Ppm In Soil Research Articles

Arsenic speciation in soil porewaters from the Ashanti Mine, Ghana

At the Ashanti Au mine in southwest Ghana, arsenopyrite constitutes an important part of the hypogene ore assemblage, often hosting significant concentrations of Au. The oxidation of arsenopyrite either through lateritic weathering or during mineral processing releases As into the environment. The speciation of As in soil porewaters both from uncontaminated soils and those overlain by mine waste has been assessed. In aerobic soils overlying, weathered Au As mineralization in the bedrock, As was present in concentrations of 189–1025 ppm in soil and porewater concentrations ranged from 86.2 to 557 μg l −1. Arsenic in these waters was found to be largely present as arsenate (approximately 78–95% of the total As) with arsenite, monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA) also present. Where arsenite concentrations are greater than arsenate, no organoarsenical species were observed. In the uncontaminated soils overlying unmineralized bedrock, background As concentrations were in the range of 12.5–20.2 ppm and porewater concentrations ranged from 11.2 to 20 μg l −1. In these porewaters arsenate was the dominant species. No organoarsenical species were observed in these waters, suggesting that there is a possible threshold level of total As concentration required, above which methylation of As by soil microorganisms takes place. In the acidic soils contaminated by mine tailings, arsenite was the major species present (up to 45% of total As in the aerobic soils and 79% of total As in the anaerobic soils). Although the soils were underlain by the unmineralized bedrock, soil As concentration ranged from 40.5 to 1290 ppm and As concentration in extracted porewaters from anaerobic soils ranged from 70.2 to 110 μg l −1 and in aerobic soil from 70.8 to 599 μg l −1. In the aerobic soils MMAA, DMAA, and arsenate were also present but only arsenate was found, along with arsenite, in the anaerobic soil porewaters.

Environmental effects of the usage of avermectins in livestock

Abamectin (avermectin B 1) and ivermectin (22,23-dihydroavermectin B 1) are high molecular weight hydrophobic compounds, active against a variety of animal parasites and insects. Numerous environmental fate and effects studies have been carried out in the development of these two compounds as antiparasitic agents and for abamectin as a crop protection chemical. They were found to be immobile in soil ( K oc≥4000), rapidly photodegraded in water (degradation half-life ( t 1 2 ) in the summer 0.5 days or less) and as thin films on surfaces ( t 1 2 <1 day ), and aerobically degraded in soil (ivermectin in soil/feces mixtures ( t 1 2 ) = 7–14 days ; avermectin B 1a in soils, ( t 1 2 =2–8 weeks ) to less bioactive compounds. Abamectin is not taken up from the soil by plans, nor is it bioconcentrated by fish (calculated steady-state bioconcentration factor of 52, with rapid depuration). Daphnia magna is the fresh water species found to be most sensitive to ivermectin and abamectin (LC 50 values of 0.025 and 0.34 ppb respectively); fish (e.g. rainbow trout) are much less sensitive to these compounds (LC 50 values of 3.0 ppb and 3.2 ppb, respectively). In the presence of sediment, toxicity toward Daphnia is significantly reduced. The metabolism and degradation of ivermectin and abamectin result in reduced toxicity to Daphnia. Abamectin and ivemectin possess no significant antibacterial and antifungal activity. They display little toxicity to earthworms (LC 50 values of 315 ppm and 28 ppm in soil for ivermectin and abamectin, respectively) or avians (abamectin dietary LC 50 values for bobwhite quail and mallard duck of 3102 ppm and 383 ppm, respectively), and no phytotoxicity. Residues of the avermectins in feces of livestock affect some dung-associated insects, especially their larval forms. This does not delay degradation of naturally formed cattle pats under field conditions; however, in some cases, delays have been observed with artificially formed pats. Based on usage patterns, the availability of residue-free dung and insect mobility, overall effects on dung-associated insects will be limited. As abamectin and ivermectin undergo rapid degradation in light and soil, and bind tightly to soil and sediment, they will not accumulate and will not undergo translocation in the environment, minimizing any environmental impact on non-target organisms resulting from their use.

Effects of RH 5849, a Novel Insect Growth Regulator, on Japanese Beetle (Coleoptera: Scarabaeidae) and Fall Armyworm (Lepidoptera: Noctuidae) in Turfgrass

RH 5849 (1,2-dibenzoyl-1-tert-butylhydrazine), a nonsteroidal ecdysone agonist representative of a novel class of insect growth regulators, was tested against larval and adult Japanese beetles, Popillia japonica Newman; and fall armyworm, Spodoptera frugiperda J.E. Smith, caterpillars in turf. RH 5849 was effective against Japanese beetle grubs at concentrations as low as 1 ppm in soil. Symptoms of toxicity included discoloration, weight loss, apparent neurotoxic effects, cessation of feeding, and developmentally premature, lethal molting at higher rates. Sublethal effects on overwintered third instars included earlier formation of prepupae. Against second-instar grubs, RH 5849 was nearly as effective as isazophos (Triumph 4E) at comparable rates in the field. Subsequent egg production by female beetles that fed once on RH 5849-treated sassafras foliage was reduced by 66-74%, but hatching success of eggs was not affected. RH 5849 caused premature molting and 100% mortality of fall amlyworms fed tall fescue foliage that wassprayed once with 30 or 100 ppm, or treated systemically through the roots. Systemic activity of RH 5849 is noteworthy because it could provide simultaneous control of both root-feeding and foliar-feeding turfgrass pests.

EFFECT OF SELENIUM FERTILIZATION ON THE CONCENTRATION OF SELENIUM, OTHER MINERALS, AND ASCORBIC ACID IN POTATOES

ABSTRACTThe effect of selenium fertilization on the concentration of selenium, other minerals, and ascorbic acid of Katahdin potato tubers was studied during each of two years. Sodium selenite was banded to the soil at rates of 5.6 (2.5), 11.2 (5.0) and 16.2 (7.5) kg/ha (ppm of soil). The tuber selenium concentration was increased significantly (p&lt;0.01) from 0.47 ppm to 0.93 ppm fresh weight. However, selenium levels in the soil greater than 5.0 ppm did not result in further increases in the selenium concentration of tubers. No significant effects due to selenium fertilization were observed for the concentration of other minerals and ascorbic acid. Similar trends were observed during both years of the study. In areas where the soil is low in selenium, addition of this element could prove useful in increasing the selenium content of potatoes, a very important vegetable in the American diet.

Improved Gas Chromatographic method for analysis of trichlorfon insecticide in soil and turfgrass thatch

Abstract An improved Gas Chromatographic method utilizing simple extraction and one‐step purification on solid phase extraction tubes was developed for analysis of trichlorfon as an intact insecticide compound in turfgrass thatch and soil. A Gas Chromatograph/Mass Spectrum (GC/MS) was used for confirmation of trichlorfon structure. The method readily determines trichlorfon in the presence of dichlorvos. Using an electron capture (EC) detector, the detection limits were 0.02 ppm in soil, 0.04 ppm in turfgrass thatch, and 0.09 ppm in soil, and 0.2 ppm in turfgrass thatch using an nitrogen phosphorus (NP) detector.

Determination of Phenolic Herbicides in Soil by Peroxyoxalate Chemiluminescence

Abstract Peroxyoxalate chemiluminescence was used for the determination of bromoxynil (3,5-dibromo-4-hydroxybenzonitrile), and bromofenoxim (3,5-dibromo-4-hydroxybenzaldehyde-0-(2,4-dinitrophenyloxime). Both compounds are potent herbicides and the presence of phenolic hydroxy group makes them amenable to analysis by peroxyoxalate chemiluminescence. Determinations were carried out in the soil, without prior separation. In contrast to previous analytical work, homogeneous solutions were used. Calibration curves are linear over a concentration range spanning three orders of magnitude and the limit of detection is 10 ppm in soil. para-Cyanophenol was also determined by peroxyoxalate chemiluminescence, and a limit of detection of 1 × 10−12M was found.

Activity of Cyromazine on Onion Maggot Larvae (Diptera: Anthomyiidae) in the Soil

A laboratory bioassay technique with soil was developed to investigate the toxicity and activity of the insect growth regulator, cyromazine, to onion maggot larvae, Delia antique (Meigen) (Diptera: Anthomyiidae). LC50’s (ppm in soil) for chlorpyrifos, fonofos, and cyromazine were 8.4, 9.4, and 17.5, respectively. Significant mortality due to cyromazine treatment was observed at the time of molt between first and second instar (72 h). Surviving larvae in soil treated with cyromazine developed more slowly than larvae in untreated soil. At 144 h, > 90% mortality occurred in the cyromazine treated soil compared with <10% in untreated soil. Because it has a different mode of action than the currently registered insecticides, cyromazine may have potential as a management tool for resistant populations, or in a resistance management program. Cyromazine may also be effective in controlling other soil insects.

Liquid Chromatographic Determination of Acifluorfen in Soil and Water

An analytical method based on the use of a liquid chromatograph equipped with a UV detector was developed for the determination of acifluorfen in soil and water. Acifluorfen was extracted from soil in methanol-0.10N NaOH (80 + 20 v/v) and from water by partition with dichloromethane. Solvent partitioning and solid-phase extraction were used to separate acifluorfen from major interfering sample components. Average recoveries from soil at 1, 0.1, and 0.01 ppm fortification levels were 95.1 +/- 3.4, 92.6 +/- 2.9, and 73.9 +/- 3.0%, respectively. Recoveries from water spiked at levels from 0.01 to 1 ppm averaged 96.5 +/- 5.4%. Method limits of detection were 0.006 ppm in soil and 0.003 ppm in water.

Gas-liquid chromatographic analysis of oxadiazon residues in turfgrass thatch and soil using a solid-phase extraction technique

Abstract A simple and inexpensive technique for analysis of oxadiazon (5‐tert‐butyl‐3‐(2,4‐dichloro‐5‐isopropoxyphenyl)‐1,3,4,‐oxadiazol‐2(3H)‐=one) residues in thatch and soil involving solid‐phase extraction/purification and final gas‐liquid chromatographic determination with nitrogen‐phosphorus specific detection has been developed. The method, sensitive to 0.08ppm for thatch and 0.04ppm for soil, significantly reduces the use of organic solvents and labor, and allows simultaneous analysis of multiple samples.

The critical levels and the maximum metal uptake for wheat and rice plants when applying metal oxides to soil

Wheat is more sensitive to CdO and ZnO compared with rice plant. The yield of wheat decreased by 30% in the presence of 30 ppm Cd, but that of rice plants by only 8%. The critical levels of meal uptake by wheat and rice plants for applying metal oxides to soil (CdO, ZnO, PbO) were determined. The highest concentration obtained for wheat grain was 141 micrograms/g Cd at the Cd 10,000 ppm in soil. This value is higher than the value of 4.97 micrograms/g for unpolished rice and higher than any other we have seen in the reports for treatment with CdO. Also, concentration of more than 1.0 micrograms/g Cd in wheat was observed at 5 pm Cd, while similar concentrations for rice plants were observed at 30 ppm Cd in soil.

Trace elements in soil and biota in confined disposal facilities for dreged material

We studied the relation of trace element concentrations in soil to those in house mice ( Mus musculus), common reed ( Phragmites australis) and ladybugs ( Coccinella septempunctata at five disposal facilities for dredged material. The sites had a wide range of soil trace element concentrations, acid soils and a depauperate fauna. They were very poor wildlife habitat because they were dominated by the common reed. Bioassay earthworms exposed to surface soils from three of the five sites died, whereas those exposed to four of five soils collected a meter deep survived, presumably because the deeper, unoxidized soil, was not as acid. Concentrations of Ni and Cr in the biota from each of the sites did not seem to be related to the concentrations of the same elements in soil. Although Pb, Zn and Cu concentrations in biota were correlated with those in soil, the range of concentrations in the biota was quite small compared to that in soil. The concentrations of Pb detected in mice were about as high as the concentrations previously reported in control mice from other studies. Mice from the most contaminated site (530 ppm Pb in soil) contained only slighly more Pb (8 ppm dry wt) than did mice (2–6 ppm dry wt) from sites containing much less Pb (22–92 ppm in soil). Despite the acid soil conditions, very little Cd was incorporated into food chains. Rather, Cd was leaching from the surface soil. We concluded that even the relatively high concentrations of trace elements in the acid dredged material studied did not cause high concentrations of trace elements in the biota.

Heavy metal tolerance of rice plants (Oryza sativa L.) to some metal oxides at the critical levels.

The toxicity of metal oxides (CdO, ZnO, PbO) were compared with each other and the critical levels of metal uptake by rice plants were determined. The order of metal toxicity to rice plants is CdO greater than ZnO greater than PbO. The highest concentration obtained for unpolished rice was 4.97 micrograms/g at the Cd 10,000 ppm in soil. This values is higher than every other we have seen in the reports for treatment with CdO. We are able to find out that the concentration of 10,000 ppm Cd in the form of CdO in the critical one towards rice plant. By contrast, such damage was not observed at even higher levels of ZnO and PbO were considered to have low toxicity toward rice plant. Also, a negative correlation between Zn or Cu accumulation in rice plants and Cd concentration in soil was found.

Alleviation of aluminum toxicity by phosphogypsum

Abstract Since the movement of lime down the soil profile is extremely limited and the incorporation of lime into subsoil requires large amounts of energy, the use of a soluble, surface applied ameliorant that would move into the deeper soil horizons resulting in amelioration of the subsoil is highly desirable. Phosphogypsum (PG), a by‐product of the phosphoric acid industry, has been evaluated for this purpose, and yield responses have been highly promising, although the mechanism of PG induced amelioration of subsoil acidity is not clear. Effects of PG on subsoil solution properties and aluminum (Al) speciation have been evaluated in this study. A subsoil sample from the Appling series’ (Typic Hapludults) was treated with either increasing levels of PG (2, 5, and 10 Mg ha‐1 PG), reagent‐grade CaSO4.2H2O (2 Mg ha‐1), or CaCl2.2H2O (2 Mg ha‐1) and incubated (22 ± 2°C) at ‐0.01 MPa moisture potential. Soil solution was extracted after 14 and 40 d by centrifugation at 2500 g. Soil solution pH was 5.67 in untreated soil, while increasing application of PG from 2 to 10 Mg ha‐1 decreased the soil solution pH from 5.08 to 4.47. The soil solution pH was higher in soils treated with similar rates of PG or CaSO4.2H2O than CaCl2.2H2O. Increasing levels of PG increased the concentrations of Ca, Mg, K, P, Na, Si, Mn, F and SO4 in the soil solution. The concentration of total Al in soil solution was 0.02, 1.95 and 5.25 ppm in soils treated with 2, 5 and 10 Mg ha‐1 PG, respectively. However, Al speciation predicted by the GEOCHEM computer program revealed that at the 5 Mg ha‐1 PG treatment, 99% and 0.6% of total Al was complexed with F and SO4, respectively, while only 0.3% was in Al3+ form. At the 10T ha‐1 PG treatment, although 10% of total Al was in Al3+ form, the activity of Al was only 0.11 ppm. Therefore, an increase in concentrations of F and SO4 in soil solution in PG treated soils may alleviate Al toxicity by formation of less phytotoxic Al‐F and A1‐SO4 complexes. The toxicity of Al may be further decreased by a reduction in activity of Al3+ due to an increase in soil solution ionic strength in PG treated soils.

Thin -layer Chromatographic Separation and Identification of Carbofuran and Two Carbamate Metabolites and their Dinitrophenyl Ethers

Abstract Residues of carbofuran and its 2 carbamate metabolites in fortified fresh water, a sandy loam soil, and plant tissues were extracted with HCl, partitioned into methylene chloride and cleaned up on deactivated Florisil. Aliquots of extracts were chromato-graphed on silica gel G and GF plates and carbofuran, 3-hydroxycarbofuran, and 3-ketocarbofuran were hydrolysed into their 7-phenols with KOH spray. Spots were visualized with either p-nitrobenzenediazonium fluoroborate or 2,6-dibromobenzo-quinone-4-chloroimine. The characteristic color of spots before and after spraying with KOH or with either of the chromogenic reagents in ordinary light and under UV light helped in identification and differentiation of the compounds. As low as 0.05ppm in water and 0.2ppm in soil or strawberry, lettuce, carrots, peas and potatoes could be detected. 3-Hydroxycarbofuran in the remaining extracts was converted into 3-ethoxycarbofuran and the compounds were converted into their dinitrophenols and chromatographed on silica gel GF. Good separation of compounds was obtained but the limit of detection was 0.1 ppm in water and 0.3 ppm in soil and plant tissues. The procedures were applicable to field-treated rutabaga samples and useful in identity confirmation.

Extraction and Cleanup of Soil Arsenical Residues for Analysis by High Pressure Liquid Chromatographic–Graphite Furnace Atomic Absorption

Abstract An analytical procedure for the extraction and cleanup of arsenical residues from soil was developed to meet the specific requirements for separation by high pressure liquid chromatography (HPLC) and on-line analysis by a graphite furnace atomic absorption spectrophotometer (GFAA). Soil samples were extracted with 2M aqueous NH4OH, cleaned on a carbon-Celite chromatographic column, concentrated to 1 g soil extract equivalent per mL, and determined by HPLC-GFAA. Recovery values were as follows: dimethylarsinic acid (cacodylic acid, CA) 90%; methanearsonic acid (MAA) 83%; arsenate 56%; and arsenite 64%. The limit of detection was 0.5 ppm in soil. Additional cleanup on cellulose thin layer chromatographic (TLC) plates improved sensitivity to less than 0.1 ppm and also served for confirmation of identity. The soil extract matrix did not appear to affect GFAA signal response. High salt content in concentrated soil samples altered the dimethylarsinic acid HPLC retention volume. By the time of analysis, arsenite was completely oxidized to arsenate in soil extractant.

Excess trace metal effects on calcium distribution in plants

Abstract One of the most important roles of Ca in plants is that of protecting against toxicities of trace metals. Even though this is a function of Ca, at least some of the trace metals in excess do inhibit uptake and/or translocation of Ca. Managanese, when supplid at a very high level to bush beans (Phaseolus vulgaris L. cultivar Improved Tender‐green) in solution culture, decreased Ca concentration in leaves, stems, and roots. The inhibition was pronounced for 10(E‐3) and 10(E‐2) M Mn. The decrease for the latter was 76% for leaves, 61% for stems, and 49% for roots. Molybdenum at 10(E‐3) M decreased bush bean leaf, stem, and root concentrations of Ca by 38%, 24%, and 16%, respectively. Vanadate at 10(E‐5) M decreased bush bean concentrations of Ca in leaves, stems, and roots by 37%, 50%, and 11%, respectively. Silver at 10(E‐5) M decreased Ca in leaves by 67%. Cadmium at 10(E‐4) M decreased leaf, stem, and root Ca by 76%, 28%, and 61%, respectively. Lithium at 50 ppm in soil decreased yields of bush b...

Gas-Liquid Chromatographic Determination of the Plant Growth Regulator Ancymidol in Plant Tissue, Soil, and Water

Abstract A method is presented for the determination of the plant growth regulator ancymidol (α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol) in plant tissue, soil, and water. Residues are converted to an electron-capturing derivative with phosphorus tribromide prior to analysis by gas-liquid chromatography. The method is sensitive to about 0.10 ppm for plant tissue, 0.02—0.05 ppm for soil, and 0.02 ppm for water. Recoveries have averaged greater than 70% for all types of samples.

Effect of aldrin on nodulation, nitrogen fixation and yield of bengal gram (Cicer arietinum)

The effect of aldrin on nodulation (nodule number and their dry weight) in bengal gram (Cicer arietinum) was not very clear. Aldrin decreased nitrogen fixation and yield at the concentration of 1, 5 and 10 ppm in soil. The application of farm yard manure eliminated completely the adverse effects on yield and partially, the adverse effects on nitrogen fixation. There was an increase in yield with the application of aldrin along with farm yard manure. Nodulation and nitrogen fixation at 1 ppm level of aldrin were more than control in presence of FYM. re]19760102

Mirex in the environment: its degradation to kepone and related compounds.

The chlorocarbon mirex undergoes slow, successive loss of chlorine in the field to a series of related compounds that had lost one or more chlorine atoms. Soil samples were recovered 12 years after treatment at 1 part per million (ppm), and ant bait was recovered 5 years after an aircraft crash. As much as 50 percent of the original mirex was recovered at levels of about 0.5 and 640 ppm, respectively. Kepone was present at levels of 0.02 ppm in soil and 10 ppm in the bait or up to 10 percent of the recovered mirex, as determined by combined techniques of chromatography and mass spectrometry. This constitutes the first observation of the degradation of mirex in nature, and demonstrates a pathway for its eventual disappearance from the environment.

Environmental Contamination of Flue-Cured Tobacco with Chlorinated Hydrocarbon Insecticides

AbstractIndirect contamination of tobacco by DDT, TDE, endrin, dieldrin, and toxaphene was investigated under field conditions. Levels of DDT + TDE in soil ranged from &lt;&lt; 0.01 to 0.18 ppm, and those in cured leaves ranged from 0.11 to 1.69 ppm. The lower stalk position at the major test location generally had greater concentrations of DDT + TDE than the middle and upper positions, but distribution of these insecticides among leaf positions was variable for other locations. Residues of DDT in the bottom stalk position were positively correlated with those in the soil. Plant-bed soils did not appear to be a major source of DDT + TDE residues in cured tobacco. Residues of endrin and dieldrin were near or below the limit of detection (0.01 ppm) in soil and cured leaf. Residues of toxaphene ranged from &lt;&lt; 0.1 to 4.7 ppm in soil and &lt;&lt; 0.3 to 7.7 ppm on tobacco. Toxaphene residues in the bottom and top stalk positions were positively correlated with residues in soil. Contamination by toxaphene appeared to be attributable to uptake from soil and to movement of the insecticide as drift or vapour through the air.