Soybean Seed Sugars: A Role in the Mechanism of Resistance to Charcoal Rot and Potential Use as Biomarkers in Selection.

Charcoal rot, caused by Macrophomina phaseolina, is a major soybean disease resulting in significant yield loss and poor seed quality. Currently, no resistant soybean cultivar is available in the market and resistance mechanisms to charcoal rot are unknown, although the disease is believed to infect plants from infected soil through the roots by unknown toxin-mediated mechanisms. The objective of this research was to investigate the association between seed sugars (sucrose, raffinose, stachyose, glucose, and fructose) and their role as biomarkers in the soybean defense mechanism in the moderately resistant (MR) and susceptible (S) genotypes to charcoal rot. Seven MR and six S genotypes were grown under irrigated (IR) and non-irrigated (NIR) conditions. A two-year field experiment was conducted in 2012 and 2013 at Jackson, TN, USA. The main findings in this research were that MR genotypes generally had the ability to maintain higher seed levels of sucrose, glucose, and fructose than did S genotypes. Conversely, susceptible genotypes showed a higher level of stachyose and lower levels of sucrose, glucose, and fructose. This was observed in 6 out of 7 MR genotypes and in 4 out of 6 S genotypes in 2012; and in 5 out of 7 MR genotypes and in 5 out of 6 S genotypes in 2013. The response of S genotypes with higher levels of stachyose and lower sucrose, glucose, and fructose, compared with those of MR genotypes, may indicate the possible role of these sugars in a defense mechanism against charcoal rot. It also indicates that nutrient pathways in MR genotypes allowed for a higher influx of nutritious sugars (sucrose, glucose, and fructose) than did S genotypes, suggesting these sugars as potential biomarkers for selecting MR soybean plants after harvest. This research provides new knowledge on seed sugars and helps in understanding the impact of charcoal rot on seed sugars in moderately resistant and susceptible genotypes.

Field studies on the deterioration of microplastic films from ultra-thin compostable bags in soil.

In recent years, some countries have replaced single-use plastic bags with bags manufactured from compostable plastic film that can be used for collecting food wastes and composted together with the waste. Because industrial compost contains undeteriorated fragments of these bags, application to field soil is a potential source of small-sized residues from these bags. This study was undertaken to examine deterioration of these compostable film microplastics (CFMPs) in field soil at three different localities in Italy. Deterioration of CFMPs did not exceed 5.7% surface area reduction during the 12-month experimental period in two sites located in Northern Italy. More deterioration was observed in the Southern site, with 7.2% surface area reduction. Deterioration was significantly increased when fields were amended with industrial compost (up to 9.6%), but not with home compost. Up to 92.9% of the recovered CFMPs were associated with the soil fungus Aspergillus flavus, with 20.1%-71.2% aflatoxin-producing isolates. Application of industrial compost resulted in a significant increase in the percentage of CFMPs associated with A. flavus. This observation provides an argument for government regulation of accumulation of CFMPs and elevation of hazardous fungi levels in agricultural soils that receive industrial compost.

Effects of Charcoal Rot on Soybean Seed Composition in Soybean Genotypes That Differ in Charcoal Rot Resistance under Irrigated and Non-Irrigated Conditions.

Charcoal rot is a major disease of soybean (Glycine max) caused by Macrophomina phaseolina and results in significant loss in yield and seed quality. The effects of charcoal rot on seed composition (seed protein, oil, and fatty acids), a component of seed quality, is not well understood. Therefore, the objective of this research was to investigate the impact of charcoal rot on seed protein, oil, and fatty acids in different soybean genotypes differing in their charcoal rot susceptibility under irrigated and non-irrigated conditions. Two field experiments were conducted in 2012 and 2013 in Jackson, TN, USA. Thirteen genotypes differing in charcoal rot resistance (moderately resistant and susceptible) were evaluated. Under non-irrigated conditions, moderately resistant genotypes showed either no change or increased protein and oleic acid but had lower linolenic acid. Under non-irrigated conditions, most of the susceptible genotypes showed lower protein and linolenic acid but higher oleic acid. Most of the moderately resistant genotypes had higher protein than susceptible genotypes under irrigated and non-irrigated conditions but lower oil than susceptible genotypes. The different responses among genotypes for protein, oil, oleic acid, and linolenic acid observed in each year may be due to both genotype tolerance to drought and environmental conditions, especially heat differences in each year (2012 was warmer than 2013). This research showed that the increases in protein and oleic acid and the decrease in linolenic acid may be a possible physiological mechanism underlying the plant's responses to the charcoal rot infection. This research further helps scientists understand the impact of irrigated and non-irrigated conditions on seed nutrition changes, using resistant and susceptible genotypes.

Persistence in soil of microplastic films from ultra-thin compostable plastic bags and implications on soil Aspergillus flavus population.

An increasing number of states and municipalities are choosing to reduce plastic litter by replacing plastic items, particularly single-use ones, with same-use products manufactured from compostable plastics. This study investigated the formation and persistence of compostable film microplastic particles (CFMPs) from ultra-thin compostable carrier bags in soil under laboratory conditions, and the potential impact of CFMPs on Aspergillus flavus populations in the soil. During a 12-month incubation period, compostable film samples in soils with small, medium or large populations of indigenous A. flavus, underwent 5.9, 9.8, and 17.1% reduction in total surface area, respectively. Despite the low levels of deterioration, the number of CFMPs released increased steadily over the incubation period, particularly fragments with size < 0.05 mm. Up to 88.4% of the released fragments had associated A. flavus and up to 68% of isolates from CFMPs produced aflatoxins. A. flavus levels associated with CFMPs increased rapidly during the initial part of the 12-month incubation period, whereas the percent aflatoxigenicity continued to increase even after A. flavus density leveled off later. During 12 months incubation, A. flavus DNA amounts recovered from CFMPs increased in soils with all levels of indigenous A. flavus, with the largest increases (119.1%) occurring in soil containing the lowest indigenous A. flavus. These results suggest that burying compostable film in soil, or application of compost containing CFMPs, may reduce soil quality and increase risk of adverse impacts from elevated aflatoxigenic A. flavus populations in soil.

Toxin Production in Soybean (Glycine max L.) Plants with Charcoal Rot Disease and by Macrophomina phaseolina, the Fungus that Causes the Disease.

Charcoal rot disease, caused by the fungus Macrophomina phaseolina, results in major economic losses in soybean production in southern USA. M. phaseolina has been proposed to use the toxin (-)-botryodiplodin in its root infection mechanism to create a necrotic zone in root tissue through which fungal hyphae can readily enter the plant. The majority (51.4%) of M. phaseolina isolates from plants with charcoal rot disease produced a wide range of (-)-botryodiplodin concentrations in a culture medium (0.14-6.11 µg/mL), 37.8% produced traces below the limit of quantification (0.01 µg/mL), and 10.8% produced no detectable (-)-botryodiplodin. Some culture media with traces or no (-)-botryodiplodin were nevertheless strongly phytotoxic in soybean leaf disc cultures, consistent with the production of another unidentified toxin(s). Widely ranging (-)-botryodiplodin levels (traces to 3.14 µg/g) were also observed in the roots, but not in the aerial parts, of soybean plants naturally infected with charcoal rot disease. This is the first report of (-)-botryodiplodin in plant tissues naturally infected with charcoal rot disease. No phaseolinone was detected in M. phaseolina culture media or naturally infected soybean tissues. These results are consistent with (-)-botryodiplodin playing a role in the pathology of some, but not all, M. phaseolina isolates from soybeans with charcoal rot disease in southern USA.

Degradation of microplastic seed film-coating fragments in soil.

Encapsulating fungicides and/or insecticides in film-coatings applied to agronomic seeds has become a widely accepted method for enhancing seed germination and overall seedling health by protecting against many diseases and early-season insect pests. Despite advancements in seed film-coating technologies, abrasion of the seed coating can occur during handling and mechanical planting operations, resulting in variable amounts of detached fragments entering the soil. The present study investigated the degradation in soil of these plastic-like, small-sized fragments, referred to here as microplastic coating fragments. Degradation of microplastic coating fragments in soil was found to be highly variable. The lowest degradation rate (≤48 days) was observed in fragments detached from seeds coated with a commercial polymer mixture, while fragments from a biodegradable plastic formulation degraded completely within 32 days. When spores of the plant growth-promoting bacterium, Bacillus subtilis, were incorporated into the bioplastic, degradation was even more rapid (≤24 days). The fragment degradation rate was unaffected by incorporating two commonly used neonicotinoid insecticides, imidacloprid or thiacloprid, into either coating formulations, but insecticide dissipation rates in soil were more rapid when added associated with seed coating fragments than when spiked in directly. Half-lives of these two insecticides were reduced by up to 27% in fragments from bioplastic-coated seeds. These results are consistent with variable and not easily predicted soil degradation rates for seed coating fragments, with enhanced dissipation of coating-entrapped pesticides and with a higher degradation rate for biodegradable seed coating incorporating selected microbial strains.

Laboratory and Field Investigations on Compatibility of Beauveria bassiana (Hypocreales: Clavicipitaceae) Spores With a Sprayable Bioplastic Formulation for Application in the Biocontrol of Tarnished Plant Bug in Cotton.

Two isolates of Beauveria bassiana (Balsamo) Vuillemin, including the commercial strain GHA and the Mississippi Delta native NI8 strain, and two emulsifiers, Tween-80 and a starch-based sprayable bioplastic, were evaluated in the laboratory and field for pathogenicity and infectivity against the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Heteroptera: Miridae). The effect on fruit damage based on within-season cotton plant mapping was also examined. The highest mortality 10 d after treatment was found with insects caged on cotton terminals sprayed with NI8 + Tween-80, followed by those exposed to NI8 + bioplastic. Similarly, sporulation was shown to be higher in NI8 + Tween-80 than in other treatments. Plots sprayed with B. bassiana showed at least a twofold decrease in tarnished plant bug adults 3 d after treatment compared with control plots. Little to no variation was observed in tarnished plant bug nymph populations between treated and untreated plots. Within-season plant mapping provided clear evidence of damage to cotton caused by tarnished plant bug. The highest percentage retention of all first position fruiting structures was observed in plots treated with NI8 + Tween-80 (93.41 ± 1.51) followed by NI8 + bioplastic (90.25 ± 1.52). Both treatments were significantly different when compared with GHA + Tween-80 (82.89 ± 2.26) and GHA + bioplastic (70.48 ± 3.19), and both GHA formulations did not differ from the control (63.61 ± 2.96). Overall, these results indicated that B. bassiana application resulted in >50% mortality of tarnished plant bug regardless of the isolates by direct spray or by contact. However, the superior performance of the Mississippi Delta native NI8 strain was observed in all treatment applications and evaluation times.

Biological Control of Aflatoxin Contamination in U.S. Crops and the Use of Bioplastic Formulations of Aspergillus flavus Biocontrol Strains To Optimize Application Strategies.

Aflatoxin contamination has a major economic impact on crop production in the southern United States. Reduction of aflatoxin contamination in harvested crops has been achieved by applying nonaflatoxigenic biocontrol Aspergillus flavus strains that can out-compete wild aflatoxigenic A. flavus, reducing their numbers at the site of application. Currently, the standard method for applying biocontrol A. flavus strains to soil is using a nutrient-supplying carrier (e.g., pearled barley for Afla-Guard). Granules of Bioplastic (partially acetylated corn starch) have been investigated as an alternative nutritive carrier for biocontrol agents. Bioplastic granules have also been used to prepare a sprayable biocontrol formulation that gives effective reduction of aflatoxin contamination in harvested corn kernels with application of much smaller amounts to leaves later in the growing season. The ultimate goal of biocontrol research is to produce biocontrol systems that can be applied to crops only when long-range weather forecasting indicates they will be needed.

Leaf application of a sprayable bioplastic-based formulation of biocontrol Aspergillus flavus strains for reduction of aflatoxins in corn.

BACKGROUND: Applying non-aflatoxin-producing Aspergillus flavus isolates to the soil has been shown to be effective in reducing aflatoxin levels in harvested crops, including peanuts, cotton and corn. The aim of this study was to evaluate the possibility of controlling aflatoxin contamination using a novel sprayable formulation consisting of a partially gelatinized starch-based bioplastic dispersion embedded with spores of biocontrol A. flavus strains, which is applied to the leaf surfaces of corn plants. RESULTS: The formulation was shown to be adherent, resulting in colonization of leaf surfaces with the biocontrol strain of A. flavus, and to reduce aflatoxin contamination of harvested kernels by up to 80% in Northern Italy and by up to 89% in the Mississippi Delta. The percentage of aflatoxin-producing isolates in the soil reservoir under leaf-treated corn was not significantly changed, even when the soil was amended with additional A. flavus as a model of changes to the soil reservoir that occur in no-till agriculture. CONCLUSIONS: This study indicated that it is not necessary to treat the soil reservoir in order to achieve effective biocontrol of aflatoxin contamination in kernel corn. Spraying this novel bioplastic-based formulation to leaves can be an effective alternative in the biocontrol of A. flavus in corn. © 2015 Society of Chemical Industry.

Implications of Bt traits on mycotoxin contamination in maize: Overview and recent experimental results in southern United States.

Mycotoxin contamination levels in maize kernels are controlled by a complex set of factors including insect pressure, fungal inoculum potential, and environmental conditions that are difficult to predict. Methods are becoming available to control mycotoxin-producing fungi in preharvest crops, including Bt expression, biocontrol, and host plant resistance. Initial reports in the United States and other countries have associated Bt expression with reduced fumonisin, deoxynivalenol, and zearalenone contamination and, to a lesser extent, reduced aflatoxin contamination in harvested maize kernels. However, subsequent field results have been inconsistent, confirming that fumonisin contamination can be reduced by Bt expression, but the effect on aflatoxin is, at present, inconclusive. New maize hybrids have been introduced with increased spectra of insect control and higher levels of Bt expression that may provide important tools for mycotoxin reduction and increased yield due to reduced insect feeding, particularly if used together with biocontrol and host plant resistance.

Implications of European corn borer, Ostrinia nubilalis, infestation in an Aspergillus flavus-biocontrolled corn agroecosystem.

BACKGROUND: A novel biocontrol strategy consisting of field application of bioplastic-based granules inoculated with a non-toxigenic Aspergillus flavus L. strain has recently been shown to be effective for reducing aflatoxin contamination in corn. This study focused on other factors that may affect the feasibility of this biocontrol technique, and more specifically the role of the European corn borer (ECB), Ostrinia nubilalis H., in the dispersal and infestation of A. flavus in corn and its impact on crop yield. RESULTS: In spite of the high percentage of corn ears showing larval feeding damage, ECB-bored kernels accounted for only 3 and 4% in 2009 and 2010 respectively. Most of the damaged kernels were localised in the ear tip or immediately below. More precisely, the average incidence of ECB-bored kernels in the upper end of the ear was 32%. However, less than 5% of kernels from the central body of the ear, which includes the majority of kernels, were injured by ECB. CONCLUSIONS: Although ECB larvae showed a high tolerance to aflatoxin B1 and thus had the potential to serve as vectors of the mould, fungal infection of kernels was poorly associated with insect damage. ECB infestation resulted in grain yield losses not exceeding 2.5%.

Application of bioplastic moving bed biofilm carriers for the removal of synthetic pollutants from wastewater.

In this series of laboratory experiments, the feasibility of using moving bed biofilm carriers (MBBC) manufactured from existing bioplastic-based products for the removal of bisphenol A, oseltamivir, and atrazine from wastewater was evaluated. After 10-d incubation, cumulative evolution of (14)CO(2) from control (no MBBC) wastewater spiked with (14)C-labeled bisphenol A, oseltamivir or atrazine, accounted for approximately 18%, 7% and 3.5% of the total added radioactivity, respectively. When wastewater samples were incubated with freely moving carriers, greater removal of the three chemicals was observed. More specifically, cumulative (14)CO(2) evolution of the three xenobiotics increased of 34%, 49%, and 66%, with respect to the control, respectively. Removal efficiency of MBBC was significantly increased by inoculating these bioplastic carriers with bioremediation bacterial strains. Results from this study suggest that the concept behind the moving bed biofilm reactor technology can also be extended to biodegradable carriers inoculated with bioremediation microorganisms.

Deterioration of bioplastic carrier bags in the environment and assessment of a new recycling alternative.

Increasing environmental concerns and the introduction of technologies based on renewable resources have stimulated the replacement of persistent petroleum-derived plastics with biodegradable plastics from biopolymers. As a consequence, a variety of products are currently manufactured from bioplastic, including carrier bags. This series of studies investigated the deterioration of carrier bags made with Mater-Bi (MB), a starch-based bioplastic, in soil, compost and two aquatic ecosystems, a littoral marsh and seawater. Results from the laboratory study indicated that bioplastic carrier bags were rapidly deteriorated in soil and compost. After three months of incubation, weight loss of specimens was of 37% and 43% in soil and compost, respectively. Conversely, little deterioration was observed in specimens buried in soil under field conditions or exposed to water of a littoral marsh and of the Adriatic Sea. These findings were consistent with the greater number of bacteria and especially fungi capable of degrading MB that were recovered from soil and compost with respect to the two aquatic ecosystems. Considering that a variety of microbial isolates are capable of using MB as a source of carbon, a new alternative to recycle these MB-based carrier bags was explored. More specifically, starchy residues from bags were fermented by the fungus Rhizopus oryzae to produce up to 35 mg of lactic acid per g of bag residues.

Removal of oseltamivir (Tamiflu) and other selected pharmaceuticals from wastewater using a granular bioplastic formulation entrapping propagules of Phanerochaete chrysosporium.

The capacity of the ligninolytic fungus Phanerochaete chrysosporium to degrade a wide variety of environmentally persistent xenobiotics has been largely reported in the literature. Beside other factors, one barrier to a wider use of this bioremediation fungus is the availability of effective formulations that ensure easy preparation, handling and application. In this series of laboratory experiments, we evaluated the efficiency of a granular bioplastic formulation entrapping propagules of P. chrysosporium for removal of four selected pharmaceuticals from wastewater samples. Addition of inoculated granules to samples of the wastewater treatment plant of Bologna significantly increased the removal of the antiviral drug oseltamivir (Tamiflu), and the antibiotics, erythromycin, sulfamethoxazol, and ciprofloxacin. Similar effects were also observed in effluent water. Oseltamivir was the most persistent of the four active substances. After 30d of incubation, approximately two times more oseltamivir was removed in bioremediated wastewater than controls. The highest removal efficiency of the bioplastic formulation was observed with the antibiotic ciprofloxacin. Microbiological DNA-based analysis showed that the bioplastic matrix supported the growth of P. chrysosporium, thus facilitating its adaptation to unusual environment such as wastewater.

Dissipation and removal of oseltamivir (Tamiflu) in different aquatic environments.

The antiviral drug oseltamivir (Tamiflu) has received recent attention due to the potential use as a first-line defense against H5N1 and H1N1 influenza viruses. Research has shown that oseltamivir is not removed during conventional wastewater treatments, thus having the potential to enter surface water bodies. A series of laboratory experiments investigated the fate and the removal of oseltamivir in two surface water ecosystems of Japan and in a municipal wastewater treatment plant located in Northern Italy. Persistence of oseltamivir in surface water ranged from non-detectable degradation to a half-life of 53d. After 40d, <3% of radiolabeled oseltamivir evolved as (14)CO(2). The presence of sediments (5%) led to a significant increase of oseltamivir degradation and mineralization rates. A more intense mineralization was observed in samples of the wastewater treatment plant when applying a long incubation period (40d). More precisely, 76% and 37% of the initial radioactivity applied as (14)C-oseltamivir was recovered as (14)CO(2) from samples of the biological tank and effluent water, respectively. Two bacterial strains growing on oseltamivir as sole carbon source were isolated and used for its removal from synthetic medium and environmental samples, including surface water and wastewater. Inoculation of water and wastewater samples with the two oseltamivir-degrading strains showed that mineralization of oseltamivir was significantly higher in both inoculated water and wastewater, than in uninoculated controls. Denaturing gradient gel electrophoresis and quantitative PCR analysis showed that Tamiflu would not affect the microbial population of surface water and wastewater.

Soil depth and tillage effects on glyphosate degradation.

The use of glyphosate-resistant crops facilitated the widespread adoption of no-tillage (NT) cropping systems. The experimental objectives were to determine glyphosate sorption, mineralization, and persistence at two depths [0-2 cm (A) and 2-10 cm (B)] in a silt loam managed under long-term conventional tillage (CT) or NT soybean. Relative to the other soils, organic carbon (OC) and fluorescein diacetate (FDA) hydrolytic activity were at least 1.4-fold higher in NT-A. Glyphosate K(d) values ranged from 78.2 to 48.1 and were not correlated with OC. Cumulative glyphosate mineralized after 35 days was highest in NT-A soil (70%), intermediate in CT-A and CT-B (63%), and least in NT-B (51%). Mineralization was positively correlated with OC and FDA activity, but negatively correlated with K(d), indicating that sorption decreased bioavailability. Independent of tillage and depth, the half-lives for 0.01 N CaCl(2) and 0.1 N NaOH extractable residues (bioavailable residues and residues bound to iron and aluminum oxides, respectively) were

Use of a granular bioplastic formulation for carrying conidia of a non-aflatoxigenic strain of Aspergillus flavus.

Previous research demonstrated that aflatoxin contamination in corn is reduced by field application of wheat grains pre-inoculated with the non-aflatoxigenic Aspergillus flavus strain NRRL 30797. To facilitate field applications of this biocontrol isolate, a series of laboratory studies were conducted on the reliability and efficiency of replacing wheat grains with the novel bioplastic formulation Mater-Bi to serve as a carrier matrix to formulate this fungus. Mater-Bi granules were inoculated with a conidial suspension of NRRL 30797 to achieve a final cell density of approximately log 7 conidia/granule. Incubation of 20-g soil samples receiving a single Mater-Bi granule for 60-days resulted in log 4.2-5.3 propagules of A. flavus/g soil in microbiologically active and sterilized soil, respectively. Increasing the number of granules had no effect on the degree of soil colonization by the biocontrol fungus. In addition to the maintenance of rapid vegetative growth and colonization of soil samples, the bioplastic formulation was highly stable, indicating that Mater-Bi is a suitable substitute for biocontrol applications of A. flavus NRRL 30797.

Bromoxynil degradation in a Mississippi silt loam soil.

BACKGROUND: The objectives of these laboratory experiments were: (1) to assess bromoxynil sorption, mineralization, bound residue formation and extractable residue persistence in a Dundee silt loam collected from 0-2 cm and 2-10 cm depths under continuous conventional tillage and no-tillage; (2) to assess the effects of autoclaving on bromoxynil mineralization and bound residue formation; (3) to determine the partitioning of non-extractable residues; and (4) to ascertain the effects of bromoxynil concentration on extractable and bound residues and metabolite formation. RESULTS: Bromoxynil K(d) values ranged from 0.7 to 1.4 L kg(-1) and were positively correlated with soil organic carbon. Cumulative mineralization (38.5% +/- 1.5), bound residue formation (46.5% +/- 0.5) and persistence of extractable residues (T(1/2) < 1 day) in non-autoclaved soils were independent of tillage and depth. Autoclaving decreased mineralization and bound residue formation 257-fold and 6.0-fold respectively. Bromoxynil persistence in soil was rate independent (T(1/2) < 1 day), and the majority of non-extractable residues (87%) were associated with the humic acid fraction of soil organic matter. CONCLUSIONS: Irrespective of tillage or depth, bromoxynil half-life in native soil is less than 1 day owing to rapid incorporation of the herbicide into non-extractable residues. Bound residue formation is governed principally by biochemical metabolite formation and primarily associated with soil humic acids that are moderately bioavailable for mineralization. These data indicate that the risk of off-site transport of bromoxynil residues is low owing to rapid incorporation into non-extractable residues.

Environmental fate of the antiviral drug Tamiflu in two aquatic ecosystems.

The antiviral drug Tamiflu (Oseltamivir Phosphate, OP), has been indicated by the World Health Organization as a first-line defense in case of an avian influenza pandemic. Recent studies have demonstrated that Oseltamivir Carboxylate (OC), the active metabolite of the prodrug OP, has the potential to be released into water bodies. The present laboratory study focused on basic processes governing the environmental fate of OC in surface water from two contrasting aquatic ecosystems of northern Italy, the River Po and the Venice lagoon. Results of this study confirmed the potential of OC to persist in surface water. However, addition of 5% of sediments resulted in rapid OC degradation. Estimated half-life of OC in water/sediment of the River Po was 15 days. After three weeks of incubation at 20 degrees C, more than 8% of (14)C-OC evolved as (14)CO(2) from water/sediment samples of the River Po and Venice lagoon. At the end of the 21-day incubation period, more than 65% of the (14)C-residues were recovered from the liquid phase of both Po and Venice water/sediment samples. OC was moderately retained onto coarse sediments from the two sites. In water/sediment samples of the River Po and Venice lagoon treated with (14)C-OC, more than 30% of the (14)C-residues remained water-extractable after three weeks of incubation. The low affinity of OC to sediments suggests that presence of sediments would not reduce its bioavailability to microbial degradation.

Meeting report: risk assessment of tamiflu use under pandemic conditions.

On 3 October 2007, 40 participants with diverse expertise attended the workshop Tamiflu and the Environment: Implications of Use under Pandemic Conditions to assess the potential human health impact and environmental hazards associated with use of Tamiflu during an influenza pandemic. Based on the identification and risk-ranking of knowledge gaps, the consensus was that oseltamivir ethylester-phosphate (OE-P) and oseltamivir carboxylate (OC) were unlikely to pose an ecotoxicologic hazard to freshwater organisms. OC in river water might hasten the generation of OC-resistance in wildfowl, but this possibility seems less likely than the potential disruption that could be posed by OC and other pharmaceuticals to the operation of sewage treatment plants. The work-group members agreed on the following research priorities: a) available data on the ecotoxicology of OE-P and OC should be published; b) risk should be assessed for OC-contaminated river water generating OC-resistant viruses in wildfowl; c) sewage treatment plant functioning due to microbial inhibition by neuraminidase inhibitors and other antimicrobials used during a pandemic should be investigated; and d) realistic worst-case exposure scenarios should be developed. Additional modeling would be useful to identify localized areas within river catchments that might be prone to high pharmaceutical concentrations in sewage treatment plant effluent. Ongoing seasonal use of Tamiflu in Japan offers opportunities for researchers to assess how much OC enters and persists in the aquatic environment.