The cytotoxicity of nici2 for mammalian cells in culture†

The effects of NiCl₂ were studied in two human cell lines, HeLa and diploid embryonic fibroblasts as well as in V79 Chinese hamster cells and in L‐A mouse fibroblasts. NiCl₂ produces a dose‐dependent depression of proliferation, mitotic rate, and viability, accompanied by an increasing release of lactic dehydrogenase and stimulation of lactic acid production. The plating efficiency is reduced, as are DNA and protein synthesis and, to a lesser degree, RNA synthesis.

The cytotoxicity of NiCl₂ is comparable in degree to those of PbCl₂ and MnCl₂, but is weaker than those of HgCl₂ and CdCl₂. However, the different sensitivities of different cell lines must also be considered.

NiCl₂ effects are more severe in serum‐free medium than in medium containing serum or serum albumin indicating that serum constituents, notably albumin, bind the metal effectively and inhibit cellular uptake; this confirms earlier reports on the serum binding and slow uptake of NiCl₂.

Synchronized cells are most sensitive in the Gl and early S phases of the cell cycle. In the Painter test the depression of DNA synthesis persists following cessation of exposure to NiCI₂. These findings contribute an explanation for the known genotoxic effects of nickel.     

Model reactions of chromium compounds with mammalian and bacterial cells†

Chromate uptake, reduction, cytotoxicity and mutagenicity were studied with human red blood cells, Chinese hamster ovary (CHO) cells and/or Salmonella typhimurium mutant cells. All cell types rapidly took up chromates whereas chromium(III) salts were excluded under the experimental conditions. Red blood cells reduced and accumulated chromium from chromate. At concentrations above 0.1 mM, chromate inactivated the red cell chromate carrier. Chromate above 0.01 mM inhibited CHO cell proliferation irrespective of the cations present. Chromate and two chromium(III) complexes were mutagenic with Salmonella mutants in the Ames’ assay. A model for chromate metabolism and genotoxicity is proposed.     

Induction of mercury‐binding peptide in whole cells and anucleated cells of Acetabularia calyculus

The present study reports the isolation and partial purification of a mercury‐binding polypeptide in whole and anucleated cells of Acetabularia calyculus. Sephadex G‐75 Gel filtration showed that cells exposed to Hg exhibit a major peak of protein(s) concomitant with both, a major peak of Hg (revealed by atomic absorption spectroscopy), and the major peak of mercury‐thiolate complex (based on a high 254 nm absorbance) accompanied by high content of SH groups. SDS‐Page electrophoresis showed that this peak contains one major polypeptide of apparent molecular weight 27.000 dalton. These results are in agreement with our previous finding of unusually high bioconcentration factor of Hg in Acetabularia related to the induction of a polypeptide in both, whole and anucleated cells of Acetabularia, in presence of Hg.     

Evaluation and remediation of organics,nutrients and heavy metals in landfill leachate – a case study in Beijing

Leachate pollution in landfill sites is a major source of environmental concern. This study evaluates organics, nutrients and heavy metals in a landfill site in Beijing, and introduces a method combining coagulation–flocculation with filtration for the advanced treatment of leachate. The results confirm that COD_Cr, TN, NH₄⁺ ? N, TP, Mn and As in leachate treated by an anaeobic–oxic biological method are unable to meet discharge or surface water quality standards. When treated with coagulation–flocculation combined with filtration under optimal conditions (cationic polyacrylamide dosage of 8.0 mg/L; polyaluminium chloride dosage of 350 mg/L; 0.4–0.6 mm ceramsite media in the filtration process), the residual NH₄⁺? N, TN, Mn and As in the leachate meet the maximum allowed values for landfill leachate discharge or surface water quality standards in China; the exceptions are chemical oxygen demand and total phosphorus. Leachate treatment processes could be further strengthened or improved.     

Uranium and other trace elements’ distribution in Korean granite: implications for the influence of iron oxides on uranium migration

To understand trace radionuclide (uranium) migration occurring in rocks, a granitic batholith located at the Korea Atomic Energy Research Institute (KAERI) site was selected and investigated. The rock samples obtained from this site were examined using mineralogical methods, including scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The changes in the distribution pattern of uranium (U) and small amounts of trace elements, and the mineralogical textures affected by weathering, were examined. Based on the element distribution analyses, it was found that Fe²⁺ released from fresh biotite is oxidized in short geological time, forming amorphous iron oxides, such as ferrihydrite, around silicate minerals. In that case, the amorphous ferrihydrite does not show distinct adsorption for U. However, as it gradually crystallizes to goethite or hematite, the most U-rich phases were found to be associated with the secondary iron oxides having granular forms. This evidence suggests that the geological subsurface environment is favorable for the crystallized iron oxides to keep their structures more stable for a long time as compared with the amorphous phases. There is a possibility that the long residence of U which is in contact with the stable crystalline phases of iron may finally lead to the partial sequestration of U in their structure. Consequently, it seems that Fe-oxide crystallization can be a dominating mechanism for U uptake and controls long-term U transport in granites with low U contents.     

Investigating into composition,distribution, sources and health risk of phthalic acid esters in street dust of Xi’an City,Northwest China

Phthalic acid esters (PAEs) are widely used as plasticizers and in consumer products, which may enter the environment and present risks to human health. U.S. EPA classifies six PAEs as priority pollutants, which could be accumulated in street dust at the interface of atmosphere, biosphere and geosphere. This study collected a total of 58 street dust samples from Xi’an City in Northwest China and analyzed for concentrations of the priority PAEs. Composition, distribution, sources and health risk of the PAEs were further examined. All the priority PAEs were detected in the street dust. The concentrations of individual PAEs varied between not detected and 183.19 mg/kg. The sum of the 6 priority PAEs (∑6PAEs) ranged from 0.87 to 250.30 mg/kg with a mean of 40.48 mg/kg. The most abundant PAEs in the street dust were di-n-butyl phthalate and di (2-ethylhexyl) phthalate (DEHP). Higher concentrations of ∑6PAEs in the street dust were found in the south and west parts of Xi’an City as well as its urban center, which were possibly attributed to the prevailing northerly Asian winter monsoon. The PAEs in the street dust originated mainly from wide application of plasticizers as well as cosmetics and personal care products. The main pathways of human exposure to PAEs in the street dust were ingestion and dermal adsorption of dust particles. The non-cancer risk of human exposure to PAEs in the street dust was relatively low, while the risk to children was higher than that to adults. The cancer risk of human exposure to DEHP in the street dust was lower than the standard limit value of 10^?6.     

Analysis of Cd,Cu, Pb,Zn, Hg and Mn in kidneys and liver from human cadavers – A case study in South Western Nigeria

In this study, autopsy tissue samples from human liver and kidneys were analysed for Cd, Cu, Pb, Zn, Hg and Mn in 25 subjects (16 males and 9 females) ranging in age from 2 to 70 years. Tissue samples that were pathologically normal were obtained at postmortem and concentrations of metals were determined. In both kidneys and liver, the concentrations of metals followed the order Cd > Hg > Pb > Zn > Mn > Cu irrespective of gender and age group, except in female kidneys where the order was Cd > Pb > Hg > Zn > Mn > Cu. Generally, males had higher concentrations of metals in both the kidneys and liver. Significant correlations of the metals were found in kidney and liver tissues.     

Vigilance of mustached tamarins in single-species and mixed-species groups—the influence of group composition

Species that participate in mixed-species groups (MSG) may have complementary roles in antipredator strategies. We studied vigilance in mustached tamarins (Saguinus mystax), small arboreal primates that form stable mixed-species groups with saddleback tamarins (Saguinus fuscicollis), in order to examine how the direction of vigilance changes with different species group compositions and whether the division of labor between the two species can be confirmed. We did so by comparing quantitative and qualitative differences in vigilance behavior between same individuals in and out of association (case A); MSG and single-species groups of the same total group size from two different populations (case B); and MSG of the same group size but with a different ratio of conspecifics to heterospecifics (case C). We predicted that individuals would increase downward scanning when heterospecifics are absent or their percentage is low, but total vigilance would increase only in case A due to the group size effect. However, mustached tamarins increased total vigilance due to horizontal scanning in cases A and C, and the predictions were confirmed only in small-sized groups in case B. Thus, we found indications that associating tamarin species in MSG might complement each other in the direction of vigilance, but the division of labor alone does not satisfactorily explain all the findings. There appear to be other mechanisms at work that define how direction of vigilance changes with group size and species composition. Complementarity of species probably occurs due to species vertical stratification rather than differences in the direction of vigilance.     

Growth dynamics of Saccharina latissima (Laminariales,Phaeophyceae) in Aarhus Bay,Denmark, and along the species’ distribution range

Growth dynamics of Saccharina latissima in a Danish embayment (56°03.793N, 10°16.148E) were investigated through an annual cycle (March 1999–March 2000) and related to patterns found in previous studies covering the distribution range of the species. The kelps exhibited meristematic growth as well as distal tissue loss all year around. Elongation rate peaked in spring (March–May, 0.75 cm day^?1), whereas maximum biomass growth occurred in May–July at higher insolation. S. latissima accumulated nitrogen (N) in November–March, when ambient N levels were high and the fast growth in March–July was followed by a depletion of these reserves. Light regimes and seasonal fluctuations of nutrients were, thus, major factors explaining the seasonal growth pattern of S. latissima in this temperate bay. Differences in light and exposure along depth gradients affected the growth, loss and storage product dynamics. High losses of N and carbon (C) through summer abscission of distal tissue question the efficiency of translocation, especially at shallower depths, where losses are accelerated by, e.g., high temperature. A large-scale comparison further highlighted that warming advanced the timing, increased the level of peak growth and also seemed to expand the growth period. Growth rates of the studied Danish population fell in the low end of the range for similar latitudes and temperatures, probably due to sub-optimal salinities (avg. 23.3 psu) in combination with periodically high summer temperatures (max. 21.1 °C).     

Selenium and hazardous elements distribution in plant–soil–water system and human health risk assessment of Lower Cambrian,Southern Shaanxi,China

The natural selenium poisoning due to toxic Se levels in food chain had been observed in humans and animals in Lower Cambrian outcrop areas in Southern Shaanxi, China. To find out the distribution pattern of selenium and other hazardous elements in the plant, soil and water of Lower Cambrian in Southern Shaanxi, China, and their possible potential health risk, a total of 30 elements were analyzed and the health risk assessment of 18 elements was calculated. Results showed that the soil, plant and natural water of Lower Cambrian all had relatively high Se levels. In Lower Cambrian, the soil was enriched with Se, As, Ba, Cu, Mo, Ni, Zn, Ga, Cd and Cr (1.68 < I_geo < 4.48, I_geo; geo-accumulation index). In same plants, the contents of Se, Cd and Zn (except Cd in corn and rice, Zn in potato and corn) of Lower Cambrian were higher than that of the other strata. Ba and Ga in natural water were higher than that of the other strata, while K and Cs were opposite. The health risk assessment results showed that the people living in outcrop areas of Lower Cambrian had both high total non-carcinogenic risk of 18 elements (HI = 16.12, acceptable range: < 1) and carcinogenic risk of As (3.98E−04, acceptable range: 10⁻⁶–10⁻⁴). High contents of Se, As, Mo and Tl of Lower Cambrian may pose a health risk to local people, and food intake was the major pathway. For minimizing potential health risk, the local inhabitants should use the mix-imported food with local growing foods.

     

Size,spatial, and bathymetrical distribution of the ascidian Halocynthia papillosa in Mediterranean coastal bottoms: benthic–pelagic coupling implications

Benthic suspension feeders are abundant in Mediterranean coastal environments, though most of them are threatened due to overexploitation, climate change impacts, and unregulated diving or fishing practices. Little is known about most of the coastal communities in terms of large-scale distribution and realistic benthic–pelagic coupling implications, which are keys to understand and manage those threatened ecosystems. The active suspension feeder Halocynthia papillosa (one of the most common ascidian species of the Mediterranean Sea) was selected as a model organism to help to understand the ecological role in benthic–pelagic coupling processes and its importance as a carbon sink (an essential ecosystem service). The spatial and bathymetrical distribution of this organism has been studied using remotely operated vehicle video transects. The species was distributed throughout the study area, with a maximum density of 4 specimens m^?2. The highest abundances and the biggest sizes were observed on the range of 20–50 m depth. The role as carbon and nitrogen sink of this suspension feeder has been quantified coupling distribution data with existing in situ studies of feeding and respiration. Along the 1.24 ha of the study area, H. papillosa yearly ingested 519.4 g C and 31.4 g N and retained 20.2 g C. As long as the physiological data are known, this new methodology could be very useful in assessing bentho–pelagic links and the capacity of being C and N sinks of a wide range of species. This new approach may be essential for the future management of benthic communities.     

Accumulation, contamination, and seasonal variability of trace metals in the coastal zone – patterns in a seagrass meadow from the Mediterranean

Amongst a plethora of threats to seagrass ecosystems, contamination with heavy metals may well be one of the most significant. We therefore set out to track contamination levels with Cu, Zn, Pb and Cd in the principal autotrophic compartments and sediments of a meadow of Posidonia oceanica in the Gulf of Naples, Mediterranean Sea. With respect to metal levels, leaves and their associated epibiota are certainly not a homogenous compartment, as might perhaps be inferred from the common use of the term “leaf–epiphyte complex” in the literature. Save for Cu, all metal species analysed showed appreciable differences in concentration between seagrass leaves and epibiota. These results give strength to our argument that in ecotoxicological work leaves and epibiota should not be treated as a single unit. Although absolute differences in trace-metal levels among sampling periods varied somewhat with the specific component analysed (i.e. macrophyte organs, epibiota, sediment), an overall trend of markedly higher heavy-metal levels during the winter season is a striking one. Whilst annual cycles in growth dynamics of the seagrasses explain a significant fraction of the temporal variance, seasonality in productivity is a doubtful explanation for similar patterns in non-living sedimentary components; consideration of additional variables therefore seems sensible. As variables with consistent explanatory powers we suggest: (1) seasonal cycles in storm frequency and amplitude which remobilise metals bound in the sediments of the sea floor, and (2) increased precipitation during the cold season which may significantly increase marine metal levels through elevated weathering of rocks and elevated fluvial inputs of anthropogenic contaminant loads. Whereas Cd and Pb concentrations in seagrass leaves from the Gulf of Naples fall within the range for coastal areas subjected to low levels of heavy-metal pollution, Cu and Zn reach levels typical of highly contaminated regions, such as the waters bordering major coastal cities. Any direct comparisons of the pollution status of seagrass beds between different geographic areas are, however, likely to be confounded by the indiscriminate application of the “leaf–epiphyte complex”: the magnitude of the confounding effect depends on the ratio of epibiota/leave biomass, time of sampling, and metal species analysed. Received: 15 May 1997 / Accepted: 2 February 1998     

Abundance and distribution of antibiotic resistance genes in a full-scale anaerobic–aerobic system alternately treating ribostamycin,spiramycin and paromomycin production wastewater

The occurrence of antibiotic-resistant bacteria and antibiotic resistance genes (ARGs) has been intensively investigated for wastewater treatment systems treating single class of antibiotic in recent years. However, the impacts of alternately occurring antibiotics in antibiotic production wastewater on the behavior of ARGs in biological treatment systems were not well understood yet. Herein, techniques including high-capacity quantitative PCR and quantitative PCR (qPCR) were used to investigate the behavior of ARGs in an anaerobic–aerobic full-scale system. The system alternately treated three kinds of antibiotic production wastewater including ribostamycin, spiramycin and paromomycin, which referred to stages 1, 2 and 3. The aminoglycoside ARGs (52.1–79.3%) determined using high-capacity quantitative PCR were the most abundant species in all sludge samples of the three stages. The total relative abundances of macrolide–lincosamide–streptogramin (MLS) resistance genes and aminoglycoside resistance genes measured using qPCR were significantly higher (P < 0.05) in aerobic sludge than in sewage sludge. However, the comparison of ARGs acquired from three alternate stages revealed that MLS genes and the aminoglycoside ARGs did not vary significantly (P > 0.05) in both aerobic and anaerobic sludge samples. In aerobic sludge, one acetyltransferase gene (aacA4) and the other three nucleotidyltransferase genes (aadB, aadA and aadE) exhibited positive correlations with intI1 (r ² = 0.83–0.94; P < 0.05), implying the significance of horizontal transfer in their proliferation. These results and facts will be helpful to understand the abundance and distribution of ARGs from antibiotic production wastewater treatment systems.

     

Spring sea ice photosynthesis,primary productivity and biomass distribution in eastern Antarctica, 2002–2004

While it is known that Antarctic sea ice biomass and productivity are highly variable over small spatial and temporal scales, there have been very few measurements from eastern Antarctic. Here we attempt to quantify the biomass and productivity and relate patterns of variability to sea ice latitude ice thickness and vertical distribution. Sea ice algal biomass in spring in 2002, 2003 and 2004 was low, in the range 0.01–8.41 mg Chl a m⁻², with a mean and standard deviation of 2.08 ± 1.74 mg Chl a m⁻² (n = 199). An increased concentration of algae at the bottom of the ice was most pronounced in thicker ice. There was little evidence to suggest that there was a gradient of biomass distribution with latitude. Maximum in situ production in 2002 was approximately 2.6 mg C m⁻² h⁻¹ with assimilation numbers of 0.73 mg C (mg Chl a)⁻¹ h⁻¹. Assimilation numbers determined by the ¹⁴C incubations in 2002 varied between 0.031 and 0.457 mg C (mg Chl a)⁻¹ h⁻¹. Maximum fluorescence quantum yields of the incubated ice samples in 2002 were 0.470 ± 0.041 with E _k indices between 19 and 44 μmol photons m⁻² s⁻¹. These findings are consistent with the shade-adapted character of ice algal communities. In 2004 maximum in situ production was 5.9 mg C m⁻² h⁻¹ with an assimilation number of 5.4 mg C (mg Chl a)⁻¹ h⁻¹. Sea ice biomass increased with ice thickness but showed no correlation with latitude or the time the ice was collected. Forty-four percent of the biomass was located in bottom communities and these were more commonly found in thicker ice. Surface communities were uncommon.     

Characterization and distribution of mineral content in fine and coarse airborne particle fractions by neutron activation analysis∗

Nowadays, much attention is devoted to the study of toxic elements at trace and sub-trace levels in the investigation of particulate matter composition, especially in PM₁₀ and PM_2.5. Furthermore, it should be considered that the behavior knowledge is an other important task for understanding such species. Finally, the determination of particular elements with a few data in literature can assume relevant importance in industrial processes (Pd, Rh, Ir, etc. for catalytic pot, Sm, Ce, Eu, etc. for optical fibers and electronic process). In this article, we apply a nuclear technique, i.e. Instrumental Neutron Activation Analysis, for the study of metal composition in fine and coarse fractions. This nuclear technique allows the determination of about 25 elements: for some of them, this is the first determination in the ambient air of Rome. The investigation was performed in a reserved area in downtown Rome during a 15-day intensive campaign. The sampled filters were irradiated at the nuclear reactor Triga Mark II (ENEA-Casaccia Laboratories) at neutron flux of 2.6?×?10¹²?n?cm^?2?s^?1 for 32.55?h. The measurements of the γ-ray allow the qualitative and quantitative analysis. The element levels in fine and coarse fractions will be shown with the correlations among some elements being more interesting in the toxicological field: basically, the concentrations are very low.     

Mercury distribution in the sediments of Ambarlı Port Area,Sea of Marmara (Turkey)

The purpose of this study is to investigate historical and current mercury (Hg) contamination in the surface and core sediments of the Ambarl? Port area. Textural parameters, total organic carbon (TOC), ²¹⁰Pb and total Hg (THg) contents were measured. Mercury contamination of the sediments was assessed on the basis of the enrichment factor (EF), anthropogenic factor (AF), index of geoaccumulation (Igeo) and corresponding sediment quality guidelines. Most surface sediment samples were also non-toxic with mercury concentrations below the effects range-low (ERL) value, but mercury levels at five stations were between ERL and effects range-median (ERM) values, where occasional adverse effects concerning risk analysis are expected. The EF and Igeo analysis showed that there was no significant mercury enrichment and contamination in the core sediment before the 1650s, but values increased from then onwards to 2009 (being especially accelerated in line with port activities from 1989), disclosing a serious ecotoxicological risk to sediment-inhabited marine organisms.     

Efficiency of Zn phytoextraction,biomass yield and formation of low-molecular-weight organic acids in S × rubens – a hydroponic experiment

The aim of the study was to estimate Zn phytoextraction and changes in biomass of S?×?rubens growing in modified Knop's solution with different levels of Zn addition (0.5, 1.0, 2.5 and 5.0?mM). Obtained results were correlated with secretion of selected low-molecular-weight organic acids (LMWOAs) in the rhizosphere, roots and leaves. An increase in Zn concentration in Knop's solution resulted in Zn accumulation in roots, shoots and leaves. The highest accumulation was observed for plants growing in 5?mM Zn, at concentration levels 4741.36?±?98.66, 1227.31?±?16.57 and 2241.65?±?34.90?mg?kg^?1 DW in roots, shoots and leaves, respectively. The bioaccumulation factor and the translocation factor for plants growing in 0.5, 1.0 and 2.5?mM Zn clearly indicate that this Salix taxon is an effective Zn accumulator. The general reduction of Salix biomass with an increase in Zn concentration in the solution was observed. In the rhizosphere, the total LMWOA concentration was almost 0.93?µmol?kg^?1 DM for control (Zn free) plants, while for 5.0?mM of Zn it was 4.9?µmol?kg^?1 DM. Increasing concentrations of acids were observed in roots (1.34 for the control and 5.57?µmol?kg^?1 DM for plants treated with 2.5?mM of Zn).     

Spatial distribution and controlling factors of heavy metals contents in paddy soil and crop grains of rice–wheat cropping system along highway in East China

There is consensus concerning the heavy metal pollution from traffic emission on roadside agricultural land. However, few efforts have been paid on examining the contamination characteristics of heavy metals in roadside paddy-upland rotation field, and especially in combination with detailed quantitative analysis. In this study, we investigated the concentrations of heavy metals (Pb, Cd, Cr and Zn) in soil and crop grains of the rice-wheat cropping system along a major highway in East China in 2008 and analyzed the spatial distribution characteristics of heavy metals and their influencing factors with GIS and Classification and Regression Trees (CART). Significantly elevated levels of heavy metals in soil, rice and wheat grains indicated the heavy metals contamination of traffic emission in roadside rice-wheat rotation field. The contamination levels of Cd, Cr and Zn in wheat grain were higher than rice grain, while that of Pb showed an opposite trend. Obvious dissimilarities in the spatial distributions of heavy metals contents were found between in the soil, rice and wheat grains, indicating that the heavy metals contents in the roadside crop grains were not only determined by the concentrations of heavy metals in the paddy soil. Results of CART analysis showed that the spatial variation of the heavy metals contents in crop grains was mainly affected by the soil organic matter or soil pH, followed by the distance from highway and wind direction. Our findings have important implications for the environmental assessment and crop planning for food security along the highway.     

δ13C and fatty acid composition of mesopelagic fishes in the South China Sea and their influence factors

Study of the ecology of mesopelagic fishes is central for assessing the active biological pump in the ocean, especially in the mesopelagic layers. The use of δ¹³C and fatty acid analysis can help to analysis the ecology of mesopelagic fishes. Here, we analysed the fatty acid composition of mesopelagic fishes from the continental northern slope of the South China Sea (NSSCS) and compared with nearshore SCS fishes and mesopelagic fishes collected from the Southern Ocean. The mesopelagic fishes had unusually high lipids, which resulted in Δδ¹³C values exceeding 1‰, more than the enrichment factor in the food web. The mesopelagic fishes had higher C18:1n-9/C18:1n-7 and C20:1n-9/ C18:1n-7 ratios compared with other fishes in the SCS, which confirmed that plankton were their main dietary source. The mesopelagic fishes from SCS and Southern Ocean had different ratios of C20:5n-3/C22:6n-3 (EPA/DHA), suggesting geographical locations and diet sources had obvious influence on their fatty acid composition. The SCS mesopelagic fishes had higher C20:4n-6/C22:6n-3 (ARA/DHA) and C20:4n-6/C20:5n-3 (ARA/EPA) ratios than mesopelagic fishes in the Southern Ocean, indicating the influence of physical factors on fatty acid composition. Thus, future studies of the fatty acids in mesopelagic fishes should consider both dietary sources and physical environments.