Reproduction, larval growth, and reproductive development in African clawed frogs (Xenopus laevis) exposed to atrazine

Reproductive success and development of F2 offspring from F1 adult African clawed frogs (Xenopus laevis) exposed to atrazine throughout larval development and as sexually mature adults was examined. Larval X. laevis were exposed to one of four nominal concentrations of atrazine (0, 1, 10, 25 microg atrazine/l) beginning 96 hr after fertilization and continuing through two years post-metamorphosis. Clutch size and survival of offspring were used as measurement endpoints to gauge reproductive success of the F1 frogs. Larval survivorship and time to metamorphosis were used to gauge developmental success of the F2 offspring from atrazine-exposed frogs. Testes in F1 and F2 frogs were examined for incidence of anomalies, such as testicular ovarian follicles, and sex ratios in F2 offspring were investigated to determine if exposure to atrazine caused trans-generational effects (effects on F2 individuals due to exposure of F1 individuals). There were no effects of any of the studied concentrations of atrazine on clutch size of F1 frogs. There were also no effects on hatching success or time to metamorphosis. Sex ratios did not differ between F2 offspring among treatments. There was no evidence to suggest a transgenerational effect of atrazine on spawning success or reproductive development of X. laevis. This is consistent with the presence of robust populations of X. laevis in areas where they are exposed to atrazine that has been used for several decades for weed control in production of corn. Our observations also are consistent with the results of most other studies of frogs where no effects were found to be associated with exposure to atrazine. Our data do not support the hypothesis that atrazine significantly affects reproductive fitness and development of frogs.     

Mortality of the scleractinian coral <Emphasis Type="Italic">Cladocora caespitosa</Emphasis> during a warming event in the Levantine Sea (Cyprus)

A mortality event of Cladocora caespitosa corals and the extent of bleaching, necrosis and pigmented areas in the colonies were studied at the southeastern coast of Cyprus during a prolonged period of higher than average sea temperature anomalies (summer/autumn 2012). With the use of scuba diving and image analysis software, we monitored the extent of mortality of 29 colonies of C. caespitosa by measuring and comparing the area percentage of healthy tissue, affected tissue (bleached, necrotic) and older mortality events (encrusted skeleton). In September 2012, on average, 24 % of the colonies surface area was affected (bleaching and/or necrosis). In October 2012, C. caespitosa showed on average 26.3 % of the colony surface area affected, evidence of continuing deterioration. At the same time, 10 % (3 of 29) of the colonies showed an increase in the pigmentation of previously bleached polyps in small and marginal areas (6–8 %). Irrespective of the amount, the regaining of pigments recorded is considered an important find. Corals and marine organisms in general in the Levantine Sea are affected greatly by warming events, to the extent where a very small percentage of polyps/colonies show resilience under thermal stress. Natural bleaching of C. caespitosa, even though limited to a few colonies and very small portions of tissue/polyps, was documented for the first time in the Levantine Sea. We conclude that temperature anomalies are associated with the mortality event. Whether prolonged higher temperature is the direct cause, or whether it acts synergistically with other factors should be the subject of further investigations.     

Assessment of compost quality for its environmentally safe use by means of an ecotoxicological test on a soil organism

A research project was carried out to evaluate toxicological effects of compost addition to agricultural soil using the earthworm Eisenia foetida (Annellida) as a representative organism of the soil fauna. Moreover, the correlation between compost biochemical stabilization and toxicity at different phases of the composting process was assessed. Samples were collected from three composting plants at three different maturation levels (beginning of the composting process, intermediate compost after bio-oxidation, and mature refined compost). Two tests were performed: a standard chronic solid-phase test and an acute solid-phase test (developed originally by the authors). In the first test, the measured end-points were mortality, growth and reproduction; while in the second test earthworms’ behavior was evaluated. The chosen compost concentrations in soil ranged from 2.5 to 100 %, with the aim of obtaining the toxicological parameters (LC50) and to mimic real agricultural dosages for the lower concentrations. Results indicated an increase in compost toxicity with greater compost concentrations; in particular, agricultural compost dosage below 10 % showed no toxicity. Moreover, toxicity did not decrease during composting; intermediate compost showed the highest LC50 values. As a consequence, no correlation was ascertained between the results of ecotoxicological analysis and waste biochemical stability parameters during the composting process.     

Variation patterns in individual fish responses to chemical stress among estuaries, seasons and genders: the case of the European flounder (Platichthys flesus) in the Bay of Biscay

The objective was to describe and model variation patterns in individual fish responses to contaminants among estuaries, season and gender. Two hundred twenty-seven adult European flounders were collected in two seasons (winter and summer) in four estuaries along the Bay of Biscay (South West France), focusing on a pristine system (the Ster), vs. three estuaries displaying contrasted levels of contaminants (the Vilaine, Loire and Gironde). Twenty-three variables were measured by fish, considering the load of contaminants (liver metals, liver and muscle persistent organic pollutants, muscle polycyclic aromatic hydrocarbons); the gene expression (Cyt C oxydase, ATPase, BHMT, Cyt P450 1A1, ferritin); the blood genotoxicity (Comet test); and liver histology (foci of cellular alteration–tumour, steatosis, inflammation, abnormal glycogen storage). Canonical redundancy analysis (RDA) was used to model these variables using gender, season and estuary of origin as explanatory variables. The results underlined the homogeneity of fish responses within the pristine site (Ster) and more important seasonal variability within the three contaminated systems. The complete model RDA was significant and explained 35 % of total variance. Estuary and season respectively explained 30 and 5 % of the total independent variation components, whilst gender was not a significant factor. The first axis of the RDA explains nearly 27 % of the total variance and mostly represents a gradient of contamination. The links between the load of contaminants, the expression of several genes and the biomarkers were analysed considering different levels of chemical stress and a possible multi-stress, particularly in the Vilaine estuary.     

Heavy metals and couple fecundity, the LIFE Study

The effect of heavy metals at environmentally relevant concentrations on couple fecundity has received limited study despite ubiquitous exposure. In 2005-2009, couples (n = 501) desiring pregnancy and discontinuing contraception were recruited and asked to complete interviews and to provide blood specimens for the quantification of cadmium (μg L⁻¹), lead (μg dL⁻¹) and mercury (μg L⁻¹) using inductively coupled plasma-mass spectrometry. Couples completed daily journals on lifestyle and intercourse along with menstruation and pregnancy testing for women. Couples were followed for 12 months or until pregnant. Fecundability odds ratios (FORs) and 95% confidence intervals (CIs) were estimated adjusting for age, body mass index, cotinine, and serum lipids in relation to female then male exposures. FORs <1 denote a longer time to pregnancy. In adjusted models, reduced FORs were observed for both female cadmium (0.78; 95% CI 0.63-0.97) and male lead (0.85; 95% CI 0.73-0.98) concentrations. When jointly modeling couples’ exposures, only male lead concentration significantly reduced the FOR (0.82; 95% CI 0.68, 0.97), though the FOR remained <1 for female cadmium (0.80; 95% CI 0.64, 1.00). This prospective couple based cohort with longitudinal capture of time to pregnancy is suggestive of cadmium and lead’s reproductive toxicity at environmentally relevant concentrations.     

Risk and opportunity in upgrading the US drinking water infrastructure system

This paper presents a practical risk assessment methodology to provide drinking water infrastructure (DWI) decision-makers with an objective risk assessment tool. The purpose of this risk assessment tool is to maintain the desired level-of-service or systems reliability [r(f)], while managing the financial uncertainty of the expected budgetary impact within the capital improvement program (CIP). The goal of this paper is to demonstrate the value of an objective risk assessment tool for estimating the DWI decision-maker's sensitivity to the risk of systems failure (R). The objectives are to: (1) incorporate probability of systems failure [p(f)] into the CIP budgetary analysis process and (2) evaluate the affects of p(f) on the expected CIP budgetary outcome. The magnitude of the expected budgetary impact is managed through the DWI decision-maker's sensitivity to R, which is represented by the level of the rate of reinvestment (RR). The expected result of the proposed risk assessment tool demonstrates that by proactively managing R to maintain a desired r(f) will effectively manage the impact of uncertainty on the expected budgetary outcome within the CIP. The expected contribution of the practical risk assessment methodology is to provide DWI decision-makers with the ability to reduce budgetary uncertainty when allocating limited financial resources among competing operational, repair, maintenance, and expansion activities within the CIP. The conclusions of the paper reveal that if DWI decision-makers assume risk-avoidance positions through proactive asset management (AM) strategies, they will achieve positive affects on expected budgetary outcomes.     

Cytogenetic analysis of Oedalechilus labeo (Pisces: Mugilidae), with a report of NOR variability

 A cytogenetic analysis by several staining techniques was carried out on Oedalechilus labeo specimens from the west coast of Italy, in order to extend the karyological knowledge on Mediterranean mullets. The karyotype of the species is composed of 46 acrocentric and 2 subtelocentric chromosomes. Constitutive heterochromatin was found to be restricted to the centromeres. Fluorochrome staining revealed a uniform base composition along the chromosome arms. Nucleolus organizer regions (NORs) are located on the short arms of chromosome pair 9 and can be either homomorphic or quite heteromorphic in size. In some specimens chromomycin A₃-staining and fluorescence in situ hybridization with 18S rDNA revealed a third additional and inactive NOR on the short arms of a medium-sized chromosome. This is the first report of NOR variability in Mugilidae, a family generally characterized by a quite conservative karyotype. Heterochromatin composition and NOR location differentiate O. labeo from a cytotaxonomical point of view from the Liza species studied, Liza being considered the genus from which the genus Oedalechilus derived. Received: 10 April 1999 / Accepted: 21 October 1999     

Local Irrigation Management Institutions Mediate Changes Driven by External Policy and Market Pressures in Nepal and Thailand

This article assesses the role of local institutions in managing irrigation water use. Fifty irrigation systems in each country were studied in Nepal and Thailand to compare the influence of local institutions on performance of irrigation systems amid changes in external policy and market pressures. Nepal’s new irrigation policy after the re-instatement of multiparty democracy in 1990 emphasized participatory irrigation management transferring the management responsibility from state authorities to water users. The water user associations of traditional farmer-managed irrigation systems were formally recognized by requiring registration with related state authorities. In Thailand also government policies encouraged people’s participation in irrigation management. Today water users are directly involved in management of even some large irrigation systems at the level of tertiary canals. Traditional communal irrigation systems in northern Thailand received support for system infrastructure improvement but have faced increased interference from government. In Thailand market development supported diversification in farming practices resulting in increased areas under high water-demanding commercial crops in the dry season. In contrast, the command areas of most irrigation systems in Nepal include cereal-based subsistence farming with only one-third having commercial farming. Cropping intensities are higher in Nepal than in Thailand reflecting, in part, differences in availability of land and management. In both countries local institutions play an important role in maintaining the performance of irrigation systems as external drivers and local contexts change. Local institutions have provided alternative options for irrigation water use by mediating external pressures.     

The internal brain drain: foreign aid,hiring practices,and international migration

Building on empirical material gathered in Haiti, this paper advances a new and innovative understanding of the internal brain drain phenomenon—the poaching of local skilled workers by international organisations (IOs) or international non-governmental organisations (INGOs)— by conceptualising it as an equilibrium. This equilibrium is composed of two sets of tensions: (i) those between the salary conditions in the public sector and those on offer to local personnel working for IOs and INGOs; and (ii) those inherent in the dual salary scale used by IOs and INGOs for local and international staff. These two sets of tensions contribute in their specific ways to international migration, and, as such, the internal brain drain has a bearing on external brain drain dynamics. In addition, the paper addresses the difficult policy choices facing development and humanitarian organisations, since every set of policies that impacts on one side of the equilibrium is bound to affect its other side.