Effects Of Environmental Contaminants Research Articles

Levels of Cord Blood Lead in Pregnant Women from the Inma-Gipuzkoa Cohort (Basque Country; Spain)

ISEE-0272 Background and Objective: The INMA project (Childhood and Environment) studies the possible effects of environmental contaminants on infant growth and development. Exposure to lead (Pb) during the prenatal period has been associated with adverse effects on fetal development. This study aims to investigate exposure to Pb in 524 children born in Zumarraga hospital (INMA-Gipuzkoa cohort), which serves 25 municipalities in Gipuzkoa (Basque country, Spain). Methods: During 2003–2007, Pb and PM10 levels in the air were measured in urban centres with metallurgical activity and in one municipality without such activity. Cord blood Pb was analysed in 524 children, as an indicator of exposure. The level of Pb in drinking water was analyzed throughout all 25 municipalities. Pb, PM2.5 and PM10 levels were determined using gravimetric analysis and inductively coupled plasma atomic emission spectroscopy. Cord blood Pb was determined using electrothermal atomic absorption. Pb in drinking water was analysed quarterly using graphite furnace atomic absorption spectrophotometry. Results: Only in Zumarraga were atmospheric Pb levels detected that were higher than the limit established by law (0.5 μg/m3) (Mean: 0.5 μg/m3), exceeding the limit on 23.9% of days. Eighty-six percent of drinking water samples presented levels lower than the detection threshold (1 μg/l), with the mean level for all samples at 4.5 μg/l. Ninety-two percent of cord blood samples displayed values lower than the detection threshold (1 μg/l), with a mean level for all samples of 2.6 μg/l. Conclusions: Exposure to lead via air and water, at levels that are below the values required by law, is reflected in low cord blood lead levels in the study area.

Large prospective birth cohort studies on environmental contaminants and child health – Goals, challenges, limitations and needs

The adverse health effects of environmental contaminants (ECs) are a rising public health concern, and a major threat to sustainable socioeconomic development. The developing fetuses and growing children are particularly vulnerable to the adverse effects of ECs. However, assessing the health impact of ECs presents a major challenge, given that multiple outcomes may arise from one exposure, multiple exposures may result in one outcome, and the complex interactions between ECs, and between ECs, nutrients and genetic factors, and the dynamic temporal changes in EC exposures during the life course. Large-scale prospective birth cohort studies collecting extensive data and specimen starting from the prenatal or pre-conception period, although costly, hold promise as a means to more clearly quantify the health effects of ECs, and to unravel the complex interactions between ECs, nutrients and genotypes. A number of such large-scale studies have been launched in some developed counties. We present an overview of "why", "what" and "how" behind these efforts with an objective to uncover major unidentified limitations and needs. Three major limitations were identified: (1) limited data and bio-specimens regarding early life EC exposure assessments in some birth cohort studies; (2) heavy participant burdens in some birth cohort studies may bias participant recruitment, and risk substantial loss to follow-up, protocol deviations limiting the quality of data and specimens collection, with an overall potential bias towards the null effect; (3) lack of concerted efforts in building comparable birth cohorts across countries to take advantage of natural "experiments" (large EC exposure level differences between countries) for more in-depth assessments of dose-response relationships, threshold exposure levels, and positive and negative effect modifiers. Addressing these concerns in current or future large-scale birth cohort studies may help to produce better evidence on the health effects of ECs.

Effects of Environmental Contaminants on Hemoglobin Gene Expression in Daphnia magna: A Potential Biomarker for Freshwater Quality Monitoring

Daphnia hemoglobin (Hb) is one of the widely investigated invertebrate respiratory pigment. In this study, alteration of Daphnia magna Hb was evaluated in terms of its gene expression, using four D. magna Hb open reading frames (ORFs), by exposure of various chemicals, such as nonylphenol (NP), bisphenol A (BPA), benzo[a]pyrene (B[a]P), chloropyriphos (CP), paraquat dichloride (PQ), and lead nitrate (Pb), under laboratory conditions. A Daphnia reproduction test was also conducted to test the ecotoxicological relevance of chemical-induced Daphnia Hb gene expression. Daphnia Hb gene expression increased by most of tested chemicals. Nonylphenol induced all four Hb ORFs, and an increase in D. magna hemoglobin 2 (dmhb2), dmhb3, and dmhb4 gene expression was exposure concentration dependent. Although BPA and B[a]P also induced most of the Hb genes, the degree of increase was less than two-fold compared to the control. For CP and Pb exposure, an increase in dmhb2 and dmhb4 gene expression was the most significant among the four Daphnia Hb ORFs. Each ORF might exhibit different sensitivities to chemical stress; of the four ORFs studied, an increase in dmhb2 and dmhb4 gene expression was the most significant. It seems clear that Daphnia Hb has a considerable potential as a biomarker for freshwater toxicity monitoring, as an increase in Hb gene expression seems to be correlated with a decrease in reproduction in this animal. The results suggest that Daphnia Hb could give useful information to diagnose general health conditions in a freshwater ecosystem. Considering the potential of D. magna as a biomonitoring species and the physiological particularities of its respiratory pigments, Daphnia Hb could be developed as a biomarker for ecotoxicity monitoring.

Pressure Injection of Ilyanassa Snail Embryos

The marine gastropod Ilyanassa obsoleta is a long-standing and very useful model for studies of embryonic development. It is an especially important model for spiralian development, and for studies of asymmetric cell division. The embryos are amenable to classic embryological manipulation techniques, as well as a growing number of molecular approaches. Ilyanassa is also an important model for studies of metamorphosis, the ecology of parasitism, the effects of environmental contaminants on morphology and sexual function, and comparative neurobiology. Intracellular microinjection is an important tool, especially for lineage tracing and perturbations of specific genes by knockdown approaches and synthetic mRNA injections. Two methods for the introduction of lineage tracers into particular cells are routine in Ilyanassa. Iontophoresis of charged molecules, such as fluorophore-dextran conjugates can be accomplished using a simply built current generator. Injection of an oil-based solution containing the fluorescent probe 1,1-dioctadecyl-3,3,3',3'-tetramethyl indocarbocyanine perchlorate (DiI) is also straightforward. However, injection of oil-based solutions and iontophoresis have not been useful for delivering water-soluble reagents to perturb gene function, and pressure injection of aqueous solutions has been more challenging. This protocol describes a recently optimized procedure for the pressure injection of aqueous solutions into Ilyanassa embryos and zygotes with high rates of survival and normal development. The key parameters seem to be the injection needles, injection media, and the stage of injected embryos.

Obtaining Ilyanassa Snail Embryos

The marine gastropod Ilyanassa obsoleta is a long-standing and very useful model for studies of embryonic development. It is an especially important model for spiralian development, and for studies of asymmetric cell division. The embryos are amenable to classic embryological manipulation techniques as well as a growing number of molecular approaches. Ilyanassa is also an important model for studies of metamorphosis, the ecology of parasitism, the effects of environmental contaminants on morphology and sexual function, and comparative neurobiology. Ilyanassa adults are readily obtainable and easy to keep in the laboratory. Although the normal spawning season for Ilyanassa is during early summer, they can produce high-quality embryos nearly year-round in the laboratory. Snails collected in the late fall, winter, or spring can be induced to deposit zygotes before the natural spawning season by warming them to room temperature, and snails collected before the natural spawning season can be made to postpone zygote deposition until needed (up to at least 6 mo) by maintaining them in tanks in a cold room at 4 degrees C-8 degrees C. This protocol describes how to induce embryo production in Ilyanassa snails, collect the embryos, and rear them to the stage required for study.

Isolating Protein from Ilyanassa Snail Embryos

The marine gastropod Ilyanassa obsoleta is a long-standing and very useful model for studies of embryonic development. It is an especially important model for spiralian development, and for studies of asymmetric cell division. The embryos are amenable to classic embryological manipulation techniques as well as a growing number of molecular approaches. Ilyanassa is also an important model for studies of metamorphosis, the ecology of parasitism, the effects of environmental contaminants on morphology and sexual function, and comparative neurobiology. This protocol describes the procedure for extracting protein from Ilyanassa embryos for use in techniques such as Western blotting or two-dimensional (2D) gel electrophoresis.

Fixation of Ilyanassa Snail Embryos and Larvae: Figure 1.

The marine gastropod Ilyanassa obsoleta is a long-standing and very useful model for studies of embryonic development. It is an especially important model for spiralian development, and for studies of asymmetric cell division. The embryos are amenable to classic embryological manipulation techniques, as well as a growing number of molecular approaches. Ilyanassa is also an important model for studies of metamorphosis, the ecology of parasitism, the effects of environmental contaminants on morphology and sexual function, and comparative neurobiology. Ilyanassa embryos are particularly well suited for RNA and protein localization studies because of the relatively large cells and favorable properties for imaging. This protocol describes how to fix and store Ilyanassa embryos and larvae for use in whole-mount in situ hybridization and immunohistochemical studies.

Induction of Larval Metamorphosis in the Snail Ilyanassa: Figure 1.

The marine gastropod Ilyanassa obsoleta is a long-standing and very useful model for studies of embryonic development. It is an especially important model for spiralian development, and for studies of asymmetric cell division. The embryos are amenable to classic embryological manipulation techniques as well as a growing number of molecular approaches. Ilyanassa is also an important model for studies of metamorphosis, the ecology of parasitism, the effects of environmental contaminants on morphology and sexual function, and comparative neurobiology. Ilyanassa adults are readily obtainable and easy to keep in the laboratory, and they can produce high-quality embryos nearly year-round in the laboratory. After hatching from capsules, larval Ilyanassa can be maintained in culture, feeding on single-celled algae. The larvae will become competent to undergo metamorphosis after approximately 3 wk in culture. Metamorphosis can be induced artificially by treating with either the neurotransmitter serotonin or the nitric oxide synthase inhibitor 7-nitroindazole. Both of these reagents have been shown to induce metamorphosis in >75% of larvae within 48 h. This protocol describes the induction of metamorphosis in snail larvae.

Isolation of Genomic DNA from Ilyanassa Snail Larvae

The marine gastropod Ilyanassa obsoleta is a long-standing and very useful model for studies of embryonic development. It is an especially important model for spiralian development, and for studies of asymmetric cell division. The embryos are amenable to classic embryological manipulation techniques as well as a growing number of molecular approaches. Ilyanassa is also an important model for studies of metamorphosis, the ecology of parasitism, the effects of environmental contaminants on morphology and sexual function, and comparative neurobiology. Ilyanassa is host to several species of parasitic trematode worms, so care must be taken to avoid contamination of Ilyanassa genomic DNA with that of the parasites. The easiest way to avoid this contamination is to isolate DNA from veliger larvae, which are not parasitized. This also avoids other problems that can be encountered when isolating DNA from adult mollusc tissues, such as the presence of large amounts of polysaccharides. This protocol describes the isolation of genomic DNA from Ilyanassa larvae.

Novel approaches for the study of vertebrate steroid hormone receptors

Steroid hormones are essential for the normal function of most organ systems in vertebrates. Reproductive activities in females and males, such as the differentiation, growth and maintenance of the reproductive system, require signaling by sex steroid hormones. Although extensively studied in mammals and a few fish and bird species, the evolution and molecular mechanisms associated with the nuclear steroid hormone receptors are still poorly understood in amphibians and reptiles. Given our interest in environmental signaling of sex determination as well as a major interest in environmental contaminants that can mimic steroid hormone signaling, we have established an approach to study the molecular function (ligand binding and trans-activation) of steroid hormone receptors cloned from reptiles. This approach involves molecular cloning and sequencing of steroid hormone receptors, phylogenic analysis and in vitro trans-activation assays using endogenous or exogenous ligands. Comparing the in vitro trans-activation induced by different ligands with receptors cloned from different species would develop additional functional relationships (classification) among steroid hormone receptors. This approach can provide insight into understanding why each species could have different responses to exogenous ligands. Further, we have developed a novel and less invasive approach to obtaining mRNA for molecular cloning and sequencing of steroid hormone receptors in reptiles and other non-mammalian species, using blood cells as a source of genetic material. For example, white blood cells (WBCs) and red blood cells (RBCs) of the American alligator both express steroid hormone receptors and have adequate amounts of mRNA for molecular cloning. This approach would allow us to analyze components of endocrine function of steroid hormones without sacrificing animals. Especially in endangered species, this approach could provide an understanding of endocrine functions, elucidate the phylogenic relationships of various receptors in vitro, such as the steroid hormone receptors, and determine possible effects of environmental contaminants in a minimally invasive manner.

Relative Toxicity of Malathion to Trematode-Infected and Noninfected Rana palustris Tadpoles

Amphibian populations around the world are facing threats that include disease and pollution. Although the effect of environmental contaminants on susceptibility to infection has been demonstrated for several amphibian species, to our knowledge, the opposite interaction, infection status affecting contaminant susceptibility, has not been studied. We conducted standard 48-h toxicity tests to compare susceptibility to malathion, a widely used organophosphate insecticide, of uninfected pickerel frog (Rana palustris) tadpoles and tadpoles infected with two levels (10 or 30 cercariae) of the trematode Echinostoma trivolvis. Trematode encystment rates were high (>90%) in both trematode treatment groups. LC(50) values ranged from 16.5 to 17.4 mg/L, within the range reported for other amphibian species. However, we found no differences in susceptibility to malathion among parasite treatments. Although we detected no effect of parasites on pesticide susceptibility in this system, it is important to investigate this question using other pesticides, parasites, and amphibian hosts before dismissing this potentially threatening interaction.

Effects of environmental contaminants on hemoglobin of larvae of aquatic midge, Chironomus riparius (Diptera: Chironomidae): A potential biomarker for ecotoxicity monitoring

The effects of environmental contaminants (i.e., nonylphenol, bisphenol A diglycidyl ether, benzo[a]pyrene, chlorpyriphos, paraquat dichloride, and lead nitrate) on Chironomus hemoglobin were investigated in the 4th instar larvae of Chironomus riparius (Diptera: Chironomidae), with respect to the total hemoglobin contents, individual globin gene expression, individual globin protein expression and hemoglobin oxidation. In our studies, 7 and 6 globin isoforms were preliminarily characterized by molecular weight and isoelectric point, respectively, in the 4th instar larvae of C. riparius. Most chemicals were unable to modify the total hemoglobin contents, however, the expression patterns of the globin transcript and proteins suggest that C. riparius globin exists in both inducible and consecutively expressed forms, with multiplicity that may allow this animal to better adapt toward stressful environmental conditions, including pollution stress. The oxyhemoglobin was observed to be downregulated in C. riparius on exposure to bisphenol A and chlorpyriphos, probably reflecting its increased autoxidation to methemoglobin. The overall results would suggest that globin can be a target molecule of environmental contaminants, and of the tested parameters, the alteration of individual globin levels (i.e., mRNA or protein levels) may have potential for the development of a biomarker for ecotoxicity monitoring.

Blood, sweat, and tears: Embedding biological samples in social science research on children1,2

In the first decade of the 21st Century, calls for interdisciplinary research are commonplace. Yet, relatively few papers discuss how to complete such research successfully. In this paper, I describe the details of data collection focused on five, six and seven‐year old children. The project examined the effect of environmental contaminants on children's educational outcomes. It included a primary caregiver interview, a skill test with the child, and a venous blood draw from the child to test for lead, mercury, cadmium, arsenic, nicotine, and cotinine. This paper describes key issues and the solutions I adopted. Challenges discussed here include navigating the Institutional Review Board Process, analyzing the blood, obtaining the supplies needed to draw blood, banking blood for future research, hiring a phlebotomist, and recruiting subjects. While not all details will apply directly to other research projects, this paper provides some perspective on the current realities facing social scientists who decide to collect biological samples.

Conservation of threespine and ninespine stickleback radiations in the Cook Inlet Basin, Alaska

Summary Threespine stickleback (Gasterosteus aculeatus) and ninespine stickleback (Pungitius pungitius) are both species complexes with many unique and reproductively isolated biological species throughout their range. Both complexes exhibit phenomenal morphological and ecological diversity, including rare phenotypes, in the Cook Inlet Basin in Southcentral Alaska. The Cook Inlet threespine stickleback radiation has been used intensively since the early 1990s to study the genetic and behavioural mechanisms of rapid evolution and speciation, loss of skeletal elements and armor structures, body shape evolution, evolution of development and developmental abnormalities, behavioural evolution, life history evolution, trophic ecology, parasitism, genetic structure and function, and effects of environmental contaminants. Unique populations from both species complexes should be conserved to protect the scientific investment in these radiations and their future utility for research. Many of these populations are now threatened by invasive northern pike (Esox lucius). Northern pike have already caused the local extinction of a rare, weakly-armored threespine stickleback in Prator Lake, and pike are a potential future threat to threespine stickleback in nearby Bear Paw Lake, the source population for the stickleback genome project. Other threats in the Cook Inlet Basin include salmonid stocking in isolated lakes, human impacts on water quality, water withdrawals for human use, and climate change. These threats should be addressed through targeted pike eradication and educational programs on introduced species, a new lake stocking policy that incorporates stickleback conservation, discontinuation of ichthyocide use, research to improve water quality, restrictions on water withdrawals, and a comprehensive stickleback monitoring program. The goals of these actions should be to secure the future viability of special research populations, as well as the maintenance of phenotypic diversity within both stickleback radiations.

The effect of ambient contamination on PEMFC performance

The effect of environmental contamination (NO x , SO 2) on the performance of proton exchange membrane fuel cells (PEMFC) was studied. The performance of PEMFCs was tested for 100 h with different cathode reactants. According to the Ambient Air Quality Standard of PRC, three kinds of cathode gases were applied to operate the fuel cells, which were 1 ppm NO 2/air, 1 ppm SO 2/air and a mixture of contaminant gases. The gas mixture contained 0.8 ppm NO 2, 0.2 ppm NO and 1 ppm SO 2. Finally, the poisoning behavior and the mechanisms were analyzed by constant-current discharging and cycle voltammetry (CV). During the 100 h test, the potentials of the fuel cell degraded by 65%, 77% and 90% with 1 ppm SO 2/air, a gas mixture and 1 ppm NO 2/air, respectively.

Budburst phenology of white birch in industrially polluted areas

Effects of environmental contamination on plant seasonal development have only rarely been properly documented. Monitoring of leaf growth in mountain birch, Betula pubescens subsp. czerepanovii, around a nickel–copper smelter at Monchegorsk hinted advanced budburst phenology in most polluted sites. However, under laboratory conditions budburst of birch twigs cut in late winter from trees naturally growing around three point polluters (nickel–copper smelter at Monchegorsk, aluminium factory at Kandalaksha, and iron pellet plant at Kostomuksha) showed no relationship with distance from the emission source. In a greenhouse experiment, budburst phenology of mountain birch seedlings grown in unpolluted soil did not depend on seedling origin (from heavily polluted vs. clean sites), whereas seedlings in metal-contaminated soil demonstrated delayed budburst. These results allow to attribute advanced budburst phenology of white birch in severely polluted sites to modified microclimate, rather than to pollution impact on plant physiology or genetics.

Biomarkers of exposure and effects of environmental contaminants on swallows nesting along the Rio Grande, Texas, USA

We collected adult cave swallows (Petrochelidon fulva) and cliff swallows (P. pyrrhonota) during the breeding seasons in 1999 and 2000 from eight locations along the Rio Grande from Brownsville to El Paso (unless otherwise specified, all locations are Texas, USA) and an out-of-basin reference location. Body mass, spleen mass, hepatosomatic index (HSI), gonadosomatic index (GSI), thyroxine (T4) in plasma, DNA damage measured as the half-peak coefficient of variation of DNA content (HPCV) in blood cells, as well as acetylcholinesterase and butyrylcholinesterase in brain were compared with concentrations of organochlorines, metals, and metalloids in carcasses to determine potential effects of contaminants on swallows during the breeding season. Concentrations of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) were significantly greater in swallows from El Paso than in those from most locations, except for Pharr and Llano Grande. All swallows from these three locations had p,p'-DDE concentrations of 3 microg/g wet weight or greater. Swallows from El Paso either had or shared the highest concentrations of p,p'-DDE, polychlorinated biphenyls, and 13 inorganic elements. Swallows from El Paso exhibited greater spleen mass and HPCV values as well as lower T4 values compared with those from other locations. Thyroxine was a potential biomarker of contaminant exposure in swallows of the Rio Grande, because it was negatively correlated with p,p'-DDE and Se. Spleen mass was positively correlated with selenium and HSI and negatively correlated with body mass, GSI, Mn, and Ni. Overall, the present study suggests that insectivorous birds living in areas of high agricultural and industrial activity along the Rio Grande bioaccumulate environmental contaminants. These contaminants, particularly p,p'-DDE, may be among multiple factors that impact endocrine and hematopoietic function in Rio Grande swallows.

Heavy metal pollution disturbs immune response in wild ant populations

Concern about the effects of environmental contaminants on immune function in both humans and wildlife is growing and practically nothing is known about this impact on terrestrial invertebrates, even though they are known to easily accumulate pollutants. We studied the effect of industrial heavy metal contamination on immune defense of a free-living wood ant ( Formica aquilonia). To find out whether ants show an adapted immune function in a polluted environment, we compared encapsulation responses between local and translocated colonies. Local colonies showed higher heavy metal levels than the translocated ones but the encapsulation response was similar between the two groups, indicating that the immune system of local ants has not adapted to high contamination level. The encapsulation response was elevated in moderate whereas suppressed in high heavy metal levels suggesting higher risk for infections in heavily polluted areas.

The Effects of Environmental Contaminants in Food on Women’s Health

An essential element of a health-promoting lifestyle is eating nutritious, healthy foods. However, food can be a source of exposure to many types of toxins, and current food production methods can have negative effects on the environment and consumers. This article identifies several of the contaminants present in food and describes adverse health effects from exposure to specific contaminants. Recommendations for how exposure can be prevented or minimized are presented.

Altered hepatic retinol and CYP26 levels in adult European common frogs (Rana temporaria) exposed to p,p′-DDE

The effects of environmental contamination on amphibians are of particular concern because there are reports of declining numbers of species and individuals in most parts of the world during the last 50 years. During the last decade there has been increased focus on the role of persistent organic pollutants as retinoid (vitamin A) disrupters, and their effects on development, growth and sexual differentiation. To study the effects of p,p'-DDE, one of the most persistent metabolites of the pesticide DDT, on retinol homeostasis, we subcutaneously exposed adult male European common frogs (Rana temporaria) to different doses of p,p'-DDE (0, 0.01, 0.1, 1 and 10 mg/kg body mass) and studied the effect of a short term exposure (14 days) on hepatic retinoid levels and CYP26 gene and protein expression. Hepatic retinol concentrations, CYP26 gene and protein levels were analysed using HPLC, quantitative RT-PCR and indirect ELISA, respectively. Our results showed a significant p,p'-DDE dose-specific increase in the hepatic retinol concentration. CYP26 gene and protein expression were reduced in an apparent p,p'-DDE dose-specific manner. The results suggest that p,p'-DDE may interfere with the hepatic metabolism of retinol in adult frogs by decreasing CYP26 expression patterns.