Impact Of Anthropogenic Activities Research Articles

Impacts of anthropogenic activities on eukaryotic phytoplankton communities in Panlong River via eDNA biomonitoring

Impacts of anthropogenic activities on eukaryotic phytoplankton communities in Panlong River via eDNA biomonitoring

Antibiotic resistance profile in sediments and bacterial isolates from a human-impacted mangrove from Bahía Magdalena, Mexico

Abstract Antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARG) in the environment are considered emerging contaminants. One of the ecosystems that can harbor resistant bacteria and genes is mangroves. This report aims to assess ARB and ARG's presence at two mangrove locations in Bahia Magdalena, Mexico. Bacterial isolates were selected based on their phenotypic profiles of antibiotic resistance. DNA from mangrove sediments and bacterial isolates was tested for int1 and antibiotic resistance genes by final point PCR. From 90 ARB isolates, the phenotypic profile showed resistance to ciprofloxacin (90%), cefotaxime (85.7%), and ampicillin (78.6%), while the beta-lactamase gene (blaCTX-M) was present in 72.9% of the isolates. Antibiotic resistance genes identified in sediments were found even at 30–50 cm depth, but the integron Class gen (int1) was found mainly in shallow samples. Principal component analysis showed a close relationship between the integron gene, vancomycin, and sulfonamides resistance genes. No correlation was found between the phenotypic and genotypic profiles of the bacterial isolates. Also, no differences were observed between the two mangrove ecosystems studied. The impact of anthropogenic activities was equally significant on both sites. The role of mangrove ecosystems in the dispersion of antibiotic resistance needs to be further explored.

Deciphering groundwater pollution in the Lower Anayari Catchment: insights from using δ2H, δ18O, PMF, and APCS-MLR receptor model.

This research provides a comprehensive analysis of groundwater pollution in the Lower Anayari Catchment (LAC) through δ2H and δ18O isotopic analysis, along with positive matrix factorization (PMF) and PCS-MLR receptor models. Forty groundwater samples were collected from hand-dug wells and equipped boreholes across the LAC. Flame photometry for Na+ and K+, complexometric titration for Ca2+, ion chromatography for Cl-, F-, NO3-, SO42-, and PO43-, and atomic absorption spectrometry for Mg2+, Fe, Pb, Cd, As, and Ni were analytical techniques/instruments employed. In regard to cations, Na+ has the highest average concentration of 63.0 mg/L, while Mg2+ has the lowest at 2.58 mg/L. Concerning the anions and nutrients, Cl- has the highest mean concentration of 18.7 mg/L, and Fl- has the lowest at 0.50 mg/L. Metalloids were detected in trace amount with Fe displaying the highest mean concentration of 0.077 mg/L whereas Cd and As recorded lowest (0.001 mg/L). The average values for groundwater δ18O and δ2H were - 3.64‰ and - 20.7‰, respectively; the average values for rainwater isotopic composition were - 3.41‰ for δ18O and - 17.4‰ for δ2H. It is believed that natural geological features, particularly biotite granitoid and volcanic flow/subvolcanic rocks from the Birimian Supergroup, significantly influence groundwater mineralisation. Additionally, the impact of anthropogenic activities on water quality, with urban development and agricultural practices, may be attributed to increasing levels of certain contaminants such as Fe, Ni, NO3-, and PO43-. This research contributes to the broader field of hydrological study and provides practical implications for managing and conserving water resources in similar contexts. The innovative combination of isotopic and statistical analyses sets a new standard for future studies in groundwater quality assessment, emphasising the need for comprehensive approaches that consider both geological characteristics and human impacts for sustainable water resource management.

The Impact of Anthropogenic Activities and Water Pollution on the Fish Diversity and Ecosystem Health of the Chenab River in the Punjab Region of Pakistan

Background: The Chenab River, a major waterway in the Punjab region, is subject to various anthropogenic activities that threaten its ecological integrity. Industrial discharges, agricultural runoff, and urbanization have altered the water quality and affected the river's fish diversity, raising concerns about the long-term health of the river's ecosystem and its implications for human health. Objective: This study aimed to quantify the impact of human activities and water pollution on fish diversity and ecosystem health in the Chenab River. It sought to identify significant pollutants and assess their correlations with ecological indicators. Methods: A comprehensive quantitative analysis was conducted using secondary data spanning ten years. Descriptive statistics were calculated for various environmental parameters, including industrial discharge, agricultural runoff, urbanization rate, water pH, dissolved oxygen, turbidity, and concentrations of heavy metals, nitrates, and phosphates. Correlation and regression analyses were employed to explore the relationships between these parameters and fish species richness and abundance. Results: The study revealed a mean industrial discharge of 584.43 tonnes and agricultural runoff of 290.82 tonnes. Water quality parameters fluctuated with a mean pH of 7.65 and dissolved oxygen levels averaging 8.38 mg/L. Fish species richness exhibited a mean of 49.30 with a standard deviation of 20.842, while fish abundance had a mean of 3089.16 with a standard deviation of 1256.84. Regression analysis showed dissolved oxygen as a significant predictor of fish abundance (p = .051), whereas turbidity and heavy metals had a negative impact, though not statistically significant (p = .100 and p = .092, respectively). Conclusion: The Chenab River's fish diversity and ecosystem health are influenced by anthropogenic pollution, with dissolved oxygen emerging as a critical factor for maintaining fish populations. The findings suggest a need for targeted environmental regulations to improve water quality and protect aquatic life, which is inextricably linked to human health and livelihoods.

Impact of anthropogenic activities on the accumulation of heavy metals in water, sediments and some commercially important fish of the Padma River, Bangladesh

Impact of anthropogenic activities on the accumulation of heavy metals in water, sediments and some commercially important fish of the Padma River, Bangladesh

Impact of Anthropogenic Activities on Microbial Community Structure in Riverbed Sediments of East Kazakhstan.

Heavy metal (HMe) pollution in regions with mining and metallurgy activities is known to be a serious environmental problem worldwide. Hydrological processes contribute to the dissemination of HMes (drainage, precipitation, flow rate). The aim of the present study is to investigate the microbial community structure in ten river sediments sampled in different regions of East Kazakhstan, which are contaminated with HMes. The overall degree of sediment contamination with HMes (Cr, Cu, Zn, Pb, and Cd) was assessed using the pollution index Zc, which ranged from 0.43 to 21.6, with the highest in Ridder City (Zc = 21.6) and Ust-Kamenogorsk City, 0.8 km below the dam of the hydroelectric power station (Zc = 19.6). The tested samples considerably differed in organic matter, total carbon, nitrogen, and phosphorus content, as well as in the abundance of HMe-related functional gene families and antibiotic resistance genes. Metagenomic analysis of benthic microorganisms showed the prevalence of Proteobacteria (88.84-97.61%) and Actinobacteria (1.21-5.98%) at the phylum level in all samples. At the class level, Actinobacteria (21.68-57.48%), Betaproteobacteria (19.38-41.17%), and Alphaproteobacteria (10.0-39.78%) were the most common among the classified reads. To the best of our knowledge, this is the first study on the metagenomic characteristics of benthic microbial communities exposed to chronic HMe pressure in different regions of East Kazakhstan.

Long term investigation on shoreline changes of an Island, inside a Gulf (Hormuz Island)

Shorelines, as the boundary between the body of water and the land, are influenced by different natural and anthropogenic factors. As a consequence, they are highly dynamic and are of great concern for coastal zone management. However, their behavior varies depending on their location, whether they are situated in the open ocean or within a semi-enclosed body of water. Besides, anthropogenic activities in developed beaches and/or coastal cities are the main reason for high rates of change. Thus, normally pristine and undeveloped areas are likely to experience lower rate of shoreline transformation. Hormuz Island as a typical undeveloped pristine island, with minimum anthropogenic activities in its coastlines, located inside a semi-enclosed body of water of the Persian Gulf, is the case study for this research. The alteration of the shoreline is extensively studied for 30 years. The shoreline change is analyzed using net shoreline movement, and linear regression rate indexes of the digital shoreline analysis system tool. Our findings indicated that alterations in the shoreline of Hormuz Island primarily align with natural processes, and the impact of anthropogenic activities on these changes is constrained. The average shoreline change is approximately 0.1 m/year and seldom surpasses 2.0 m/year. These outcomes align with findings observed in other undisturbed regions situated within semi-enclosed bodies of water, such as gulfs or bays. Utilizing identified shoreline alterations, our study area was categorized into three classes: dominant accretion, dominant erosion, and negligible transformation. The shore with negligible changes encompasses more than half of the island. Acknowledging the restricted variability in alterations observed in the beaches within the semi-enclosed area, there is a recognized need to develop an international classification for these types of beaches, in order to be comparable with each other all around the world.

Enterococcus Species and Their Antimicrobial Resistance in an Urban Watershed Affected by Different Anthropogenic Sources

Different anthropogenic sources can have a significant influence on bacterial populations and their antimicrobial activities. In this study, the impact of anthropogenic activities on Enterococcus species was studied in an urban watershed in southern California affected by concentrated animal feeding operations (CAFOs), recreational activities, wastewater treatment plants (WWTPs), urban runoff, and control sites. Water samples were collected quarterly for two years for the enumeration of Enterococcus species based on the Enterolert most probable-number (MPN) assay. Concentrations of enterococci were higher in the sediment compared to surface water (4.5 × 106 CFU/g of sediment vs. 2.3 × 105 MPN/100 mL of water). The species diversity was dominated by E. mundtii (32%), E. faecalis (27%), and E. faecium (25%). E. faecium exhibited the highest antibiotic-resistant phenotype. Resistances were mostly to ciprofloxacin, erythromycin, and tetracycline. Tetracycline and erythromycin resistance genes, encoded by tet (C, K, O, S) and ermB, respectively, were more common in isolates from sediment (42.9%) compared to water (12.7%). E. mundtii was sensitive to ampicillin, chloramphenicol, gentamicin, and high levels of vancomycin. A significant percentage of E. faecalis were also resistant to these antibiotics. E. faecium and E. faecalis exhibited resistance to multiple antibiotics. Our data suggest that resistant Enterococcus species within the watershed might provide some useful data to determine pollutant types and sources in that watershed. Therefore, the widespread occurrence and abundance of E. faecium and E. faecalis, and their resistance genes associated with multiple antibiotics may potentially pose risks to the local populations exposed to these water sources during recreational activities.

Loss of carbon stock as an impact of anthropogenic activities in a protected mangrove forest

Abstract. Eddy S, Setiawan AA, Taufik M, Oktavia M, Utomo B, Milantara N. 2023. Loss of carbon stock as an impact of anthropogenic activities in a protected mangrove forest. Biodiversitas 24: 6493-6501. The significant anthropogenic activities within the mangrove forest, known as the Air Telang Protected Forest (ATPF) in the Banyuasin District, South Sumatra, Indonesia, have led to an alarming degradation, leaving only its primary mangrove forests, currently constituting approximately 26% of the total forest area. This study aims to analyze changes in land cover, quantify carbon reserve loss due to CO2 emissions, and assess carbon sequestration in the ATPF over two periods: 1999-2010 and 2010-2023. Remote sensing data for 1999, 2010, and 2023 were utilized from Landsat imagery, employing ENVI and ArcGIS for land cover classification. Carbon density, CO2 emissions, and carbon sequestration were analysed using the Land Use Planning for Multiple Environmental Services (LUMENS) software. The research findings reveal an increase in the primary forest area in the first period (by almost a quarter); however, more than half of this area was lost in the second period. The secondary forest area consistently decreased over the two periods, while the open area experienced significant growth. Carbon stocks in 2010 exceeded those in 1999 due to an increase in the primary forest area, but by 2023, carbon stocks decreased significantly due to extensive land clearing. The second period witnessed the largest emissions, exceeding those of the previous period by five times. Carbon sequestration in the first period surpassed that in the second period by more than three times, with the most significant sequestration resulting from the growth of secondary mangrove forests into primary mangrove forests. The study highlights the necessity of restoration and conservation of mangrove forest areas in ATPF for sustenance of its natural function as a protected forest.

Anthropogenic impact on airborne bacteria of the Tibetan Plateau

The Tibetan Plateau is a pristine environment with limited human disturbance, with its aerosol microbiome being primarily influenced by the monsoon and westerly circulations. Additionally, the diversity and abundance of airborne microorganisms are also affected by anthropogenic activities, such as animal farming, agriculture, and tourism, which can lead to increased risks to the ecosystem and human health. However, the impact of anthropogenic activities on airborne microbes on the Tibetan Plateau has been rarely studied. In this work, we investigated the airborne bacteria of areas with weak (rural glacier) and strong human disturbance (urban building), and found that anthropogenic activities increased the diversity of airborne bacteria, and the concentration of potential airborne pathogens. Moreover, airborne bacteria in rural aerosols demonstrated significant differences in their community structure during monsoon- and westerly-affected seasons, while this pattern was weakened in urban aerosols. Additionally, urban aerosols enriched Lactobacillus sp. (member of genus Lactobacillus), which are potential pathogens from anthropogenic sources, whereas rural aerosols enriched A. calcoaceticus (member of genus Acinetobacter) and E. thailandicus (member of genus Enterococcus), which are both speculated to be sourced from surrounding animal farming. This study evaluated the impact of human activities on airborne bacteria in the Tibetan Plateau and contributed to understanding the enrichment of airborne pathogens in natural and anthropogenic background.

Impact of anthropogenic activities on bird population in Himalayan foot hills in Jammu and Kashmir

Impact of anthropogenic activities on bird population in Himalayan foot hills in Jammu and Kashmir

Impacts of anthropogenic activities and glacial processes on the distribution of chemical elements in Billefjord, Svalbard, Arctic

The Arctic region is undergoing rapid and extensive transformations due to global climate change. This study investigated the spatial distribution of 31 chemical elements in eight locations in Billefjord, Svalbard, Arctic, with varying degrees of anthropogenic and glacial influences. The west coast of Billefjord has experienced a greater historical anthropogenic impact, while the east coast has larger glaciers and shows less visible evidence of direct human impact. Over 450 topsoil samples collected in the west (abandoned mining town Pyramiden, and glacial valleys of Elsa, Ferdinand, Sven) and east coast of the fjord (glacial valleys of Ebba, Pollock, Ragnar and nearby the Nordenskiöld glacier) were extracted and analyzed by ICP-OES. The results revealed complex distributions of elements among the locations. Nordenskiöld glacier area, along with other locations in the eastern part of the Billefjord, had significantly higher levels of most elements (20 out of 31; As, B, Ca, Cd, Co, Cr, Cu, K, Li, Mg, Mo, Sb, Se, Sn, Sr, Ti, Tl, U, V, Zr). In contrast, Ferdinand Valley and other locations on the western side of the fjord had the lowest mean concentrations of most elements (18 out of 31; B, Ca, Cu, Cd, K, Li, P, Mg, Mo, Sb, Se, Sn, Sr, Ti, Tl, U, V, Zr). These findings highlight the significant influence of glacial processes on the elemental composition of soils within the region. The meltwater flow originating from glaciers in the sampled valleys contributes to the local element load, while the loss of glacier mass is associated with decreased element concentrations within these valleys. These results underscore the complexity of element distribution in the study area and emphasize the necessity for continuous monitoring efforts in this unique and environmentally sensitive region.

Assessing performance of spatial statistical stream network models in predicting alkalinity: A comparative study of two river basins in Türkiye

Developing and implementing water quality models that utilize sophisticated processes and plenty data in large river basins can be a challenging task. Factors such as sampling design, prediction at unsampled sites, and derivation of new spatial information in monitoring studies can restrict the methodologies applicable to water quality modeling. In recent years, spatial stream network (SSN) models, incorporating hydrologic distance and topological data structures, have emerged as a novel approach for predicting water quality in extensive study areas. These models have integrated conventional geostatistical methodologies and have demonstrated their effectiveness in analyzing water quality within large river basins. In this study, we aimed to investigate the feasibility of using SSN to predict alkalinity through a comparative analysis of two distinct river basins in Türkiye. We evaluated the prediction performance of SSN and the spatial characterization of the basins using spatial data sets as model components. The models are based on moving-average (MA) functions and constructed by evaluating alkalinity observations at 90 locations in Kucuk Menderes River Basin and 224 locations in the Coruh River Basin, using torgegram, correlogram, principal component analysis, and exhaustive search algorithm for covariate selection. In this research, we evaluated the optimal combination of covariates obtained from 20 different variables within the context of five spatial data set classes: topography, geology, climate, land use, and anthropology. The outcomes of the model indicate that impact of anthropogenic activities on autocorrelation based on hydrologic distance, impact of spatial covariates on variance, and root mean square prediction error (RMSPE) values of the predictions in Kucuk Menderes are more effective than those in the Coruh. The findings from the model predictions show that modeling water quality on stream network scale by using topological relationships and autocorrelation based on hydrologic distance can be recommended for rivers affected by complex and detailed processes.

The Impact of Anthropogenic Activities and Natural Factors on the Grassland over the Agro-Pastoral Ecotone of Inner Mongolia

The agro-pastoral ecotone serves as an important ecological transition zone between grassland and cropland. It plays a crucial role in providing forage and maintaining the ecological security of Northern China. China has initiated many ecological restoration projects in the agro-pastoral ecotone. Separating the affecting factors of anthropogenic activities and natural factors change on grassland may help guide future ecological restoration projects. This study investigated the grassland change over the agro-pastoral ecotone in Inner Mongolia (APEI) using land use data, vegetation index, and monthly climate data, social and economic data from 2010 to 2020. Two indicators were introduced to evaluate the grassland change in quality and quantity. The average annual maximum NDVI of grassland within each sample was used as a proxy for grassland quality, and the proportion of grassland within each sample was used as a proxy for grassland quantity. The driving mechanisms of grassland quality were examined on different types of grassland. The results showed that (1) from 2010 to 2020, the quantity of grassland in APEI slightly decreased while the quality of the grassland significantly improved; (2) the change in grassland quality was jointly caused by natural factors and human activities, with 66.77% being attributed to natural factors and 33.23% to human activities. In some areas, the alteration in grassland quality was solely determined by either the impacts of natural factors or human-induced disturbances; and (3) temperature and precipitation played different roles in affecting grassland quality among different types of grassland. In some areas, anthropogenic activities, such as farmland and population, would affect grassland quality. The findings of this study would contribute to the understanding of the mechanism of ecological environmental changes in the agro-pastoral ecotone and guide the planning and implementation of future ecological restoration projects in agro-pastoral areas.

Rapid assessment of elemental concentrations using pXRF and remote sensing on a dried lakebed

This study aimed to i) explore the land-use effect (former lakebed, pasture, and agricultural areas) on elemental concentrations, enrichment factors (EFs), and geo-accumulation indices (Igeos), ii) provide X-ray diffractograms of the primary minerals and identify the clay minerals dominant in each land-use scenario, iii) map the spatial distribution of elemental concentration, EFs, and Igeos using Digital Soil Mapping (DSM) approaches. We collected a total of 240 soil samples. Our findings highlight that vermiculite was a common clay-sized mineral, and aragonite, gypsum, and calcite were dominant primary minerals in each land-use. The remote sensing data (Sentinel-2 MSI and Landsat-8 OLI) were used to calculate some environmental covariates useful for digital mapping of elemental concentrations, EFs, and Igeos. The highest concordance correlation coefficient (CCC) was found in the prediction of Hg (CCC = 0.79) using remote sensing data based on Sentinel-2 with the Random forest (RF) model. There is neither threat in terms of Cu, Zn, and Pb nor the impact of anthropogenic activities in their distribution under each land-use scenario. The study area was enriched with Hg, Cd, and Ni (very high, EF = 20–40), followed by Cr (significant, EF = 5.88) and As (moderate, EF = 2.08). A similar trend was also found for Igeos across the study area. We conclude that the distribution of elemental concentration, EFs, and Igeos were significantly affected by the shrinking of the Burdur Lake and the different land-use scenarios in this semi-arid region.

MORPHOLOGICAL INDICATORS OF THE NARROW-CRUSTED VOLE OF THE ANTHROPOGENIC TERRITORY OF NORTH-EASTERN KAZAKHSTAN

This study delves into the intricate relationships between ecological factors, adaptation, and the effects of anthropogenic activities on small mammals in the Northeastern region of Kazakhstan. External traits, including body mass, length, tail length, ear height, and hind foot length, provide valuable insights into adaptive adjustments in response to various climatic and ecological conditions. Industrial areas reveal a reduction in average body mass, attributed to patchy vegetation and proximity to factories and roads. Size variations are closely tied to food availability, with a reduction in body size and growth rates observed in technogenic zones. Tail sizes differ by age and sex, while foot sizes tend to even out as animals mature. Notably, anthropogenic pollution has minimal impact on ear length. The heart index reflects an individual’s mobility and thermoregulation, while the liver index is influenced by food availability and energy resources. Notably, the analysis extends beyond average differences, considering the range of variability to identify increased diversity, even in ecologically challenging areas. Small mammals exhibit a high metabolic rate and limited physiological stress adaptability, yet the population demonstrates remarkable adaptation. Enlarged heart indices suggest increased locomotor activity associated with overcoming anthropogenic barriers, such as railways and highways. In addition to heart indices, liver mass calculations reflect the accumulation of energy reserves and materials for growth. The study highlights that the liver mass index of field mice in industrial zones exceeds that of the control group, indicating the impact of anthropogenic activities on these organisms. This research provides valuable insights into the intricate relationships between ecological factors, adaptation, and human influence on small mammal populations in the Northeastern region of Kazakhstan. Keywords: small mammals, narrow-crusted vole, morphophysiological indicators method, exterior signs, interior signs.

Habitat suitability of four threatened Himalayan species: Asiatic black bear, common leopard, musk deer, and snow leopard.

Biodiversity conservation is becoming challenging day by day. For this, it is essential to understand the distribution, habitat, and impact of anthropogenic activities on animals at risk. We assessed the suitable habitats and anthropogenic impacts on Asiatic black bears, common leopards, musk deer, and snow leopards in and outside the protected areas of Gandaki Province, Nepal. We collected the presence locations of Asiatic black bears, common leopards, musk deer, and snow leopards based on scats and other signs. We employed the Maximum Entropy (MaxEnt) tool to identify suitable habitats of our studied species and their anthropogenic impacts on them. The total suitable habitat of the common leopard was found to be 6,052 km2, followed by the Asiatic black bear (5,819 km2), snow leopard (4,447 km2), and musk deer (1,690 km2) in Gandaki Province. Most of the areas of suitable habitat for common leopards and Asiatic black bears were outside the protected areas, and for musk deer and snow leopards were inside the protected areas. Elevation was the most important variable determining habitat suitability of Asiatic black bear, common leopard, and musk deer, whereas the distance to water was the most important variable determining habitat suitability of snow leopard. Asiatic black bears, common leopards, and musk deer face significant anthropogenic impacts, but snow leopards face some anthropogenic impacts. Managing these animals' habitats inside and outside protected areas is essential. Hence, biodiversity conservation and livelihood opportunities should be balanced in the Himalayas on a win-win basis.

A comprehensive observation on the pollution characteristics of peroxyacetyl nitrate (PAN) in Beijing, China

Peroxyacetyl nitrate (PAN) is a typical secondary photochemical product in the atmospheric environment with significant adverse effects on human health and plant growth. In this study, PAN and other pollutants, as well as meteorological conditions were observed intensively from August to September in 2022 at a typical urban sampling site in Beijing, China. The mean and maximum PAN concentrations during the observation period were 1.00 ± 0.97 ppb and 4.84 ppb, respectively. Severe photochemical pollution occurred during the observation period, with the mean PAN concentration about 3.1 times higher than that during the clean period. There was a good positive correlation between O3 and PAN, and their correlation was higher during the O3 exposure period than that during the clean period. The simulated results by box-model coupled with the Master Chemical Mechanism (MCM v3.3.1) showed that the O3-related reactions were the largest sources of OH radicals during O3 exposure period, which was conducive to the co-contamination of PAN and O3. Acetaldehyde (CH3CHO) and methylglyoxal (MGLY) were the largest OVOCs precursors of peroxyacetyl radicals (PA), with the contributions to the total PA generated by OVOCs about 67 % – 83 % and 17 % – 30 %, respectively. The reduction of emissions from liquefied petroleum gas (LPG) and solvent usage has the highest reduction effect on PAN and O3, followed by the control of gasoline vehicle exhaust emissions. This study deepens the understanding of the PAN photochemistry in urban areas with high O3 background conditions and the impact of anthropogenic activities on the photochemical pollution. Meanwhile, the findings of this study highlight the necessity of strengthening anthropogenic emissions control to effectively reduce the co-contamination of PAN and O3 in Beijing in the future.

Heavy Metal Assessment in Water, Sediment and Biota from Ennore Creek and Vellar Estuary, Southeast India

The impact of anthropogenic activities on the accumulation of heavy metals in water, sediment and fish of both Ennore creek and Vellar estuary were observed in this study. Water and sediment sample were collected from both sampling stations and fish was collected just from only Ennore creek. Sediment and fish samples were subjected to a total digestion technique (HNO3 – HCl – HF conc.) and analysed using a spectrophotometer. Four elements Cu, Cd, Zn and Pb (trace elements) were determined. Heavy metal concentration of Ennore creek was significantly higher than the concentration of samples from Vellar estuary. The order of metal levels in water sample from Ennore creek is Cu > Zn > Cd > Pb and the sequence order of Vellar estuary water sample is Zn > Pb > Cu > Cd. The concentration of heavy metals in the sediment samples of Ennore creek showed in the following sequential order: Zn > Cu > Pb > Cd and the sequence order of Vellar estuary: Zn > Cd > Cu > Pb. In the Ennore creek, the accumulation of Zn in the muscle tissue is observed in the order, O. mosambique (7.3mg/g), M. cephalus (7.13mg/g) and A. djedaba (6.76 mg/g). M. cephalus showed high levels of Cu (5.25 mg/g) followed by A. djedaba (4.63mg/g) and O. mosambique (4.24mg/g). Based on the overall average of heavy metals present in different organs of the fish samples, trend of metal accumulation in different organs are observed as follows: Cu: Muscle > liver > gills and Zn: Muscle > liver > gills.

Is body condition of Mexican rubyspot (Odonata:Zygoptera) associated with urbanization?

Urbanized areas can impose selective pressures on insects which can be identified at the individual level based on animal physiological condition. Physiological condition can be measured from variables such as body size, body mass or energetic budget of individuals. We examined whether body mass, wing spot size and energy reserves (proteins, lipids and carbohydrates) were reduced as urbanization increases, using adults of two damselflies, Hetaerina americana and H. vulnerata, in Central Mexico. We used a Habitat Integrity Index to assess the degree of urbanization in our sampled sites, considering biophysical attributes and the impact of anthropogenic activities. We did not find relation of above individual variables with urbanization degree. These results support possible resilience of rubyspot damselflies in the face of radical changes such as urbanization. Our finding echoes other results in damselflies research.Implications for insect conservationOur results highlight the resilience of these damselflies species in the face of urban disturbances. Thus design cities considering not only requirements of humans is essential to promote the presence and conservation of these and other species of insects in cities.Graphical abstract