Effects Of Environmental Contaminants Research Articles

Isolation of novel microsatellite loci in Orchesella villosa (Arthropoda, Collembola)

Summary An experimental procedure using biotin-labelled probes and streptavidin-bound magnetic beads (FIASCO) was used to produce a microsatellite-enriched library for the collembolan Orchesella villosa . PCR primers were successfully constructed for seven loci containing, respectively, five pure, one interrupted, and one compound dinucleotide microsatellite repeats. As a preliminary test of their variability, we investigated 15 individuals from 5 locations inside a dismissed mining area in southern Tuscany. All microsatellite loci showed high levels of polymorphism. The mean number of different alleles at each locus across populations was 10.1 and observed heterozygosity per locus was 0.13–0.86. Only 2 out of the 7 loci appeared to be in Hardy–Weinberg equilibrium. The potential application of these loci to test the effects of environmental contamination on the genetic structure of exposed populations is discussed.

DNA adducts, benzo( a)pyrene monooxygenase activity, and lysosomal membrane stability in Mytilus galloprovincialis from different areas in Taranto coastal waters (Italy)

The aim of this study was to investigate the impact of environmental pollution at different stations along the Taranto coastline (Ionian Sea, Puglia, Italy) using several biomarkers of exposure and the effect on mussels, Mytilus galloprovincialis, collected in October 2001 and October 2002. Five sampling sites were compared with a “cleaner” reference site in the Aeronautics Area. In this study we also investigated the differences between adduct levels in gills and digestive gland. This Taranto area is the most significant industrial settlement on the Ionian Sea known to be contaminated by polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, heavy metals, etc. Exposure to PAHs was evaluated by measuring DNA adduct levels and benzo( a)pyrene monooxygenase activity (B( a)PMO); DNA adducts were analyzed by 32P-postlabeling with nuclease P1 enhancement in both gills and digestive glands to evaluate differences between DNA adduct levels in the two tissues. B( a)PMO was assayed in the microsomal fraction of the digestive glands as a result of the high expression of P450-metabolizing enzymes in this tissue. Lysosomal membrane stability, a potential biomarker of anthropogenic stress, was also evaluated in the digestive glands of mussels, by measuring the latent activity of β- N-acetylhexosaminidase. Induction of DNA adducts was evident in both tissues, although the results revealed large tissue differences in DNA adduct formation. In fact, gills showed higher DNA adduct levels than did digestive gland. No significant differences were found in DNA adduct levels over time, with both tissues providing similar results in both years. DNA adduct levels were correlated with B( a)PMO activity in digestive gland in both years ( r=0.60 in 2001; r=0.73 in 2002). Increases were observed in B( a)PMO activity and DNA adduct levels at different stations; no statistical difference was observed in B( a)PMO activity over the two monitoring campaigns. The membrane labilization period in mussels from some stations was decreased in both years. No statistical differences were established in the membrane labilization times from 2001 to 2002. Our results suggest the existence of different sources and amounts of environmental contaminants at the stations investigated. The formation of DNA adducts confirms the existence of activation pathways in mussels and shows the importance of DNA adduct analysis in the gill tissue in addition to the more commonly used digestive gland; these results confirm the utility of lysosomal membrane stability as a biomarker of general stress. Overall, the integrated use of biomarkers of exposure and the effects of environmental contaminants on living marine organisms may help to better interpret the impact of pollutants in a marine coastal environment.

Effects of sham air and cigarette smoke on A549 lung cells: implications for iron-mediated oxidative damage

Inhalation of airborne pollution particles that contain iron can result in a variety of detrimental changes to lung cells and tissues. The lung iron burden can be substantially increased by exposure to cigarette smoke, and cigarette smoke contains iron particulates, as well as several environmental toxins, that could influence intracellular iron status. We are interested in the effects of environmental contaminants on intracellular iron metabolism. We initiated our studies using lung A549 type II epithelial cells as a model, and we evaluated the effects of iron dose and smoke treatment on several parameters of intracellular iron metabolism. We show that iron at a physiological dose stimulates ferritin synthesis without altering the transferrin receptor (TfR) mRNA levels of these cells. This is mediated primarily by a reduction of iron regulatory protein 2. Higher doses of iron reduce iron regulatory protein-1 binding activity and are accompanied by a reduction in TfR mRNA. Thus, for A549 cells, different mechanisms influencing IRP-IRE interaction allow ferritin translation in the presence of TfR mRNA to provide for iron needs and yet prevent excessive iron uptake. More importantly, we report that smoke treatment diminishes ferritin levels and increases TfR mRNA of A549 cells. Ferritin serves as a cytoprotective agent against oxidative stress. These data suggest that exposure of lung cells to low levels of smoke as are present in environmental pollutants could result in reduced cytoprotection by ferritin at a time when iron uptake is sustained, thus enhancing the possibility of lung damage by iron-mediated oxidative stress.

Ecotoxicology of crocodilians

All species of crocodilians are long-lived, top-level carnivores that are integral components of aquatic, wetland, and marine/estuarine ecosystems. However, they are often excluded from studies on environmental contamination and ecological risk assessments. Available organic (including endocrine disrupters), inorganic, and radionuclide contaminant accumulation and effects studies for crocodilians were reviewed and summarized to facilitate the use of existing data, reveal the primary information gaps, promote the inclusion of crocodilians in environmental contamination studies and ecological risk assessments, encourage further ecotoxicological studies, and assist in the development of future research priorities. Environmental contamination studies were not available for more than half of the world's 23 crocodilian species. The majority of information available (almost 70% of reviewed studies) concerning environmental contaminants and their accumulation and effects on crocodilians was for the American alligator ( Alligator mississippiensis ) as a result of the considerable research effort on the effects of endocrine-disrupting contaminants (EDCs) on the alligator population inhabiting Lake Apopka, Florida and the many studies concerning mercury contamination in the southeastern United States, considered to be the most serious environmental threat to that area. With the exception of the extensive research on the effects of EDCs on Lake Apopka's alligators, research on the effects of environmental contaminants on crocodilians is lacking. The review indicated that the effects of EDCs on crocodilians are not confined to Lake Apopka and may occur in crocodilians in many parts of the world, especially in developing tropical areas where organochlorine pesticides are used extensively. For inorganic contaminants, determining the effects of mercury on crocodilians should be the highest research priority.

Effect of environmental contaminants on nasal lysozyme secretions.

Human nasal secretions are comprised of lysozyme and albumin as their main protein components. Lysozyme, an anti-microbial substance, is produced by nasal serous cells while albumin is obtained, primarily, from increased nasal vasculature permeability. We measured lysozyme levels in nasal secretions following challenge by a variety of non-infectious environmental contaminants. The methodology given presents a simple and rapid method of collecting nasal secretions and determining their lysozyme content, a technique which can be used for a host of environmental irritants.

The accumulation and effects of environmental contaminants on snakes: a review.

In any ecological risk assessment, a full complement of the relevant members of the ecosystems being studied should be considered. Reptiles in general, and snakes in particular, are important although often neglected components of terrestrial and aquatic ecosystems and should be included in any study on environmental contamination. By neglecting reptiles, the risks posed by a particular contaminant cannot be fully assessed. Since all snakes are secondary, tertiary, and top predators, they are susceptible to the bioaccumulation of environmental contaminants. Their unique life histories make their roles in food webs diverse and important, and they are crucial to the proper functioning of many ecological processes. We review and summarize organic and inorganic contaminant and radionuclide/radiation residue and lethal and sublethal effects data for snakes to stress the importance of snakes and encourage their inclusion in ecological risk assessments, to demonstrate the paucity of available contaminant data on snakes and reveal the main information gaps, to encourage further ecotoxicological studies on snakes, and to facilitate the use of existing snake contaminant data in ecological risk assessments. This review is the most comprehensive review currently available on the effects on and accumulation of environmental contaminants in snakes.

Doses to Terrestrial Biota in the Vicinity of BNFL Sellafield, Cumbria, UK

Source terms and corresponding radionuclide activity concentrations in biota for 134 Cs, 137 Cs, 238 Pu, 239+240 Pu and 241 Am have been assessed for three semi-natural ecosystems in the vicinity of BNFL Sellafield, Cumbria, UK. Estimates of absorbed doses (mGy.d - 1 ) have been calculated. Doses to key indicator species, Oniscus asellus (detritivorous invertebrate), Carabus violaceous (predatory invertebrate) and Apodemus sylvaticus (granivorous wood mouse) are discussed with reference to the 1 mGy.d -1 level, below which it is postulated that no observable effects on populations in a terrestrial ecosystem occur. Implications for the 'critical group' and reference model' approaches for a framework of radiological environmental protection are discussed. The need to assess the most highly exposed species is advanced. New research focused on the application of biomarker techniques as a mechanism for determining the interactions and effects of environmental contaminants on ecosystem structure and functioning is presented.

Development of a Bioassay to Test the Possible Role of Thiamine Disturbance as a Mechanism Behind Pollution-Induced Reproductive Failures in Birds

A test system was developed to examine the effects of environmental contaminants on thiamine homeostasis in bird embryos. This system employs fresh chicken egg yolk lipids as a vehicle for use in egg injection studies. Furazolidone, an antibiotic suspected to interfere with thiamine metabolism, was used as a positive control to evaluate the utility of the test system. It was determined that fresh chicken egg yolk lipids were preferable over chemical vehicles as it resulted in lower mortality rates (16% versus 23-62%) and did not induce any observable effects in the embryo. Injection of 1 mg/egg of furazolidone at day 0 of development resulted in decreased respiration followed by death, with mortality rates being twice as high as in carrier controls. In addition, transketolase activity, which was measured as an indicator of thiamine availability in the body, was decreased 25% in brains of 19-day-old embryos. This mechanism may be of importance for effects of environmental contaminants in wild bird populations.

Use of Synthetic Human Luteinizing Hormone Releasing Hormone for Induction of Breeding in the Cricket Frog, Acris crepitans

ABSTRACT In order to study the effects of environmental contaminants on the sexual development of the cricket frog, Acris crepitans, a system of laboratory breeding of this species was devised using induction of mating by subcutaneous injection of synthetic human luteinizing hormone releasing hormone at doses ranging from 169–676 mg/kg body weight. Viable tadpoles were obtained from frogs that had been maintained in captivity for approximately 1.5 years and from recently captured individuals. The techniques and doses described represent a starting point for further studies aimed at optimizing captive breeding technique for this species

The Political Economy of Oil, Autos, and the Urban Environment in Venezuela

When Venezuela's economy, dependent on oil exports by the state-owned transnational corporation, produces a large surplus which the government uses to invest in urban infrastructure, especially highways. Highway investments and low gasoline prices reinforce auto dependency and contribute to urban congestion, air pollution, and public health problems. Oil and auto dependency benefit the middle and upper strata of the population, which have the highest levels of car ownership. The majority of the urban population do not own vehicles and suffer the worst consequences of environmental contamination.

Genetics of radionuclide‐contaminated mosquitofish populations and homology betweenGambusia affinisandG. holbrooki

AbstractThe effects of radionuclide contamination on genetic structure of eastern mosquitofish (Gambusia holbrooki) populations from the U.S. Department of Energy's Savannah River Site (SRS) were investigated to develop methods of assessing ecological risk of chronic exposures to xenobiotics. Fish from two contaminated and two reference sites were examined by the randomly amplified polymorphic DNA (RAPD) technique, which revealed that the frequency of three markers was greater in the contaminated than the reference sites and that the frequency of two markers was greater in the reference than in the contaminated sites. A previous study examined populations of western mosquitofish (G. affinis) from the Oak Ridge National Laboratory (ORNL) and found that certain RAPD markers were present in radionuclide‐contaminated ORNL populations at a higher frequency than in reference populations. The “contaminant‐indicative” markers observed in the SRS populations were the same size and amplified by the same polymerase chain reaction primers used in the ORNL study. Southern blot analysis revealed that the SRSG. holbrookicontaminant‐indicative markers were homologous to the ORNLG. affiniscontaminant‐indicative markers. The observation that two species show similar patterns of band frequency shifts at two separate localities is consistent with the hypothesis that these DNA markers may originate from genetic elements that provide a selective advantage in contaminated habitats. Thus, the methodology used in these studies may prove to be useful to indicate population‐level effects of environmental contamination.

Child health, poverty and the environment: the Canadian context.

In Canada, there has been little research exploring the link between child poverty and exposure to environmental contaminants. However, children living in poverty are more likely to grow up in neighbourhoods adjacent to polluting industries and heavily used transportation corridors. They are also more likely to live in improperly designed or maintained buildings where levels of contaminants and toxic residuals may be high, and indoor air quality poor. Risk factors such as exposure to cigarette smoke and poor nutritional status, together with the above living conditions during growth and development, create conditions that make children living in poverty more vulnerable to the effects of environmental contaminants. In Toronto, the South Riverdale Community Health Centre is developing grassroots techniques to build awareness and protect citizens. Given the growing levels of child poverty in Canada and decreasing environmental protection, the author suggests increased community action and health research for use in advocating for appropriate policy changes.

Forms and Prevalence of Intersexuality and Effects of Environmental Contaminants on Sexuality in Cricket Frogs (Acris crepitans)

Forms and Prevalence of Intersexuality and Effects of Environmental Contaminants on Sexuality in Cricket Frogs (Acris crepitans)

Relationship between deer mouse population parameters and dieldrin contamination in the Rocky Mountain Arsenal National Wildlife Refuge

A small-mammal capture-recapture study was conducted in the Rocky Mountain Arsenal National Wildlife Refuge to quantify the effects of soil contamination with dieldrin on demographic parameters of deer mouse (Peromyscus maniculatus) populations. Increased dieldrin concentrations were significantly associated with larger deer mouse populations, although the size of populations on contaminated sites decreased during the study. The most parsimonious model for estimating survival rates was one in which survival was a decreasing function of dieldrin concentration. A significantly higher proportion of female deer mice in the populations residing on the more highly contaminated sites exhibited signs of reproductive activity. Development of genetic resistance in P. maniculatus to chronic chemical exposure is suggested as a possible mechanism responsible for the species' observed dominance and relatively high densities on contaminated sites. Under the additional stress of unfavorable environmental conditions, however, these populations may suffer disproportionately greater mortality. The design and analytical methods presented offer a rigorous statistical approach to assessing the effects of environmental contamination on small mammals at the population level.

A database for environmental contaminants in traditional foods in northern and arctic Canada: Development and applications

The potential health effects of environmental contaminants in traditional food has become a concern among northern communities because of the presence of environmental contaminants in the Arctic ecosystem. Exposure assessments are needed but they require comprehensive dietary information and contaminant data. Over the last 10 years, there has been considerable effort to monitor the level of contaminants in fish and wildlife collected from different regions in northern and Arctic Canada. The development of a database and its application for dietary contaminant exposure assessment are described. We conducted an extensive literature review on levels of environmental contaminants in northern and Arctic Canada. The ranges of levels of four contaminants of major concern (chlordane, mercury, polychlorinated biphenyls and toxaphene) in 81 species of marine mammals, terrestrial mammals, birds, fish and plants are summarized. These data represent 69% of the 117 species of fish, wildlife and plants mentioned in our dietary interviews conducted in the northern communities. A significant percentage of the foods had contaminant levels exceeding the guidelines used by Health Canada for market food consumed by the ‘southern’ populations. Mathematic modelling of the distributions of the data showed that contaminant levels in most food groups are log‐normally distributed and have a typical coefficient of variation of about 100%. Examples are presented to demonstrate the use of the data for contaminant exposure assessment. Average contaminant exposure levels estimated using the database for two communities are comparable to those obtained previously using community specific data. With the current knowledge of environmental contaminant levels in the northern traditional food system, it may be feasible to conduct preliminary risk assessment of dietary exposure of environmental contaminants when some diet information for a community is available. Further sampling and analysis may be needed only for confirmation purposes.

Potential Effects of Environmental Contaminants on Recovery of the Aplomado Falcon in South Texas

Efforts to reintroduce the aplomado falcon (Falco femoralis) into its former range in the southern part of Texas began in 1977. Not until 1993, however, were a significant number (26) of fledgling aplomado falcons released. The first nesting pair of aplomado falcons was reported near the Brownsville Ship Channel during 1995. Because of a long history of pesticide use in the Lower Rio Grande Valley, during 1993-94 we investigated the accumulation of environmental contaminants in plasma of aplomado falcons released at the Laguna Atascosa National Wildlife Refuge. We also assessed the potential contribution of typical prey species to aplomado falcon contaminant burdens. Organochlorine pesticides and PCBs were below detection limits (wet wt basis) in plasma; however, some organochlorines including 1.75 and 1.41 μg/g p,p'-DDE, and 0.49 and 1.52 μg/g total PCBs were detected in addled eggs collected in 1995 and 1996. Mercury also was detected at 1.5 and 4.1 μg/g dry weight in the addled eggs collected in 1995 and 1996. We detected DDE (range 0.02-0.25 μg/g) in carcasses of potential prey of the aplomado falcon. Trace metals also were detected in potential prey at levels which are not of concern, except for Hg, which was high in a few meadowlarks. Low levels of DDE and most trace metals in potential prey, including mourning doves (Zenaida macroura) and eastern meadowlarks (Sturnella magna), are not likely to result in adverse effects on the aplomado falcon in the Lower Rio Grande Valley. However, elevated Hg residues in meadowlarks (in a few cases) and potentially higher DDE levels in other prey species such as the great-tailed grackle (Quiscalus mexicanus) could result in negative effects on reproduction and survival of some aplomado falcons in south Texas.

Current technology in newborn universal hearing detection: Jacobson J.; Jacobson C.A.Semin. Hear. (USA) (1996) 17/2 (125–138)

Thyroid hormones (TH) are critical for growth and development and particularly brain development. There are numerous environmental agents that lead to marginal reductions of circulating TH. Although it is clear that severe developmental hypothyroidism is profoundly detrimental to neurodevelopment, there is less information regarding the consequences of modest degrees of thyroid. The impact of low level TH disruptions induced by environmental contaminants has not been defined. This paper is a synopsis from four invited speakers who presented at the 13th International Neurotoxicology Association meeting held in Xi’an, China during the summer of 2011. An overview of the role of TH in brain development and a review of human and animal data on the neurological sequelae of disruption of the thyroid axis in the pre- and early post-natal periods were presented by Mary Gilbert and Joanne Rovet. Iodine deficiency, a common cause of TH insufficiency and mental retardation in many countries, including China, was addressed by Zupei Chen. In this presentation the current incidence of iodine deficiency and neurological outcome in China and the efficacy of recently implemented iodinization programs to eliminate this cause of mental retardation were reviewed. Joanne Rovet described the impact of TH disruption during pregnancy and under conditions of congenital hypothyroidism. Children born with normal thyroid function, but who experienced TH insufficiency in the womb, display subtle cognitive impairments and abnormalities in brain imaging. Despite early detection and treatment, deficiencies also exist in children born with thyroid disorders. Different patterns of cognitive effects result from prenatal versus postnatal TH insufficiency. Mary Gilbert reported on the effects of environmental contaminants with thyroid disrupting action on brain development in animals. Results of neurophysiological, behavioral, structural and molecular alterations that accompany modest perturbations of the thyroid axis were reviewed. Noriyuki Koibuchi described molecular targets of TH-mediated signalling accompanying exposure to persistent organic pollutants. Both polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are prevalent environmental contaminants that disrupt TH signalling at the receptor level. This action by these chemical classes could contribute to the negative impact of these chemicals on brain function. In summary, epidemiological, preclinical and animal research has clearly identified the critical role of TH in brain development. Additional work is required to understand the impact of low level perturbations of the thyroid axis to evaluate the risk associated with environmental contaminants with thyroid action.

Effects of environmental contaminants in wildlife species

Effects of environmental contaminants in wildlife species

Environmental contaminants influencing immunefunction in marine bivalve molluscs

The increased observation of pollution induced disease conditions in marine organisms has led to a growing interest on the effects of environmental contaminants on the immune system. Most studies on modulation of the immune system in bivalves by pollutants have concentrated on the effects of heavy metals and polycyclic aromatic hydrocarbons (PAHs). The current literature on contaminant effects on specific components of the bivalve immune system is reviewed together with the effects on susceptibility to infection. Data are presented showing the effects on immune parameters of exposure to Vibrio tubiashi following pre-exposure to copper or cadmium. Mussels exposed to cadmium for 7 days followed by 7 days exposure to V. tubiashi demonstrated significantly higher numbers of circulating haemocytes compared with non- Vibrio-exposed groups. Similar experiments conducted with copper exposure for both 7 days and 7 weeks followed by V. tubiashi for 7 days demonstrated a significant decrease in the percentage of circulating eosinophils compared with basophilic cells for both short and long term exposures. The intracellular release of superoxide (NBT reduction) by haemocytes was stimulated in Vibrio-challenged mussels with no copper pre-exposure but was significantly reduced in mussels pre-exposed to 0·2 ppm of copper for 7 weeks. The mortalities for the copper experiments showed increased levels with increasing copper concentration and were consistently higher in the V. tubiashi challenged mussels which had also been exposed to copper.

The forgotten casualties: women, children, and environmental change

The concept of equity is used to highlight the impacts of environmental change on women and children. Three types of equity are defined (social, generational, and procedural) and both process and outcome (distributions) dimensions are described. The application of the equity concept to the understanding of the socio-spatial impacts on women and children is illustrated using three themes. The effect of environmental contamination on women and children provides an example of generational inequity. Evidence of social inequity is seen in the poverty, population, environmental degradation spiral especially as it compromises the wellbeing of women and children and their ability to mitigate the consequence of environmental disturbances. Finally, procedural inequities are described in the context of equal rights for women, including their rights to resources. Women and children bear and will continue to bear a disproportionate burden of global environmental changes. They also have unequal capabilities and opportunities for adjustments, rendering them more vulnerable to the regional and global environmental transformations currently underway.