Hormesis and ecological risk assessment: Fact or fantasy?

Hormesis is a widespread phenomenon across occurring many taxa and chemicals, and, at the single species level, issues regarding the application of hormesis to human health and ecological risk assessment are similar. However, interpreting the significance of hormesis for even a single species in an ecological risk assessment can be complicated by competition with other species, predation effects, etc. In addition, ecological risk assessments may involve communities of hundreds or thousands of species as well as a range of ecological processes. Applying hormetic adjustments to threshold effect levels for chemicals derived from sensitivity distributions for a large number of species is impractical. For ecological risks, chemical stressors are frequently of lessor concern than physical stressors (e.g., habitat alteration) or biological stressors (e.g., introduced species), but the relevance of hormesis to non‐chemical stressors is unclear. Although ecological theories such as the intermediate disturbance hypothesis offer some intriguing similarities between chemical hormesis and hormetic‐like responses resulting from physical disturbances, mechanistic explanations are lacking. While further exploration of the relevance of hormesis to ecological risk assessment is desirable, it is unlikely that hormesis is a critical factor in most ecological risk assessments, given the magnitude of other uncertainties inherent in the process.     

Elemental measurements and health risk assessment of sub-Saharan African medicinal plants used for cardiovascular diseases’ and related risk factors’ treatment

BackgroundDietary factors have been noted to influence the development of cardiovascular diseases (CVDs) which are the number one global cause of death. In this study, the nutritional importance and human health risk of the minerals composition of 20 medicinal plants’ (MPs) parts used for treating CVDs and related risk factors in sub-Saharan Africa (SSA) were assessed.MethodsInductively coupled plasma technology was used for determining the minerals composition of the MPs while human health risk assessment was based on hazard quotients, hazard indexes and non-carcinogenic risk analysis of the studied heavy metals.ResultsThe investigation showed varied level of minerals in the studied MPs’ parts with K having the highest concentration in most. Although level of some elements inM. lucida, V. amygdalina leaves, T. cacao seed and Z. officinale rhizome revealed their possibility in preventing the occurrence of atherosclerosis, unsafe levels of some trace elements were recorded in M. lucida and V. amygdalina leaves. V. amygdalina leaves and A. cepa bulb also had their Pb contents higher than the WHO/FAO Codex permitted maximum level for leafy and bulb vegetables, respectively. In spite of the desirable Na/K and Zn/Cu ratios in all the tested MPs with their Cd and Pb levels below the WHO recommended maximum levels for dried medicinal plant materials, health risk assessment showed that habitual use of almost all of the studied MPs would present an unacceptable risk of non-carcinogenic effects on health. With the exception of S. aromaticum flower bud and T. tetraptera fruit, principal component and hierarchical cluster analyses of other plants’ parts (MPs’ parts aside from the leaves) analysed provided a distinction between MPs which have found food applications and those solely used for medicinal purposes.ConclusionsThe study revealed that type of MP, plants’ part, maturity stage, agricultural practice, growing environment and conditions, are among the factors determining the safety of plant materials used for CVDs’ and related risk factors’ treatment in SSA. To protect the lives of CVDs patients who rely on traditional medicine for treatment, government of SSA countries and relevant authorities need to set a regulatory limit for maximum acceptable concentration of minerals in MPs used in the region. Assessment of the physicochemical properties and pollution level of soil used for cultivation of these MPs is also encouraged.     

Ecological benefits assessment: A policy‐oriented alternative to regional ecological risk assessment

As the focus of many environmental and resource management decisions shifts to larger ecological units such as watersheds and ecoregions, the respective roles of ecological risk and ecological benefits must be reassessed. At larger ecological scales, risk becomes much more difficult to characterize because of the focus on the system rather than individual species. However, quantifying the monetary value of many ecological benefits is also difficult because no direct measures of their value exist, and the indirect techniques used by economists are not fully accepted in some policy‐making settings. This dilemma may be resolved by considering ecological resource/service flows, which are ecological benefits in physical rather than monetary units. By assessing the whole range of resource/service flows and the changes to each that would result from different management/control alternatives, scientists would be able to provide policy‐makers a much better basis for their decisions, and the resulting assessment would characterize changes in ecological features that are more familiar to both policy‐makers and the public.     

Integrating economic input–output life cycle assessment with risk assessment for a screening-level analysis

Goal, Scope, and Background  The paper describes the integration of the economic input–output life cycle assessment (EIO-LCA) model and the environmental fate and transport model (CHEMGL) with a risk assessment tool. Utilizing the EIO-LCA, instead of a traditional LCA, enables a rapid, screening-level analysis of an emerging chemical of concern, decabromodiphenyl ether (DecaBDE). The risk assessment in this study is evaluated based on the mass of chemical released, estimated concentrations, exposure, and chemical toxicity. Methods  The relative risk from ten economic sectors identified within the EIO-LCA model, 55 chemicals utilized in those sectors and DecaBDE along with four potential DecaBDE breakdown products, were evaluated for the life cycle stages and exposure pathways. The relative risk (expressed as toluene equivalents) of the different chemicals, sectors, and life cycle stages were compared to assess those representing the greatest overall relative risks to humans (via inhalation and ingestion) and fish. Results  The greatest overall risk to human health resulted from the manufacturing and production stages. For fish, the manufacturing stage represented virtually all of the risk. Of the 56 chemicals evaluated, DecaBDE represented the majority of the total risk to humans. However, DecaBDE posed the least risk compared to its potential breakdown products. Discussion  The risk to humans from ingestion, which represented the greatest risk, from the production, manufacturing, and consumption stages can be controlled and reduced through various safety precautions in the workplace. Additionally, the increasing concentration of DecaBDE in anaerobic compartments represents a threat to humans and fish via the higher risk DecaBDE breakdown products. Conclusions  Overall, the manufacturing and production life cycle stages pose the greatest risk to humans and fish. The sediment compartment received the highest DecaBDE concentration for the production, manufacturing, and consumption stages. This case study demonstrates that the integrated EIO-LCA with risk assessment is suitable for screening-level analysis of emerging chemicals due to rapid life cycle inventory analysis. Recommendations  The production and manufacturing stages allow for greater industry control and government regulation, compared to the consumption stage, because there are fewer point sources. This integrated life cycle methodology may allow chemical designers to evaluate each stage and assess areas where risks can be minimized.     

Chemistry of Cirsium and Carduus: a role in ecological risk assessment for biological control of weeds?

Prediction of host plant range and ecological impact of exotic phytophagous insects, such as insects for classical biological control of weeds, represents a major challenge. Recently, the flowerhead weevil (Rhinocyllus conicus Fröl.), introduced from Europe into North America to control exotic thistles (Carduus spp.), has become invasive. It feeds heavily on some, but not all species of native North American thistles (Cirsium spp.). We hypothesized that such non-target use among native plants could be better predicted by knowledge of characteristic chemical profiles of secondary compounds to supplement the results of host specificity testing. To evaluate this hypothesis, we reviewed the literature on the chemistry of Cirsium and Carduus thistles. We asked what compounds are known to be present, what is known about their biological activity, and whether such information on chemical profiles would have better predicted realized host range and ecological effects of R. conicus in North America. We found an extensive, but incomplete literature on the chemistry of true thistles. Two main patterns emerged. First, consistent chemical similarities and interesting differences occur among species of thistles. Second, variation occurs in biologically active groups of characteristic compounds, specifically flavonoids, sterols, alkaloids and phenolic acids, that are known to influence host plant acceptance, selection, and feeding by phytophagous insects. Surprisingly, sesquiterpene lactones, which are characterisitic in closely related Asteraceae, have not been extensively reported for Cirsium or Carduus. The minimal evidence on sesquiterpene lactones may reflect extraction methods vs. true absence. In summary, our review suggests further research on thistle chemistry in insect feeding is warranted. Also, since the exotic Canada thistle (Cirsium arvense) is an invasive thistle of current concern in North America, such research on mechanisms underlying host range expansion by exotic insects would be useful.     

The 1991–1992 rapid ecological assessment of Palau’s coral reefs

At the request of the Palau and US governments, a team of 30 scientists under the leadership of the Nature Conservancy completed a rapid ecological assessment (REA) of nearshore marine resources in Palau in 1992. The REA provided ecological input to Palau's ongoing master plan for economic development and identified 45 marine sites worthy of special protection. The REA relied on previous literature, 1992 aerial photography, interviews, and field observations. A combination of qualitative and quantitative techniques were used to assess stony corals, other reef invertebrates, reef and shore fishes, macroscopic algae, seagrasses, sea turtles and other marine organisms. The REA covered a variety of coral reef habitats including beaches, seagrass beds, fringing reefs, lagoons, passes, channels, reef holes, patch and pinnacle reefs, barrier reefs, atolls, submerged reefs, mangroves, and rock islands. Major stresses to Palau's coral reefs include sedimentation from soil erosion, overfishing, and damage from periodic storms and waves. Minor stresses include dredge-and fill activities, sewage pollution, anchor damage, tourism use, ship groundings, aquarium fish collecting, and minor crown-of-thorns (Acanthaster) infestations.     

A physiologically based model of pest–natural enemy interactions

The population dynamic processes in aphids and mites are very similar, because the two groups show strong similarities in their biology. Resource limitation, density-dependent emigration and natural enemies are major factors controlling aphid and mite populations, but an assessment of their relative importance has proven difficult. We used a physiologically based simulation model to investigate the relative impact of the three factors on aphid pest populations. The present simulation model includes winter wheat, three aphid species, Metopolophium dirhodum (Wlk.), Rhopalosiphum padi (L.) and Sitobion avenae (F.) (Hom.: Aphididae) and three parasitoids, Aphelinus abdominalis Dalman (Hym.: Apheliniidae), Aphidius rhopalosiphi De Stefani-Perez and Praon volucre (Hal.) (Hym.: Aphidiidae). We derived and parameterized the model from literature data and validated it against independent field data. The study showed that resource limitation and density-dependent alate production restricts aphid numbers in the field. The mortality due to parasitoids increased late in the season and reduced the peak aphid numbers only moderately. The modelling approach we used is appropriate for simulating other pest–natural enemy systems, such as the spider mite–predatory mite system. Using an object-oriented modelling framework as a template, acarologists can now efficiently develop the simulation model of their choice. This revised version was published online in November 2006 with corrections to the Cover Date.     

Fuzzy rule-based Fine–Kinney risk assessment approach for rail transportation systems

Rail transportation is one of the most crucial public transportation types for big and crowded cities. In rail transportation systems, stakeholders face serious issues involved in workshops, stations, lines and their environments, and general office buildings. In order to reach an increased awareness and better occupational health and safety (OHS) management, a new risk assessment approach is proposed in this study. This approach includes a combination of Fine–Kinney method and a fuzzy rule-based expert system. It captures nonlinear causal relationships between Fine–Kinney parameters. Since there is a high level of vagueness involved in the OHS risk assessment data, the rule-based expert system is developed for probability (P), exposure (E), and consequence (C) for evaluating risk score. A case study is carried out in a rail transportation system in Istanbul/Turkey, and a comparison with the classical Fine–Kinney method is discussed. Results of the case study reveal risk clusters and corresponding control measures that should be taken into consideration. The study methodologically contributes to risk assessment in the knowledge, while case study in a real rail transportation system offers an insight into public transport industry in safety improvement.     

A stochastic model for the spatial distribution of species based on an aggregation–repulsion rule

The heterogeneity associated with the spatial distribution of organisms is an awkward problem in ecology because this heterogeneity directly depends on the sampling scale. To specify the scope of the influence of sampling scale on the level of species aggregation, we need data sets that entail excessive sampling costs in situ. To find a solution for this problem, we can use models to simulate patterns of organisms. These models are often very complex models that take into account heterogeneity of habitats and displacement or longevity of studied species. In this article, we introduce a new stochastic model to simulate patterns for one taxon and we want this model to be parsimonious, i.e., with few parameters and able to simulate observed patterns. This model is based on an aggregation–repulsion rule. This aggregation–repulsion rule is defined by two parameters. On a large scale, the number of aggregates present on the pattern is the first parameter. On a smaller scale, the level of aggregation–repulsion among individuals is determined by a probability distribution. These two parameters are estimated from field data set in a robust way so that the simulated patterns reflect the observed heterogeneity. We apply this model to entomological data: four Diptera families, namely the Sciaridae, Phoridae, Cecidomyiidae, and Empididae. The field data for the Phoridae family are used to simulate sampling using different trap sizes. We record changes in the coefficient of variation (C) as a function of the sampling scale, and we can suggest to ecologists emergence traps of 0.6 m², in other words a square 77 × 77 cm trap, to obtain a C value under 20%. Received: February 28, 2000 / Accepted: October 14, 2000     

The spatial distribution,contamination, and ecological risk assessment of heavy metals of farmland soils in Karashahar–Baghrash oasis,northwest China

The issue of heavy metal pollution is of high concern due to its potential health risks and detrimental effects on human beings, animals, and plants. In this study, farmland soil samples from 79 sampling sites were collected in Karashahar–Baghrash oasis, northwest China, and the contents of eight heavy metal elements (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn) were determined by standard methods. The spatial distribution, pollution, and ecological risks of heavy metals were analyzed based on Geographical Information System (GIS) technology, contamination factor (CF), pollution load index (PLI), and potential ecological risk index (RI). Results indicated that: (1) The average contents of Cd, Cr, Ni, Pb, and Zn exceeded the background values of irrigation soils of Xinjiang by 54.0, 1.34, 1.39, 3.44, and 5.01 times, respectively. The average contents of Cd exceeded the national standard of China by 10.80 times; (2) The pollution order of CF was ranked as Cd > Zn > Pb > Ni > Cr > Cu > As > Mn, and the ecological risk order of E_rⁱ was ranked as Cd > Ni > As > Cu > Ni > Pb > Cr > Zn. The average PLI of the study area showed heavy pollution level, and the average RI of the study area fell into considerable risk; (3) The moderately polluted areas with moderate potential ecological risks distributed in the northern parts, whereas heavily polluted areas with considerable potential ecological risks distributed in the southern parts of the study area; (4) Cr, Cu, and Mn of farmland soils were mainly originated from natural factors. Cd, Ni, and Pb were mainly originated from anthropogenic factors. As and Zn may be associated with both natural and anthropogenic factors. Cd contributed most to the PLI and RI of the farmland soils in the study area.     

Risk assessment of GM plants: avoiding gridlock?

Cultivation of genetically modified crops is presently based largely on four crops containing few transgenes and grown in four countries. This will soon change and pose new challenges for risk assessment. A more structured approach that is as generic as possible is advocated to study consequences of gene flow. Hazards should be precisely defined and prioritized, with emphasis on quantifying elements of exposure. This requires coordinated effort between large, multidisciplinary research teams.     

Finite element–based injury metrics for pulmonary contusion via concurrent model optimization

This study explores the relationship between impact severity and resulting pulmonary contusion (PC) for four impact conditions using a rat model of the injury. The force–deflection response from a Finite Element (FE) model of the lung was simultaneously matched to experimental data from distinct impacts via a genetic algorithm optimization. Sprague-Dawley rats underwent right-side thoracotomy prior to impact. Insults were applied directly to the lung via an instrumented piston. Five cohorts were tested: a sham group and four groups experiencing lung insults of varying degrees of severity. The values for impact velocity (V) and penetration depth (D) of the cohorts were Group 1, (V = 6.0 m · s⁻¹, D = 5.0 mm), Group 2, (V = 1.5 m · s⁻¹,D = 5.0 mm), Group 3, (V = 6 m · s⁻¹, D = 2.0 mm), and Group 4, (V = 1.5 m · s⁻¹, D = 2.0 mm). CT scans were acquired at 24 h, 48 h, and 1 week post-insult. Contusion volume was determined through segmentation. FE-based injury metrics for PC were determined at 24 h and 1 week post-impact, based on the observed volume of contusion and first principal strain. At 24 h post-impact, the volume of high radiopacity lung (HRL) was greatest for the severe impact group (mean HRL = 9.21 ± 4.89) and was significantly greater than all other cohorts but Group 3. The concurrent optimization matched simulated and observed impact energy within one standard deviation for Group 1 (energy = 3.88 ± 0.883 mJ, observed vs. 4.47 mJ, simulated) and Group 2 (energy = 1.46 ± 0.403 mJ, observed vs. 1.50 mJ, simulated) impacts. Statistically significant relationships between HRL and impact energy are presented. The FEA-based injury metrics at 24 h post-contusion are e_max·[(e)\dot]_max{\varepsilon_{\max}\cdot \dot {\varepsilon}_{\max}} exceeding 94.5 s⁻¹, ε _max exceeding 0.284 and [(e)\dot]_max{\dot{\varepsilon}_{\max}} exceeding 470 s⁻¹. Thresholds for injury to the lung still present at 1 week post-impact were also determined. They are e_max·[(e)\dot]_max{\varepsilon_{\max}\cdot \dot {\varepsilon}_{\max}} exceeding 149 s⁻¹, ε _max exceeding 0.343 and [(e)\dot]_max{\dot{\varepsilon}_{\max}} exceeding 573 s⁻¹. A mesh sensitivity study found that thresholds based on strain rate were more sensitive to changes to mesh density than the threshold based on strain only.     

Pollution,source, and ecological risk assessment of trace elements in surface sediments of Lake Aktaş, NE Turkey

This study applies ecological indices to determine the anthropogenic-based metal enrichment and potential ecological and ecotoxicological risks posed by each metal in the sediments of Lake Akta?, NE Turkey. Sediment samples were collected from nine stations (St1–St9) within the Turkish boundary of Lake Akta? and the heavy metal, total organic carbon %, CaCO₃%, chlorophyll degradation products (chlorophyll-α), total sulfur %, and total phosphate % contents in the sediment samples were determined. Enrichment factor (EF), pollution load and potential ecological risk (PER) indices were calculated to shed light on the ecological effects of heavy metals. The metal content was ranked in descending order of Al > Fe > Mn > Zn > Ni > Cr > Cu > Pb > As > Cd > Hg. The EF values ranged 0.87–1.0 for Cu, 1.04–1.14 for Pb, 1–1.08 for Zn, 0.88–0.95 for Ni, 0.99–1.24 for Mn, 0.89–0.93 for Fe, 0.82–1.01 for As, 0.96–1.19 for Cd, 0.94–1.0 for Cr, and 1.42–1.90 for Hg. Minimal contamination was found for Hg. Pollution load, PER, and toxic risk indices indicated no ecological risk currently. However, considering the PER index for metals individually, a moderate potential risk was detected for Hg. The data obtained from multivariate statistical analyses indicate that Hg and Mn originate from the atmosphere, while other elements have lithogenic sources.     

Constructing a personalized prognostic risk model for colorectal cancer using machine learning and multi-omics approach based on epithelial–mesenchymal transition-related genes

The progression and the metastatic potential of colorectal cancer (CRC) are intricately linked to the epithelial–mesenchymal transition (EMT) process. The present study harnesses the power of machine learning combined with multi-omics data to develop a risk stratification model anchored on EMT-associated genes. The aim is to facilitate personalized prognostic assessments in CRC. We utilized publicly accessible gene expression datasets to pinpoint EMT-associated genes, employing a CoxBoost algorithm to sift through these genes for prognostic significance. The resultant model, predicated on gene expression levels, underwent rigorous independent validation across various datasets. Our model demonstrated a robust capacity to segregate CRC patients into distinct high- and low-risk categories, each correlating with markedly different survival probabilities. Notably, the risk score emerged as an independent prognostic indicator for CRC. High-risk patients were characterized by an immunosuppressive tumor milieu and a heightened responsiveness to certain chemotherapeutic agents, underlining the model's potential in steering tailored oncological therapies. Moreover, our research unearthed a putative repressive interaction between the long non-coding RNA PVT1 and the EMT-associated genes TIMP1 and MMP1, offering new insights into the molecular intricacies of CRC. In essence, our research introduces a sophisticated risk model, leveraging machine learning and multi-omics insights, which accurately prognosticates outcomes for CRC patients, paving the way for more individualized and effective oncological treatment paradigms.     

Prevalence of dermal pathway dominance in risk assessment of contaminated soils: A survey of superfund risk assessments, 1989–1992

Exposure to soil‐borne contaminants can occur through ingestion, inhalation and/or dermal absorption. A study was undertaken to assess the relative frequency with which dermal exposures are predicted to pose the greatest risk attributable to contaminated soils in Superfund risk assessments. Screening of over 200 risk assessments from the period 1989–1992 resulted in identification of 37 sites at which projected lifetime excess cancer risks attributed to dermal contact with soil were greater than the nominal regulatory threshold of 1.10^‐4. At 19 of these sites, the dermal/soil pathway is estimated to contribute the largest carcinogenic risk associated with surface soil contamination, and may therefore drive cleanup of that medium. At 9 of the sites, the dermal/soil pathway is predicted to present a higher carcinogenic risk than any other pathway. Chemical contaminant type and estimates of soil adherence and surface area exposed appear to be the primary factors that distinguish sites at which dermal/soil pathway carcinogenic risk estimates are elevated relative to other exposure pathways. Quantification of exposure parameters, especially those related to behavior, remains a significant need.     

Characteristics of a nickel–albumin binding assay for assessment of myocardial ischaemia

Background: The aim of this study was to describe a method to measure ischaemia-induced alterations of the binding capacity of serum albumin to exogenous nickel.

Methods: We measured the levels of cardiac troponin I (cTnI), serum albumin, ischaemia-modified albumin (IMA) measured by a cobalt–albumin binding assay (CABA), and a nickel–albumin binding assay (NABA) in the following groups: myocardial infarction (n?=?32) and non-ischaemic chest pain (n?=?64).

Results: IMA, cTnI and NABA levels were higher in the myocardial infarction group. NABA presented a higher ability to discriminate myocardial ischaemia than CABA.

Conclusions: Patients with myocardial infarction have reduced nickel binding to human serum albumin, and NABA may have an important role as an early marker of myocardial ischaemia.     

An evaluation of ecological information on Australia’s northern tropical rivers and wetlands

The northern tropical river and wetland systems of Australia cover a vast and mostly remote area. Comparably little is known of wetland type, species diversity, ecological processes and ecosystem services. Systematic inventory and classification is lacking and research remains disparate in purpose and coverage. An integrated framework is used to evaluate results from three multidisciplinary studies across various scales to synthesise available knowledge relating to key ecological attributes across both the study region and within focus areas. The utility of geomorphic and hydrological classification at coarse scales is supported but the unavailability of biological data at corresponding and finer spatial and temporal scales constrains the potential for ecological inventory and classification utilising existing information. Future inventory and ecological studies across this and similar vast study areas need to consider the apriori development of a user-driven data framework and the development of specific investigatory tools to overcome technical and other barriers associated with the requirements of multi-scalar ecological studies.     

A climate goal–based,multicriteria method for system evaluation in life cycle assessment

The International Journal of Life Cycle Assessment - Our ability to restrict global warming to the established objectives in the Paris Agreement depends on the metrics used to evaluate the climate...