Skip to content. Skip to navigation
Sections
Personal tools
You are here: Home
Featured Journal
Navigation
Site Search
 
Search only the current folder (and sub-folders)
Log in


Forgot your password?
New user?
Check out our New Publishers' Select for Free Articles
Journal Search

Archives of Environmental Contamination and Toxicology (v.64, #2)


Source Identification of Soil Mercury in the Spanish Islands by José Antonio Rodríguez Martín; Gregoria Carbonell; Nikos Nanos; Carmen Gutiérrez (pp. 171-179).
This study spatially analysed the relation between mercury (Hg) content in soil and Hg in rock fragment for the purpose of assessing natural soil Hg contribution compared with Hg from human inputs. We present the Hg content of 318 soil and rock fragment samples from 11 islands distributed into two Spanish archipelagos (the volcanic Canary Islands [Canaries] and the Mediterranean Balearic [Balearic] islands). Assumedly both are located far enough away from continental Hg sources to be able to minimise the effects of diffuse pollution. Physical and chemical soil properties were also specified for the samples. Hg contents were significantly greater in the Balearic limestone soils (61 μg kg−1) than in the volcanic soils of the Canaries (33 μg kg−1). Hg levels were also greater in topsoil than in rocky fragments, especially on the Balearics. The soil-to-rock ratios varied between 1 and 30. Interestingly, the highest topsoil-to-rock Hg ratio (>16 ×) was found in the vicinity of a coal-fired power plant in Majorca, whereas no similar areas in the Canary archipelago were identified.

Decomposition of Polychlorinated Biphenyls in Soil With a Dispersion Mixture of Metallic Calcium and Calcium Oxide by Yoshiharu Mitoma; Srinivasa Reddy Mallampati; Hideaki Miyata; Mitsunori Kakeda (pp. 180-186).
This study describes the decomposition of polychlorinated biphenyls (PCBs) in soil with dispersion mixtures of metallic calcium (Ca) and calcium oxide (CaO) at different temperatures. In these experiments, naturally moisturized and contaminated soil (1.0 g [31 ppm PCBs]), CaO (dried 2.0 wt%), and metallic Ca (0.01 g [0.25 mmol]) were introduced into a stainless steel pressure reactor under 0.1 MPa N2 gas. The mixtures were stirred magnetically and heated at 260, 280, and 300 °C, respectively. Soil treatment with metallic Ca and CaO under various temperature conditions is extremely effective for degrading existing PCBs. Decomposition resulted from dechlorination (DC). Initial moisture in soil acted as a hydrogen source during stirring. Soil moisture can be beneficial for hydrodechlorination in the presence of metallic Ca and CaO. Furthermore, metallic Ca and CaO can greatly increase the number of collisions and mutual refinement. Treatment at 260, 280, and 300 °C combined with metallic Ca and CaO is effective for the decomposition (approximately 95 % DC) of PCBs in soil under natural moisture conditions.

Biodegradability, Cytotoxicity, and Physicochemical Treatability of Two Novel Perfluorooctane Sulfonate-Free Photoacid Generators by Wenjie Sun; Victor M. Gamez; Lila Otero-Gonzalez; Youngjin Cho; Christopher K. Ober; Reyes Sierra-Alvarez (pp. 187-197).
There is a need for effective, environmentally compatible photoacid generators (PAGs) for application in photolithography for microelectronic device fabrication. Perfluoroalkyl sulfonates (PFAS) used in conventional PAG formulations, such as perfluorooctane sulfonate (PFOS), are under increasing scrutiny due to their widespread environmental distribution and toxicity. Recently, two new PFAS-free, PAG anions with semifluorinated sulfonate anions containing biomolecules (γ-butyrolactone or d-glucose groups) were successfully applied as PAGs. In this study, the biodegradation potential, cytotoxicity, and physicochemical treatability of the new PAG anions was evaluated. PFOS and perfluorobutane sulfonate (PFBS) were used as reference materials in all of the assays. The new PAGs were susceptible to partial degradation by microorganisms in aerobic activated sludge, and these were also readily removed by chemical oxidative treatment with Fenton’s reagent [H2O2/Fe(II)]. In contrast, the compounds were resistant to microbial and chemical attack under reductive conditions as indicated by the low removal efficiencies observed with anaerobic biodegradation assays and chemical assays with zero-valent iron, respectively. The enhanced biodegradation potential and treatability make of the new PAGs attractive materials to resolve current issues related to the lithographic performance and environmental concerns.

Polyfluorinated and Perfluorinated Chemicals in Precipitation and Runoff from Cities Across Eastern and Central China by Lijie Zhao; Meng Zhou; Tao Zhang; Hongwen Sun (pp. 198-207).
Twenty-three polychlorinated and perfluorinated compounds (PFCs) were investigated in water phase and particulate matters of 19 precipitation samples (18 snow samples and 1 rain sample) from different cities across eastern and central China collected in February 2010. The PFCs in samples of 9e precipitation events during more than half a year at 1 site in Tianjin and 6 successive samples during 1 precipitation event were measured to elucidate the change of PFC in precipitation. In addition, PFCs in 3 runoffs at different kinds of sites in Tianjin were compared with those in the corresponding precipitation. The results showed that the particulate matters separated from the precipitation contained undetectable PFCs. The total PFC concentration ranged between 4.7 and 152 ng L−1 in water phase of the precipitation samples, with perfluorooctanoic acid (PFOA) being detected at all of the sampling sites and the dominant PFC at most of the sampling sites. Some potential precursors of environmentally concerned PFCs and their degradation intermediates were measured simultaneously, among which 6:2 fluorotelomer unsaturated carboxylic acid (6:2 FTUCA), 8:2 FTUCA, and  × (3, 4, 5, 7):3 acid [F(CF2)xCH2CH2COOH] were measured for the first time in Chinese precipitations; however, their concentrations were all lower than the limits of detection except that 6:2 FTUCA and 8:2 FTUCA could be detected in 3 and 8 precipitation samples, respectively. No clear seasonal variation in PFC concentrations in precipitation was observed during half a year; however, a relatively greater average concentration of total PFCs was observed during winter and summer compared with spring. The concentration of individual PFCs showed an obvious descending trend in the successive samples of the precipitation event. PFOA and perfluorononanoic acid in runoffs collected from different sites showed the following similar pattern—gas station > highway > university campus—whereas the other detected PFCs had no concurrent trend.

Influences of Sampling Methodologies on Pesticide-Residue Detection in Stream Water by Zisheng Xing; Lien Chow; Herb Rees; Fanrui Meng; Sheng Li; Bill Ernst; Glenn Benoy; Tianshan Zha; L. Mark Hewitt (pp. 208-218).
Traditional grab sampling (GS) used widely in the study of water quality has been found lacking in spatial and temporal resolution for pesticide residue monitoring in stream water. The objectives of this article are to present a hydrograph-based sampling approach and compare it with traditional GS according to sensitivity at temporal and spatial scales and maximum concentrations of pesticide residues detected in-stream. Data collected from streams receiving water from three nested watersheds located in northwestern New Brunswick, Canada, were used in this study. The results showed that the hydrograph-based sampling method detected 20 to 30 % more pesticide cases than GS for rainfall events causing runoff. Grab sampling significantly underestimated average concentrations of pesticide residues by 50 % and maximum concentrations by 1 to 3 orders of magnitude. Using a modified sampler design, the spatial and temporal variability of pesticide residues was more accurately captured by hydrograph-based sampling, and therefore its use in monitoring programs is recommended.

Impacts of Manganese Mining Activity on the Environment: Interactions Among Soil, Plants, and Arbuscular Mycorrhiza by Facundo Rivera-Becerril; Lucía V. Juárez-Vázquez; Saúl C. Hernández-Cervantes; Otilio A. Acevedo-Sandoval; Gilberto Vela-Correa; Enrique Cruz-Chávez; Iván P. Moreno-Espíndola; Alfonso Esquivel-Herrera; Fernando de León-González (pp. 219-227).
The mining district of Molango in the Hidalgo State, Mexico, possesses one of the largest deposits of manganese (Mn) ore in the world. This research assessed the impacts of Mn mining activity on the environment, particularly the interactions among soil, plants, and arbuscular mycorrhiza (AM) at a location under the influence of an open Mn mine. Soils and plants from three sites (soil under maize, soil under native vegetation, and mine wastes with some vegetation) were analyzed. Available Mn in both soil types and mine wastes did not reach toxic levels. Samples of the two soil types were similar regarding physical, chemical, and biological properties; mine wastes were characterized by poor physical structure, nutrient deficiencies, and a decreased number of arbuscular mycorrhizal fungi (AMF) spores. Tissues of six plant species accumulated Mn at normal levels. AM was absent in the five plant species (Ambrosia psilostachya, Chenopodium ambrosoides, Cynodon dactylon, Polygonum hydropiperoides, and Wigandia urens) established in mine wastes, which was consistent with the significantly lower number of AMF spores compared with both soil types. A. psilostachya (native vegetation) and Zea mays showed mycorrhizal colonization in their root systems; in the former, AM significantly decreased Mn uptake. The following was concluded: (1) soils, mine wastes, and plant tissues did not accumulate Mn at toxic levels; (2) despite its poor physical structure and nutrient deficiencies, the mine waste site was colonized by at least five plant species; (3) plants growing in both soil types interacted with AMF; and (4) mycorrhizal colonization of A. psilostachya influenced low uptake of Mn by plant tissues.

Influence of Exposure Concentration and Duration on Effects and Recovery of Lemna minor Exposed to the Herbicide Norflurazon by P. Chris Wilson; Ruben Koch (pp. 228-234).
This study evaluated the effects and potential recovery of the surrogate aquatic macrophyte Lemna minor exposed to the herbicide norflurazon for 10 days under controlled conditions. Decreases in frond production occurred as early as 2 days after treatment (DAT) at concentrations ≥250 μg/L. The observed no observable-adverse effects and lowest observable-adverse effects concentrations during the 2-, 6-, and 10-day exposure periods were 100/250, 10/25, and 10/25 μg/L, respectively, for total frond production. The estimated EC50 value for total frond production was 24.9 ± 4.1 μg/L (6 days of exposure). Symptoms of norflurazon toxicity (bleaching of foliage) were apparent within 2 DAT for concentrations ≥25 μg/L with 30–39 % of the fronds within each treatment exhibiting symptoms of toxicity. After 6- and 10-day exposures, 69–77 and 80–95 % of these plants showed toxic symptoms, respectively. Symptoms of toxicity for the 10 μg/L treatment first appeared at 4 DAT (51 % of fronds were symptomatic), peaked at 91 % 8 DAT, and were only 2 % at 10 DAT, thus indicating recovery. Norflurazon toxicity was eventually reversible at all concentrations once it was removed from the nutrient solutions. After 17 days of recovery (27 DAT), growth rates for all concentrations ≤250 μg/L were similar to those of the controls. Growth rates for all treatment concentrations recovered to control levels after 28 days of recovery (38 DAT).

Arsenite Tolerance is Related to Proportional Thiolic Metabolite Synthesis in Rice (Oryza sativa L.) by Richa Dave; Pradyumna Kumar Singh; Preeti Tripathi; Manju Shri; Garima Dixit; Sanjay Dwivedi; Debasis Chakrabarty; Prabodh Kumar Trivedi; Yogesh Kumar Sharma; Om Prakash Dhankher; Francisco Javier Corpas; Juan B. Barroso; Rudra Deo Tripathi (pp. 235-242).
Thiol metabolism is the primary detoxification strategy by which rice plants tolerate arsenic (As) stress. In light of this, it is important to understand the importance of harmonised thiol metabolism with As accumulation and tolerance in rice plant. For this aim, tolerant (T) and sensitive (S) genotypes were screened from 303 rice (Oryza sativa) genotypes on exposure to 10 and 25 μM arsenite (AsIII) in hydroponic culture. On further As accumulation estimation, contrasting (13-fold difference) T (IC-340072) and S (IC-115730) genotypes were selected. This difference was further evaluated using biochemical and molecular approaches to understand involvement of thiolic metabolism vis-a-vis As accumulation in these two genotypes. Various phytochelatin (PC) species (PC2, PC3 and PC4) were detected in both the genotypes with a dominance of PC3. However, PC concentrations were greater in the S genotype, and it was noticed that the total PC (PC2 + PC3 + PC4)–to–AsIII molar ratio (PC-SH:AsIII) was greater in T (2.35 and 1.36 in shoots and roots, respectively) than in the S genotype (0.90 and 0.15 in shoots and roots, respectively). Expression analysis of several metal(loid) stress–related genes showed significant upregulation of glutaredoxin, sulphate transporter, and ascorbate peroxidase in the S genotype. Furthermore, enzyme activity of phytochelatin synthase and cysteine synthase was greater on As accumulation in the S compared with the T genotype. It was concluded that the T genotype synthesizes adequate thiols to detoxify metalloid load, whereas the S genotype synthesizes greater but inadequate levels of thiols to tolerate an exceedingly greater load of metalloids, as evidenced by thiol-to-metalloid molar ratios, and therefore shows a phytotoxicity response.

Contribution of Cell Walls, Nonprotein Thiols, and Organic Acids to Cadmium Resistance in Two Cabbage Varieties by Jianyun Sun; Jin Cui; Chunling Luo; Lu Gao; Yahua Chen; Zhenguo Shen (pp. 243-252).
To study possible cadmium (Cd) resistance mechanisms in cabbage (Brassica oleracea L.), several parameters of metal uptake, distribution, and complexation were compared between two varieties Chunfeng [CF (Cd-tolerant)] and Lvfeng [LF (Cd-sensitive)]. Results showed that CF contained significantly lower Cd concentrations in leaves and higher Cd concentrations in roots than LF. Approximately 70 to 74 % and 66 to 68 % of Cd taken up by LF and CF, respectively, was transported to shoots. More Cd was bound to the cell walls of leaves, stems, and roots in CF than in LF. The higher capacity of CF to limit Cd uptake into shoots could be explained by immobilization of Cd in root cell walls. Compared with control groups, Cd treatment also significantly increased concentrations of nonprotein thiols, phytochelatins (PCs), and citric acid in the leaves and roots of the two varieties; the increases were more pronounced in CF than in LF. Taken together, the results suggest that the greater Cd resistance in CF than in LF may be attributable to the greater capacity of CF to limit Cd uptake into shoots and complex Cd in cell walls and metal binding ligands, such as PCs and citric acid. However, the contributions of PCs and citric acid to Cd detoxification might be smaller than those in cell walls.

Endosulfan Effects on Rana dalmatina Tadpoles: Quantitative Developmental and Behavioural Analysis by Manuela Lavorato; Ilaria Bernabò; Antonio Crescente; Mathieu Denoël; Sandro Tripepi; Elvira Brunelli (pp. 253-262).
Endosulfan is an organochlorine pesticide that was recently labeled as a persistent organic pollutant, but it is still widely employed, particularly in developing countries. The goal of this study is to evaluate the acute (LC50) and chronic effects (developmental and behavioural traits) of this insecticide on Rana dalmatina tadpoles after exposure to ecologically relevant concentrations (0.005, 0.01, and 0.05 mg/L) by applying video-tracking techniques to evaluate the quantitative effect of endosulfan on amphibian behavioural patterns. The 96 h LC50 value was 0.074 mg endosulfan/L. Tadpoles chronically exposed to 0.01 and 0.05 mg endosulfan/L underwent high mortality rate, decreased larval growth, delayed development, and increased incidence of malformations, and they did not reach metamorphosis by the end of the experiment. Moreover, tadpoles exposed to these concentrations exhibited several abnormalities in swimming patterns, such as shorter distance moved, swirling, resting, and unusual use of space. The exposure to 0.005 mg endosulfan/L did not cause any significant effects on behaviour, larval growth, or development, but we observed a significant decrease in both survival and time to metamorphosis. We showed that developmental abnormalities are dose-dependent and that the pesticide effects could differ depending on the endosulfan concentration and the species tested. We also validated the hypothesis that behavioural analysis, along with the use of new analytical methods, could be a useful tool in amphibian ecotoxicological studies.

Humic Substances Increase Survival of Freshwater Shrimp Caridina sp. D to Acid Mine Drainage by Aleicia Holland; Leo J. Duivenvoorden; Susan H. W. Kinnear (pp. 263-272).
Humic substances (HS) are known to decrease the toxicity of heavy metals to aquatic organisms, and it has been suggested that they can provide buffering protection in low pH conditions. Despite this, little is known about the ability for HS to increase survival to acid mine drainage (AMD). In this study, the ability of HS to increase survival of the freshwater shrimp (Caridina sp. D sensu Page et al. in Biol Lett 1:139–142, 2005) to acid mine drainage was investigated using test waters collected from the Mount Morgan open pit in Central Queensland with the addition of Aldrich humic acid (AHA). The AMD water from the Mount Morgan open pit is highly acidic (pH 2.67) as well as contaminated with heavy metals (1780 mg/L aluminum, 101 mg/L copper [Cu], 173 mg/L manganese, 51.8 mg/L zinc [Zn], and 51.8 mg/L iron). Freshwater shrimp were exposed to dilutions in the range of 0.5 % to 5 % AMD water with and without the addition of 10 or 20 mg/L AHA. In the absence of HS, all shrimp died in the 2.5 % AMD treatment. In contrast, addition of HS increased survival in the 2.5 % AMD treatment by ≤66 % as well as significantly decreased the concentration of dissolved Cu, cobalt, cadmium, and Zn. The decreased toxicity of AMD in the presence of HS is likely to be due to complexation and precipitation of heavy metals with the HS; it is also possible that HS caused changes to the physiological condition of the shrimp, thus increasing their survival. These results are valuable in contributing to an improved understanding of potential role of HS in ameliorating the toxicity of AMD environments.

Pre-Exposure to Heavy Metal Pollution and the Odor of Predation Decrease the Ability of Snails to Avoid Stressors by Hugh Lefcort; Elizabeth A. Wehner; Paul L. Cocco (pp. 273-280).
Many organisms appear to exhibit adaptive cost–benefit behaviors that balance foraging, safety, and pollution avoidance. However, what if the cognitive facilities needed to make decisions are compromised by industrial pollutants? Are the resulting decisions altered? Similarly, does exposure to kairomones from predators alter an organism’s ability to avoid toxicants? Furthermore, how long an exposure is necessary: A few minutes, hours, or even a lifetime? We wondered if there was an interaction between the ability to respond to a predatory event and the ability to avoid heavy metals.

Reproductive Impairment of a Viviparous Fish Species Inhabiting a Freshwater System with Anthropogenic Impact by Andrea Cecilia Hued; Fabiana Laura Lo Nostro; Daniel Alberto Wunderlin; María de los Ángeles Bistoni (pp. 281-290).
The potential threat to animal reproduction by contaminated freshwater systems posed the necessity to identify and develop bioindicators and biomarkers to be used for screening and evaluation of the effects in organisms. The main goal of this work was to determine, through histological analyses and changes in gonopodium morphology, whether a freshwater system polluted by anthropogenic activities—sewage, agricultural, and industrial—could cause alterations at the organ level. We also propose the live-bearing fish, Jenynsia multidentata, as a species suitable to study the effects of contaminated aquatic environments. We compared male fish sampled at two different stations in Suquía River basin (Córdoba, Argentina), both differing in degree of pollution, through liver and testis histology and gonopodial morphometric parameters. The water quality, based on the physicochemical characteristics of the studied stations, varied markedly with a decrease in water quality at the downstream site (station 2). At the highest polluted area, detrimental effects on liver and testis were evidenced on histological analysis. Male individuals from station 2 also presented noticeable structural changes of the anal fin, such as a straight gonopodium and abnormal tip area. The present results demonstrate that a freshwater system polluted by the impacts of anthropogenic activities has detrimental effects to J. multidentata. The alterations registered in individuals from the polluted station indicate an impairment of male reproductive performance and imply a risk for other live-bearing species as well as the entire biodiversity. We consider J. multidentata a sentinel species that is useful to evaluate the potential risk present in the studied basin not only to itself but to other species as well.

The Effects of Salinity and Salinity+Metal (Chromium and Lead) Exposure on ATPase Activity in the Gill and Intestine of Tilapia Oreochromis niloticus by Emine Baysoy; Gülüzar Atli; Mustafa Canli (pp. 291-300).
Freshwater organisms are highly sensitive to increases in salinity because they causes serious osmoregulation problems. Salinity of inland waters can be increased as a result of anthropogenic activities. In this study, freshwater fish Oreochromis niloticus were exposed individually to increased salinities (0, 2, and 8 ppt) alone and salinity+metal [1 μg/mL chromium (Cr) or lead (Pb) exposure at 2 and 8 ppt] exposures for different time periods (1, 7, and 14 days) to investigate the response of Na+/K+-ATPase and Mg2+-ATPase in the osmoregulatory tissues (gill and intestine). Results showed that enzyme activity varied depending on salinity, tissue, metal, and exposure duration. Metal levels in controls and salinity-exposed groups were lower than the detection limit, although significant Cr and Pb accumulation occurred in the salinity+metal combination groups. In salinity-exposed groups, there were increasing trends in the enzyme activity, whereas there were decreasing trends in the metal+salinity groups. Gill ATPases were more affected by the exposure conditions compared with intestine ATPases. Results showed that salinity+metal exposure both played significant roles on ATPase activities in the osmoregulatory tissues, although the alterations in the activity were mostly insignificant supporting compensation mechanisms. Results also suggest that the osmoregulation of freshwater fish should be investigated in toxicity- monitoring programs in inland waters.

Effects of Waterborne Chronic Copper Exposure on Hepatic Lipid Metabolism and Metal-Element Composition in Synechogobius hasta by Qi-Liang Chen; Zhi Luo; Xu Liu; Yu-Feng Song; Cai-Xia Liu; Jia-Lang Zheng; Yan-Hong Zhao (pp. 301-315).
The present study was conducted to determine hepatic lipid metabolism and metal-element composition in Synechogobius hasta exposed to waterborne chronic copper (Cu) concentrations of control, 57, and 118 μg Cu/l, respectively, for 30 days. Growth decreased, but hepatosomatic index, viscerosomatic index, and hepatic lipid content increased with increasing waterborne Cu levels. Staining with oil red O showed extensive steatosis in liver of Cu-exposed fish. Cu exposure increased hepatic 6-phosphogluconate dehydrogenase, glucose-6-phosphate dehydrogenase, and malic enzyme activities, whereas fatty acid synthetase, isocitrate dehydrogenase, and carnitine palmitoyltransferases I activities remained unaffected. Cu, zinc, iron, and manganese contents were also changed in several tissues (gill, liver, spleen, gastrointestinal tract, and muscle) in a tissue-, dose-, and time-dependent manner. This was the first study to examine the effects of waterborne Cu exposure on several enzymatic activities mediating hepatic lipogenesis and lipolysis in fish as well as to show that waterborne Cu exposure could enhance the metabolism of lipid synthesis and consequently induce the increase of hepatic lipid deposition in S. hasta.

The Effects of Short-Term Exposure to an Endocrine Disrupter on Behavioral Consistency in Male Juvenile and Adult Siamese Fighting Fish by Teresa L. Dzieweczynski; Olivia L. Hebert (pp. 316-326).
17α-Ethinyloestradiol (EE2) is known to impact courtship and aggression but how exposure affects the consistency with which individuals express these behaviors over time is not commonly addressed. In addition, how juvenile and adult male fish differ in levels of behavioral consistency, both before and after EE2 exposure, is unknown. To examine these questions, juvenile and adult male Siamese fighting fish were presented with a dummy male and dummy female simultaneously both before and after acute exposure to a nominal (15 ng/L) dose of EE2. Multiple trials were conducted to measure how consistent individual differences are affected by age and EE2 exposure. Both female- and male-directed behaviors decreased after short-term exposure to EE2. Juvenile and adult fish differed in the number of female-directed tail beats and bites they performed, with adult fish performing more tail beats and juvenile fish performing more bites. EE2 exposure had a greater effect on consistent individual differences in female-directed than in male-directed behaviors, which may be a byproduct of intense artificial selection for aggression in this species. Repeatability values were lower both before and after exposure in juvenile than in adult fish, suggesting that individuals become more consistent with age. This study suggests that male Siamese fighting fish vary in their sensitivity to short-term EE2 exposure and stresses the importance of examining behavior over multiple time points both within and across age classes to gain a more thorough understanding of the effects of endocrine disruptors on behavior.

Decreased Immune Response in Zebra Finches Exposed to Sublethal Doses of Mercury by Catherine A. Lewis; Daniel A. Cristol; John P. Swaddle; Claire W. Varian-Ramos; Patty Zwollo (pp. 327-336).
Mercury (Hg) is a ubiquitous contaminant with deleterious effects on many wildlife species. Most studies to date have focused on fish-eating birds and mammals because much historical Hg pollution is aquatic. Recently, however, comparable blood-Hg levels have been found in terrestrial insectivorous songbirds. As a result, research is needed to clarify the effects of Hg exposure on songbirds. One fundamental end point that is still poorly understood is the effect of Hg on the songbird immune system. If Hg affects the functioning of the immune system, exposed songbirds may be less able to mount an appropriate immune response against invading pathogens. To gain insight into how Hg affects songbird immune function on a cellular level, a flow cytometric assay was developed to measure lipopolysaccharide-induced B-lymphocyte proliferation in zebra finches (Taeniopygia guttata). This is the first experimental (dosing) study of the potential effect of Hg on songbird immune system functioning. Decreased B cell proliferation was observed after lipopolysaccharide exposure in individuals with greater concentrations of Hg in their blood and tissues. In addition, these individuals had decreased ratios of proliferating-to-resting B cells. This decrease in lymphocyte proliferation in response to an effective mitogen suggests that environmental exposure to sublethal levels of Hg may inhibit or delay B cell proliferation in songbirds, potentially increasing susceptibility to disease and decreasing survivorship.

A Combination of Micronucleus Assay and Fluorescence In Situ Hybridization Analysis to Evaluate the Genotoxicity of Formaldehyde by Sana Bouraoui; Soumaya Mougou; Aicha Brahem; Faten Tabka; Hela Ben Khelifa; Imed Harrabi; Najib Mrizek; Hatem Elghezal; Ali Saad (pp. 337-344).
A genotoxic effect of formaldehyde (FA), particularly micronucleus (MN) induction, has been shown in several previous studies. The aim of the present study was to assess the frequency of micronuclei and to identify the type of chromosomal damage in Tunisian staff members working in the Pathologic Anatomy Laboratory of Farhat Hached hospital (Sousse, Tunisia) who were exposed to FA. Assessment of chromosomal damage was performed in peripheral lymphocytes of 31 FA-exposed employees compared with 31 control employees working in the administrative department of the same hospital. The clastogenic/aneugenic effect of FA was evaluated using the standard MN assay in combination with fluorescence in situ hybridization (FISH) using pan-centromeric probes. The mean level of exposure to FA was 3.4 ppm. The results showed a significant increase of MN frequency in lymphocytes of exposed workers compared with the control group (25.35 ± 6.28 ‰ vs. 7.08  ± 4.62 ‰, p < 0.05). As assessed by FISH, the frequency of centromeric micronuclei (C+MN) was greater in exposed subjects than in controls (18.38 ± 5.94 ‰ vs. 5.03 ± 3.64 ‰). Among the C+MN, the frequency of MN containing one centromere (C1+MN) was significantly greater in pathologists and anatomists than in controls (15.35 ± 6.0 ‰ vs. 3.33 ± 2.74 ‰, p < 0.05). The results showed an effect of sex and time of FA exposure with significantly increased frequencies of all end points measuring aneuploidy (C+MN, C1+MN, and Cx+MN [more then one MN]). The increased frequency of C1+MN observed in the exposed group may suggest a slight aneugenic effect of FA exposure.
Featured Book
Web Search
Powered by Plone CMS, the Open Source Content Management System

This site conforms to the following standards: