Decay of Thermal Tolerance in Queensland Fruit Fly Eggs (Bactrocera tryoni, Diptera: Tephritidae) Following Non-Lethal Heat Hardening.

Quarantine disinfestation treatments for Queensland fruit fly (Bactrocera tryoni (Froggatt)) have been developed which use high temperatures to kill preimaginal life stages within fruit prior to export. However, thermal tolerance of individuals can be increased if they are exposed to elevated temperatures before disinfestation treatment. The rate that this thermal conditioning decays after exposure, and the effect of temperature on this decay process, were investigated. Eggs of B. tryoni were exposed to a nonlethal hot water treatment at 38°C for 15 min, 1 or 3 h, then held in air at 25°C for times ranging from 15 min to 12 h, before being exposed to hot water disinfestation at 46°C for various times. From each of these cohorts, the lethal time for 99% mortality (LT99) was calculated. The LT99 of B. tryoni eggs increased with longer conditioning times at 38°C. For each conditioning time, the LT99 decreased with longer delay periods at 25°C prior to disinfestation. The rate of decrease was greatest during the first hour of delay, after which the rate of decrease slowed and tended toward zero. This induction and decay was modeled using a double-exponential equation. These experiments show that thermal conditions prior to disinfestation, and the time delay before the procedure commences, both influence the response of the insect to the disinfestation treatment. These results have implications for the specification of postharvest quarantine treatments, which are usually expressed only in terms of a fruit-center target temperature.

Irrigation water quality influences heavy metal uptake by willows in biosolids.

Phytoextraction is an effective method to remediate heavy metal contaminated landscapes but is often applied for single metal contaminants. Plants used for phytoextraction may not always be able to grow in drier environments without irrigation. This study investigated if willows (Salix x reichardtii A. Kerner) can be used for phytoextraction of multiple metals in biosolids, an end-product of the wastewater treatment process, and if irrigation with reclaimed and freshwater influences the extraction process. A plantation of willows was established directly onto a tilled stockpile of metal-contaminated biosolids and irrigated with slightly saline reclaimed water (EC ∼2 dS/cm) at a wastewater processing plant in Victoria, Australia. Biomass was harvested annually and analysed for heavy metal content. Phytoextraction of cadmium, copper, nickel and zinc was benchmarked against freshwater irrigated willows. The minimum irrigation rate of 700 mm per growing season was sufficient for willows to grow and extract metals. Increasing irrigation rates produced no differences in total biomass and also no differences in the extraction of heavy metals. The reclaimed water reduced both the salinity and the acidity of the biosolids significantly within the first 12 months after irrigation commenced and after three seasons the salinity of the biosolids had dropped to <15% of initial values. A flushing treatment to remove excess salts was therefore not necessary. Irrigation had an impact on biosolids attributes such as salinity and pH, and that this had an influence on metal extraction. Reclaimed water irrigation reduced the biosolid pH and this was associated with reductions of the extraction of Ni and Zn, it did not influence the extraction of Cu and enhanced the phytoextraction of Cd, which was probably related to the high chloride content of the reclaimed water. Our results demonstrate that flood-irrigation with reclaimed water was a successful treatment to grow willows in a dry climate. However, the reclaimed water can also change biosolids properties, which will influence the effectiveness of willows to extract different metals.

Native Australian species are effective in extracting multiple heavy metals from biosolids.

Selecting native plant species with characteristics suitable for extraction of heavy metals may have multiple advantages over non-native plants. Six Australian perennial woody plant species and one willow were grown in a pot trial in heavy metal-contaminated biosolids and a potting mix. The plants were harvested after fourteen months and above-ground parts were analysed for heavy metal concentrations and total metal contents. All native species were capable of growing in biosolids and extracted heavy metals to varying degrees. No single species was able to accumulate heavy metals at particularly high levels and metal extraction depended upon the bioavailability of the metal in the substrate. Metal extraction efficiency was driven by biomass accumulation, with the species extracting the most metals also having the greatest biomass yield. The study demonstrated that Grevillea robusta, Acacia mearnsii, Eucalyptus polybractea, and E. cladocalyx have the greatest potential as phytoextractor species in the remediation of heavy metal-contaminated biosolids. Species survival and growth were the main determinants of metal extraction efficiency and these traits will be important for future screening of native species.

140 H/D isotopomers identified by long-range NMR hyperfine shifts in ruthenium(III) ammine complexes. Hyperconjugation in Ru-NH3 bonding.

(1)H NMR spectra of the paramagnetic cyanide-bridged mixed-valence compound [(η(5)-C5H5)Fe(CO)2(µ-CN)Ru(NH3)5](CF3SO3)3 (I) have been obtained in several solvents. When traces of partially deuterated water are present, instead of a single cyclopentadienyl (Cp) resonance shifted by the hyperfine interaction, numerous well-resolved resonances are observed. The spectra were simulated satisfactorily by giving the appropriate statistical weight to 140 possible H/D isotopomers formed by deuteration in the five ruthenium(III) ammine ligands. The proliferation of distinct resonances occurs because (a) the hyperfine shifts (HSs) due to each sequential deuteration in a single ammine are different and (b) while deuteration in an ammine cis to the cyanide bridge causes a downfield shift, in the trans ammine it causes an upfield shift that is nearly twice as large. All of these shifts exhibit a 1/T dependence, but temperature-independent components, due to large second-order Zeeman effects at the Ru(III) center, are also present. Combining the results of density functional theory calculations with data from metal-metal charge-transfer optical transitions and with the effect of solvent-induced NMR HSs, it is argued that Fermi contact shifts at the Cp protons are insignificant compared to those due to the dipolar (pseudocontact) mechanism. Analytical expressions are presented for the dependence of the HS on the tetragonal component of the ligand field at the Ru(III) ion. The tetragonal field parameter, defined as the energy by which the 4d(xy) orbital exceeds the mean t(2g) orbital energy, was found to be 147, 52, and 76 cm(-1), in dimethylformamide, acetone, and nitromethane, respectively. The effects of deuteration show that there is a significant component of hyperconjugation in the Ru-ammine interaction and that ND3 is a weaker π donor than NH3. A single deuteration in an axial ammine increases the tetragonal field parameter (ν) by +2.8 cm(-1), resulting in a HS of -37 ppb in the Cp proton resonance, whereas a single deuteration in an equatorial ammine decreases the field by -1.5 cm(-1) with a HS of +20 ppb, despite a nominal separation of seven chemical bonds. We analyze the origin of this remarkable sensitivity, which relies on the favorable characteristics of the Ru(III) low-spin t(2g)(5) configuration, having a spin-orbit coupling constant ζ ≈ 950 cm(-1).

Effect of plants on the bioavailability of metals and other chemical properties of biosolids in a column study.

The effects of metal-accumulating plants (Salix x reichardtii and Populus balsamifera) on the chemical properties and dynamics of metals in biosolids were investigated using different techniques including diffusive gradients in thin films (DGT), sequential extraction procedures and partitioning coefficient (K(d)). Plants could effectively extract Cd, Ni, and Zn and decreased dissolved organic carbon (DOC). The presence of plants increased the potential bioavailability of these metals, as assessed by an increase in the ratio of metal measured by DGT and metals in the solution. The plants affected the Cd, Ni, and Zn pools (soluble/exchangeable; Fe/Mn oxide and organic matter bound) characterised by sequential extraction and K(d) but did not reduce the total metals in either substrate. However, plants had no effect on Cu, presumably because of the effective buffering of available Cu by organic matter in both solution and solid phases. A high density of plant roots was associated with increased leaching of metals.

Phytoextraction of heavy metals by willows growing in biosolids under field conditions.

Biosolids produced by sewage treatment facilities can exceed guideline thresholds for contaminant elements. Phytoextraction is one technique with the potential to reduce these elements allowing reuse of the biosolids as a soil amendment. In this field trial, cuttings of seven species/cultivars of Salix(willows) were planted directly into soil and into biosolids to identify their suitability for decontaminating biosolids. Trees were irrigated and harvested each year for three consecutive years. Harvested biomass was weighed and analyzed for the contaminant elements: As, Cd, Cu, Cr, Hg, Pb, Ni, and Zn. All Salix cultivars, except S. chilensis, growing in soils produced 10 to 20 t ha(-1) of biomass, whereas most Salix cultivars growing in biosolids produced significantly less biomass (<6 t ha(-1)). Salix matsudana (30 t ha(-1)) and S. × reichardtii A. Kerner (18 t ha(-1)) had similar aboveground biomass production in both soil and biosolids. These were also the most successful cultivars in extracting metals from biosolids, driven by superior biomass increases and not high tissue concentrations. The willows were effectual in extracting the most soluble/exchangeable metals (Cd, 0.18; Ni, 0.40; and Zn, 11.66 kg ha(-1)), whereas Cr and Cu were extracted to a lesser degree (0.02 and 0.11 kg ha(-1)). Low bioavailable elements, As, Hg, and Pb, were not detectable in any of the aboveground biomass of the willows.

Effects of phytoextraction on heavy metal concentrations and pH of pore-water of biosolids determined using an in situ sampling technique.

Heavy metal concentrations and pH of pore-water in contaminated substrates are important factors in controlling metal uptake by plants. We investigated the effects of phytoextraction on these properties in the solution phase of biosolids and diluted biosolids in a 12-month phytoextraction column experiment. Phytoextraction using Salix and Populus spp. temporarily decreased pore-water pH of the substrates over the experimental period followed by a return to initial pH conditions. Salixxreichardtii and Populus balsamifera effectively extracted Ni, Zn and Cd and actively mobilized these metals from the solid to the solution phase. S.xreichardtii had the stronger effect on mobilization of metals due to its larger root system. Phytoextraction did not affect Cu in the solution phase of the biosolids. Heavy metals were leached down to lower depths of the columns during the phytoextraction process.

Cyanide (13)C NMR hyperfine shifts in paramagnetic cyanide-bridged mixed-valence complexes.

Paramagnetic (hyperfine) NMR shifts in the (13)C cyanide bridge and (31)P resonances in a set of mixed valence complexes [(eta(5)-C(5)R(5))Ru(PPh(3))L((13)CN)Ru(NH(3))(5)](n+) (R = H; L = PPh(3), CO, NO(+); R = Me; L = PPh(3)) are sensitive to the extent of intermetallic charge-transfer, and are strongly solvent dependent.

Complications of outpatient transbrachial intraarterial digital subtraction angiography. Work in progress.

To assess the safety of nonselective intraarterial digital subtraction angiography (DSA) performed from a brachial artery approach, the complications of 660 consecutive examinations, most of which (greater than 95%) were performed on outpatients, were studied. Contrast material injections into the aorta were made through a 4-F multiple side-hole pigtail catheter inserted percutaneously from the brachial artery. Two brachial artery complications severe enough to require surgery occurred (one hematoma and one arterial laceration/thrombosis), for a rate of 0.3%. No cerebrovascular complications were encountered. Delayed and minor complications were retrospectively studied in 137 patients; they included local arm pain in 24 patients (17.5%), transient paresthesia in ten (7.3%), ecchymosis in 69 (50.4%), and hematoma in 13 (9.5%). The transbrachial approach to nonselective intraarterial DSA is a safe alternative to the femoral artery approach.