Duration: 10/01/2000 to 09/30/2005

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Statement of Issues and Justification

Sewage biosolids are a byproduct of water purification. To a large degree, these materials have traditionally been considered waste materials and dealt with accordingly (e.g., buried in landfills, dumped in the oceans). In part due to the environmental degradation resulting from such actions, plus the fact that these materials contain plant-available nutrients and organic matter useful in improving soil structure, recycling these materials through land application is increasingly being viewed as desirable. Simplistically, one might assume that these substances could be considered to be equivalent to commonly used fertilizers and applied to field sites accordingly. Yet, complications with the reasonably simple act of substituting these materials for traditional fertilizers result from their content of inorganic (e.g., heavy metals), organic (e.g., surfactants, solvents), and public health (e.g., viruses and other pathogens) contaminants and variability and uncertainty regarding the availability of nutrients.





Use of sewage biosolids via agricultural land application is increasing in the U.S. IN New York State, beneficial use increased from 5% in 1989 to over 50% in 1998 (NYS Department of Environmental Conservation, 1998). This trend is expected to continue. USEPA predicts that in the year 2010 70% of sewage biosolids or 5.7 million dry tons will be beneficially used as compared to 63% or 4.5 million dry tons in 2000 (USEPA, 1999). These materials have been used to supplement agricultural phosphorus and nitrogen sources, to adjust soil pH, and to enhance soil structure and tilth. However, a variety of concerns have been raised that must be resolved to ensure the long-term utility of sewage biosolids as well as the preservation of the limited resources of high quality agricultural soils, particularly under Northeast soil conditions. These concerns include questions of whether currently accepted usage practices (as prescribed by the USEPA 503 standards) are adequate to protect the quality of the soils characteristic of this region, to insure the safety of the crops produced thereon, and to protect groundwater.



Soils of the Northeast tend to be shallow and acidic, making them more sensitive to metal applications than are soils in the Midwest or Western U.S. Furthermore, many crops crucial to Northeastern agriculture (e.g., leguminous forage crops and vegetables) are more sensitive to soil metal contamination than the relatively metal-insensitive crops (e.g., corn) for which most phyotoxicity data have been collected. Dairy is a predominant agricultural industry in many Northeastern states and the sensitivity of ruminant animals to some contaminants such as molybdenum is an important consideration. In addition to these agricultural production concerns, there are questions of potential degradation of groundwater quality. Again this is a particular problem in the Northeastern region due to soil and groundwater conditions, its complex mosaic of high population centers and adjacent agricultural enterprises and the predominant use of private wells to supply water to rural residents. Unanswered concerns relating to mobility of metals and/or pathogens by preferential flow paths in soils receiving sewage biosolids and the impact of currently unregulated toxic organic and inorganic constituents are of particular concern in light of the reliance on groundwater sources.



These concerns highlight the possibility that more protective guidelines for long-term sludge use may be needed for the Northeast compared to other regions with different environmental characteristics. It is therefore of considerable utility and interest to define the conditions under which use of sewage biosolids under Northeastern conditions are beneficial and to define procedures for their processing and utilization that will not compromise the current and future usefulness of soils or groundwater. Achievement of the objectives of this project will contribute to the necessary database for development of appropriate management practices for such conditions.



The variability in composition of sewage biosolids - both of desired nutrients as well as contaminants - is an important factor in management decisions regarding land application. Variability includes differences between wastewater treatment facilities as well as temporal fluctuations from a single sewage treatment plant (STP). Sampling frequencies required under current regulations may be as low as one or two samples per year, depending on the capacity of the treatment facility. An understanding of temporal variability at a facility is necessary for making sound land application decisions (for example, application rates should be based on agronomic rates which depend on nitrogen content and availability, variables which may fluctuate significantly). The adequacy of this frequency of monitoring for making such determinations is unknown.

Regulators, faculty, specialists and extension agents are receiving increasing numbers of inquiries regarding safety, social, and economic issues associated with land application of sewage biosolids. While scientific data are useful in determining the risk of the land application of biosolids, additional social information is required to provide adequate responses to questions regarding "perceived risks" and their implications for all potential stakeholders.



To address the issues cited above, a multi-institution, multidisciplinary, integrated research and extension project is proposed wherein well-documented field sites with histories of long-term sludge application will be examined cooperatively. Emphasis will be placed on assessing sites for soil and water quality, plant growth, and pathogen survival and mobility. Social and political impacts will also be assessed. These data plus existing records will be used to assess: sewage biosolids variability; environmental, agricultural and social impacts of varied application scenarios; and the larger sociopolitical contexts in which land application takes place.



While much scientific research has been accomplished and more is on-going (W-170 project, for example), important questions remain that need to be answered. These include further definition of the suitable loading rates of trace metals (e.g., cadmium, copper, mercury, molybdenum, nickel, lead and zinc) which are regulated by their potential for plant or human toxicity and the presence and risks posed by other toxic inorganic and organic chemicals that are not currently regulated and therefore infrequently monitored, if at all, by producers or land owners recycling sludges. Although frequently considered to be a "non-issue," there is also a growing interest in survival of pathogens, particularly viruses, in sludge materials and receiving soils (Chaprone and Margolin, 2000; Yates and Ouyang, 1992). Each of these concerns is exacerbated by the possible movement into ground and nearby surface waters and/or their incorporation into animal and human food systems.



Because of the continuing controversy regarding land application of sewage sludges, all stakeholders involved with their management (e.g., growers, communities, regulating agencies, scientists, and neighbors) in the Northeast are increasingly seeking information and guidance from the land grant universities. However, currently such guidance is inconsistent due to varied interpretations of the limited data available describing use of such materials on shallow, acidic soils and the need to extrapolate findings from studies of unrelated soil systems. This results in confusion and weakens the impact of the advice provided by the extension services of the land grant universities.



Areas of particular concern are:

1. Trace elements
2. Nonylphenols
3. Groundwater
   
   
4. Nutrients
5. Pathogens
6. Social, political and legal impacts
   
   

Trace Elements

Concentrations of some trace metals in sewage biosolids have been reduced substantially over the past several decades by improved source management and pretreatment of substances entering the wastewater stream. Yet, concerns remain regarding potential for excessive application of some contaminants from sewage biosolids to susceptible Northeastern soil and crop systems under the existing federal rules (McBride, 1995; Schmidt, 1997; Harrison et al., 1999). Interrelated concerns involving the implications of the trace element contents of biosolids on agricultural soils include not only considerations of the fate of the metals themselves and in crops, but also their impacts on the stability and sustainability of the soil ecosystem itself. For example, it has been shown that measurable differences in soil microbial community structure is demonstrable in orchard soils 20 years after receiving a single application of sewage sludge (within EPA guidelines) (Kelly et al., 1999a). Additionally, little is known about phytotoxicity or accumulation of elements such as molybdenum into several crops crucial to Northeastern agricultural (e.g., forage crops like alfalfa, grains, and vegetables) which are much more sensitive to metals than the well studied crops like corn. The potential for excessive molybdenum to cause harm to ruminant animals such as dairy cows and the prevalence of leguminous forage in the Northeast make research on molybdenum in the Northeast a pressing need.



The report titled Criteria and Recommendations for Land Applications and Sludges in the Northeast (Baker et al., 1985) addressed many of these concerns. However, many of the recommendations of the report (both explicit specific metal loading rates and implicit considerations of soil texture in standards development) were not reflected in current regulations. Examination of long-term sites in sensitive regions, such as the Northeastern U.S., with substantial metal accumulation from sludge applications is needed to develop an improved assessment of the sustainability of long-term applications of the sewage biosolids.

Accurate knowledge of the quality of sewage biosolids and of soils and plants from biosolids-amended sites is critical. Uncertainty due to different analytic methods needs to be reduced in order to make results between studies comparable. Fluctuations over time in the quality of sewage biosolids from a single STP are significant. Growers and their advisors need information on this variability in order to make appropriate decisions regarding application rates.



Nonylphenols

The degradation of common nonionic surfactants such as nonylphenol polyethoxylates in STPs leads to the accumulation of estrogenic nonylphenols in anaerobically digested sludge at levels as high as 4000mg/kg (Bennie, 1999). Although nonylphenol-based surfactants have been phased out in Europe they are still widely used in the United States, where there is neither monitoring nor regulation of nonylphenol concentrations in sewage biosolids. Because application of nonylphenol-contaminated sludges is a possible source of ground and surface water contamination, more work is needed to understand the fate of these compounds in agricultural settings.



Groundwater As cited below, ongoing research at Cornell University has found rates of metal movement higher than typically assumed. Preferential flow and facilitated transport mechanisms are not well understood and may be significant for trace element, pathogen and toxic organic transport, particularly under Northeastern conditions. Additionally, the effects of total ecosystem interactions or feedback (i.e. metals in sludge to soil to feed crops to manure to soil; or soil to groundwater to manure to soil loops) on long-term accumulations or mobility need to be evaluated.

An incomplete understanding of trace metal behavior in a farm system may compromise the long-term viability of farms, impact their immediate environment, and complicate legal liabilities (Goldfarb et al., 1999). In view of the unresolved questions concerning sludge-borne metals, it is evident that there is a necessity to document the long-term total ecosystem mobility and fate of sludge-borne contaminants in the more sensitive soil and water systems typical of the Northeastern U.S.



Nutrients Nutrient balance studies of farm systems in the Northeastern U.S., especially dairy farms, show a large net importation of N, P, and K (Klausner, 1993; Bacon et al., 1990; Dou et al., 1995; Hutson et al., 1998). The use of sewage biosolids is a source of imported N and P. The excess nutrients either accumulate in the system (i.e., increased soil nutrient contents) or are lost to the environment (denitrification, overland flow or tile drainage to surface waters, and leaching to groundwater). Nitrogen mineralization rates are variable (Douglas and Magdoff, 1991). Little work has been done on mineralization rates from sewage biosolids. If the rate is overestimated, crops will suffer from N limitation. Conversely, underestimation of mineralization results in over-application, excess N availability and increased risk of nitrate leaching. In cases where alkaline-stabilized sewage biosolids are used as a lime substitute, the accompanying N and P contents are often not matched by corresponding reductions in fertilizer applications. The temporal variability in nutrient content of sewage biosolids generated even at a single treatment plant makes it difficult to predict appropriate agronomic application rates. Finally, the wide P:N ratio of wastewater sludges (greater than that of manures) means that the overloading of P typical of many farms in the Northeast is exacerbated by the use of sludges in contrast to manures (Klausner et al., 1998). Improved understanding of variability in nutrient content and N mineralization rates of sewage biosolids and of the relationship of wastewater treatment processes to the content and availability of nutrients is needed.



Pathogens Sewage biosolids contain a variety of pathogens, including bacteria, viruses, protozoa, and parasites. Treatment processes reduce the number of such organisms, but do not eliminate them (Goddard et al., 1981; Payment et al., 1982; De Maturnana et al., 1992; Mayer and Palmer, 1996). For sewage biosolid products to be land-applied, they must at least meet Class B standards, indicating that they have been treated with a 'Process to Significantly Reduce Pathogens'(PSRP), such as anaerobic digestion. Many sludge products (i.e., composted, pelletized, or alkaline-stabilized) are further treated by a 'Process to Further Reduce pathogen' (PFRP) so that they meet 'Class A' standards, and have no pathogen-related restrictions on use.



Land application of Class B sludges requires certain management restrictions on use for human food and time delays before animal grazing or human site access is allowed, because viable pathogens may still be present in substantial numbers. The regulations for Class B sludge application are based in part on the assumption that soil is a hostile environment for the pathogens and their populations will quickly be reduced to acceptable levels. However, there is potential for transport of pathogenic organisms through overland flow (Dunigan and Dick, 1980) and leaching (via preferential flow paths) that is not typically addressed in regulations or management recommendations.



Social, Political and Legal Impacts

In the Northeast, with the close proximity of residences to farms and the relative abundance of sewage biosolids from nearby urban centers, land application of biosolids is especially controversial. Social science research indicates that risk perception plays a major role in whether citizens accept hazardous activities, substances and technologies (Juanillo and Scherer, 1995). Without understanding what people think about and how people respond to risk, well-intended policies may be ineffective (Slovic, 1987). The decisions of farmers to land-apply sewage biosolids are not only dependent on scientific issues concerning human and environmental health, but also on how they and their neighbors and local officials perceive potential risks (NRC, 1996).



These risk perception and communication issues involve interactions between various constituent groups, who can be seen as stakeholders; farmers, growers, or other potential appliers; scientists; sludge producers; site neighbors; the public; governments; and the media. Little information about risk perception or case studies about sludge land application could be found in a preliminary literature search. Since this issue is so controversial in the Northeast, research on the perceptions of growers and case studies of land application are needed. In response to local concerns regarding land application of sludges, particularly those sludges originating in a different municipality, a number of municipalities have adopted local ordinances (Goldfarb et al., 1999). These ordinances range from very simple bans to complex laws addressing many specific issues (Harrison and Eaton, in press). Some localities seek to base their laws on scientific data relevant to their community and seek guidance from the land-grant university and cooperative extension. The adoption of local laws can complicate land application programs since requirements may be different from locale to locale.



NEED FOR COOPERATIVE WORK



During the Northeast Regional Agronomy Meeting at Cornell University in July 1996, a session was convened to discuss the issue of application of sewage sludges to agricultural lands. Those in attendance represented NY, NJ, MA, ME, DE, and Canada. To further identify opportunities for collaboration, other state experts were subsequently contacted. From these interactions, a need for cooperative studies to develop appropriate guidance, such as updating the 1985 Criteria (Baker et al., 1985) was identified. Subsequently, under the auspices of NEC-100, these and other interested individuals met in December 1997 and 1998, July 1999 and January 2000 to exchange research results and to investigate common interests and projects. Based on these meetings and on the foregoing analysis of the complexities of impact of sewage biosolid-based materials on Northeastern soils in general, and agricultural systems specifically, it is concluded that further collaborative exploration of the issues is needed. Participation in a cooperative research project, and development of appropriate soil/sludge management practices for regional conditions is essential to provide for the use of sludge materials while insuring the long-term sustainability and optimal quality of the area agricultural soils and systems.



RELATIONSHIP TO CURRENT PRIORITIES



This proposal will primarily address CSREES National Goal 4: Greater harmony between agriculture and the environment. Through this research we will assess the potential impacts to ground and surface waters and to soil quality associated with application of sewage sludges under conditions typical of the Northeastern U.S. In addition, several of the research needs identified in the 1994 ESCOP publication, "Opportunities to Meet Changing Needs" will also be addressed. In particular this multidisciplinary project deals with the following areas identified in ESCOP priorities: 1) Recovery and Use of Waste Resources and 2) Synergy at the Agricultural - Urban Interface.

Related, Current and Previous Work

A closely related effort is the W-170 Regional Research Project, 'Chemistry and Bioavailability of Waste Constituents in Soils.' The objectives for that project are:

1. Characterize the chemical and physical properties of residuals and residual-amended soils;
   
   
2. Evaluate methods for determining the bioavailability of nutrients, trace elements, and organic constituents in residuals; and
3. Predict the long-term bioavailability of nutrients, trace elements, and organic constituents in residual-amended soils.
   
   

This proposed project will complement the W-170 project in several ways. The most important contribution of this proposed project is the focus on the soils, crops, and animal combination typical of, and unique to, the Northeast. The proposed effort to characterize the variability of biosolids (Objective 2), the analysis of pathogen movement to groundwater, the investigation of nonylphenols and the interface between the scientific and social components are other unique contributions of this proposal.



Studies evaluating short-term effects (i.e., 5 years or less) of sludge application abound. These studies have provided an excellent foundation of some of the principles governing soil-sludge systems and the resulting environmental impacts. However, as stated above, some of the more specific data needs relating to sludge application to the more shallow, acidic soils typical of the Northeastern U.S. and the implications for closely associated urban and agricultural communities are missing. Thus, this summary is restricted to projects that suggest the need for a closer examination of land application under conditions of Northeastern U.S. A search of the CRIS system (August 31, 1999) for related projects (search words, "sewage sludge" and "soil") revealed a total of 51 projects. The majority of these involved evaluation of the nuances of the nutrient-supplying capability of sludge materials, were short-term studies of environmental aspects, or involved soil systems disparate from those of interest in the context of this project. These studies are generally of relatively short duration, and are focused on effects assessed in greenhouse, soil column studies, or small field plots.



Variability

To determine appropriate application rates of sewage biosolids and to ensure low pollutant levels, knowing the chemical composition of sewage biosolids is very important. The chemical composition of sewage sludge is affected by the wastewater influent (e.g., local and regional differences, industrial input, seasonality of industries, street runoff) and the treatment process (e.g., lime additions, dewatering, digestion).



Studies in the 1970s showed that sewage sludge composition varied greatly among facilities and also over time within the same facility (Page, 1974; Sommers et al., 1976; Doty et al., 1977). Almost every parameter varied widely (Doty et al., 1977). The concentration of water-soluble constituents (i.e., NH4+-N, NO3--N, K+) was especially affected by the dewatering process in comparison to constituents that are associated with the solid fraction (e.g., P and metals) (Sommers, 1977). Since the NH4+ concentration in liquid sewage sludge is generally in the 200-500 mg/L range, the expression of NH4+-N on a dry basis will partly be responsible for the variability of NH4+-N (Sommers et al., 1976). This was also observed for other water-soluble constituents. These earlier studies collected more data about the variability between facilities than the variability in the same facility and focused on aerobically and anaerobically digested sewage sludge, the major sewage sludge types at that time.



Peer-reviewed articles about sewage sludge variability within the same facility are about 20 years old. During the last 20 years, pollutant concentrations, sewage sludge treatment processes and analytical sensitivity have all changed. Over the last 20 years, there has been a decrease in the concentration of a number of pollutants due to changes in industrial operations and pre-treatment of industrial wastewater (Gschwind et al., 1992; NJ DEP, 1999; Stehouwer and Wolf, 1999). Synthetic organics were not evaluated in these earlier studies. However, various contemporary data about sewage biosolids composition are available (e.g., monitoring data required by state and federal regulations, data from sewage sludges used in specific experiments). A current reevaluation of variability between STPs, taking into account the differences in sampling locations within various facilities and the variability in sampling procedures and analytical methods, is needed. In addition, examination of the fluctuations between sampling events within a single STP is needed.



Groundwater

Some current research suggests that the mobility of sludge-applied metals may be substantially higher than has been previously assumed. Many field studies that conducted post-application mass balances failed to detect a large fraction (often as much as 50%) of sludge-applied metals (e.g., Alloway and Jackson, 1991; Dowdy et al., 1991; Chang et al, 1984; Williams et al., 1987). Researchers have typically concluded that leaching was not the reason for this apparent loss of metals. Their conclusion was based on the observations that: (a) no increases in metal concentrations were detectable at depth in the soil profile (e.g., Dowdy et al., 1991; Chang et al., 1984) and/or (b) metals are not mobile in conventional soil column experiments (e.g., Emmerich et al., 1982). However, their alternative explanations of the apparent metal loss, including lateral distribution by tillage (e.g., McGrath and Lane, 1989; Williams et al., 1987), or metal reversion to mineral forms not detectable by strong acid digestion (e.g., Dowdy et al., 199l; Chang et al., 1984), appear to be inadequate.



Studies at Cornell have, in contrast, directly observed downward mobility of heavy metals in both field and controlled soil column studies with undisturbed soils treated in a manner to preserve preferential flow paths. It was shown that metals applied in inorganic salt solutions can rapidly pass through undisturbed soil profiles, but were immobilized by conventional packed laboratory soil columns (Camobreco et al., 1996). In the Camobreco et al. (1996) study (a breakthrough-curve study), metals with low organic affinities (Cd, Zn) moved rapidly through the undisturbed columns, whereas metals with high organic affinity (Cu, Pb) were slowed, but not immobilized. When metals were applied in an organic solution (with sufficient capacity to complex all heavy metals in soluble and/or mobility colloidal forms), all metals moved through the undisturbed soil profile with similar rapidity. It appeared that the presence of preferential flow paths and the presence of transportable (soluble and/or colloidal) organic matter both facilitate the transport of the metals.



Similarly, movement of metals has also been observed in an old field site (Richards et al., 1998), where lysimeters installed under undisturbed profiles have measured ongoing metal fluxes (0.5 to 2 kg ha-1 yr-1) for Cu, Zn, and Ni nearly 20 years after a single heavy sludge application. Soil analysis of the site by McBride et al. (1997) indicated substantial losses of metals from the topsoil. Interestingly, examination of the soil profile showed no evidence of metals enhancement at depths up to 2 m, even along preferential flow paths (Richards et al., 1998). The lack of metal deposition at depth therefore appears to be unreliable presumptive evidence for lack of metal mobility. The conventional 'no enhancement at depth' argument for metal immobility is predicated on two assumptions: (a) transport governed by the convective-dispersive model and (b) a reactive solute, easily reabsorbed at depth. In contrast, transport actually appears to be governed by (a) fast and far-reaching preferential flow, and (b) transport in relatively non-reactive forms (i.e., as soluble and/or colloidal complexes). Similar observations were made in France where Cd and organic substances increased in tile outflow (at a depth of 1m) immediately after application of digested sludge (Lamy et al., 1993). A parallel can be drawn to recent discoveries of rapid preferential flow of pesticides, once thought to be largely immobile (Kladivcko et al., 1991; Milburn et al., 1995; Steenhuis et al., 1990).



Mode of sludge processing can also substantially enhance the mobility of metals in various sludge products derived from an identical dewatered sludge feedstock (Richards et al., 1997). One common process results in TCLP mobile fractions of 25 to 50% for Mo, Cu, and Ni. Processing also affected percolate concentrations when these sludge products were applied to undisturbed soil columns in a long-term greenhouse experiment (Richards et al., 2000).



Preferential flow processes have also been shown to facilitate the rapid transport of pathogens or indicator organisms from applications of manure (e.g., McLellan et al., 1993; Evans and Owens, 1972; Dean and Foran, 1992). After sewage sludge is applied to land, some of the pathogens, such as viruses, have been shown to travel through the soil column and contaminate underlying groundwater (Powelson et al., 1991). Bacteria and protozoa are typically retained in the soil and do not travel to great depths (Edmonds, 1976). However, they may remain viable in the top few centimeters of the soil column and subsequently runoff or leach into ground or surface waters.

Colloids have been shown to play a significant role in the movement of trace elements in conjunction with preferential flow. In most current models, the role of colloidal transport is not, however, adequately taken into account. A recent evaluation (Norris and Hubbard, 1999) of the MINTEQA2 model used by USEPA for assessing transport from land-disposed wastes found multiple instances where inaccurate assumptions regarding colloidal transport significantly underestimated predictions of potential metal transport.



Molybdenum

A greenhouse study of Mo uptake into red clover from sludge-amended soils, as well as a field investigation of the uptake of Mo into corn and soybeans at the Cornell orchard site where a low-Mo sludge had been heavily applied 20 years earlier, have been completed. The studies revealed a high residual availability of Mo to legumes in particular, even though total Mo concentrations in the contaminated soils did not exceed 3 mg/kg (McBride, 2000). A survey of forage composition on dairy farms in New York that have applied sewage biosolids, conducted in 1999 by Cornell researchers J. Cherney and M. McBride, has determined that alfalfa and clover forage on some farms applying sewage biosolids have Mo concentrations in the potentially hazardous range of 5-15 mg/kg. Subsequent sampling of the affected farm fields is underway to determine the variability of Mo in forages depending on growing conditions and time of year. Present studies are underway to evaluate a modified "hot-water" soil extraction test for its ability to predict uptake of Mo into red clover in the greenhouse, as well as the concentrations of Mo found in forages collected from dairy farms using sewage biosolids. Soils collected on New York farms in conjunction with the 1999 forage survey will be subjected to the "hot water" soil test, and the Mo extracted by this test will be correlated to the forage Mo concentration. It is hoped that this simple test estimates bioavailability of Mo with sufficient accuracy to be able to determine which soils may not be suitable for growing forage legumes. Further examination of long-term availability of sludge-applied Mo to forage legumes is being investigated by M. McBride and B. Hale at the University of Guelph. Alfalfa will be planted in spring 2000 on sludge plots representing two soil types (sandy and silt loam soils), three sludge types, and four sludge application rates. The alfalfa will be harvested and analyzed for Mo and other trace elements. Since the sludges were last applied on these plots in 1979-80, this experiment is only a test of residual effects decades following sludge application.



Pathogens

Over the last several years the laboratory of A. Margolin at the University of New Hampshire has been developing and investigating more sensitive ways for the detection of enteric viruses in sewage biosolids. Current methodology requires the use of a plaque assay that is often done using the BGM cell line. This assay and cell line has been shown to work effectively only with certain enteroviruses, such as poliovirus, coxsackie virus, and echoviruses. Using this type of assay does not permit detection of other medically important viruses such as rotavirus, astrovirus, hepatitis A virus, or adenovirus. Many of these viruses occur in much higher concentrations in sludge than the enteroviruses mentioned above. Additionally, utilization of a plaque assay is very time consuming, requiring up to several weeks for confirmed results. Many viruses will not form plaques, especially after treatment.



Margolin's lab has developed an assay, which is very sensitive for the detection of viruses. In this assay, an integrated cell culture nested reverse transcription polymerase chain reaction (ICC-nested-RT-PCR) is used for the ultra-sensitive detection of 6 different enteric viruses (poliovirus, coxsackie virus, echovirus, astrovirus, rotavirus and adenovirus). The assay can be used as a screen for the presence of virus or as a means for determining infectious virus. It is a rapid assay, providing results in 72 hrs. This assay has been used for evaluating sewage biosolids intended for land application (Chapron and Margolin, 2000).



Nonylphenols

Although recent evidence suggests that nonylphenols spiked into uncontaminated sludge are degraded over several months, a significant portion of the nonylphenols in aged sludges is recalcitrant to biological transformation (Topp, 2000). In addition to persistence in the soil, the sorption of nonylphenols onto organic matter may give rise to the facilitated transport of these compounds into groundwater. Nelson et al., (Nelson et. al., 1998) have shown that hydrophobic chemicals may complex with dissolved organics and be rapidly transported through the soil profile. This is a concern as complexation of hydrophobic chemicals with organic matter can inhibit the ability of microorganisms to degrade these compounds even though they may still be available and therefore toxic to higher organisms (Rinella, 1993).



A preliminary analysis by A. Hay at Cornell shows nonylphenols to be present at concentrations of more than 1000 mg/kg in sewage biosolids from two upstate NY STPs receiving predominantly residential wastewater. These values can be compared to the temporary permissible limit of 50 mg/kg nonylphenol allowed in land-applied sewage sludges in Denmark (Cavalli, 1999). One of these sludges is being land applied.



Nutrients

Many investigators have reported crop yield increases following the applications of sewage sludge to farmland (Sims and Boswell, 1980; Stark and Clapp, 1980). These responses result from improvements in soil physical and chemical properties (Epstein et al., 1976, 1978). The chemical improvements are reported to be due in part to increases in soil N imparted by sludge applications. Yields of corn (Zea mays L.) fertilized with sewage sludge were equivalent to those obtained with ammonium nitrate or urea (Sims and Boswell, 1980). Mineralization of N from sewage sludge has been studied extensively with results showing that mineralization is highly variable but suggesting that up to 50% of fresh sludge N was mineralized in the year of sludge application (Magdoff and Amadon, 1980; Premi and Cornfield, 1971; Stark and Clapp, 1980). Residual N continues to mineralize following the first season but slower rates (Pratt et al., 1973). There is a potential for nitrate pollution from excessive initial application, mineralization of the residual organic N, and subsequent fresh applications (Magdoff and Amadon, 1980; Sims and Boswell, 1980; Stark and Clapp, 1980). Loading rates of N from sewage biosolids are generally used as the factor to limit the amount of sludge that can be applied. Uncertainty regarding the amount of available N in a sludge due to fluctuations in N concentrations and sludge moisture content as well as uncertain mineralization rates makes determination of agronomic rate application problematic. A five-fold variation in agronomic application rates over a 9-month period was calculated for land-applied sewage biosolids from one upstate NY STP (Harrison, 2000).



Phosphorus in sewage sludge is in organic combination and hence must be mineralized before it is released for plant nutrition (Frossard et al., 1996; Hinedi et al., 1989) and its availability relates to processes within the STP. Additions of sludges to soils increases soil-available P (Frossard et al., 1996; Kirkham, 1982) which is an increasing water quality concern. Application of sewage biosolids based on crop N needs, may result in excessive application of P. Further information on how sludge-borne P relates to STP processes and on P availability is needed.



Soil system quality and sustainability

Maintenance of an active, diverse soil microbial community is essential for long-term stability and sustainability of all soil ecosystems, but it is especially critical for intensively cultivated soils. Organic matter amendments are generally found to have positive benefits on soil productivity and structure, but the trace metal contents of biosolids may also have a negative impact on system stability and product quality. Soil enzymatic activities and deviations in indicator microbial populations have been used to evaluate implications of soil amendments and management decisions on soil function (See Tate, 2000 for a review of this topic), but frequently the data are equivocal. Metabolic diversity analysis (BIOLOG) and phospholipid fatty acid analysis (PLFA) have recently proven to be good indictors of soil population variability in general soil systems (e.g., Garland, 1996; Garland and Mills, 1991; Kennedy and Smith, 1995; Zak et al., 1994) and in metal contaminated soils (e.g., Frostegard et al., 1996; Giller et al., 1998; Kelly and Tate, 1998a, 1998b; Kelly et al., 1999b; Knight et al., 1997), including biosolids amended soils (Kelly et al., 1999a). These procedures are useful for indicating changes in general populations (such as deviation in fungal populations in the presence of metals) as well as overall population shifts due to low and high metal loading.

Objectives

1. To evaluate the utilization of sewage biosolids in soil management in the Northeast by assessing the sustainability of soil quality, water quality and food safety (for people and other animals) where sewage biosolids are applied to agricultural land.
   
2. To evaluate the legal, social, and political aspects of long-term utilization of sewage sludge products in the Northeast and to identify modes of stakeholder participation in biosolids utilization decision-making.
   
3. To develop appropriate outreach materials and educational events for the Northeast that links the current research to actual field management of sewage biosolids products in the Northeast
   
4. 
   

Methods

The collaborators are leaders in soil science, engineering, water resources, social science and other aspects of relevant research. They bring complementary expertise to the project and by working together will provide for a much more comprehensive research program and assessment of impacts than would be possible through separate and independent projects. Addressing the complexity of the issues requires this diversity of experts.

One aspect of this multi-state project is to modify the research design of the separate projects which individual members are engaged in to develop a new and consistent set of data. By applying procedures consistently among the various active research projects, the opportunity to gain tremendous insights across the region exists if this project is implemented. The limited funding available for multi-state projects makes it particularly valuable that the research in which collaborators are already independently involved can contribute to the success of this project. Development of consistent site and sewage biosolids characterizations and sharing of samples to both ensure consistency in analytic results and to develop a more comprehensive and consistent array of analytic parameters is one important project outcome. Collaboration on the specific field sites will bring a wider array of expertise to bear than otherwise possible.

The collaborators are representative of the states in the Northeastern region of the U.S. and the adjacent regions of Canada. Current and proposed research sites are characteristic of soils and conditions of the region. As stated above, the Northeastern U.S. has particular soil, climate and agricultural conditions that make it critical to evaluate sludge application as it pertains in this region. Much of the data used to develop current rules and guidelines derive from other areas of the country with very different conditions. This multi-state project presents the opportunity to work jointly across disciplines and states to answer key questions as they relate to conditions in the Northeast.

Objective 1. To evaluate the utilization of sewage biosolids in a soil management scheme for the Northeast by assessing the sustainability of soil quality, water quality (surface, ground and drinking water) and food safety (for people and other animals) where sewage biosolids are applied to agricultural land.

A good understanding of the sources of uncertainty about the composition of sewage biosolids plays a role in assessing risks and benefits associated with land application. The committee has identified two key areas of uncertainty that need to be addressed in order to make sound management recommendations. Task 1 addresses analytical variability, which can be significant whenever trace levels of contaminants are being analyzed in a difficult, complex matrix. Task 2 examines temporal variability in sewage biosolids composition, which has implications for sampling and analysis frequency, for application rate recommendations (when rates are predicated on nutrient concentrations), and for risk of non-compliant "hot" loads. Tasks 3 and 4 relate to assessing transport and fate of contaminants. These tasks will involve cooperative research on experimental systems and at field sites in the Northeast. Task 3 focuses on the survival and transport of pathogens present in sewage biosolids. Task 4 assesses the long-term fate of trace elements and other trace toxics and their impact on soils.

Task 1. Analytical variability

Procedures: To assess inter-laboratory data variability and accuracy, the committee will use a common set of about 30 to 50 soil samples, 30 to 50 plant samples, and 30 to 50 water samples contributed from a common source and previously analyzed to detect an array of concentrations of the elements. The specific methodology to be applied will be designated by the committee after the preliminary work on the initial 30 to 50 samples of each material. For example, for soils, analysis of total elements will employ extraction of the soils with aqua regia. For analysis of extractable elements, the extractants will include dilute calcium chloride solution, hot water, Morgan's solution and Melich 3 solution. Instrumentation will include determination of the elements by ICP emission spectroscopy, axial view ICP spectroscopy, and ICP-MS spectroscopy. The elements of interest include Zn, Cu, Mn, Mo, Cd, Ni, Pb, and Cr.

• Plants: The committee will analyze plants for total elements by an acceptable procedure that will involve wet or dry ashing. Instrumentation will be by the same procedures listed above for soils.
  
• Water: The committee will prepare water for total dissolved elements by an acceptable procedure that is common among the investigators. The procedure will be used to compare runoff impacts from manure/fertilizer, sludge applications at the Bath site, New York.

Participants: Guelph, MA, NH, NY, PA

Task 2. Evaluate the temporal variability of the chemical composition of sewage biosolids

Sewage sludge monitoring data obtained from various state agencies (e.g., New Jersey, New York) will be analyzed for selected characteristics over time for specific wastewater treatment facilities. Focus will be on facilities that land apply their sewage biosolids. Stratification variables will include facility size and portion of industrial input. The influence of sampling, analytical methods used and comparability between laboratories will be identified. Fluctuations in key parameters such as nitrogen at individual STPs will be assessed.

The composition of sewage biosolids from an array of STP which land apply their sludges will be analyzed for nonylphenol polyethoxylates. Where data are available, other organic contaminants such as dioxins and PCBs will be included.
Variability in the levels of P both between different STPs and within a single STP will be examined and the relationship to STP processes investigated.

Participants: NJ, NY, and PA

Task 3. Assess pathogen survival and transport

Class B sewage biosolids at selected long term application sites and groundwater samples from sites where sewage biosolids have been applied will be tested for the presence of viruses using new sensitive methods.

Participants: NH collaborating with NY

Task 4. Assess the long-term fate of trace elements and nonylphenols present in sewage biosolids, and factors contributing to transport and to evaluate the impact of sewage biosolids on sustainability of field soils. This task also incorporates standards for site characterization and data collection to enhance comparability.

Two types of experiments will be carried out to determine the transport and fate of pathogens, metals and nonylphenols from short- and long-term application of biosolids. Laboratory experiments with undisturbed soil cores allow relatively rapid testing of a range of factors (soil types, biosolids types and loading rates, leaching intensity) in a controlled, replicated environment. Undisturbed soil cores have been shown to provide a reasonable representation of field phenomena (Richards et al., 2000). Instrumented sludge application field sites will also be operated because they are the most realistic (but, conversely, least controlled) experimental systems. We envision bringing the multiple areas of expertise to bear on sites, such as happened with the sampling of a Cornell field site (Richards et al., 1998) by Rutgers researchers developing tests for long-term microbial community shifts (Kelly et al., 1999a). To evaluate the shifts in microbial community populations and activity, metabolic diversity, PLFA, microbial biomass, and dehydrogenase activity will be assessed. Cooperative research will be facilitated if comparable experimental procedures and sampling devices are used.

Undisturbed soil cores

Laboratory-scale columns extracted from selected field sites will be used to study colloid transport in detail. Undisturbed cores from different soils and regions will be taken (Richards et al., 2000). Trace elements and factors facilitating transport (soluble/colloidal organic carbon as well as other colloids) in the outflow water will be determined, as will crop uptake and response, where possible.

Field experiments

We envision several field sites being examined throughout the northeast. An example is an ongoing study at the Dickson Farm (Bath, NY) where manure and sewage biosolids has been land applied on designated fields since 1978. Sampled fields represent treatments of manure, sludge, fertilizers, and a forested control plot with no human activities. Sites in other states should be representative for the major soil types. A number of water sampling devices are available for monitoring transport in soil water, runoff and interflow, including wick and gravity pan lysimeters, ceramic suction cup samplers, piezometers, tile lines and vertical wells. Wick and gravity pan lysimeters show particular promise for assessing trace element mobility (Steenhuis et al., 1989; Richards et al., 1998). Samplers will be used to monitor the transport of pathogens, nitrate, phosphorus, nonylphenols, metals and other elements. Soil samples to a depth of 1 meter will be taken, analyzed and correlated with the percolate concentrations. A nonreactive tracer (bromide or chloride) at low concentration can be applied once and monitored to deduce preferential flow paths in the soil.

Soil properties are highly variable in the region. This variability is further enhanced by management history and site characteristics. To be able to adequately account for variation in results between experimental sites, a complete description of the site descriptive parameters is essential. The committee proposes that the following information should be collected on each site:

Site description

• Topography (including source of data), GPS coordinates
  
• Physical description of site: slope, slope length and aspect, physical relationship of soil management units with relationship to sampling sites.
  
• Drainage characteristics (soil depth, conductivity class, depth to water table, presence of tile and/or surface drainage)
  

Soil information

• Soil survey mapping unit (with on-site confirmation of the soil survey where possible)
  
• Soil profile information: representative pit description, texture analysis.
  
• Soil analyses: CEC, pH, TOC, Ca+Mg+K+P, TKN, nitrate, exchangeable ammonium, trace elements
  
• Farmer and/or applier soil testing information history
  

Management/application practices

• Management history: tillage practices, crops, fertilizers, lime, etc.
  
• Amounts and dates of application (both sewage biosolids and manures)
  
• Analytical information on sewage biosolids applied
  

Other information that would also be useful for inclusion in the
database includes:

• Aggregate stability
  
• Bulk Density
  
• Coarse fragment content
  
• Parent material, mineralogy,
  
• Saturated hydraulic conductivity (in field)
  
• Specific organics in soil and/or sewage biosolids: surfactants, pesticides, furans, PCBs
  
• Pesticide history (especially for old orchards)
  
• Location in relation to drinking water wells, other residential inputs (septic tanks), proximity to critical source areas (ground water recharge areas and surface runoff)
  
• Status of neighbor and legal concerns
  

Participants: MA, NH, NJ, and NY

Objective 2: To evaluate the legal, social, and political aspects of long-term utilization of sewage sludge products in the Northeast and to identify modes of stakeholder participation in biosolids utilization decision-making.

Tasks 1-5 move from qualitative hypothesis-generating tasks to quantitative, hypothesis testing tasks.

Task 1: Explore vegetable growers' understandings of the risks and benefits of land application as well as their perceptions of public response to land application of biosolids.

Understanding growers' perceptions and choices regarding land application of biosolids is key to developing locally accepted strategies for managing biosolids. Qualitative research with vegetable growers will be conducted about perceptions of benefits, risks and use of biosolids. This information will also help in developing criteria for selecting case studies.

Participants: NJ, NY

Task 2: Develop case studies on land application of biosolids to crops in the Northeast.

Cases with differing histories will be compared, such as a grower that used biosolids and had little community resistance which a grower who applied biosolids and encountered substantial resistance, such as neighbor complaints and restrictive municipal ordinances. Criteria for choosing cases will focus on contrasting legal and institutional structures and processes for managing land application of biosolids, such as diverse statutory, administrative and judicial approaches and outcomes.

Qualitative research with key stakeholders in each case study will be conducted. These case studies will provide data on the experiences of growers who have applied biosolids in the Northeast, and also in the various legal and institutional approaches to land application of biosolids.

Participants: NJ, NY

Task 3: Assess public reaction to sludge application scenarios.

Using methods developed for assessing attitudinal response to narrative presentation of risk issues (Shanahan, et al., 1999) we will conduct pilot surveys of Northeastern residents about reactions to different ways sludge application could be presented. Respondents will be asked to consider a hypothetical case in which sludge application is being considered in a town similar to their own. Posing the interests of different stakeholders against each other, the survey will ask respondents to assess different outcomes in terms of favorability to their own preferences and interests. The results will show how perceptions influence acceptability of scientific results, and will begin to show how different stakes can be expected to act in a context of political and scientific uncertainty. The survey will address attitudes relating to both the environmental and food safety issues germane to land application.

Task 4: To develop a mechanism to evaluate the legal, social, and political impacts and issues associated with land application of sewage biosolids products.

A variety of questions from an array of stakeholders are posed to extension agents and others regarding the safety, social, and political issues associated with land application of sewage biosolids. The implications are not always obvious and, in reality, adequate answers are often not currently available. Data collected under Objective 1 tasks will be useful in determining the actual risk of the land recycling procedure for these waste materials. Additional social and political information is required to provide responses to questions regarding "perceived risk" and their legal and political implications. Data will be collected through various avenues including media searches on the WWW, searches of legal cases, contacting state and local governments and their associations, and by asking questions of extension agents in counties where agricultural land is being used for sewage biosolids recycling. Question include:

• Are there lawsuits in this region relating to biosolids application?
  
• Have there been any enforcement actions or hearings?
  
• Has there been significant controversy or complaints?
  
• Has there been any newspaper coverage?
  
• Are there any local ordinances proposed, passed or defeated?
  
• Are there any local politicians who addressed this issue?
  
• What are the economic arrangements surrounding land application at the site?
  
• Does the grower pay or is income provided to the grower for the application?
  
• Are there payments to the municipality or neighbors for things like enforcement or road maintenance?
  

These data will be useful for regulators as well as extension agents, local governing bodies, individual growers, and STPs. The data will be collected and posted on a secure web site for project participants. As a representative data set from the region, supplemented by relevant observations from outside the region, specialists in communications, risk assessment, and policy will develop it into materials of use for the various stakeholders.

Participants: NJ, NY

Objective 3: To develop appropriate outreach materials and educational events that links the current research to actual field management of sewage biosolids products in the Northeast.

Task 1 will enable project participants to share information efficiently internally and externally. Task 2 addresses the opportunity to cooperate in extension efforts among the participating states.

Task 1: To develop a web site for exchange of information, experiences, and data between project cooperators and with the public (support for objectives 1, 2, and 3).

Traditionally in multi-state committees, data, reports, and publications have been shared at annual meetings. It is a goal of the committee to establish a secure central web site accessible to project participants with links to individual web sites of the committee members. Project results, abstracts of publications, and other general research ideas will be posted on the site. It is anticipated that the "editorial policy" of the site and management matters will be established during the first year of the project and that the site will be "up and working" during the second year of the project. This site will facilitate data sharing and inter-laboratory communication and cooperation. A second phase of this portion of the project will be development of a similar site for the general public where project accomplishments, publications (abstracts of journal papers, and extension publications), and committee recommendations can be posted.

Participants: all

Task 2: Compile, compare and develop Extension materials.
Extension materials relating to land application of sewage biosolids from each of the participating states will be collected and compared. Opportunities to share publications and programs will be explored. Opportunities to incorporate new research resulting from this project and related research will be identified and new materials may be developed.

Participants: all

Measurement of Progress and Results

Outputs

• Peer-reviewed publications on analytical methods plus an extension-type report
• A research-driven web site for exchange of ideas and data between project participants
• General recommendations for experimental data collection and a data base that will be a resource for evaluating future concerns with land disposal of sewage sludge
• Improved best management practice recommendations and a web site for their dissemination to stakeholders.

Outcomes or Projected Impacts

• Reduced risk through improved best management practices and regulations for soil, water, and societal consequences of soil applications of sewage biosolids to thin, acidic soils characteristic of the Northeastern, U.S.

Milestones

(2001):Agreement reached on standardization protocols. Web site initiated. Temporal variability data collected. Pathogen survival measurement and transport monitoring initiated. The long-term fate study of trace elements initiated.

(2002):Web site completed. Standardization protocols tested and adopted. Plant analyses completed (wet and dry ash). Water analysis study completed. Waste treatment plant site-descriptions completed . Soil information/data gathered . Management practices recorded.

(2003):Survey data on legal, social, and political aspects collected (both interviews and case studies) . Public reaction to sledge assessed by survey. Plant and water data analyzed.

(2004):Remaining data analyzed. Analysis of qualitative survey data completed . Web site augmented with research results. Appropriate outreach materials developed.

(2005):Extension materials completed and shared . Web site for exchange of information, experiences, and data between project cooperators and with the public completed . Research publications completed . Planning for any needed follow-up research initiated.

(0):0

Projected Participation

View Appendix E: Participation

Outreach Plan

Integrated into project. See Objective 3/and corresponding Tasks 1 and 2.

Organization/Governance

The committee will consist of participating researchers from the contributing states, the administrative advisor, and CSREES representatives, plus representation from W-170 and US EPA. Voting membership includes one vote from participating research institutions, but participation of all engaged researchers and advisors is encouraged. The committee will elect two co-chairs and secretary annually. The committee or the co-chairs may establish subcommittees as necessary to accomplish specific goals. The administrative advisor notifies committee members of the time and place of meetings. The chairs prepare and distribute the agenda, preside at meetings, prepare the annual report with input from the committee and provide project coordination. Meeting locations and arrangements will rotate among members.

Literature Cited

Journal

Elliott, H.A., G.A. OConnor, and S. Brinton. 2002. Phosphorus Leaching from Biosolids-Amended Sandy Soils. J. Environ. Qual. 31:681-689.

Elliott, H.A., G.A. OConnor, P. Lu and S. Brinton. 2002. Influence of Water Treatment Residuals on Phosphorus Solubility and Leaching. J. Environ. Qual. 31: 1362-1369.

OConnor, G.A., H.A. Elliott, and P. Lu. 2002. Characterizing Water Treatment Residuals Phosphorus Retention. Soil Crop Sci. Soc. Florida. 61: in press.

Other

Brandt, R. C., H.A. Elliott, and G.A. OConnor. 2001. Comparative evaluation of water extractable phosphorus in biosolids and livestock manures. Poster. Southern Extension-Research Activity (SERA-17) annual committee meeting, State College, PA. June 19-20.

Taylor, M. and H.A. Elliott. 2001. Molybdenum content of water treatment residuals. Proc. Residuals and Biosolids Conference, Water Environ. Federation. Feb 21-24, San Diego, CA.

OConnor, G.A., H.A. Elliott, S.R. Brinton, and D. Sarkar. 2001. Plant availability of biosolids-P. American Society of Agronomy, Charlotte, NC. October 21-25. Annual Mtg. Abstracts.

OConnor, G.A. and H.A. Elliott. 2001. Co-Application of biosolids and water treatment residuals. Final Project Report. Florida Dept. of Environmental Protection, Tallahassee, FL.

OConnor, G.A. and H.A. Elliott. 2002. Co-application of biosolids and water treatment residuals. World Congress of Soil Science Proceedings. Bangkok, Thailand. August 13-16.

Attachments

Land Grant Participating States/Institutions

DE, MA, NH, NJ, NY, PA

Non Land Grant Participating States/Institutions