Autonomous screening of groundwater remediation technologies in the subsurface using the In Situ Microcosm Array (ISMA).

The groundwater remediation industry continues to progress towards less expensive, more sustainable in situ remedies. However, in situ treatment requires site-specific performance data that can be difficult or impossible to obtain using conventional laboratory microcosm studies. To improve the representativeness of laboratory scale treatability studies, and aid in remedial technology implementation, we developed the In Situ Microcosm Array (ISMA). This autonomous diagnostic device enables the deployment of 10 flow-through sediment columns within a standard 10-cm groundwater-monitoring well. Suspended at the desired aquifer depth, the fully encapsulated ISMA meters groundwater directly from the aquifer to microcosms containing competing remedial technologies. Field demonstrations of the instrument were performed in two aquifers contaminated, respectively, with trichloroethylene and hexavalent chromium, and with perchlorate. A cost assessment positions ISMA deployment costs within the range of conventional laboratory treatability studies. Results demonstrate the ISMA's utility to perform cost-effective, high-throughput, screenings of multiple intervention strategies in the field, without impacting the subsurface environment examined.

Pharmaceuticals and personal care products in archived U.S. biosolids from the 2001 EPA National Sewage Sludge Survey.

In response to the U.S. National Academies' call for a better assessment of chemical pollutants contained in the approximately 7 million dry tons of digested municipal sludge produced annually in the United States, the mean concentration of 72 pharmaceuticals and personal care products (PPCP) were determined in 110 biosolids samples collected by the U.S. Environmental Protection Agency (EPA) in its 2001 National Sewage Sludge Survey. Composite samples of archived biosolids, collected at 94 U.S. wastewater treatment plants from 32 states and the District of Columbia, were analyzed by liquid chromatography tandem mass spectrometry using EPA Method 1694. Thirty-eight (54%) of the 72 analytes were detected in at least one composite sample at concentrations ranging from 0.002 to 48 mg kg(-1) dry weight. Triclocarban and triclosan were the most abundant analytes with mean concentrations of 36 +/- 8 and 12.6 +/- 3.8 mg kg(-1) (n = 5), respectively, accounting for 65% of the total PPCP mass found. The loading to U.S. soils from nationwide biosolids recycling was estimated at 210-250 metric tons per year for the sum of the 72 PPCPs investigated. The results of this nationwide reconnaissance of PPCPs in archived U.S. biosolids mirror in contaminant occurrences, frequencies and concentrations, those reported by the U.S. EPA for samples collected in 2006/2007. This demonstrates that PPCP releases in U.S. biosolids have been ongoing for many years and the most abundant PPCPs appear to show limited fluctuations in mass over time when assessed on a nationwide basis. The here demonstrated use of five mega composite samples holds promise for conducting cost-effective, routine monitoring on a regional and national basis.

Occurrence and loss over three years of 72 pharmaceuticals and personal care products from biosolids-soil mixtures in outdoor mesocosms.

Municipal biosolids are in widespread use as additives to agricultural soils in the United States. Although it is well known that digested sewage sludge is laden with organic wastewater contaminants, the fate and behavior of micropollutants in biosolids-amended agricultural soils remain unclear. An outdoor mesocosm study was conducted in Baltimore, Maryland, to explore the fate of 72 pharmaceuticals and personal care products (PPCPs) over the course of three years in that were placed in plastic containers made from polyvinylchloride and kept exposed to ambient outdoor conditions. Of the 72 PPCPs tested for using EPA Method 1694, 15 were initially detected in the soil/biosolids mixtures at concentrations ranging from low parts-per-billion to parts-per-million levels. The antimicrobials triclocarban and triclosan showed the highest initial concentrations at 2715 and 1265 µg kg(-1), respectively. Compounds showing no discernable loss over three years of monitoring included diphenhydramine, fluoxetine, thiabendazole and triclocarban. The following half-life estimates were obtained for compounds showing first-order loss rates: azithromycin (408-990 d) carbamazepine (462-533 d), ciprofloxacin (1155-3466 d), doxycycline (533-578 d), 4-epitetracycline (630 d), gemfibrozil (224-231 d), norfloxacin (990-1386 d), tetracycline (578 d), and triclosan (182-193 d). Consistent with other outdoor degradation studies, chemical half-lives determined empirically exceeded those reported from laboratory studies or predicted from fate models. Study results suggest that PPCPs shown in the laboratory to be readily biotransformable can persist in soils for extended periods of time when applied in biosolids. This study provides the first experimental data on the persistence in biosolids-amended soils for ciprofloxacin, diphenhydramine, doxycycline, 4-epitetracycline, gemfibrozil, miconazole, norfloxacin, ofloxacin, and thiabendazole.