Friday, March 27, 1998


Humic substances are the brown biopolymers in plants, sediments, soils that confer special properties like water retention, solute sorption and metal binding. Temperate climates depend on the water retaining properties of soils, and the properties of humic substances directly affect the environment and human health.

The first Seminar on Humic Substances was held at Northeastern University, Boston, Massachusetts, USA on March 21, 1997. The special guest lecturer was Dr. Robert Wershaw of the US Geological Survey, Denver, Colorado, a well-known expert on humic substances. The first Seminar actually was organized because Dr. Wershaw was in the neighborhood to meet his daughter Leah (a Nursing major at Northeastern) and go on his way to a wedding in New York City. It was a happy beginning.

The Program of the first Seminar covered a range of topics that intrigued an audience of about 60 from the region. Many disciplines were represented and we all learned something from the presentations and discussions. There was sharp debate, particularly on HS structures and origins, but the general atmosphere of the meeting was warm and cordial. So much so that we decided to try to make the Northeastern Humic Substances Seminar an annual event.

The study of humic substances is a worldwide activity with many implications for our survival, the environment and human health. Much has happened in humic substance research in the last year, particularly with regard to trying to deduce HS structures with the help of sophisticated molecular modelling. Humic acids actually may be oxidized glycoproteins (they always have polysaccharide and protein components). Studies of highly purified HS indicate that they have reproducible and accountable adsorptive properties and appear to have common metal binding sites. Humic substances are natural fertilizers and an industry based on HS continues to grow.

As this year’s Program shows, the Humic Substance Seminar also has grown. The 1998 program is an interesting spectrum of topics that demonstrates the breadth and depth of contemporary HS research and application.

We are especially pleased to have the company of Drs. James Alberts (President), Michael Hayes (Immediate Past President) and C. Edward Clapp (Treasurer) of the International Humic Substances Society, together with authors from Italy and Norway. As they say in Egypt, "You are most welcome."

It is a pleasure to acknowledge support and encouragement from our sponsors and to thank Northeastern University for providing its fine facilities. The authors are thanked for their contributions. With your support, the Humic Substance Seminar will become an annual event. If it does, we’ll do our best to maintain the fine atmosphere of Seminar I. Thank you for coming and enjoy your stay.

Wolfgang Ziechmann     Geoffrey Davies               Elham Ghabbour
Honorary Chair           Chair                               Co-Chair
                                                                                                                 March, 1998





Michael H. B. Hayes

School of Chemistry, University of Birmingham, Birmingham B15 2TT, UK

Humic substances (HS) are contained in all soils, waters, and organic-containing sediments. Such substances can arise from chemical and biological synthesis processes, and popular concepts consider HS to be gross mixtures of macromolecular substances. However, there is growing evidence to indicate that there has been substantial over elaboration with regard to the gross mixture concept, and it now seems likely that where the same sources and same environmental conditions (e.g., soil type and climate) prevail, the HS formed are less complex than was previously considered. Any study of humic composition and structure must begin with their isolation and fractionation. Exhaustive extractions from soil using logical sequences of solvents and applications of XAD resins in tandem procedures allow fractions to be obtained which have some degrees of homogeneity with regard to charge densities and functionalities, but not necessarily with regard to molecular sizes. There is some evidence to suggest that HS are pseudo-macromolecular structures derived from a self-assembly of molecules of low molecular weight (MW), perhaps <1000 Daltons, but that concept has not been confirmed. Uses of fluoresence and NMR spectroscopy, and especially CPMAS 13C NMR, show compositional (especially functionality) similarities and differences between samples. Recent applications of various forms of 2-D NMR suggest that it will be possible to resolve component structures in at least some of the fractions. This has been evident especially in the cases of fractions derived from lignin and tannin structures where humification has not progressed to the final (most resistant to biological degradation) product. Analyses of amino acids and sugars compositions are contributing significantly to the roles of these, and probably also of peptides, proteins, hemicelluloses, oligosaccharides and polysaccharides, in the genesis of HS. Useful extrapolations with regard to compositions can be made from identifications of digest products of chemical degradations, but these extrapolations are meaningful only when account is taken of the degradation mechanisms involved.



Jingdong Mao,1 Weiguo Wu,2 Klaus Schmidt-Rohr,2 Geoffrey Davies,3 Elham A. Ghabbour3 and Baoshan Xing1

Department of Plant and Soil Sciences, University of Massachusetts Amherst, MA 01003
2Department of Polymer Science and Engineering, University of Massachusetts Amherst, MA 01003
3Chemistry Department and the Barnett Institute, Northeastern University Boston, MA 02115

Structural and elemental information is critical in determining the reactivity of humic acids (HA) with heavy metals and organic contaminants. In this paper we employed solid-state 13C NMR and chemical analysis to determine structure, functional groups, and elemental composition of various HAs. Results from the two methods are compared. The CP/MAS and Bloch decay were used to obtain NMR spectra and ratios of sp3 C to sp2 C. Chemical shifts were assigned to corresponding functional group carbons according to Stevenson(1), Cook et al.(2), and Breitmaier and Voelter(3). Elemental composition (C, H, N, O) of HA was computed from the Bloch decay spectra using a deconvolution technique. Functional groups and total acidities of HA were measured by wet chemistry methods and elemental composition with an elemental analyzer. Comparisons between the two methods revealed good agreement for some HA but discrepancy for others. This suggests that paramagnetic centers (e.g., Fe) in HA may complicate the NMR data and their interpretation and/or that the deconvolution technique may require improvement. The ratios of sp3 C to sp2 C computed from NMR spectra appear to be larger than the ratios from several HA structural models in the literature. This indicates the need for some revision of existing HA models. Details of NMR parameters, the deconvolution technique, and the theory and equations for calculating elemental composition from NMR spectra will be discussed. The effect of paramagnetic centers on NMR spectra of HA also will be addressed.

1. Stevenson, F. J. Humus Chemistry. Second Edn.,Wiley, New York (1994).
2. Cook, R.L., Langford, C.H., Yamdagni, R., and Preston, C.M. Anal. Chem. 68, 3979-3986 (1996).
3. Breitmaier E. and Voelter W. Carbon-13 NMR Spectroscopy, High-Resolution Methods and Applications in Organic Chemistry and Biochemistry. VCH, New York (1987).



Leonid G. Akim1 and George W. Bailey2

National Research Council, c/o USEPA, Athens, GA 30605-2700
2US Environmental Protection Agency, Athens, GA 30605-2700

The conformational properties of model humic substances and their energetic interactions with mineral surfaces are being characterized using a computational chemistry approach. The humic substance models were developed starting from lignin and lignin-carbohydrate complex models(1). The crystallographic structure of muscovite (i.e., mica, KAl2(Si3Al)O10(OH)2, was used as the mineral model. Specific model humic substances chosen for experiments were an oxidized lignin and a lignin-carbohydrate complex. These polymers were "docked" onto the mica surface as described in (2) to form organo-mineral systems. Molecular mechanics (SYBIL software, Tripos forcefield) and dynamics calculations (simulated annealing, 10 cycles, 1 ps at 700K, and annealing to 200K in 1 ps) were used to simulate sorption processes on the surface and estimate sorption energies. As expected, we found that ionized polymers are more strongly sorbed onto charged mineral surfaces than unionized ones. Computational chemistry has great potential for studying humic substances and their interactions with mineral surfaces.

1. Shevchenko, S. M., Bailey, G. W., J. Mol. Struct., Theochem., 364, 197-208 (1996).
2. Shevchenko, S. M., Bailey, G. W., Modelling sorption of soil organic matter on mineral surfaces; wood-derived polymers on muscovite. In Supramolecular Science, in press (1998).



Maria De Nobili,1 G. Bragato2 and A. Mori2

Dipartimento di Produzione Vegetale e Tecnologie Agrarie, University of Udine, 33100 Udine, Italy
2Istituto Sperimentale per la Nutrizione delle Piante, Sezione di Gorizia, 34140 Gorizia, Italy

In conventional polyacrylamide gel electrophoresis (PAGE), molecular size differences can explain more than 95% of variations in the electrophoretic mobility of fractions of humic substances of reduced molecular weight polydispersity extracted from the same soil. Capillary electrophoresis is, however, entirely peculiar in that specific factors, such as the electro-osmotic flow, can affect not only the efficiency, but also the mechanism of the separation itself. In particular, humic substances, which would naturally migrate towards the anode under the influence of the electric field, are instead driven to the cathode by the electro-osmotic flow generated by the migration of cations near the negatively charged surface of the capillary. Although the main factor influencing the capillary electrophoretic behavior of HS, even under conditions where the normal migration direction is reversed, is still the molecular size, the enormous separation efficiency of capillary electrophoresis allows the detection of significant charge effects when comparing the mobilities of corresponding fractions of reduced molecular size polydispersity of humic substances extracted from different soils. In the present work we examined the electrophoretic behavior of humic substances in coated fused silica capillaries where the electro-osmotic flow was suppressed by reaction of the free silanol groups on the inner capillary surface to give a polyether coating. Fractions of reduced molecular weight polydispersity extracted from three different Histosols, Leonardite and a spodic soil were prepared by multistage ultrafiltration on Amicon YM membranes in the following ranges: 100-300, 50-100, 30-50, 30-10, 10-5 and 5-3 kDa. The absolute mobilities of the fractions were measured either in the presence or absence of different concentrations of polyethylene glycol (PEG) 4000 and 20000 at or above their entanglement threshold. Very good positive linear correlations (R2>0.90) were found between the mobility and the logarithm of the molecular weight of fractions extracted from the same soil; however, the correlation was not significant when corresponding fractions extracted from different soils were examined under the same experimental conditions. The charge densities of the fractions were determined by acid base titration at an ionic strength corresponding to that of the electrophoretic buffer.



Peter Ruiz-Haas,1 Dula Amarasiriwardena1 and Baoshan Xing2

Hampshire College, Amherst, MA 01002
2University of Massachusettes, MA 01003

The study of trace metal complexation properties of humic acids (HAs) is becoming increasingly pertinent in understanding the fate, transport and immobilization of heavy metals in the environment (1,2). Therefore, speciation of heavy metals bound to different humic acid fractions could provide better insight of the mechanisms of metal complexation with HA. In addition, measurement of heavy metals bound to individual HA molecular species is useful in determining HA activity in soil and sediment. Size exclusion chromatography (SEC) has been used for the separation of humic acid molecular fractions (3,4) in aquatic samples. Trace metal bound humic acid fractions in aquatic samples were previously determined by SEC-ICPMS(4). Off-line determination of aluminum bound to aquatic humic acid fractions after separation with SEC was accomplished with graphite furnace atomic absorption spectrometry (GFAAS) (5). This study focuses on the applications of trace metal analysis of HA fractions in soil and compost samples by interfacing of SEC with ICP-MS. Samples of HA were extracted with base from compost, peat, soil and Leonardite. Soils and compost samples were chosen with different degrees of humification and makeup. These samples were characterized by uv-visible spectroscopy (E4/E6 ratios) and diffuse reflectance fourier transform infrared (DRIFT) spectroscopy. Total Pb, As, Cu, Mn, Ni, and Zn concentra-ions in HA were determined by ICP-MS after high pressure/temperature nitric acid digestion. High per-formance SEC (HPSEC) was successfully interfaced to an ICP-MS to identify and quantify heavy metals (Pb, Ni, Cu, Mn, Zn) bound to different molecular HA fractions as separated by the SEC column. Preliminary results show how individual heavy metals are associated with different HA fractions and that these fractions have different heavy metal profiles. The method was then applied for speciation of humic acid bound trace metals in several compost and soil samples to demonstrate potential applications in determining the transport of heavy metals in soil, to develop cost-effective remediation technology, and to better understand micronutrient status in soils.

1. Glaus, M. A., Hummel, W., Van Loon, L. R., Environ. Sci. Technol., 29, 2150 (1995).
2. Zhang, Y -J., Brown, N. D., Livens, F. R., Jones, M. N., Complexing of metal ions by humic substances. In Humic and Fulvic Acids. Eds. Gaffney, J. S., Marley, N. A. and Clark, S. B., American Chemical Society, Washington, 1996.
3. Chen, Y., Aiken, G., O'Loughlin, E., Environ. Sci. Technol., 28, 1853 (1994).
4. Rottmann, L. and Heumann, K. G., , Anal. Chem., 66: 3709 (1994).
5. Zernichow, L. and Lund, W., Anal. Chim. Acta, , 300: 167 (1995).



Liviana Leita1 and Maria De Nobili2

1Istituto Sperimentale per la Nutrizione delle Piante, Sezione di Gorizia, 34140 Gorizia, Italy
2Dipartimento di Produzione Vegetale e Tecnologie Agrarie, University of Udine, 33100 Udine, Italy

We studied the complexation of ferrous and ferric ions by fractions of humic substances of different molecular size (1-10, 10-30, 50-100, 100-300 and >300kDa) obtained by multistage ultrafiltration from the sodium pyrophosphate (pH 7.1) extract of a sphagnum moss peat. Ultrafiltration was performed first in 0.1 M Na4P2O7 till the solution coming out of the cell was colorless, then in distilled water till the conductance of the outflowing liquid was less than 30 μS. Voltammetric measurements were performed at a glassy carbon stationary electrode with 1 mM K3[Fe(CN)6] in the presence of 0.1 M NaClO4 as supporting electrolyte. The reliability of the working electrode responses was periodically checked by recording cyclic voltammograms on solutions containing ferricyanide alone. Amperometric titrations of potassium ferricyanide with increasing aliquots of HS fractions showed after addition of 10 μg organic C a significant depression of both the FeIII-FeII and FeII-FeIII peak currents, together with a cathodic shift of the FeII reduction peak and a symmetrical anodic shift of the associated FeII oxidation peak. Both the ΔEp values and the amount of organic carbon causing the maximum peak displacement varied for the different HS fractions. The sigmoidal shape progressively attained by both the reduction and the oxidation peaks is consistent with the occurrence of electrochemical processes involving a slow homogeneous chemical reaction preceding the electron transfer step. This is confirmed by the fact that the normalized peak currents did not remain constant with increasing scan rate. The slow preceding chemical reaction is probably a preliminary release of iron ions from humate complexes. Changes of the uv-visible spectra of the [Fe(CN)6]3- complex relative to the sharp charge transfer bands at 200 and 225 nm during addition of HS fractions showed an alteration of the inner coordination sphere of FeIII. Relative stability constants were calculated from the intercepts of the straight lines obtained by plotting ΔEp + 0.059 log(iM/iML) vs. log [L]. Both FeII- and FeIII-humate complexes exhibit greater stability of low molecular weight Fe-humate complexes, a larger complexation capacity of low molecular weight HS fractions and particularly of the 1-10 kDa fraction.



Elham A. Ghabbour,1,2 Geoffrey Davies,2 Melissa E. Goodwillie,2* Kelly O’Donaughy,2* and Tammy L. Smith2*

Soil Salinity Laboratory, Agricultural Research Center, Bacos, Alexandria 21616, Egypt
2The Barnett Institute and the Chemistry Department, Northeastern University, Boston, MA 02115, *Undergraduate research participant.

We are working to establish whether highly purified humic acids (HA) from different plant and soil sources are similar or different(1,2). Soil organic matter contains HA-mineral complexes that help to stabilize and immobilize HAs so they can perform their water retention and other functions. Few studies of humic substance-mineral interactions contain sufficient data to allow thermodynamic modelling. In this study, interactions of dissolved aqueous HAs isolated from a German peat (GHA), an Irish peat (IHA), an unpolluted New Hampshire bog soil (NHA) and the free-living marine alga Pilayella littoralis (PHA) with the common smectic clay kaolinite were investigated. The room temperature optical absorbance of each aqueous HA at 320 nm is a linear function up to at least 50 mg HA/L and is independent of pH = 3-7. The calibration plot for each HA can be used to measure the mg dissolved HA/L in equilibrium with a known amount of the kaolinite adsorbent to generate an adsorption isotherm. Isotherms were measured for each HA at seven temperatures in the range 5.0 - 35.0oC and each isotherm was repeated three times to give average data that fit the Langmuir model with two sequential adsorption steps. The first step is monolayer formation and the second is adsorption of HA on HA. Most of the observed adsorption steps are exothermic and result in an entropy increase. The adsorption enthalpies and entropies fit a single linear correlation, indicating a common underlying mechanism with dehydration of the kaolinite surface and the HAs as important steps.

1. E. A. Ghabbour, G. Davies, A. Fataftah, N. K. Ghali, M. E. Goodwillie, S. A. Jansen, N. A. Smith, J. Phys. Chem. 101B, 8468 (1997).
2. G. Davies, A. Fataftah, A. Cherkasskiy, E. A. Ghabbour, A. Radwan, S. A. Jansen, S. Kollar, M. D. Paciolla, L. T. Sein, Jr., W. Buermann, M. Balasubramanian, J. Budnick, B. Xing, J. Chem. Soc. Dalton Trans. 4047 (1997).



Baoshan Xing

University of Massachusetts, Amherst, MA 01003

Humic substances (HS) are ubiquitous in water, soils and sediments. They are also very reactive with organic chemicals and heavy metals. Partitioning has been considered as the sole mechanism for sorption of hydrophobic organic compounds (HOC) in HS (1), but this conclusion is challenged by recent research findings (2,3). The objective of this presentation is to report and discuss experimental evidence (e.g., sorption nonlinearity and competitive sorption) that is inconsistent with partitioning. Humic acids from various sources, peat and soil samples were tested with a number of HOC including toluene, naphthalene, chlorinated benzenes, trichloroethylene and some pesticides. Isotherms were constructed using a batch equilibration technique and wide concentration ranges (2.5 orders of magnitude or larger). Sorbent to solution ratios were adjusted to obtain 25 to 80% sorption. Structural analysis of HS was performed using solid-state CP/MAS 13C NMR. Competitive sorption experiments were conducted with pairs of solutes. All isotherms were nonlinear (i.e., the exponent N in the Freundlich equation was less than one) for nonpolar and polar compounds alike. These results indicate energy distribution of sorption sites in HS. The N values appeared to increase with increasing aromaticity and degree of condensation of HS. Nonlinearity also increased with contact time. Strong competition occurred for compounds with comparable molecular structure and size. Naturally occurring aromatic acids (e.g., vanillic) also competed with chlorinated benzenes or phenol and blocked sorption sites. Competitive sorption may increase mobility and bioavailability of HOC in soil. Sorption mechanisms in HS will be also discussed.

1. Chiou, C.T., In Reactions and Movement of Organic Chemicals in Soil, Sawhney, B.L., Brown, K., Eds.; Special Publication No. 22, SSSA, Madison, WI, 1989, pp. 1-29.
2. Xing, B. and Pignatello, J.J., Environ. Sci. Technol. 31, 792-799 (1997).
3. Weber, W.J. Jr. and Huang, H., Environ. Sci. Technol. 30, 880-888 (1996).

The Ability Of Microorganisms To Reduce Quinone Groups In Humic Substances

Durelle Scott,1 Diane McKnight,1 Derek Lovley,2 Betsy Harris,2 and Sarah Kolesar3

Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309
2Department of Microbiology, University of Massachusetts, Amherst, MA 01003
3Center for Environmental and Estuarine Studies, University of Maryland, Solomons, MD

Recently, Lovley et al. (1996) found that humic substances can act as the sole electron acceptor in the anoxic oxidation of acetate by Geobacter metallireducens(1). We have determined that quinone groups are the reducible moiety by measuring the organic radicals within humic substances using electron spin resonance(2). Humic substances from a variety of environments, including soils, marine sediments and Antarctic lakes, all have an electron accepting capacity that is dependent on their quinone content. Our results indicate that quinone moieties are the primary electron accepting group, and that humic substances in any anoxic environment can participate in microbial reduction of organic molecules.

1. Lovley, D., Coates, J., Blunt-Harris, E., Phillips, E., and Woodward, J., Nature, 382, 445-448 (1996).
2. Scott, D., Quinone Moieties Act as Electron Acceptors in Reduction of Humic Substances by Fe(III)-Reducing Microorganisms. M. S. Thesis, University of Colorado, 1997.


Generation of Free Radicals by HA: Implications for Biological Activity

Mark D. Paciolla,1 Santha Kolla,1 Lawrence T. Sein, Jr.,1 James M. Varnum,2 Damien L. Malfara,1 Geoffrey Davies,3 Elham Ghabbour3 and Susan A. Jansen1

Temple University, Philadelphia, PA 19122
2Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107
3Department of Chemistry, Northeastern University, Boston MA 02115

The discovery of humic acid (HA) in live plants raises many important questions concerning the origin and function of HA in living systems. The close structural relationship of HA to lignins suggests related but unique functions. Lignins are highly functional plant structural materials. Other plant derived, lignin-like and phenolic materials provide the plant with protection against free radical and oxidation damage. All assist in metal uptake regulation and water retention. This work is directed at analysis of free radical systems intrinsic to HA, and the free radical processes induced by HA. The free radical involved, a quinoid that is thermally or photochemically induced, is generated by at least two distinct processes that both yield OH.. Since HA is insoluble from pH 1-8, free radical induction and hydroxyl radical formation are likely to be surface processes. Studies of HA interaction with supercoiled DNA demonstrate that the radical population is significant and active enough to effect DNA cleavage. Internal quenching of OH. produced directly from HA, and from reactions of peroxide with HA, is dependent on the surface concentration of quinoid radical species.

1. Kappock, T. J., Caradonna, J. P. Chem. Rev., 96, 26159-2756 (1996)
2. Rao, N. R., Cederbaum, A. I., Free Radical Biol. and Medicine, , 22, 439 (1997)
3. Gould, S. J., Melville, C. R., Tet. Lett., , 38, 1473 (1997)
4. Murphy, W. S, Neville, P., Ferguson, G., Tet. Lett, , 37, 7615 (1996)
5. Molina, P., Stoppani, A. O., Biochem. Pharmacol,., 51, 273 (1995)
6. Morimoto, H., Kikuchi, S., Nagaoka, S., Biochim. Biophys. Acta, , 1157, 313 (1993).

Humic Acid as a Reactive Substrate for Alkylation

Santha Kolla,1 Lawrence T. Sein, Jr.,1 Mark D. Paciolla,1 John Moyer,1 Daman Walia,2 Harley Heaton2 and Susan A. Jansen1

Department of Chemistry, Temple University, Philadelphia, PA 19122
2Arctech Inc, 14100 Park Meadow Drive. Chantilly, VA 20151

In this work we demonstrate that humic acid can serve as a reactive substrate toward alkylation. As a solid multifunctional homogeneous material, humic acids can be used to react with and immobilize a variety of organic moieties. In this work, methylation was achieved by reacting humic acid with methyl iodide utilizing two unique experimental approaches. One approach is based on the Williamson ether synthesis, the other on coupling radical species. 13C labeling studies clearly indicate methylation of humic acid and suggest certain functional group substitutions. Methylated humic acids remain insoluble in alcohols and aqueous media from pH 2-10.

1. (a) H. R. Schulten, M. Schnitzer, Naturwissenschaften, , 82, 487 (1995); Soil Sci., 162, 115 (1997); (b) N. Senesi, G. Calderoni, Org. Geochem., 13, 1145 (1988); (c) N. Senesi, G. Sposito, G.R. Bradford, K.M. Holtzlaw, Water, Air, Soil Pollut., 53, 409 (1991).
2. (a) C. Steelink, M. Mikita, K. Thorn, Aquat. Terr. Humic Mater., 83 (1981); (b) M. Schnitzer, S. Skinner, Soil Sci,., 108, 383 (1969).


James J. Alberts,1 Monika Takács1 and Dag Olav Andersen2

University of Georgia Marine Institute, Sapelo Island, GA 31327
2Agder College, 4604 Kristiansand, Norway

Highly colored lakes in Norway have suffered from acidification of their watersheds over several tens of years, often leading to low pH values which effectively sterilize the lake to most invertebrates. To reverse this acidification, the government of Norway began extensive "liming" programs in various waters. However, the effect of this liming on the natural organic matter (NOM), which gives these waters their intense color and serves as a potential nutrient source, is not well understood. Therefore, NOM was isolated by reverse osmosis (RO) from two inlet streams and the outlet of a lake in southern Norway, which has been receiving liming treatments since the mid-1980’s. Laboratory studies of the isolates indicate that the molecular size distributions of this organic matter shift to larger molecular size with increasing pH and that the uv-visible spectral absorption coefficient of the NOM differs with organic size fraction and pH. In addition, the C:N ratios of the size fractions differ, with smaller size fractions of NOM being enriched in N relative to larger fractions. Examination of the NOM in the lake water by high performance size exclusion chromatography shows that processes similar to those observed in the laboratory are also occurring in the lake proper. In addition, larger NOM size fractions are being removed from the water by processes in the lake, probably as a result of the liming activities. The in-lake processes are also almost doubling the nitrogen content of the organic matter at the outlet of the lake, where the pH has increased by about 2 pH units to around 6.5. Thus, liming of this lake has effectively increased the pH of the lake waters to levels that comfortably sustain invertebrate and vertebrate organisms and increase the nitrogen levels of the NOM, which acts to enhance their utilization as a nitrogen source by microbial communities(1).

1. Filip, Z., Alberts, J. J., Sci. Total Environ., 144, 121 (1994).



T.A. Knauf

Earthgreen Products Inc., 8222 Douglas Ave., Suite 200, Dallas, TX 75225

Humic acids can enhance germination, seedling growth, root and shoot development, nutrient uptake and plant vigor (1-3). Accordingly, humic substances are widely used as soil amendments and as aids in commercial plant and crop production. However, most agricultural, horticultural, and turf applications of humates and humic acids are in the form of granular or liquid humic substances. The production of a consistent, economical, and efficacious water-dispersible humic acid product would be of major importance to those seeking a more convenient source of humic acid for drench, drip irrigation, and foliar applications. Early in 1996, Earthgreen Products Inc. formulated a new humic acid product extracted from Menefee Humate®. Early test results were promising and in April, 1997, commercial production started with a small pilot unit at the Menefee Mining Corporation at Cuba, NM. The material is designated "ESP-50". ESP-50 is a water-dispersible extract from Menefee Humate® with 50% humic acid and a pH of 6.2. Field research on this product began immediately and involved major U.S. agricultural and ornamental crops. State universities, private research facilities, and commercial cooperators studied the effect of various ESP-50 rates, timings and application methods on plant growth and development. Results from replicated trials on soybeans, field corn, sweet corn, cotton, and tomatoes indicate significant yield responses with certain rates and timings of drenches and foliars with ESP-50. Results on ornamentals indicate marked enhancement of plant vigor with ESP-50™ and significant synergism with certain fungicides has been observed.

1. Chen, Y.; Aviad, T. Effects of humic substances on plant growth. In Humic Substances in Soil and Crop Sciences: Selected Readings. MacCarthy, P; Clapp, C. E.; Malcolm, R. L.; Bloom, P. R., Eds., American Society of Agronomy, Madison, Wisconsin, 1990, pp. 161-186.
2. Castro, B. F., et al., Proc. Florida Horticult. Soc., 101, 350-35 (1988).
3. David, P. P., et al., J. Plant Nutrition,. 17, 173-184 (1994).



C. E. Clapp,1 V. W. Cline,1 M. H. B. Hayes2 and R. Liu1

USDA-ARS, University of Minnesota, St. Paul, MN

University of Birmingham, Birmingham, UK

Humic substances (HS) are plant growth stimulating agents that have been applied in agricultural and horticultural management in recent years. However, detailed mechanisms of how these materials work in plants are still not well understood, due to complex HS structures in nature. There are many reports of HS roles in promoting plant biomass, stimulation of root, shoot, and flowering growth, and even direct effects on crop productivity and increases in crop yields. The HS consist of humic acids, fulvic acids and humin. They can be extracted from many natural sources such as peat, soil, and Leonardite ore. Municipal yard wastes, sewage sludge and composts also could be sources of these materials. Application of the humics in golf course and sports turf management has recently been re-discovered. Due to major environmental concerns, it is becoming a popular practice to use these materials as soil amendments. They not only increase fertilizer efficiency and promote plant growth, but can reduce the potential of groundwater contamination. Plant growth research involving HS at the University of Minnesota in the Departments of Horticulture and Soil, Water and Climate has centered on growth chamber, greenhouse, and golf green experiments, Both basic and practical research components are underway to investigate the 'how and why' of HS interactions with plant and soil ecosystems. Humic substances from several commercial and natural sources have been tested with Creeping Bentgrass (Agrostis palustris cv. Providence) in growth chamber microsystems experiments. The setup consisted of micro tissue culture plates filled with sand and a filter paper wick to provide water and nutrients from a constant head plastic tray. Preliminary results indicated that the system was sensitive to nutrient and HS dynamics. Specific HS samples gave significant increases in grass root and shoot growth over fertilizer controls. Larger scale greenhouse experiments in simulated golf green mixes of sand or sand/peat showed several HS products to be effective and productive turfgrass growth promoters. The impact of recent use of HS on horticultural and agricultural utilization will be discussed.



Daman Walia and Amjad Fataftah

Arctech, Inc., Chantilly, VA 20151

In December, 1997, most of the nations signed a treaty in Kyoto, Japan to reduce greenhouse CO2 gas emissions by 6-8% between the years 2010 and 2012. This worldwide consensus is the result of mounting scientific evidence of potential impact of continuing excessive emission of greenhouse gases on our global climate and adverse consequences thereof. The treaty requires aggressive strategies to curb CO2 emissions from the use of fossil fuels, especially coal. The primary dilemma is that it would require high costs and thus potential downturn of ongoing rapid growth to foster free market economies. ARCTECH’s novel approach of bioconversion of coal into humic acid and clean fuels as an alternative to coal combustion is one viable alternative to achieve over 50% reduction in CO2 emission and propel significant economic growth. This approach is based upon the versatile applications of humic acid for replenishing our depleted soil, cleaning the environment and thus sequestering carbon on our planet. An overall strategy and various ongoing ARCTECH projects will be discussed to accomplish this objective.

1. Walia, D., Srivastava, K., US Patent 5, 670, 345 (1997).
2. Walia, D., Heaton, H., Stashick, J. J., US Patent 5, 538, 530 (1996).
3. Walia, D., Sanjay, H. G., Srivastava, K., US Patent in process.