Multiparametric effect: concentration analyses

10.2741/1260 ◽  
2004 ◽  
Vol 9 (1-3) ◽  
pp. 1218 ◽  
Author(s):  
Rakesh Sindhi
Keyword(s):  
Effect Concentration

Effect of Mercury on the Survival of Daphnia Magna

1990 ◽  
Vol 22 (5) ◽  
pp. 241-246 ◽  
Author(s):  
I. Brković-Popović
Keyword(s):  
Life Span ◽  
Daphnia Magna ◽  
Abiotic Factors ◽  
Total Hardness ◽  
Chemical Characteristics ◽  
Effect Concentration ◽  
Test Organisms ◽  
Lethal Time ◽  
Two Temperatures ◽  
Time Required

The median lethal time (LT) for each concentration of mercury was determined on the basis of mortality curves. Toxicity curves (i.e., the median life-span of Daphniamagna, LT 50, versus the concentration of mercury) for four tested conditions are shown. The experiments were carried out using two diluents of different total hardness (46 and 119 mg/l as CaCO3), at two temperatures (20°C and 25°C). A comparison of the LT 50s of the control organisms with the LT 50s of the test organisms at mercury concentrations of 0.0075 and 0.0050 mg. l-1 showed that the chemical characteristics and temperatures of the mediums tested did not affect the range of the ‘no effect' concentration. However, the incipient LC 50, and the time required for its appearance, did depend on the combination of the abiotic factors tested.

scholarly journals Analysis of Spatial Variability of River Bottom Sediment Pollution with Heavy Metals and Assessment of Potential Ecological Hazard for the Warta River, Poland

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 327
Author(s):  
Joanna Jaskuła ◽  
Mariusz Sojka ◽  
Michał Fiedler ◽  
Rafał Wróżyński
Keyword(s):  
Heavy Metals ◽  
Bottom Sediment ◽  
Bottom Sediments ◽  
Risk Index ◽  
Point Sources ◽  
Sediment Pollution ◽  
Sample Collection ◽  
Effect Concentration ◽  
Ecological Hazard ◽  
River Bottom

Pollution of river bottom sediments with heavy metals (HMs) has emerged as a main environmental issue related to intensive anthropopressure on the water environment. In this context, the risk of harmful effects of the HMs presence in the bottom sediments of the Warta River, the third longest river in Poland, has been assessed. The concentrations of Cr, Ni, Cu, Zn, Cd, and Pb in the river bottom sediments collected at 24 sample collection stations along the whole river length have been measured and analyzed. Moreover, in the GIS environment, a method predicting variation of HMs concentrations along the whole river length, not at particular sites, has been proposed. Analysis of the Warta River bottom sediment pollution with heavy metals in terms of the indices: the Geoaccumulation Index (Igeo), Enrichment Factor (EF), Pollution Load Index (PLI), and Metal Pollution Index (MPI), has proved that, in 2016, the pollution was heavier than in 2017. Assessment of the potential toxic effects of HMs accumulated in bottom sediments, made on the basis of Threshold Effect Concentration (TEC), Midpoint Effect Concentration (MEC), and Probable Effect Concentration (PEC) values, and the Toxic Risk Index (TRI), has shown that the ecological hazard in 2017 was much lower. Cluster analysis revealed two main groups of sample collection stations at which bottom sediments showed similar chemical properties. Changes in classification of particular sample collection stations into the two groups analyzed over a period of two subsequent years indicated that the main impact on the concentrations of HMs could have their point sources in urbanized areas and river fluvial process.

scholarly journals Predictive ecological risk assessment of pesticide mixtures in Mediterranean porous aquifers

2018 ◽  
Vol 1 ◽  
Author(s):  
Tiziana Di Lorenzo ◽  
Marco Cifoni ◽  
Barbara Fiasca ◽  
Alessia Di Cioccio ◽  
Diana Galassi
Keyword(s):  
Ecological Risk ◽  
Concentration Addition ◽  
Toxicity Data ◽  
Model Species ◽  
Risk Quotient ◽  
Environmental Concentration ◽  
Pesticide Mixtures ◽  
Abruzzo Region ◽  
Effect Concentration ◽  
Porous Aquifers

The ecological risk assessment (ERA) of chemical substances is based on the premise that the protection of the most sensitive taxon safeguards the overall community. Given the severe scarcity of ecotoxicological data concerning groundwater species, we felt urged to consider epigean model species’ sensitivity data to determine the safe pesticide concentrations for obligate groundwater dwelling species. To this end, we performed the ERA of pesticide mixtures occurring in eleven Mediterranean porous aquifers (Abruzzo region; central Italy). The evaluation was based on data collected between 2010 and 2015 by the environmental protection agency of Abruzzo region (ARTA Abruzzo) and included 42 pesticides and 1953 samples. We applied a step-wise procedure: we used the Measured Environmental Concentration (MEC); we estimated the Predicted No-Effect Concentration (PNEC) and we established the ecological risk as Risk Quotient (RQ) based on the ∑MECi/PNECi ratio following a concentration addition model for mixtures’ toxicity. we used the Measured Environmental Concentration (MEC); we estimated the Predicted No-Effect Concentration (PNEC) and we established the ecological risk as Risk Quotient (RQ) based on the ∑MECi/PNECi ratio following a concentration addition model for mixtures’ toxicity. The PNEC was regarded as the concentration below which a harmful effect will most likely not occur to the groundwater dwelling fauna. The toxicity data used to compute the PNEC values were obtained from the US. EPA ECOTOX database confining the search to epigean crustaceans. Missing toxicity data were estimated by ECOSAR v.1.11. PNEC values were calculated by dividing the lowest short-term L(E)C50 value (that refers to the concentration at which 50% of its maximal effect was observed in test species) by appropriate assessment factors (AF). The AF values were selected according to the difference in the sensitivities of groundwater and epigean crustaceans derived from the available studies. Groundwater crustacean species were generally less sensitive to acute exposure to chemicals than the model species Daphnia magna. However, they were more sensitive than their epigean relatives when the comparisons were made among organisms sharing the same family/order. This result suggests caution when inferring the sensitivity of groundwater species from that of epigean taxa. The ecological risk was scored using a binary ecological classification suggesting that appreciable risk is likely when RQ≥1. Pesticide mixture risks were often driven by a minimum of 2 to 11 compounds in the eleven aquifers of Abruzzo region. However, the risk-drivers (i.e., individual pesticides explaining the largest share of potential effects) differed substantially among the aquifers. The results of this study have been published by Di Lorenzo et al. (2018).

scholarly journals Predicted no-effect concentration (PNEC) and assessment of risk for the fungicide, triadimefon based on reproductive fitness of aquatic organisms

Chemosphere ◽  
2018 ◽  
Vol 207 ◽  
pp. 682-689 ◽  
Author(s):  
Na Liu ◽  
Xiaowei Jin ◽  
Junying Zhou ◽  
Yeyao Wang ◽  
Qi Yang ◽  
...  
Keyword(s):  
Aquatic Organisms ◽  
Reproductive Fitness ◽  
Effect Concentration

scholarly journals Toxicity thresholds of nine herbicides to coral symbionts (Symbiodiniaceae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Magena Marzonie ◽  
Florita Flores ◽  
Nora Sadoun ◽  
Marie C. Thomas ◽  
Anais Valada-Mennuni ◽  
...  
Keyword(s):  
Specific Growth ◽  
Tropical Species ◽  
Biologically Relevant ◽  
Guideline Values ◽  
The Family ◽  
Effect Concentration ◽  
Quality Guideline ◽  
Current Water ◽  
Endosymbiotic Algae ◽  
Water Quality Guideline

AbstractOver 30 herbicides have been detected in catchments and waters of the Great Barrier Reef (GBR) and their toxicity to key tropical species, including the coral endosymbiotic algae Symbiodiniaceae, is not generally considered in current water quality guideline values (WQGVs). Mutualistic symbionts of the family Symbiodiniaceae are essential for the survival of scleractinian corals. We tested the effects of nine GBR-relevant herbicides on photosynthetic efficiency (ΔF/Fm′) and specific growth rate (SGR) over 14 days of cultured coral endosymbiont Cladocopium goreaui (formerly Symbiodinium clade C1). All seven Photosystem II (PSII) herbicides tested inhibited ΔF/Fm′ and SGR, with toxicity thresholds for SGR ranging between 2.75 and 320 µg L−1 (no effect concentration) and 2.54–257 µg L−1 (EC10). There was a strong correlation between EC50s for ΔF/Fm′ and SGR for all PSII herbicides indicating that inhibition of ΔF/Fm′ can be considered a biologically relevant toxicity endpoint for PSII herbicides to this species. The non-PSII herbicides haloxyfop and imazapic did not affect ΔF/Fm′ or SGR at the highest concentrations tested. The inclusion of this toxicity data for Symbiodiniaceae will contribute to improving WQGVs to adequately inform risk assessments and the management of herbicides in tropical marine ecosystems.

Assessing the Relative Toxicity of Different Road Salts and Effect of Temperature on Salinity Toxicity: LCx Values vs. No Effect Concentration (NEC) Values

2021 ◽  
Author(s):  
Benjamin John Gray Moulding
Keyword(s):  
Logistic Model ◽  
Effect Of Temperature ◽  
Relative Toxicity ◽  
Test Species ◽  
Ski Resort ◽  
Deicing Salts ◽  
Effect Concentration ◽  
Freshwater Biota ◽  
Different Temperatures ◽  
Alpine Streams

Abstract Freshwater biota are at risk globally from increasing salinity, including increases from deicing salts in cold regions. A variety of metrics of toxicity are used when estimating the toxicity of substances and comparing the toxicity between substances. However, the implications of using different metrics is not widely appreciated. Using the mayfly Colobruscoides giganteus (Ephemeroptera: Colobruscoidea) we compare the toxicity of seven different salts where toxicity was estimated using two metrics 1) the no effect concentrations (NEC) and 2) the lethal concentrations for 10, 25 and 50% of the test populations (LCx). The LCx values were estimated using two different models, the classic log-logistic model and the newer toxicokinetic-toxicodynamic (TKTD) model. We also compare the toxicity of two salts (NaCl and CaCl2) for C. giganteus at water temperatures of 4°C, 7°C and 15°C using the same metrics of toxicity. Our motivation for using a mayfly to assess salinity toxicity was because mayflies are generally salt sensitive, are ecologically important and are common in Australian (sub-)alpine streams. Considering 144-hour LCx values, we found toxicity differed between various salts, i.e., the lowest 144-hour LC50 (8 mS/cm) for a salt used by a ski resort was half that of the highest 144-hour LC50 from artificial marine salts and CaCl2 applied to roads (16mS/cm). 144-hour LC50 results at 7°C showed that analytical grade NaCl was significantly more toxic (7.3mS/cm) compared to analytical grade CaCl2 (12.5mS/cm). Yet for NEC values, there were comparably fewer differences in toxicity between salts and none between the same salts at different temperatures. We conclude that LCx values are better suited to compare difference in toxicity between substances or between the same substance at different test temperatures, while NEC values are better suited to estimating concentrations of substances that have no effect to the test species and endpoint measured under laboratory conditions.

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