The spatial–temporal chemical footprint of pesticides in China from 1999 to 2018

Environmental Science and Pollution Research - The massive use of pesticides brings considerable environmental and human health impacts. This study conducted an overall assessment of the ecological...     

Gathering new knowledge from existing monitoring dataset of Campania marine coastal area (Southern Italy)

Environmental Science and Pollution Research - In this study we propose, a multi-step strategy of selection and characterization of long-term dataset of contaminant concentrations in different...     

Association between biomarkers of exposure to persistent organochlorine compounds (POCs)

Serum concentrations of CB-153 and p,p'-DDE were assessed for 354 men and women from the Swedish Fishermen's Families Cohort, and were found to correlate very well (Pearson's r=0.72). In this particular cohort the main source of exposure to persistent organochlorine compounds are consumption of contaminated fatty fish. High correlations between total PCB/CB-153 and p,p'-DDE have also been found in other population with similar exposure, but not in populations whose major source of exposure to persistent organochlorine compounds is not necessarily through the consumption of contaminated sea food. The authors suggest that when investigating a possible relation between exposure to persistent organochlorine compounds and different health outcomes in populations with exposure similar to the Swedish Fishermen's Families Cohort, there may be no need to analyze more than either CB-153 or p,p'-DDE.     

Exposure to polychlorinated biphenyls in residents near a chemical factory in Italy: the food chain as main source of contamination

High levels of PCBs were recently found in soil, food and some farmers living close to a chemical factory which until the 1980s had produced polychlorinated biphenyls (PCBs) in Brescia, North Italy. We performed a survey on a random sample of subjects aged 20-79 years living in various areas of the town with different levels of soil pollution to investigate factors associated with increased levels of PCB in serum (24 congeners were tested). Total PCB values were closely related to age (Spearman r=0.68; p<0.0001). The 166 consumers of locally produced food had higher PCB levels than non-consumers (median=1143 versus 719; 95th centile=9301 versus 2635ng/g lipid) with the highest levels among consumers of food produced in the most contaminated area close to the factory (median=2551; 95th centile=33464ng/g lipid). A dose-effect relationship between consumption of food produced in this area and PCB blood levels was observed (Spearman r=0.52, p=0.0014). Consumers of only plant food produced in this area had higher levels of PCB than non-consumers (median=1100; 95th centile=10,800ng/g lipid). Three subjects who had worked at the factory in the past showed high PCB levels. Distribution of PCB congeners did not differ between consumers of locally produced food and non-consumers, apart from PCB 209 which was found at high levels in former factory workers and was more common among consumers of food produced in the polluted area. In conclusion, we found high serum PCB levels in humans living in a highly polluted area in an industrialized town in Italy, due mainly to consumption of food produced in polluted areas.     

Uptake and toxicity of Cr(III) in celery seedlings

The present study shows that in celery Cr(III) induces deleterious effects on seedling development and morphology, and a number of metabolic responses related to stress. Exogenous CrCl3 from 0.01 to 1 mM increasingly inhibited seed germination and hypocotyl elongation, or completely blocked it (10 mM), while the root apparatus was dramatically damaged even at the lowest dose. Seedlings took up exogenous Cr(III) in a dose-dependent manner, roots being the site of major metal accumulation; translocation towards the hypocotyl and cotyledonary leaves was also detected. Either total or chlorophyll a content was significantly reduced by chromium as low as 0.01 mM. A large accumulation of free and, to a lesser extent, conjugated polyamines occurred in all segments of treated plants. A dose-dependent relationship linking actual amounts of Cr(III) recovered in the entire seedling or organ and the respective polyamine titre was evidenced. Free putrescine, in particular, was the polyamine exhibiting the highest rate of increase, and cotyledonary leaves the organ where the major response occurred. A marked increase in ubiquitin-protein conjugates after Cr(III) treatment was also observed, particularly in roots. Thus, the study suggests for the first time a possible relationship between ubiquitination and Cr(III)-stress. The putative function of polyamines as a stress response, and the recruitment of the ubiquitin pathway to remove damaged or aberrant proteins which might have been produced in metal-treated seedlings are discussed.     

The effect of a biofilm on solute diffusion in fractured porous media

At sites in fractured rock where contamination has been exposed to the rock matrix for extended periods of time, the amount of contaminant mass residing in the matrix can be considerable. Even though it may be possible to diminish concentrations by the advection of clean water through the fracture features, back diffusion from mass held in the matrix will lead to a continuing source of contamination. In such an event, the development of a biofilm (a thin film of microbial mass) on the wall of the fractures may act to limit or prevent the back diffusion process. The objective of this preliminary study is to explore the influence imparted by the presence of a biofilm on the process of matrix diffusion. The investigation was conducted using radial diffusion cells constructed from rock core in which biofilm growth was stimulated in a central reservoir. Once biofilms were developed, forward diffusion experiments were conducted in which a conservative solute migrated from the central reservoir into the intact rock sample. Diffusion experiments were performed in a total of 11 diffusion cell pairs where biofilm growth was stimulated in one member of the pair and inhibited in the other. The effect of the presence of a biofilm on tracer diffusion was determined by comparison of the diffusion curves produced by each cell pair. A semi-analytical model that accounts for the presence of a biofilm was used to investigate the effect of the biofilm on mass transfer due to changes in the effective porosity, effective diffusion coefficient, and the depth of penetration of the biofilm into the intact rock. The results show that the biofilm acted to plug the rock matrix, rather than forming a discrete layer on the reservoir surface. The reduction in effective porosity due to the biofilm ranged from 6% to 52% with the majority of the samples in the 30% to 50% range. Based on the present results, with more efficient biofilm stimulation, it is reasonable to assume that a more complete plugging of the microcrack porosity might be possible, leaving a much thicker and efficient barrier than could be achieved via a surface biofilm.     

Source determination of highly chlorinated biphenyl isomers in pine needles - comparison to several PCB preparations

The isomer specific composition of 13 technical PCB formulations of different origin and of pine needles was analyzed using GC/MS and HRGC/HRMS. Nonachlorinated biphenyls were identified in 11 among 13 formulations analyzed, with the highest abundance found for highly chlorinated ones (Aroclors 1268 and 1260, Chlorofen, Sovol, Kanechlors 600 and 500, Delor 106, Clophen A60). Decachlorobiphenyl was identified only in Aroclor 1268, Clophen A60, Aroclor 1260 and Chlorofen, comprising, respectively, 8.9, 2.8, 1.3 and 0.82% of the total bulk of nona- and decaCBs detected. Nona- and decaCB were detected in pine needles in Poland with the highest concentrations found at the sites neighboring to a former production sites of the Polish PCB formulations, while in pine needles collected around the Tokyo Bay nona- and decacCB were detected only in four of 10 sites and the concentrations corresponded to those found at the rural areas of Poland.     

Changing contaminant mobility in a dredged canal sediment during a three-year phytoremediation trial

Metal mobility and degradation of organic pollutants were investigated in a contaminated canal sediment in NW England. Sediment was dredged and exposed above the water surface, planted with multiple taxa of Salix, Populus and Alnus and monitored over 32 months. Short-term metal fractionation and phytotoxicity during sediment oxidation were also evaluated in separate laboratory studies. Zinc and Pb redistributed into more mobile fractions, which increased toxicity of the sediment to plants in the laboratory. In contrast, at the canal site, mobility of most elements decreased and total concentrations of Zn, Pb, Cu and Cd fell. Petroleum hydrocarbon concentrations decreased, but the tree-planted treatments appeared less effective at reducing PAH concentrations than treatments colonised by invasive plants. Tree survivorship decreased over time, suggesting increasing phytotoxicity of the exposed sediment in the longer term. Trees provided little benefit in terms of sediment remediation. Options for future management of the sediment are evaluated.     

First fossil evidence of an “interglacial refugium” in the Pyrenean region

A refugium is generally understood as an area where temperate species survive cold periods, such as the Iberian, Italian, or Balkan Peninsulas in Europe. Strictly speaking, this definition refers to what is known as a glacial refugium. However, there are various types of lesser-known refugia such as the interglacial refugium, which denotes a mountainous region at low latitudes, such as the Pyrenees, where species adapted to the cold survive during interstadial periods. The small-vertebrate association from the sequence of Cova Colomera, which is located on the southern face of the Pyrenees and contains the final cold spell of the Late Pleistocene and the beginnings of the temperate period in which we currently find ourselves (the Holocene), could constitute the first fossil evidence of such an interglacial refugium, thus providing new paleoecological data on the phenomenon.