Long-term Exposure Periods Research Articles

Analysis of Short and Long-Term Impacts of Petrochemical Effluents on Cattla Cattla Fish on Neelambur Pond, Coimbatore, Tamil Nadu, India

The study aimed to assess the impact of petrochemical effluent on fish blood, examining both short- term and long-term exposure periods to evaluate toxicity stress symptoms in the rapidly evolving petroleum industry. Various biochemical and hematological parameters, along with enzymatic changes, were analyzed by exposing different organs of freshwater fish, C. catla, to the petrochemical effluent. The results indicated a significant decrease in hemoglobin (Hb) content, red blood cells, packed cell volume, and mean corpuscular hemoglobin (MCH) values. Conversely, there was a notable increase in white blood cells (WBC) during the exposure periods compared to the control. Hematological parameters, including Hb, RBC, mean corpuscular volume (MCV), and MCH, exhibited fluctuating results, with a consistent decrease observed in both short- term (24, 48, 72, and 96 hours) and long-term (10, 20, and 30 days) exposure periods, suggesting the occurrence of anemia in the exposed fishes due to petrochemical effluent. In the biochemical analysis, exposed fish showed a significant reduction in protein, carbohydrate, and lipid content across all organs, accompanied by increased enzyme activity observed in all organs of freshwater fish, C. catla. Consequently, this survey is instrumental in predicting potential risks to the population and aquatic system.

Effect of Long-Term Low-Dose Arsenic Exposure on DNA Methylation and Gene Expression in Human Liver Cells.

Millions of people around the world are exposed to elevated levels of arsenic through food or drinking water. Epidemiological studies have linked chronic arsenic exposure to an increased risk of several cancers, cardiovascular disease, central nervous system neuropathies, and genotoxic as well as immunotoxic effects. In addition to the induction of oxidative stress and inhibition of DNA repair processes, epigenetic effects, including altered DNA methylation patterns resulting in aberrant gene expression, may contribute to carcinogenicity. However, the underlying mechanisms by which chronic micromolar concentrations of arsenite affect the methylation status of DNA are not fully understood. In this study, human HepG2 hepatocarcinoma cells were treated with 0.5-10 μM sodium arsenite for 24 h, 10, or 20 days. During these periods, the effects on global DNA methylation, cell cycle phase distribution, and gene expression were investigated. While no impact on DNA methylation was seen after short-term exposure, global hypomethylation was observed at both long-term exposure periods, with concomitant induction of the DNA methyltransferase genes DNMT1 and DNMT3B, while DNMT3A was slightly down-regulated. Pronounced time- and concentration-dependent effects were also seen in the case of genes involved in DNA damage response and repair, inflammation, oxidative stress response, and metal homeostasis. These results suggest that chronic low-dose arsenite exposure can lead to global hypomethylation. As an underlying mechanism, the consistent down-regulation of DNA methyltransferase genes could be excluded; alternatively, interactions at the protein level could play an important role.

Association of PM2.5 mass and its components with ovarian reserve in a northern peninsular province, China: The critical exposure period and components

BackgroundA possible role of PM2.5 components on ovarian reserve has not been adequately unexplored. ObjectiveTo evaluate the association between PM2.5 components and women’ ovarian reserve over critical exposure periods in northern China, where the level of air pollution is among the nation’s highest. MethodsWe included 15,102 women with serum anti-Müllerian hormone (AMH) measurements from the Center for Reproductive Medicine of Shandong University during 2015–2019. Concentrations of PM2.5 and its five major components (0.1° × 0.1°), including sulfate, nitrate, ammonium, organic matter, and black carbon, were assigned to each residential address. Multivariable linear mixed effect models combined with constituent-residual models were performed to estimate the effect sizes of essential components over six short- to long-term exposure periods. ResultsThe strength of association was stronger during the process from primary to small antral follicle compared with other longer windows. For every interquartile range increase in PM2.5 mass was associated with − 8.7% (95%CI: −12.3%, −4.9%) change in AMH and the effect size was greatest for sulfate. Women with the lower level of attained education and those living inland were more susceptible compared with other population subgroups. ConclusionExposure to specific components of air pollution during critical exposure windows is associated with a decline in ovarian reserve. These data add to the growing body of evidence that environmental factors have adverse effects on reproductive health, particularly for vulnerable population subgroups.

Diagonal compression testing of masonry under fatigue loading and high static loads

Underground railway operations pose a significant impact on overlying, highly sensitive historic masonry structures. Here, the process of structural assessment involves fatigue actions, through induced ground-borne vibrations, from operating underground railways. Considering long-term exposure periods, fatigue can introduce local cracking and losses, which endanger the integrity of both structural and non-structural elements. The lack of experimental fatigue data on tensile actions in masonry and the apparent computational restraints from constitutive cementitious material models that do not account for damage due to repeated loading, increase the complexity of structural assessment, under combined fatigue actions and other hazards. The current paper aims at providing new experimental data on fatigue in historic brick and lime mortar masonry wallets, replicating realistic combinations of static and fatigue loading under diagonal compression. Material deterioration and stiffness degradation are monitored throughout the process. Hence, under moderate amplitudes of fatigue loading and high static loads, cracking occurred, at a relatively low number of cycles, demonstrating the need for more strict vibration thresholds to ensure the integrity of historic masonry buildings.

Field recommended concentrations of pyraclostrobin exposure disturb the development and immune response of worker bees (Apis mellifera L.) larvae and pupae.

The strobilurin fungicide pyraclostrobin is widely used to prevent and control the fungal diseases of various nectar and pollen plants. Honeybees also directly or indirectly contact this fungicide with a long-term exposure period. However, the effects of pyraclostrobin on the development and physiology of Apis mellifera larvae and pupae during continuous exposure have been rarely known. To investigate the effects of field-realistic concentrations of pyraclostrobin on honeybee survival and development, the 2-day-old larvae were continuously fed with different pyraclostrobin solutions (100mg/L and 83.3mg/L), and the expression of development-, nutrient-, and immune-related genes in larvae and pupae were examined. The results showed that two field-realistic concentrations of pyraclostrobin (100 and 83.3mg/L) significantly decreased the survival and capped rate of larvae, the weight of pupae and newly emerged adults, and such decrease was a positive correlation to the treatment concentrations. qPCR results showed that pyraclostrobin could induce the expression of Usp, ILP2, Vg, Defensin1, and Hymenoptaecin, decrease the expression of Hex100, Apidaecin, and Abaecin in larvae, could increase the expression of Ecr, Usp, Hex70b, Vg, Apidaecin, and Hymenoptaecin, and decreased the expression of ILP1, Hex100 and Defensin1in pupae. These results reflect pyraclostrobin could decrease nutrient metabolism, immune competence and seriously affect the development of honeybees. It should be used cautiously in agricultural practices, especially in the process of bee pollination.

Efeitos do pré-resfriamento e armazenamento a frio no sistema antioxidante na pós-colheita de copo-de-leite

ABSTRACT Low-temperature storage is one of the most effective techniques to maintain the quality and durability of cut flowers. Both quality maintenance and durability are dependent on plant metabolism factors such as antioxidant system. The objective was to evaluate the effect of low-temperature on precooling and storage after harvest, on the metabolism of calla lily [Zantedeschia aethiopica (L.) K. Spreng] concerning the antioxidant system, levels of hydrogen peroxide (H2O2), and malondialdehyde (MDA). Therefore, different storage temperatures (4 ºC and 21 ºC) were tested as well as the effect of precooling in different periods (0 to 24 hours). It was observed that the activity of catalase (CAT) and superoxide dismutase (SOD) was increased at 4 °C, as well as inflorescence durability in the commercial standard (around 12 days). At 21 °C, the content of H2O2 and MDA was higher and the visual quality reduction in the inflorescence was accelerated. Low-temperature leads to a higher activity of the enzymes of the antioxidant system (CAT and SOD) and increases postharvest longevity for calla lily. Precooling did not influence the visual quality and longevity of calla lily. Long-term exposure periods at low temperatures, with 12 and 24 hours of precooling caused stress, evidenced higher MDA levels and higher CAT activity. SOD activity was related to low temperature and shorter precooling periods resulted in better antioxidant system activity and lower MDA levels.

Toxicity of Different Types of Surfactants via Cellular and Enzymatic Assay Systems.

Surfactants have a widespread occurrence, not only as household detergents, but also in their application in industry and medicine. There are numerous bioassays for assessing surfactant toxicity, but investigations of their impact on biological systems at the molecular level are still needed. In this paper, luminous marine bacteria and their coupled NAD(P)H:FMN-oxidoreductase + luciferase (Red + Luc) enzyme system was applied to examine the effects of different types of surfactants, including cationic cetyltrimethylammonium bromide (CTAB), non-ionic polyoxyethylene 20 sorbitan monooleate (Tween 80) and anionic sodium lauryl sulfate (SLS), and to assess whether the Red + Luc enzyme system can be used as a more sensitive indicator of toxicity. It was shown that the greatest inhibitory effect of the surfactants on the activity of luminous bacteria and the Red + Luc enzyme system was in the presence of SLS samples. The calculated IC50 and EC50 values of SLS were 10-5 M and 10-2 M for the enzymatic and cellular assay systems, respectively. The results highlight the benefits of using the enzymatic assay system in ecotoxicology as a tool for revealing surfactant effects on intracellular proteins if the cellular membrane is damaged under a long-term exposure period in the presence of the surfactants. For this purpose, the bioluminescent enzyme-inhibition-based assay could be used as an advanced research tool for the evaluation of surfactant toxicity at the molecular level of living organisms due to its technical simplicity and rapid response time.

Cytogenetic study of dental diagnostic x-ray workers

Background and Objectives: studying chromosome changes for dental x-ray workers in the city of kut and diagnosing those abnormalities resulting from continuous exposure to radiation. Exposure and Methods: The chromosomes of those exposed to dental X-rays were analyzed and studied using cytogenetic analysis to detect chromosomal aberrations caused by ionizing radiation after collecting blood samples from those exposed to Al-Zahraa and Al-Karama Teaching Hospital as well as from the Taiba Specialized Center in addition to the dental clinics in Wasit. Results: Chromosomal analysis of all subjects showed chromosomal aberrations, and most of the aberrations were structural changes that were divided according to the ratio of their frequencies. The largest percentage was for the gap chromosome type (44%), chromosomal-aberration dicentric (16%) and chromosomal-aberration gab and dicentric (8%). Conclusion: Dental diagnostic x-rays have an effect on the chromosomes of workers exposed to a long-term cumulative exposure period, as it leads to the appearance of aberrations of the type chromosomal aberration (gab chromatid ) is the most frequent in this stuy.

Acid, alkali and chloride resistance of binary, ternary and quaternary blended cementitious mortar integrated with nano-silica particles

This paper investigates the quantification of ettringite (Ca6Al2(SO4)3(OH)12.26H2O, AFt), gypsum (CaSO4.2H2O, Gy) and Friedel's salt (Ca4Al2(OH)12Cl2.4H2O, Fs) formed for binary, ternary and quaternary blended cementitious mortar mixes that were exposed to acid (H2SO4), alkali (Na2SO4) and chloride (NaCl) solutions. Quantification was carried out through a thermogravimetric analyzer by characterizing the mass loss associated to the decomposition of these compounds at specific boundaries of temperature (50–120 °C for AFt, 120–150 °C for Gy and 230–380 °C for Fs). Binary, ternary and quaternary blended cementitious mortar mixes were designed by adopting modified Andreasen and Andersen particle packing model. A long-term exposure period was spanned to the duration of 180 days for all kind of aggressive media and its effect on engineering properties of blended cementitious mortar were measured. Deterioration due to acid (H2SO4) exposure is found to be more intense due to the synergistic action of acid and sulfates. It is to be noted that for acid exposure period of 180 days, control mortar underwent an acute density and strength losses of 18% and 59%, respectively. However, cementitious mortar mix consisting of 3% nano-silica performs the best against aggressive media. The optimistic resistance to the formation of AFt and Gy was also found to be offered by quaternary blended mix. A similar trend was also observed in the formation of Fs for the mortar mixes exposed to NaCl solution. Significant improvement in particle packing density by the inclusion of micron to nano sized finer particles for quaternary blended mortar mix has minimized the permeable porosity, thus reduced the susceptibility to the formation of voluminous compounds. Enhanced pozzolanic activity due to the presence of nano-silica could be one of the primary reasons for quaternary blended mortar to perform better against the aggressive media that can be adopted in the practice considering sustainability and economical point of view.

Organophosphorus-based chemical additives induced behavioral changes in zebrafish (Danio rerio): Swimming activity is a sensitive stress indicator

Organophosphorus flame retardants (OPFRs) have been extensively used as chemical additives in polymer based consumer products. Among them, Isopropylphenyl phosphate (IPPP) and tripropyl phosphate (TPP) are predominant, which have potential to cause neuro-toxic effects on non-target organisms. As behavior (swimming activity) response is the first adjustment due to neurotoxic stress on the fitness of fish. In this study, the quantified swimming activity of zebrafish (Danio rerio) under IPPP and TPP exposure in an online monitoring system was investigated to assess the neurotoxin effects under long-term exposure periods, no swimming anomalies were observed in the control group. Whereas, in the OPFR exposures ((treatment I: 5 μg/L and treatment II: 25 μg/L), a series of anomalies were identified. Hyperactivity was shown in IPPP treatment I group (5 μg/L), whereas zebrafish swimming activity was declined throughout the study period in IPPP treatment II (25 μg/L), and TPP groups (5 μg/L and 25 μg/L) when compared to the control group. Circadian rhythm was not affected in the present study. The results of the present study indicated that the fitness of test individuals was a valid biomarker for eco-toxicity assessment under unescapable conditions. Hypoactivity of zebrafish signified the neurotoxic effects of IPPP and TPP. A concentration based improvement in swimming activity was observed under recovery conditions, which suggested that recovery capacity along with toxicity responses could be a comprehensive non-invasive technique to assess the eco-toxicity of waterborne chemicals.

Variability of urinary pyrethroid biomarkers in Chinese young-aged men and women over one year.

Pyrethroids are a class of the most commonly used insecticides. The urinary metabolites are usually used as biomarkers of pyrethroid exposures in humans. In this study, the temporal variability of urinary pyrethroid biomarkers was investigated among 114 Chinese young-aged adults who provided up to 4-11 urine samples over one year. The detection rates of four urinary pyrethroid biomarkers, 3-phenoxybenzoic acid (3PBA), 4-fluoro-3-phenoxybenzoic acid (4F-3PBA), trans-2,2-(dichloro)-2-dimethylvinylcyclopropane carboxylic acid (trans-DCCA) and cis-2,2-(dichloro)-2-dimethylvinylcyclopropane carboxylic acid (cis-DCCA) were 100%, 8%, 69% and 44%, respectively. The intraclass correlation coefficient (ICC) estimates for 3PBA indicated poor reproducibility (<0.15) in the spot urine samples of young-aged adults over a week, month and year. Log-transformed 3PBA used the least number of random spot urine samples (≥4) per person, which would provide a reliable biomarker estimate (ICC≥0.40) over a year. As the predictors of the top 33% yearly average 3PBA concentrations, the sensitivity and specificity of 3PBA ranged from 0.25 to 0.89, 0.58 to 0.96, respectively. Based on the results of this study, we recommend at least 4 urine samples collected 3 months apart for prospective assessment of pyrethroid exposure in the epidemiological studies to estimate exposure-response relationships between pyrethroids and health outcomes with relative long-term exposure periods.

Long-term air pollution exposure and self-reported morbidity: A longitudinal analysis from the Thai cohort study (TCS)

BackgroundSeveral studies have shown the health effects of air pollutants, especially in China, North American and Western European countries. But longitudinal cohort studies focused on health effects of long-term air pollution exposure are still limited in Southeast Asian countries where sources of air pollution, weather conditions, and demographic characteristics are different. The present study examined the association between long-term exposure to air pollution and self-reported morbidities in participants of the Thai cohort study (TCS) in Bangkok metropolitan region (BMR), Thailand. MethodsThis longitudinal cohort study was conducted for 9 years from 2005 to 2013. Self-reported morbidities in this study included high blood pressure, high blood cholesterol, and diabetes. Air pollution data were obtained from the Thai government Pollution Control Department (PCD). Particles with diameters ≤10 μm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), and carbon monoxide (CO) exposures were estimated with ordinary kriging method using 22 background and 7 traffic monitoring stations in BMR during 2005–2013. Long-term exposure periods to air pollution for each subject was averaged as the same period of person-time. Cox proportional hazards models were used to examine the association between long-term air pollution exposure with self-reported high blood pressure, high blood cholesterol, diabetes. Results of self-reported morbidity were presented as hazard ratios (HRs) per interquartile range (IQR) increase in PM10, O3, NO2, SO2, and CO. ResultsAfter controlling for potential confounders, we found that an IQR increase in PM10 was significantly associated with self-reported high blood pressure (HR = 1.13, 95% CI: 1.04, 1.23) and high blood cholesterol (HR = 1.07, 95%CI: 1.02, 1.12), but not with diabetes (HR = 1.05, 95%CI: 0.91, 1.21). SO2 was also positively associated with self-reported high blood pressure (HR = 1.22, 95%CI: 1.08, 1.38), high blood cholesterol (HR = 1.20, 95%CI: 1.11, 1.30), and diabetes (HR = 1.21, 95%CI: 0.92, 1.60). Moreover, we observed a positive association between CO and self-reported high blood pressure (HR = 1.07, 95%CI: 1.00, 1.15), but not for other diseases. However, self-reported morbidities were not associated with O3 and NO2. ConclusionsLong-term exposure to air pollution, especially for PM10 and SO2 was associated with self-reported high blood pressure, high blood cholesterol, and diabetes in subjects of TCS. Our study supports that exposure to air pollution increases cardiovascular disease risk factors for younger population.

Organophosphorus flame retardant induced hepatotoxicity and brain AChE inhibition on zebrafish (Danio rerio)

Organophosphorus flame retardants (OPFRs) are high production volume (HPV) chemicals. Recent reports reveal that OPFRs are ubiquitous in the environment. Unfortunately, the toxicity profiles for OPFRs on organisms remain limited. Hence, to illustrate the potential toxic effects of OPFRs at environmental relevant concentrations on aquatic biota, in the present study, we investigated biochemical, enzymological, antioxidants, and histological (at long-term study) changes of zebrafish tissues under short- (96 h) and long- (21 days) -term triphenyl phosphate (TPhP) exposure. The hepatic glucose production (except short-term TPhP treatment up to 48 h), aspartate transaminase, alanine transaminase, lactate dehydrogenase, reactive oxygen species generation, lipid peroxide, and catalase activities were found to be increased in TPhP exposed groups when compared to control groups (normal and solvent control groups). The hepatic protein content and sodium dismutase activity were declined in TPhP exposed groups. Likewise, brain tissue acetylcholinesterase activity was declined in TPhP exposed groups. The hepatic glutathione S-transferase activity increased after 24 h under short-term TPhP exposure (96 h), while under long-term exposure period (21 days) the enzyme activity was accelerated when compared to control groups. Long-term TPhP exposure resulted in a series of morphological anomalies in the hepatic tissues of zebrafish. Our study reveals that TPhP can potentially cause antioxidants imbalance, alterations in enzymological and biochemical profiles, and morphological anomalies in hepatic tissues of zebrafish. Moreover, TPhP could cause neurotoxic effects on zebrafish at studied concentrations. Our findings expand the available toxicity profiles for TPhP on aquatic biota and propose that zebrafish are a good indicator, and studied parameters are valid biomarkers in assessing the eco-toxicological effects of OPFRs.

The physiological response of the deep-sea coral Solenosmilia variabilis to ocean acidification.

Several forms of calcifying scleractinian corals provide important habitat complexity in the deep-sea and are consistently associated with a high biodiversity of fish and other invertebrates. How these corals may respond to the future predicted environmental conditions of ocean acidification is poorly understood, but any detrimental effects on these marine calcifiers will have wider impacts on the ecosystem. Colonies of Solenosmilia variabilis, a protected deep-sea coral commonly occurring throughout the New Zealand region, were collected during a cruise in March 2014 from the Louisville Seamount Chain. Over a 12-month period, samples were maintained in temperature controlled (∼3.5 °C) continuous flow-through tanks at a seawater pH that reflects the region’s current conditions (7.88) and an end-of-century scenario (7.65). Impacts on coral growth and the intensity of colour saturation (as a proxy for the coenenchyme tissue that covers the coral exoskeleton and links the coral polyps) were measured bimonthly. In addition, respiration rate was measured after a mid-term (six months) and long-term (12 months) exposure period. Growth rates were highly variable, ranging from 0.53 to 3.068 mm year−1 and showed no detectable difference between the treatment and control colonies. Respiration rates also varied independently of pH and ranged from 0.065 to 1.756 µmol O2 g protein−1 h−1. A significant change in colour was observed in the treatment group over time, indicating a loss of coenenchyme. This loss was greatest after 10 months at 5.28% and could indicate a reallocation of energy with physiological processes (e.g. growth and respiration) being maintained at the expense of coenenchyme production. This research illustrates important first steps to assessing and understanding the sensitivity of deep-sea corals to ocean acidification.

Effect of long-term exposure to air pollution on anxiety and depression in adults: A cross-sectional study.

The association between exposure to air pollutants and mental disorders among adults has been suggested, although results are not consistent. To analyze the association between long-term exposure to air pollution and history of anxiety and depression disorders and of medication use (benzodiazepines and antidepressants) in adults living in Barcelona. A total of 958 adults (45-74 years old) residents in Barcelona, most of them having at least one of their parents diagnosed with dementia (86%), and participating in the ALFA (Alzheimer and Families) study, were included. We used Land Use Regression (LUR) models to estimate long-term residential exposure (period 2009-2014) to PM2.5, PM2.5 absorbance (PM2.5 abs), PM10, PM coarse, NO2 and NOx. Between 2013 and 2014 participants self-reported their history of anxiety and depression disorders and related medication use. The analysis was focused on those participants reporting outcome occurrence from 2009 onwards (until 2014). We observed an increased odds of history of depression disorders with increasing concentrations of all air pollutants [e.g. an increased odds of depression of 2.00 (95% CI; 1.37, 2.93) for each 10μg/m3 NO2 increase]. Such associations were consistent with an increased odds of medication use in relation to higher concentrations of air pollutants [e.g. an increased odds of antidepressants use of 1.23 (1.04, 1.44) for each 20μg/m3 NOx increase]. Associations regarding anxiety disorders did not reach statistical significance. Our study shows that increasing long-term exposure to air pollution may increase the odds of depression and the use of antidepressants and benzodiazepines. Further studies are needed to replicate our results and confirm this association.

The stability and fate of synthesized zero-valent iron nanoparticles in freshwater microcosm system.

Zero-valent iron nanoparticles are used for the degradation of organic compounds and the immobilization of metals and metalloids. The lack of information on the effect of nZVI in freshwater system necessitated the risk assessment of zero-valent iron nanoparticles in lake water environment. The present study deals with the stability and fate of synthesized zero-valent iron nanoparticles in the upper and lower layers of freshwater microcosm system at a concentration of 1000mgL-1. The study was divided into two different exposure periods: short-term exposure, up to 24h after the introduction of nanoparticles, and long-term exposure period up to 180days (4416h). Aggregation kinetics of nZVI in freshwater microcosm was studied by measuring the mean hydrodynamic size of the nanoparticles with respect to time. A gradual increase in the particle size with time was observed up to 14h. The algal population and total chlorophyll content declined for the short exposure period, i.e., 2-24h, while in the case of longer exposure period, i.e., 24h to 180days (4416h), a gradual increase of both the algal population and total chlorophyll was noted. Five different physico-chemical parameters such as pH, temperature, conductivity, salinity, and total dissolved solids were recorded for 180days (6 calendar months). The study suggested that the nanoscale zero-valent iron did not exhibit significant toxicity at an exposure concentration of 1000mgL-1 on the resident algal population in the microcosm system over the longer exposure period tested.

THE USE OF EFFECTIVE MICROORGANISMS (EM) AS A PROBIOTIC ON CULTURED NILE TILAPIA; OREOCHROMIS NILOTICUS

Nowadays, and due to different anthropogenic activities, the environmental conditions deteriorate and consequently productivity of cultured and wild fish decreases. The present study highlights the role of effective microorganisms (EM) as a probiotic in enhancing biological features and growth performance of the cultured Nile tilapia (Oreochromis niloticus) exposed to copper metal under experimental conditions. Other metals that may interfere with toxic effects of copper on fish were measured. The conducted toxicity test showed that the copper 96hr LC50 is 6.30 mg/l, thus fish of the experimental groups were exposed to 0.1 of that dose (0.630 mg/l) as a sublethal chronic dose for 12 weeks. After this long-term exposure period, metal concentrations in gills, liver, kidney, muscles and skin of O. niloticus showed significant increase in the copper exposed group associated with histopathological changes and clear damage in gills, liver and kidney tissues comparing to the EM exposed group. Moreover, the results revealed significant improvement in growth indices, histological and biochemical aspects of EM exposed fish. The present study recommends the use of effective microorganisms in fish farms to enhance fish productivity and reduce the toxic effects of pollutants.

Toxicological effects of clofibric acid and diclofenac on plasma thyroid hormones of an Indian major carp, Cirrhinus mrigala during short and long-term exposures

In the present investigation, the toxicity of most commonly detected pharmaceuticals in the aquatic environment namely clofibric acid (CA) and diclofenac (DCF) was investigated in an Indian major carp Cirrhinus mrigala. Fingerlings of C. mrigala were exposed to different concentrations (1, 10 and 100μgL−1) of CA and DCF for a period of 96h (short term) and 35 days (long term). The toxic effects of CA and DCF on thyroid hormones (THs) such as thyroid stimulating hormone (TSH), thyroxine (T4) and triiodothyronine (T3) levels were evaluated. During the short and long-term exposure period TSH level was found to be decreased at all concentrations of CA (except at the end of 14th day in 1 and 10μgL−l and 21st day in 1μgL−l) whereas in DCF exposed fish TSH level was found to be increased when compared to control groups. T4 level was found to be decreased at 1 and 100μgL−l of CA exposure at the end of 96h. However, T4 level was decreased at all concentrations of CA and DCF during long-term (35 days) exposure period. Fish exposed to all concentrations of CA and DCF had lower level of T3 in both the treatments. These results suggest that both CA and DCF drugs induced significant changes (P<0.01 and P<0.05) on thyroid hormonal levels of C. mrigala. The alterations of these hormonal levels can be used as potential biomarkers in monitoring of pharmaceutical drugs in aquatic organisms.

Use of Tradescantia clone 4430 for direct long-term soil mutagenicity studies

Soil mutagens permanently and directly affect terrestrial plants, soil microorganisms and invertebrates and indirectly impact vertebrate and human populations. However, the dynamic response to soil mutagens under conditions of long-term exposure has been studied insufficiently. The clonal nature of Tradescantia #4430 and the well-developed associated test systems for evaluation of genotoxicity allow investigation of the permanent effects of direct exposure to the soil not only on plants of the same genotype, but even with the same individual plants, as was done in the present study. Twenty soil samples of different origin were studied in Tradescantia after 0.5, 1 and 2 years of direct exposure to the soil, in order to examine the induction of pink cells (PC), colorless cells (CC) and branched hairs (BH). Additionally, after 0.5 years, micronucleus (MN) formation was assessed, and after 1 year, the variation of random amplified polymorphic DNA (RAPD) markers was evaluated. Nine soil samples were of urban origin, and the others came from different soils from former military grounds. The results of the 0.5-year exposure were compared with the effects of aqueous/DMSO extracts tested in previous work. The long-term exposure period allowed not only a better differentiation of the soils within territories, but also permitted detection of differences between soils of urban and military origin. The results also depended on the test used to evaluate genotoxicity. The ‘burst’ phenomenon, consisting of a sudden increase of BH variation and, especially, of CC, was observed only in tests of samples from several military sites, mainly after a 2-year exposure. MN formation was less frequent after 0.5 years of exposure compared with the results from aqueous extracts, and this difference was highly significant. The variation of the RAPD markers in a significant portion of the soil samples coincided with a higher level of variation according to other tests (PC, CC, BH), but predicting the genotoxicity of the soils based on their elemental soil composition at the end of the experiment was impossible. At several points where a ‘burst’ was observed, the concentration of a number of elements was lower. A cumulative effect is hypothesized to explain these observations. Tradescantia clone #4430 is the most suitable system for such studies.

Monocrotophos induced toxicity and physiological stress on fish Puntius filamentosus. (Val, 1844)

The effect of lethal (26.5µl/l) and sub-lethal (2.65µl/l) concentrations of monocrotophos (36% SL) on oxygen consumption and behavior of the fish Puntius filamentosus were studied in the laboratory. The oxygen consumption level was drastically reduced in lethal concentration and no much difference was seen at sub- lethal concentration. Similarly, in lethal concentration, the fish behaved abnormally with abnormal swimming pattern and eventually died. In sub-lethal concentration a little difference was seen in the behavior of the fish for the first 4 days but later on the fish adapted to the surrounding environment. The study reveals that the fish P. filamentosus can adapt to low concentration of monocrotophos toxicity during long-term exposure periods but the increase in concentration is toxic to the fish.