The reuse of reclaimed water for irrigation around the Mediterranean Rim: a step towards a more virtuous cycle?

Regional Environmental Change - Climate change and a growing population around the Mediterranean Rim are increasing the need for water and, consequently, the pressure on resources in terms of both...     

What is the best biomarker to assess arsenic exposure via drinking water?

Arsenic (As) is a ubiquitous element. The current WHO guideline for As in drinking water is 10 μg/L. Furthermore, about 130 million people have only access to drinking water containing more than 10 gAs/L. Although numerous studies have shown the related adverse effects of As, sensitive appropriate biomarkers are still required for studies of environmental epidemiology. A review of the literature has shown that various biomarkers are used for such research. Their limits and advantages are highlighted in this paper: (i) the detection of As or its derivatives in the blood is an indication of the dose ingested but it is not evidence of chronic intoxication. (ii) The detection of As in urine is an indispensible procedure because it is a good marker for internal dose. It has been demonstrated to correlate well for a number of chronic effects related to As levels in drinking water. However confounding factors must be taken into account to avoid misinterpretation and this may require As speciation. (iii) As in the hair and nails reflects the level of long term exposure but it is difficult to relate the level with the dose ingested. (iv) Some studies showed a correlation between urinary As and urinary and blood porphyrins. However, it is difficult to use only porphyrins as a biomarker in a population survey carried out without doing further studies. (v) Genotoxic effects are based on the characterization of these potential effects. Most studies have detected increases in DNA damage, sister chromatid exchange, micronuclei or chromosomal aberrations in populations exposed to As in drinking water. Micronuclei assay is the technique of choice to follow these populations, because it is sensitive and easy to use.To conclude, whatever epidemiological studies are, the urinary and toenail biomarkers are useful to provide indications of internal dose. Moreover, micronuclei assay can be complementary use as biomarker of early effects.     

Use of commercial plant species in a hydroponic system to treat domestic wastewaters

The objectives in this work were to investigate a conceptual layout for an inexpensive and simple system that would treat primary municipal wastewater to discharge standards. A commercial hydroponic system was adapted for this study and the wastewater was used to irrigate wooly digitalis (Digitalis lanata Ehrh.) and foxglove (Digitalis purpurea L.). These plants are medicinal and produce cardenolide compounds. Influent and effluent samples were collected once a month for six months and analyzed to determine the various parameters relating to water quality. The legal discharge levels for total suspended solids (SS), biochemical oxygen demand (BOD5), and chemical oxygen demand (COD) were reached for the two tested plants after 48 h of wastewater treatment; the removal was 82, 93, and 79%, respectively, for wooly digitalis and 92, 92, and 84%, respectively, for foxglove. Similar results were obtained during a 6-mo period although the sewage composition varied widely. The system tended to be unable to remove N and P to concentrations below regulated levels. Compared with the nutrient solution composition, the wastewater was more concentrated in Na+ and Cl- and less in N, K+, and Ca2+. These variations can lead to the decline of wooly digitalis plants. Foxglove developed a significant root system to increase mineral absorption wastewater being used as the unique nutritive source. After 10 wk all the wooly digitalis seedlings were dead. Despite this fact, however, the root system remained in place for a significant time (< 4 mo), thus continuing to filter wastewater and to be used as a bacterial support thus making it possible to have a security period to replace the dead plants.     

A Retrospective Isotopic Study of Spruce Decline in the Vosges Mountains (France)

The objective of this study was to assess the time variation of mineral and water stress levels across the life of a declining, Mg-deficient, spruce stand, in order to clarify the factors that caused the decline. Since 1985, strong soil acidification linked to a large leaching of nitrate and base cations was measured at the study site. In 1994, 5 trees were felled and tree rings were measured and analysed for Ca, Mg, K, Sr, ¹³C¹²C and ⁸⁷Sr/⁸⁶Sr isotopic ratios. Strontium pools and fluxes as well as root Sr isotope ratio in relation to depth were also measured. Wood chemical concentrations and isotope ratios were strongly related to the dominance status of each tree. On average during the study period, the ⁸⁷Sr/⁸⁶Sr ratio of spruce wood decreased. Using a mechanistic model computing long term variations of ⁸⁷Sr/⁸⁶Sr ratio in trees and soils, we reproduced the observed trend by simulating soil acidification – increasing Sr drainage from the whole profile, and particularly from the organic horizon –, and root uptake becoming more superficial with time. Between 1952 and 1976, tree ring ¹³C decreased strongly and continuously, which, in addition to other factors, might be related to an increase in water stress. Thus, a decrease in rooting depth, possibly related to soil acidification, appeared as a possible cause for the long term increase in water stress. The extreme drought event of 1976 appears to have revealed and triggered the decline.     

A process mapping model for calculating indirect costs of workplace accidents

This article follows an earlier one in which four criteria and four bases for the development of an indirect-cost calculation model adapted to the accuracy requirements and time constraints of workplace decision-makers were established. A two-level model for calculating indirect costs using process mapping of the organizational response to a workplace accident is presented. The model is based on data collected in interviews with those employees in charge of occupational health and safety in 10 companies of various sizes in different industry sectors. This model is the first to use process mapping to establish the indirect costs of workplace accidents. The approach allows easy identification of the duration and frequency of actions taken by stakeholders when a workplace accident occurs, facilitates the collection of the information needed to calculate indirect costs and yields a usable, precise result. A simple graphic representation of an organization's accident processes helps the user understand each accident's cost components, allowing the identification and reduction of inefficiencies in the overall process. Impact on Industry: By facilitating data collection and shortening the time needed to assess indirect costs of workplace accidents, this indirect cost calculation tool is better suited for workplace use than those currently available.     

Do feather-degrading bacteria actually degrade feather colour? No significant effects of plumage microbiome modifications on feather colouration in wild great tits

Parasites are known to exert selective pressures on host life history traits since the energy and nutrients needed to mount an immune response are no longer available to invest in other functions. Bird feathers harbour numerous microorganisms, some of which are able to degrade feather keratin (keratinolytic microorganisms) and affect feather integrity and colouration in vitro. Although named “feather-degrading” microorganisms, experimental evidence for their effects on feathers of free-living birds is still lacking. Here, we tested whether (i) keratinolytic microorganisms can degrade feathers in vivo and thus modify the colour of feathers during the nesting period and (ii) whether feather microorganisms have a long-term effect on the investment in colouration of newly moulted feathers. We designed treatments to either favour or inhibit bacterial growth, thus experimentally modifying plumage bacterial communities, in a wild breeding population of great tits (Parus major). Our analyses revealed no significant effects of the treatments on feather colours. Moreover, we found that differences in bacterial exposure during nesting did not significantly affect the colouration of newly moulted feathers. Our results suggest that significant feather degradation obtained during in vitro studies could have led to an overestimation of the potential of keratinolytic microorganisms to shape feather colouration in free-living birds.