Polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Bizerte Lagoon,Tunisia: levels,sources, and toxicological significance

To assess the status of polycyclic aromatic hydrocarbon (PAH) contamination in sediments from the Bizerte Lagoon (northern Tunisia), 18 surface sediment samples were collected in March 2011 and analyzed for 14 US Environmental Protection Agency priority PAHs by high-performance liquid chromatography. The total concentrations of the 14 PAHs (ΣPAHs) ranged from 16.9 to 394.1 ng g^?1 dry weight (dw) with a mean concentration of 85.5 ng g^?1 dw. Compared with other lagoons, coasts, and bays in the world, the concentrations of PAHs in surface sediments of the Bizerte Lagoon are low to moderate. The PAHs’ composition pattern was dominated by the presence of four-ring PAHs (45.8 %) followed by five-ring (26.8 %) and three-ring PAHs (12.7 %). The PAH source analysis suggested that the main origin of PAHs in the sediments of the lagoon was mainly from pyrolytic sources. According to the numerical effect-based sediment quality guidelines of the USA, the levels of PAHs in the Bizerte Lagoon should not exert adverse biological effects. The total benzo[a]pyrene toxicity equivalent values calculated for the samples varied from 3.1 to 53.7 ng g^?1 dw with an average of 10.6 ng g^?1 dw.     

Impact of rapid urbanisation and industrialisation on river sediment metal contamination

This study aimed at evidencing contaminant inputs from a rapidly growing population and the accompanying anthropogenic activities to river sediments. The Fez metropolitan area and its impacts on the Sebou's sediments (the main Moroccan river) were chosen as a case study. The Fez agglomeration is surrounded by the river Fez, receiving the wastewaters of this developing city and then flowing into the Sebou. The sediment cores from the Fez and Sebou Rivers were extracted and analysed for major elements, butyltins and toxic metals. Normalised enrichment factors and geoaccumulation index were calculated. Toxicity risk was assessed by two sets of sediment quality guideline (SQG) indices. A moderate level of contamination by butyltins was observed, with monobutyltin being the dominant species across all sites and depths. The lowest level of metal pollution was identified in the Sebou's sediments in upstream of Fez city, whilst the Fez' sediments were heavily polluted and exhibited bottom-up accumulation trends, which is a clear signature of recent inputs from the untreated wastewaters of Fez city. Consequently, the sediments of Fez and Sebou at the downstream of the confluence were found to be potentially toxic, according to the SQG levels. This finding is concerned with aquatic organisms, as well as to the riverside population, which is certainly exposed to these pollutants through the daily use of water. This study suggests that although Morocco has adopted environmental regulations aiming at restricting pollutant discharges into the natural ecosystems, such regulations are neither well respected by the main polluters nor efficiently enforced by the authorities.     

Tolerance values of benthic macroinvertebrates for stream biomonitoring: assessment of assumptions underlying scoring systems worldwide

Tolerance values (TVs) based on benthic macroinvertebrates are one of the most widely used tools for monitoring the biological impacts of water pollution, particularly in streams and rivers. We compiled TVs of benthic macroinvertebrates from 29 regions around the world to test 11 basic assumptions about pollution tolerance, that: (1) Arthropoda are < tolerant than non-Arthropoda; (2) Insecta < non-Insecta; (3) non-Oligochaeta < Oligochaeta; (4) other macroinvertebrates < Oligochaeta + Chironomidae; (5) other macroinvertebrate taxa < Isopoda + Gastropoda + Hirudinea; (6) Ephemeroptera + Plecoptera + Trichoptera (EPT) < Odonata + Coleoptera + Heteroptera (OCH); (7) EPT < non-EPT insects; (8) Diptera < Insecta; (9) Bivalvia < Gastropoda; (10) Baetidae < other Ephemeroptera; and (11) Hydropsychidae < other Trichoptera. We found that the first eight of these 11 assumptions were supported despite regional variability. In addition, we examined the effect of Best Professional Judgment (BPJ) and non-independence of TVs among countries by performing all analyses using subsets of the original dataset. These subsets included a group based on those systems using TVs that were derived from techniques other than BPJ, and groups based on methods used for TV assignment. The results obtained from these subsets and the entire dataset are similar. We also made seven a priori hypotheses about the regional similarity of TVs based on geography. Only one of these was supported. Development of TVs and the reporting of how they are assigned need to be more rigorous and be better described.     

Feature extraction using Hough transform for solid waste bin level detection and classification

This paper deals with the solid waste image detection and classification to detect and classify the solid waste bin level. To do so, Hough transform techniques is used for feature extraction to identify the line detection based on image’s gradient field. The feedforward neural network (FFNN) model is used to classify the level content of solid waste based on learning concept. Numbers of training have been performed using FFNN to learn and match the targets of the testing images to compute the sum squared error with the performance goal met. The images for each class are used as input samples for classification. Result from the neural network and the rules decision are used to build the receiver operating characteristic (ROC) graph. Decision graph shows the performance of the system waste system based on area under curve (AUC), WS-class reached 0.9875 for excellent result and WS-grade reached 0.8293 for good result. The system has been successfully designated with the motivation of solid waste bin monitoring system that can applied to a wide variety of local municipal authorities system.     

Organochlorine pesticide residue levels in blood serum of inhabitants from Veracruz, Mexico

The objective of the present study was to monitor the levels of organochlorine pesticides HCB; α-, β-, γ-HCH; pp'DDE; op'DDT; and pp'DDT in blood serum of Veracruz, Mexico inhabitants. Organochlorine pesticides were analyzed in 150 blood serum samples that constituted that which remained after clinical analyses, using gas chromatography-electron-capture detection (GC-ECD). The results were expressed as milligrams per kilogram on fat basis and micrograms per liter on wet weight. Only the following pesticides were detected: p,p'-DDE was the major organochlorine component, detected in 100% of samples at mean 15.8 mg/kg and 8.4 μg/L; p,p'-DDT was presented in 41.3.% of monitored samples at mean 3.1 mg/kg and 1.4 μg/L; β-HCH was found in 48.6% of the samples at mean 4.9 mg/kg and 2.7 μg/L; op'DDT was determined to be in only 3.3% of monitored samples at mean 2.7 mg/kg and 1.4 μg/L. The pooled samples divided according to sex showed significant differences of β-HCH and pp'DDE concentrations in females. The samples grouped according to age presented the third tertile as more contaminated in both sexes, indicating age as a positively associated factor with serum organochlorine pesticide levels in Veracruz inhabitants.     

Bioremediation of heavy metals using biostimulation in laboratory bioreactor

The present research study investigates bioremediation potential of biostimulated microbial culture isolated from heavy metals waste disposal contaminated site located at Bhayander (east), Mumbai, India. The physicochemical and microbial characterization including heavy metal contaminants have been studied at waste disposal site. The microorganisms adapted at heavy metal-contaminated environment were isolated, cultured, and biostimulated in minimal salt medium under aerobic conditions in a designed and developed laboratory bioreactor. Heavy metals such as Fe, Cu, and Cd at a selected concentration of 25, 50, and 100?μg/ml were taken in bioreactor wherein biostimulated microbial culture was added for bioremediation of heavy metals under aerobic conditions. The remediation of heavy metals was studied at an interval of 24?h for a period of 21?days. The biostimulated microbial consortium has been found effective for remediation of Cd, Cu, and Fe at higher concentration, i.e., 100?mg/l up to 98.5%, 99.6%, and 100%, respectively. Fe being a micronutrient was remediated completely compared to Cu and Cd. During the bioaccumulation of heavy metals by microorganisms, environmental parameters such as pH, total alkalinity, electronic conductivity, biological oxygen demand, chemical oxygen demand, etc. were monitored and assessed. The pilot scale study would be applicable to remediate heavy metals from waste disposal contaminated site to clean up the environment.     

Characterizing the intrinsic bioremediation potential of 1,4-dioxane and trichloroethene using innovative environmental diagnostic tools

An intrinsic biodegradation study involving the design and implementation of innovative environmental diagnostic tools was conducted to evaluate whether monitored natural attenuation (MNA) could be considered as part of the remedial strategy to treat an aerobic aquifer contaminated with 1,4-dioxane and trichloroethene (TCE). In this study, advanced molecular biological and stable isotopic tools were applied to confirm in situ intrinsic biodegradation of 1,4-dioxane and TCE. Analyses of Bio-Trap? samplers and groundwater samples collected from monitoring wells verified the abundance of bacteria and enzymes capable of aerobically degrading TCE and 1,4-dioxane. Furthermore, phospholipid fatty acid analysis with stable isotope probes (PLFA-SIP) of the microbial community validated the ability for microbial degradation of TCE and 1,4-dioxane. Compound specific isotope analysis (CSIA) of groundwater samples for TCE resulted in δ(13)C values that indicated likely biodegradation of TCE in three of the four monitoring wells sampled. Results of the MNA evaluation showed that enzymes capable of aerobically degrading TCE and 1,4-dioxane were present, abundant, and active in the aquifer. Taken together, these results provide direct evidence of the occurrence of TCE and 1,4-dioxane biodegradation at the study site, supporting the selection of MNA as part of the final remedy at some point in the future.     

Monitoring of ozone effects on the vitality and increment of Norway spruce and European beech in the Central European forests

The ozone effect on Norway spruce (Picea abies (L) Karst.) and European beech (Fagus sylvatica L.) was studied on 48 monitoring plots in 2005-2008. These plots represent two major forest tree species stands of different ages in eight regions of the Czech Republic. The forest conditions were represented by defoliation and the annual radial increment of individual trees. The ozone exposure was assessed by using modeled values of mean annual O(3) concentration and the AOT40 index. The malondialdehyde (MDA) content of the foliage was analysed and used as an indicator of oxidative stress. The correlation analysis showed a significant relation of Norway spruce defoliation to the AOT40 exposure index, and European beech defoliation to the MDA level. The radial increment response to ozone was significant only for the European beech: (a) the correlation analysis showed its decrease with increasing AOT40; (b) the regression model showed its decrease with increasing mean annual ozone concentration only at lower altitudes (<700 m a.s.l.).     

Fragmentation of extracellular DNA by long-term exposure to radiation from uranium in aquatic environments

Persistent harmful scenarios associated with disposal of radioactive waste, high-background radiation areas and severe nuclear accidents are of great concern regarding consequences to both human health and the environment. Of particular concern is the extracellular DNA in aquatic environments contaminated by radiological substances. Strand breaks induced by radiation promote decrease in the transformation efficiency for extracellular DNA. The focus of this study is the quantification of DNA damage following long-term exposure (over one year) to low doses of natural uranium (an alpha particle emitter) to simulate natural conditions, since nothing is known about alpha radiation induced damage to extracellular DNA. A high-resolution Atomic Force Microscope was used to evaluate DNA fragments. Double-stranded plasmid pBS as a model for extracellular DNA was exposed to different amounts of natural uranium. It was demonstrated that low concentrations of U in water (50 to 150 ppm) produce appreciable numbers of double strand breaks, scaling with the square of the average doses. The importance of these findings for environment monitoring of radiological pollution is addressed.     

Gene-TEQ--a standardized comparative assessment of effects in the comet assay using genotoxicity equivalents

Existing methods for the comparison of genotoxic effects in the comet assay bear considerable disadvantages such as the problem to link information about concentration dependence and severity of effects. Moreover, given the lack of standardized protocols and the use of various standards, it may be extremely difficult to compare different studies. In order to provide a method for standardized comparative assessment of genotoxic effects, the concept of genotoxicity equivalents (Gene-TEQ) was developed. As potential reference compounds for genotoxic effects, three directly acting (N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), methyl-methanesulfonate, and N-methyl-N-nitrosourea) and three indirectly acting (cyclophosphamide, dimethylnitrosamine, and 4-nitroquinoline-oxide) genotoxic substances were compared with respect to their cytotoxic (neutral red) and genotoxic (comet assay) concentration-response profiles in the permanent fish cell line RTL-W1. For further comparison, two sediment extracts from the upper Danube River were investigated as environmental samples. Based on the results of cytotoxicity and genotoxicity testing, MNNG was selected as the reference compound. At several exposure levels and durations, genotoxic effects of both the other pure substances and the environmental samples were calculated as percentages of the maximum MNNG effect and related to the absolute MNNG effect (EC values). Thus, genotoxicity equivalent factors (Gene-TEQs) relative to MNNG could be calculated. Gene-TEQs can easily be applied to pure substances, mixtures and field samples to provide information about their toxicity relative to the reference compound. Furthermore, the Gene-TEQ concept allows a direct comparison of environmental samples from different laboratories.