Effect of salinity on the fate of pesticides in irrigated systems: a first overview.

This review investigates the impact of salinity on the fate of the active compounds of pesticides in a cultivated environment. Due to the over-exploitation of water resources and intensification of agriculture, salinity outbreaks are being observed more often in cultivated fields under pesticide treatments. Nevertheless, there is a poor understanding of the incidence of varying water salt loads on the behavior of pesticides' active ingredients in soil and water bodies. The present review established that water salinity can affect the diffusion of pesticides' active ingredients through numerous processes. Firstly, by increasing the vapor pressure and decreasing the solubility of the compounds, which is known as the salting-out effect, salinity can change the colligative properties of water towards molecules and the modification of exchange capacity and sorption onto the chemicals. It has also been established that the osmotic stress induced by salinity could inhibit the biodegradation process by reducing the activity of sensitive microorganisms. Moreover, soil properties like dissolved organic matter, organic carbon, clay content, and soil texture control the fate and availability of chemicals in different processes of persistence in water and soil matrix. In the same line, salinity promotes the formation of different complexes, such as between humic acid and the studied active compounds. Furthermore, salinity can modify the water flux due to soil clogging because of the coagulation and dispersion of clay particle cycles, especially when the change in salinity ranges is severe.

Evidence for enhanced dissipation of chlorpyrifos in an agricultural soil inoculated with Serratia rubidaea strain ABS 10.

The insecticide 14C-chlorpyrifos was found mineralized in a Tunisian soil with repeated exposure to it. From this soil, a bacterial strain was isolated that was able to grow in a minimal salt medium (MSM) supplemented with 25 mg L-1 of chlorpyrifos. It was characterized as Serratia rubidaea strain ABS 10 using morphological and biochemical analyses, as well as 16S rRNA sequencing. In a liquid culture, the S. rubidaea strain ABS 10 was able to dissipate chlorpyrifos almost entirely within 48 h of incubation. Although the S. rubidaea strain ABS 10 was able to grow in an MSM supplemented with chlorpyrifos and dissipate it in a liquid culture, it was not able to mineralize 14C-chlorpyrifos. Therefore, it can be concluded that the dissipation capability of this bacteria might be attributed to its capacity to adsorb CHL. It can also be ascribed to other reasons such as the formation of biogenic non-extractable residues. In both non-sterile and sterile soil inoculated with S. rubidaea strain ABS 10, chlorpyrifos was more rapidly dissipated than in controls with DT50 of 1.38 and 1.05 days, respectively.

Perurethral transvesical route for oocytes retrieval: an old technique for a new indication in oncofertility.

We aimed to evaluate the safety and efficiency of the peruretheral transvesical oocyte retrieval in oncofertility. We conducted a retrospective comparative study in our assisted reproductive technologies center. STUDY GROUP: 28 pubertal young women affected by malignancies, referred for fertility preservation and refusing transvaginal (TV) procedure. CONTROL GROUP: 28 infertile patients, aged less than 25 years, who have undergone in vitro fertilization with TV oocyte retrieval. The ovarian stimulation was significantly longer on the study group. There was no difference between the two groups regarding mean number of collected metaphase II oocytes. One patient of the study group had a transient dysuria. These preliminary data suggest that, in oncofertility, peruretheral transvesical oocyte retrieval is an alternative when the TV route is refused or not feasible.

Progesterone for Luteal Phase Support in In Vitro Fertilization: Comparison of Vaginal and Rectal Pessaries to Vaginal Capsules: A Randomized Controlled Study.

BACKGROUND: In IVF, Luteal phase support is usually performed using vaginal progesterone. A part of patients using this route reports being uncomfortable with this route. We tried to study whether the rectal route could be an effective alternative and associated with less discomfort. PATIENTS AND METHODS: A prospective randomized controlled study. All patient were eligible for IVF treatment for infertility. After oocyte pickup, 186 patients were allocated to one the following protocols for luteal phase support: (i) rectal pessaries group: natural progesterone pessaries administered rectally 200 mg three times a day, (ii) vaginal pessaries group: natural progesterone pessaries administered vaginally 200 mg three times a day), and (iii) vaginal capsules group: natural micronized progesterone capsules administered vaginally 200 mg three times a day. On the day of pregnancy test, patients were asked to fill in a questionnaire conducted by an investigator in order to assess the tolerability and side effects of the LPS treatment taken. The primary endpoint was the occurrence of perineal irritation. RESULTS: Fifty eight patients were assigned to the rectal pessaries group, 68 patients to the vaginal pessaries group, and 60 patients to the vaginal capsules group. All patients adhered to their allocated treatment. Implantation and clinical pregnancy rates per transfer did not differ between the three groups. Perineal irritation, which was our primary endpoint, was the same for all the three groups (respectively 1.7 % versus 5.9 % versus 11.7%). Regarding the other side effects, more patients experienced constipation and flatulence with the rectal route, whereas more patients reported vaginal discharge in the vaginal capsules group. CONCLUSION: Rectal administration for luteal phase support is effective and well accepted alternative to vaginal route.

Isolation and characterisation of a bacterial strain degrading the herbicide sulcotrione from an agricultural soil.

BACKGROUND: The dissipation kinetics of the herbicide sulcotrione sprayed 4 times on a French soil was studied using a laboratory microcosm approach. An advanced cultivation-based method was then used to isolate the bacteria responsible for biotransformation of sulcotrione. Chromatographic methods were employed as complementary tools to define its metabolic pathway. RESULTS: Soil microflora was able quickly to biotransform the herbicide (DT(50) ≈ 8 days). 2-Chloro-4-mesylbenzoic acid, one of its main metabolites, was clearly detected. However, no accelerated biodegradation process was observed. Eight pure sulcotrione-resistant strains were isolated, but only one (1OP) was capable of degrading this herbicide with a relatively high efficiency and to use it as a sole source of carbon and energy. In parallel, another sulcotrione-resistant strain (1TRANS) was shown to be incapable of degrading the herbicide. Amplified ribosomal restriction analysis (ARDRA) and repetitive extragenic palendromic PCR genomic (REP-PCR) fingerprinting of strains 1OP and 1TRANS gave indistinguishable profiles. CONCLUSION: Sequencing and aligning analysis of 16S rDNA genes of each pure strain revealed identical sequences and a close phylogenetic relationship (99% sequence identity) to Pseudomonas putida. Such physiological and genetic properties of 1OP to metabolise sulcotrione were probably governed by mobile genetic elements in the genome of the bacteria.

Behaviour of sulcotrione and mesotrione in two soils.

The behaviour of sulcotrione, a recently introduced triketone herbicide, in various soil types was studied under laboratory conditions. In particular, degradation and sorption processes were examined on Ghent and Perpignan soils. Kinetics showed that the degradation of sulcotrione was influenced by biotic and/or abiotic factors. Half-lives ranged between 45 and 65 days. Among the degradation compounds identified were 1,3-cyclohexanedione (CHD) and 2-chloro-4-mesyl benzoic acid (CMBA), previously described as hydrolysis products, and, under special conditions, a derivative of phenylheptanoic acid (PHD). This new degradation product suggested that sulcotrione could follow two possible pathways in the soil, as in water. During the sorption study, a moderate retention of sulcotrione and CMBA relative to CHD and PHD, which were highly adsorbed whatever the soil type, was reported. Experiments carried out under the same conditions for sulcotrione and mesotrione, another triketone herbicide recommended in maize culture, made it possible to compare the two triketones and to conclude that they exhibited relatively similar behaviour in the soil, i.e. that their leaching potential needs to be properly addressed and risks evaluated.

Photodegradation of sulcotrione in various aquatic environments and toxicity of its photoproducts for some marine micro-organisms.

Photochemical behaviour of sulcotrione, a triketone herbicide, was studied in a variety of aqueous solutions including natural waters (sea and river) under laboratory conditions. Photodegradation experiments were carried out under two irradiation systems (UV-B and simulated solar radiation) in order to evaluate kinetics of active ingredient. The degradation kinetics, more rapid under UV-B radiation than solar simulator, followed a first-order reaction (photolysis half-lives ranged between 3 and 50 h) and appeared strongly dependent on water origin, pH value and molecular structure of the herbicide. Dissolved organic matter showed a retarding effect while low concentrations of nitrate ions had no effect on photolysis rate. Identification of photoproducts indicated that hydrolysis, a pH-dependent process (no degradation at pH >6 but at pH=3, k=0.0344 h(-1)), could be photoassisted. These results were compared to those of mesotrione, another triketone herbicide, which appeared more stable under UV-B irradiation. Toxicological studies on two marine heterotrophic bacteria and one cyanobacterium showed absence of effects up to 100 microgL(-1) for both sulcotrione and its photoproducts.

Influence of soil properties on the adsorption-desorption of sulcotrione and its hydrolysis metabolites on various soils.

The retention process of sulcotrione and its two hydrolysis products, 1,3-cyclohexanedione (CHD) and 2-chloro-4-methylsulfonylbenzoic acid (CMBA), were studied in four different soils (Belgium, Landes, Perpignan, and Martinique) under laboratory conditions. Adsorption isotherms were well fitted by a Freundlich relationship. The values of K(fa) ranged from 0.4 to 27.0, and the most adsorbed compound was CHD regardless the soil type. Sulcotrione and CMBA exhibited similar retention behaviors. According to adsorption and desorption results, sulcotrione presents a moderate affinity with soil components; however, its leaching capacity needs to be carefully assessed. Clay content seemed to be the most important factor influencing the adsorption capacity of each compound, whereas organic matter and pH had little influence. The soils were classified according to their adsorption capacity in the following decreasing order: Martinique, Belgium, Landes, Perpignan.