April Ames

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.

Crystalline Silica Dust and Respirable Particulate Matter During Indoor Concrete Grinding—Wet Grinding and Ventilated Grinding Compared with Uncontrolled Conventional Grinding

The effectiveness of wet grinding (wet dust reduction method) and ventilated grinding (local exhaust ventilation method, LEV) in reducing the levels of respirable crystalline silica dust (quartz) and respirable suspended particulate matter (RSP) were compared with that of uncontrolled (no dust reduction method) conventional grinding. A field laboratory was set up to simulate concrete surface grinding using hand-held angle grinders in an enclosed workplace. A total of 34 personal samples (16 pairs side-by-side and 2 singles) and 5 background air samples were collected during 18 concrete grinding sessions ranging from 15–93 min. General ventilation had no statistically significant effect on operators exposure to dust. Overall, the arithmetic mean concentrations of respirable crystalline silica dust and RSP in personal air samples during: (i) five sessions of uncontrolled conventional grinding were respectively 61.7 and 611 mg/m 3 (ii) seven sessions of wet grinding were 0.896 and 11.9 mg/m3 and (iii) six sessions of LEV grinding were 0.155 and 1.99 mg/m3. Uncontrolled conventional grinding generated relatively high levels of respirable silica dust and proportionally high levels of RSP. Wet grinding was effective in reducing the geometric mean concentrations of respirable silica dust 98.2% and RSP 97.6%. LEV grinding was even more effective and reduced the geometric mean concentrations of respirable silica dust 99.7% and RSP 99.6%. Nevertheless, the average level of respirable silica dust (i) during wet grinding was 0.959 mg/m3 (38 times the American Conference of Governmental Industrial Hygienists [ACGIH] threshold limit value [TLV] of 0.025 mg/m 3 ) and (ii) during LEV grinding was 0.155 mg/m 3 (6 times the ACGIH TLV). Further studies are needed to examine the effectiveness of a greater variety of models, types, and sizes of grinders on different types of cement in different positions and also to test the simulated field lab experimentation in the field.

Effectiveness of Dust Control Methods for Crystalline Silica and Respirable Suspended Particulate Matter Exposure During Manual Concrete Surface Grinding

Concrete grinding exposes workers to unacceptable levels of crystalline silica dust, known to cause diseases such as silicosis and possibly lung cancer. This study examined the influence of major factors of exposure and effectiveness of existing dust control methods by simulating field concrete grinding in an enclosed workplace laboratory. Air was monitored during 201 concrete grinding sessions while using a variety of grinders, accessories, and existing dust control methods, including general ventilation (GV), local exhaust ventilation (LEV), and wet grinding. Task-specific geometric mean (GM) of respirable crystalline silica dust concentrations (mg/m 3 for LEV:HEPA-, LEV:Shop-vac-, wet-, and uncontrolled-grinding, while GV was off/on, were 0.17/0.09, 0.57/0.13, 1.11/0.44, and 23.1/6.80, respectively. Silica dust concentrations (mg/m 3 using 100–125 mm (4–5 inch) and 180 mm (7 inch) grinding cups were 0.53/0.22 and 2.43/0.56, respectively. GM concentrations of silica dust were significantly lower for (1) GV on (66.0%) vs. off, and (2) LEV:HEPA- (99.0%), LEV:Shop-vac- (98.1%) or wet- (94.4%) vs. uncontrolled-grinding. Task-specific GM of respirable suspended particulate matter (RSP) concentrations (mg/m 3 for LEV:HEPA-, LEV:Shop-vac-, wet-, and uncontrolled grinding, while GV was off/on, were 1.58/0.63, 7.20/1.15, 9.52/4.13, and 152/47.8, respectively. GM concentrations of RSP using 100–125 mm and 180 mm grinding cups were 4.78/1.62 and 22.2/5.06, respectively. GM concentrations of RSP were significantly lower for (1) GV on (70.2%) vs. off, and (2) LEV:HEPA- (98.9%), LEV:Shop-vac- (96.9%) or wet- (92.6%) vs. uncontrolled grinding. Silica dust and RSP were not significantly affected by (1) orientation of grinding surfaces (vertical vs. inclined); (2) water flow rates for wet grinding; (3) length of task-specific sampling time; or, (4) among cup sizes of 100, 115 or 125 mm. No combination of factors or control methods reduced an 8-hr exposure level to below the recommended criterion of 0.025 mg/m 3 for crystalline silica, requiring further refinement in engineering controls, administrative controls, or the use of respirators.

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/m3) 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/m3) 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.

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.

Task-Specific Noise Exposure During Manual Concrete Surface Grinding in Enclosed Areas—Influence of Operation Variables and Dust Control Methods

Noise exposure is a distinct hazard during hand-held concrete grinding activities, and its assessment is challenging because of the many variables involved. Noise dosimeters were used to examine the extent of personal noise exposure while concrete grinding was performed with a variety of grinder sizes, types, accessories, and available dust control methods. Noise monitoring was conducted in an enclosed area covering 52 task-specific grinding sessions lasting from 6 to 72 minutes. Noise levels, either in minute average noise level (Lavg, dBA) or in minute peak (dBC), during concrete grinding were significantly (P < 0.01) correlated with general ventilation (GV: on, off), dust control methods (uncontrolled, wet, Shop-Vac, HEPA, HEPA-Cyclone), grinding cup wheel (blade) sizes of 4-inch (100 mm), 5-inch (125 mm) and 6-inch (150 mm), and surface orientation (horizontal, inclined). Overall, minute Lavg during grinding was 97.0 ± 3.3 (mean ± SD), ranging from 87.9 to 113. The levels of minute Lavg during uncontrolled grinding (98.9 ± 5.2) or wet-grinding (98.5 ± 2.7) were significantly higher than those during local exhaust ventilation (LEV) grinding (96.2 ± 2.8). A 6-inch grinding cup wheel generated significantly higher noise levels (98.7 ± 2.8) than 5-inch (96.3 ± 3.2) or 4-inch (95.3 ± 3.5) cup wheels. The minute peak noise levels (dBC) during grinding was 113 ± 5.2 ranging from 104 to 153. The minute peak noise levels during uncontrolled grinding (119 ± 10.2) were significantly higher than those during wet-grinding (115 ± 4.5) and LEV-grinding (112 ± 3.4). A 6-inch grinding cup wheel generated significantly higher minute peak noise levels (115 ± 5.3) than 5-inch (112 ± 4.5) or 4-inch (111 ± 5.4) cup wheels. Assuming an 8-hour work shift, the results indicated that noise exposure levels during concrete grinding in enclosed areas exceeded the recommended permissible exposure limits and workers should be protected by engineering control methods, safe work practices, and/or personal protective devices.

Application of GIS in Evaluating the Potential Impacts of Land Application of Biosolids on Human Health

This chapter describes the development and use of a geographic information system (GIS) in an environmental health investigation of the application of Class B biosolids (sewage sludge) on agricultural fields. The research project is broad-based including field observations and modeling to investigate the presence of microorganisms, metals, and pharmaceutical and personal care products (PPCPs) in biosolids applied agricultural fields and the associated runoff. These data has been linked with remote sensing imagery and added to GIS layers for Wood, Lucas and Greene Counties in Ohio. Specifically, this project describes the way in which a GIS was developed and utilized with a mailed, epidemiological health survey to investigate the potential impact of biosolids application to agricultural fields in relation to self-reported human health symptoms, acute diseases and chronic diseases among groups of individuals living specified distances from fields where biosolids were permitted and applied. For Wood County, of the 24 symptoms in the survey, six were statistically higher near biosolids permitted fields and of the 29 diseases in the survey, five were statistically higher near biosolids permitted fields. The Lucas and Greene County surveys are still being analyzed. Our future work includes refinement of the spatial analysis and health survey to include the application of biosolids and the constituents of the biosolids to fields, distances to any farm field and to other potential relationships to health effects.