The combination of oxalic acid with power ultrasound fully degrades chrysotile asbestos fibres

The simultaneous action of power ultrasound and oxalic acid, as a chelating agent, rapidly converts chrysotile asbestos into water soluble material and a non-asbestos debris, not classifiable as hazardous under worldwide safety regulations.     

Survey on fluoride, bromide and chloride contents in public drinking water supplies in Sicily (Italy)

Six hundred and sixty-seven water samples were collected from public drinking water supplies in Sicily and analysed for electric conductivity and for their Cl(-), Br(-) and F(-) contents. The samples were, as far as possible, collected evenly over the entire territory with an average sampling density of about one sample for every 7,600 inhabitants. The contents of Cl(-) and Br(-), ranging between 5.53 and 1,302 mg/l and between <0.025 and 4.76 mg/l respectively, correlated well with the electric conductivity, a parameter used as a proxy for water salinity. The highest values were found both along the NW and SE coasts, which we attributed to seawater contamination, and in the central part of Sicily, which we attributed to evaporitic rock dissolution. The fluoride concentrations ranged from 0.023 to 3.28 mg/l, while the highest values (only three exceeding the maximum admissible concentration of 1.5 mg/l) generally correlated either with the presence in the area of crystalline (volcanic or metamorphic) or evaporitic rocks or with contamination from hydrothermal activity. Apart from these limited cases of exceeding F(-) levels, the waters of public drinking water supplies in Sicily can be considered safe for human consumption for the analysed parameters. Some limited concern could arise from the intake of bromide-rich waters (about 3% exceeding 1 mg/l) because of the potential formation of dangerous disinfection by-products.     

Possible use of Serratia marcescens in toxic metal biosorption (removal)

Background, aim and scope  

Metal pollution is a serious problem for environmental safety and programmes of monitoring and bioremediation are needed. Among the processes of bioremediation, the use of microbes to remove and degrade contaminants is considered a biotechnological approach to clean up polluted environments.     

Effect of buffer strips and soil texture on runoff losses of flufenacet and isoxaflutole from maize fields

The influence of buffer strips and soil texture on runoff of flufenacet and isoxaflutole was studied for two years in Northern Italy. The efficacy of buffer strips was evaluated on six plots characterized by different soil textures; two plots had Riva soil (18.6% sand, 63.1% silt, 18.3% clay) while the remaining four plots had Tetto Frati (TF) soil (37.1% sand, 57% silt, 5.9% clay). Additionally, the width of the buffer strips, constituted of spontaneous vegetation grown after crop sowing, was also compared for their ability to abate runoff waters. Chemical residues in water following runoff events were investigated, as well as their dissipation in the soil. After the first runoff events, concentrations of herbicides in water samples collected from Riva plots were as much as four times lower in waters from TF plots. On average of two growing seasons, the field half-life of flufenacet in the upper soil layer (5 cm) ranged between 8.1 and 12.8 days in Riva soil, 8.5 and 9.3 days in TF soil. Isoxaflutole field half-life was less than 1 day. The buffer strip was very affective by the uniformity of the vegetative cover, particularly, at the beginning of the season. In TF plots, concentration differences were generally due to the presence or absence of the buffer strip, regardless of its width.     

The influence of environmental factors on the molluscicidal activity of Euphorbia milii latex

Abstract

The present study was undertaken to investigate the influence of biotic (snail size and presence of food during the test) and abiotic factors (temperature, water hardness and concentration of organic materials) on the molluscicidal activity of Euphorbia milii latex. Bioassays were conducted with B. glabrata (10 snails per concentration) and snail lethality was evaluated after 24 hr and 48 hr of exposure to lyophilized latex solutions. Neither the degree of water hardness, nor the presence of food during the test affected latex‐induced snail mortality. The snail size had a minor influence on E.milii‐induced snail lethality. Newly‐hatched (shell diameter ≤ 1mm) as well as young (3–8 mm) snails were slightly less susceptible than older (10–25 mm) mollusks. On the other hand, the molluscicidal effect of E.milii latex was modified by environmental factors such as temperature (i.e. LC₅₀ and LC₉₀ values were halved for every 10°C rise in temperature) and concentration of organic materials in the water (i.e. the higher the concentration of organic matter, the higher the LC₅₀ value). The efficacy of E.milii latex as a molluscicide can be modified by factors such as water temperature and concentration of organic materials, and to a lesser extent by snail size.     

Runoff and leaching of atrazine and alachlor on a sandy soil as affected by application in sprinkler irrigation

Abstract

Rainfall simulation was used with small packed boxes of soil to compare runoff of herbicides applied by conventional spray and injection into sprinkler‐irrigation (chemigation), under severe rainfall conditions. It was hypothesized that the larger water volumes used in chemigation would leach some of the chemicals out of the soil surface rainfall interaction zone, and thus reduce the amounts of herbicides available for runoff. A 47‐mm rain falling in a 2‐hour event 24 hours after application of alachlor (2‐chloro‐N‐(2,6‐diethylphenyl)‐N‐(methoxymethyl)‐acetamide) and atrazine (6‐chloro‐N‐ethyl‐N‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine) was simulated. The design of the boxes allowed a measurement of pesticide concentrations in splash water throughout the rainfall event. Initial atrazine concentrations exceeding its’ solubility were observed. When the herbicides were applied in 64000 L/ha of water (simulating chemigation in 6.4 mm irrigation water) to the surface of a Tifton loamy sand, subsequent herbicide losses in runoff water were decreased by 90% for atrazine and 91% for alachlor, as compared to losses from applications in typical carrier water volumes of 187 L/ha. However, this difference was not due to an herbicide leaching effect but to a 96% decrease in the amount of runoff from the chemigated plots. Only 0.3 mm of runoff occurred from the chemigated boxes while 7.4 mm runoff occurred from the conventionally‐treated boxes, even though antecedent moisture was higher in the former. Two possible explanations for this unexpected result are (a) increased aggregate stability in the more moist condition, leading to less surface sealing during subsequent rainfall, or (b) a hydrophobic effect in the drier boxes. In the majority of these pans herbicide loss was much less in runoff than in leachate water. Thus, in this soil, application of these herbicides by chemigation would decrease their potential for pollution only in situations where runoff is a greater potential threat than leaching.     

The degradation of anilazine and dihydroxy‐anilazine at various soil depths of an orthic luvisol

Abstract

In conformity with Guideline 4.1 of the Federal German Biological Agency, degradation experiments with the fungicide active ingredient [benzene ring‐U‐¹⁴C]anilazine and its major metabolite [triazine ring‐U‐¹⁴C]dihydroxy‐anilazine were carried out in an orthic luvisol. Mineralization of the benzene ring carbon of anilazine amounted to less than 2 % in 110 days and that of the triazine ring carbon of dihydroxy‐anilazine to less than 8 %. Increasing the incubation temperature from 22 °C to 30 °C and adding organic substance influenced the mineralization slightly. In soils which received two or three applications in succeeding years with subsequent ageing in the open‐air lysimeter no stimulation of the mineralization was observed. Extractions after incubation showed that only 10.2 to 18.6 % of the ¹⁴C‐activity applied with anilazine was extractable with acetone/CaCl₂. The major proportion was bound in the fractions of the soil organic matter, namely 45.0 to 59.6 % of the radiocarbon applied was accounted for by the humin fraction, 12.0 to 27.4 % by the fulvic acids, and 9.4 to 15.0 % by the humic acids. In the case of dihydroxy‐anilazine, 28.9 to 89.7 % of the applied ¹⁴C‐activity was extractable with acetone/CaCl₂. Of tJhe radiocarbon bound in the soil, the greatest proportion, i.e. 18.5 to 35.5 % of the radiocarbon applied, was accounted for by the fulvic acids.     

Chemical and biological release of 14C‐bound residues from soil treated with 14C‐p,p'‐DDT

Abstract

¹⁴C‐p,p'‐DDT‐bound residues in soil can be released by treatment with concentrated sulphuric acid at ambient temperatures. Within 6 days, about 70% of the bound residues was released. Bound residues released after 9 months incubation with ¹⁴C‐DDT showed the presence of DDT and DDE only while bound residues released after 18 months, contained in addition 13% DDD.

Release of bound ¹⁴C‐residues also occurs readily following inoculation of the soil‐bound residues with fresh soil or with individual microorganisms. Almost complete release of bound residues was observed after incubation for 45 days. The rate of release was rapid during the first two weeks and decreased thereafter. TLC and HPLC analysis showed that the released residues contained DDE (about 80%) and a smaller amount of DDD. The disappearance of DDT from the released residues may be attributed to its microbiological degradation to DDE and DDD, shortly after its release.     

Carbofuran degradation in soil profiles

Abstract

Two soils, Puyallup fine sandy loam from Puyallup, WA, and Ellzey fine sand from Hastings, FL, each with a prior history of carbofiiran exposure but with different pedological and climatological characteristics, were found to exhibit enhanced degradation toward carbofiiran in surface and subsurface soil layers. The treated Puyallup and Ellzey soils exhibited higher mineralization rates for both the carbonyl and the aromatic ring of carbofiiran when compared to untreated soils. Disappearance rates of [¹⁴C‐URL (uniformly ring labeled)] carbofiiran in the treated Ellzey soil was faster than in untreated soil, and also faster in surface soil than in subsurface soil. Initial degradation patterns in the treated Ellzey soil were also different from those in the untreated soil. The treated Ellzey soil degraded carbofuran mainly through biological hydrolysis, while untreated soil degraded carbofuran through both oxidative and hydrolytic processes.