Climatic variability, hydrologic anomaly, and methane emission can turn productive freshwater marshes into net carbon sources.

Freshwater marshes are well-known for their ecological functions in carbon sequestration, but complete carbon budgets that include both methane (CH4 ) and lateral carbon fluxes for these ecosystems are rarely available. To the best of our knowledge, this is the first full carbon balance for a freshwater marsh where vertical gaseous [carbon dioxide (CO2 ) and CH4 ] and lateral hydrologic fluxes (dissolved and particulate organic carbon) have been simultaneously measured for multiple years (2011-2013). Carbon accumulation in the sediments suggested that the marsh was a long-term carbon sink and accumulated ~96.9 ± 10.3 (±95% CI) g C m(-2)  yr(-1) during the last ~50 years. However, abnormal climate conditions in the last 3 years turned the marsh to a source of carbon (42.7 ± 23.4 g C m(-2)  yr(-1) ). Gross ecosystem production and ecosystem respiration were the two largest fluxes in the annual carbon budget. Yet, these two fluxes compensated each other to a large extent and led to the marsh being a CO2 sink in 2011 (-78.8 ± 33.6 g C m(-2)  yr(-1) ), near CO2 -neutral in 2012 (29.7 ± 37.2 g C m(-2)  yr(-1) ), and a CO2 source in 2013 (92.9 ± 28.0 g C m(-2)  yr(-1) ). The CH4 emission was consistently high with a three-year average of 50.8 ± 1.0 g C m(-2)  yr(-1) . Considerable hydrologic carbon flowed laterally both into and out of the marsh (108.3 ± 5.4 and 86.2 ± 10.5 g C m(-2)  yr(-1) , respectively). In total, hydrologic carbon fluxes contributed ~23 ± 13 g C m(-2)  yr(-1) to the three-year carbon budget. Our findings highlight the importance of lateral hydrologic inflows/outflows in wetland carbon budgets, especially in those characterized by a flow-through hydrologic regime. In addition, different carbon fluxes responded unequally to climate variability/anomalies and, thus, the total carbon budgets may vary drastically among years.

Particulate matter (PM) exposure assessment--horizontal and vertical PM profiles in relation to agricultural activities and environmental factors in farm fields.

Reports profiling airborne particulate matter (PM) in farm fields, especially during a Class B biosolids land-injection process, are scarce. Thus, this study characterized PM in such a farm field located in northwest Ohio. For comparison, a control farm field with no biosolids application history was also monitored. During 11 days of varied agricultural activities, the concentrations of particle mass and number (count) and also metal content were monitored in the study field, and their interactions with environmental factors were examined. The monitoring was performed across the farm field at four heights of 0.5, 1.5, 2.5, and 3.5 m from the ground. The overall mean (SD) concentration (µg/m(3)) of respirable suspended particulate matter (RPM) was 30.8 (23.1) with means ranging from 15.9 (3.80) during post-tilling Event 1, 19.9 (12.4) during biosolids application to 56.1 (11.7) during post-harvest (including baling) activity. The maximum concentration of RPM (µg/m(3)) was 43 during biosolids application, 90 during post-harvest, and 183 during post-tilling Event 2 activities. Overall, 93.7% (8.98%) of the total suspended particulate matter (TPM) was respirable. The levels of RPM significantly (p < 0.01) correlated with TPM and particle counts of ultrafine particles (UFP) and 0.3 µm particle size. Ambient temperature showed no effect, whereas wind speed and relative humidity had an inverse effect on RPM concentration. Particle concentrations changed minimally during each set of monitoring across the field, except during major activities or sudden weather changes. For particles with sizes of 2, 5, and 10 µm, the counts decreased with increasing height from the ground and were significantly (p < 0.05) higher at 0.5 m than at other heights. The levels of nine metals within particles monitored were well below current recommended occupational exposure criteria. These results suggest that injection of the biosolids into agricultural land provides significant protection against exposure to biosolids particles.

Uptake of pharmaceutical and personal care products by soybean plants from soils applied with biosolids and irrigated with contaminated water.

Many pharmaceuticals and personal care products (PPCPs) are commonly found in biosolids and effluents from wastewater treatment plants. Land application of these biosolids and the reclamation of treated wastewater can transfer those PPCPs into the terrestrial and aquatic environments, giving rise to potential accumulation in plants. In this work, a greenhouse experiment was used to study the uptake of three pharmaceuticals (carbamazepine, diphenhydramine, and fluoxetine) and two personal care products (triclosan and triclocarban) by an agriculturally important species, soybean (Glycine max (L.) Merr.). Two treatments simulating biosolids application and wastewater irrigation were investigated. After growing for 60 and 110 days, plant tissues and soils were analyzed for target compounds. Carbamazepine, triclosan, and triclocarban were found to be concentrated in root tissues and translocated into above ground parts including beans, whereas accumulation and translocation for diphenhydramine and fluoxetine was limited. The uptake of selected compounds differed by treatment, with biosolids application resulting in higher plant concentrations, likely due to higher loading. However, compounds introduced by irrigation appeared to be more available for uptake and translocation. Degradation is the main mechanism for the dissipation of selected compounds in biosolids applied soils, and the presence of soybean plants had no significant effect on sorption. Data from two different harvests suggest that the uptake from soil to root and translocation from root to leaf may be rate limited for triclosan and triclocarban and metabolism may occur within the plant for carbamazepine.

Dissipation and leaching potential of selected pharmaceutically active compounds in soils amended with biosolids.

Biosolids land application is an important pathway introducing pharmaceuticals into the environment. In this work, laboratory column and dissipation experiments were performed using soils of varying properties in order to study the fate and transport of pharmaceutical residues introduced by the land application of biosolids. For experimentation, five pharmaceutical compounds (carbamazepine, diphenhydramine, fluoxetine, diltiazem, and clindamycin) and two metabolites (carbamazepine-10,11-epoxide and norfluoxetine) commonly found in biosolids were selected. Leaching experiments indicate that the selected pharmaceuticals have low mobility in tested soils. However, small portions of the applied pharmaceuticals were recovered in the leachates, likely attributed to sorption to dissolved organic matter. Dissipation experiments show that carbamazepine, diphenhydramine, and fluoxetine were persistent in soils, whereas the dissipation of diltiazem and clindamycin was affected by redox conditions and soil properties.

Genetic evidence for the offsite transport of E. coli associated with land application of Class B biosolids on agricultural fields.

The land-application of Class B biosolids is tightly regulated to allow for natural attenuation of co-applied pathogens. Since many agricultural fields that receive biosolids are artificially drained through subsurface tiles, it is possible that under scenarios of excessive drainage associated with heavy rainfall events, co-applied pathogens might be carried offsite to contaminate nearby surface waters. To address this concern, we used genetic as well as traditional methods to investigate the impact of rainfall on the offsite drainage of Escherichia coli from agricultural fields during biosolids application. Water samples from field drain tiles and a reference field (no biosolids applied) were collected pre-, during and post-biosolids application, while samples of applied biosolids were collected on site during application. The samples were analyzed for E. coli-density and community- and isolate-fingerprinting to assess the genetic link between E. coli in drainage water and those co-applied with biosolids. In contrast to E. coli densities present in the reference field drainage, our results revealed that post-application drainage water collected from biosolids treated fields contained significantly higher E. coli densities following heavy rainfall events, as compared to light rainfall events. Also, in contrast to the reference field, heavy rainfall correlated significantly with increased similarity of E. coli community fingerprints occurring in biosolids to those draining from treated field. Fingerprinting of individual E. coli revealed a high similarity (>94%) between some isolates collected from biosolids and post-application drainage water. Using a combination of enumeration and genetic typing methods, we show that heavy rainfall following biosolids application to agricultural fields induced the offsite transport of biosolids-associated E. coli, potentially compromising the quality of water draining through the watershed.

Occurrence of selected pharmaceuticals in an agricultural landscape, western Lake Erie basin.

The occurrence of 18 commonly used pharmaceuticals was investigated in an agricultural area, which is primarily affected by runoff from agricultural fields and septic systems, on the coastline of Maumee Bay, within the western Lake Erie basin. Selected pharmaceuticals were detected in surface water, except clofibric acid and fluoxethine. The most frequently detected compounds were caffeine (88%), carbamazepine (57%) and paraxanthine (56%). Caffeine, carbamazepine, ibuprofen and paraxanthine were detected with maximum concentrations of 4.2, 1.2, 2.8 and 1.8 microg L(-1), respectively. However, no compound was detected in any sediment samples. In a field receiving biosolids application, pharmaceuticals were detected in the field tile drainage following biosolids application but not in soil. The occurrence of pharmaceuticals in surface water can be linked to the use of septic systems.

Health survey of residents living near farm fields permitted to receive biosolids.

The authors studied the health status of residents living in Wood County, OH, near farm fields that were permitted to receive biosolids. They mailed a health survey to 607 households and received completed surveys from 437 people exposed to biosolids (living on or within 1 mile of the fields where application was permitted) and from 176 people not exposed to biosolids (living more than 1 mile from the fields where application was permitted). The authors allowed for up to 6 surveys per household. Results revealed that some reported health-related symptoms were statistically significantly elevated among the exposed residents, including excessive secretion of tears, abdominal bloating, jaundice, skin ulcer, dehydration, weight loss, and general weakness. The frequency of reported occurrence of bronchitis, upper respiratory infection, and giardiasis were also statistically significantly elevated. The findings suggest an increased risk for certain respiratory, gastrointestinal, and other diseases among residents living near farm fields on which the use of biosolids was permitted. However, further studies are needed to address the limitations cited in this study.