February 28, 2002
Submitted by: Ellen Z. Harrison, Director, Cornell Waste Management Institute, 100 Rice Hall, Ithaca, NY 14853
On behalf of:
David Bouldin, Professor Emeritus, Dept. of Crop and Soil Science, Cornell University
Jim Gillett, Professor, Dept. of Natural Resources, Cornell University
Murray McBride, Professor, Dept. of Crop and Soil Science, Cornell University
David Pimentel, Professor, Dept. of Entomology, Cornell University
Joe Regenstein, Professor, Dept. of Food Science, Cornell University
Thank you for this opportunity to comment on the proposed revisions to the Part 360 Rules. Many of us have eagerly awaited these revisions. We are pleased that the department has persevered and has been able to bring them forward. In our work we have become familiar with programs in many other states, and we believe that the NYS DEC has a progressive program for the management of organic residuals of which it should be proud.
These revisions have been in the works for many years. Because this is a dynamic field, we would hope that DEC will undertake more frequent reviews and revisions as technology and knowledge changes.
As the Land Grant University for NYS, many of the faculty in the College of Agriculture and Life Sciences at Cornell have substantial knowledge and interest in the issues which these regulations address. Some of us have been in contact with DEC staff over the past several years to discuss some of these issues. We are disappointed that much of what we discussed and presented did not find its way into the proposed revisions. We are particularly surprised that the expertise at Cornell was not tapped by DEC in developing a proposed standard for molybdenum. Potential impact on dairy cattle is the primary concern for molybdenum added to NYS soils. Since dairy is the major agricultural industry in NYS, ensuring that the health of that industry is protected by these rules is of major importance. Recognizing the importance of this issue for NYS agriculture, several of us have been engaged in research pertaining to the relationship between sludge use and molybdenum in soils and crops. We would welcome the opportunity to work with DEC on this and other aspects.
Please feel free to contact me if I can be of assistance in clarifying any of these comments or in otherwise providing any assistance.
Ellen Z. Harrison
Establishment of cumulative limits that are appropriate for preventing phytotoxicity. The limits for the phytotoxic elements Ni, Cu, and Zn in the proposed rules are similar to those suggested in the 1985 NE guidelines document out of Penn State. (We are incorporating that document into the record by this reference. We believe that DEC already has a copy, but if not, we would be happy to provide a copy.) Those recommendations represent the views of many soil and crop scientists, and, in particular, address Northeast conditions.
Requirements for soil testing. The concentrations of a contaminant in soil is the concern for a number of the regulated contaminants. Thus measuring soil concentrations rather than relying on calculations based on loading, and on fate and transport is desirable. The requirement in the proposed rule for soil testing at land application sites is a step in the right direction, although it is not clear how these data will be used. In the future, for both these rules and other DEC programs, we suggest that soil quality criteria and standards be developed.
We suggest that the soil sampling as proposed, one composite sample representing 50 acres, is too coarse a sampling scheme to provide adequate information. In developing certified nutrient management plans, it is a requirement that the recommendations for soil sampling published by the state’s land grant university be followed. The recommendations from Cornell are to take 15-20 subsamples from each area that differs in cropping, soil, or past management. This area is usually no larger than 5-10 acres due to the variability caused by soil forming processes and human practices. Soil testing should include the agronomic series (nitrate, pH, K, P, Ca, Mg, Zn, and soluble salts). These tests are inexpensive and would provide information that could help assess the agronomic rate of application. Recently collected data on fields to which N-Viro was applied showed large variation in the concentration of measured parameters (pH, Mo, and other metals) indicating uneven application. Thus 1 sample/50 acres would not provide meaningful data.
Requirements for monitoring of organic chemicals. The proposed required testing of materials for some organic chemicals is an important step, particularly since sludges and some other organic residuals contain inputs from industrial sources that may include toxic organic chemicals. Discharges from homes and streets that enter sewage systems may also convey these types of contaminants. Since these chemicals are not regulated and thus not monitored in sludges, we lack the data needed to consider whether they may be present in sludges. These data are a necessary step prior to considering whether they may be there in concentrations that represent a potential risk to health or the environment. There is a need to monitor sludges for organic contaminants, especially since many are preferentially deposited into the sludge rather than remaining in the wastewater.
As proposed, however, we are concerned that the list of chemicals is not particularly suited to address the chemicals that are potentially found in sludges. The nature of the wastewater process is such that we do not expect to see volatile chemicals concentrate in sludges, whereas those with an affinity for organic matter will be preferentially deposited in the sludges. We suggest that the list of chemicals be revised to include persistent, bioaccumulative, lipophilic organics. There are some data generated in Europe and Canada where screening of sludges has taken place. (We are incorporating these into the record, by reference to them. However, since they are long documents, we are not sending a copy at this time, but would be pleased to provide these if they are not already available to you) While there may be some differences between those sludges and what might be expected in NYS, a review of those studies would assist in the selection of chemicals to potentially be monitored. Some recent research in the US has demonstrated the presence of surfactants (Laguardia, Hale – appended). Of particular concern are those based on nonylphenols because they are estrogenic, present in high concentrations in sludges, and their degradation products are more toxic than the parent compounds. Brominated flame retardants have also been detected in sludges (Laguardia, appended). The penta forms are of particular concern due to their bioaccumulative and persistent nature. Levels in breast milk are rising. We would also suggest that the DEC urge the USEPA to do a new survey of sewage sludges since the 1988 survey (the last relatively comprehensive survey) is out of date and used methods inadequate to detect a number of chemicals.
Requirements for incorporation of sludges. This is especially important in light of the numerous incidents around the US in which neighbors of some Class B application sites are reporting illness that may be associated with airborne contaminants and pathogens. Unfortunately there have been no systematic investigations of any of these incidents, so it is not known what conditions may lead to problems. It would seem reasonable to suggest that incorporation would be helpful, although the methods and timing of incorporation may be important to minimize launching of contaminants and pathogens into the air.
The requirement with respect to incorporation should be extended to a prohibition on application to pastures. Ingestion of lipophilic toxic organics by grazing animals and the subsequent transfer into milk and meat is the most significant potential health concern associated with these chemicals and application of sludges. Since these chemicals may be present in Class A products regulated under section 360-5, this same prohibition should be extended to sludge products as well as direct land application. Many countries do not allow pasture application. This prohibition would also limit the potential for transmission of diseases to grazing livestock from Class B materials. It seems inconsistent in the draft regulations to have an incorporation requirement while at the same time allowing animals to graze after 30 days. If it is not surface applied to pasture, it is hard to conceive of such a grazing scenario. The National Research Council (1996) called into question the adequacy of the 30 day restriction.
Setbacks. Requiring setbacks for land application from watercourses, residences, wells etc. is appropriate. It is not clear that the proposed distances will be protective, but they are at least an attempt to protect neighbors and the environment.
Label requirements. The ability of consumers to readily obtain information about products is important and we strongly support this requirement in the proposed rules. The label would presumably state that sludge derived products can not be used on food crops unless specified waiting periods are observed.
Explicit requirements for out-of-state products. Creating a level playing field for all products sold or used in NYS is highly appropriate. Consumers should be assured that all products sold in NYS meet the same standards. We thus support extending to out-of-state products the same requirements as for products manufactured in NYS. For products such as Milorganite which are sold in garden stores in NYS, we assume that if the proposed rules are adopted, that unless the product has been stored for the waiting periods specified, the bag would have to state that the product cannot be used on food crops.
Prohibition against the use of cement kiln dusts from facilities that burn hazardous wastes. The potential for these dusts to contain higher levels of toxics than other dusts makes it prudent to exclude them from land application.
In the last several years concerns about the water pollution resulting from nutrients (N and P) on livestock farms has resulted in the development of federal and state requirements for nutrient management. In NYS a procedure is in place whereby comprehensive nutrient management plans are required for an increasing number of livestock farms. These plans are prepared and certified by trained and certified professionals. They address all nutrient sources, and address not only nitrogen, but phosphorus. We propose that these same requirements and plans be used in evaluating applications of residuals under the Part 360 rules. Since a certification program has already been developed, it would ensure that persons with specific agricultural expertise analyze the agronomic needs and that they do so in light of all of the nutrient sources being used by the farm. It would also appropriately address P, which is a concern not only in the NYC watershed, but in many watersheds tributary to lakes in NYS.
Currently, all farms over 1000 animal units (AU) must have a Concentrated Animal Feeding Operation (CAFO) plan. A CAFO plan must follow Natural Resources Conservation Service (NRCS) standards and specifications. The standards require, among many other things, proper agronomic accounting for nutrients from all sources. In NYS the net is cast more broadly: 1) the NY SPDES permit also requires permits from operations that "discharge" and are 300-999 AU; and 2) farms of any size that are involved in state or federal cost sharing programs must meet NRCS standards. Furthermore, EPA and NRCS, via the Clean Water Action Plan, have expressed the desire that by 2009, all AFO's (animal feeding operations) follow a nutrient management plan that meets NRCS specs. (See in particular NY590 and NY633 – attached.) http://www.ny.nrcs.usda.gov/standards/index.htm, http://www.ny.nrcs.usda.gov/standards/cnmp_pol.htm).
Any farm using sludge-derived product ought to be using this material based on a nutrient management plan. It would seem appropriate to require the same for sludge and also for septage additions, as well as other materials applied in bulk such as paper sludges. Much of the bulk land application of sludges and other organic residuals in NYS is to livestock farms where nutrient management plans are or will soon be required due to manure generation. Thus extending the requirement to sludge applications would not increase the burden, but, in fact, could make it simpler. Since nutrients may already be out of balance on livestock farms (more nutrients than needed to balance crop needs), it is particularly important to take a comprehensive look at sludge additions.
It would seem appropriate to require similar plans – prepared by certified nutrient planners – to be a part of the requirements for bulk applications of sludges, septage, and other regulated residuals to non-livestock farms as well. These farms would not otherwise fall under certified nutrient management plan requirements. However, under the proposed rules they are required to analyze their agronomic needs, so changing the rules to require that a plan be developed by a certified planner is logical and would promote consistency. Where these organic residuals are to be applied to only a small segment of the farm, the plan could address those segments.
Some additional reasons for the suggestion follow.
1) The general thrust of the present DEC document is that agronomic rates are set by the nitrogen requirement of the crop. But in the case of the NY City watersheds, P is designated as the most critical nutrient. We are bordered by Lakes Erie and Ontario, and there are many interior lake sheds/ watersheds in which P is a critical element. With most agronomic situations in NY sludge meeting the N requirement of a crop will contain P far in excess of agronomic requirement for P. The land grant college in NY in cooperation with NRCS is using a prototype P index as part of the certified nutrient management plans. It seems reasonable to begin to use this as a management tool in all watersheds.
2) The guidance given in the present document with respect to N does not require a rigorous evaluation of the N supplied by the soil and by residual effects of recent applications of manure and/or legume crops, nor even current applications of manures and fertilizers, and legume crops. This is a very technical issue best evaluated by persons certified to deal with these complexities. The certified agent will presumably do such analyses and insure that sludges are used beneficially, consistent with environment quality. This should provide a level of assurance to the DEC personnel charged with reviewing land application permits, most of whom have little agricultural expertise.
3) Consistency between sludge (and other regulated residuals) and manure (and fertilizer) would be promoted by adopting the requirement suggested.
We have been conducting research on molybdenum levels in soils and uptake of Mo into crops, and have looked at the potential impact of Mo on dairy cattle nutrition. This work suggests the need for significantly tighter standards for molybdenum in NYS than the proposed 52 ppm. We find that despite significant losses of Mo (presumably through leaching), residual levels of Mo persist for more than 20 years after sludge additions, resulting in elevated levels of Mo in crops grown on the sites. Soil Mo levels of only 2.5 mg/kg were associated with crop levels ranging from 2.6 in corn leaves to 25.5 in soybean seeds (McBride et al., 2000, appended).
The regulatory limits selected will depend on the assumptions made regarding animal diet and uptake, and dietary copper supplements. This is in part a policy determination of whether the goal is to be protective of the average NYS dairy herd, or rather to be more protective, and address those farms which might represent a relatively high level of exposure (higher intake of sludge-amended leguminous forage for example) and/or a low level of herd management. The following discussion addresses some of these considerations.
Cattle are the most sensitive to excess Mo and dairy cattle are the primary concern in NYS. It is estimated that the average NYS dairy cow eats approximately 60-70% forage, and that this is about 1/2 corn, and 1/2 legumes and/or grasses. Soybean meal, which contains relatively high Mo (see Chase, appended), makes up about 5-7% of the diet. Other dietary sources are relatively low in Mo. At certain times in the cow’s cycle (late in lactation, for example), the percentage of forage may rise to 80-90% and be comprised primarily of legumes (particularly in southern NYS). This may persist for about 1-2 months. Unfortunately there does not appear to be information on the significance of the duration of exposure to high Mo on animal health, so whether there would be significant health or reproductive implications of a month or two of excessive Mo intake (if that forage were from sludge-amended land and high in Mo) is not known. There is an increasing emphasis on grazing versus using imported feed on NYS farms. This is, in part, a move towards balancing the nutrient inputs and outputs as well as a means to address acid problems caused by feeding grains. (Source: Professor Larry Chase, Dept. of Animal Science, Cornell University, 2002, personal communication.) Thus we would project an increasing percentage of cattle diets will come from on-site.
Uptake of Mo into crops varies with crop and sludge type. Higher uptake is associated with legumes and with alkaline sludges. Estimated uptake coefficients (UC) for legumes is approximately 4 according to O’Connor (2001). This value is in reasonable agreement with that calculated by McBride (2000, appended) for red clover and alkaline sludge (4.27). Somewhat higher levels were measured by Stehouwer for alfalfa in fields to which N-Viro type sludge was added (2001, presentation to NE 1001, appended).
The issue with Mo is that it can depress Cu absorption, especially in the presence of S. The addition of sludges tends to increase S and Mo in soils and crops, and while sludge addition may increase Cu in soils, data show that the increased Cu is not reflected as an increased uptake into the crops (McBride et al, 2000, appended). Thus, sludge additions will tend to decrease the ratio of Cu to Mo in the crops, in some cases bringing the ratio below the 4:1 considered desirable and the 2:1 considered minimal. Since S concentrations are an important determinant of impacts and sludges are a significant source of S, consideration should be given to establishing a standard for S, or at least for monitoring for it.
The National Research Council has suggested that 10ppm Mo in cattle diets is a lowest effect level, so that at lower levels we would expect subtle, subclinical effects (O’Connor et at, 2001, appended). Calculations of expected Mo concentrations in cattle diet show that under various assumptions, a sludge limit of 52ppm would result in dietary intakes of somewhere between 17.6 and 58.5ppm. A spread sheet is being submitted with these comments that poses several alternative assumptions including: 100% or 60% of the diet as forage, 50% of the forage is legumes, 50% is grass, UC for the legumes is 4, UC for the grass is 0.5, sludge concentration is diluted 50% by mixing with soil, no leaching or 50% leaching, the non-forage diet has 1.8ppm Mo. Depending on which set of assumptions one selects, sludge concentrations of 8ppm up to 27ppm would result in dietary intakes slightly below 10ppm.
Reviewing the paper by O’Connor et al (2001) that develops a proposed sludge Mo standard of 40ppm, there are several assumptions made which we question. One is that only 20% of the diet comes from sludge-amended soils. This seems to be based on calculations having to do with how much land is available. For a farm that uses sludge or sludge products, this is not relevant. It is also based on the hypothesis that sludges would be used only once every 3-5 years, which is perhaps the case for some products but not for others. Thus the assumption that 20% percent of the diet is grown on sludged soils is not a reasonable assumption. The paper also emphasizes that where Mo is high, farmers know to supplement diets with Cu. However, farmers would not know about the Mo/sludge issue and so would not be providing more than normal Cu supplementation.
Summary: The proposed limits for As, Cd, and Hg in the proposed rules and the lack of standards for any organic chemical are not adequately protective of human health, particularly for the farm family applying sludges and the home gardener. There is no explicit statement of how the proposed standards were developed (are they based on an analysis of risk? or of achievable levels? Or?). If they are risk based, who is the receptor for which risk that is being assessed? We are assuming that the rules would seek to be at least strict enough to achieve an acceptable risk to the farm family.
We recognize and appreciate that the proposed standards for Cd and Hg are more restrictive than those in the EPA 503 rules. However, the proposed levels are still higher than what we believe would provide appropriate protection. . In the risk assessment performed to develop the 503 standards, risks were not summed across the various pathways to which a receptor may be simultaneously exposed. The standards were set such that each pathway was assessed independently. However, the receptor is generally exposed simultaneously via a number of pathways.
The risk analyses on which several of the proposed standards appear to be based do not adequately address the particular risks to the farm family. A discussion of the difference in diet between that used by EPA in developing standards and that relevant to a farm family is used here as an example. The appended analysis of the dioxin risk assessment also addresses the particular risks to the farm family.
The vegetable consumption in the average diet of non-metropolitan populations from the late 1970’s was used by the USEPA to calculate crop consumption in the risk assessment. A total dietary intake of 125 g DW/day of potatoes, leafy vegetables, legumes, root vegetables, garden fruits, peanuts, and grains/cereals is used in the risk assessment.
Use of average dietary values significantly underestimates consumption for the reasonable maximum exposed person. Large variations in vegetable and fruit consumption are evident. For example, data from 1989-91 show that for the non-metropolitan resident, the 90th %ile intake is nearly twice the mean daily vegetable consumption value and the 99th %ile is more than 5 times the average (USEPA, Exposure Factors Handbook, 1997). While these are based on data collected over a relatively short time, which may overestimate the upper bound values, they nonetheless demonstrate the failure of the mean to represent the high-end vegetable eaters, including vegetarians. No data specific to vegetarians, the likely RME receptor, could be found.
There is evidence, moreover, that the particular population of the home gardener, especially farm households who garden, consume far higher amounts of vegetables than the non-metropolitan population in general. Mean vegetable consumption is nearly 2.5 times higher for farm households than for the non-metropolitan population and the 95 %ile is nearly four times greater. Data show that 59% of farm households raise homegrown produce (USEPA, 1997).
The table below demonstrates the large difference between the quantity of vegetables eaten by the non-metropolitan resident versus the farm gardener. It also shows the large variation between the mean and 95 %iles in the short-term studies.
Home produced consumption
11.8 g/kg-day=95 %ile
38 g/dg/day=95 %ile
Produce consumption estimates from EPA Handbook, 1997
Our comments are based in part on analyses in the appended papers (Harrison, McBride and Bouldin, 1999; Harrison, 2000).
A few specifics:
1. Arsenic should be evaluated as a carcinogen. In such an analysis, contaminant levels on the order of 10 ppm seem more in line with appropriate risk levels.
2. If sludge products are allowed on home vegetable gardens, then cadmium exposure needs to factored into a much higher vegetable intake for home gardeners and, in particular, for farm families.
Persons working in fields or on other sites where Class B sludges have been applied may be exposed to pathogens. There should be a requirement for disclosure of risk (in a language which they understand) and for providing information to workers on how to minimize those risks. Handwashing facilities should be required for their use.
The proposed rules eliminate the standard for PCBs and allow DEC to set PCB standards on a case-by-case basis. It is not clear why the concentration limit for PCBs were eliminated, nor what basis will be used to set standards if PCBs are detected. The proposed rules require testing for 7 PCB congeners. Why these particular congeners were selected is not clear. Pressure to allow spreading of PCB contaminated materials is likely to increase with dredging of the Hudson. It seems prudent to maintain a standard rather than eliminate it at this time.
We recognize and agree with requirements for more frequent testing than that required by EPA for small POTWs. Data indicate that variability is greater for small treatment plants. In large plants, the variation that might be caused by a single discharger’s actions is buffered by the large flow from an array of sources. We would thus support more frequent testing of small facilities. We are also concerned that the provision to allow reduced testing after 2 years is not advisable. Users need to have these data.
Managing and reviewing the volumes of data seems to be a problem, given the limited staff at DEC. We suggest that electronic submission of data be required, which could aid in simplifying this requirement.
Some of the test methods specified allow one to choose from several methods, some of which are antiquated. Lead, cadmium, and molybdenum are of concern because the levels can be quite low in sludge yet still be a health concern. The most modern method of SW-6020 is not specified for these pollutants which is ICP-MS based. The ICP-OES method 6010 does not specify an axial torch which allows you to get close to the detection limits of 6020. Also, you can choose to use direct aspiration AA 7130 (for Cd), 7420 (for Pb) or 7480 (for Mo) for these elements which would have a detection limit 10 or more times less sensitive than the ICP methods. For As and Se you can also choose an inappropriate (read high detection limit) method which is 6010 ICP-OES without the axial torch or a hydride method specified. In summary, the rules as they are now written allow you to choose an out of date insensitive method. (Note: ICP-MS designates a mass spectrometer on the ICP whereas ICP-OES is an optical emission detector on the instrument.) We would recommend that insensitive inappropriate methods such as direct aspiration AA and radial torch ICP not be given as a choice for Cd, Pb, Mo, As and Se.
Pathogen testing as proposed retains the use of either Salmonella or E. coli to meet Class A requirements. This provision has been questioned by a number of knowledgeable sources. Beyond the question of whether “either/or” should be allowed, there is a problem with the accuracy of tests to determine compliance (Yanko, et al, 1995). The method for Salmonella specified in the 503 rules are not reliable for ensuring compliance with the standards.
The whole basis on which testing for “indicator” pathogens is based has been called into question (EPA Emerging Pathogens workshop, June 2001, copy sent via email). At this time alternatives have not been developed. We urge DEC to remain at the forefront and to consider modifications to the pathogen testing requirements over the next several years as new developments take place. In the mean time we suggest that the requirement be to meet both E. coli and Salmonella standards.
One measure used by many other countries and Canadian provinces to reduce the overall risk is to limit the amount that can be applied in any one year and/or in a period of several years. This is not based on agronomic calculations, but rather on a precautionary approach, and, perhaps, also as a means to address the concerns of neighbors. We suggest that such a limit be imposed in NYS. An application of 10 tons/acre within a 3 year period might be a reasonable limit.
We believe that it is sound policy to direct the use of sludges and sludge products, which contain an array of chemicals discharged by homes and industries, to low risk uses, and to restrict their use on food crops and in home gardens. We thus support a prohibition on the use of sludges and sludge products on food crops. The proposed rules require a holding period before use for both sludges and sludge products, promoting consistency. However, where the concerns are not for pathogens but for chemical contaminants, waiting periods are not relevant and sludge products are likely to have the same array of contaminants as land applied sludges.
In addition to concerns about the health-based standards being too high as discussed above, we believe that the proposed standards for the phytotoxic elements Cu, Ni, and Zn are too high. If composts containing these levels were applied at reasonable rates for even several years, soil concentrations would reach levels detrimental to crop growth. Fortunately most composts are far less contaminated. Recently data is being generated that suggest that soils with repeated manure applications are reaching copper levels of concern. The data we have indicates that most manures contain copper at levels far less than the proposed 1500 ppm (500 ppm is an elevated level in manures) and manure is generally applied at rates significantly lower than composts. Calculations should be performed for these elements tracking back from acceptable soil levels. Alternatively, restrictions could be placed on the quantity of composts that could be applied. This is not a practical approach for home gardeners.
Land application should not be allowed on floodplains or on soils exceeding 75% moisture field capacity. Both situations would favor runoff and potential for human pathogens to enter the watercourses.
We believe that the DEC proposal to require tracking of land application is desirable. We think that the requirement should be extended to all bulk applications of sludge products and septage. We understand and appreciate that tracking is required as part of the permit for the N-Viro Onondaga facility. Presumably since the Hydropress product comes from out-of-state, no tracking is required for NYS applications. This uneven situation could be remedied by requiring tracking in the 360 rules rather than in the permit. Molybdenum availability is greater from these alkaline products and molybdenum in sludge-amended soils is a concern as addressed above. This supports the need to track the application of these products.
An analysis of septage quality (Harrison and Moffe, appended) suggests that regulation of land application of septage deserves more scrutiny. The proposed rules would extend a registration requirement to small haulers. However, more extensive regulation might be appropriate. There seems to be general agreement that this practice is less desirable from an environmental standpoint than discharging septage to a wastewater treatment plant. It would seem reasonable to allow land application only when a case can be successfully made to the DEC that delivery to a wastewater treatment plant is not feasible. It would also seem reasonable to require septage application pursuant to a certified nutrient management plan (see above). Neighbors to sites where it septage is proposed that septage be applied should be notified prior to approval as should the municipality in which the application site is located.
Spread sheet with molybdenum calculations – emailed.
References cited and sent under separate cover or available as noted:
2002 Cornell Guide for Integrated Field Crop Management. 2002. Land Application of Sewage Sludges. A Cornell Cooperative Extension publication 33-37.
Baveye, P., M. B. McBride, D. R. Bouldin, T. D. Hinesly, M. S. A. Dahdoh, and M. F. Abdel-Sabour. 1999. Mass Balance and Distribution of Sludge-borne Trace Elements in a Silt Loam Soil Following Long-term Applications of Sewage Sludge. The Science of the Total Environment 227:13-28.
Bouldin, D. R. Use of Sludges in Agriculture and Risk of Reduction of Crop Yields. Department of Soil, Crop and Atmospheric Science, Cornell University.
Bouldin, D. R. 1997. Why Guidelines for Beneficial Use of Sludges in Agriculture are Different and Estimates of Alternatives. Soil Sciences Society of North Carolina Proceedings Vol. 40.
Cherney, J. H., M. McBride, D. J. R. Cherney and E. Z. Harrison. 2001. Lime-Treated Sludge-Should Dairy Farmers be Concerned? What’s Cropping Up 11:1.
Chase, L., 2002. Molybdenum in Dairy Cattle Nutrition, draft. Discussion Paper, Dept of Animal Science. Cornell University.
Danish Environmental Protection Agency. 1997. Use of Waste Products in Agriculture. Environmental Project No. 366. Ministry of Environment and Energy, Denmark (cited in text. We will provide a copy if requested).
Hale, R. C. and M. J. LaGuardia. 2002. Synthetic Organic Pollutants in Land-Applied Sewage Sludges. Directions in Science 1:10-13.
Hale, R. C., M. J. LaGuardia, E. P. Harvey, M. O. Gaylor, T. Matteson-Mainor and W. H. Duff. 2001. Persistent Pollutants in Land-Applied Sludges. Nature 412:140-141.
Harrison, E. Z, M. B. McBride and D. R. Bouldin. 1999. Land Application of Sewage Sludges: An Appraisal of the US Regulations. Int. J. Environment and Pollution Vol. 11, No. 1.
Harrison, E. Z. 2000. Peer Review of Dioxin Risk Assessment. http://cwmi.css.cornell.edu/Sludge/review.html.
Harrison, E. Z., M. B. McBride and D. R. Bouldin. 1999. The Case for Caution. http://cwmi.css.cornell.edu/PDFS/LandApp.pdf.
Harrison, E. Z. and M. Moffe. 2002. draft. Septage Quality and Land Application. Submitted for publication.
LaGuardia, M. J., R. C. Hale, E. Harvey and T. Matteson-Mainor. 2001. Alkylphenol Ethoxylate Degradation Products in Land Applied Sewage Sludge (Biosolids). Environmental Science and Technology 35 (24) 4798-4804.
McBride, M. B. 1998. Growing Food Crops on Sludge-amended Soils: Problems with the US Environmental Protection Agency Methods of Estimating Toxic Metal Transfer. Environmental Toxicology and Chemistry 17 (11): 2274-2281.
McBride, M. B. 1998. Soluble Trace Metals in Alkaline Stabilized Sludge Products. Journal of Environmental Quality 27:578-584.
McBride, M. B. 1995. Toxic Metal Accumulation from Agricultural Use of Sludge: Are U.S. EPA Regulations Protective? Journal of Environmental Quality 24:5-18.
McBride, M. B., B. K. Richards, T. S. Steenhuis, J. J. Russo and S. Sauve. 1997. Mobility and Solubility of Toxic Metals and Nutrients in Soil Fifteen Years After Sludge Application. Soil Science 162 (7): 487-500.
McBride, M. B., B. K. Richards, T. S. Steenhuis and G. Spiers. 2000. Molybdenum Uptake by Forage Crops Grown on Sewage Sludge - Amended Soils in the Field and Greenhouse. . Journal of Environmental Quality 29:848-854.
Natural Resources Conservation Service. 1999. Conservation Practice Standard. Nutrient Management. Code 590.
Natural Resources Conservation Service. 2001. Conservation Practice Standard. Waste Utilization. Code NY633.
O’Connor, G. A., R. B. Brobst, R. L. Chaney, R. L. Kincaid, L. R. McDowell, G. M. Pierzynski, A. Rubin and G. G. Van Riper. 2001. A Modified Risk Assessment to Establish Molybdenum Standards for Land Application of Biosolids. J. Environ. Qual. 30:1490-1507.
Richards, B. K., J. H. Peverly, T. S. Steenhuis, and B. N. Liebowitz. 1997. Effect of Processing Mode on Trace Elements in Dewatered Sludge Products. Journal of Environmental Quality 26:782-788.
Richards, B. K., T. S. Steenhuis, J. H. Peverly, M. B. McBride. 2000. Effect of Sludge Processing Mode, Soil Texture and Soil pH on Metal Mobility in Undisturbed Soil Columns Under Accelerated Loading. Environmental Pollution 109 (2) 327-346.
Richards, B. K., T. S. Steenhuis, J. H. Peverly, M. B. McBride. 1998. Metal Mobility at an Old, Heavily-loaded Sludge Application Site. Environmental Pollution 99:365-377.
Steenhuis, T. S., M. B. McBride, B. K. Richards and E. Z. Harrison. 1999. Trace Metal Retention in the Incorporation Zone of Land-Applied Sludge. Environmental Science & Technology 33 (8): 1171-1174
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cc: Erin Crotty, Commissioner, NYSDEC
Nathan Rudgers, Commissioner, NYS DAM
Richard Morse, Legislative Commission on Solid Waste Management
Stephen Hammond, Director, Division of Solid and Hazardous Materials, NYSDEC
Charlie Kruzansky, Cornell University Office of Govt. Affairs