More movement with manure: increased mobility of erythromycin through agricultural soil in the presence of manure.

Antibiotic residues in the environment threaten soil and aquatic organisms and human and livestock health through the building of antimicrobial resistance. Manure spreading associated with animal agriculture is one source of environmental antibiotic residues. To better understand the risk of contamination, we studied the adsorption of erythromycin, a model macrolide antibiotic used across human and animal medicine. We conducted a series of equilibrium batch experiments to determine the kinetics and extent of adsorption and a continuous-flow column adsorption experiment to observe non-equilibrium adsorption patterns. We determined that the adsorption equilibration time to soil was approximately 72 h in our batch experiments. Erythromycin adsorbed to soil relatively strongly (K = 8.01 × 10-2 L/mg; qmax = 1.53 × 10-3 mg/mg), adsorbed to the soil in the presence of manure with less affinity (K = 1.99 × 10-4 L/mg) at a soil: manure ratio of 10:1 by mass, and did not adsorb to manure across the solid ratios tested. We observed multi-phased adsorption of erythromycin to the soil during the non-equilibrium column experiment, which was largely absent from the treatments with both soil and manure present. These results suggest that erythromycin is more mobile in the environment when introduced with manure, which is likely the largest source of agriculturally sourced environmental antibiotics.

Oxic-anoxic cycling promotes coupling between complex carbon metabolism and denitrification in woodchip bioreactors.

Denitrifying woodchip bioreactors (WBRs) are increasingly used to manage the release of non-point source nitrogen (N) by stimulating microbial denitrification. Woodchips serve as a renewable organic carbon (C) source, yet the recalcitrance of organic C in lignocellulosic biomass causes many WBRs to be C-limited. Prior studies have observed that oxic-anoxic cycling increased the mobilization of organic C, increased nitrate (NO3 - ) removal rates, and attenuated production of nitrous oxide (N2 O). Here, we use multi-omics approaches and amplicon sequencing of fungal 5.8S-ITS2 and prokaryotic 16S rRNA genes to elucidate the microbial drivers for enhanced NO3 - removal and attenuated N2 O production under redox-dynamic conditions. Transient oxic periods stimulated the expression of fungal ligninolytic enzymes, increasing the bioavailability of woodchip-derived C and stimulating the expression of denitrification genes. Nitrous oxide reductase (nosZ) genes were primarily clade II, and the ratio of clade II/clade I nosZ transcripts during the oxic-anoxic transition was strongly correlated with the N2 O yield. Analysis of metagenome-assembled genomes revealed that many of the denitrifying microorganisms also have a genotypic ability to degrade complex polysaccharides like cellulose and hemicellulose, highlighting the adaptation of the WBR microbiome to the ecophysiological niche of the woodchip matrix.

Field assessment of metal and base cation accumulation in green stormwater infrastructure soils.

Green stormwater infrastructure (GSI) is adopted to reduce the impact of stormwater on urban flooding and water quality issues. This study assessed the performance of GSI, like bioretention basins, in accumulating metals. Twenty one GSI basins were considered for this study, which were located in New York and Pennsylvania, USA. Shallow (0-5 cm) soil samples were collected from each site at inlet, pool, and adjacent reference locations. The study analyzed 3 base cations (Ca, Mg, Na) and 6 metals (Cd, Cr, Cu, Ni, Pb, and Zn), some of which are toxic to ecosystem and human health. The accumulation of cations/metals at the inlet and pool differed between the selected basins. However, accumulation was consistently higher at the inlet or the pool of the basin as compared to the reference location. Contrary to prior research, this study did not find significant accumulation with age, suggesting that other factors such as site characteristics (e.g., loading rate) might be confounding. GSI basins that receive water only from parking lots or parking lots and building roofs combined showed higher metals and Na accumulation as compared to the basins that received stormwater only from building roofs. Cu, Mg and Zn accumulation showed a positive relationship with the organic matter content in soil, indicating likely sorption of metals on organic matter. Ca and Cu accumulation was greater in GSI basins with larger drainage areas. A negative relationship between Cu and Na implies that Na loading from de-icers may reduce Cu retention. Overall, the study found that the GSI basins are successfully accumulating metals and some base cations, with highest accumulation at the inlet. Additionally, this study provided evidence of GSI effectiveness in accumulating metals using a more cost efficient and time averaged approach compared to traditional means of stormwater inflow and outflow monitoring.

Reducing adverse impacts of Amazon hydropower expansion.

Proposed hydropower dams at more than 350 sites throughout the Amazon require strategic evaluation of trade-offs between the numerous ecosystem services provided by Earth's largest and most biodiverse river basin. These services are spatially variable, hence collective impacts of newly built dams depend strongly on their configuration. We use multiobjective optimization to identify portfolios of sites that simultaneously minimize impacts on river flow, river connectivity, sediment transport, fish diversity, and greenhouse gas emissions while achieving energy production goals. We find that uncoordinated, dam-by-dam hydropower expansion has resulted in forgone ecosystem service benefits. Minimizing further damage from hydropower development requires considering diverse environmental impacts across the entire basin, as well as cooperation among Amazonian nations. Our findings offer a transferable model for the evaluation of hydropower expansion in transboundary basins.

Roadside ditch macroplastic and other litter dataset in the Finger lakes region across land uses and COVID-19 pandemic.

Litter was collected from 12 roadside ditches in the Finger lakes Region of New York State over two sampling periods: pre-COVID-19 pandemic and during COVID-19 pandemic. Litter pieces were washed in DI water, oven dried, massed and plastic-type visually determined. Macroplastic data was analysed to assess the impact of land use, traffic, and COVID-19 variables on macroplastic accumulation on a piece, mass, and plastic-type basis. These data are all litter pieces collected, including both plastics categorized as 1 through 7 in the RIC resin classification codes as well as non-plastic litter. These data have wide-ranging reuse potential, as terrestrial microplastic accumulation is not well documented. These data could be compared with other litter accumulation across regions, specifically to assess total environmental macroplastic loading and enable contaminant mitigation strategies. These data also have direct application to modelling and transport of macroplastics into surface water bodies as a result of road ditch sampling locations. Macroplastic accumulation data across varying land uses, traffic, and COVID-19 conditions has been published [1].

What You Net Depends on if You Grab: A Meta-analysis of Sampling Method's Impact on Measured Aquatic Microplastic Concentration.

Microplastic pollution is measured with a variety of sampling methods. Field experiments indicate that commonly used sampling methods, including net, pump, and grab samples, do not always result in equivalent measured concentration. We investigate the comparability of these methods through a meta-analysis of 121 surface water microplastic studies. We find systematic relationships between measured concentration and sampled volume, method of collection, mesh size used for filtration, and waterbody sampled. Most significantly, a strong log-linear relationship exists between sample volume and measured concentration, with small-volume grab samples measuring up to 104 particles/L higher concentrations than larger volume net samples, even when sampled concurrently. Potential biasing factors explored included filtration size (±102 particles/L), net volume overestimation (±101 particles/L), fiber loss through net mesh (unknown magnitude), intersample variability (±101 particles/L), and contamination, the potential factor with an effect large enough (±103 particles/L) to explain the observed differences. On the basis of these results, we caution against comparing concentrations across multiple studies or combining multiple study results to identify regional patterns. Additionally, we emphasize the importance of contamination reduction and quantification strategies, namely that blank samples from all stages of field sampling be collected and reported as a matter of course for all studies.

Macroplastic accumulation in roadside ditches of New York State's Finger Lakes region (USA) across land uses and the COVID-19 pandemic.

Macroplastics are a ubiquitous and growing environmental contaminant with impacts in both marine and terrestrial systems. Marine sampling has dominated research in this field, despite the terrestrial origins of most plastic debris. Due to the high surface water connectivity facilitated by roadside ditches, these landscape features provide a unique sampling location linking terrestrial and surface water systems. We collected and analyzed macroplastic accumulation by number of pieces, mass, and polymer type in roadside ditches across four land uses, before and during the COVID-19 pandemic in the Finger Lakes Region of New York State. Commercial land use plastic accumulation rate was highest, while forested land use accumulation rates were lowest on a piece basis. Pre-COVID-19 piece accumulation rates were significantly higher than COVID-19 piece accumulation rates across all land uses. Mass accumulation rates followed similar patterns observed in piece accumulation, but the patterns were not always statistically significant. Plastic type 4 (i.e. thin plastic films), especially plastic bags and wrappers, was the most frequently collected type of macroplastic by piece across all land uses within the 1-7 Resin Identification Codes. By mass, the data were distributed less consistently across land uses. Cigarette filters, containing the polymer cellulose acetate, were the most frequently found roadside plastic, but are not within the 1-7 classification system. Our results suggest that policies in place limiting plastic bag usage could substantially reduce roadside plastics but other plastics, such as food wrappers and other single use plastic films, which comprised a large proportion of the plastic debris collected, should also be regulated to further decrease macroplastic pollution.

Dairy farmer perceptions of antibiotic transport and usage in animal agriculture dataset.

These data were from semi-structured interviews with dairy farmers. The content of the interviews focused on antibiotic transport and usage on dairy farms. Twenty-seven interviews were conducted in Central New York in 2019. Interviews were recorded and subsequently transcribed for qualitative thematic analysis. Qualitative coding analysis was preformed using ATLAS.ti and content filtered to ensure farmer anonymity. The dataset includes direct quotations from dairy farmers paired with farm and farmer characteristics. Quotations are subdivided thematically into the themes of disease prevention, antibiotic usage, non-antibiotic treatments, antibiotic transport, and environmental residue presence impacts, as structured in Georgakakos et al. [1]. Farm characteristics include management practice, farm size, and farm generation. Farm size was determined by number of lactating cows: small (0-50), medium-small (51-100), medium (101-500), medium-large (501-1000), and large (>1000). Farmer characteristics were farmer age categorized by birth year: Baby Boomer (1946-1964), Gen X (1965-1980), and Millennial (1981-1996). This dataset is particularly promising for longitudinal studies, incorporation of human behaviour into contaminant load models, or for recoding and analysis for themes other than those discussed by Georgakakos et al. [1].

Critical Review of Polyphosphate and Polyphosphate Accumulating Organisms for Agricultural Water Quality Management.

Despite ongoing management efforts, phosphorus (P) loading from agricultural landscapes continues to impair water quality. Wastewater treatment research has enhanced our knowledge of microbial mechanisms influencing P cycling, especially regarding microbes known as polyphosphate accumulating organisms (PAOs) that store P as polyphosphate (polyP) under oxic conditions and release P under anoxic conditions. However, there is limited application of PAO research to reduce agricultural P loading and improve water quality. Herein, we conducted a meta-analysis to identify articles in Web of Science on polyP and its use by PAOs across five disciplines (i.e., wastewater treatment, terrestrial, freshwater, marine, and agriculture). We also summarized research that provides preliminary support for PAO-mediated P cycling in natural habitats. Terrestrial, freshwater, marine, and agriculture disciplines had fewer polyP and PAO articles compared to wastewater treatment, with agriculture consistently having the least. Most meta-analysis articles did not overlap disciplines. We found preliminary support for PAOs in natural habitats and identified several knowledge gaps and research opportunities. There is an urgent need for interdisciplinary research linking PAOs, polyP, and oxygen availability with existing knowledge of P forms and cycling mechanisms in natural and agricultural environments to improve agricultural P management strategies and achieve water quality goals.

Farmer perceptions of dairy farm antibiotic use and transport pathways as determinants of contaminant loads to the environment.

Agricultural antibiotic contamination into milk and beef products has been considered extensively, but antibiotic transport into soil and water environments is less regulated and studied. Farmer perceptions of these transport processes are critical to understanding how antibiotics reach soils and surface waters and what management strategies can be implemented to reduce environmental antibiotic loads. We have conducted semi-structured interviews with twenty-seven dairy farmers in central New York to understand farmer perceptions of environmental transport of antibiotics and decisions that reduce environmental antibiotic loads. Interviews were qualitatively analyzed and coded using thematic analysis. We found that farmers extensively considered transport of antibiotics into milk and beef, while consideration of antibiotic transport into manure was less common, and no farmers discussed antibiotic transport from carcasses into soil from on-farm animal mortality. Farmers highlighted decisions that reduce antibiotic environmental loads through disease prevention actions, usage of non-antibiotic treatments, and culturing bacterial samples before antibiotic treatment. Farmers did not cite reduction of environmental antibiotic loads as a driver of their waste management decisions. Farmers perceived antibiotic usage was already minimized on farms in the region, suggesting future environmental antibiotic contamination mitigation strategies should focus on waste management pathways.

Hudson River juvenile Blueback herring avoid ingesting microplastics.

Microplastics in aquatic environments, and specifically their effects on the health of organisms, are of growing concern worldwide. Of particular concern are microplastics in a similar size range to zooplankton, as they have been found in the digestive tracks of organisms, such as fish, who typically seek zooplankton as a food source. It is unclear, however, to what degree, if any, fish select for or against microplastic particles when feeding. It is also unclear whether ingestion of microplastics affects fish condition. To answer these questions, the estimated physical condition and degree of selective feeding on microplastics were determined for juvenile fish collected from the Hudson River. Considering only particles 0.335-5.0 mm, microplastics made up 12% of fish diets but 21% of particles found in the surrounding water column. Relying on Jacob's Modified Electivity (JME) to quantify selectivity in feeding, our results reveal selective feeding on zooplankton and avoidance of microplastics. There was no correlation between condition and degree of selectivity toward any particular food types, including microplastics. Future work needs to consider fish with different feeding strategies and potential bioaccumulation of microplastics in the food web. Fish selectivity of ingestion in regards to microplastics should additionally be tested on wider spatial and temporal scales.

A case study investigating temporal factors that influence microplastic concentration in streams under different treatment regimes.

Microplastics, particles less than 5 mm in size, are an emerging contaminant in waterways worldwide. Most microplastic studies focus on spatial trends in concentration, but in systems as dynamic as rivers, to draw conclusions from existing spatial studies, we must first examine how microplastic concentrations may change with time and flow conditions. In this study, we investigate how microplastic concentrations change over a 24-h period and between seasonally high and low flows. We do this in two streams, controlling for wastewater treatment strategy: one stream in a watershed where waste is treated with septic systems and the other receiving wastewater treatment plant effluent. We hypothesized that a stream with wastewater treatment plant effluent would exhibit higher and more variable microplastic concentrations than a stream in a watershed with septic systems. Results indicate, however, that there is no significant difference between the two streams despite their differing treatment strategies. Additionally, no significant variation in concentrations was measured over two 24-h sampling campaigns. There was, however, significantly higher concentrations measured in summer low flow conditions relative to spring high flow conditions across both sampled streams (p value <0.001), indicating that increases in stream discharge unrelated to storm events dilute and decrease measured microplastic concentrations. From this, we learn that pairing measured concentrations with a description of flow conditions at sampling time is a requisite for a robust microplastic literature that allows for comparisons between existing spatial studies and extrapolations to global loads.

Metagenomic analysis reveals distinct patterns of denitrification gene abundance across soil moisture, nitrate gradients.

This study coupled a landscape-scale metagenomic survey of denitrification gene abundance in soils with in situ denitrification measurements to show how environmental factors shape distinct denitrification communities that exhibit varying denitrification activity. Across a hydrologic gradient, the distribution of total denitrification genes (nap/nar + nirK/nirS + cNor/qNor + nosZ) inferred from metagenomic read abundance exhibited no consistent patterns. However, when genes were considered independently, nirS, cNor and nosZ read abundance was positively associated with areas of higher soil moisture, higher nitrate and higher annual denitrification rates, whereas nirK and qNor read abundance was negatively associated with these factors. These results suggest that environmental conditions, in particular soil moisture and nitrate, select for distinct denitrification communities that are characterized by differential abundance of genes encoding apparently functionally redundant proteins. In contrast, taxonomic analysis did not identify notable variability in denitrifying community composition across sites. While the capacity to denitrify was ubiquitous across sites, denitrification genes with higher energetic costs, such as nirS and cNor, appear to confer a selective advantage in microbial communities experiencing more frequent soil saturation and greater nitrate inputs. This study suggests metagenomics can help identify denitrification hotspots that could be protected or enhanced to treat non-point source nitrogen pollution.

The effect of dams on river transport of microplastic pollution.

Dams are known to trap pollutants such as metals and PCBs in the sediment that accumulates within their reservoirs. As more attention is paid to microplastics, an emerging contaminant in waterways worldwide, and how they move along rivers, whether microplastic particles also accumulate behind dams is an important question for informing estimates of global river inputs to oceans. In this study, we measured microplastic concentrations above, below, and within the reservoirs of six dams near Ithaca, NY USA. Samples were processed following the wet peroxide oxidation method and visual counting, followed by Raman Spectroscopy validation. We found that microplastic concentrations in sediment within reservoirs was significantly higher than in sediment above the dams (p = 0.005), and in water samples, concentrations within reservoirs was significantly lower (p = 0.02). Plastic fibers were the dominant plastic type, but in within-reservoir sediment samples, less abundant plastic types such as plastic fragments were found in higher proportions. These results show that the sediment collecting behind dams is one sink for microplastics in river systems at long timescales, indicating that accounting for dams may be important when modeling global riverine microplastic transport.

The heavy metal budget of an urban rooftop farm.

Urban rooftop agriculture is a growing enterprise in the US with the goal of providing high quality, healthy, locally grown produce for city dwellers. However, air pollution abatement and the purification of stormwater are among the ecosystem services emphasized in studies of conventional green roofs. If rooftop farms actually capture pollutants, then accumulation of heavy metals in the soil could pose a problem over time. This study reports the heavy metal concentrations in soil, atmospheric deposition, and drainage output of 8 metals from the Brooklyn Grange Navy Yard Farm, rooftop vegetable farm in New York City, USA. Drainage of Pb and Mn were 6% and 14% of atmospheric bulk deposition, respectively, meaning that the Grange could be a net sink for Pb and Mn. Although there were small scale hotspots in the soil, farm-wide averages for heavy metal concentrations never exceeded guideline levels, and relatively low concentrations of Pb and Ba in the soil suggest that rooftop soils may be less vulnerable to contamination related to traffic and construction. In comparison to the growing seasons, we found relatively high concentrations of Pb and Cr in the soil during fallow periods when the soil was bare. To reduce the atmospheric deposition of heavy metals to soil, it is important to cover the soil with mulch, and discard the used mulch and unmarketable portion of vegetables, instead of recycling them via composting for soil amendments.

Absence of genetic selection in a pathogenic Escherichia coli strain exposed to the manure-amended soil environment.

Escherichia coli that express curli are more common in subsurface soil drainage when manure is surface applied. However, it is unknown whether this arises from mutations in individual strains leading to curli expression or by selection for individuals already expressing higher levels of curli. To test this, we examined curli production in pathogenic E. coli O157:H7 EDL933 as a function of manure management. Five treatments were investigated: (1) soil only, (2) soil with surface-applied E. coli O157:H7 EDL933 Δstx1-2 (EcO157), (3) soil with incorporated EcO157, (4) soil with surface-applied EcO157-inoculated manure, and (5) soil with incorporated EcO157-inoculated manure. EcO157 was reisolated from soils immediately after application and weekly thereafter for 8 weeks. EcO157 in the surface-applied treatments died faster than their incorporated treatment counterparts. Phenotypic assays revealed differences between treatments as well. Half of surface-applied manure reisolates from week 6 developed a mixed red and white colony morphology on Congo Red plates, indicating changes in curli production that were not seen in other treatments or times. In 37°C growth tests, week 6 reisolates from all treatments except soil surface-applied EcO157 left the lag phase at a significantly greater rate than week 0 isolates. We applied whole genome sequencing technology to interrogate the genetic underpinnings of these phenotypes. Surprisingly, we only found single-nucleotide polymorphisms in two of the 94 resequenced isolates from the different treatments, neither of which correlated with curli phenotype. Likewise, we found no differences in other genomic characteristics that might account for phenotypic differences including the count of gaps and the origin of discarded reads that failed to map to the parental strain. These results suggest there were no systematic genomic differences (i.e. individual-level selection) that correlated with time or treatment. We recommend future research focus on population-level selection of E. coli strains in the manure-amended soil environment.

Plant-Microbe Interactions Drive Denitrification Rates, Dissolved Nitrogen Removal, and the Abundance of Denitrification Genes in Stormwater Control Measures.

The microbial community and function along with nitrate/nitrite (NOx) removal rates, and nitrogen (N) partitioning into "uptake", "denitrification", and "remaining" via isotope tracers, were studied in soil bioretention mesocolumns (8 unique plant species). Total denitrification gene reads per million (rpm) were positively correlated with % denitrified ( r = 0.69) but negatively correlated with total NOx removal following simulated rain events ( r = -0.79). This is likely due to plant-microbe interactions. Plant species with greater root volume, plant and microbial assimilation %, and NOx removal % had lower denitrification genes and rates. This implies that although microorganisms have access to N, advantageous functions, like denitrification, may not increase. At the conclusion of the 1.5-year experiment, the microbial community was strongly influenced by plant species within the Top zone dominated by plant roots, and the presence or absence of a saturated zone influenced the microbial community within the Bottom zone. Leptospermum continentale was an outlier from the other plants and had much lower denitrification gene rpm (average 228) compared to the other species (range: 277 to 413). The antimicrobial properties and large root volume of Leptospermum continentale likely caused this denitrification gene depression.

Effects of urbanization on direct runoff characteristics in urban functional zones.

As urbanization processes, the increasing direct runoff caused by land use change has become a major challenge for urban hydrological system. In this study, the impact of urbanization on direct runoff in the Shenyang urban area was investigated using a modified Soil Conservation Service Curve Number model combined with remote sensing. Urban functional zone (UFZ) was used as the basic unit for hydrological analysis. The hydrological changes in runoff were analyzed by calculating the runoff difference between the current condition and the pre-urbanization condition. Moran's I was used to estimate the spatial autocorrelation of the entire area. Then we assessed the relative influence and marginal effects of factors affecting direct runoff using boosted regression trees (BRT). Our results showed that direct runoff was significantly related to urbanization. Under current conditions, direct runoff increment depth affected by urbanization in the study area was 68.02 mm. For different UFZs, high-density residential, business and industrial zones tended to have large runoff volumes and high runoff coefficients. Through flooding hazard analysis, we found about 6.53% of the study area fell into a significant hazard category. The industrial zone had largest area of significant hazard land (40.97 km2) and the business zone had the largest significant hazard percentage (21.19%). Moran's I results illustrated that the high-high clusters in Shenyang were mainly concentrated in the urban center. BRT analysis indicated that runoff had the strongest correlation with rainfall (52.07%), followed by impervious ratio (27.28%), normalized difference vegetation index (14.31%), antecedent 5-day rainfall (3.02%), and UFZs (1.70%). The industrial zone, business zone and high-density residential zone tend to have greater influence on runoff. Our study could present method for recognizing hotspots of direct runoff in large city, and may provide potential implications for green infrastructure selection and urban planning.

Methane and nitrous oxide cycling microbial communities in soils above septic leach fields: Abundances with depth and correlations with net surface emissions.

Onsite septic systems use soil microbial communities to treat wastewater, in the process creating potent greenhouse gases (GHGs): methane (CH4) and nitrous oxide (N2O). Subsurface soil dispersal systems of septic tank overflow, known as leach fields, are an important part of wastewater treatment and have the potential to contribute significantly to GHG cycling. This study aimed to characterize soil microbial communities associated with leach field systems and quantify the abundance and distribution of microbial populations involved in CH4 and N2O cycling. Functional genes were used to target populations producing and consuming GHGs, specifically methyl coenzyme M reductase (mcrA) and particulate methane monooxygenase (pmoA) for CH4 and nitric oxide reductase (cnorB) and nitrous oxide reductase (nosZ) for N2O. All biomarker genes were found in all soil samples regardless of treatment (leach field, sand filter, or control) or depth (surface or subsurface). In general, biomarker genes were more abundant in surface soils than subsurface soils suggesting the majority of GHG cycling is occurring in near-surface soils. Ratios of production to consumption gene abundances showed a positive relationship with CH4 emissions (mcrA:pmoA, p < 0.001) but not with N2O emission (cnorB:nosZ, p > 0.05). Of the three measured soil parameters (volumetric water content (VWC), temperature, and conductivity), only VWC was significantly correlated to a biomarker gene, mcrA (p = 0.0398) but not pmoA or either of the N2O cycling genes (p > 0.05 for cnorB and nosZ). 16S rRNA amplicon library sequencing results revealed soil VWC, CH4 flux and N2O flux together explained 64% of the microbial community diversity between samples. Sequencing of mcrA and pmoA amplicon libraries revealed treatment had little effect on diversity of CH4 cycling organisms. Overall, these results suggest GHG cycling occurs in all soils regardless of whether or not they are associated with a leach field system.

Fabrication, detection, and analysis of DNA-labeled PLGA particles for environmental transport studies.

Poly(lactic-co-glycolic acid) (PLGA) particle carriers of synthetic DNA have recently received increased attention for environmental applications due to their biodegradability, customizability, and nearly limitless number of uniquely identifiable "labels". In this paper, we present methodologies for the preparation of DNA-labeled particles, control of particle size, extraction of DNA-labels, and analysis via quantitative polymerase chain reaction (qPCR). Characterization and analysis of the DNA-labeled particles reveal spherical particles of diameters ranging from 60 to 1000 nm, with consistent zeta potentials around -45 mV, that are stable to aggregation, even in the presence of concentrated mono- and divalent cations. A highly correlated and consistent relationship between particle concentration and DNA-label count was observed, with a detection range spanning 7 orders of magnitude, from 0.01 to 10,000 mg/L (10-107 particles/µL). The results of two environmental applications of the DNA-labeled particles are also presented, highlighting their feasibility for use in environmental studies. Whether exploring size-dependent transport phenomena or identifying potential pathogen transport pathways, the DNA-labeled particle approach presented here provides a powerful tool for the identification of overlapping particle signals at a range of concentrations.