G. A. Wallace

Some modifications in trace metal toxicities and deficiencies in plants resulting from interactions with other elements and chelating agents‐‐the special case of iron

Abstract Whenever land becomes contaminated with trace metals, most always two or more of the trace metals are in excess simultaneously. Nearly all of the baseline studies of metal excesses, however, have been made with single metals, and such studies do not accurately reflect the critical response levels. Various critical points can shift due to interactions. Analytical data must be obtained for as many as 20 different elements and their differential distribution among various plant parts, including roots, must be known to gain even a partial understanding of the interactions. Positive and negative synergisms, competition, protection, and sequential additivity are observed among the interactions. The nature of interactions varies considerably with concentration levels, soil pH, soil texture, level of soluble Ca in soil, presence of salinity, differential distribution in soil of the metals present in toxic quantities, presence or absence of chelating agents, soil organic matter levels, and other factors. ...

Immunologic measurement of antithrombin III-heparin cofactor and α2macroglobulin in disseminated intravascular coagulation and hepatic failure coagulopathy

Abstract Antithrombin III (AT III) and α2Macroglobulin (α-2M) were measured immunologically in the plasma of five patients with Disseminated Intravascular Coagulation (DIC) and eight with severe hepatic failure. In DIC secondary to sepsis both AT III and α-2M levels fell to very low levels. When DIC was associated with hepatic failure or with aspirin overdosage, α-2M levels remained near normal while AT III levels were low. In hepatic failure without associated DIC, α-2M levels remained elevated while AT III was found to be extremely low. The significance of these findings is discussed.

Purification of canine antithrombin III-heparin cofactor using affinity chromatography

Canine antithrombin III-heparin cofactor has been purified utilizing affinity chromatography with purified heparin as the ligand. The procedure is rapid and produces 100% yields of highly purified inhibitor. The inhibitor is a protein of molecular weight 77,000 daltons and possesses both heparin cofactor and progressive antithrombin activity. The inhibitor is a single chain polypeptide with a molecular weight of 77,000 daltons.

Effects of soil conditioners on emergence and growth of tomato, cotton, and lettuce seedlings

We grew tomato, cotton, and lettuce seedlings in containers in a glasshouse in various soils with different combinations of a polyacrylamide and a polysaccharide as soil conditioners. In some tests all soil conditioners were applied in solution, and in other tests part was applied in solution and part mixed dry into soil. The conditioners increased rate of emergence and dry weights of seedlings. Results were similar to those for Krilium over 30 years ago, but application rates for the soil conditioners used in this study were much smaller.

Control of soil erosion by polymeric soil conditioners

Polyacrylamide polymers are useful in forming water-stable aggregates in soil. They not only have a favorable effect on water infiltration in soil, but also decrease the erodibility of soil. To stabilize soil, the polymers are either mixed dry with soil and then subjected to a wetting, drying, and cultivation cycle or solutions containing polymers are applied to cultivated soil. Five diferent situations where polymers can decrease soil erosion are described. The first situation involves application to soil several centimeters deep to improve water penetration, so that there is less water runoff and less erosion. The second situation involves application to the surface up to a 2-cm depth of soil to create water-stable aggregates that resist erosion. The third situation involves spraying polymers in solution or applying dry material followed by wetting onto the soil surface, so that after drying the stable structure of the surface of soil will not easily break during rain storms, even thought water will penetrate, but with much running off. The soil may not be cultivated in this situation. The fourth situation involves applying polymers to soil via irrigation water to decrease soil erosion by the irrigation water, particularly from furrows. The fifth situation involves applying polymers to driveways and playing fields to decrease erosion of dust by wind. Tested rates of the polymers that inhibited erosion were much lower than those rates used for the product Krilium over 30 years ago.

EFFECTS OF EXCESS LEVELS OF A POLYMER AS A SOIL CONDITIONER ON YIELDS AND MINERAL NUTRITION OF PLANTS

We grew wheat (Triticum aestivum L. cv. INIA66R) and tomato (Lycopersicon esculentum Mill. cv. Tropic) in containers with a Xerorthents soil and with levels of an anionic soil conditioner far in excess of that needed for adequate stabilization of soil. The 1% rate increased the vegetative growth of plants over controls, and the 5% rate gave yields more nearly like controls. The anionic polymer decreased accumulation of the anions P and Si in all plants and decreased Mn and B in wheat only. The highest level of polymer also depressed accumulation of some of the macroelement cations. Both levels of polymer created 100% water-stable aggregates compared with only 38% in the control. The potential for toxicity of polyacrylamide soil conditioners is discussed.

Effect of polymeric soil conditioners on emergence of tomato seedlings

We conducted laboratory-glasshouse experiments with three different California soils known for severe crusting problems that hinder seed emergence. Some new polymers gave very effective control of the crusting problem, especially during the period of seedling emergence. One reason they are effective is that they are of higher molecular weight than polymers used in the past. Dry polymers were put into solution, and the solution was applied to soils as an anticrusting agent. Amounts needed are in the cost-effective range. Products tested included a natural polysaccharide (galactomannan)of molecular weight about 200 K daltons, a cationic polymer with molecular weight of about 5000 K daltons, and an anionic polymer with molecular weight of about 5000 to 12000 K daltons. Without polymers for the soils tested, there was very little seed emergence. In general, the most favorable results for seed emergence and water infiltration came from the anionic polymer, followed by the cationic polymer.

EFFECTS OF VERY LOW RATES OF SYNTHETIC SOIL CONDITIONERS ON SOILS

We applied new polymer soil conditioners to soil at rates in the range of 0.00025% and higher and observed improvement in water infiltration rates. Very low levels of polymers improved soil porosities, even though the rates were below the highest possible improvement. The results imply that degree of soil improvement may be matched with value of crop to be grown for maximum economic benefit.

Mechanisms involved in soil conditioning by polymers

We mixed three different soils (two sodic and calcareous and one very acid and serpentinelike) with polyanion and polycation polymers and with a polysaccharide in suspension and passed the flocculated particles through sieves of different size openings for measurement of components. Including (NH4)2SO4 in the suspension resulted in more compete flocculation with high pH soils and less with the acid soil. In contrast, with the polycation the (NH4)2SO4 resulted in less flocculation for all three soils. Liming the acid soil to pH 7 increased flocculation for both the polyanion and the polycation. The polyanion resulted in more flocculation on calcareous than on acid soil, and the reverse occurred for the polycation. These results indicate that the salt effect was that of bringing clay particles closely enough together so that several of them could be bound with a common polyanion. The binding then would occur many times with polyanions for each aggregate of clay particles. Ion bridging is an important phenomenon in which polyvalent cations may be shared with polymer and clay in the flocculation-aggregation process. The addition of a polysaccharide with the polyanion gives additive to synergistic responses, indicating that there is cross-linking between the two polymers. The total effect resembles a brush heap that secures stability for the flocculated particles.

A possible flaw in EPA's 1993 new sludge rule due to heavy metal interactions

Abstract The new 1993 sludge rule of the EPA (Environmental Protection Agency) sets (a) concentration limits for ten different heavy metals in sludge or sludge products that are sold or given away for use on soil, (b) cumulative loading rates for those ten metals in soil, (c) concentrations of the metals that can be considered as “clean” sludge, and (d) annual loading rates that must be met if the sludge is not “clean” but below the ceiling concentrations. The rule allows for widespread liberal use if the pathogen aspects are complied with. This encourages addition of organic carbon to soils which is urgently needed for soil improvement. The permissible levels of heavy metals may be too high, however, because EPA obviously did not fully consider the interactions which occur when 2–3–4–5 or more heavy metals are at high levels simultaneously especially after 40 years of use when decomposition releases some of the heavy metals. We have observed field situations where use of sludge composts for as many as 40...