NovaSil (NS) clay, a common anti-caking agent in animal feeds, has been shown to sorb aflatoxins in the GI tract and diminish their bioavailability and adverse effects in short-term animal studies. Based on this evidence, it is hypothesized that clay-based enterosorption of aflatoxins may be a useful strategy for the prevention of aflatoxicosis in human populations. However, the potential toxicity of long-term dietary exposure to NS has not been determined. In this research, 5-6-week-old male and female Sprague-Dawley rats were fed rations containing 0, 0.25, 0.5, 1.0, or 2.0% (w/w) levels of NS for 28 weeks. Analysis of the NS showed negligible levels of dioxin and furan contaminants. Total feed consumption, cumulative feed consumption, body weight, total body weight gain, feed conversion efficiency, cumulative feed conversion efficiency, and relative organ weights were unaffected in either sex at the doses tested. No NS-dependent differences in relative organ weights or gross or histopathological changes were observed. Analysis of hematological parameters, clinical chemistry, and selected vitamin and mineral levels revealed isolated significant differences between some treatments and control groups (mean corpuscular hemoglobin, serum Ca, serum vitamin A, and serum Fe). However, the differences observed in each case were not dose-dependent. These results suggest that dietary inclusion of NS at levels as high as 2.0% (w/w) does not result in overt toxicity. These findings (as well as others) support the use of NS clay for dietary intervention studies in human populations at high risk for aflatoxicosis.

Sorbent materials consisting of organoclay immobilized onto the surface of a solid support were evaluated for use in pentachlorophenol (PCP) and polycyclic aromatic hydrocarbon (PAH) remediation of groundwater at a creosote-contaminated Superfund site. Cetylpyridinium-exchanged low pH montmorillonite clay (CP-LPHM) was bonded to either sand (CP-LPHM/sand) or granular activated carbon (GAC) (CP-LPHM/GAC) using the free acid form of carboxymethylcellulose as an adhesive. Effluent from an oil–water separator was eluted through equal bed volumes of composite (4 g 3:2 CP-LPHM/GAC or 13 g CP-LPHM/sand), affinity-extracted, and quantitatively analyzed by GC/MS. PCP, naphthalene, fluorene, phenanthrene, pyrene, and total PAHs were initially reduced by both CP-LPHM/GAC (⩾99%, 61%, 99%, ⩾99%, 97%, and 94%, respectively) and CP-LPHM/sand (90%, 70%, 94%, 95%, 93%, and 86%, respectively). Complete breakthrough of naphthalene occurred after approximately 15 h of elution through 3:2 CP-LPHM/GAC and 22 h through CP-LPHM/sand. PCP showed complete breakthrough following 18 h of elution through 3:2 CP-LPHM/GAC and 26 h through CP-LPHM/sand. However, 50% breakthrough was not attained for higher molecular weight PAHs, as fluoranthene, pyrene, benzo[a]anthracene, and chrysene continued to be greatly reduced with both 3:2 CP-LPHM/GAC (98%, 95%, 94%, and 95%, respectively) and CP-LPHM/sand (75%, 73%, 76%, and 78%, respectively) after 48 h of continuous elution. Results confirm prior studies, indicating that these organoclay-containing composites have a high capacity for contaminants found in wood preserving waste. Further, results suggest that the inclusion of CP-LPHM may be useful as part of an effective strategy for groundwater remediation of high concentrations of PCP and PAHs, in particular high molecular weight and carcinogenic PAHs.

Previous methods for the control of zearalenone (ZEN)-induced hyperestrogenism in animals have proven largely ineffective. The main objective in this study was to identify an enterosorbent that decreases the dietary bioavailability, and subsequent estrogenic effects, of ZEN. Initial in vitro screenings in aqueous solution (4 microg ZEN/ml) indicated that an activated carbon (AC) was the most efficient sorbent (99%), followed by a combination of 2 parts AC plus 3 parts HEC (hectorite) (69%), cetylpyridinium-exchanged low-pH montmorillonite (CP-LPHM) clay (58%), hexadecyltrimethylammonium-exchanged low-pH montmorillonite (HDTMA-LPHM) clay (54%), and HEC alone (28%). Results from the adult hydra bioassay suggested that the addition of either AC or HEC effectively decreased the effects of ZEN on Hydra attenuata without toxicity, as was observed with the use of either CP-LPHM or HDTMA-LPHM. Based on these results, AC, HEC, and 2AC:3HEC were evaluated in prepubertal mice. At a dietary inclusion level of 0.8% (w/w), AC alone significantly protected mice against the estrogenic effects induced by 35 mg ZEN/kg feed. Inclusion of 1.2% HEC with the 0.8% AC showed no additional protection; whereas 1.2% HEC alone failed to decrease the estrogenic effects. Ground flaxseed (25% w/w) in the diet also elicited protection, but to a lesser extent. Preliminary studies suggested that three similar carbons failed to decrease ZEN bioavailability. These findings suggest that the AC used in this study may be efficacious as an enterosorbent in animals consuming ZEN-contaminated diets. However, further studies are needed to evaluate the binding specificity, as well as the safety of chronic exposure.

Silicate clays are frequently added to animal feeds to bind and reduce the bioavailability of mycotoxins in the gastrointestinal tract. However, the bioavailability of trace metals in these clay feed additives has not been thoroughly investigated. Clays that act nonselectively may interact with nutrients, minerals, and other feedborne chemicals to pose significant hidden risks. In this study, a calcium montmorillonite clay (Novasil Plus, NSP) commonly used as an enterosorbent for aflatoxins and a sodium montmorillonite clay (Swy-2) (Source Clay Minerals Repository, Columbia, MO) were examined. Clays were supplemented in the balanced diet of Sprague-Dawley rats during pregnancy at a level of 2% (w/w). Evaluations of toxicity were performed on gestation d 16 and included maternal body weights, maternal feed intakes, litter weights, and embryonic resorptions. Liver, kidneys, tibia, brain, uterus, pooled placentas, and pooled embryonic mass were collected and weighed. Tissues were lyophilized and neutron activation analysis (NAA) was performed. Elements considered by NAA included Al, Ba, Br, Ca, Ce, Co, Cr, Cs, Cu, Dy, Eu, Fe, Hf, K, La, Lu, Mg, Mn, Na, Nd, Ni, Rb, S, Sb, Sc, Se, Sm, Sr, Ta, Tb, Te, Th, Ti, Tl, U, V, Yb, Zn, and Zr. Inductively coupled plasma–mass spectroscopy further confirmed that Al was below detection limits (<0.5 ppm) in the brain. Animals supplemented with either NSP or Swy-2 were similar to controls with respect to toxicity evaluations and metal analysis, with the exception of decreased brain Rb following clay supplementation. Overall, the results of this study suggest that neither NSP nor Swy-2, at relatively high dietary concentrations, influences mineral uptake or utilization in the pregnant rat.

Complex mixtures of hazardous chemicals such as polycyclic aromatic hydrocarbons (PAHs) in contaminated soil and groundwater can have severe and long-lasting effects on health. The evidence that these contaminants can cause adverse health effects in animals and humans is rapidly expanding. The frequent and wide-spread occurrence of PAHs in groundwater makes appropriate intervention strategies for their remediation highly desirable. The core objective of this research was to assess the ability of a clay-based composite to sorb and remove toxic contaminants from groundwater at a wood-preserving chemical waste site. Treatment efficiencies were evaluated using either effluent from an oil–water separator (OWS) or a bioreactor (B2). The effluent water from these units was passed through fixed bed columns containing either an organoclay composite or granular activated carbon. The sorbent columns were placed in-line using existing sampling ports at the effluent of the OWS or B2. Individual one-liter samples of treated and untreated effluent were collected in Kimax bottles over the course of 78 h (total of 50 samples). Subsequently each sample was extracted by solid phase extraction methodology, and pentachlorophenol (PCP) and PAH concentrations were quantitated via GC/MS. Columns containing porous organoclay composite, i.e. sand-immobilized cetylpyridinium–exchanged low-pH montmorillonite clay (CP/LPHM), were shown to reduce the contaminant load from the OWS effluent stream by 97%. The concentrations of benzo[a]pyrene (BaP) and PCP were considerably reduced (i.e. >99%). An effluent stream from the bioreactor was also filtered through columns packed with composite or an equivalent amount of GAC. Although the composite reduced the majority of contaminants (including BaP and PCP), it was less effective in diminishing the levels of lower ring versus higher ring PAHs. Conversely, GAC was more effective in removing the lower ring PAHs, except for naphthalene and PCP. The effectiveness of sorption of PCP from the OWS effluent by the composite was confirmed using a PCP-sensitive adult hydra bioassay previously described in our laboratory. The findings of this initial study have delineated differences between CP/LPHM and GAC for groundwater remediation, and suggest that GAC (instead of sand) as the solid support for organoclay may be more effective for the treatment of contaminated groundwater under field conditions than GAC or CP/LPHM alone. Further work is ongoing to confirm this conclusion.

ABSTRACT We previously characterized Tri1 , a gene required for hydroxylation of the C-8 position during trichothecene mycotoxin biosynthesis in Fusarium sporotrichioides NRRL 3299. Sequence analysis of the region surrounding Tri1 revealed a gene, named Tri16 , which could encode an acyltransferase. Unlike the wild-type parent strain NRRL 3299, which accumulates primarily T-2 toxin along with low levels of diacetoxyscirpenol (DAS) and neosolaniol (NEO) and trace amounts of 8-propionyl-neosolaniol (P-NEO) and 8-isobutyryl-neosolaniol (B-NEO), mutants containing a disruption of Tri16 were blocked in the production of the three C-8 esterified compounds T-2 toxin, P-NEO, and B-NEO and accumulated the C-8-hydroxylated compound NEO along with secondary levels of DAS. These data indicate that Tri16 encodes an acyltransferase that catalyzes the formation of ester side groups at C-8 during trichothecene biosynthesis. We also report the presence of a Tri16 ortholog in Gibberella pulicaris R-6380 that is likely linked to a presumably inactive ortholog for Tri1 .

Offensive odors which evolve during the decomposition of swine waste have resulted in complaints from neighbors in agricultural areas. This study chronologically monitored the emissions of volatile fatty acids (VFAs) during composting to quantify the release of malodorous compounds. Swine waste/sawdust mixtures and sawdust controls were placed in 208 liter reactor vessels and constantly aerated over a 21-day period. Acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids were quantified in total collections of condensed water vapor and volatiles released from the vessels. Exit gasses were passed through water-cooled condensers, and condensate was collected every 12 hours. Composting conditions were shown to be adequate by measuring carbon to nitrogen ratios, pH, temperature, and moisture contents. The 21-day aerobic treatment decreased all VFAs in the swine waste mixtures by 61 to 100 percent, with a mean of 87 percent. Prior to peak gas volatilization, when the vessel contents attained peak composting temperatures, acetic acid was emitted in the greatest amounts, followed by butyric, propionic, valeric, isovaleric, and isobutyric acids in order of decreasing emissions. Following peak gas volatilization, butyric acid was released in the greatest amounts, followed by acetic, propionic, valeric, isovaleric, and isobutyric acids. The described condensation procedure was shown to be an effective method to quantify malodorous compounds emitted during the decomposition of livestock waste. In addition, aeration was an effective treatment to decrease VFAs and, therefore, odor potential resulting from their emissions.

Swine manure mixed with sawdust was composted in 205 L pilot-scale vessels. Four runs with a total of 22 vessel studies were made during 1998 and 1999. Composting was conducted, with either continuous or intermittent aeration supplied to each vessel, for 17 to 29 day. Temperatures, airflow, carbon dioxide production, oxygen uptake, and ammonia production were monitored. Material masses, moisture contents, pH, and various chemical concentrations were determined for initial and final samples. Further in the final two runs, condensate from the exhaust air stream from each vessel was collected using water-cooled condensers (40 cm, 15 degreesC) and weighed every 12 hours. Condensates and extracts from initial and final material samples were analyzed by, gas chromatograph with flame ionization detector for volatile fatty, acids (VFAs). The results indicated that airflow had a strong effect on emissions. Ammonia release showed a linear trend vs. total airflow, with about 50% reduction in ammonia occurring for a 75% reduction in airflow. Acetic, propionic, and butyric acid emissions were reduced by, 68%, 68%, and 33%, respectively, and isobutyric, isovaleric, and valeric acid emissions were increased by 151%, 8%, and 18% for a similar airflow reduction. Thus, there is potential for reduced odors with reduced airflow. Results also indicated that initial pH influenced onset of composting and the potential for odor release. For vessels with initial pH below 5.95, compost heating was Slow, and temperature and CO2 production patterns indicated gradual development of and shifts between, mesophilic and thermophilic bacterial activity. For vessels that started at higher pH values, development was much more rapid. These effects, combined with the fact that a significant majority of the VFAs initially, present were not emitted but were not present at the end of the runs (particularly in the higher pH vessels), indicated that high bacterial activity was important for reduction of odor potential.

Gas chromatographic analysis of volatile fatty acids (VFAs) in mixtures of swine manure and sawdust and in condensate samples of gasses emitted during composting of these mixtures was conducted. Two pilot-scale composting runs were conducted in a total of 11 vessels under either continuous or intermittent aeration Initial pH below 6 in two of the vessels corresponded to slower onset of composting and greater release of VFAs over extended periods. Otherwise, composting began rapidly, and VFA emissions took place primarily in the first four days of the process. In all the vessels, total emissions were less than 1% of the initial VFA contents of the material even though final values for these contents were reduced by 95 to 100%, except for the two low pH vessels where reductions ranged from 51 to 93%, and except for isobutyric acid where 90% reductions were typical. Intermittent aeration (at a total air flow reduction of 76%) reduced emissions of acetic, propionic and butyric acids by 68, 68 and 33% relative to continuous aeration, but isobutyric, isovaleric and valeric acid emissions were increased by 151, 8 and 17%, respectively Thus, composting, particularly when initial pH was greater than or equal to 6, rapidly destroyed odorous compounds while they were still in the mixtures, and, even though the odor potential is high, particularly for butyric and valeric acids, if seems that composting with low air flow aeration has the potential to reduce odor problems.