scholarly journals The use of ciliated microeukaryotes and zooplankton in ecotoxicological studies: a look into the future

Author(s):  
◽  
Jéssica Andrade Vilas Boas

Aquatic ecosystems have been affected by different human activities (e.g., urbanization, industrial and agricultural activities) and hence, changing the water quality, the process, and function exercised by these environments. The evaluation of water quality through ecotoxicological studies has become an effective tool for understanding the effects of pollutants on biological communities, allowing the measurement of anthropogenic effects on aquatic systems. The use of microeukaryotes ciliates as bioindicators has been identified as a great potential for assessing water quality, however, these organisms are still neglected in ecotoxicological fields being necessary to enlarge the studies with these organisms. Moreover, the interaction effect among more than one environmental stressor (e.g., chemical contaminant, temperature) also needs to be more study due to the complexity of the aquatic ecosystems functioning. In the present study, we demonstrated through three chapters that the microeukaryotes ciliates can be included in the ecotoxicological studies since as long as they are expanded the classical ecotoxicological studies where it is possible to develop standard methods and deepen knowledge. Furthermore, a fourth chapter showed the interaction between more than one environmental stressor could contribute to a biodiversity decline and even, future research should be dedicated to assessing different interactions in the Mediterranean aquatic ecosystems. (Chapter 1) By means of a mini review, and discussed a brief history, the current scenario and pointing out their methodological approaches gaps of the ecotoxicological studies with ciliates. (Chapter 2) Performing a meta-analysis, we assessed the available toxicity data of heavy metals and ciliates. The results showed the tolerance of ciliates to heavy metals varies notably being partly influenced by differences in methodological conditions across studies. Moreover, most ciliates are tolerant to heavy metal pollution than the standard test species used in ecotoxicological risk assessments, i.e., Raphidocelis subcapitata, Daphnia magna, and Onchornyncus mykiss. Finally, this study highlighted the importance of developing standard toxicity test protocols for ciliates, which could lead to a better comprehension of the toxicological impact of heavy metals and other contaminants on ciliate species. (Chapter 3) By means of ecotoxicological tests, this study demonstrated the tolerance of Paramecium caudatum to caffeine. The results showed that this species had higher resistance in the environment. Even, we observed a moderate risk for P. caudatum regarding maximum environmental concentrations of caffeine in surface freshwater being that the global distribution of caffeine and the probability of increasing environmental concentrations highlight the need for more studies to better understand caffeine in aquatic ecosystems and the associated risks. (Chapter 4) Finally, by means of an indoor microcosm experiment, it was demonstrated that the temperature can influence the direct and indirect effects of salinity and pesticides on zooplankton communities in Mediterranean coastal wetlands and highlights vulnerable taxa and ecological responses that are expected to dominate under future global change scenarios.

2021 ◽  
Author(s):  
Huaijie He ◽  
Ling Liu ◽  
Wenming Yan

Abstract Heavy metal and arsenic (As) concentrations in the overlying water of Lake WLSH from 2013-2017 to evaluate the water quality of the lake. Heavy metal and As concentrations in Lake WLSH surface sediment from studies performed between 2009-2017 were analyzed of heavy metal geo-accumulation, potential ecological risk and toxicity data for Lake WLSH surface sediment was performed to allow heavy metal and As pollution of Lake WLSH surface sediment to be described clearly, objectively, and comprehensively. The following four main conclusions were drawn. (1) The water quality index of the overlying water showed a tendency of slight pollution in the lake from 2013 to 2017. (2) Pollution by the heavy metals (Cu, Zn, Pb, Cd, Cr) and As in Lake WLSH should be given increased attention. (3) The geoaccumulation indices showed that Cd is the most critical pollutant and that the probabilities of Lake WLSH sediment being slightly polluted and moderately polluted were found to be 72.8% and 11.3%, respectively. (4) Cd is the main contributor (75.2%) to potential ecological risks, and although As is at a low toxicity level, its toxicity-risk contribution is higher than that of other metals (approximately 31%). (5) Positive matrix factorization (PMF) model results indicated that industrial and agricultural resources are the main suppliers of heavy metals to Lake WLSH sediment, contributing 43.2% and 42.6% of the heavy metals and As. The summarized results and conclusions can help the local government further understand heavy metals and As pollution in Lake WLSH and develop corresponding pollution-control measures. This study can also serve as a reference for future research on the heavy metals and As pollution of sediment in Lake WLSH and other lakes.


2020 ◽  
Vol 2020 ◽  
pp. 1-22 ◽  
Author(s):  
Hongyong Xiang ◽  
Qinghua Cai ◽  
Yuan Li ◽  
Zhenxing Zhang ◽  
Lina Cao ◽  
...  

Water is essential for every life living on the planet. However, we are facing a more serious situation such as water pollution since the industrial revolution. Fortunately, many efforts have been done to alleviate/restore water quality in freshwaters. Numerous sensors have been developed to monitor the dynamic change of water quality for ecological, early warning, and protection reasons. In the present review, we briefly introduced the pollution status of two major pollutants, i.e., pesticides and heavy metals, in freshwaters worldwide. Then, we collected data on the sensors applied to detect the two categories of pollutants in freshwaters. Special focuses were given on the sensitivity of sensors indicated by the limit of detection (LOD), sensor types, and applied waterbodies. Our results showed that most of the sensors can be applied for stream and river water. The average LOD was 72.53±12.69 ng/ml (n=180) for all pesticides, which is significantly higher than that for heavy metals (65.36±47.51 ng/ml, n=117). However, the LODs of a considerable part of pesticides and heavy metal sensors were higher than the criterion maximum concentration for aquatic life or the maximum contaminant limit concentration for drinking water. For pesticide sensors, the average LODs did not differ among insecticides (63.83±17.42 ng/ml, n=87), herbicides (98.06±23.39 ng/ml, n=71), and fungicides (24.60±14.41 ng/ml, n=22). The LODs that differed among sensor types with biosensors had the highest sensitivity, while electrochemical optical and biooptical sensors showed the lowest sensitivity. The sensitivity of heavy metal sensors varied among heavy metals and sensor types. Most of the sensors were targeted on lead, cadmium, mercury, and copper using electrochemical methods. These results imply that future development of pesticides and heavy metal sensors should (1) enhance the sensitivity to meet the requirements for the protection of aquatic ecosystems and human health and (2) cover more diverse pesticides and heavy metals especially those toxic pollutants that are widely used and frequently been detected in freshwaters (e.g., glyphosate, fungicides, zinc, chromium, and arsenic).


2021 ◽  
Author(s):  
Vivian E. Fleet

The Multispecies Freshwater Biomonitor (MFB) has been identified as a system able to continuously monitor water quality through detection of changes in the movements of biota which may be caused by external stressors. In this study, behavioural changes of Daphnia magna and Hyalella azteca when exposed to tributyltin and atrazine were detected using the MFB. The applicability of the MFB to be used as a monitor of drinking water quality and the usefulness of the organisms in this automated system was determined. Neither contaminant brought about behavioural changes in either organism that were detectable by the MFB. While extensive literature indicated that this system was useful for field applications, this study concluded that the MFB is not yet able to detect contaminants entering a water system using the above test species. Future research is required to examine other species' ability to detect aquatic contaminants and the ability of the MFB to detect such responses.


2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Ya-jun Hong ◽  
Wei Liao ◽  
Zhen-fei Yan ◽  
Ying-chen Bai ◽  
Cheng-lian Feng ◽  
...  

Water quality criteria are the scientific basis for formulating water quality standards and environmental management practices. Due to the development of urbanization and industrialization, the problem of heavy metal pollution has become a serious environmental problem. Heavy metals not only have major impacts on aquatic organisms, but also seriously threaten human health. However, the current environmental criteria refer to the maximum value limitations of environmental factors in environmental media where harmful or detrimental effects are not produced on specific protected objects. This study reviewed the sources, hazard levels, toxic effect mechanisms, and the current research status of China’s water quality criteria for heavy metal pollutants. In addition, the focus and direction of future research on the toxic effects of heavy metal on aquatic organisms and the necessary criteria changes were discussed. The present study would provide an important theoretical basis for the future research of water quality criteria and risk assessment of heavy metal pollutants.


2021 ◽  
Author(s):  
Vivian E. Fleet

The Multispecies Freshwater Biomonitor (MFB) has been identified as a system able to continuously monitor water quality through detection of changes in the movements of biota which may be caused by external stressors. In this study, behavioural changes of Daphnia magna and Hyalella azteca when exposed to tributyltin and atrazine were detected using the MFB. The applicability of the MFB to be used as a monitor of drinking water quality and the usefulness of the organisms in this automated system was determined. Neither contaminant brought about behavioural changes in either organism that were detectable by the MFB. While extensive literature indicated that this system was useful for field applications, this study concluded that the MFB is not yet able to detect contaminants entering a water system using the above test species. Future research is required to examine other species' ability to detect aquatic contaminants and the ability of the MFB to detect such responses.


2020 ◽  
Vol 82 (10) ◽  
pp. 1995-2006
Author(s):  
Mai Huong ◽  
Dan-Tam Costa ◽  
Bui Van Hoi

Abstract Vietnam, like many developing countries, is facing serious water quality issues due to discharging wastewaters without treatment or with improper treatment, which can constitute a potential risk for aquatic ecosystems, food safety and human health. Hybrid constructed wetlands with four substrate layers (HCW) and modified hybrid constructed wetland (MHCW-1 and MHCW-2) with seven substrate layers were designed to evaluate the enhanced treatment capacity for wastewaters. To this end, we carried out an outdoor experiment at the Vietnam Academy of Science and Technology, Vietnam to treat its wastewaters from April to August 2019. All constructed wetland units were planted with reed Phragmites australis and cyperus Cyperus alternifolius; and specifically wetland MHCW-2 was cultured with earthworm Perionys excavates. Results indicated that MHCW-1 and MHCW-2 with seven substrate layers had higher removal efficiencies of -N, TKN and TP than HCW system. More substrate layers in MHCW-1 and MHCW-2 also resulted in increase of Cu and Pb removal efficiencies, with 73.5%, 79.4%, 71.5% and 67.8%, respectively. Particularly, earthworm addition in MHCW-2 was more efficient in decreasing the concentrations of biochemical oxygen demand (BOD5), with removal efficiency over 70%.


2020 ◽  
Author(s):  
Kurt D Shulver ◽  
Nicholas A Badcock

We report the results of a systematic review and meta-analysis investigating the relationship between perceptual anchoring and dyslexia. Our goal was to assess the direction and degree of effect between perceptual anchoring and reading ability in typical and atypical (dyslexic) readers. We performed a literature search of experiments explicitly assessing perceptual anchoring and reading ability using PsycInfo (Ovid, 1860 to 2020), MEDLINE (Ovid, 1860 to 2019), EMBASE (Ovid, 1883 to 2019), and PubMed for all available years up to June (2020). Our eligibility criteria consisted of English-language articles and, at minimum, one experimental group identified as dyslexic - either by reading assessment at the time, or by previous diagnosis. We assessed for risk of bias using an adapted version of the Newcastle-Ottawa scale. Six studies were included in this review, but only five (n = 280 participants) were included in the meta-analysis (we were unable to access the necessary data for one study).The overall effect was negative, large and statistically significant; g = -0.87, 95% CI [-1.47, 0.27]: a negative effect size indicating less perceptual anchoring in dyslexic versus non-dyslexic groups. Visual assessment of funnel plot and Egger’s test suggest minimal bias but with significant heterogeneity; Q (4) = 9.70, PI (prediction interval) [-2.32, -0.58]. The primary limitation of the current review is the small number of included studies. We discuss methodological limitations, such as limited power, and how future research may redress these concerns. The variability of effect sizes appears consistent with the inherent variability within subtypes of dyslexia. This level of dispersion seems indicative of the how we define cut-off thresholds between typical reading and dyslexia populations, but also the methodological tools we use to investigate individual performance.


2020 ◽  
Author(s):  
Tom Joseph Barry ◽  
David John Hallford ◽  
Keisuke Takano

Decades of research has examined the difficulty that people with psychiatric diagnoses, such as Major Depressive Disorder, Schizophrenia Spectrum Disorders, and Posttraumatic Stress Disorder, have in recalling specific autobiographical memories from events that lasted less than a day. Instead, they seem to retrieve general events that have occurred many times or which occurred over longer periods of time, termed overgeneral memory. We present the first transdiagnostic meta-analysis of memory specificity/overgenerality, and the first meta-regression of proposed causal mechanisms. A keyword search of Embase, PsycARTICLES and PsycINFO databases yielded 74 studies that compared people with and without psychiatric diagnoses on the retrieval of specific (k = 85) or general memories (k = 56). Multi-level meta-analysis confirmed that people with psychiatric diagnoses typically recall fewer specific (g = -0.864, 95% CI[-1.030, -0.698]) and more general (g = .712, 95% CI[0.524, 0.900]) memories than diagnoses-free people. The size of these effects did not differ between diagnostic groups. There were no consistent moderators; effect sizes were not explained by methodological factors such as cue valence, or demographic variables such as participants’ age. There was also no support for the contribution of underlying processes that are thought to be involved in specific/general memory retrieval (e.g., rumination). Our findings confirm that deficits in autobiographical memory retrieval are a transdiagnostic factor associated with a broad range of psychiatric problems, but future research should explore novel causal mechanisms such as encoding deficits and the social processes involved in memory sharing and rehearsal.


2019 ◽  
Author(s):  
Emily L. Dennis ◽  
Karen Caeyenberghs ◽  
Robert F. Asarnow ◽  
Talin Babikian ◽  
Brenda Bartnik-Olson ◽  
...  

Traumatic brain injury (TBI) is a major cause of death and disability in children in both developed and developing nations. Children and adolescents suffer from TBI at a higher rate than the general population; however, research in this population lags behind research in adults. This may be due, in part, to the smaller number of investigators engaged in research with this population and may also be related to changes in safety laws and clinical practice that have altered length of hospital stays, treatment, and access to this population. Specific developmental issues also warrant attention in studies of children, and the ever-changing context of childhood and adolescence may require larger sample sizes than are commonly available to adequately address remaining questions related to TBI. The ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) Pediatric Moderate-Severe TBI (msTBI) group aims to advance research in this area through global collaborative meta-analysis. In this paper we discuss important challenges in pediatric TBI research and opportunities that we believe the ENIGMA Pediatric msTBI group can provide to address them. We conclude with recommendations for future research in this field of study.


1999 ◽  
Vol 39 (2) ◽  
pp. 201-208 ◽  
Author(s):  
C. Dierkes ◽  
W. F. Geiger

Runoff from highways contains significant loads of heavy metals and hydrocarbons. According to German regulations, it should be infiltrated over embankments to support groundwater-recharge. To investigate the decontaminating effect of greened embankments, soil-monoliths from highways with high traffic densities were taken. Soils were analyzed to characterize the contamination in relation to distance and depth for lead, zinc, copper, cadmium, PAH and MOTH. Lysimeters were charged in the field and laboratory with highway runoff to study the effluents under defined conditions. Concentrations of pollutants in roadside soils depend on the age of embankments and traffic density. Highest concentrations were found in the upper 5 cm of the soil and within a distance of up to two metres from the street. Concentrations of most pollutants decreased rapidly with depth and distance. Lead and cadmium could not be detected in lysimeter effluent. Zinc and copper were found in concentrations that did not exceed drinking water quality limits.


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