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The cytotoxicity and DNA damage of titanium dioxide and zinc oxide nanoparticles (TiO2 and ZnO NPs) have been studied in a human lung carcinoma cell line (A549) after 24 h exposure. TiO2 and ZnO NPs had mean diameters of 12.9 ± 2.8 and 24.1 ± 8.0 nm, respectively. ZnO NPs reduced cell viability from 250 μg/mL, increasing reactive oxygen species (ROS) and decreased GSH/GSSG ratio. The comet assay detected DNA damage from 50 μg/mL. TiO2 NPs induced cytotoxicity and DNA damage from 50 to 100 μg/mL, respectively, along with a decrease of the GSH/GSSG ratio. Both particles were found inside the cells, within membrane-bound vesicles. The internalization mechanism is promoted partially by caveolae-mediated endocytosis and, in the case of TiO2 NPs, also by macropinocytosis.

Cadmium (Cd) and its compounds are well-known human carcinogens, but the mechanisms underlying the carcinogenesis are not well understood. This study aimed to investigate whether long noncoding RNA (LncRNA)–ENST00000446135 could serve as a novel biomarker of Cd toxicity in cells, animals, and Cd-exposed workers and regulate DNA damage and repair. LncRNA–ENST00000446135 expression increased gradually in cadmium chloride-transformed 16HBE cells. Small interfering RNA-mediated knockdown of LncRNA–ENST00000446135 inhibited the growth of DNA-damaged cells and decreased the expressions of DNA damage-related genes (ATM, ATR, and ATRIP), whereas increased the expressions of DNA repair-related genes (DDB1, DDB2, OGG1, ERCC1, MSH2, XRCC1, and BARD1). Chromatin immunoprecipitation-sequencing showed that MSH2 is a direct transcriptional target of lncRNA–ENST00000446135. Cadmium increased lncRNA–ENST00000446135 expression in the lung of Cd-exposed rats in a dose-dependent manner. A significant positive correlation was observed between blood ENST00000446135 expression and urinary/blood Cd concentrations, and there were significant correlations of LncRNA–ENST00000446135 expression with the DNA damage cell and the expressions of target genes in the lung of Cd-exposed rats and the blood of Cd-exposed workers and significantly correlated with liver and renal function in Cd-exposed workers. These results indicate that the expression of LncRNA–ENST00000446135 is upregulated and may serve as a signature for DNA damage and repair related to the epigenetic mechanisms underlying the cadmium toxicity and become a novel biomarker of cadmium toxicity.

Formaldehyde (FA) exposure has been proven to increase the risk of asthma and cancer. This study aimed to evaluate for 28 days the FA inhalation effects on oxidative stress, inflammation process, genotoxicity, and global DNA methylation in mice as well as to investigate the potential protective effects of melatonin. For that, analyses were performed on lung, liver and kidney tissues, blood, and bone marrow. Bronchoalveolar lavage was used to measure inflammatory parameters. Lipid peroxidation (TBARS), protein carbonyl (PCO), non-protein thiols (NPSH), catalase activity (CAT), comet assay, micronuclei (MN), and global methylation were determined. The exposure to 5-ppm FA resulted in oxidative damage to the lung, presenting a significant increase in TBARS and NO levels and a decrease in NPSH levels, besides an increase in inflammatory cells recruited for bronchoalveolar lavage. Likewise, in the liver tissue, the exposure to 5-ppm FA increased TBARS and PCO levels and decreased NPSH levels. In addition, FA significantly induced DNA damage, evidenced by the increase of % tail moment and MN frequency. The pretreatment of mice exposed to FA applying melatonin improved inflammatory and oxidative damage in lung and liver tissues and attenuated MN formation in bone marrow cells. The pulmonary histological study reinforced the results observed in biochemical parameters, demonstrating the potential beneficial role of melatonin. Therefore, our results demonstrated that FA exposure with repeated doses might induce oxidative damage, inflammatory, and genotoxic effects, and melatonin minimized the toxic effects caused by FA inhalation in mice.

Quantitative mechanistic modeling of the biological effects of ionizing radiation has a long rich history. Initially, it was dominated by target theory, which quantifies damage caused by traversal of cellular targets like DNA by ionizing tracks. The discovery that mutagenesis, death and/or altered behavior sometimes occur in cells that were not themselves traversed by any radiation tracks but merely interacted with traversed cells was initially seen as surprising. As more evidence of such ‘non-targeted’ or ‘bystander’ effects accumulated, the importance of their contribution to radiation-induced damage became more recognized. Understanding and modeling these processes is important for quantifying and predicting radiation-induced health risks. Here we review the variety of mechanistic mathematical models of nontargeted effects that emerged over the past 2–3 decades. This review is not intended to be exhaustive, but focuses on the main assumptions and approaches shared or distinct between models, and on identifying areas for future research.

Triple negative breast carcinoma (TNBC) is an aggressive form of cancer, with high rates of morbidity, mortality, poor prognosis and limited therapeutic options. The objective of the present study was to elaborate the anticancer activity of Troxerutin (TXN) in TNBC/MDA-MB-231 cells. Herein, we demonstrated the inhibitory effects of TXN on the breast cancer cell growth via induction of apoptosis. Mitochondrial membrane potential (∆Ψm), DNA damage and apoptotic nuclear changes were analyzed by flowcytometry, AO/EtBr and Hoechst staining, respectively. Furthermore, apoptotic protein and gene expressions were analyzed by western blot and reverse transcription polymerase chain reaction (RT-PCR), respectively. Our results indicated that TXN induces apoptosis as evidenced by inhibit the cell proliferation, enhanced apoptotic activation, altered mitochondrial membrane potential and elevated level of DNA damage in TNBC cells. Furthermore, the TXN inhibit anti-apoptotic protein expression with the subsequent upregulation of Cytochrome c, Caspase-9 and Caspase-3. Thus, TXN induces apoptosis in TNBC cells through inducing nuclear damage and altered apoptotic marker expressions. Therefore, TXN might be used as a potential therapeutic agent for the treatment of triple negative breast cancer.

Detection and characterization of DNA damage plays a critical role in genotoxicity testing, drug screening, and environmental health. We developed a fully integrated origami paper-based analytical device (oPAD) for measuring DNA damage. This simple device allows on-paper cell lysis, DNA extraction, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) reaction and signal readout with simple operation steps, enabling rapid (within 30 min) and high throughput assessment of multiple DNA damages induced by exogenous chemical agents.

One of the most common usages of radiation in current medical diagnosis is computed tomography (CT) using X-rays. The potential health risk of CT scans has been discussed in various studies to determine whether low-dose radiation from CT could enhance the chromosome aberration yields in pediatric patients and increase their risk of carcinogenesis. For this reason, it is of great interest to study the effects of low-dose radiation. The induction of DNA damage by a CT scan examination has been demonstrated in several reports by the γ-H2AX assay, the micronuclei assay and dicentrics measurements. However, the results of most studies showed limitations. On the other hand, epidemiological studies give contradictory results for post-natal radiation exposure in the low-dose range, so it is still difficult to draw conclusions about the effects of CT examinations and risk of carcinogenesis. This article provides an overview of previously published data and summarizes the current state of knowledge.

International audience; Ionizing radiation is a peculiar perturbation when it comes to damage to biological systems it proceeds through discrete energy depositions, over a short temporal scale and a spatial scale critical for subcellular targets as DNA, whose damage complexity determines the outcome of the exposure. This lies at the basis of the success of track structure (and nanodosimetry) and microdosimetry in radiation biology. However, such reductionist approaches cannot account for the complex network of interactions regulating the overall response of the system to radiation, particularly when effects are manifest at the supracellular level and involve long times. Systems radiation biology is increasingly gaining ground, but the gap between reductionist and holistic approaches is becoming larger. This paper presents considerations on what roles track structure and microdosimetry can have in the attempt to fill this gap, and on how they can be further exploited to interpret radiobiological data and inform systemic approaches. © The Author(s) 2018. Published by Oxford University Press.

In recent years, increasing efforts have focused on production of organic-inorganic compound fertilizers using ammonium sulfite pulping waste liquor. However, their ecological effects on soil have not been studied. In this study, earthworm Eisenia fetida was exposed to various doses (0, 0.13, 0.26 and 0.52 kg/m2) for different time (7, 14, 21, and 28 d) to evaluate the effects of fertilizers made from pulping waste liquor, including reactive oxygen species (ROS) generation, antioxidant enzymes activities, glutathione S-transferase enzyme (GST) activity, malondialdehyde (MDA) content and DNA damage. Results showed that there were significant increase of ROS and MDA levels after 14 d, inducing production of antioxidant enzymes (superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT)) as well as GST. Before 14 d, excess ROS and MDA caused damage to the DNA of earthworms, leading to gradual increase of Olive tail moment (OTM) in the comet assay. With the exposure time extended to 28 d, owing to the combined effects of elimination of free radicals by antioxidant enzymes and detoxification enzymes as well as self-repairing function of cells, ROS and MDA levels declined slightly and OTM gradually decreased. In summary, this study indicated that there was a toxicological effect on earthworms when fertilizers made from pulping waste liquor were applied to soil, which needs more attention.

Lake Van fish (Alburnus tarichi Guldenstadt 1814) is the only fish that can adapt to the extreme conditions (pH 9.8 salinity 0.2% and alkalinity 151.2 meq/L) of Lake Van. In this study, it was aimed to determine the cytotoxic and genotoxic effects of chlorpyrifos (CPF) on Lake Van fish primary gill cell culture. Gill epithelium from Lake Van fish was isolated enzymatically and grown in primary culture on Leibovitz’s L-15 medium. After different doses (0.01, 0.1, 1, and 10 μM) of CPF were applied to the gill cells, the total oxidant status (TOS), total antioxidant status (TAS), malondialdehyde (MDA), and DNA damage levels (8-hydroxyguanine (8-OHdG)) were examined at the end of 24 and 48 h. It was determined that the TOS, MDA, and 8-OHdG levels increased in the cells exposed to high doses (1 and 10 μM) of CPF and the TAS was decreased (P

Radiation dosimeters are critical for accurately assessing the levels of radiation exposure of tumor sites and surrounding tissues and for optimizing therapeutic interventions as well as for monitoring environmental exposure. To fill the need for a simple, user-friendly, and inexpensive dosimeter, we designed an innovative colorimetric nanosensor-based assay for detecting ionizing radiation. We show that hydroxyl radicals generated by ionizing radiation can be used to etch gold nanorods (AuNRs) and silver nanoprisms (AgNPRs), yielding reproducible color changes for radiation dose detection in the range of 50–2000 rad, broad enough to cover doses used in hyperfractionated, conventional, and hypofractionated radiotherapy. This range of doses detected by this assay correlates with radiation-induced DNA damage response in mammalian cells. Furthermore, this AuNR- and AgNPR-based sensing platform has been established in a paper format that can be readily adopted for a wide range of applications and translation.

Paper mill effluents are complex mixtures containing different toxic compounds including endocrine-disrupting (EDCs) and genotoxic compounds. In the present study non-concentrated raw and biologically treated wastewaters from two paper mill plants with different paper production technologies i) Paper mill A uses virgin fibres, and ii) Paper mill B uses recycled fibres for paper production and the corresponding receiving surface waters, were assessed for their cytotoxic/genotoxic activity with SOS/umuC, Ames MPF 98/100 Aqua, and comet assay with human hepatoma HepG2 cells. In addition the levels of seven selected EDCs were quantified in wastewater samples and receiving surface waters. All investigated EDCs were confirmed in raw and biologically treated effluents from both paper mills with concentrations being markedly higher in Paper mill B effluents. In the receiving surface waters three of the studied EDCs were determined downstream of both paper mills effluent discharge. The wastewater samples and the recipient surface water samples from Paper mill A were not mutagenic for bacteria and did not induce DNA damage in HepG2 cells. On the contrary, half of the raw wastewater samples from Paper mill B were mutagenic whereas biologically treated wastewater and the recipient surface water samples were negative. In HepG2 cells most of the raw and biologically treated wastewater samples from Paper mill B as well as surface water samples collected downstream of Paper mill B effluent discharge induced DNA damage. The results confirmed that genotoxic contaminants were present only in wastewaters from Paper mill B that uses recycled fibres for paper production, and that the combined aerobic and anaerobic wastewater treatment procedure efficiently reduced contaminants that are bacterial mutagens, but not those that induce DNA damage in HepG2 cells. This study highlights that in addition to chemical analyses bioassays are needed for a comprehensive toxicological evaluation of complex wastewater samples.

Objective To explore the genetic damage caused by different tar levels in the human body. Methods The subjects were divided into high, medium and low (12 mg, 8 mg, 5 mg) tar groups according to the tar levels. Nonsmoking populations served as a control group. 2 ml of peripheral blood was collected on the 10th day after morning fasting. Oxidative and genetic toxicological damage indicators were analysed with enzyme-linked immunosorbent assay, cytokinesis-block micronucleus assay in human lymphocyte and single cell gel electrophoresis. Results The distribution of hOGG1 concentration was significantly different within all groups, P 0.05. The level of CRP was significantly changed between control and high tar group, low and high tar group and medium and high tar group, respectively, P Conclusions The increase of tar content could increase the DNA damage to a certain extent, so the intake of tar content should be monitored.

Neuron cells consist of the soma or cell body, axons, dendritic arbor with multiple branches, and dendritic spines which are the substrates for memory storage and synaptic transmission. Detriments in neuron morphology are suggested to play a key role in cognitive impairments following brain irradiation. Multiple molecular mechanisms are involved in the regulation and stability of neuron morphology, while the effects of radiation on these processes have not been studied extensively. In this report, we consider possible biological targets in neurons for energy deposition (ED) by charged particles that could lead to neuron morphology detriments, and the resulting dose and radiation quality dependence of such detriments. The track structures of heavy ions including high charge and energy (HZE) particles consists of core of high-ED events and a penumbra of sparse ED from δ-ray electrons produced in ionization of target molecules. We consider the role of track structure relative to possible targets causative in the degradation of morphology.

IF 2.047; International audience; Food contact paperboards may be a potential source of food contamination as they can release chemicals (intentionally added or not), especially recycled paperboards. In this study, we assessed the in vitro genotoxicity of food contact paperboard samples from a manufacturer, collected at the beginning and at the end of a recycling production chain. Samples were extracted in water to mimic a wet food contact. Different genotoxic endpoints were evaluated in two human hepatic cell lines (HepG2 and HepaRG) using bioassays: γH2AX and p53 activation, primary DNA damage with the comet assay and micronucleus formation. We found that the samples from the beginning and the end of the production chain induced, with the same potency, γH2AX and p53-ser15 activation and DNA damage with the comet assay. The micronucleus assay was negative with the paperboard extract from the beginning of the chain, whereas positive data were observed for the end paperboard extract. Our results indicate that samples from recycled food contact paperboard can induce in vitro genotoxic effects in our experimental conditions.

The phrase "oxidative-stress induced DNA damage" is commonly used in both the scientific literature and common media outlets, and is frequently linked to detrimental elements of aging as well as the onset of illnesses. Due to the growing focus on this topic, a clear need has emerged to develop a quantitative, low-cost methodology to allow for periodic monitoring of oxidative-stress induced DNA damage within individuals. Recent literature examining the link between oxidative stress and the onset of various cancers has made monitoring an even more pressing need. The mechanism of oxidative-stress induced DNA damage originates in chronic inflammation, which in turn activates various transcription factors and diseases that influence the onset of tumor development, chemoresistance, radioresistance, and other harmful cellular processes. While current technologies that aim to provide quantitative metrics require extremely expensive equipment and significant technical expertise, our laboratory has designed a low-cost methodology utilizing a combination of carbon nanotubes, paper electrodes, and immunochromatographic strips.

A novel device combining electrochemical and colorimetric detection is developed for the rapid measurement of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a DNA oxidative damage biomarker. The device takes advantage of the speed and low cost of the conventional strip test as well as the high reliability and accuracy of the electrochemical assay. Competitive immunoreactions were performed on the lateral flow strip, and the captured 8-OHdG on the control line was determined by chronoamperometric measurement with carbon nanotube paper as the working electrode. At the same time, the color intensity of the test line was measured by a scanner and analyzed by the ImageJ software. The device was able to detect 8-OHdG concentrations in PBS as low as 2.07 ng mL(-1) by the colorimetric method and 3.11 ng mL(-1) by the electrochemical method. Furthermore, the device was successfully utilized to detect 8-OHdG in urine with a detection limit of 5.76 ng mL(-1) (colorimetric method) and 8.85 ng mL(-1) (electrochemical method), respectively. In conclusion, the integrated device with dual detection methods can provide a rapid, visual, quantitative and feasible detection method for 8-OHdG. The integration of these two methods holds two major advantages over tests based on a single method. Firstly, it can provide double confidence on the same assay. Secondly, by involving two methods that differ in principle, the integration could potentially avoid false results coming from one method. In addition, these methods do not require expensive equipment or trained personnel, making it suitable for use as a simple, economical, portable field kit for on-site monitoring of 8-OHdG in a variety of clinical settings.

Bisphenol A (BPA) is a widely used chemical in the production of many polycarbonate plastics, epoxy resin linings for food and beverage containers and thermal papers. Oral intakes from the contaminated diets were considered as the predominant source of BPA exposure for humans. However, due to the high levels of BPA on thermal receipts and their wide applications in our daily life, the amount of BPA be transferred to the skin after holding thermal paper should not be underestimated, particularly for cashiers. To investigate the contribution of BPA exposure levels via the dermal contact route and the relationship between BPA exposure level and oxidative DNA damage, six male volunteers were recruited and required to simulate the cashiers' work and handle the thermal receipts during the study period. Triclosan (TCS, an antimicrobial compound used widely in personal health and skin care products) was applied as a reference compound. Their urinary BPA, TCS and 8-hydroxy-2′-deoxyguanosine (8-OHdG) concentrations were determined by high performance liquid chromatography/ tandem spectrometer (LC/MS/MS). The results showed that after handling the thermal receipts, the urinary BPA concentrations of volunteers increased 3 times of those before the experimental period. But TCS levels in urine kept stable. There existed a correlation between BPA exposure and 8-OHdG (R2 = 0.237, p

This article describes a paper-based low cost single cell HaloChip assay that can be used to assess drug- and radiation-induced DNA damage at point-of-care. Printing ink on paper effectively blocks fluorescence of paper materials, provides high affinity to charged polyelectrolytes, and prevents penetration of water in paper. After exposure to drug or ionizing radiation, cells are patterned on paper to create discrete and ordered single cell arrays, embedded inside an agarose gel, lysed with alkaline solution to allow damaged DNA fragments to diffuse out of nucleus cores, and form diffusing halos in the gel matrix. After staining DNA with a fluorescent dye, characteristic halos formed around cells, and the level of DNA damage can be quantified by determining sizes of halos and nucleus with an image processing program based on MATLAB. With its low fabrication cost and easy operation, this HaloChip on paper platform will be attractive to rapidly and accurately determine DNA damage for point-of-care evaluation of drug efficacy and radiation condition. Graphical Abstract Single cell HaloChip on paper.

This study presents the research on the chemical analysis and genotoxicity of 28 virgin/recycled paper products in food-contact use. In the chemical analysis, paper products were extracted by reflux with ethanol, and analyzed by gas chromatography/mass spectrometry. 4,4'-bis(dimethylamino)benzophenone (Michler's ketone: MK), 4,4'-bis(diethylamino)benzophenone (DEAB), 4-(dimethylamino)benzophenone (DMAB) and bisphenol A (BPA) were found characteristically in recycled products. Seventy-five percent of the recycled paper products contained MK (1.7-12 microg/g), 67% contained DEAB (0.64-10 micro g/g), 33% contained DMAB (0.68-0.9 microg/g) and 67% contained BPA (0.19-26 microg/g). Although, BPA was also detected in virgin paper products, the detection levels in the recycled products were ten or more times higher than those in the virgin products. The genotoxicity of paper and paperboard extracts and compounds found in them were investigated by Rec-assay and comet assay. Of the 28 products tested by Rec-assay using Bacillus subtilis, 13 possessed DNA-damaging activity. More recycled than virgin products (75% against 25%) exhibited such activity, which, of the compounds, was observed in BPA, 1,2-benzisothiazoline-3-one (BIT), 2-(thiocyanomethylthio)benzothiazole, 2,4,5,6-tetrachloro-isophthalonitrile, 2,4,6-trichlorophenol (TCP), and pentachlorophenol. The critical toxicant in one virgin paper product was concluded to be BIT. Eight samples with DNA-damaging activity were also tested by comet assay using HL-60 cells; six induced comet cells significantly (five times or higher than the control) without a decrease of viable cells. TCP, BZ, DEAB, and BIT also caused a slight increase in comet cells. In conclusion, we showed that most recycled paper products contain chemicals such as MK, DEAB, DMAB, and BPA, and possess genotoxicity. However, the levels of the chemicals in the recycled products could not explain their genotoxic effects.

Pulp and paper mill effluent compounds pollute the aquatic environment and are responsible for increased biochemical alterations and genotoxicity in aquatic organisms such as fish. Adult eels (Anguilla anguilla L) were exposed during 8, 16, 24, and 72 h to the following conditions: (1) aerated, filtered, and dechlorinated tap water (C); (2) 2.5% (v/v) sewage water previously treated with activated sludge (T); (3) bleached kraft pulp and paper mill effluent collected at the river Vouga, close to an ancient sewage outlet (Portucel), diluted in tap water [25% (E25) and 50% (E50)]; and (4) bleached kraft pulp and paper mill effluent sediment [water-soluble fraction (S)]. Liver biotransformation induced by the above conditions was measured as ethoxyresorufin-O-deethylase (EROD), cytochrome P450 (P450) (Phase I), and glutathione-S-transferase (GST) (Phase II). Genotoxicity was also determined as blood/liver DNA strand breaks and erythrocytic nuclear abnormalities (ENA) induced on European eel (A. anguilla L). Liver EROD activity was significantly increased in eels at 8 and 16 h exposure to E25, as well as at 16, 24, and 72 h exposure to E50. S exposure induced liver EROD activity only at 24h. A significant decrease in liver P450 was observed at 72 h exposure to T, whereas a significant P450 increase at 16 h was followed by a significant decrease at 24h exposure to E25. Another P450 significant increase was noticed at 72 h exposure to S. Liver GST activity (Phase II) demonstrated a significant increase at 72 h exposure to E50 and to S. A significant decrease in blood DNA integrity was observed at 72 h exposure to T and at 24 and 72 h to S. Blood DNA integrity significantly decreased at 16 and 24 h exposure to E25, as well as at 8, 16, and 24 h exposure to E50. Liver DNA integrity significantly decreased at 72 h exposure to T and at 16 h exposure to S. Moreover, liver DNA integrity was significantly decreased at 24h exposure to E25 and E50, and 72 h to E50. A. anguilla L. increased ENA frequency was detected in T at 16, 24, and 72 h, whereas in E25 and S it was observed at 8, 16, and 24 h. Furthermore, E50 ENA frequency increased at 24 h exposure.

Lake Baikal, a unique habitat for a great number of endemic species, is the largest freshwater reservoir in the world which is still largely unaffected by anthropogenic pollution, except for some shore regions with industrial activity. The expressions of a biomarker of exposure (heat shock protein Hsp70) and a biomarker of effect (DNA single-strand breaks) were measured for the first time in endemic Baikalian sponge species (Baikalospongia intermedia, Lubomirskia fusifera, and Lubomirskia abietina). Tissue cubes of B. intermedia and dissociated cells of L. fusifera and L. abietina reacted to temperature stress (10–16 °C above ambient temperature) with a time-dependent increase in expression of Hsp70. In B. intermedia, the effects of model pollutants (lead, copper, and zinc, and the organochlorines tetrachloroguaiacol, TCG, and pentachlorophenol, PCP) and of the wastewater from the final refinement and aeration reservoirs of the Baikalsk Pulp and Paper Plant (BPPP), located at the shore of the southern basin of Lake Baikal, on the expression of Hsp70 and the extent of DNA damage were investigated. It was found that lead and zinc but not copper cause a strong induction of Hsp70 in this sponge, while the frequency of DNA single-strand breaks increased after exposure to all these heavy metals tested. Induction of DNA single-strand breaks was also observed after exposure to TCG and PCP, but these compounds did not (consistently) enhance Hsp70 expression. Wastewater taken from the final water aeration pond of BPPP caused a concentration-dependent increase in Hsp70 expression in B. intermedia. However, there was no difference in the basal levels of Hsp70 between sponges collected in the shallow water at an unpolluted site near Baikalsk City and at a polluted site where the wastewaters of BPPP are discharged into the lake. There was also no clear difference in the wastewater concentration-dependent induction of Hsp70 expression between sponges collected at these sites, indicating no adaptation to continuous stress exposure.

Generally, handmade paper industries are considered as eco-friendly industries. These industries are known to use vegetable dyes which are thought to be safe and non-toxic. However, cardboard industries are considered as pollution-causing industries. The present study focuses on the genotoxic assessment of handmade paper and cardboard industry’s effluent by Ames test using Salmonella typhimurium TA 98 and TA 100 strains. On mutagenicity analysis, effluents of both industries were found to be mutagenic with either one strain of Salmonella typhimurium or with both. Besides this, no significant difference was observed in effluent of both small-scale and large-scale handmade paper industries. Moreover, mutagenic compounds reach the nearby water body i.e. Amani Shah Drainage through connecting drain. Discharging of untreated effluent not only deteriorates the water quality but also reaches the food chain when used for irrigating nearby fields. Workers of these industries may suffer various health hazards when they are exposed to mutagenic effluent without having any information about it. Hence, discharging of effluents should thus be restricted or the workers while handling mutagenic substances should at least take proper precautions.

Fish populations residing in a river receiving bleached kraft mill effluents (BKME) and in an uncontaminated river were investigated to evaluate causal relationships between exposure to BKME and various indicators of fish health. The Index of Biotic Integrity demonstrated that species richness and composition were much lower in the contaminated river with an obvious imbalance in the trophic structure of the fish community. Biomolecular and biochemical responses such as DNA damage and elevated activity of detoxification enzymes indicated that fish in the contaminated river had been exposed to toxicants. The status of various condition indices such as the liver and visceral somatic indices suggested metabolic and nutritional imbalances in sunfish as a result of exposure to pulp mill effluents. Fish populations in the contaminated river also demonstrated an abnormal size distribution and age structure. Female redbreast sunfish from the BKME-impacted river contained a large number of atretic oocytes and had lower serum levels of estradiol than fish from the reference site. These observations plus data from previous developmental toxicity studies suggest that the primary mechanism by which BKME may affect fish populations in this river is through reproductive dysfunction and recruitment failure. Decreased recruitment may have caused a reduction in population size and resulted in decreased competition and increased resource availability. With increased food and habitat availability, more energy may have been available for growth and lipid storage of survivors in the contaminated river.

In order to identify potential genotoxicant(s) in recycled paperboard, samples were fractionated using multiple liquid/liquid extraction, and gel permeation chromatography, and analysed by gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry. The rec-assay was used as an indicator of genotoxicity. Genotoxicants in the recycled paperboard were identified as dehydroabietic acid (DHA) and abietic acid (AA). DHA and AA were detected in two out of five virgin products, and in all seven recycled products for food-contact use. Total amounts of DHA and AA were 240 and 990 microg/g in the virgin products and 200-990 microg/g in the recycled products. A good correlation was observed in the total amount of DHA and AA content determined in paper products and DNA-damaging activity. Moreover, genotoxic effects in paper products showed a good match with standard compounds, indicating that the genotoxic effects of these paper products was mostly attributable to DHA and AA.