Levels Of Human Activity Research Articles

Potential Sources, Pollution, and Ecological Risk Assessment of Potentially Toxic Elements in Surface Soils on the North-Eastern Margin of the Tibetan Plateau.

Due to increased levels of human activity, various pollutants are frequently detected on the Tibetan Plateau, where the environment is extremely fragile and sensitive. Therefore, this study investigated the sources, pollution, and ecological risks of soil potentially toxic elements (PTEs) in different landscape areas within the Qaidam Basin in the northeastern part of the Qinghai–Tibet Plateau. The contents of seven PTEs (Cd, Cu, Pb, Zn, As, Cr, and Ni) in 32 topsoil samples (0–2 cm) were analyzed in different regions of the Qaidam Basin. The concentrations of As, Cd, Cr, Cu, Ni, Pb, and Zn were 10.4–29.9 mg/kg, 0.08–4.45 mg/kg, 19–66 mg/kg, 8.2–40 mg/kg, 11.7–30.8 mg/kg, 11.1–31.2 mg/kg, and 32–213 mg/kg, respectively. The correlation between Pb and Cd in unpopulated areas was 0.896 (p < 0.01). The correlations among Pb, Cd, and Zn in agricultural areas, among As, Cd, Cr, and Zn in saline lake areas, and among As, Cd, Cr, Cu, Ni, Pb, and Zn in residential areas were all greater than 0.65 (p < 0.05). The principal component analysis results showed that Pb and Cd in unpopulated areas, Pb, Cd, and Zn in agricultural areas, As, Cd, Cr, Zn, and Pb in saline lake areas, and As, Cd, Cr, Cu, Ni, Pb, and Zn in residential areas were affected by human activities (significant factor >0.70). Based on the geological accumulation index and single-factor pollution index results, the maximum Cd values were found to be 4.93 and 45.88, respectively; Cd was thus the most serious PTE pollutant. The comprehensive pollution index of Nemero showed that moderately and severely polluted areas accounted for 18.89% and 18.46% of the total area, respectively. The results of the potential risk index showed that very strong and strong ecological risk points together accounted for 18.8% of the total points. The spatial variations in PTE pollution and the potential ecological risk index had similar patterns; both increased from the unpopulated areas in the northeastern Qaidam Basin to Golmud city in the south-western Qaidam Basin. These results indicate that human activities negatively impacted the soil ecological environment in the Qaidam Basin during the rapid development of the economy and urbanization and that these negative impacts tended to spread to unpopulated areas. Therefore, it is necessary to emphasize the significant impacts of human activities on environmental quality and formulate preventive measures to reduce PTE pollution in the Qinghai–Tibet Plateau.

Review of the Book “Particularităţile creării şi aplicării de către state a normelor de drept internaţional” [The particularities of the creation and application by states of the norms of international law], Author - Dumitriţa Florea, Lumen Publishing House

The work entitled "Peculiarities of the creation and application by states of the norms of public international law" emphasizes the analysis of the role of the state in the formation of international legal norms. This scientific approach is an integral part of the doctrine of public international law and details issues related to the ways of creating and applying the norms of public international law and the participation of sovereign states in the process of creating international legal norms.&#x0D; Currently, we are witnessing a transformation of international rules, a fact that generates close observation and analysis of the dynamics of international relations. It is almost impossible to have a good understanding of the current status of international law and its role, without placing its evolution within the international society that actually constitutes its natural environment. International society encompasses a plurality of component elements that seek unity, beyond their diversity, both at the level of states and at all levels of human activity.

Impacts of sea ice on marine dynamics in western Laizhou Bay, Bohai Sea

The Bohai Sea is a region with wintertime sea ice development and high levels of human economic activity, where sea ice has a powerful destructive effect on maritime transportation and ocean engineering. In the Bohai Sea, sediment resuspension caused by waves and currents has not previously been systematically studied during periods of ice cover. In the winter of 2009–2010, severe ice conditions with a recurrence period of 30 years occurred. In this study, wave, residual water level (RWL), residual current (RC), and suspended sediment concentration (SSC) data were collected by two seabed-based observation stations (QD12 and QDG2) for one continuous year during both ice-covered and ice-free conditions. The data were systematically compared and analyzed. Generally, the results showed that sea ice coverage had a clear suppressing effect on the significant wave height (Hs) and RWL. Hs decreased by almost 50%, and RWL decreased by 0.19 m and 0.10 m during ice-covered conditions at two stations. Sea ice coverage had a suppressing effect on the sediment resuspension due to a reduction in wave induced shear stress. The reduction of sea level and SSC was mainly reflected in the decrease of fluctuation amplitude and overall magnitude, and the suppression effect was more obvious in conditions of strong wind. The RC velocity varied during periods of ice cover in Laizhou Bay. Sea ice enhanced RC velocity during the destruction period. The RC velocity increased dramatically at station QD12 probably due to the long length of the destruction period, but decreased slightly at station QDG2 possibly due to a shorter destruction period and the blocking of Weifang Port. The enhanced RC in the destruction period carrying broken ice caused significant damage to coastal engineering projects. The suppressing effects of sea ice on Hs, RWL, and sediment resuspension, and the strengthening effects on RC velocity were both closely related to the wind speed and direction. This study reveals the effects of sea ice on local hydrodynamics and sediments, providing important reference values for the generation and disappearance of sea ice in mid- and high-latitude bays under the background of dramatic global climate change.

Determinants of Artistic Information Identification of the Olympics Ceremonial Suit

The purpose of the article. To analyze the Olympics ceremonial suit of the XXXII Olympic Games «Tokyo 2020» and to form promising defining features of its artistic and informational identification. The research methodology provides art analysis of the formation, artistic motives, national appeals, general aesthetics and modern trends that are accumulated in the design of the Olympic ceremonial suit of foreign sports teams. The scientific novelty is to study the Olympics ceremonial suit of Tokyo 2020 Olympics and identify promising strategic advertising features of its artistic and informational identification. Conclusions. As a result of the research for further application in the design of the Olympic ceremonial suit promising strategic advertising features of artistic and informational identification are identified, including: 1) Convergence of appeals to the colors of the national flag in the design of the analyzed ceremonial Olympics suits of sports teams; 2) Correspondence of artistic and informational identification of ceremonial suits to the basic principles of the Olympic Games; 3) Eco-friendliness in an Olympics formal suit, which involves not only the use of environmental materials in the design of clothing, but is also aimed to draw attention to the global problem of mankind. Excess raw materials with a long service life and proper technological utilization of light industry waste has become a trigger for increased attention to environmental awareness at all levels of human activity. High fashion dictates the trends for -middle and mass market and is gradually moving to safe textile materials that are biodegradable without contaminating the water with micro-plastic; 4) Vestimentary traditions in the artistic and informational identification of the Olympics ceremonial suit, which allow to see the designer (design studio, company, etc.) as a referent of the sign system of artistic and informational identification of the Olympics ceremonial suit together with athletes and representatives of the delegation, which is also the brand of the country for which the suit is created.

Is the effect of human activity on air pollution linear or nonlinear? Evidence from Wuhan, China, under the COVID-19 lockdown

This study explores the fundamental question of how and how much human activity affects air quality. It focuses in particular on whether this relationship is linear or nonlinear and provides suggestive results to the intriguing mechanism. To determine that answer, we make two important assumptions about the impact of human activity on air quality that we then test using a new analytical framework. In early 2020, the period of lockdown in Wuhan, China, due to the COVID-19 pandemic offers “extreme” observations with which we can test our assumptions from the perspective of either differences or ratios. In addition to offering a theory with a novel design, we also introduce statistical methods that are suitable for empirically estimating and testing our assumptions and obtaining suggestive results. Moreover, we construct a precise equation in quadratic form for examining the marginal effects of several types of air quality indicators/metrics concerning human activity as well as some important control variables for both natural and social factors. The level of human activity, measured as the index of travel intensity, that has the largest effect on air quality is around 1.657 for the most common urban air pollutants. This study implies that urban air quality can be improved more effectively by avoiding regions where human activity has the maximum marginal effect on increases in urban air pollution. This implication for urban policy and planning is valuable both domestically and globally.

Pelagic ecosystem dynamics between late autumn and the post spring bloom in a sub-Arctic fjord

Marine ecosystems, and particularly fjords, are experiencing an increasing level of human activity on a year-round basis, including the poorly studied winter period. To improve the knowledge base for environmentally sustainable management in all seasons, this study provides hydrographic and biological baseline data for the sub-Arctic fjord Kaldfjorden, Northern Norway (69.7° N, 18.7° E), between autumn 2017 and spring 2018. Field observations are integrated with results of a numerical ocean model simulation, illustrating how pelagic biomass, represented by chlorophyll a (Chl a), particulate organic carbon (POC), and zooplankton, is affected by stratification and circulation from October to May. We observed an unusually warm autumn that likely delayed the onset of cooling and may have supported the high abundances of holoplankton and meroplankton (5768 individuals m–3). With the onset of winter, the water column cooled and became vertically mixed, while suspended Chl a concentrations declined rapidly (&amp;lt; 0.12 mg Chl a m–3). In January and February, suspended POC concentrations and downward flux were elevated near the seafloor. The hydrodynamic model results indicate that the strongest currents at depth occurred in these months, potentially inducing resuspension events close to the seafloor. In spring (April), peak abundances of suspended biomass were observed (6.9–7.2 mg Chl a m–3 at 5–15 m; 9952 zooplankton ind. m–3 at 0–100 m), and field observations and model results suggest that zooplankton of Atlantic origin were probably advected into Kaldfjorden. During all investigated seasons, the model simulation suggests a complex circulation pattern, even in such a small fjord, which can have implications for environmental management of the fjord. We conclude that the pelagic system in Kaldfjorden changes continually from autumn to spring and that winter must be seen as a dynamic period, not a season where the fjord ecosystem is ‘at rest’.

Impact of the Corona Virus Pandemic on Wetland Avifauna Diversity of JAT Region

Coranavirus pandemic affected not only humans, but also it was affected to the avian biodiversity of Jath region. One of the reasons of decreasing avifauna of wetland birds is human anthropogenic activities. During Pandemic the lockdown was done by government that showed positive effect on the biodiversity. The Tippehalli reservior is nearer to the sugar factory, the loud voice of siren, the human activities decreased the avifauna. Due to lockdown the sugar factory was closed, that duration some species of birds quickly respond to the lower levels of human activities. Lockdown plays positive effect to the avi fauna biodiversity.

Elevated Serum Purine Levels in Schizophrenia: A Reverse Translational Study to Identify Novel Inflammatory Biomarkers.

BackgroundImmunological markers and related signaling molecules in the blood are altered in schizophrenia mouse models, in acutely relapsed patients with schizophrenia, and in persons at a clinically high risk for subsequently developing psychosis, highlighting their potential as prognostic and theranostic biomarkers. Therefore, we herein aimed to identify novel potential biomarkers in the serum that are associated with purinergic signaling.MethodsTo our knowledge, this is the first study to assess the correlations among the levels of human serum adenine nucleotides (ATP, ADP), adenosine, P2X7 receptor, and disease activity in patients hospitalized due to an acute relapse of schizophrenia (n = 53) and healthy controls (n = 47). In addition, to validate these findings using a reverse translational approach, we examined the same parameters in an acute phencyclidine-induced schizophrenia mouse model.ResultsWe found consistently elevated levels of ATP, ADP, interleukin (IL)-6, and IL-10 in both schizophrenia groups compared with the controls. The levels of adenosine, IL-1β, IL-12, and C-reactive protein were also increased in the human patient samples. Moreover, ATP and ADP were significantly positively correlated with the Positive and Negative Symptom Scale item “lack of judgment and insight”; IL-1β, IL-12, and tumour necrosis factor alpha were significantly positively correlated with “tension” and “depression”; and “disorientation” and “poor attention” were correlated significantly with IL-6 and IL-8.ConclusionsOur study suggests the promising potential of blood purines and inflammatory markers as future prognostic tools.

Definition and calculation of hierarchical ecological water requirement in areas with substantial human activity—A case study of the Beijing–Tianjin-Hebei region

In areas with high levels of human activity, there is often an imbalance between the supply and demand of water resources. This often means that ecological water requirements (EWRs) cannot be met in the long term, which leads to a deterioration in the ecological environment. To protect the ecological environment in areas with considerable human activity, research into hierarchical EWRs is essential. This paper first defined the hierarchical EWR concept (the minimum, suitable and ideal EWR) in areas with substantial human activity, and then developed a method to calculate this requirement over a large-scale area, taking the Beijing–Tianjin–Hebei region in China as a case study. Results showed that the minimum EWR in the Beijing–Tianjin–Hebei region was 42.81 × 108 m3, the suitable EWR was 54.37 × 108 m3, and the ideal EWR was 70.01 × 108 m3. The EWR of 13 cities in the region was calculated. The water requirement in the central area of Beijing–Tianjin–Hebei was significantly higher than that of the southern or northern areas. The EWR rate was used to characterize the EWR as a proportion of the surface water resources. The results showed that the minimum, suitable and ideal EWRs for Beijing–Tianjin–Hebei were 39%, 49%, and 63%, respectively. It was calculated that the annual average ecological water supply guarantee rate of Beijing–Tianjin–Hebei from 2015 to 2019 was 46%, which generally met the minimum EWR. This paper provides technical methods and a reference for calculating the EWR over large-scale areas with considerable human activity.

Outdoor Wind Comfort and Adaptation in a Cold Region

The outdoor wind comfort is important for evaluations of the urban wind environment. The existing wind comfort criteria are based on the correlations between wind parameters, human activity levels, and wind comfort level categories. These criteria vary among different climates and regions, and they are influenced by meteorological parameters and human wind adaptation. In this study, an outdoor wind comfort questionnaire survey was conducted and meteorological measurements were collected in Xi’an, which is located in the cold region of China. The square and lake side were chosen as the test sites. The mean wind sensation vote (MWSV) and wind speed of neutral wind sensation were used as indexes to analyze the correlation between outdoor wind comfort and human wind adaptation. The results showed that the wind sensation level was generally moderate. At −1 &lt; MWSV &lt; 1, the fluctuations in the wind speed had little effect on the wind sensation, but when MWSV &gt; 1 or MWSV &lt; −1, the degree of discomfort increased as the absolute value of MWSV increased. When the wind speed exceeded 1 m/s, the amount of clothing insulation was greatly increased. The metabolic rate fluctuated between 1.5 met and 2 met. Expectations that the wind speed in the winter would be less than 1.05 m/s were greater than expectations that the wind speed would be more than 1.05 m/s in the summer, and people generally adapted to a low wind environment with wind speeds below 1 m/s. The acceptable wind ranges for more than 90% of participants at the square and lake side were (0 m/s, 2.02 m/s) and (0.01 m/s, 2.86 m/s). This study provides support for the revision of outdoor wind comfort standards and a methodological basis for outdoor wind comfort research at the same latitude throughout the world.

A dynamic evaluation of landscape transformations based on land cover data

The present era is characterized by unprecedented levels of human activity, which adapt the world to our needs and induce transformations in landscape morphology and physiognomy. The Anthropocene is a remarkable epoch, where changes in space are not only visible, but also confirmed by an extensive body of research. Human activities lead to the creation of numerous tools for measuring the scale of anthropogenic pressure. Satellite and photogrammetric data that broaden our field of vision and change the scale of reference from local to global or even beyond global. These data support observations of the present condition of the surrounding space as well as the rate of changes in space. In the present study, land cover data were used to monitor changes in the surrounding landscape. A system for classifying evolutionary changes in space was proposed to monitor land-use transformations and describe landscape stability. The applicability of CORINE Land Cover (CLC) data for such analyses was evaluated. The research hypotheses and the proposed procedure were tested in the Mazovian (Polish: Mazowieckie) Voivodeship and the city of Warsaw, the Polish capital and the central point of the analyzed voivodeship which generates continuous changes in space. The results of the study confirmed the research hypotheses and demonstrated that CLC data are suitable for monitoring spatial changes.

Intra-annual relationship between precipitation and forest disturbance in the African rainforest

Analysis of forest disturbance patterns in relation to precipitation seasonality is important for understanding African tropical forest dynamics under changing climate conditions and different levels of human activities. Newly available radar-based forest disturbance information now enables an investigation of the intra-annual relationship between precipitation and forest disturbance in a spatially and temporally explicit manner, especially in the tropics, where frequent cloud cover hinders the use of optical-based remote sensing products. In this study, we applied cross-correlation on monthly precipitation and forest disturbance time series for 2019 and 2020 at a 0.5° grid in the African rainforest. We used the magnitude of the correlation and time lag to assess the intra-annual relationship between precipitation and forest disturbance, and introduced accessibility proxies to analyse the spatial variation of the relationship. Results revealed that a significant negative correlation between forest disturbance and precipitation dominates the study region. We found that significant negative correlations appear on average closer to settlements with overall smaller variations in travel time to settlements compared to grid cells with non-significant and significant positive correlation. The magnitude of the negative correlation increases as the travel time to settlements increases, implying that forest disturbances in less accessible areas are more affected by precipitation seasonality and that in particular human-induced disturbance activities are predominantly carried out in the drier months. Few areas showed a significant positive correlation, mainly resulting from natural causes such as flooding. These new insights in the interaction between forest disturbance, precipitation and accessibility provide a step forward in understanding the complex interactions that underlie the complexity of forest loss patterns that we can increasingly capture with Earth Observation approaches. As such, they can support forest conservation and management in coping with climate change induced changes of precipitation patterns in African rainforest countries.

Co-use of existing crossing structures along roads by wildlife and humans: Wishful thinking?

This study assesses existing human-purpose underpasses below an unfenced high-traffic 4-lane highway in the Appalachian region of Quebec, Canada, as potential crossing structures for native mammal species. Eight underpasses of three types (five water culverts with minimum height and width of 1.8 m, one low-use gravel road byway, and two railroad underpasses) were continuously monitored by motion-detection infrared camera traps for time periods spanning up to 778 days (September 2016 to November 2018). We asked how the ratios of successful crossings through the structures (termed full crossings) and aversions to the structures (termed aversions) differed between species and we explored the influence of human activity levels on the use of these structures by wildlife. All monitored crossing structures had low human observations (with averages of less than 35 human activities per day). Our results provide evidence that 21 species of mammals in the study area successfully crossed through at least one of the eight observed underpasses on a minimum of one occasion. Some species were observed crossing through some of the underpasses on a regular basis, namely raccoon, red fox, and white-tailed deer. We propose a classification of mammal species into five human co-use classes (no or low co-use to very high co-use) to explore the relationship between mammal use of the structures and human presence. We found that humans and mammals were observed sharing passages for the four mammal species identified as tolerant of human co-use (high and very high co-use classes), but co-use was observed to be limited or not occurring for most other species. The strengths of this study include the length of time during which monitoring took place, as well as the placement of four cameras at each structure (two facing inward and two facing outward) to determine whether individuals successfully crossed through the structures or displayed avoidance behaviour. The results suggest select species of mammals show some co-use with humans at existing underpasses. The activity patterns of mammals documented over the two-year study can assist with future estimates of highway permeability. Further, measurements of human and mammal co-use have species-specific implications for retrofitting existing structures and constructing wildlife fences and purpose-built wildlife passages.

Reflective Activity as a Promoter of Awareness Processes in College Students: A Study

As the literature clearly shows, supporting the development of reflective awareness skills is undoubtedly an important element in learning processes. In psychology, multiple theoretical approaches and research work have delved into the study of what is termed implicit knowledge. In particular, the relationship between human activity (in terms of actions, thoughts, beliefs, motivation, and reasoning) and different levels of awareness is a relevant subject of analysis that we consider as the core of this paper. In order to deepen our understanding of the concepts of awareness and reflexive activity, we refer to Pierre Vermersch’s psycho-phenomenological approach and Piaget’s theory of cognitive awareness. In this paper, we aim to show the use of the reflective approach centered on the elicitation of specific lived experiences. The objective is to promote in students a process of awareness of their activity and their role within the university context. Two students case studies from the University of Salerno took part in the research. The method used was based on narrative interviews that makes use of some techniques and principles of elicitation interviews, a conversational approach that supports the participant in focusing and describing a specific experience. The interviewer guides subjects, without induction, through the transition from the implicit of lived experience (particularly action) to the explicit of reflected awareness of that action. The data collected show how reflective activity by means of guided evocations of lived experiences helped participants become aware of how some distortions and irrational thoughts (related to the self and context) negatively affected them during the activities. The reflective work fostered by the elicitation of experiences often allows for enhanced self-awareness; the subject takes ownership of the action, analyzes it, and understands the difficulties.

The coupling of hillslope- and gully-erosion increases their controlling efforts: A case study in Liaoning Province, China

The widespread hillslope- and gully-erosion in Liaoning Province of Northeast China, pose serious challenges to the local agricultural production. Hillslope- and gully-erosion have typically been studied separately; however, there has been little investigation on the relationship of these two types of erosion. In this study, the coupling relationship of the hillslope- and gully-erosion from the perspectives of erosion intensity and land use, as well as the slope gradient, aspect, and shape, was analysed. The study employed remote sensing and geographic information system techniques, and the universal soil loss equation and kriging were used to perform a macroscopic analysis. The results showed that gully-erosion was more severe compared with hillslope-erosion in the study area. The cultivated land has the highest level of human activities, therefore, the most intense hillslope- and gully-erosion. The threshold slope gradients for the hillslope- and gully-erosion are 14° and 6°, respectively. Above the threshold of 6°, the slope gradient is no longer the primary factor affecting the gully-erosion. Sunny slopes have observably more hillslope-erosion than shady slopes, and the highest hillslope-erosion is observed on the south-southeast-facing slopes. The effect of the slope aspect on the gully-erosion should not be ignored, as evidenced by the considerable gully density of the east-northeast-facing slopes which is obviously higher than for slopes with other slope aspects. The highest hillslope-erosion amount and gully density occur on concave slopes, followed by convex and straight slopes, and straight slopes have little effect on the hillslope-erosion, but have a marked impact on the gully-erosion. The results of this work may serve as a scientific reference for the comprehensive control of soil erosion across a slope-gully system in Northeast China.

DIVERSITY OF POTENTIALLY TOXIC BENTHIC DINOFLAGELLATES IN INDONESIAN WATERS

Ciguatera Fish Poisoning (CFP) is a syndrome caused by ciguatoxin-producing benthic dinoflagellate, which are typically attached to macroalgae. The toxin is responsible for the human poisoning symptom observed after the consumption of contaminated reef fish. Research on the composition and abundance of benthic dinoflagellate on macroalgae had already conducted within the 2010 - 2015 at several coral reef areas in Indonesian waters, such as Weh Island - Aceh, Belitung Island, Lampung Bay, Seribu Islands, and Lombok Island. This study reviewed all the references concern on benthic dinoflagellate researches in Indonesia, with aims to raise awareness on the presence of potentially toxic benthic dinoflagellates in Indonesian waters, also to create an inventory of the species discovered. The study revealed four of the six genera which are potentially toxic, namely Amphidinium, Gambierdiscus, Ostreopsis, and Prorocentrum. The Prorocentrum cells were identified in a larger number than any other genera in all the sampling locations. The relatively high number of benthic dinoflagellates were observed in Lampung Bay and Seribu Islands, which might be due to the high level of human activities. These findings are essential to compile a database on the CFP-causing species and to monitor the affected areas, specifically in highly populated locations or tourist sites.

General theory of ensuring environmental safety: state and directions for improvement

Progress in maintaining the ecological balance at the global, regional and local levels of human activity is inextricably linked with the continuous improvement of the general theory of environmental safety. The authors believe that new successes in further research can be expected in the use of the provisions of environmental safety in the economic sphere. It was also noted that the possibilities of the culturological approach make it possible to make a great contribution to ensuring environmental safety in various fields.

Mathematical Modeling of Human Activity on Forested Areas from Point Objects of Railway Infrastructure in a Two-Dimensional Statement

Human activity causes a large quantity of wildfires in areas close to the location of different industrial or transport infrastructure. All the infrastructure facilities of JSC Russian Railways may be classified into linear, point and area sources of human activity. This work purpose is to suggest an approach for predicting, assessing, and monitoring the human activity on forested areas based on a deterministic mathematical model. Partial differential equations have been solved using the finite difference method. The program realization is executed in the RAD Studio software. Expressions like the heat conduction equation are used to describe the propagation of human activity around railway facilities. Different railway objects have produced different distribution of the virtual (possible) number of forest fires (VNF) caused by the different level of human activity. Different sizes of the railway facilities have also showed that a highest VNF is predicted for large one. The proposed mathematical model is applicable to predict wildfires due to human activity. This paper discusses the possibility of predicting forest fire dangers near point infrastructure facilities of JSC Russian Railways. The results obtained are part of a large project aimed to develop methods for predicting, assessing, and monitoring forest fire danger near infrastructure facilities of Russian Railways.

Spatial distributions and risk assessment of heavy metals and PAH in the southwestern Nigeria coastal water and estuaries, Gulf of Guinea

Spatial distributions and risk assessment of heavy metals (HM) and polycyclic aromatic hydrocarbon (PAH) in water and sediments of two southwestern Nigeria estuaries (Awoye A1-A6 and Abereke: AB1-AB7 and the adjoining coastal waters: I1–I12, C1–C7) were investigated. The physicochemical characteristics were measured in situ, while the HM and PAH were determined using atomic absorption spectrophotometer and gas chromatography coupled with flame ionization detection. The physicochemical characteristics of the water body were within the World Health Organization and United State Environmental Protection Agency stipulated limits for coastal water, except for pH (<6) and dissolved oxygen (<5 mg/l) attributed to a high level of human activities at the impacted stations (I1–I12). The HM in the water samples were within the permissible limits for coastal water bodies except for high Pb values (>1 mg/l) at the Awoye estuary linked to point source effluents of petroleum spills from downstream petroleum transportation. The calculated sediment contamination factor (CF) for HM indicated a considerable (3 < CF < 6) contamination of Cu (CF–Cu) at the sampling stations. Whereas the CF-Cr were within the moderate contamination range (1< CF < 3). The pollution load index (PLI) and ecological risk index (RI) suggest low-risk pollution of heavy metals to the aquatic ecosystems. The assessment of PAH revealed a dominant high molecular weight PAH composition in both surface water and sediments, mainly dominated by 4–6 rings PAH. The PAH diagnostic ratio BaA/(Ba + Chry) and IP/(IP + BghiP) points to the mixed (pyrogenic and petrogenic) origin of PAH across the two tropical estuaries and the coastal waters.

Evaluation of the impacts of human activities on propagation from meteorological drought to hydrological drought in the Weihe River Basin, China

Understanding the relationship among different types of drought is crucial for drought mitigation and early warnings. Much attention has been recently focused on the propagation from meteorological drought (MD) to hydrological drought (HD); however, the influences of human activities on drought propagation have rarely been explored. The novelty of the study was to propose an effective framework to quantify the impacts of human activities on MD-HD propagation. We adopted the framework to comprehensively evaluate the anthropic impacts on hydrological drought variations and time, thresholds, and probabilities of MD-HD propagation in the Weihe River Basin (WRB) during different periods. The results showed that human activities did significantly disturb HD variations and MD-HD propagation characteristics. Specifically, human activities increased the frequency and extremes of HD and weakened its correlation with MD. The MD-HD propagation characteristics showed spatiotemporal differences across three subbasins because of the different levels of human activities. The thresholds of MD triggering different levels of HD generally became larger with change rates from 1% to 143% and 3% to more than 189% during two periods, respectively. Meanwhile, we also found that the thresholds became distinctly smaller, which could only be observed in spring and winter. Moreover, the relationship between natural and human-induced probabilities of HD occurrence showed three patterns with the increase of MD severity. The quantitative results of this study can provide guide information on adaptation strategies to promote drought preparedness in the WRB. The proposed framework can be also applied in other regions to improve the understanding of hydrological drought mechanisms.