Plastic microfibers (MF) represent the major source of MF found in the environment, the majority made of polyester (PES). Marine bivalves, suspension feeders widespread in coastal areas subjected to ...higher anthropogenic input, can accumulate MF from the water column in their tissues. This raised some concern about their possible impact on bivalve health and potential transfer along the food chain. In this work, the effects of PES-MF on the mussel Mytilus galloprovincialis were investigated, utilizing MF obtained by cryo-milling of a fleece cover. Fiber characterization indicated the polymer composition as polyethylene terephthalate (PET); the size distribution was in a length range resembling that of MF released from textile washing, and including those that can be ingested by mussels. MF were first screened for short-term in vitro immune responses in mussel hemocytes. The effects of in vivo exposure (96 h, 10 and 100 μg/L, corresponding to about 150 and 1500 MF/mussel/L, respectively), were then evaluated. Data are presented on hemolymph immune biomarkers (Reactive Oxygen Species and nitric oxide production, lysozyme activity), and on antioxidant biomarkers (catalase and glutathione S-transferase) and histopathology in gills and digestive gland. Tissue MF accumulation was also evaluated.
MF exposure stimulated extracellular immune responses both in vitro and in vivo, indicating induction of immune/inflammatory processes. In both tissues, stimulation of antioxidant enzyme activities, suggesting oxidative stress conditions, and histopathological changes were observed, with stronger effects often observed at lower concentration. Although mussel retained a very small fraction of MF, their accumulation was higher in the digestive gland than in gills, and in both tissues of mussels exposed to the lowest concentration. Selective accumulation of shorter MF was also observed, particularly in gills. Overall, the results demonstrate that at environmental exposure levels, PET-MF have a significant impact on mussel physiology, affecting multiple processes in different tissues.
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•Effects of heterogeneous PES MF on the mussel M. galloprovincialis•In vitro MF stimulate immune responses in the hemocytes.•In vivo exposure induced tissue inflammation and oxidative stress.•Histopathological changes in gills and digestive gland•Small but selective accumulation of shorter MFs
Disposal of the vast amounts of tannery waste that are currently generated is a significant problem. Anaerobic treatment of different types of tannery waste (fleshings, skin trimmings and wastewater ...sludge) was investigated. The biochemical methane potential is the same at 37
°C or 55
°C and an assay of this was shown to be an appropriate screening tool with which to estimate the susceptibility of a substrate to anaerobic digestion. The start-up procedure of a tannery waste thermophilic anaerobic digestion in 100
days using seed from mesophilic digester processing municipal sludge is presented. The specific methane production potential at 55
°C is estimated to be 0.617
m
3
kg
−1 of volatile suspended solids for tannery waste sludge, 0.377
m
3
kg
−1 for tannery waste trimmings and 0.649
m
3
kg
−1 for tannery waste fleshings. Additional concerns such as chromium content, salinity and temperature fluctuations were also addressed. Chromium content and salinity showed no adverse effects; however a reactor temperature reduction of 4.4
°C led to a drop in biogas production of 25%, indicating a requirement to keep the temperature constant at 55
°C.
The use of a very effective insecticide against sucking pests, neonicotinoid imidacloprid, has been increasing extensively. For this reason elevated concentrations are expected in aquatic ...environment. Despite this fact, there is still a lack of data available on its possible risk for the environment. In this study, the potential hazards of imidacloprid and its commercial product Confidor SL 200 to aquatic environment were identified by the acute and chronic toxicity assessment using bacteria
Vibrio fischeri, algae
Desmodesmus subspicatus, crustacean
Daphnia magna, fish
Danio rerio and the ready biodegradability determination. We found out, that imidacloprid was not highly toxic to tested organisms in comparison to some other environmental pollutants tested in the same experimental set-up. Among the organisms tested, water flea
D. magna proved to be the most sensitive species after a short-term (48
h EC50
=
56.6
mg
L
−1) and long-term exposure (21
d NOEC
=
1.25
mg
L
−1). On the contrary, the intensified toxicity of Confidor SL 200 in comparison to analytical grade imidacloprid was observed in the case of algae and slight increase of its toxicity was detected testing daphnids and fish. The activities of cholinesterase, catalase and glutathione S-transferase of daphnids were not early biomarkers of exposure to imidacloprid and its commercial product. Imidacloprid was found persistent in water samples and not readily biodegradable in aquatic environment. Due to increased future predicted use of commercial products containing imidacloprid and the findings of this work, we recommend additional toxicity and biodegradability studies of other commercial products with imidacloprid as an active constituent.
Current understanding of how environmental aging of microplastics contributes to their ecotoxicity is low. We investigated whether incubation of microplastics in waters with different organic load ...and toxic potential alters the toxicity of microplastics to crustacean Daphnia magna, fish embryos Danio rerio and plant Lemna minor. Polyethylene primary microplastics; specifically microbeads from facial scrub; were subjected to 3-weeks incubation in low affected spring water, river water, effluent from the municipal wastewater treatment plant (WWTP) and municipal landfill leachate. Primary microplastics had no acute effect on D. magna mobility and D. rerio embryos development. While high organic load wastewaters; WWTP effluent and landfill leachate; showed evident toxicity for D. magna and D. rerio embryos, microplastics aged in these wastewaters had no effect. This suggests that adsorption of pollutants from wastewaters to microplastic particles was not high enough to induce acute toxicity to D. magna and D. rerio. On the contrary, primary microplastics affected the root growth of L. minor. Interestingly, aging of microplastics in low organic-load waters mitigated the toxicity of microplastics for L. minor, while microplastics aged in high-organic load waters had the same adverse effect as primary microplastics. Partly, these effects can be explained by different extent of coating on microplastics in different water samples. This study suggests that aging of microplastics in wastewaters and natural waters did not significantly enhance the toxicity to selected test species, but further studies on plants may be of interest.
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•Coating of aged microplastics in natural waters and wastewaters differs from primary microplastics.•Aged microplastics have different sinking properties.•Aging of microplastics does not increase the toxicity to daphnids, duckweed and zebrafish.•Primary microplastics affect only duckweed root length.•Aging in some waters may mitigate toxic effects of microplastics for roots.
Microplastics aged in wastewaters and natural waters are not more toxic as primary microplastics.
Imidacloprid (IMI) is at the moment the insecticide with the world’s fastest growing sales and is considered possible replacement for the widely used organophosphorus pesticide, diazinon, which is ...subject to phased revocation in many countries. In this study, biochemical, reproductive and survival parameters of the water flea (
Daphnia magna) after chronic exposure to IMI, its commercial liquid formulation Confidor SL 200 and diazinon are presented and compared. According to the lowest observed effect concentrations, diazinon is more toxic to the reproduction of
D. magna than IMI and Confidor SL 200, which exert similar toxicity. The same was observed for the survival, except that Confidor SL 200 is more toxic than IMI. In polluted aquatic environments, the actual levels of diazinon are potentially chronically hazardous to the reproduction of
D. magna (risk quotient
>
1). According to very few measured environmental levels of IMI, the latter is not expected to be chronically hazardous, unless it is accidentally spilled in a small pond. In such case, the predicted concentrations of IMI would present a potential chronic risk to
D. magna, and a potential acute risk to other aquatic invertebrates. In the future, higher environmental levels of IMI are expected due to its increasing use and physico-chemical properties. The literature survey summarized in this work suggests that further ecotoxicological studies with a broader spectrum of aquatic organisms are needed before IMI is classified as safer than currently applied pesticides.
New products of nanotechnologies, including nanoparticles, need to be assessed according to their biological reactivity and toxic potential. Given the large number of diverse nanomaterials, a tiered ...approach is favoured. The aim of our work presented here is to elaborate an
in vivo assay with terrestrial invertebrates (
Porcellio scaber), which could serve as a first step of hazard identification of nanoparticles. We adapted the widely used acridine orange/ethidium bromide (AO/EB) assay to be applicable for cell membrane stability assessment of entire organ where the animal was exposed
in vivo. The digestive glands (hepatopancreas) of terrestrial isopods were taken as a model test system. The assay was validated with Cu(NO
3)
2 and surfactants. The results showed that all tested nanoparticles, i.e. nanosized TiO
2, nanosized ZnO and fullerenes (C
60) have cell membrane destabilization potential. As expected, C
60 is the most biologically potent. The AO/EB
in vivo assay proved to be fast because response is recorded after 30
min of exposure, relatively simple because digestive glands are inspected immediately after isolation from exposed animals and promising approach because different types of nanoparticles could be tested for their biological potential. This assay provides data for the identification of hazardous potential of nanoparticles before subsequent steps in a tiered approach are decided.
Imidacloprid is a neonicotinoid insecticide with neurotoxic action that, as a possible alternative for commonly used organophosphorus pesticides, has gained registration in about 120 countries for ...use in over 140 agricultural crops. Only few data are available on its toxicity for soil invertebrates. We therefore assessed the effects of imidacloprid on survival, weight gain, feeding rate, total protein content, glutathione S-transferase activity (GST), and digestive gland epithelial thickness in juveniles and adults of the terrestrial isopod Porcellio scaber. After two weeks of feeding on imidacloprid-dosed food, weight gain (NOEC 5μg/g dry food) and feeding rate (NOEC 10μg/g) in juveniles, and feeding rate (NOEC<10μg/g) and digestive gland epithelial thickness (NOEC<10μg/g) in adults were most affected. In juveniles induction of GST activity and increase of total protein content per wet animal weight was detected at 5μg/g dry food, whereas in adults a reduction of GST was observed at 25μg/g (NOEC 10μg/g). An estimate of actual intake rates suggests that imidacloprid affects isopods at similar exposure concentrations as insects. The toxicity of imidacloprid was similar to that of the organophosphorus pesticide diazinon, tested earlier using the same methods Stanek, K., Drobne, D., Trebse, P., 2006. Linkage of biomarkers along levels of biological complexity in juvenile and adult diazinon fed terrestrial isopod (Porcellio scaber, Isopoda, Crustacea). Chemosphere 64, 1745–1752. At actual environmental concentrations, diazinon poses a higher risk to P. scaber. Due to its increasing use in crop protection and higher persistence in soil, imidacloprid might however, be potentially more dangerous after long-term application. We conclude that toxicity testing with P. scaber provides relevant, repeatable, reproducible and comparable toxicity data that is useful for the risk assessment of pesticides in the terrestrial environment.
A single-species laboratory test with terrestrial invertebrates was used to identify the hazard of nanosized TiO sub(2). Feeding parameters, weight change, mortality, and the activities of catalase ...and glutathione-S-transferase were evaluated after 3 or 14 days of dietary exposure. The effects of nano-TiO sub(2) were dependent on exposure concentration and duration, total consumed quantity, size and pre-treatment of particles. The intensity of a response was ruled by duration of exposure and not by consumed quantity of nano-TiO sub(2) or exposure concentration as expected. The response to nano-TiO sub(2) is described as threshold-like. The exposure concentrations 10-1000kg TiO sub(2)/g dry food (1.35-1025kg of total consumed quantity of TiO sub(2)/g animal wet wt.) were identified as safe for tested species after tested exposure period. We conclude that the response to nanoparticles is different from that of soluble chemicals therefore these two types of data should be interpreted and processed differently.
Hidradenitis Suppurativa Jemec, Gregor B.E
The New England journal of medicine,
01/2012, Volume:
366, Issue:
2
Journal Article
Peer reviewed
Hidradenitis suppurativa, a chronic inflammatory disease of apocrine gland–bearing skin, is characterized by recurrent nodules, sinus tracts, and abscesses. Possible treatment approaches are ...reviewed, as are the few randomized trials and the limitations of available data.
Foreword
This
Journal
feature begins with a case vignette highlighting a common clinical problem. Evidence supporting various strategies is then presented, followed by a review of formal guidelines, when they exist. The article ends with the author's clinical recommendations.
Stage
A 36-year-old woman has recurrent boils under both arms and in the groin. They flare premenstrually, causing pain, suppuration, and an offensive odor. Scarring has developed in the groin area, and chronically draining sinus tracts are interspersed with normal skin. Treatment with short courses of antibiotics or with incision and drainage has had no apparent effect, and she has become socially isolated because of embarrassment about her condition. How would you manage this case?
The Clinical Problem
Hidradenitis suppurativa
1
,
2
is a chronic, recurrent inflammatory disease affecting skin that bears apocrine glands. It usually develops after puberty, manifested as . . .
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