United States National Sewage Sludge Repository at Arizona State University—a new resource and research tool for environmental scientists, engineers, and epidemiologists

Abstract

Processed municipal sewage sludges (MSS) are an abundant, unwanted by-product of wastewater treatment, increasingly applied to agriculture and forestry for inexpensive disposal and soil conditioning. Due to their high organic-carbon and lipid contents, MSS not only is rich in carbon and nutrients but also represents a ‘sink’ for recalcitrant, hydrophobic and potentially bioaccumulative compounds. Indeed, many organics sequestered and concentrated in MSS meet the U.S. Environmental Protection Agency's definition of being persistent, bioaccumulative, and toxic (PBT). In a strategic effort, our research team at the Biodesign Institute has created the National Sewage Sludge Repository (NSSR), a large repository of digested MSSs from 164 wastewater treatment plants from across the USA, as part of the Human Health Observatory (H2O) at Arizona State University (ASU). The NSSR likely represents the largest archive of digested MSS specimens in the USA. The present study summarizes key findings gleaned thus far from analysis of NSSR samples. For example, we evaluated the content of toxicants in MSS and computed estimates of nationwide inventories of mass produced chemicals that become sequestrated in sludge and later are released into the environment during sludge disposal on land. Ongoing efforts document co-occurrence of a variety of PBT compounds in both MSS and human samples, while also identifying a large number of potentially harmful MSS constituents for which human exposure data are still lacking. Finally, we summarize new future opportunities and invite collaborative use the NSSR by the research community. The H2O at ASU represents a resource and research tool for environmental scientists and the larger research community. As illustrated in this work, this repository can serve to (i) identify and prioritize emerging contaminants; (ii) provide spatial and temporal trends of contaminants; (iii) inform and evaluate the effectiveness of environmental policy-making and regulations; and (iv) approximate, ongoing exposures and body burdens of mass-produced chemicals in human society.

Occurrence and estrogenic potency of eight bisphenol analogs in sewage sludge from the U.S. EPA targeted national sewage sludge survey

“…Two samples were collected at ten POTWs, either because the facility had more than one treatment system and produced two types of final SS, or for quality assurance purposes, as well as one single grab sample at the remaining 64 facilities (Table S1). After the completion of TNSSS, the samples were acquired by the Halden Laboratory and archived at -20 o C as part of the Human Health Observatory (H2O) and National Sewage Sludge Repository (NSSR) at Arizona State University [36]. Eight samples were either missing or broken during shipment and handling.…”

“…In that study, SS samples were collected from 74 POTWs that employ secondary treatment or better in 2006/2007 [35]. Several pollutants have been analyzed 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 5 in these samples and the results have been published [29,[36][37][38][39]. However, no earlier study has reported the occurrence of bisphenols in SS from nationally representative samples.…”

Modeling the pH-mediated extraction of ionizable organic contaminants to improve the quality of municipal sewage sludge destined for land application

“…EPA 2007, 2009; Venkatesan et al, 2014a). These representative samples were collected from more than 160 WWTPs across the contiguous United States.…”

“…The number of hazardous chemicals detected in MSS is considerable and constantly increasing (U.S. EPA, 2009; Venkatesan et al, 2014a, 2014b). Many of these contaminants are known endocrine disruptors, carcinogens and potent toxicants to aquatic organisms and humans.…”

“…In addition, a new emerging concern is the presence in MSS of significant quantities of important antibiotics (e.g., ciprofloxacin) that are known to promote antibiotic resistance in human pathogens even when present at nontherapeutic concentrations (Martins da Costa et al, 2006; Pruden, 2013; Reinthaler et al, 2003). Prior screening for 239 contaminants in nationally representative samples of MSS collected from more than 160 U.S. WWTPs, showed the presence of 130 contaminants of emerging concern (CECs) in U.S. biosolids with detection frequency varying between 20 and 100% in the samples analyzed (Venkatesan et al, 2014a,b). Chemicals detected were calculated to contribute about 0.04–0.15% of the total dry mass of MSS produced in the U.S. annually, a mass equivalent to 0.4–1.5 g/kg of dry MSS or about 4,700 t (range: 2,600–7,900 t) of chemicals annually.…”