The presence of nitrate and other redox-active anionic contaminants in terrestrial ecosystems poses a significant risk to humans and other forms of life on Earth. The purpose of the present study was to test a potential in situ system, using poly-(D) glucosamine (chitosan) adsorbed to mineral surfaces under redox-active conditions in order to degrade nitrate to lower oxidation states. Chitosan is a linear polysaccharide derived from the chitin found in the shells of shrimp and other shellfish. Five different loadings of chitosan (0, 0.075, 0.25, 0.50, and 1.0 g/L; labeled C0, C1, C2, C3, and C4, respectively) were adsorbed to ferruginous smectite (SWa-1) to form chitosan-SWa-1 composites (CSC) in the pH range 5.8–4. The CSC was then reduced by Na2S2O4 in a citrate-bicarbonate buffered dispersion and washed free of excess salts under inert-atmosphere conditions. Upon addition of the nitrate, the solution pH remained slightly acidic, ranging from 5.5 to 4.7. Samples were analyzed for Fe(II) content, reacted with a NaNO3 solution, and then re-analyzed for structural Fe(II) content. Supernatant solutions were analyzed for nitrate, nitrite, and ammonium. In samples C1 to C4, extensive concentrations of nitrite were observed in the supernatants with a corresponding increase in the reoxidation of structural Fe(II), proving that a coupled redox reaction had occurred between the nitrate and the structural Fe in the clay mineral. The most efficient loading, defined as the largest percentage of adsorbed nitrate reduced to nitrite, occurred in sample C1. The total amount of nitrate reduced and Fe(II) reoxidized followed the trend 0 = C0 < C2 < C3 < C4 ≈ C1. Chitosan showed the potential to reverse the surface charge of constituent clay minerals, thereby enabling the CSC to remove nitrate anions from aqueous mineral systems via redox reactions with structural Fe(II) in clay minerals.

Crop-livestock integration has demonstrated that cover crops can be terminated using livestock grazing with minimal negative impacts on soil health, however, provides little information on system-level approaches that mutually benefit soil health and both crop and livestock production. Therefore, the objective of this research was to examine the effects of cover crop mixtures on biomass production, quality and the potential for nitrate toxicity on a dryland wheat-cover crop rotation. This research was conducted at the Montana State University-Northern Agricultural Research Center near Havre, MT (48°29′N, −109°48′W) from 2012 to 2019. This experiment was conducted as a randomized-complete-block design, where 29 individual species were utilized in 15 different cover crop mixtures in a wheat-cover crop rotation. Cover crop mixtures were classified into four treatment groups, including (1) cool-season species, (2) warm-season species dominant, (3) cool and warm-season species mixture (mid-season), and (4) a barley (Hordeum vulgare) control. All cover crop mixtures were terminated at anthesis of cool-season cereal species to avoid volunteer cereal grains in the following wheat crop. At the time of cover crop termination, dry matter forage production was estimated and analyzed for crude protein, total digestible nutrients and nitrates as indicators of forage quality. All mixtures containing oats (Avena sativa) had greater (P ⩽ 0.03) biomass production than other mixtures within their respective treatment groups (cool- and mid-season). Forage biomass was influenced by cover crop treatment group, with the barley producing the greatest (P < 0.01) amount of forage biomass when compared to cool-, mid- and warm-season cover crop treatments. Total digestible nutrients were greater (P < 0.01) in the barley control compared to the cool- and mid-season treatment groups. Crude protein was greatest in the warm-season treatment group (P < 0.01) compared to the barley control, cool- and mid-season treatment groups. The barley control produced fewer nitrates (P ⩽ 0.05) than the cool-, mid- and warm-season treatment groups; however, all cover crop mixtures produced nitrates at levels unsafe for livestock consumption at least one year of the study. The relatively high and variable nitrate levels of all cover crop mixtures across years in this study suggest that forage should be tested for nitrates before grazing. In conclusion, our research suggests that in a dryland wheat-cover crop rotation that requires early-July termination, cool-season cover crop mixtures are the most suitable forage source for livestock grazing most years.

Foliar sprays of 2,4-D, dicamba, and triclopyr were applied to vegetative annual goldeneye at 0.56, 1.1, and 2.2 kg ai ha-1. Mortality was 47% and 64% after treatment with triclopyr and 2,4-D at 2.2 kg ha-1, respectively. Mortality was less than 30% at lower rates. Mortality was 54%, 93%, and 100% after treatment with dicamba at 0.56, 1.1, and 2.2 kg ha-1, respectively. Foliar cover of tobosagrass increased 119% and 92% on plots treated with dicamba at 1.1 and 2.2 kg ha-1, respectively. Herbicide treatment did not affect nitrate concentration (0.03% to 0.05%) in treated plants.

Toxicological investigations were conducted on galenia [Galenia pubescens (Eckl. and Zeyh.) Druce], an introduced species of the family Aizoaceae. One lot of field-grown galenia assayed 2.5% nitrate (as KNO3) and 6.1% soluble oxalates. Three sheep were acutely poisoned after they were gavaged with this plant. Galenia grown in nutrient solution assayed 6% nitrate and 11.3% soluble oxalates. Chicks fed this material died of nitrate and oxalate poisoning. Galenia may accumulate toxic levels of both oxalates and nitrates and thus should be classed as a poisonous plant that would be considered hazardous to humans and livestock.

We estimate adults' willingness to pay (WTP) to reduce health risks to their own or other families' infants to test for altruism. A conjoint analysis of adults paying for bottled water found marginal WTP for reduction in risk of shock, brain damage, and mortality in the cash treatment of $2, $3.70, and $9.43, respectively. In the hypothetical market these amounts were $14, $26, and $66, indicating substantial hypothetical bias, although not unexpected due to the topic of infant health. Statistical tests confirm a high degree of altruism in our WTP results, and altruism held even when real money was involved.

Firestone (2014) asserted evidence for numerous (23) nearby (d < 300 pc) supernovae (SNe) within the Middle and Late Pleistocene. If true, this would have strong implications for the irradiation of the Earth; at this rate, the mass extinction level events due to SNe would be more frequent than 100 Myr. However, there are numerous errors in the application of past research. The paper overestimates likely nitrate and 14C production from moderately nearby SNe by about four orders of magnitude. Moreover, the results are based on wrongly selected (obsolete) nitrate and 14C datasets. The use of correct and up-to-date datasets does not confirm the claimed results. The claims in the paper are invalid.

Plasma thiocyanate has been reported to be high among cassava-eating populations such as that in Nigeria because of the cyanide content of cassava. Thiocyanate, which is secreted into the stomach contents of animals, has been demonstrated to catalyse the formation of nitrosamines (potent carcinogens) in the stomach from secondary amines and nitrite. The main source of the nitrite precursor in this environment is vegetables, primarily eaten as the chief supplier of proteins. The present study attempts to analyse the levels of nitrate and nitrite in vegetables commonly grown and consumed in Delta State, Nigeria. The nitrate and nitrite contents in green vegetable (Amaranthus spp.), bitter leaf (Vernonia amygdalina), pumpkin (Telfaria occidentalis) and water leaf (Talinum triangulare) grown in different localities of the state were determined by standard analytical procedures. The results show that those vegetables grown in the industrialised urban centres of the state had higher nitrate (223 (sd 71) mg/kg dry weight; P<0·05) and nitrite (12·6 (sd 1·7) mg/kg dry weight; P>0·05) levels when compared with the same species (188 (sd 77) mg nitrate/kg dry weight and 10·9 (sd 1·1) mg nitrite/kg dry weight) cultivated in less industrialised suburbs. We conclude that frequent consumption of such vegetables whose nitrate and nitrite contents are high by cassava-eating individuals might put them at risk of developing stomach cancer and other possible results of nitrate and/or nitrite toxicity. In order to avoid an outbreak in our communities, appropriate agencies should monitor and regulate the release of chemicals into the environment. In the meantime, the cultivation and consumption of vegetables grown in industrialised areas of the state should be discouraged.

In the UK the poultry industry has a good record with regard to surface water contamination and has been responsible for only a small proportion of the total pollution incidents attributable to agriculture. Guidance is provided to farmers by a Code of Good Agricultural Practice for the Protection of Water. Because poultry manures have high concentrations of total nitrogen, with much of this in soluble form, the pollution of ground water with nitrates is a more serious problem. A voluntary Pilot Nitrate Scheme has been introduced in some parts of the UK which controls the quantities of animal waste applied to the land and also the timing of waste application. Linked to the scheme is a comprehensive programme of scientific monitoring. The broad requirements of the European Community Nitrate Directive are described. In the case of air pollution due to odours, poultry farms were reported to be responsible for 17% of complaints attributed to agriculture. Where appropriate, legislative means exist to reduce the nuisance and a Code of Good Agricultural Practice for the Protection of Air has been published. Some implications for poultry production in the future are considered.

L'expérimentation, menée au cours d'un cycle annuel sur deux secteurs différents de la rivière Charente à l'aval d'Angoulème, a pour objectif de quantifier le taux de dénitrification pour les besoins d'un modèle hydrologique nitrates.La méthode de blocage du stade final de la réaction de dénitrification à l'acétylène a permis le dosage du protoxyded'azote à partir de cloches à sédiment et d'un conteneur immergé en pleine eau.Les résultats montrent que, si ce phénomène n'a pas lieu dans la tranche d'eau, la vitesse de dénitrification à l'interfaceeau-sédiment, facteur K exprimé en mg de nitrates dénitrifiés par m2 par jour, peut être considérée comme constante et indépendante des variations en température, en teneurs en nitrates et oxygène dissous de l'interface.Sur un cycle annuel, en l'absence d'influence marquée des paramètres environnementaux, le taux moyen de dénitrification dans la rivière Charente est de 682 mg de NO3- /m2/ j.La comparaison des mesures obtenues par cette méthode à celles évaluées par le calcul (bilan azoté) montre qu'il estpréférable d'estimer le taux de dénitrification par dosage direct plutôt qu'à partir de l'analyse des formes de l'azote(disparition du NO3 - ou défaut du bilan).

A method for measuring NH3 colorimetrically by Nesslerization without distillation is proposed. Precipitation of CaCO3 is prevented by adding Na salicylate, which chelates the Ca2+, but not the Hg2+ of Nessler's reagent. NO3 - can be measured in the same way after reduction with TiCl3. Precision and accuracy are those of a colorimetric method ; the sensitivity is somewhat lower than with the indophenol-blue method using phenol, but about the same as when using salicylate.

Contamination of ground water from agricultural sources has been documented in a majority of the contiguous United States. In this study, we examine the potential for voluntary adoption of management practices that reduce risk of ground water contamination and discuss how f arm operators' attitudes regarding the environment might affect the success of voluntary programs. Farmers' behavior and attitudes in Rockingham County, Virginia, and Big Spring Basin, Iowa, reveal that both groups consider the ground water issue to be a serious problem to which they are contributing. This awareness is a significant first step in prompting consideration of management practices that reduce the threat to ground water quality. We also found that the “worst offenders”—that is, farmers applying nitrogen well above agronomic recommendations-were those with the least concern about the problem. If major shifts in farming practices are to occur voluntarily, major incentives or disincentives are needed. Even though the concern about ground water quality is high, the documented risks perceived by farmers are not strongly convincing. The economic incentives for change are questionable at best. Voluntary adoption of best management practices is only one of several policy options. Ultimately, policies designed to reduce ground water contamination may need a mix of strategies, including economic incentives and disincentives, zoning and land use restrictions, environmental regulations, and bans on agricultural chemicals.

L'établissement du bilan des entrées et sorties de nitrates dans quelques lacs de gravières ainsi que la mesure directe de la dénitrification par émission de N2O (méthode à l'acétylène) ont permis d'évaluer l'activité dépolluante de ces lacs vis-à-vis de la nappe phréatique de la Garonne.L'activité dénitrifiante la plus élevée a été mesurée dans un lac ancien, non colmaté, artificiellement eutrophisé. Par contre, les gravières anciennes colmatées sont sans effet.Des surfaces considérables de plan d'eau sont nécessaires afin d'épurer des débits suffisants en vue de l'alimentation des captages d'eau potable.

La disparition des nitrates d'une nappe superficielle circulant sous un bois d'aulnes et la mesure directe de l'émission de N2O (méthode à l'acétylène) montrent la capacité de ce type de végétation à améliorer la qualité des eaux souterraines. L'activité de ce système semble atteindre une efficacité plus élevée que celle des eaux de surface en raison de la conjonction de facteurs favorables : fourniture de carbone organique dégradable, conditions d'anaérobiose, transport de masse des nitrates.Etant donné l'efficacité du processus, il est suggéré un réaménagement en aulnaie des lacs de gravières situés en amont des captages d'eau potable, afin d'en améliorer la qualité des eaux.