Titanium Dioxide Nanoparticles are Toxic for the Freshwater Mussel Unio ravoisieri: Evidence from a Multimarker Approach

The current work investigated the ecotoxicological effects induced by Titanium Dioxide (TiO2) nanoparticles (NPs), used at three different concentrations (C1 = 10 μg·L−1, C2 = 100 μg·L−1 and C3 = 1000 μg·L−1) in a laboratory experiment, on the freshwater mussel Unio ravoisieri. Biochemical analyses of gills and digestive glands revealed a stress-related disruption of the antioxidant system. The catalase activity and the rates of malonedialdehyde and hydrogen peroxide production were significantly higher in both organs following the exposure to TiO2 NPs and was concentration-dependent. In addition, based on the observed changes in acetylcholinesterase activity, it can be concluded that the disturbance threshold for the cholinergic system was less than 1 mg·L−1 of TiO2. Overall, the results suggest that the mussel Unio ravoisieri could be used as a sentinel species in monitoring surveys assessing the environmental impact of metallic nanoparticles in freshwater systems.

Identification of sentinel plant species for evaluating phytotoxicity of veterinary antibiotics in mediterranean europe

Background Antibiotics used to treat livestock species enter agricultural fields when they are excreted by grazing animals or are present in manure that is added to fields as fertiliser. In the European Union, the potential effects of such antibiotics on terrestrial plants must be evaluated following the standardised OECD 208 method, which specifies the crop and wild species that should serve as “sentinels” for assessing antibiotic exposure. The present study aimed to compare this approved list of sentinel species against crop and wild plant species actually present in agricultural and pasture lands in Mediterranean Europe in order to identify the most appropriate sentinel plants for the region. The study focused on Spain as a region representative of Mediterranean Europe. Georeferenced layers for wild plant species and cultivated areas (crops), livestock density and land cover were combined, and then selection criteria were applied, leading to the identification of sentinel crop species for agriculture and pasture scenarios. Results In the agriculture scenario, the sentinel crop species were barley, wheat, corn, sunflower, dried pie, alfalfa, vetch, oilseed rape and sugar beet; the sentinel wild species were Papaver rhoeas, Galium aparine and Chenopodium album. In the pasture scenario, sentinel wild species were Bromus tectorum, Agrostis capillaris, Trifolium pratense, Lotus corniculatus and Galium aparine. The following common weed species in field boundaries or in pasture lands also emerged as potential sentinel species for risk assessment, even though they are not listed in the OECD 208 method: Sonchus oleraceus, Avena sterilis, Dactylis glomerata, Hordeun murinum and Lolium rigidum. Conclusions The sentinel species identified in this study may be useful in risk assessment procedures covering Mediterranean Europe. The method developed for this study could be useful for identifying sentinel species for other geographical areas.

The composition of mixed-species flocks of birds in and around Chitwan National Park, Nepal

Background Mixed-species flocks (MSFs) have been well sampled in the South Asia, but there has been as yet surprisingly little work on MSFs of Nepal, despite a diverse and well-studied avifauna. We surveyed MSFs in two forest types in and around the Important Bird Area of Chitwan National Park in Nepal, between 150 and 800 m a.s.l., to provide a first description of the composition of MSFs in this area. We also aimed to understand which species should be considered ‘nuclear species’, important to forming MSFs or leading them forward. Results In total, we collected records on 222 MSFs that included 100 species, and 6097 individuals. The MSFs were similar to worldwide patterns in being dominated by leaf-gleaning, non-terrestrial insectivores. However, the MSFs were more dominated by canopy species than usual, and did not have a clear gregarious, understory leading species. Rather drongos (Family Dicruridae) and minivets (Family Campephagidae, Genus Pericrocotus) acted as leaders, and a cluster analysis of composition showed one group of large body size MSFs particularly characterized by the presence of the Greater Racket-tailed Drongo (Dicrurus paradiseus). Conclusions Drongos are known to provide both costs and benefits to other flock participants: they are aggressive birds that can steal food, and manipulate other species with their vocalizations, but at the same time they are ‘sentinel species’ that produce information about predation risk other species can use. This study demonstrates that drongos can be considered nuclear species for some types of MSFs, despite the potential costs of their presence. MSFs led by sentinel species thus may form in Asia, as well as in the Neotropics.

Development of a Fish-Based Multimetric Index for the Assessment of Lagoons’ Ecological Quality in Northern Greece

Maintaining and improving the aquatic ecosystems in the community is the aim of the Water Framework Directive (WFD) 2000/60/EC. The WFD requires the water quality to be classified into five categories. Lagoons are dynamic ecosystems. The fish communities inhabiting them are highly affected by the environmental conditions prevailing both in the freshwater systems and in the marine environment. The current paper presented the first effort to develop a fish-based index (Lagoon Fish-based Index—LFI) for the assessment of the Mediterranean shallow lagoons, as almost all indices produced to date refer to freshwater or estuarine systems. For the development and calibration of the index, data were collected from nine lagoons situated in three estuarine systems in the East Macedonia and Thrace regions. The development of the LFI was based on the principles of the Indices of Biological Integrity (IBIs) that were primary used for the assessment of aquatic ecosystems in the USA. A total number of 25 metrics were selected as potential metrics for the LFI. These metrics describe attributes such as the abundance and composition of the fish fauna, the feeding strategies of the species, and the presence of sentinel species. Finally, eight metrics were included in the LFI.

Mercury levels in Tarmat Contaminated Beaches and its Marine Organisms living along the Qatari Coasts

One of the pollutants that affects the coastal environment of Qatar is the vast expanse of oil residue ‘tarmats’ deposited on its beaches. The current study is aimed at gauging the concentration levels of total mercury (THg) in tarmat contaminated sediments and test their presence in selected coastal species. Three biota classes (Gastropoda, Bivalvia, and Crustacea) have been found on the tarmat of Ras Rakan and Umm Tais islands. Layers of hard asphalt-like tarmats and sediments samples were collected from 34 sites, along the coast of Qatar. Moreover, the Biota Sediment Accumulation Factor (BSAF) was calculated for THg through sentinel species. The mean concentrations of THg is 0.089 ± 0.02 μg.g-1. Compared to earlier studies, a relatively higher concentration of THg (0.463 μg.g-1) had been observed.

A Study Design For The Assessment Of Fish Tumour Prevalence In The Lower St. Clair River

A conclusive fish tumour prevalence assessment has never been conducted in the lower part of the St. Clair River Area of Concern, despite possible re-contamination of the river and anecdotal evidence of fish abnormalities. This paper provides a study design for a comprehensive fish tumour prevalence assessment of the Lower St. Clair River with special focus on Walpole Island First Nation and surrounding waters. Study details such as area of focus, sentinel species, suggested sampling locations, sample size, field protocols and statistical methods are identified. A brief guide for histopathological examination and interpretation is provided. An alternate method of sampling location siting is suggested. This study design is intended to provide a guide and background reference for the implementation of a future full scale fish tumour assessment in the Lower St. Clair River.

A Study Design For The Assessment Of Fish Tumour Prevalence In The Lower St. Clair River

A conclusive fish tumour prevalence assessment has never been conducted in the lower part of the St. Clair River Area of Concern, despite possible re-contamination of the river and anecdotal evidence of fish abnormalities. This paper provides a study design for a comprehensive fish tumour prevalence assessment of the Lower St. Clair River with special focus on Walpole Island First Nation and surrounding waters. Study details such as area of focus, sentinel species, suggested sampling locations, sample size, field protocols and statistical methods are identified. A brief guide for histopathological examination and interpretation is provided. An alternate method of sampling location siting is suggested. This study design is intended to provide a guide and background reference for the implementation of a future full scale fish tumour assessment in the Lower St. Clair River.