Comparative study of the fate and mobility of metals discharged in mining and urban effluents using sequential extractions on suspended solids

The fate, bioavailability and environmental impacts of metals discharged in municipal and mining wastewater discharge will depend to a large extent on chemical speciation and distribution. Previous studies on metal bioaccumulation have shown that total metal concentrations are not a good predictor of bioavailability in the dispersion plumes of municipal effluents. The objective of this study was to determine the solid phase speciation of metals in surface waters receiving urban and mining effluents in order to assess their fate and relative mobility in the receiving environment. Suspended particulate matter was sampled using sediment traps at several sites downstream of effluent outfall plumes as well as at reference upstream sites. Particulate metal in operationally defined fractions—exchangeable/carbonates, reducible, oxidisable and residual—were determined in suspended particulate matter with a series of selective chemical extractions. Metal enrichment in suspended particles was generally observed in both mining and urban effluent discharges. When compared to its receiving environment, the mining effluent appeared to release more particulate metals (Cu, Fe, Zn) in the most reactive fractions (i.e. exchangeable/carbonates + reducible forms, 23–43%), while other released metals, such as Cd and Mn, were predominantly in the least reactive forms (i.e., oxidisable + residual, 73–97%). In contrast, the reactivity of all particulate metals, with the exception of Mn, from the urban effluent was much higher, with up to 65, 42, 30 and 43% for Cd, Cu, Fe and Zn, respectively, in the two most reactive fractions. As expected in effluent dispersion plumes, parameters such as the organic carbon, Fe oxide and carbonate contents have specific effects on the partitioning of several trace metals, particularly Cd, Cu and Zn. Our results indicated that the relative distributions of metals among geochemical fractions varied in the effluent receiving waters where organic carbon and Fe oxides appeared as the most important parameters. This could therefore decrease the exposure for aquatic organisms that are exposed to those contaminated sediments as well as the risk to human health.     

Biological fluxes conversion and SXRF experiment with a new active biomonitoring tool for atmospheric metals and trace element deposition

A new active biomonitoring tool, keeping alive mosses for 2 months, had demonstrated the buffering action of the water presence on the biological activity of three moss species (chlorophyll fluorescence induction method on Pleurozium schreberi, Scleropodium purum, Eurhynchium praelongum). The two more resistant mosses were exposed on four different sites with parallel exposure of monthly bulk collectors during three successive periods of 2 months. The coarse and sedimentable particles of bulk collectors were separated into different size classes (> 1 mm; 1000-200 microm; 200-40 microm; 40-20 microm). Dry depositions and mosses were analysed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for a stock (microg g(-1)- fluxes (microg m(-2) t(-1)) conversion. The "moss plate" allowed relative site (Ba, Cs, Sb, Sr, U) and species (Pb, Sb, Ti, V) comparisons. Two months were enough for a significant enrichment (Ba, Cd, Pb, Sb, Ti, U, V). Good explicative models were elaborated for Ba, Pb, Sb and Ti (r2 > 70%) including categorical (sites, moss species) and quantitative variables (fluxes of particles size classes). Entire and intact shoots of Scleropodium purum were analysed by detected synchrotron radiation induced X-ray fluorescence (SXRF). The in vivo distribution of the multi-elemental short term enrichment along the moss stem was mainly localized in the plant older parts (Pb, Ti, Cl, Se).     

Exposure of juvenile Danio rerio to aged TiO2 nanomaterial from sunscreen

The toxicity of dietary exposure to artificially aged TiO₂ nanomaterial (T-Lite?) used in sunscreen cream was studied on Danio rerio. Embryolarval assays were conducted to assess the effects of TiO₂ residues of nanomaterial (RNM) on fish early life stages. Juvenile fishes were exposed by the trophic route in two experiments. During the first experiment, juvenile fishes were exposed to TiO₂ RNM for 14 days by adding RNM to commercial fish food. The second one consisted in producing a trophic food chain. Pseudokirchneriella subcapitata algae, previously contaminated with TiO₂ RNM in growth medium, was used to feed Daphnia magna neonates over a 48-h period. Daphnia were used next to feed juvenile fishes for 7 days. Accumulation of Ti, life traits (survival and growth) and biochemical parameters such as energy reserves, digestive (trypsin, esterase, cellulose and amylase) and antioxidant (superoxide dismutase and catalase) enzyme activity were measured at the end of exposures. As expected in the receiving aquatic system, TiO₂ RNM at low concentrations caused a low impact on juvenile zebrafish. A slight impact on the early life stage of zebrafish with premature hatching was observed, and this effect appeared mainly indirect, due to possible embryo hypoxia. When juvenile fish are exposed to contaminated food, digestive enzyme activity indicated a negative effect of TiO₂ RNM. Digestive physiology was altered after 14 days of exposure and seemed to be an indirect target of TiO₂ RNM when provided by food.     

Time‐based differences in the effects of positive and negative affectivity on perceived supervisor support and organizational commitment among newcomers

Building on the broaden‐and‐build theory and research on the negativity bias, this study examines how trait affectivity, as a stable predisposition predicting the pattern of emotional responding, shapes newcomers' perceptions of supervisor support and experience of organizational commitment. Using latent growth modeling and data collected at four points in time from newcomers (N = 158), we found the initial level of perceived supervisor support to mediate a negative relationship between negative affectivity and the level of commitment. Moreover, although newcomers experienced a general decrease in perceived supervisor support and a related decrease in commitment, those with high positive affectivity experienced a weaker decrease in perceived supervisor support, which led to a weaker decrease in commitment. Incidentally, positive affectivity was also positively related to the initial level of commitment. Two post hoc studies indicated that positive and negative affectivity exerted their effects controlling for state affect and replicated the relationship between change in perceived support and commitment. We discuss how these findings inform our understanding of trait affectivity's influence on newcomers' work attitudes.     

Contamination of Clams with Human Norovirus and a Novel Hepatitis A Virus in Cameroon

Food and Environmental Virology - Shellfish constitute an important protein source but may be contaminated by viruses from various origins. A study performed on clams collected in Cameroon showed a...     

Water reuse in tannery beamhouse process

In tanneries, the phases of conditioning and preparing the hide for tanning, as well as the transportation and fixation of tanning substances, are all carried out in aqueous media. Most of the steps of these processes are carried out with fresh water, which is used as a vehicle for the diffusion of chemical products and the extraction of undesirable materials from the hide. The objective of this study is to provide the minimization of water consumption at tanneries by applying the reuse of water at some stages of the process. Alternatives for water reuse were evaluated through analysis of the process wastewater to determine the concentration of some contaminant parameters. In tests with half-hides, the possibility of reusing the liquors from the 2nd bating washing in the 1st bating washing, and of reusing the liquors from the pre-deliming washing in the pre-deliming operation, was verified. In industrial scale the water reuse from a mixture of bating washings in the deliming and deliming bating was tested successfully. The quality of wet-blue leather analyzed in the systems with and without water reuse did not show any considerable differences and satisfies the tannery specifications. Finally, a mathematical program for mass integration was applied to solve the problem of water reuse in the beamhouse steps.     

A study of the relationships between compensation package,work motivation and job satisfaction

This study applied the theoretical framework based on expectancy and discrepancy theories to examine how the elements of total compensation might influence work motivation and job satisfaction. The principal dimensions of total compensation that give rise to distinct reactions among employees were examined. Two samples of employees, 269 exempt employees and 297 nonexempt employees, were studied separately in order to identify the differences of reaction between these two groups. The relationships between the elements of total compensation, work motivation and job satisfaction were analysed by a structural equations model with LISREL VII. Proposals were developed to predict the conditions of compensation efficiency on work motivation and job satisfaction in the cultural context of employment in France. The three principal conclusions of the study were: (1) under certain conditions, individualized compensation of exempt employees can be a factor of work motivation; (2) flexible pay of nonexempt employees neither motivates nor increases job satisfaction; (3) benefits of exempt and nonexempt employees neither motivate nor increase job satisfaction. Copyright © 1999 John Wiley & Sons, Ltd.     

Immunocompetence analysis of the aquatic snail Lymnaea stagnalis exposed to urban wastewaters

Environmental Science and Pollution Research - Wastewater treatment plant effluents from urban area are a well-known source of chronic multiple micropollution to the downstream living organisms. In...     

Occurrence of currently used pesticides in ambient air of Centre Region (France)

Ambient air samples were collected, from 2006 to 2008 at three rural and two urban sites in Centre Region (France) and analyzed for 56 currently used pesticides (CUPs), of which 41 were detected. The four CUPs most frequently detected were the herbicides trifluralin, acetochlor and pendimethalin and the fungicide chlorothalonil, which were found with frequencies ranging between 52 and 78%, and with average concentrations of 1.93, 1.32, 1.84 and 12.15 ng m^?3, respectively. Among the detected pesticides, concentrations of eight fungicides (spiroxamine, fenpropimorph, cyprodinil, tolyfluanid, epoxiconazole, vinchlozolin, fluazinam, fludioxinil), two insecticides (propargite, ethoprophos), and one herbicide (oxyfluorfen) are, to our knowledge, reported for the first time in the literature.The majority of the CUPs showed a seasonal trend, with most of the detections and the highest concentrations occurring during the spring and early summer. The most important pesticides detected were related to arable crops and fruit orchards, the main cultures in this region, highlighting the fact that the main sources come from local applications. Minor differences were found in the profiles of pesticides within rural areas and between rural and urban areas.     

Publicly available datasets on thallium (Tl) in the environment—a comment on <Emphasis Type="Italic">“Presence of thallium in the environment: sources of contaminations,distribution and monitoring methods”</Emphasis> by Bozena Karbowska,Environ Monit Assess (2016) 188:640 (DOI 10.1007/s10661-016-5647-y)

This comment highlights a whole series of datasets on thallium concentrations in the environment that were overlooked in the recent review by Karbowska, Environmental Monitoring and Assessment, 188, 640, 2016 in this journal. Geochemical surveys carried out over the last few decades all over the world at various scales and using different sampling media have reported the concentration of thallium (and dozens more elements) in tens of thousands of samples. These datasets provide a ‘real-world’ foundation upon which source apportionment investigations can be based, monitoring programs devised and modelling studies designed. Furthermore, this comment also draws attention to two global geochemical mapping initiatives that should be of interest to environmental scientists.