Occurrence of oestrogenic pollutants and widespread feminisation of male tilapia in peri-urban dams in Bulawayo,Zimbabwe

Peri-urban water bodies are at risk from excessive pollution as they are direct sinks for urban effluents. The occurrence of oestrogenic and androgenic endocrine disrupting chemicals (EDCs) in effluents and water bodies around the city of Bulawayo, Zimbabwe, and their effects on wild fish was investigated in 2013. Effluent and water were sampled from sewage treatment plants, an urban stream, and effluent-polluted dams, and were compared with a ‘pristine’ dam upstream of Bulawayo. Organic pollutants were extracted by solid-phase extraction and tested for EDCs using a yeast oestrogen/androgen screen. Oestrogenic and androgenic potencies were expressed as 17β-oestradiol equivalent (EEq) or dihydrotestosterone equivalent (TEq). Tilapia and catfish from the dams were analysed for gonado-somatic indices and testis histopathology. Effluents from STPs, which directly flow into Umguza Dam, had EEq of 33 ng l^?1 and 55 ng l^?1, respectively. Umguza Dam, Khami Dam and Matsheumhlope Stream had EEqs of 237 ng l^–1, 9 ng l^?1 and 2 ng l^?1, respectively. Androgenic activity was detected in only one STP (TEq = 93 ng l^?1). Tilapia sampled from effluent-polluted dams had high incidences of testis-ova, but catfish had no signs of reproductive dysfunction. These findings underscore the need for greater attention to EDCs in developing countries where there is scant literature regarding their occurrence and impacts.     

The Reproductive Biology and Reproductive Success of Pterocarpus macrocarpus Kurz1

The reproductive biology of Pterocarpus macrocarpus Kurz (pradu) was studied in 37‐year‐old plantation trees in Thailand to determine the causes of seed and fruit loss. Trees flowered at the end of March or early in April at the end of the hot dry season and start of the rainy season. Flowering occurred over about a one‐month period. Fruits developed over the next six months during the rainy season and matured at the start of the cool dry season in October and November. Phenology was similar in the four trees that were studied in detail. Racemes averaged 30 flowers each and each raceme was receptive for several days, although each flower was only receptive for one day. After pollination, floral parts were shed over several days and fruits began to develop. Pradu is entomopholous but its insect pollinators were not identified. The stigma is covered by hairs and a secretion is produced. A high proportion of flowers were pollinated. Then, there was a rapid loss of flowers and young fruits. These observations and earlier genetic studies indicate the probability of a high level of self‐incompatibility in this predominantly outbreeding species. Pradu may have a very late‐acting self‐incompatibility mechanism found in many other hardwoods. The zygote remains quiescent for six weeks as the endosperm develops. During this time most of the ovules and fruits abort, suggesting resource allocation preferentially to cross‐pollinated ovules. Pradu has a high reproductive potential but a low preemergence reproductive success (0.8), which is common for many hardwood species. The major cause of the low reproductive success was fruit loss during early development. Fruit production may be enhanced by increased cross‐pollination among unrelated parent trees. This may be accomplished in seed orchards and seed production areas by the introduction of additional insect pollinators that travel greater distances between trees and by the relatively close spacing of unrelated parent trees.     

Endocrine disruption in aquatic systems: up‐scaling research to address ecological consequences

Endocrine‐disrupting chemicals (EDCs) can alter biological function in organisms at environmentally relevant concentrations and are a significant threat to aquatic biodiversity, but there is little understanding of exposure consequences for populations, communities and ecosystems. The pervasive nature of EDCs within aquatic environments and their multiple sub‐lethal effects make assessments of their impact especially important but also highly challenging. Herein, we review the data on EDC effects in aquatic systems focusing on studies assessing populations and ecosystems, and including how biotic and abiotic processes may affect, and be affected by, responses to EDCs. Recent research indicates a significant influence of behavioural responses (e.g. enhancing feeding rates), transgenerational effects and trophic cascades in the ecological consequences of EDC exposure. In addition, interactions between EDCs and other chemical, physical and biological factors generate uncertainty in our understanding of the ecological effects of EDCs within aquatic ecosystems. We illustrate how effect thresholds for EDCs generated from individual‐based experimental bioassays of the types commonly applied using chemical test guidelines [e.g. Organisation for Economic Co‐operation and Development (OECD)] may not necessarily reflect the hazards associated with endocrine disruption. We argue that improved risk assessment for EDCs in aquatic ecosystems urgently requires more ecologically oriented research as well as field‐based assessments at population‐, community‐ and food‐web levels.     

Predicting the Effects of Endocrine Disrupting Chemicals on Fish Populations

This study evaluates the applicability and sensitivity of fish population dynamics modeling in assessing the potential effects of individual chemicals on population sustainability and recovery. Fish reproductive health is an increasingly important issue for ecological risk assessment following international concern over endocrine disruption. Life-history data from natural brook trout and fathead minnow populations were combined with effects data from laboratory-based studies, mainly concerning species other than brook trout and fathead minnows, to assess the likely impact of nonylphenol (NP) and methoxychlor (MXC) on brook trout (Salvelinus fontinalis) and fathead minnow (Pimephales promelas) population size. A delay differential equation (DDE) model with a 1-day timestep was used to predict the population dynamics of the brook trout and fathead minnows. The model predicts that NP, could enhance populations by up to 17% at a concentration of 30?µg l^?1 based on the results of reduction in survival and increased fecundity from life-cycle toxicity tests, however attempting to allow for growth reduction and its effect on fecundity results in a prediction of a 28% reduction in population numbers. For fathead minnows the DDE model predicts that the same concentration of NP could cause a population reduction of 21%. The differences in these predictions are related to these two species having different life history strategies, which are considered in the parameterization of the model. Post-application concentrations of MXC may peak around 300?µg l^?1 and then decline rapidly with time. Predictions show that such applications could cause a reduction of up to 30% in brook trout populations if the application occurs at the peak of the spawning season on successive years but that the effect would be less than 1% if the spawning season is avoided. Effects on the fathead minnow population size are predicted to be smaller (<4%) even if application occurs during the spawning period. Risk based statistics generated by the population dynamics models, such as interval decline risk or quasiextinction risk and predicted time to recovery complement traditional effects parameters such as LC50 and LOEC and may ultimately prove to be more useful in risk assessment.     

Endocrine disruption in juvenile roach from English rivers: a preliminary study

Juvenile roach Rutilus rutilus from seven rivers of varying water quality were examined for evidence of endocrine disruption. The majority of roach from five of these rivers had female‐like reproductive ducts. The results suggest that juvenile, rather than adult, fish could be used in studies of endocrine disruption in wild fish populations.     

Molecular mechanism(s) of endocrine‐disrupting chemicals and their potent oestrogenicity in diverse cells and tissues that express oestrogen receptors

Endocrine‐disrupting chemicals (EDCs) are natural or synthetic compounds present in the environment which can interfere with hormone synthesis and normal physiological functions of male and female reproductive organs. Most EDCs tend to bind to steroid hormone receptors including the oestrogen receptor (ER), progesterone receptor (PR) and androgen receptor (AR). As EDCs disrupt the actions of endogenous hormones, they may induce abnormal reproduction, stimulation of cancer growth, dysfunction of neuronal and immune system. Although EDCs represent a significant public health concern, there are no standard methods to determine effect of EDCs on human beings. The mechanisms underlying adverse actions of EDC exposure are not clearly understood. In this review, we highlighted the toxicology of EDCs and its effect on human health, including reproductive development in males and females as shown in in vitro and in vivo models. In addition, this review brings attention to the toxicity of EDCs via interaction of genomic and non‐genomic signalling pathways through hormone receptors.     

Analyses of Sexual Reproductive Success in Transgenic and/or Mutant Plants

The pistil, the female reproductive organ of plants, is a key player in the success of sexual plant reproduction. Ultimately, the production of fruits and seeds depends on the proper pistil development and function. Therefore, the identification and characterization of pistil expressed genes is essential for a better understanding and manipulation of the plant reproduction process. For studying the function of pistil expressed genes, transgenic and/or mutant plants for the genes of interest are used. The present article provides a review of methods already exploited to analyze sexual reproductive success. We intend to supply useful information and to guide future experiments in the study of genes affecting pistil development and function.     

Evaluating the utility of an accelerometer and urinary hormone analysis as indicators of estrus in a Zoo-housed koala (Phascolarctos cinereus)

Induced ovulators, such as the koala, do not always have overt signs of estrus, which makes pairing these animals for breeding purposes difficult to achieve in a zoo setting. This study examined the possibility of using alternative methods to behavioral sampling and weight fluctuations for monitoring estrus in a female koala of reproductive age. We attempt to gain an improved understanding of koala estrus and enhance our ability to detect it by combining a noninvasive technique for hormone analysis with a newer method for recording activity level. The findings suggest that activity levels were accurately measured using an accelerometer and increased activity was associated with one estrus behavior, bellowing. Weekly weight declines occur with increases in activity registered from the accelerometer. We also validated an assay to detect progesterone and estradiol in female koala urine in an attempt to detect an estrus spike. However, neither urinary concentrations of estradiol nor progesterone was associated with behavioral cues of estrus in our subject. We suggest that increased female activity, bellowing, and weight loss all indicate a pro-estrus state that requires proper male stimulation in order to achieve a full estrus display. Zoo Biol 28:59–68, 2009. ©2008 Wiley-Liss, Inc.     

Analyses of Sexual Reproductive Success in Transgenic and/or Mutant Plants

The pistil, the female reproductive organ of plants, is a key player in the success of sexual plant reproduction. Ultimately, the production of fruits and seeds depends on the proper pistil development and function. Therefore, the identification and characterization of pistil expressed genes is essential for a better understanding and manipulation of the plant reproduction process. For studying the function of pistil expressed genes, transgenic and/or mutant plants for the genes of interest are used. The present article provides a review of methods already exploited to analyze sexual reproductive success. We intend to supply useful information and to guide future experiments in the study of genes affecting pistil development and function.     

DDT对火腿伪镖水蚤（Pseudodiaptomus poplesia）急性和慢性毒性效应

为探讨内分泌干扰物DDT对海洋桡足类生物所产生的生物效应,研究了DDT对火腿伪镖水蚤(Pseudodiaptomus poplesia)的急性毒性作用及其在3.5、35、350ng.L-1浓度下对火腿伪镖水蚤变态率、存活率、繁殖力、性别比和体长的影响。结果表明:DDT对火腿伪镖水蚤48hLC50和96hLC50分别为6.75和3.53μg.L-1;各浓度DDT均引起火腿伪镖水蚤幼体变态率的降低;350ng.L-1DDT条件下,火腿伪镖水蚤的存活率、产卵率和抱卵雌体比率均显著降低;各浓度DDT对火腿伪镖水蚤的性别比和体长均未造成显著影响。依据本研究结果,结合目前所报道的近岸水体有机氯农药的污染状况,可以推断,DDT对近海桡足类生物造成的生态风险较高。     

Reproductive biology and implications for management of the spangled emperor Lethrinus nebulosus in the southern Arabian Gulf

The reproductive biology of the spangled emperor Lethrinus nebulosus in the southern Arabian Gulf was determined from the examination of 781 individuals collected between September 2008 and August 2009. There was no histological evidence of adult sex change, and sex ratios did not differ significantly from unity across all size and age classes. Testes had an ovarian structure and a remnant lumen which was not used for sperm transport; furthermore, residual oocytes were observed in the testes of some immature, resting and developing males. A dramatic change in the sex ratio of the smallest and youngest size and age classes suggested that juvenile female to male sex change occurred between 21·0 cm fork length (L(F)) and 24·0 cm L(F) at 1 year of age. The combination of histological evidence with the sexual composition of the size and age structures suggests a non-functional protogynous hermaphroditic sexual pattern, which is analogous to functional gonochorism. The spawning season was well defined, occurring once a year during March, April and early May. Peaks in spawning occurred after full moons, there was a cessation in spawning activity after new moons and spawning was completed within three lunar cycles. The distribution of males over the entire size and age ranges and the absence of inactive mature females during the spawning season suggested that the population was not constrained by sperm limitation. Size-specific and age-specific reproductive potential indicated that conventional regulations that equate the mean size at first capture to sexual maturation are unsuitable for the management of L. nebulosus. The maximum recorded age (11 years), small mean size and young age at sexual maturation (L(m50) = 26·7 cm L(F), 2·1 years, for females and 19·4 cm L(F), 0·5 years, for males) may be a direct result of intensive demersal fishing in the southern Arabian Gulf.     

Reproductive biology and implications for management of the painted sweetlips Diagramma pictum in the southern Arabian Gulf

The reproductive biology of the painted sweetlips Diagramma pictum was determined from 487 individuals collected between January and December 2010 in the southern Arabian Gulf. There was no evidence of sex change and the combination of histological results with the sex composition of the size and age structures indicated a gonochoristic sexual pattern. There were peaks in gonado-somatic indices for females in March and October with spawning occurring during two seasons (April to May and November). The mean size and age at sexual maturity (L(m50) and A(m50) ) were 35·7 cm fork length (L(F) ) and 2·9 years for females and 26·7 cm L(F) and 0·5 years for males. The maximum recorded age (11 years) and small mean size and young age at sexual maturity for males may be a direct result of intensive demersal fishing in the southern Arabian Gulf. There was an exponential increase in the cumulative reproductive potential with size and a linear increase with age for both sexes. The mean L(F) (L(c50) ) at which D. pictum became vulnerable to capture was 33·3 cm, which corresponded to only 3 and 7% of the cumulative reproductive potential of males and females, respectively. Size-specific and age-specific reproductive potential indicated that conventional regulations that equate the mean size at first capture to sexual maturation are unsuitable for the management of D. pictum.     

The use of meta-analysis in food contact materials risk assessment

Abstract

As materials intended to be brought into contact with food, food contact materials (FCMs) – including plastics, paper or inks – can transfer their constituents to food under normal or foreseeable use, including direct or indirect food contact. The safety of FCMs in the EU is evaluated by the European Food Safety Authority (EFSA) using risk assessment rules. Results of independent, health-based chemical risk assessments are crucial for the decision-making process to authorize the use of substances in FCMs. However, the risk assessment approach used in the EU has several shortcomings that need to be improved in order to ensure consumer health protection from exposure arising from FCMs. This article presents the use of meta-analysis as a useful tool in chronic risk assessment for substances migrating from FCMs. Meta-analysis can be used for the review and summary of research of FCMs safety in order to provide a more accurate assessment of the impact of exposure with increased statistical power, thus providing more reliable data for risk assessment. The article explains a common methodology of conducting a meta-analysis based on meta-analysis of the dose-effect relationship of cadmium for benchmark dose evaluations performed by EFSA.     

Influence of Compatibility System and Life Form on Plant Reproductive Success

Abstract: We studied the compatibility system and the autonomous selfing capacity of 32 native species from the Chaco Serrano forests (central Argentina), and compared fruit set, considering plant life form and compatibility status to evaluate: (i) the extent of the association between life form and compatibility system, (ii) the influence of the life form and/or of the compatibility system on natural fruit set, and (iii) the preemergent reproductive advantages provided by self-compatibility and autonomous self-pollination. Ca. 60 % of the species were self-compatible (SC). Natural fruit set of SC species triplicate those of self-incompatible (SI) species. Almost all SC species have autonomous selfing capacity. Nevertheless, on average, SC species produce more than twice as many fruits through natural pollination in comparison to autonomous selfing, and fruit set obtained after autonomous selfing was significantly lower than hand-selfed fruit set. Most SC species received insufficient pollen from themselves via autonomous selfing, and natural fruit set was mostly pollinator-mediated. Thus, the reproductive assurance provided by autonomous selfing is relatively low in comparison with that provided by pollinators. We supplemented our data with published results from different sites in South America, to assess how general are the associations between life form and compatibility system and between natural fruit production and the self compatibility index. There is a differential distribution of SC and SI species according to life form, with a skew towards incompatibility among woody plants and towards compatibility in herbs. On the other hand, regression analysis showed there is a general positive trend between natural fruit set and the self compatibility index of the species.     

Determining Indicators of Exposure and Effects for Endocrine Disrupting Chemicals (EDCs): An Introduction

Endocrine disruptors are characterized by their influence on animal endocrine systems resulting in reproductive, developmental, neurological, and immune dysfunction. The purpose of this overview is to provide the reader with a sense of the activities within the U.S. Environmental Protection Agency (USEPA), in particular NHEERL, that address the many facets of research on endocrine disrupting chemicals (EDCs) and to highlight the approach being taken at the different organizational levels within the USEPA, including screening, testing and evaluating endocrine disrupting chemicals. As a part of this endeavor, the USEPA continues to evaluate the current research activities in order to better understand and refine the process of risk characterization of EDCs. Thus, the participants in this session were asked to review their research within the framework of a better identification of EDC effects, better characterization of those compounds that have endocrine disrupting activity and how to incorporate this information into the risk assessment paradigm. Specifically, the goals of the ensuing papers were to compare individual vs. population indicators of endocrine disrupting effects, examine comparable and multiple mechanisms of toxicity, and describe the use of effects as indicators to identify toxicants and their sources. Mammalian and fish reproductive endpoints served as models to emphasize commonalities between human and wildlife risks.     

Environmentally Contingent Reproductive Strategies in Mayan and Ache Males

This research explores male reproductive parameters, particularly the timing of first reproduction, in two traditional populations. Predictions are drawn from theoretical arguments that have their roots in evolutionary psychology and behavioral ecology, and that interpret variation in reproductive outcomes as environmentally contingent adaptations. In both Ache and Mayan samples, father absence, predicted to act as a stressor that causes precocious sexuality and reproduction as well as unstable pair bonds, did not affect the timing of first reproduction in male offspring in the expected way. Father absence in Mayan men, however, was found to be associated with responses to questionnaire items indicating lack of willingness to pay time and energy costs to maintain existing sexual unions. The results suggest that father absence affects male mating strategy, but that strategic differences did not translate into reproductive outcomes in the sample. In the Mayan population, education was associated with early reproduction, more lifetime sex partners, and higher fertility, which was also contrary to the predicted pattern based on a life-history tradeoff approach. Parental resources were associated with earlier reproduction in the Mayan sample, confirming the prediction that restricted resources should delay reproduction.     

The multigenerational effects of water contamination and endocrine disrupting chemicals on the fitness of Drosophila melanogaster

Water pollution due to human activities produces sedimentation, excessive nutrients, and toxic chemicals, and this, in turn, has an effect on the normal endocrine functioning of living beings. Overall, water pollution may affect some components of the fitness of organisms (e.g., developmental time and fertility). Some toxic compounds found in polluted waters are known as endocrine disruptors (ED), and among these are nonhalogenated phenolic chemicals such as bisphenol A and nonylphenol. To evaluate the effect of nonhalogenated phenolic chemicals on the endocrine system, we subjected two generations (F0 and F1) of Drosophila melanogaster to different concentrations of ED. Specifically, treatments involved wastewater, which had the highest level of ED (bisphenol A and nonylphenol) and treated wastewater from a constructed Heliconia psittacorum wetland with horizontal subsurface water flow (He); the treated wastewater was the treatment with the lowest level of ED. We evaluated the development time from egg to pupa and from pupa to adult as well as fertility. The results show that for individuals exposed to treated wastewater, the developmental time from egg to pupae was shorter in individuals of the F1 generation than in the F0 generation. Additionally, the time from pupae to adult was longer for flies growing in the H. psittacorum treated wastewater. Furthermore, fertility was lower in the F1 generation than in the F0 generation. Although different concentrations of bisphenol A and nonylphenol had no significant effect on the components of fitness of D. melanogaster (developmental time and fertility), there was a trend across generations, likely as a result of selection imposed on the flies. It is possible that the flies developed different strategies to avoid the effects of the various environmental stressors.     

Endocrine and behavioral correlates of drought in wild olive baboons (Papio anubis)

As part of a long-term study in behavioral endocrinology, wild olive baboons (Papio anubis) living in the Serengeti ecosystem of East Africa have been under study since 1978. The present report documents behavioral and endocrine changes associated with the severe drought of 1984. During this time, the annual rainy season failed and grassland biomass was severely reduced in the Serengeti. Baboons were able to maintain body weight but spent significantly more time foraging for food. In four prior years of study, basal testosterone concentrations were remarkably stable in adult and subadult males. In contrast, during the drought, there was a highly significant 60% decline in basal concentrations of the steroid. This testicular suppression was apparent in males of all ranks (by approach-avoidance criteria). Prior studies with this population, which examined the role of acute and chronic stressors in similarly suppressing testosterone concentrations, suggested that the present instance was in response to the stress of the drought. The drought was also associated with significant reductions in the rates of escalated aggression among males. However, the distribution of fights between high-ranking males, between low-ranking males, and between high- and low-ranking males did not change from prior years, nor was the dominance hierarchy inordinately unstable during this time. These findings agree with previous evidence that indicates that suppressed testosterone concentrations in males can be associated with lower rates of aggressive behaviors but that the steroid plays a predominantly facilitative rather than activational role. Finally, rates of approach-avoidance interactions and of male sexual behaviors were unchanged during the drought. These findings agree with an endocrine literature that indicates that reproductive behavior or physiology in primates is rarely disrupted by suppression of testosterone concentrations of the magnitude of the present case.