulting in their propensity to absorb harmful chemicals and bioaccumulate up the food chain. We surveyed WWTP post-treatment effluent (N = 11) from the city of Plattsburgh, NY wastewater treatment plant in fall 2015. Effluent samples were collected and digested using wet peroxide oxidation methods, followed by characterization based on type and size. The majority of microplastics in wastewater effluent were identified as fibers (51%), as compared to similar proportions of pellets/beads (12%), films (15%), fragment (18%), and lesser films (4%). The largest (>=1mm) and smallest (<=125µm) were predominantly fibers (87%) and (44%), respectively. Diversity of microplastic type (e.g., film, fragment, foam) increased with decreasing particle size. On high and low flow rate days, more bead/pellet and films were collected respectively. Microplastics have been an emerging concern in aquatic life as they can absorb harmful chemicals and bioaccumulate up the food chain. This research from Lake Champlain can serve as a basis for further microplastic studies in the Lake Champlain watershed.
    • Spatial and Temporal Distribution and Abundance Microplastics in Lake Champlain Long-Term Monitoring Samples

      Garneau, Danielle; Allen, Eileen; Hagar, Susan-Marie; Austin, Lindsey (2017)
      Microplastics are particles less than 5mm in size, characterized as fibers, fragments, beads, foams, and pellets. Microplastics (MP) arise from four main processes: environmental degradation (UV exposure, mechanical and/or biological), direct release by means of wastewater treatment processing, unintentional loss of raw materials, and discharge of macerated wastes. Microplastics are potentially toxic to aquatic biota and the presence of microplastics in freshwater ecosystems is largely under-researched. The goal of our research was to examine the spatial and temporal distribution of microplastics and pre-production particulate (nurdles) from long-term monitoring (LTM) zooplankton samples within Lake Champlain collected between 1992-2016. Nurdles were counted in full from samples, whereas microplastics (e.g., fragments, fibers) were subsampled due to size. Fourier Transform Infrared Spectroscopy (FTIR) characterized nurdles as polyisoprene rubber ribbon. Within the LTM samples (n = 2265), nurdles (n = 3455) and microplastics (n = 249), predominantly fibers, were identified. The greatest microplastic abundance was noted in 2015 (n = 73 microplastics, n = 494 samples). Nurdles were found only in samples that had been collected 2012-2016, with the greatest nurdle abundance noted in 2012 (n = 1,169 nurdles, n = 412 samples) and at varying depths. Nurdle abundance declined since the 2012 peak and in 2015 was greatly reduced (n = 531 nurdles, n = 494 samples). Spatial distribution maps suggest the complexity of the story with high abundances at deep central locations, as well as shallow isolated bays. The high influx of nurdles in 2012 may be related to the 2011 Lake Champlain flood; however more research will need to be conducted to tease apart timing and potential nurdle point-sources (e.g., train tracks, industrial/urban centers).