Mutagenicity (micronucleus test in Vicia faba root tips), polycyclic aromatic hydrocarbons and heavy metal content of sediments collected in Tiber river and its tributaries within the urban area of Rome

Accumulation of polycyclic aromatic hydrocarbons (PAHs) in surface sediment residues of Mahanadi River Estuary: Abundance, source, and risk assessment

In this study, we examined the distribution of polycyclic aromatic hydrocarbons (PAHs) in sediments from the Mahanadi River Estuary (MRE), identified sources, and evaluated the ecological toxicity. The PAHs distributions in MRE ranged from 13.1 to 685.4 ng g^-1 (dry weight), with a mean value of 192.91 ± 177.56 ng g^-1 (dry weight). Sediments at sites S11, S8, and S13 have the highest 3-rings, 4-rings, and 5-rings PAHs, respectively. In MRE, pyrene has a significantly higher concentration with a mean value of 30.51 ng g^-1, followed by Fluoranthene (86.2 ng g^-1), Chrysene (67.4 ng g^-1), and Benzo(k)fluoranthene (54.2 ng g^-1). Site S8 had a higher total PAH concentration than sites S11, S13, and S1. The diagnostic and principal component analysis suggests that PAHs originated from petroleum, oil, biomass, and coal combustion. Higher toxic and mutagenic equivalent quotients indicate potential aquatic toxicity and a need for continuous monitoring of MRE for PAHs pollution.

Estimation of Polycyclic Aromatic Hydrocarbons Pollution in Mediterranean Sea from Volturno River, Southern Italy: Distribution, Risk Assessment and Loads

This study reports the data on the contamination caused by polycyclic aromatic hydrocarbons (PAHs) drained from the Volturno River. The seasonal and spatial distribution of PAHs in water and sediment samples was assessed. The 16 PAHs were determined in the water dissolved phase (DP), suspended particulate matter (SPM), and sediments. A multidimensional statistical approach was used to identify three pollution composite indicators. Contaminant discharges of PAHs into the sea were calculated in about 3158.2 kg/year. Total concentrations of PAHs varied in ranges 434.8 to 872.1 ng g⁻¹ and 256.7 to 1686.3 ng L⁻¹ in sediment samples and in water (DP + SPM), respectively. The statistical results indicated that the PAHs mainly had a pyrolytic source. Considering the sediment quality guidelines (SQGs), the water environmental quality standards (USEPA EQS), and risk quotient (RQ), the Volturno River would be considered as an area in which the environmental integrity is possibly at risk.

Chemical mixtures and fluorescence in situ hybridization analysis of natural microbial community in the Tiber river

The Water Framework Directive (WFD) regulates freshwater and coastal water quality assessment in Europe. Chemical and ecological water quality status is based on measurements of chemical pollutants in water and biota together with other indicators such as temperature, nutrients, species compositions (phytoplankton, microalgae, benthos and fish) and hydromorphological conditions. However, in the current strategy a link between the chemical and the ecological status is missing. In the present WFD, no microbiological indicators are foreseen for integrating the different anthropogenic pressures, including mixtures of chemicals, nutrients and temperature changes, to provide a holistic view of the freshwater ecosystem water quality. The main aim of this work was to evaluate if natural microbial populations can be valuable indicators of multiple stressors (e.g. chemical pollutants, temperature, nutrients etc.) to guide preventive and remediation actions by water authorities. A preliminary survey was conducted to identify four sites reflecting a contamination gradient from the source to the mouth of a river suitable to the objectives of the European Marie Curie project, MicroCoKit. The River Tiber (Italy) was selected as a pilot case study to investigate the correlation between bacteria taxa and the chemical status of the river. The main physicochemical parameters, inorganic elements, organic pollutants and natural microbial community composition were assessed at four selected sites corresponding to pristine, agricultural, industrial and urban areas for three consecutive years. The overall chemical results indicated a correspondence between different groups of contaminants and the main contamination sources at the selected sampling points. Phylogenetic analysis of the microbial community analyzed by Fluorescence In Situ Hybridization method (FISH) revealed differences among the four sampling sites which could reflect an adaptive bacterial response to the different anthropogenic pressures.

Micro-pollutants in sediment samples in the middle Danube region, Serbia: occurrence and risk assessment

This is the first comprehensive study on the occurrence of 940 semi-volatile organic compounds including sterols, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pesticides, plasticizers, and other emerging compounds in 10 river and canal sediments collected in northern Serbia. For quantification of investigated compounds GC-MS-MS (selected reaction monitoring) and GC-MS (using both selected ion monitoring and total ion monitoring) methods were used. The number of detected compounds was in the range of 85-117, while the sum of the concentrations varied from 959 μg/kg dry-wt to 84,445 μg/kg dry-wt. Sterols were quantified with high frequency in nearly 100% of investigated samples suggesting that the studied rivers and canals have been contaminated by sewage. Regarding persistent organic compounds, p,p'-DDE, p,p'-DDD, and o,p'-DDT were the dominant members of organochlorine pesticides (OCPs). The concentration range of 11 quantified pesticides of 452 analyzed was from 0.564 to 61.6 μg/kg dry-wt, while the concentration range of 47 quantified PCBs of 90 analyzed was from 0.928 to 32.1 μg/kg dry-wt. OCPs (DDE, DDD, and γ-HCH) and several PAHs (fluoranthene, pyrene, phenanthrene, chrysene, benzo(a)anthracene, benzo(a)pyrene) exceeded the maximum values of the sediment quality guidelines. Contents of domestic compounds comprise a large proportion of the total contaminant concentration. Overall, the study reveals that river sediments in Vojvodina Province were moderately polluted mainly by domestic wastewater. The toxic equivalent quantity (TEQ) relative to benzo(a)pyrene and 2,3,7,8-tetrachlorodibenzodioxin for seven carcinogenic PAHs and six quantified dioxin-like PCBs ranged from 3.59 to 103 μg TEQ/kg and from 0.001 × 10^-3 to 2.10 × 10^-3 μg TEQ/kg, respectively, and were in the range or lower than the literature published data.

Toxicity and genotoxicity assessment in sediments from the Matanza-Riachuelo river basin (Argentina) under the influence of heavy metals and organic contaminants

The aim of this study was to investigate the parameters of chemical extraction associated with the detection of toxicity and genotoxicity in sediment sample extracts. Quantitative analysis of metals and polycyclic aromatic hydrocarbons (PAHs), together with a battery of four bioassays, was performed in order to evaluate the extraction efficiency of inorganic and organic toxicants. The extracts were carried out using two inorganic solvents, two organic solvents and two extraction methodologies, making a total of five extracts. Two toxicity tests, the algal growth inhibition of Pseudokirchneriella subcapitata and the root elongation inhibition of Lactuca sativa, and two genotoxicity tests, the analysis of revertants of Salmonella typhimurium and the analysis of micronuclei and chromosomal aberrations in Allium cepa, were performed. According to the chemical analysis, the acidic solution extracted more heavy metal concentrations than distilled water, and dichloromethane extracted more but fewer concentrations of PAH compounds than methanol. Shaker extracts with distilled water were non-toxic to P. subcapitata, but were toxic to L. sativa. The acidic extracts were more toxic to P. subcapitata than to L. sativa. The methanolic organic extracts were more toxic to the alga than those obtained with dichloromethane. None of these extracts resulted toxic to L. sativa. Mutagenic effects were only detected in the organic dichloromethane extracts in the presence of metabolic activation. All the inorganic and organic extracts were genotoxic to A. cepa. This study showed that the implementation of different extraction methods together with a battery of bioassays could be suitable tools for detecting toxicity and genotoxicity in sediment samples.

Estimation of heavy metal loads from Tiber River to the Tyrrhenian Sea and environmental quality assessment

In order to evaluate the heavy metal pollution in the Tiber River and its environmental impact on the Tyrrhenian Sea (Central Mediterranean Sea), eight heavy metals (As, Hg, Cd, Cr, Cu, Ni, Pb and Zn) were determined in the water dissolved phase, suspended particulate matter and sediment samples collected from 21 sites in different seasons. Total heavy metal concentrations ranged from 34.88 to 4201.23 μg L^-1 in water (as the sum of the water dissolved phase and suspended particulate matter) and from 42.81 to 1686.84 mg kg^-1 in sediment samples. The total selected heavy metal load contribution into the sea is calculated in about 21,257.85 kg year^-1, showing that this River should account as one of the main contribution sources of heavy metals in the Mediterranean Sea. In relation to the ecological assessment, the Tiber River and Estuary would be considered as an area in which the ecological integrity is possibly at risk.

Distribution, sources and ecological risk assessment of polycyclic aromatic hydrocarbons in water and sediments from Tiber River and estuary, Italy

The concentration, source and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in the Tiber River and its environmental impact on the Tyrrhenian Sea (Central Mediterranean Sea) were estimated. The 16 priority PAHs were determined in the water dissolved phase (DP), suspended particulate matter (SPM) and sediments collected from 21 sites in four different seasons. Total concentrations of PAHs ranged from 10.3 to 951.6ngL(-1) and from 36.2 to 545.6ngg(-1) in water (sum of DP and SPM) and in sediment samples, respectively. The compositions of PAHs showed that 2- to 4-ring PAHs were abundant in DP, 4- to 6-ring PAHs were predominant in SPM samples, and 4- to 5-ring PAHs were abundant in sediments. The diagnostic ratio analysis indicated that the PAHs mainly had a pyrolytic source. The toxic equivalent concentration of carcinogenic PAHs was 45.3ngTEQg(-1), suggesting low carcinogenic risk for Tiber River. Total PAHs loads into the sea were calculated in about 3161.7kgyear(-1) showing that this river is one of the main contribution sources of these contaminants to the Tyrrhenian Sea.

Drinking water: a risk factor for high incidence of esophageal cancer in Anyang, China

Anyang is known to be a high-incidence area of esophageal cancer (EC) in China. Among a long list of risk factors, the quality of drinking water was evaluated. We have selected 3806 individuals and collected 550 drinking water samples correspondent with this not-matched case-control survey. There are 531 EC patients included based on Population Cancer Registry from 92 townships, of which 3275 controls with long-lived aged over 90 years and free from EC are used as controls in the same regions. Our result suggests that the quality of drinking water is a highly associated risk factor for EC. The residential ecological environment and the quality of water resource positively link with each other. The analysis of water samples also demonstrated that the concentrations of methyl ethylamine, morpholine, N-methylbenzylamine, nitrate and chloride in water from springs and rivers are higher than those in well and tap water (P = 0.001). Micronuclei formation tests show that well water and tap water in these regions have no mutagenicity.

Characterizations of bio-accumulations, subcellular distribution and chemical forms of cesium in Brassica juncea, and Vicia faba

We aim to investigate the tolerance and enrichment mechanism of cesium (Cs) in hyperaccumulation plants. In this study, Brassica juncea and Vicia faba were subjected to varying doses of Cs for 21 days to investigate the differences in bio-accumulations, subcellular distribution and chemical forms of Cs in two cultivars by differential centrifugation, and extraction of Cs in different chemical forms, respectively. The results showed that 49.87%-61.08% of the Cs were in the leaf of B. juncea, while in V. faba, 1.58%-79.29% of the Cs was in the root. The translocation factor (TF) arrived 2.79 to 3.71 in B. juncea, while it only reached 0.26 to 0.62 in V. faba. Cs subcellular distribution of the two plants was in sequence as follows: soluble fraction > cell wall >> organelles. Cs was more easily distributed to metal-sensitive fractions of V. faba. The inorganic Cs (F-ethanol), and water-soluble Cs (F-dH2O) are the main existing types of Cs in the two plants. In B. juncea, the relative content of inorganic Cs, and organic acids/CsH2PO4 (F-dH2O) were higher than that of V. faba in the stem. This suggests that Cs may induce related transporter gene expression (such as phosphate transporter, organic cation, high affinity nitrate transporter, amino acid permease, etc.) to help the transport of Cs between root to shoot.

Evaluation of drinking water treatment combined filter backwash water recycling technology based on comet and micronucleus assay

Based on the fact that recycling of combined filter backwash water (CFBW) directly to drinking water treatment plants (WTP) is considered to be a feasible method to enhance pollutant removal efficiency, we were motivated to evaluate the genotoxicity of water samples from two pilot-scale drinking water treatment systems, one with recycling of combined backwash water, the other one with a conventional process. An integrated approach of the comet and micronucleus (MN) assays was used with zebrafish (Danio rerio) to investigate the water genotoxicity in this study. The total organic carbon (TOC), dissolved organic carbon (DOC), and trihalomethane formation potential (THMFP), of the recycling process were lower than that of the conventional process. All the results showed that there was no statistically significant difference (P>0.05) between the conventional and recycling processes, and indicated that the genotoxicity of water samples from the recycling process did not accumulate in 15 day continuous recycling trial. It was worth noting that there was correlation between the concentrations of TOC, DOC, UV254, and THMFPs in water and the DNA damage score, with corresponding R(2) values of 0.68, 0.63, 0.28, and 0.64. Nevertheless, both DNA strand breaks and MN frequency of all water samples after disinfection were higher than that of water samples from the two treatment units, which meant that the disinfection by-products (DBPs) formed by disinfection could increase the DNA damage. Both the comet and MN tests suggest that the recycling process did not increase the genotoxicity risk, compared to the traditional process.

Vicia faba bioassay for environmental toxicity monitoring: A review

Higher plants are recognized as excellent genetic models to detect cytogenetic and mutagenic agents and are frequently used in environmental monitoring studies. Vicia faba (V. faba) bioassay have been used to study DNA damages i.e., chromosomal and nuclear aberrations induced by metallic compounds, pesticides, complex mixtures, petroleum derivates, toxins, nanoparticles and industrial effluents. The main advantages of using V. faba is its availability round the year, economical to use, easy to grow and handle; its use does not require sterile conditions, rate of cell division is fast, chromosomes are easy to score, less expensive and more sensitive as compared to other short-term tests that require pre-preparations. The V. faba test offers evaluation of different endpoints and tested agents can be classified as cytotoxic/genotoxic/mutagenic. This test also provides understanding about mechanism of action, whether the tested agent is clastogenic or aneugenic in nature. In view of advantages offered by V. faba test system, it is used extensively to assess toxic agents and has been emerged as an important bioassay for ecotoxicological studies. Based on the applications of V. faba test to assess the environmental quality, this article offers an overview of this test system and its efficiency in assessing the cytogenetic and mutagenic agents in different classes of the environmental concerns.

Soil genotoxicity induced by successive applications of chlorothalonil under greenhouse conditions

Greenhouse production of vegetables has been developed rapidly in China. High temperature and humidity inside the greenhouse make this environment more suitable for fast reproduction of fungal diseases. Fungicides are among the chemicals used extensively in the greenhouse to prevent crops from invasive infections by phytopathogens; however, little is known about the accumulation of fungicides in soil and their effect on soil quality under greenhouse conditions. In the present study, the accumulation of the fungicide chlorothalonil (CT) and its toxic metabolite hydroxy-chlorothalonil (HCT) in soil as well as their related soil genotoxicity under greenhouse conditions was investigated. The results indicated that both CT and HCT accumulated in soil with repeated applications of CT, and the accumulation level was strongly correlated to application dosage and its frequency. In addition, soil genotoxicity, which was measured by Vicia faba, also increased with the accumulation of CT and HCT, and the main contributor to this phenomenon was CT rather than HCT. The data demonstrated that successive applications of fungicides may result in their accumulation in soil and thus a decline in soil quality.

Genotoxicity of the sediments collected from Pearl River in China and their polycyclic aromatic hydrocarbons (PAHs) and heavy metals

The accelerated industrialization and urbanization in the last three decades around the Pearl River Delta within Guangdong Province in China have led to serious concerns about the impacts on the aquatic environment. In the present study, the genotoxicity of the sediments collected from the Pearl River was evaluated by micronucleus (MN) assay with Vicia faba root tip cells, and the 16 EPA priority polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs, including Cr, Cu, As, Se, Cd, Hg, and Pb) in the sediments were determined respectively by GC-MS, inductively coupled plasma mass spectrometry, and inductively coupled plasma atomic emission spectrometry. The results showed that there were significant increases of MN frequencies observed in the sediment-exposed groups, compared with the negative group (P < 0.05, P < 0.01), indicating that the sediments clearly had genotoxicity to the V. faba root cells. The total concentrations of the priority PAHs (250-13,656 ng g(-1), dry weight) and HMs (As, 22,770-36,639 μg kg(-1); Cr, 39,333-133,343 μg kg(-1); Cu, 36,145-159,270 μg kg(-1); Pb, 51,210-166,642 μg kg(-1); Cd, 475.4-1,818.9 μg kg(-1); Hg, 59.9-460.8 μg kg(-1); and Se, 331.7-1,250.4 μg kg(-1), dry weight) were close to those obtained from other urbanized and industrialized areas, which have been considered moderately polluted. There was a clear positive correlation between MN potency and the molar concentrations of Hg and Pb in the sediments (Hg, r = 0.94; Pb, r = 0.91), suggesting that Hg and Pb were the most important factors that posed the sediments higher genotoxicity to V. faba root cells. Our results suggested that both biological and chemical approaches are necessary to be included in a battery of tests to assess the eco-environmental risks of sediments.

Distribution, source identification, and historical trends of organic micropollutants in coastal sediment in Jakarta Bay, Indonesia

We determined concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), linear alkylbenzenes (LABs), and hopanes in coastal sediments collected from Jakarta Bay and Tokyo Bay. PAH concentrations in sediments from Jakarta Bay (257-1511 ng/g-dry) were lower than or comparable to those from Tokyo Bay (1372-1615 ng/g-dry). Ratios of alkyl-PAHs to parent PAHs showed a greater contribution of petrogenic inputs in Jakarta Bay than in Tokyo Bay. This difference is consistent with the higher ratio of hopanes to PAHs in Jakarta Bay. LAB concentrations in Jakarta Bay (geometric mean, 1400 ng/g-dry) were higher than those in Tokyo Bay (661 ng/g-dry). The internal to external (I/E) ratios of LABs in Jakarta Bay (0.92-2.88) were lower than those in Tokyo Bay (2.8-4.8), indicating that Jakarta Bay receives untreated or poorly treated sewage. Significant amounts of tetrapropylene-based alkylbenzenes were detected in several locations in Jakarta Bay, suggesting current usage of the non-degradable surfactants alkylbenzene sulfonates that are banned in many countries. The PCB concentration in Jakarta Bay was 1 order of magnitude lower than in Tokyo Bay, suggesting minimal usage of PCBs in industrial or commercial products in Jakarta. Analyses of a sediment core indicate increasing inputs of PAHs, hopanes, and LABs into Jakarta Bay during recent decades.

Polycyclic aromatic hydrocarbons loads into the Mediterranean Sea: estimate of Sarno River inputs

The polycyclic aromatic hydrocarbons (PAHs) pollution in the Sarno River and its environmental impact on the Gulf of Naples (Tyrrhenian Sea, Central Mediterranean Sea) were estimated. The 16 PAHs identified by the USEPA as priority pollutants and perylene were determined in the water dissolved phase (DP), suspended particulate matter (SPM) and sediments. Total PAHs concentrations ranged from 23.1 to 2670.4 ng L(-1) in water (sum of DP and SPM) and from 5.3 to 678.6 ng g(-1) in sediment samples. Source analysis revealed that PAHs mainly came from combustion process. Contaminant discharges of PAHs into the sea were calculated in about 8530 gd(-1) showing that this river should account as one of the main contribution sources of PAHs to the Tyrrhenian Sea.

Ground and surface water for drinking: a laboratory study on genotoxicity using plant tests

ABSTRACT

Surface waters are increasingly utilized for drinking water because groundwater sources are often polluted. Several monitoring studies have detected the presence of mutagenicity in drinking water, especially from surface sources due to the reaction of natural organic matter with disinfectant. The study aimed to investigate the genotoxic potential of the products of reaction between humic substances, which are naturally present in surface water, and three disinfectants: chlorine dioxide, sodium hypochlorite and peracetic acid. Commercial humic acids dissolved in distilled water at different total organic carbon (TOC) concentrations were studied in order to simulate natural conditions of both ground water (TOC=2.5 mg/L) and surface water (TOC=7.5 mg/L). These solutions were treated with the biocides at a 1:1 molar ratio of C:disinfectant and tested for genotoxicity using the anaphase chromosomal aberration and micronucleus tests in Allium cepa, and the Vicia faba and Tradescantia micronucleus tests. The tests were carried out after different times and with different modes of exposure, and at 1:1 and 1:10 dilutions of disinfected and undisinfected humic acid solutions. A genotoxic effect was found for sodium hypochlorite in all plant tests, at both TOCs considered, while chlorine dioxide gave positive results only with the A.cepa tests. Some positive effects were also detected for PAA (A.cepa and Tradescantia). No relevant differences were found in samples with different TOC values. The significant increase in all genotoxicity end-points induced by all tested disinfectants indicates that a genotoxic potential is exerted even in the presence of organic substances at similar concentrations to those frequently present in drinking water.

Occurrence of priority hazardous PAHs in water, suspended particulate matter, sediment and common eels (Anguilla anguilla) in the urban stretch of the River Tiber (Italy)

This study investigated the occurrence of polycyclic aromatic hydrocarbons (PAHs) in water, suspended particulate matter (SPM), bed sediment and common eels (Anguilla anguilla) in the urban stretch of the River Tiber (Italy). The selected PAHs, fluoranthene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, benzo(g,h,i)perylene, indeno(1,2,3-cd)pyrene, belong to the EC priority list of dangerous substances. SPM was found to be the most polluted compartment, with values ranging from 1663.1 to 15472.9 ngg(-1) (Σ(6)PAHs), followed by sediment samples, from 157.8 to 271.6 ngg(-1) and by aqueous samples, from 23.9 to 72.0 ngL(-1). The distribution coefficient (K(d)) showed a good correlation with particle organic carbon (OC) content, while K(oc) values experimentally measured for sediment/SPM deviated from those predicted by K(ow), implying that for very hydrophobic compounds, K(ow) alone may not be an appropriate descriptor of all the thermodynamic forces involved in their sorption to aquatic particles. Some selected PAH ratios indicated that PAHs in the River Tiber come mainly from pyrolitic sources and vehicular traffic. Concentrations of individual PAHs in muscles of common eels varied from 0.8 to 7.0 ngg(-1) wet wt. and the calculated toxicity equivalent concentration (TEQ, 1.8 ngg(-1) wet wt.) of total PAHs fell below the recommended screening value (SV) in US EPA guidelines, suggesting no concern for human consumption.

The effect of cyanide compounds, fluorides, aluminum, and inorganic oxides present in spent pot liner on germination and root tip cells of Lactuca sativa

SPL (spent pot liner) is a solid waste produced by the aluminum industry. This waste has a highly variable composition, consisting of cyanides, fluorides, organics, and metals. The aim of this work was to study the effect of SPL on root tips of Lactuca sativa using current plant bioassays. We observed a decrease in the germination rate with increasing concentrations of SPL. In addition, SPL was found to reduce root growth, which is correlated with a decrease in the mitotic index. Nevertheless, we noticed a significant enhancement in the percentage of stickiness, c-metaphase, anaphase bridges, and laggard chromosomes in dividing cells and also an increase in the number of cells with condensed nuclei. Moreover, SPL was found to alter the root tip surface, resulting in a reduction in the amount of root hair. These results demonstrate that SPL is a toxic agent that leads to cell damage and disturbance.

New direct contact approach to evaluate soil genotoxicity using the Vicia faba micronucleus test

A method to assess micronucleus (MN) induction in Vicia faba roots by direct contact exposure to a solid matrix was developed. The procedure comprised a 5-d germination period, as in the well-known method using aqueous extracts. However, the seeds were here sown directly into the test soil whereas a culture period is necessary before exposing seedlings to a liquid medium. One soil under forest and two contaminated soils from areas affected by industrial installations and a coke works were used. Three durations of direct exposure were tested: 2, 5 and 7 d. The optimal duration was evaluated at 2 d to observe maximal MN induction without observing toxicity symptoms. The methodology using aqueous extracts was applied to the same three soils: MN frequency was higher than in the direct contact assay but the ratios of MN frequencies from tested soils in comparison to the negative control were lower. However, for each soil, both the direct contact method and the aqueous extract exposure led to the same risk assessment diagnosis. The evaluation of a concentration range of a polycyclic aromatic hydrocarbons (PAH)-contaminated soil showed a dose-dependent MN frequency when the seeds were allowed to germinate before sowing in the soil: the soil genotoxicity was the highest at intermediate doses. The direct contact method was found to be rapid, sensitive and well suited to the evaluation of soil quality.

Mycorrhization alleviates benzo[a]pyrene-induced oxidative stress in an in vitro chicory root model

Among chemicals that are widely spread both in terrestrial and aquatic ecosystems, benzo[a]pyrene is a major source of concern. However, little is known about its adverse effects on plants, as well as about the role of mycorrhization in protection of plant grown in benzo[a]pyrene-polluted conditions. Hence, to contribute to a better understanding of the adverse effects of polycyclic aromatic hydrocarbons on the partners of mycorrhizal symbiotic association, benzo[a]pyrene-induced oxidative stress was studied in transformed Cichorium intybus roots grown in vitro and colonized or not by Glomus intraradices. The arbuscular mycorrhizal fungus development (colonization, extraradical hyphae length, and spore formation) was significantly reduced in response to increasing concentrations of benzo[a]pyrene (35-280 microM). The higher length of arbuscular mycorrhizal roots, compared to non-arbuscular mycorrhizal roots following benzo[a]pyrene exposure, pointed out a lower toxicity of benzo[a]pyrene in arbuscular mycorrhizal roots, thereby suggesting protection of the roots by mycorrhization. Accordingly, in benzo[a]pyrene-exposed arbuscular mycorrhizal roots, statistically significant decreases were observed in malondialdehyde concentration and 8-hydroxy-2'-desoxyguanosine formation. The higher superoxide dismutase activity detected in mycorrhizal chicory roots could explain the benzo[a]pyrene tolerance of the colonized roots. Taken together, these results support an essential role of mycorrhizal fungi in protecting plants submitted to polycyclic aromatic hydrocarbon, notably by reducing polycyclic aromatic hydrocarbon-induced oxidative stress damage.

River water genotoxicity evaluation using micronucleus assay in fish erythrocytes

The quality of Caí river water (Rio Grande do Sul State) in an area under the influence of a petrochemical complex was studied using the micronucleus assay in erythrocytes from peripheral blood of the fathead minnow Pimephales promelas. This cytogenetic in vivo assay was performed to evaluate the effects of petrochemical effluents on the stream. Organisms were exposed to samples collected at four sites, during an 11-month period. Three different exposure periods were used (7, 14, and 21 days) to evaluate their influence in genotoxic detection. The 14-day exposure period was most effective in detecting genotoxicity in samples from this area. The presence of substances with clastogenic and/or aneugenic potential could be detected at the different sites analyzed. This in vivo assay allowed the detection of genotoxicity in the area studied, indicating the potential for environmental genotoxicity monitoring.

Genotoxicity assessment of soils from wastewater irrigation areas and bioremediation sites using the Vicia faba root tip micronucleus assay

Genotoxicity potential of soils taken from wastewater irrigation areas and bioremediation sites was assessed using the Vicia faba root tip micronucleus assay. Twenty five soils were tested, of which 8 were uncontaminated soils and taken as the control to examine the influence of soil properties; 6 soils were obtained from paddy rice fields with a history of long-term wastewater irrigation; 6 soils were obtained from bioremediation sites to examine effects of bioremediation; and 5 PAH-contaminated soils were used to examine methodological effects between direct soil exposure and exposure to aqueous soil extracts on micronuclei (MN) frequency ( per thousand) in the V. faba root tips. Results indicate that soil properties had no significant influences on MN frequencies (p > 0.05) when soil pH varied between 3.4 to 7.6 and organic carbon between 0.4% and 18.6%. The MN frequency measured in these control soils ranged from 1.6 per thousand to 5.8 per thousand. MN frequencies in soils from wastewater irrigation areas showed 2- to 48-fold increase as compared with the control. Soils from bioremediation sites showed a mixed picture: MN frequencies in some soils decreased after bioremediation, possibly due to detoxification; whereas in other cases remediated soils induced higher MN frequencies, suggesting that genotoxic substances might be produced during bioremediation. Exposure to aqueous soil extracts gave a higher MN frequency than direct exposure in 3 soils. However, the opposite was observed in the other two soils, suggesting that both exposure routes should be tested in case of negative results from one route. Data obtained from this study indicate that the MN assay is a sensitive assay suitable for evaluating genotoxicity of soils.

Use of plant genotoxicity bioassay for the evaluation of efficiency of algal biofilters in bioremediation of toxic industrial effluent

The toxicity and efficacy of an algal-based bioremediation technology were assessed through bioassays for ecological risk of contaminated industrial effluents. The algal bioremoval of heavy metals was evaluated using an in vitro approach. Phytogenotoxicity tests were conducted with Allium cepa and Vicia faba plants to evaluate the genotoxicity of the industrial effluents before and after treatment with different kinds of algal biofilters (BF). Root cells were exposed for 24 h to different dilutions of both raw and treated effluent of a chemical fertilizer factory. Three cytogenetic endpoints were used to assess the mutagenic potencies of the industrial effluent: mitotic inhibition, mitotic chromosome aberrations, and nuclear irregularities in interphase cells. Before algal treatment, the industrial effluent caused strong genotoxic effects represented by severe inhibition in mitotic activity of meristematic cells and high frequency of both chromosome and nucleus abnormalities. After algal treatment, the cytotoxic effects of 30% and 60% concentrations of the treated effluent were comparable to those of 5% and 10% concentrations before treatment, respectively, and the frequency of both chromosome and nuclear abnormalities declined by approximately 50%. Statistical analysis of the data indicates a significant reduction in genotoxicity associated with a remarkable reduction in heavy metal concentrations after bioremediation by algal BF. The Allium and Vicia genotoxicity approach was effective in monitoring bioremediated effluent for toxicity.

Molecular evidence for benzo[a]pyrene and naphthalene genotoxicity in Trifolium repens L

Polycyclic aromatic hydrocarbons (PAHs) are among the most dangerous environmental contaminants due to their toxic, carcinogenic and mutagenic effects. Although there are many data in literature that detail the effects of PAHs on animals, little is known about their action on higher plants which are often used as bioindicators. The aim of the present study was to evaluate the genotoxicity of two different PAHs, benzo[a]pyrene (BaP) and naphthalene (Naph), on Trifolium repens L. Clover plants were exposed to soil which had been artificially contaminated with three concentrations of BaP (5, 10 and 20 microg g-1) or Naph (25, 50 and 100 microg g-1). After 15 days, changes in the DNA content and sequence of roots and shoots were evaluated by flow cytometry (FCM) and amplified fragment length polymorphism (AFLP). Root and shoot dry weight were also determined to assess plant growth. Results showed that BaP and Naph were both genotoxic for white clover, inducing significant changes in root and shoot DNA sequence. Damage was more severe in the root than in the shoot suggesting that the translocation of these compounds and their genotoxic metabolites was limited. Ploidy alterations were not detected and the extent of damage caused by all the tested PAH concentrations was not sufficient to affect plant development.

The piscine micronucleus test to assess the impact of pollution on the Japaratuba river in Brazil

In situ investigations of the effects of mutagenic pollutants (environmental monitoring) have increasingly used bioindicators, and fish often have been used in these studies as sentinel organisms. In the present study, we have used the piscine micronucleus test (MNT) as an in situ biological indicator of chemical contamination in two fresh water fish species (Astyanax bimaculatus and Hoplias malabaricus). The fish were collected from two sites (Sites 1 and 2) in the Japaratuba River (Sergipe, Brazil), in an area impacted by a petrochemical industrial complex which indirectly contributes treated effluent (produced water) to the river. Responses in fish from these sites were compared to fish from a clean reference site (Jacarecica River - Sergipe, Brazil). The results indicated an enhanced frequency of micronuclei (MN) in peripheral red blood cells of A. bimaculatus collected at Sites 1 and 2 when compared to their respective negative control (A. bimaculatus collected from the Jacarecica River). H. malabaricus collected at Sites 1 and 2 did not have a significant increase in MN. The results of this study indicate that the piscine MNT is a useful in vivo technique for the detection of chemical contaminants in the aquatic environment and that the assay shows potential for in situ monitoring of water quality. Nevertheless, the results also demonstrated differential sensitivity of A. bimaculatus and H. malabaricus to the induction of MN.

Genotoxicity of drinking water disinfectants in plant bioassays

The genotoxicity of two widely used drinking water disinfectants, sodium hypochlorite (NaClO) and chlorine dioxide (ClO(2)), and a new disinfectant, peracetic acid (PAA, CH(3)-CO-COOH), was evaluated in three short-term plant tests: (1) induction of anaphase chromosome aberrations in the root cells of Allium cepa, (2) micronucleus induction in the root cells of Vicia faba, and (3) micronucleus induction in Tradescantia pollen cells. The study was carried out in the laboratory by directly exposing the plants to several concentrations of the disinfectants in redistilled water at unadjusted (acid) and adjusted (neutral) pHs. Both 0.1 and 0.2 mg/l NaClO induced chromosome aberrations in the Allium cepa test at acid pH, but concentrations up to 0.5 mg/l of all the disinfectants were negative at neutral pH. Concentrations ranging from 0.1 to 0.5 mg/l NaClO, ClO(2,) and PAA induced micronuclei in Vicia faba at acid pH, while 1-2 mg/l NaClO and ClO(2) and 0.5-2 mg/l PAA gave positive responses at neutral pH. Most of concentrations of ClO(2) produced positive responses in the Tradescantia micronucleus test. In general, the highest levels of genotoxicity were observed under acid conditions; at acid pH, significant effects were induced by low concentrations of ClO(2) and PAA. Since the test concentrations of disinfectants are typical of those encountered in the biocidal treatment of tap water and similar concentrations are consumed daily by a large number of people, the genotoxicity of these compounds may constitute a significant public health concern.

The mutagenic hazards of aquatic sediments: a review

Sediments are the sink for particle-sorbed contaminants in aquatic systems and can serve as a reservoir of toxic contaminants that continually threaten the health and viability of aquatic biota. This work is a comprehensive review of published studies that investigated the genotoxicity of sediments in rivers, lakes and marine habitats. The Salmonella mutagenicity test is the most frequently used assay and accounts for 41.1% of the available data. The Salmonella data revealed mutagenic potency values for sediment extracts (in revertants per gram dry weight) that spans over seven orders of magnitude from not detectable to highly potent (10(5) rev/g). Analyses of the Salmonella data (n=510) showed significant differences between rural, urban/industrial, and heavily contaminated (e.g., dump) sites assessed using TA98 and TA100 with S9 activation. Additional analyses showed a significant positive correlation between Salmonella mutagenic potency (TA98 and TA100 with S9) and PAH contamination (r2=0.19-0.68). The second and third most commonly used assays for the analysis of sediments and sediment extracts are the SOS Chromotest (9.2%) and the Mutatox assays (7.8%), respectively. These assays are frequently used for rapid initial screening of collected samples. A variety of other in vitro endpoints employing cultured fish and mammalian cells have been used to investigate sediment genotoxic activity. Endpoints investigated include sister chromatid exchange frequency, micronucleus frequency, chromosome aberration frequency, gene mutation at tk and hprt loci, unscheduled DNA synthesis, DNA adduct frequency, and DNA strand break frequency. More complex in vivo assays have documented a wide range of effects including neoplasms and preneoplastic lesions in fish and invertebrate exposed ex situ. Although costly and time consuming, these assays have provided definitive evidence linking sediment contamination and a variety of genotoxic and carcinogenic effects observed in situ.

A new approach to evaluating the toxicity and genotoxicity of disinfected drinking water

The aim of this study was to evaluate the formation of toxic and genotoxic compounds in surface drinking waters treated with two widely used disinfectants, sodium hypochlorite (NaClO) and chlorine dioxide (ClO(2)), and a new disinfectant, peracetic acid (PAA). For this purpose a pilot plant was set up to add these biocides continuously to pre-filtered lake water flowing into three different basins. During three seasonal experiments, short-term in vivo tests (with plant, fish and molluscs) and in vitro tests (with bacteria, yeast and human cells) were carried out to evaluate the formation of genotoxic disinfection by-products (DBPs). Gas chromatography/mass spectrometry (GC/MS) was used to identify DBPs produced during the different treatments, microbiological analyses were performed to test the biocidal activity of the disinfectants, and chemical analyses were carried out to evaluate the quality of the water. The pilot drinking water plant under study was useful in studying the toxicity and genotoxicity of disinfected drinking water with this combined chemical/biotoxicological approach. This paper describes the setting up of the pilot plant and sets out/reports the results of the microbiological and chemical analyses.

Toxicological characterization of the new water cleaning product and its waste by-product

Water extracts genotoxicity of the coagulant produced from industrial waste (red mud and waste base) and its waste mud remained after waste water treatment by the coagulation/flocculation process were studied. Tests were conducted in order to confirm nontoxicity of this new product prior to commercial production and usage and also to recommend a safe way for a handling and disposal of the remaining waste material. The toxicity investigation included (i) determining frequency of the cell survival, (ii) the Ames assays, (iii) micronucleus assay, and (iv) cell proliferation kinetics (expressed as mitotic index). These techniques were also employed in toxicity testing of the different concentrations of metal salts, zinc chloride, and lead nitrate in this case since these two elements were present in high concentrations in the waste water intended for the purification with the new coagulant. Mixture of metal salts in the concentrations that represent maximum allowed values for water extracts of technological waste was also tested. Two strains of Salmonella typhimurium, TA98, and TA100 were used for determining cytotoxicity and for the Ames test, while the cytogenetic investigations were performed on human peripheral blood lymphocytes. Water extracts of the coagulant and its waste mud did not induce a significant increase of the micronuclei in human peripheral blood lymphocytes. They also did not disturb lymphocyte proliferation kinetics in vitro. As regards lead nitrate it proved not to be cytotoxic on bacterial strains in the tested concentration range (1-100 mg/L), whereas zinc chloride showed cytotoxic effect for the concentrations above 25 mg/L. The Ames test results for the noncytotoxic concentrations of these metals were negative. Comparing to the negative control a significantly higher number of the micronuclei was determined after the treatment of the whole blood with 100 mg/L of zinc chloride, as well as with 10 and 100 mg/L of lead nitrate. A linear, dose dependent increase was obtained for both salts. Similar results were obtained on the basis of the mitotic index.

Genotoxicity of surface water treated with different disinfectants using in situ plant tests

Disinfection of surface drinking water, in particular water chlorination, results in many by-products with potential genotoxic and/or carcinogenic activity. In the present study, we evaluated the genotoxicity of surface water after treatment with different disinfectants by means of in situ plant genotoxicity assays (micronucleus and chromosomal aberration tests) which can detect both clastogenic and aneugenic effects. The study was carried out at a pilot plant using lake water after sedimentation and filtration. This water supplied four stainless steel basins: three basins were disinfected with sodium hypochlorite, chlorine dioxide, and peracetic acid and the fourth basin containing untreated lake water was used as a control. Plants were exposed in situ in the basins. The study was carried out using water collected in different seasons over a period of about 1 year in order to assess the treatments in different physical and chemical lake water conditions. The micronucleus test in root cells of Vicia faba (Vicia faba/MCN test) revealed genotoxicity in many samples of disinfected water. The micronucleus test in Tradescantia pollen cells and the chromosome aberration test in root cells of Allium cepa showed genotoxic effects only in some disinfected samples, but also revealed genotoxicity in raw water. The results of the study indicated that the Vicia faba/MCN test was the most sensitive plant assay for disinfected water and that peracetic acid disinfection produced similar or lower genotoxicity than sodium hypochlorite or chlorine dioxide treatment.

PAH and metal mixtures in New Orleans soils and sediments

The purpose of this study is to determine the degree of PAH contamination and the association of PAHs with inorganic substances in soils and sediments of New Orleans. Bonnet Carré Spillway (BCS) (n = 5) provides modern baseline data, while urban soil samples (CTY) (n = 27) and sediment samples from Bayou St. John (BSJ) (n = 11) provide experimental data for New Orleans. Soil samples were collected from the top 2.5 cm of the surface, air-dried, and sieved (2 mm). Sediments samples were collected with a Wildco-Ekman bottom dredge, air-dried and finely ground. Accelerated solvent extraction (ASE) was used to release PAHs from the samples and analysis was conducted with gas chromatography-mass spectrometry (GC-MS). Metals were extracted using a 5:1 ratio of 1 mol/L nitric acid (room temperature) for soil and sediment samples, shaken for 2 h, centrifuged (1000 x g for 15 min) and filtered. Metal analysis was done by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Mann-Whitney tests show PAH differences (P < 0.001). Ranking of total PAHs is, BSJ sediments (10.3 mg/kg) > CTY soils (3.7 mg/kg) > BCS alluvium (0.28 mg/kg). The sum of the metals are similar for BSJ sediments (698 mg/kg) and CTY soils (679 mg/kg) and significantly lower for BCS (189 mg/kg). Manganese of these samples is similar for each site. For paired samples, Pearson Product Moment Correlation tests reveal that many PAHs are strongly associated with each other at all locations. For BCS alluvium and BSJ sediments, total PAHs are not significantly associated with total metals. For CTY, most pairs of metals are significantly associated, and total soil PAHs are strongly associated with total soil metals (correlation 0.78, P = 4.9 x 10(-4)). The linear model, total soil PAH = 136.3 + 6.25 (total soil metals) forms the basis for a predicted PAH map of New Orleans. Previous empirical research demonstrates an association between soil lead and children's lead exposure. This study indicates that PAHs are part of the soil mixture of accumulated substances and by-products of industrial society that presents exposure potential in cities.

Biomonitoring the genotoxicity of environmental factors with transgenic plants

All organisms must react to constantly changing surroundings. Environmental factors are thus powerful forces continuously shaping the genomes of all species. Induced genetic changes can be followed using a biomonitor - a living organism that reacts to a given compound in the environment. A vital but challenging task is identifying organisms with which to study the influence of changing environmental conditions. Plants are especially valuable biomonitors. Here, we describe the use of transgenic plant systems to evaluate the genotoxicity of chemical and radiological compounds. We evaluate the potential of further transgene-based systems for studying somatic and germ-line mutations.

Interactions of chromium with microorganisms and plants

Chromium is a highly toxic non-essential metal for microorganisms and plants. Due to its widespread industrial use, chromium (Cr) has become a serious pollutant in diverse environmental settings. The hexavalent form of the metal, Cr(VI), is considered a more toxic species than the relatively innocuous and less mobile Cr(III) form. The presence of Cr in the environment has selected microbial and plant variants able to tolerate high levels of Cr compounds. The diverse Cr-resistance mechanisms displayed by microorganisms, and probably by plants, include biosorption, diminished accumulation, precipitation, reduction of Cr(VI) to Cr(III), and chromate efflux. Some of these systems have been proposed as potential biotechnological tools for the bioremediation of Cr pollution. In this review we summarize the interactions of bacteria, algae, fungi and plants with Cr and its compounds.