Anaerobic sediment potential acidification and metal release risk assessment by chemical characterization and batch resuspension experiments

Background, Aim and Scope  Sediments act as a sink for toxic substances (heavy metals, organic pollutants) and, consequently, dredged materials often contain pollutants which are above safe limits. In polluted anaerobic sediments, the presence of sulphides and redox potential changes creates a favorable condition for sulphide oxidation to sulphate, resulting in potential toxic metal release. The oxidation reaction is catalyzed by several microorganisms. Some clean up measures, such as dredging, can initiate the process. The aim of the present work is to assess the acidification and metal release risk in the event of sediment dredging and also to compare two different acid base account techniques with the resuspension results. The oxidation mechanism by means of inoculation with an Acidithiobacillus ferrooxidans strain was also evaluated. Methodology  The sediments were chemically characterized (pH; organic oxidizable carbon; acid volatile sulphides; total sulphur; moisture; Cr, Cu and Zn aqua regia contents). A metal sequential extraction procedure (Community Bureau of Reference, BCR technique) was applied to calculate the Acid Producing Potential (APP) and Acid Consuming Capacity (ACC) of the sediment samples through Fe, Ca²⁺ and SO₄ ²⁻ measurements. The acid base account was also performed by the Sobek methodology (Acid producing potential — AP — calculated with total sulphur and neutralization potential — NP — by titration of the remaining acid after a reaction period with the sample). Fresh sediments were placed in agitated shake flasks and samples were taken at different times to evaluate pH, SO₄ ²⁻ and Cr, Cu, Zn and Fe²⁺ concentration. Some of the systems were inoculated with an Acidithiobacillus ferrooxidans strain to assess the biological catalysis on sulphide oxidation. Results  Sediment chemical characterization showed high organic matter content (5.4–10.6%), total sulphur (0.36–0.86%) and equivalent CaCO₃ percentages (4.5–8%). pH was neutral-alkaline for all of the samples. AVS content was high except for sample 5. The acid base account obtained with the two methods gave different results for the acid generating risk of the samples. A decrease of 0.4 to 3.1 pH units was measured in the agitated shake flasks. In all of the systems, sulphate concentration increased (2,100–2,200 mg L⁻¹ to 2,500–3,000 mg L⁻¹), and positively correlated with the initial total sulphur content of the samples in the inoculated flasks. Cu and Cr in solution were not detected in most of the sampling occasions (<0.5 mg Cu L⁻¹ and <0.5 mg Cr L⁻¹). Zn reached high concentrations (up to 11.8 mg L⁻¹). For every system — except sediment 1 — the lowest pH registered was similar in comparison to inoculated and control systems. The inoculation effect was mostly evidenced in the systems by a higher sulphate release rate compared to the control systems. Discussion  The BCR method categorized all of the samples as potentially acid generating material. The Sobek method using NPR (NP/AP) criteria classified sample 3 as a possible acid generator and samples 1, 2 and 5 with a low acid generation potential. Despite this, all the samples acidified the media in the kinetic tests in at least one of the conditions employed in this work. It would seem that NPR and NNP (NP-AP) risk classification criteria should not be directly used with anaerobic sediments. Appropriate classification levels for sediments should be developed considering the different sulphide reactivity between rock and sediments. Sediment oxidation can cause acidification, which is partially explained by sulphide oxidation. In the samples studied, we found a positive correlation between sulphate increase in solution after oxidation and total sulphur content in the inoculated systems. Significant amounts of Zn could be released to solution while Cr and Cu remained insoluble despite the pH decrease observed. The low Cu and Cr mobility could be explained by the very low solubility of their hydroxides and high affinity for organic matter and iron oxides/hydroxides that might form during sediment oxidation. Dredged sediment management and disposal should be carefully planned. Conclusions  All of the sediment samples lowered the pH media in the laboratory batch resuspension experiments. However, both risk classification criteria (NNP, NPR) from Sobek acid base account were not able to predict the samples’ behavior as accurately as the BCR derived base account. The inoculation effect was mostly associated with a higher sulphate release and not to a lower pH due to acid base equilibrium. Recommendations and Perspectives  Appropriate risk classification levels for sediments should be developed considering the different sulphide reactivity between rock and sediments. ESS-Submission Editor: Dr. Sabine Ulrike Gerbersdorf (sug@st-andrews.ac.uk)     

Influence of nitrogen and elemental‐sulfur fertilization on sulfur oxidation and mineralization in relation to soil moisture on a calcareous soil of the Inner Mongolia steppe of China

Grassland‐livestock farming is the main agricultural activity in the Inner Mongolia steppe of China. It has been estimated that more than 80% of the grasslands suffer from sulfur (S) deficiency in this region. In an incubation study and a greenhouse experiment with alfalfa, the influence of soil moisture (40% and 70% water‐holding capacity, WHC), nitrogen (0 and 200 mg N (kg soil)^–1 as NH₄NO₃), and elemental sulfur (eS; 0 and 300 mg S (kg soil)^–1) amendments on the apparent eS oxidation, eS‐oxidation rate, net S‐mineralization rate, and S uptake of alfalfa were studied. After 28 d of incubation, the eS‐oxidation rate was four times higher at 70% than at 40% WHC if no N was applied. With N application, soil moisture had only minor effects on eS oxidation during the whole incubation period. In the greenhouse experiment, lower values for eS‐oxidation rate and net S‐mineralization rate were found if no N was applied. Application of N and eS significantly increased alfalfa growth and S uptake. The results of both experiments suggest that combined N and eS applications are the best way to alleviate S deficiency on these calcareous soils.     

Evaluation of VIE (Visible Implant Elastomer) and PIT (Passive Integrated Transponder) physical tagging systems for the identification of red porgy fingerlings (Pagrus pagrus)

The effect of two physical tagging systems, Visible Implant Elastomer (VIE) and Passive Integrated Transponder (PIT), was evaluated in red porgy (Pagrus pagrus) fingerlings, at different sizes. For VIE tagging, the weight classes were <1 and 1?C5?g and no tag effect was detected on fish growth. There was a significant difference in mortality between tagged and untagged <1?g fish, but not for the 1?C5?g fish. The tag loss rate was null for all sizes, however, tags showed fragmentation. This partial tag loss was evaluated and quantified. Seven VIE colours were compared and arranged from best to worst visibility: green, red, pink, orange, yellow, white and blue. For PIT tagging, 2?C6?g, 5?C10?g and 10?C20?g weight classes were analysed. There was no significant tag effect on fish growth, for any size, nor on mortality from 10?g. Tag loss rate ranged from 2.9 to 5.9%. These results demonstrate that, in red porgy, VIE is a successful tagging system from 2?g onwards whereas PIT system is successful from 10?g onwards. The combination of both systems allows traceability of fish from a very small size on, which is necessary for the implementation of genetic breeding programmes.     

Extraction and HPLC analysis of phenolic compounds in leaves, stalks, and textile fibers of Urtica dioica L

In the present study the phenolic composition of leaves, stalks, and textile fiber extracts from Urtica dioica L. is described. Taking into account the increasing demand for textile products made from natural fibers and the necessity to create sustainable "local" processing chains, an Italian project was funded to evaluate the cultivation of nettle fibers in the region of Tuscany. The leaves of two nettle samples, cultivated and wild (C and W), contain large amounts of chlorogenic and 2- O-caffeoylmalic acid, which represent 71.5 and 76.5% of total phenolics, respectively. Flavonoids are the main class in the stalks: 54.4% of total phenolics in C and 31.2% in W samples. Anthocyanins are second in quantitative importance and are present only in nettle stalks: 28.6% of total phenolics in C and 24.4% in W extracts. Characterization of phenolic compounds in nettle extracts is an important result with regard to the biological properties (antioxidant and antiradical) of these metabolites for their possible applications in various industrial activities, such as food/feed, cosmetics, phytomedicine, and textiles.     

Effect of a single injection of progesterone on ovarian follicular cysts in lactating dairy cows

The objective of this experiment was to evaluate the effect of a single injection of progesterone on the lifespan of ovarian follicular cysts and to examine the fate of follicles that mature following treatment. Lactating Holstein and Jersey cows with ovarian follicular cysts were identified by rectal palpation. The ovaries of cystic cows were then examined by transrectal ultrasonography three times weekly to monitor formation of new follicular cysts. Cows with newly formed follicular cysts were treated either with a single injection of progesterone (200 mg, IM, n = 11) or corn oil vehicle (n = 7). Venous blood samples were collected daily for quantification of progesterone. Blood sampling and ultrasonography continued until ovulation or a new follicular cyst formed. Treatment reduced the lifespan of the cyst by 12 days, from 29.8 +/- 2.3 days in control cows to 17.2 +/- 1.8 days in progesterone-treated cows (P = 0.01). Progesterone treatment also tended to alter the frequency of subsequent follicular events. Ovulation occurred in 4/11 cows that were treated with progesterone whereas none of the vehicle treated cows ovulated (P = 0.07). In conclusion, a single injection of 200mg of progesterone, administered early in the life of an ovarian follicular cyst, shortened its lifespan and in some cases was followed by ovulation of a new follicle.     

Saponins show high entomotoxicity by cell membrane permeation in Lepidoptera

BACKGROUND: In this study, the effects of three saponins and one sapogenin with a triterpenoid or steroid structure in two lepidopteran insect cell lines, ovarian Bm5 and midgut CF‐203 cells, were analysed with regard to cell viability, cell membrane permeation, EcR responsiveness and DNA fragmentation. In addition, the entomotoxic action of Q. saponaria saponin with primary midgut cell cultures and larval stages of the cotton leafworm Spodoptera littoralis was tested. RESULTS: Both lepidopteran cell lines show a high sensitivity to all four sapo(ge)nins, with a concentration‐dependent viability loss and EC₅₀ values of 25–100 µM in MTT bioassays. A trypan blue assay with Q. saponaria saponin confirmed rapid cell membrane permeation to be a cause of cytotoxicity. Saponins caused no EcR activation in Bm5 cells, but a loss of ecdysteroid signalling was observed with IC₅₀ values of 5–10 µM . Lower saponin concentrations induced DNA fragmentation, confirming their potential to induce apoptosis. Finally, Q. saponaria saponin caused cytotoxicity in primary midgut cell cultures of S. littoralis (EC₅₀ = 4.7 µM ) and killed 70–84% of S. littoralis larvae at pupation at 30‐70 mg g^?1, while lower concentrations retarded larval weight gain and development. CONCLUSIONS: The data obtained provide evidence that saponins exert a strong activity on lepidopteran cells, presumably based on a cytotoxic action due to permeation of the cell membrane. Primary midgut cell cultures and larvae of S. littoralis showed high sensitivity to Q. saponaria saponin, indicating the insect midgut as a primary target for entomotoxicity and the potential use of saponins in the control of pest Lepidoptera. Copyright © 2012 Society of Chemical Industry     

Influence of stocking density on the behaviour of juvenile Litopenaeus vannamei (Boone, 1931)

Applied ethology can help to improve Litopenaeus vannamei aquaculture. Our purpose was to demonstrate an influence of stocking density on behaviour. The shrimp were first distributed in aquaria and observed via an ad libitum observational method to construct an ethogram of social and feeding behavioural categories. The resulting ethogram consisted of retreat, cannibalism, getting to the feeding tray, occupying the feeding tray and getting feed. We then kept shrimp in aquaria at densities of 50, 75 and 100 animals m^?2 and observed them via a behavioural sampling method using our ethogram as well as focal animal sampling of behaviours derived from the literature. These literature‐derived behaviours consisted of inactivity, feeding, crawling, exploration, burying, swimming and cleaning. We found that stocking density affects the behaviour of the shrimp. Optimal searching and feeding and a low frequency of crawling and swimming occurred at a density of 50 animals m^?2, indicating a higher potential for growth and welfare at this density.     

The effect of dietary supplementation with globin and spray-dried porcine plasma on performance,digestibility and histomorphological traits in broiler chickens

This study evaluated the effects of globin and spray-dried porcine plasma (SDPP) on growth performance, digestibility, nitrogen retention, energy retention efficiency (ERE) and intestinal morphology of broiler chickens. A total of 336-day-old male broiler chickens were reared from 1 to 40 days of age and fed 3 diets (8 replicates/diet, 14 birds/replicate) during 3 feeding phases: starter (1–12 days), grower (12–25 days) and finisher (25–40 days). Isonitrogenous diets were formulated by replacing gluten protein isolate contained in the control diet (C diet) with 2% (starter) or 1% (grower and finisher) spray-dried porcine plasma in the plasma diet (SDPP diet). The globin diet (G diet) was obtained by adding globin on the top of C diet at a dose of 0.08% for the whole rearing period. Total tract apparent digestibility (aD), nitrogen retention and ERE were assessed during the three growing phases. At 12  and 40 days of age, one bird per pen was slaughtered to sample gut, liver, spleen and bursa of Fabricius for histomorphological investigations. The SDPP diet increased body weights of chickens at 12 (+60 g; p < .001), 25 (+101 g; p < .001) and 40 days (+130 g; p = .018) of age compared to C and G diets. Also SDPP improved crude protein aD (+9.7%) and ERE (+12.3%) during the starter phase (p < .001). Dietary globin and SDPP inclusion did not affect either the gut morphology or the histopathological findings in birds at 12 and 40 days of age, despite a numerical (+6.90% and +7.40% respectively) villus height improvement in the SDPP group. Overall, these results confirm that dietary supplementation with SDPP and, to a lesser extent, with globin can improve growth performance and dietary protein and energy utilization in broiler chickens without effect on gut functionality.     

Seroepidemiology of canine babesiosis and ehrlichiosis in a hospital population

Canine ehrlichiosis and babesiosis have a worldwide distribution with geographic variation in prevalence and main clinical manifestations. We prospectively determined seroprevalence of canine babesiosis and ehrlichiosis, and risk factors for seropositivity. Three hundred and eighty-one dogs were randomly selected to represent the canine population at a Veterinary Teaching Hospital in south Brazil (latitude 23° S). Dogs were tested with a point-of-care ELISA for Ehrlichia canis antibodies and IFA to confirm previous exposure to Babesia vogeli. Multiple logistic regression analysis was then used to estimate adjusted odds ratio (OR) and their 95% confidence intervals. One hundred and thirty-six (36%) dogs were seropositive for B. vogeli antibodies, whereas 87 (23%) dogs were seropositive to E. canis antibodies. Fifty-four (14%) dogs seroreacted to both agents. Adult dogs previously infested with ticks were more likely to seroreact to B. vogeli or E. canis. Superficial bleeding (OR = 12.4) was more common in dogs exposed to B. vogeli, whereas neurological signs (OR = 7.7) were more common in dogs seropositive to E. canis. Neurological signs (OR = 12.0) and lameness (OR = 12.8) were more prevalent in dogs that seroreacted to both organisms. Owners of dogs with ticks were more likely to have been exposed to ticks themselves (OR = 3.2). Canine babesiosis and ehrlichiosis appear to be highly prevalent in this hospital population. Clinical signs differed from the most common signs in other regions with bleeding occurring more in dogs seropositive to babesiosis, but not ehrlichiosis; neurologic signs in dogs with E. canis antibodies; and lameness in dogs that seroreacted to both organisms.     

A comparative study of methods for diagnosis of obesity in an urban mixed-race population in Minas Gerais, Brazil

BACKGROUND: Obesity is defined as an excess of total body fat and may be assessed by different methods. The objective of the present study was to establish the discriminatory power of anthropometric data in determining obesity. METHODS: The subjects comprised 685 individuals, aged 20-79 years, sampled from a population-based survey. The following indicators were used: body mass index (BMI), waist circumference (WC) and total body fat percentage estimated with both Siri's equation (%BF Siri) and foot-to-foot bioelectrical impedance analysis (%BF BIA). Sensitivity and specificity of different cut-off points for each method were determined using %BF BIA as reference. RESULTS: Of 685 participants, 57.6% were aged >/= 40 years, 69.9% were women and 72.6% self-referred themselves as non-white. To classify obesity based on sex and age among women aged 0.05). Classifying according to skin colour did not change cut-off points in any indicator. CONCLUSION: BMI and WC better discriminate obesity among women and men aged >/= 40 years from a mixed-race population.