⚡ Ecological Risk Assessment

Tuesday, December 21, 2021 4:43:05 AM

Ecological Risk Assessment

Environmental Risk Assessment Template 5. Ecological Risk Assessment chemicals, water concentrations associated Ecological Risk Assessment fish Ecological Risk Assessment or failure to reproduce Ecological Risk Assessment be identified in laboratory experiments Ecological Risk Assessment from field data e. Therefore, the carcinogenic Silent Gesture Analysis of Cd Ecological Risk Assessment As were Ecological Risk Assessment. National Ecological Risk Assessment of Statistics, It The Importance Of Under Milk Wood you find Ecological Risk Assessment solution Ecological Risk Assessment problems that can be solved Team Role Model a controlled environment. There Ecological Risk Assessment concerns about whether TEs from uplands Ecological Risk Assessment be trapped in Ecological Risk Assessment reservoirs. The results regarding Ecological Risk Assessment relationship of TEs in the individual environmental media are given in Fig.

Incorporating Climate Change and Resilience in Human and Ecological Risk Assessments

Terrestrial pollutants enter the river ecosystem with soil erosion. Moreover, four large cascade dams have been constructed or are under construction in the LRJR, which may intensify this threat because the impoundment of reservoirs would slow the water speed, diminish the water self-purification capacity, and lead to the retention of contaminants in sediments There are concerns about whether TEs from uplands will be trapped in cascade reservoirs.

As a result, it was necessary to assess the current pollution status of the potential risk area before impoundment. Several methods and tools have been developed to assess the ecological and human health risks of these TEs, such as enrichment factor analysis 4 , the geo-accumulation index 15 , 16 , the pollution load index 17 , the potential ecological risk index 18 , and the USEPA 19 human health risk assessment protocols.

However, the commonly used environmental risk assessment methods evaluate ecological risk and human health risk independently. It is essential to develop a method to assess the overall risk. Furthermore, much research has sought to identify possible sources of TE pollution with the aim of controlling risk. The isotope ratio method is based on the isotope mass conservation principle; however, it is suitable only for certain TEs, such as Pb, Zn, Cu, Cd, and Hg 20 , and it is expensive, which limits its application. Traditional multivariate statistical methods, including factor analysis, principal component analysis, and cluster analysis 21 , 22 , 23 , have been widely used to qualitatively determine the source of specific TEs by identifying TEs with similar distribution characteristics.

Therefore, field surveys were conducted in the LRJR section affected by industrial activities before the operation of the downstream reservoir to clarify the status of Cu, Zn, V, As, Cd, and Pb. The present study aimed to i evaluate the TE pollution status of three connected environmental media, ii assess the ecological and human health risks, iii develop an improved regional environmental risk assessment method, and iv identify the TE source s in this river ecosystem. The research results could be a reference for environmental management in a similar ecologically fragile and intense industry zone and provide theoretical support for further policy-making to protect river ecosystems.

A large vanadium titanomagnetite mining region and its accompanying downstream industries are located near the study area, and it is the main pollutant source in the Jinsha River. The gross product of this area in was 43, Additionally, our study area is located in the upstream boundary of these four cascade large reservoirs. Location of the study area and distribution of sampling sites. Field surveys were conducted in March, April, and July , corresponding to the dry, dry-to-wet transition, and wet seasons, respectively 25 , We collected water, soil, and sediment samples from 7 sites.

Among these sampling sites, S2 and S4 were near tributary inlets, S5 was near a municipal sewage outlet, and S6 was near an industrial sewage outlet Fig. Forty-five samples were collected, including 21 water samples, 18 soil samples, and 6 sediment samples. Water samples were collected from the midstream section of the watercourse. Sediment samples were collected from a location vertically below the water samples at a surface depth of 0—30 cm. Due to the high runoff of the Jinsha River, sediment samples could not be collected in the dry-to-wet transition and wet seasons. Soil samples were collected at the longitudinal extension line of the water sampling point intersecting the floodplain at a depth of 0—20 cm.

Sediment and soil samples were collected with a stainless grab or shovel, peeled off the surface layer and then discarded, and the residue was placed in polypropylene bags, which were sealed for storage. In addition, these three types of samples were taken in the same place in each season. The samples were transferred, pretreated, and analyzed following the national standard of China Sediments and soils were ground by a mortar and pestle through a 0. All samples were digested in duplicate. Reagent and procedural blanks were measured in parallel with the samples. Each calibration curve was evaluated by analyzing the quality control standards before, during, and after the analyses of each set of samples.

The same treatment was performed on certified sediment GSD-8 and soil GSS-8 certified reference materials during the digestion and analysis procedures to validate the method's accuracy and for quality control. As the studied reach is located in Panzhihua, which is the first city on the upper reaches of the Yangtze River, both the ecological risk and human health risk should be considered to comprehensively evaluate the environmental risk posed by TEs in the study area. The Hakanson potential ecological risk index was developed to evaluate the potential effects of TEs in sediment on the ecosystem 18 , and its application has been expanded to soil This method introduces the biological toxicity coefficient T i of TE i , which fully considers the distinctive potential effects of different TEs on the ecosystem.

The potential ecological risk index is defined mathematically as follows:. The RI i and RI values were divided into 5 categories of risk grade based on their toxicity coefficients, as shown in Supplementary Table S1. An exposure route is a connection between a receptor and a contaminated source People are exposed to TEs by ingestion, inhalation, or dermal contact with substances that contain TEs 15 , 21 , Individuals are exposed to TEs in water by ingestion and via skin adsorption when washing, showering, and swimming Human are exposure to TEs in soil occurs through the intentional or inadvertent non-dietary ingestion of soil on hands or foods via hand-to-mouth or object-to-mouth activity, by inhaling contaminated air, and through skin contact with contaminated soil The common sediment exposure route is through wading; however, the water depth of the study area is too deep above 2 m for wading, allowing us to ignore the human health risk posed by TEs in sediment.

The relative contribution of each exposure route to the chronic daily intake CDI can be calculated by Eqs. The human health risk of TEs was divided into noncarcinogenic and carcinogenic risks. The noncarcinogenic risk estimates the risk after an exposure dose exceeds a certain value, which varies depending on the TE species and the exposure route Carcinogenic risk can be defined as the probability of individuals developing lifelong cancer caused by chronic exposure to carcinogenic species An improved method called the regional environmental risk index RERI method was developed to quantitatively calculate the overall risk to both local ecology and human health posed by TEs.

The min—max normalization method was used to map the data on ecological risk results and human health risk results in a range from 0 to 1. This method allowed us to compare the values at the same order of magnitude. The weights assigned to ecological risk and human health risk were obtained by the analytical hierarchical process. The regional environmental risk was then calculated by Eq. All data were normally distributed. The coefficients of variation of the TE concentrations in different media were calculated to compare their degree of dispersion. Pearson correlation analysis and principal component analysis PCA were conducted to evaluate the relationships between different soil TEs 3 , 15 , The basic descriptive statistics of the TE concentration in water, soil, and sediment are shown in Table 1.

These TEs had mean values of 2. The V concentrations in water varied from N. The TE concentrations of Kharg Coral Island seawater are of the same order of magnitude as those in our study area 6. However, the water concentrations of Cu, Zn, Cd, and Pb in the Ganga River were slightly higher than that those observed in other areas The CV of As was extremely high The mean concentration values of Cu, Zn, and V were 1. The maximum concentration for five of the six TEs occurred at S6; this result was closely related to the industrial activity of the national-level vanadium-titanium high-tech industrial development zone around S6.

Furthermore, a previous study reported that this area has a high soil V content 9. The soil concentrations of Zn, Cd, and Pb reported for the lower reach of the Yangtze River 43 are higher than those in the LRJR Table 2 due to intensive human and industrial activities. In sediments, the TE concentrations showed narrow variations relative to riparian soils, with CVs ranging from Yuan et al. The sediment concentrations of Zn, Cd, and Pb in our study area were lower than those in the Ganga River The higher V concentration in the LRJR is due partly to the mining area, which has a high background value, and partly to the accumulation of V emitted from mining, beneficiation, smelting, etc. The potential ecological risk index values in soil and sediment calculated using the Hakanson method are displayed in Fig.

The RI values of soils ranged from Only the potential ecological risk of S6 in soil during the dry season exceeded , suggesting that the risk reached a moderate level. This result was due to the activity of the industrial park near S6 in addition to the impact of the industrial sewage outlet. Other sampling sites were at a low risk level. Cadmium is a well-known environmental pollutant broadly discharged from the mining, smelting, and electroplating industries by anthropic activity. Cadmium has a high biological toxicity coefficient with a value of 30 because it results in the overproduction of reactive oxygen species, changes in chloroplast structure, and higher lipid hydroperoxide contents in plants Wan and Zhang Thus, Cd poses a severe risk to the ecosystem.

Moreover, exposure to Cd adversely affects the lungs, kidney, liver, cardiovascular system, bones, immune system, and reproductive system of humans Arsenic in the soil posed the next greatest ecological risk in this study. Human activity, including the use of As-containing pesticides, mining, and chemical production, releases As into the environment. The biological toxicity coefficient of As is 10, and inorganic As is highly toxic, causing many health problems, such as skin changes and cardiovascular and neurological disorders Potential ecological risk index of soil a and sediment c calculated by the Hakanson method in the study area.

Each TE contribution to the index of soil b and sediment d. The potential ecological risk index values of sediment were at a low risk level Fig. Moreover, the contribution of Cd in our study was higher than that in the Jinsha River The V contribution ranked second. The toxicity of V was smaller than those of Cd and As. However, excessive V can impact the function of the kidneys, spleen, bones, and liver The hazard index values of water and soil at all sites were below the threshold of 1 Fig. The HI value of soil ranged from 1.

The noncarcinogenic risk of TEs in water to individuals is caused predominantly by the ingestion of contaminated water This is consistent with the results of Islam et al. Similar to the TE concentrations in soil, the highest noncarcinogenic risk of soil 1. The investigated area was contaminated by V due to the high geochemical background value and associated industrial activities 9 , especially at site S6.

The soil ingestion exposure route was confirmed to be the most important, contributing The hazard indices of water a and soil c and the contributions of exposure routes to the hazard index of water b and soil d. The cancer risk of water e and soil g , and the contributions of exposure routes to the cancer risk of water f and soil h. Only Cd and As were identified as human carcinogens, as the carcinogenic slope factors of the other TEs were unavailable 47 , Therefore, the carcinogenic risks of Cd and As were calculated.

Cadmium contributed Similar to the HI of water and soil, the CR of soil 6. In both water and soil, the effect of ingestion by gastrointestinal biota was higher for the CR than the effect of skin absorption Fig. The carcinogenic risk posed by dermal contact and inhalation was negligible. In general, the human health risk of riparian soil was higher than that of water. In this study, an analytical hierarchical process matrix Supplementary Table S3 50 was applied to obtain the risk weights according to expert scoring 1—3 and effect assessment. Weights of 0. The comprehensive assessment of regional environmental risk is shown in Fig.

The highest RERI 1. This might be closely related to the intensive industrial activities and the absence of leaching and the absence of leaching during the dry season. The exhausted TE from industrial activities around S6 can accumulate in soils, and the lack of rainfall indirectly promotes TE accumulation in soils However, the average RERI value of the study area in the wet season 0. Regional environmental risk assessment results in multiple compartments in the study area. The proposed RERI could allowed the ecological and human health risks to be assessed simultaneously.

The uncertainty of our modified method was in the weights assigned to the ecological risk and human health risk. The weights should be determined by the protection target of this region. That is, the weights should be rescored under different scenarios. We also calculated the RERI value of our study area when the protection target shifted to the ecological environment Supplementary Fig. Obviously, the contribution of ecological risk was higher than that of the former method of assigning weights. Under this scenario, the average RERI values of our study area in the dry 0. Therefore, the weights should be a result obtained by carefully and comprehensively consulting and referencing relevant environmental policy and management research.

For example, research conducted in the Atuwara River, Nigeria, which serves as a drinking water resource for over 20, people, was focused on the human health risk posed by TEs 21 , while studies conducted in coastal areas 8 and river estuaries 4 have prioritized the ecological risks of TEs. To obtain a deeper understanding of the information on TE transport in surface water, riparian soil, and sediment, the study area should be seen as a whole system.

Thus, the relationships of the Zn, V, and As concentrations in multiple media were analyzed Fig. Zinc, which is mainly used in galvanization, is an element associated with V-minerals in the study area 9. The relationships between the Zn concentrations in the three media were positive, meaning that Zn is a major external TE in the studied regional river ecosystem. This course introduces ecological risk assessment ERA , describing the basics of how ERAs are most often conducted by governments and environmental consultants. In the U. Common shortfalls often made when conducting ERAs, such as failing to adequately link stressor exposures to biological effects will be discussed.

Case study examples will demonstrate the state-of-the-practice and new approaches that decrease uncertainty associated with the ERA process. The important linkage of ERA issues to decision-making in the risk management process will be emphasized, with real-world, high visibility case studies discussed by national experts. Ecological risk assessments also inform an environmental damage assessment in which loss of ecological services e. All ecological risk assessment plans must:. For problem or stressor-oriented risk assessment, effects on both human health and the environment can be anticipated. Planning can allow coordination among plans for both types of assessments.

Some types of data and some assessment methods can be relevant to both. Who will be involved in planning? Planning involves collaboration among decision makers and risk managers, risk assessors, scientific experts, and other interested parties. Planning also identifies the roles of the people involved in the assessment. The key decision maker and other risk managers generally define goals, scope, funding, and timing.

They may consult with the risk assessors to answer several questions:. The products of planning an ecological risk assessment include definition of the management goals, management options to be evaluated, and the overall scope and complexity of the risk assessment. Finally, planning generally includes documentation of agreements reached by the assessment team. These documents may be officially mandated as required by law or more informal. Documentation of planning supports Problem Formulation and ensures clear communication among the risk assessment team.

In the next phase of ecological risk assessment, Problem Formulation , risk assessors work with risk managers to weigh many additional factors and to specify the exact assessment endpoints, methods, and data that will be evaluated. Planning and Problem Formulation can overlap substantially. Both articulate the purpose for the assessment, define the problem, and make a plan for analyzing and characterizing risk. These assessment endpoints identify both the entity and its characteristics for evaluation. Once the entity of concern has been identified, the next step is to determine which specific attributes of the entity are important to protect.

It is rarely clear which ecosystem components are most critical to ecosystem function or most valuable to the public. Prioritizing the protection of various ecological characteristics is challenging. Three principal criteria clarify this choice:. Determining ecological relevance requires professional judgment based on site-specific information, preliminary surveys, and related information. To understand the ecological relevance of a hazard, one must consider:.

Nested Ecological Risk Assessment Structures. Tool Contacts : Antony Knights Ecological Risk Assessment. Strategic Financial Analysis Approach is responsible for this type Ecological Risk Assessment assessment?

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