Higher-tier assessment of the potential for groundwater issues due to the use of 1,3-D soil fumigant; evaluation of the active ingredient, metabolites and potentially related chlorinated compounds

BACKGROUND: 1,3‐Dichloropropene (1,3‐D, CAS No. 542‐75‐6) is a broad‐spectrum soil fumigant used to control numerous species of soilborne plant‐parasitic nematodes. 1,3‐D consists of two isomers, (Z)‐ and (E)‐1,3‐D. There are a number of low‐level chlorinated compounds that could potentially be produced as a part of the 1,3‐D manufacturing process. 1,3‐D and its metabolites, as well as potentially related chlorinated compounds, represent potential groundwater contaminants. RESULTS: This study has investigated the hydrolytic stability, under biotic and abiotic conditions in the laboratory, of an extensive representative list of 1,3‐D and potentially related chlorinated compounds in order to predict their environmental fate. All of these compounds showed intrinsic hydrolytic instability under both abiotic and biotic test conditions. Furthermore, a monitoring programme was carried out. Twenty‐five wells were monitored in five Italian regions characterised by historical and existing use of 1,3‐D. The parent compound, its two major metabolites and potentially related chlorinated compounds were not detected in the well water at > 0.1 µg L^?1 at any sampling location. CONCLUSION: The soil fumigant (E,Z)‐1,3‐D, its metabolites and potentially related chlorinated compounds constitute a low risk to groundwater. Copyright © 2011 Society of Chemical Industry     

Sunflower seed meal as a protein source in diets for Tilapia rendalli (Boulanger, 1896) fingerlings

This study tested the use of sunflower seed meal as a dietary protein replacement for fishmeal in practical diets for tilapia fingerlings. In order to determine the optimum substitution level for this species, sunflower seed meal was used to replace 10%, 20%, 30%, 40% and 50% of the fishmeal protein in diets containing 40% protein overall. During a 70‐day feeding period, diets containing 10% and 20% plant protein provided the best growth and feeding efficiency results, with values statistically similar to those of the control diet based on fishmeal as the sole protein. The unitary feeding cost index showed the highest profit with diets containing 20% sunflower seed meal. Growth depletion observed with diets containing higher sunflower seed meal percentages is explained by increasing Phe and Met deficiencies, and high non‐digestible fibre content. It was concluded that sunflower seed meal is a suitable feed ingredient for tilapia complete diets when it constitutes up to 20% of the dietary protein.     

In vitro generation of mature neutrophils from canine Lin- bone marrow cells

The major goal of this work was to describe the in vitro generation of mature functional neutrophils derived from a canine enriched haematopoietic progenitor cell population. We have utilised lineage depletion by immunomagnetic selection to isolate a canine haematopoietic progenitor cell population. The physical, immunological, metabolical and morphological methodologies employed in this study have permitted us to isolate and define a cell population enriched in Rh-123low and CD34+ cells. Irradiated pre-established long-term bone marrow cultures (LTBMC) were utilised to determine the self-renewal ability of lineage negative (Lin-) cells, as well as their capacity to differentiate into mature functional neutrophils. The authors demonstrate for the first time that canine neutrophils derived from Lin- cells are able to produce oxyradicals, express a specific neutrophil surface antigen, and contain gelatinase granules. These characteristics enable them to migrate through basement membranes to act as a first line defence mechanism. The fact that these cells are able to differentiate into functional mature cells, and give rise to long-term culture-initiating cells (LTC-IC) after 35 days of culture, allows the authors to assure that the isolated canine enriched haematopoietic cell population exhibit functional characteristics, associated with primitive haematopoietic cells.     

Chlorophyll fluorescence as a marker for herbicide mechanisms of action

Photosynthesis is the single most important source of O₂ and organic chemical energy necessary to support all non-autotrophic life forms. Plants compartmentalize this elaborate biochemical process within chloroplasts in order to safely harness the power of solar energy and convert it into usable chemical units. Stresses (biotic or abiotic) that challenge the integrity of the plant cell are likely to affect photosynthesis and alter chlorophyll fluorescence. A simple three-step assay was developed to test selected herbicides representative of the known herbicide mechanisms of action and a number of natural phytotoxins to determine their effect on photosynthesis as measured by chlorophyll fluorescence. The most active compounds were those interacting directly with photosynthesis (inhibitors of photosystem I and II), those inhibiting carotenoid synthesis, and those with mechanisms of action generating reactive oxygen species and lipid peroxidation (uncouplers and inhibitors of protoporphyrinogen oxidase). Other active compounds targeted lipids (very-long-chain fatty acid synthase and removal of cuticular waxes). Therefore, induced chlorophyll fluorescence is a good biomarker to help identify certain herbicide modes of action and their dependence on light for bioactivity.     

Potential operator exposure to procymidone in greenhouses.

Recent legislation in the European Union requires regulators of member states to carry out risk assessments using data for actual or potential operator exposure, or estimates of exposure from models. However, the existing models have few datasets from studies carried out on greenhouse or indoor crops, particularly in southern Europe. In this study potential dermal and inhalatory exposures were measured in two trials in Italian greenhouses. The total potential dermal operator exposure of the applicator, measured with a whole-body passive dosimetry method, was 15.4 and 37.1 mL/h of the diluted pesticide mixture. The majority of the contamination was on the hands and on the lower part of the coverall. Approximately 0. 003% of the active ingredient (ai) applied to the crop area contaminated the coverall worn by the operator. The potential dermal exposure during the mixing and loading phase accounted for 6-8% of the total potential dermal exposure during the whole process. Inhalation exposure accounted for only 0.05-0.07% of the total potential operator exposure. Model predictions of the potential operator exposure using a modified version of the German model overestimate the mixing-loading exposure while underestimating the application exposure. These data are evidence that the estimation coefficient set for hand-held application to ornamental and horticultural crops may be inadequate for the agronomic conditions of southern Europe.     

Anaesthetic and antioxidant effects of Myrcia sylvatica (G. Mey.) DC. and Curcuma longa L. essential oils on tambaqui (Colossoma macropomum)

Anaesthetic substances are necessary to reduce fish stress during aquaculture activities. The objectives of this study were: (i) to determine the efficacy of essential oils (EOs) of Myrcia sylvatica (EOMS) and Curcuma longa (EOCL) as anaesthetics for Colossoma macropomum and (ii) to evaluate the effects of rapid anaesthesia and long‐term sedation (6 h) with these oils. Therefore, the main primary stress indicator (cortisol) and secondary factors (biochemical indices, hepatic metabolism, oxidative biomarkers) were measured. Sedation with the EOCL resulted in lower cortisol levels compared to control group. Total cholesterol levels were lower in fish sedated with EOMS than in control. Lactate levels were higher in fish anaesthetized with both EOs and sedated with EOCL compared to control. Both EOs increased hepatic glycogen levels after anaesthesia and EOMS increased this parameter after sedation compared to control. Anaesthesia and sedation with EOs resulted in lower levels of lipid peroxidation (LPO) compared to control. In turn, the activity of some antioxidant enzymes evaluated (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione‐S‐transferase), the content of non‐protein thiols and total reactive antioxidant potential were higher in tissues of fish anaesthetized and sedated with EOs compared to control. This induction of antioxidant capacity in the tissues could be due to the antioxidant property exerted by these EOs. Thus, EOMS and EOCL are recommended for anaesthesia and sedation of fish because in spite of inducing anaerobic metabolism, these EOs did not alter most biochemical parameters, reduced the LPO and increased the antioxidant capacity in vital tissues.     

Silver catfish Rhamdia quelen immersion anaesthesia with essential oil of Aloysia triphylla (L'Hérit) Britton or tricaine methanesulfonate: effect on stress response and antioxidant status

Responses to anaesthesia with essential oil (EO) of Aloysia triphylla (135 and 180 mg L^?1) and tricaine methanesulfonate (MS222) (150 and 300 mg L^?1) were assessed in silver catfish. Exposure to the anaesthetics elicited a stress response in the species. In the case of MS222, it was displayed as a release of cortisol into bloodstream, elevation in hematocrit and plasma ion loss. The EO presented cortisol‐blocking properties, but increased haematocrit and disturbances of hydromineral balance were observed. Liver antioxidant/oxidant status of EO and MS222‐anaesthetized silver catfish was also estimated. The synthetic anaesthetic induced lipoperoxidation, notwithstanding increased catalase contents, whereas the naturally occurring product was capable of preventing the formation of lipid peroxides, possibly due to combined actions of catalase and glutathione‐S‐transferase. Anaesthetic efficacy was also tested via induction and recovery times. Overall, the promising results obtained for the physiological parameters of the EO‐treated fish counterbalanced the slight prolonged induction time observed for 180 mg L^?1. As for 135 mg L^?1, both induction and recovery times were lengthy; despite that, the EO was able to promote oxidative protection and mitigate stress. None of the MS222 concentrations prompted such responses concomitantly.     

Induction of resistance to Sclerotium rolfsii in different varieties of onion by inoculation with Trichoderma asperellum

We evaluated the ability of Trichoderma asperellum Samuels, Lieckfeldt & Nirenberg to induce resistance to the fungal plant pathogen, Sclerotium rolfsii Saccardo, in three onion (Allium cepa L.) varieties. Both the severity of disease and the activities of glucanase, chitinase and peroxidase (enzymes involved in plant resistance) were evaluated in onions inoculated with T. asperellum alone, S. rolfsii alone, or both T. asperellum and S. rolfsii (dual-inoculation) and compared to uninoculated (control) plants. In dual inoculations, the presence of T. asperellum reduced the severity of disease symptoms caused by S. rolfsii. Inoculation with T. asperellum alone increased glucanase, chitinase and peroxidase activity in bulbs, roots and leaves of all three onion varieties compared to uninoculated controls; bulbs of the variety Red Satan (RS) had the highest enzyme activity. In plants inoculated with S. rolfsii alone, enzyme activity was only increased in bulbs and roots compared to uninoculated controls. The highest levels of enzyme activity also occurred only in bulbs and roots of plants that had been dual-inoculated with T. asperellum and S. rolfsii. Plants of the RS variety showed the highest enzyme activities (both constitutive and induced) and showed the lowest severity of disease. Therefore, application of T. asperellum has potential as a biological control alternative to synthetic fungicides for protection of onion crops against infection by S. rolfsii. This protection depends on both constitutive and induced defence responses and varies amongst onion varieties.     

Effects of dietary exposure to brominated flame retardant BDE-47 on thyroid condition, gonadal development and growth of zebrafish

Little is known about the effects of brominated flame retardants in teleosts and some of the information currently available is inconsistent. This study examined effects of dietary exposure to 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) on thyroid condition, body mass and size, and gonadal development of zebrafish. Pubertal, 49-day-old (posthatch) fish were fed diets without BDE-47 (control) or with 1, 5 or 25 μg/g BDE-47/diet. Treatments were conducted in triplicate 30-L tanks each containing 50 zebrafish, and 15 fish per treatment (5 per tank) were sampled at days 40, 80 and 120 of exposure. Measurements were taken of body mass, standard length, head depth and head length. Sex (at 40–120 days of exposure), germ cell stage (at 40 days) and thyroid condition (at 120 days; follicular cell height, colloid depletion, angiogenesis) were histologically determined. Whole-body BDE-47 levels at study completion were within the high end of levels reported in environmentally exposed (wild) fishes. Analysis of variance was used to determine differences among treatments at each sampling time. No effects were observed on thyroid condition or germ cell stage in either sex. Reduced head length was observed in females exposed to BDE-47 at 80 days but not at 40 or 120 days. In males, no apparent effects of BDE-47 were observed at 40 and 80 days, but fish exposed to 25 μg/g had lower body mass at 120 days compared to control fish. These observations suggest that BDE-47 at environmentally relevant whole-body concentrations does not affect thyroid condition or pubertal development of zebrafish but does affect growth during the juvenile-to-adult transition, especially in males.