Chromium is a heavy metal used in various industrial sectors. Improper handling and storage of chromium-laden effluents or wastes can lead to the pollution of the environment. The most toxic form is the more mobile one: hexavalent chromium Cr(VI). The reduction of Cr(VI) results in the immobilisation of chromium into its less toxic trivalent form Cr(III). This phenomenon may prevent the contamination of groundwater when the soil in the vadose zone is contaminated. Many bacteria have been isolated from contaminated soils and described to reduce Cr(VI) into Cr(III). A new Cr(VI)-reducing strain, identified as a Streptomyces thermocarboxydus,has been isolated and studied in our laboratories for its ability to reduce Cr(VI). This aerobic bacterium, in contrast to other genera described which mediate reduction via enzymes, produces reducing agents into the culture supernatants. Cr(VI) reduction by these substances is accelerated by the presence of small concentration of cupric ions (Cu2+). The reducing agent(s) can be easily recovered from the bacterial cultures and used as cell-free solution to treat contaminated soils by an in situ or ex situ processes. 相似文献
The brown mussel Perna perna (Linnaeus, 1758) is a valuable resource for aquaculture in tropical and subtropical coastal regions. It presents desirable characteristics for biomonitoring, including being sessile, widely distributed and abundant, and is a filter-feeder able to accumulate several classes of pollutants (e.g., metals, hydrocarbons, among others). Mussels’ biological responses to pollution exposure can be measured as biomarkers, which include alterations ranging from molecular to physiological levels, to estimate the degree of environmental contamination and its effects on biota. This full review compiles two decades (2000–2020) of literature concerning biological effects on P. perna mussel caused by environmental pollutants (i.e., metals, hydrocarbons, and emerging pollutants), considering environmental and farm-based biomonitoring. Biochemical markers related to mussels’ oxidative status were efficient for the biomonitoring of metals (i.e., antioxidant enzymes associated with oxidative damage in biomolecules). Genotoxicity and cytotoxicity indicators (i.e., comet, micronucleus, and neutral red assays) provided a depiction of hydrocarbon contamination. The neutral red assay gave a time-concentration cytotoxic response to a wide range of pollutants, including emerging pollutants (e.g., pharmaceuticals and biocides) and hydrocarbons. Perna perna hemocyte parameters provided a useful approach for biocide biomonitoring. This paper summarizes useful biomarkers from molecular to physiological levels in this mussel species used to identify and quantify the degree of coastal pollution. An integrated biomarker analysis may provide a way to overcome possible biomarker variations and assess multi-polluted sites. Nevertheless, it is necessary to investigate biomarker variations according to natural factors (e.g., season and gonad maturation stage) to standardize them for trustworthy biomonitoring. 相似文献
The present study explores how oil and gas companies use Facebook to communicate about community-supporting initiatives and engage stakeholders. Drawing from the company–cause fit and social interactivity literature, we examined the type of message and the language used in company Facebook posts to elicit stakeholder engagement, as measured by the number of likes, shares, and comments. We content analyzed 953 Facebook posts from 12 companies featured on Oil & Gas Journal’s top 50-company list. The results showed that, although oil and gas companies are posting about their CSR-related efforts on Facebook, their lack of two-way messaging and interactive language use are not effectively engaging stakeholders. In terms of theory, this study advances company–cause fit and interactive studies by applying them to the oil and gas industry. In terms of practice, the results highlight the importance of using diverse messaging and interactive language when utilizing Facebook to engage stakeholders. 相似文献
Environmental Science and Pollution Research - Compared to antibiotic parent molecule, human metabolites are generally more polar and sometimes not less toxic in wastewater. However, most... 相似文献
Regional Environmental Change - Abandoned mines are a recurrent problem for nearby communities in Mediterranean regions because mine tailings represent a major source of polymetallic contamination.... 相似文献
In the current media landscape, organizations often communicate about science directly with publics through online channels rather than relying on journalist gatekeepers. Online platforms present organizations with the opportunity to participate in two-way communication in order to increase engagement with science. The present study examined how the National Oceanic and Atmospheric Administration (NOAA) utilizes social media to interact with publics. Results suggest that NOAA does not fully utilize the dialogic potential of social media, which could enhance both the public’s science literacy and trust in science regarding climate change specifically. This study informs how public relations theory may complement science communication theory and practice as deficit model-thinking transitions to contemporary approaches for public engagement with science. 相似文献
Pharmaceuticals reach terrestrial environments through the application of treated wastewaters and biosolids to agricultural soils. We have investigated the toxicity of 15 common pharmaceuticals, classified as nonsteroidal anti-inflammatory drugs (NSAIDs), blood lipid-lowering agents, β-blockers and antibiotics, in two photosynthetic organisms. Twelve pharmaceuticals caused inhibitory effects on the radicle and hypocotyl elongation of Lactuca sativa seeds. The EC50 values obtained were in the range of 170–5656 mg L−1 in the case of the radicle and 188–4558 mg L−1 for the hypocotyl. Propranolol was the most toxic drug for both root and hypocotyl elongation, followed by the NSAIDs, then gemfibrozil and tetracycline. Other effects, such as root necrosis, inhibition of root growth and curly hairs, were detected. However, even at the highest concentrations tested (3000 mg L−1), seed germination was not affected. NSAIDs decreased the photosynthetic yield of Chlamydomonas reinhardtii, but only salicylic acid showed EC50 values below 1000 mg L−1. The first effects detected at low concentrations, together with the concentrations found in environmental samples, indicate that the use of biosolids and wastewaters containing pharmaceuticals should be regulated and their compositions assessed in order to prevent medium- and long-term impacts on agricultural soils and crops.
Polluted sediments in rivers may be transported by the river to the sea, spread over river banks and tidal marshes or managed,
i.e. actively dredged and disposed of on land. Once sedimented on tidal marshes, alluvial areas or control flood areas, the
polluted sediments enter semi-terrestrial ecosystems or agro-ecosystems and may pose a risk. Disposal of polluted dredged
sediments on land may also lead to certain risks. Up to a few years ago, contaminated dredged sediments were placed in confined
disposal facilities. The European policy encourages sediment valorisation and this will be a technological challenge for the
near future. Currently, contaminated dredged sediments are often not valorisable due to their high content of contaminants
and their consequent hazardous properties. In addition, it is generally admitted that treatment and re-use of heavily contaminated
dredged sediments is not a cost-effective alternative to confined disposal. For contaminated sediments and associated disposal
facilities used in the past, a realistic, low cost, safe, ecologically sound and sustainable management option is required.
In this context, phytoremediation is proposed in the literature as a management option. The aim of this paper is to review
the current knowledge on management, (phyto)remediation and associated risks in the particular case of sediments contaminated
with organic and inorganic pollutants. 相似文献
Surface sediments throughout Ebrié lagoon, Côte d’Ivoire were collected in 2001 and analyzed for their heavy metal and polycyclic aromatic hydrocarbons (PAH) contaminant content. Geochemical maps of heavy metals (Cd, Cu, Zn, Fe, and Mn) in the surface sediment were produced based on geographical information system (GIS) technology. Heavy metals and PAH were detected at high concentration and provide evidence for several anthropogenic inputs to the lagoon. A significant spatial relationship was found for Fe, Zn, and Cu in the sediment using a GIS-based analysis, suggesting that these metal contaminants in the sediments of the Biétri bay had common sources. 相似文献