Otolith microchemistry of freshwater indigenous minor carp (Bangana dero) as a biomonitoring tool to trace heavy metals in River Sutlej, Ropar Wetland (Ramsar site), Punjab, India

The elemental composition of the fish otolith may represent a permanent record of the environmental condition the fish inhabited. Fish otolith grows incrementally from the core to a marginal region that acts as a repository of trace metal signatures. The present study explores the potential application of otolith microchemistry of the benthopelagic indigenous minor carp Bangana dero sampled from the Ropar wetland on River Sutlej, Punjab. The concentration of sixteen metals was evaluated in the otolith (n = 42) and water (n = 48) for the post-monsoon and pre-monsoon season from 2020 to 2022 using inductively coupled plasma mass spectrometry (ICP-MS) followed by element detection in the core and marginal region of whole otolith, using energy-dispersive mass spectroscopy (EDS). All the heavy metals exhibited an increase in metal concentrations in fish otolith than water during the post-monsoon season. By indices approach, the otolith was found to have a high bioaccumulation factor for Se in the post-monsoon and Hg in the pre-monsoon. Certain trace metals like As and Hg exhibited fluctuations in their core and marginal region. Thus, trace metal patterns in the otolith could act as a potential tool for monitoring the seasonal changes of metals in water bodies. The EFHg, EFSe and EFAs in the fish otolith predicted its anthropogenic source, while the remaining studied elements showed ambient water origin. Thus, using the otoliths of Bangana dero as a long-term monitoring tool in the future may be helpful for environmental assessments and the reconstruction of historical exposure for safeguarding of water bodies.

Assessment of industrial effluents for heavy metals concentration and evaluation of grass (Phalaris minor) as a pollution indicator

This study was conducted to investigate the impact of industrial activities on heavy metals status in wastewater, sludge and flora on the bank of selected main drains of the Hayatabad Industrial estate, Peshawar. Plants, sludge and wastewater samples of selected sites were collected and analyzed for heavy metals distribution; cadmium (Cd), chromium (Cr), lead (Pb) and zinc (Zn) levels. Bioconcentration factor (BCF) values were calculated for plants (Phalaris minor) grass species found naturally at all sites. The results showed that the levels of metals in wastewater were lower than permissible limits except Cd and the concentration of metals in plants and sludge were within permissible limits when compared to their respective standards. Metal distribution was in the following order; sludge > plants > wastewater and the concentration of metals varied according to the distance from the source with no specific pattern. Sludge samples for all sites showed a high concentration of metals as compared to plants and wastewater samples. In grass samples, Zn was highest and Cd was low for all sites. Metals accumulation in plants was in order of; roots > shoot. Pearson's coefficient correlation showed that Cr in plant roots and Zn in shoots showed significantly high correlation with Cd in sludge while Pb in roots showed significant negative correlation with Zn in sludge. BCF values for Cr, Pb and Zn were >1, showing the phytoremediation potential of plants.

Bio-transfer and bioaccumulation patterns of heavy metals in mine site-inhabiting ants and grasshoppers, across mine site restoration chronosequence

Soil is known to serve as a significant sink for heavy metals in coal mine sites, thus also influence the plant and other organisms of that area. Hence, the presence of heavy metals in coal mine soil is of concern to land managers. Insects occupy different trophic positions in the food chains, thus many insect species accumulate large amounts of heavy metals in their bodies and this is a matter of concern. In the present study, we investigated biotransfer and bioaccumulation of heavy metals from soil, grass species Cynodon dactylon, Vetiveria zizanioides, grasshopper species Gastrimargus africanus, Choroedocus robustus, ant species Cataglyphis longipedem and Camponotus compressus in six different ages (2, 4, 6, 8, 10 and 12 year old) of coal mine sites. Our study revealed that at some extent the heavy metal content and BAF patterns of heavy metals along different pathways (from soil to grass, soil to grasshoppers and from grass to grasshoppers) were not consistent and did not reflect the soil pollution status for all the metals, related to the mine spoil dump age. However, in contrast, ants successfully reflected a consistent pattern in the bioaccumulation of heavy metals via soil, thereby indicating the pollution status of the soil along with the restoration age of mine spoil dumps. Our study showed that ant species can successfully forecast the presence of heavy metals of coal mine spoils along with their restoration.

Evaluation of pollution indicators and transported sediment content in agricultural drainage waters for reuse as irrigation, Harran Plain, Turkey

The aim of this study is to determine the variation of certain pollution indicators and the level of sediment carried within drainage channel discharge waters following irrigation of fields on the Harfran Plain during the irrigation season. In this context, water samples were taken from 27 stations in total, including 26 drainage channels and 1 irrigation water channel (reference point), for 6 months between May 2020 and October 2020, and determined parameters were measured. Areal distribution maps were prepared with the ArcGIS program in order to better visually present the pollution level across the plain with the obtained data. The monthly changes of the analysis parameters and the significance level of the differences between the stations were determined using ANOVA analysis and the correlations between the measured parameters were determined using the Pearson correlation matrix SPSS package program. Evaluated on the basis of these areal distribution maps, it can be seen that the agricultural drainage waters of the Harran Plain are not suitable for irrigation in terms of five pollution indicators (pH, conductivity (EC), turbidity (Turb), sodium (Na⁺), and nitrate (NO₃^-)). Some sampling points in terms of pH (D9, R), conductivity (D10, D20), turbidity (all points) and Na + (as sodium adsorption rate) (D20) are in the "high usage restriction" category. In terms of conductivity, five points (D12, D13, D14, D15, D18); all points in terms of bicarbonate (HCO₃^-); and three points (D10, D12, D18) in terms of Na⁺ (as SAR) are classified as "low-medium usage restriction". According to the One-way ANOVA test performed to determine the differences between the points, there is a significant difference (p < 0.05) between the sampling points for all the following values: EC, dissolved oxygen (DO), Turb, Na⁺, HCO₃^-, chloride (Cl^-), sulphate (SO₄^2-), NO₃^-, pH, and transported sediment (TS), within the 95% confidence interval. In the test performed to determine the differences between the months, at the 95% confidence interval there is a significant difference (p < 0.05) between the months for parameters such as water temperature (WT), pH, DO, Turb, HCO₃^-, NO₃^-, and TS. There is a strong positive correlation between EC and Na⁺, Cl^-, and NO₃^- (r = 0.785-0.915) and Turb and TS (r = 0.725). With regard to sustainable agricultural practice for the plain, it is thought that the obtained results will contribute to administrative decision-making at a variety of management levels.

Feeding habit and pollution indicating food items of Mystus gulio (Hamilton, 1822) in the inward waters of Mumbai coast

The study considered factors related to feeding habits such as food, frequency of occurrence (F), feeding index (IA) and vacancy index (VI). The aim was to determine the relationship between the feeding habits of a non-selective, euryphagous, voracious and pollution-tolerant fish species in a contaminated habitat. The seasonal food and feeding pattern of Mystus gulio, long whiskered catfish, from Ulhas river estuary and Thane Creek analysed from stomach content depicted the pollution status of the ambient environment based on the feeding pattern using box-whiskered plot, MDS and cluster analysis. Coconut husk fibres, eggshells, chicken feathers, pieces of brick, sand particles, plastic fibres, etc., represented the non-food component of anthropogenic origin. The presence of non-food items indicates the severely degraded conditions in the study areas, especially in Thane Creek. Although a native fish species tolerant of pollution, the survival of M. gulio in Thane Creek is threatened.

Potential health risk assessment of contaminants in soil-like material recovered from landfill mining

Landfill mining is an innovative technique to clear dumpsites and recover valuables from legacy waste. Bio-earth, referred here as soil-like material, constitutes a major portion of the legacy waste fraction. The characterisation of Soil Like Material from Ariyamangalam Dumpyard and estimation of pollution indices by comparing with the background soil helps in the identification of the contamination level. The potential health risk associated with the contaminants in Soil Like Material is highlighted. A statistical correlation was also done for various parameters of Soil Like Material to identify the indicator element through the Spearman rank correlation method. The degree of contamination based on eight heavy metals taken into account shows a value of 48.23, which is in the range of very high contamination. The major pollution is induced by the lead present in the Soil Like Material compared to the background soil, followed by chromium and zinc. Lead shows the maximum contamination factor of 19, pollution index of 23.3, geo-accumulation index of 4.2 and enrichment factor of 19. The hazard index is in the order of Cr > Pb > Cu > Ni > Cd > Zn > Hg > As for the heavy metals. Among all heavy metals, the cumulative cancer risk is more due to nickel (0.06 and 0.006 for children and adults, respectively) which is harmful to human health. Hexavalent chromium was found to be an indicator element by significantly correlating with four other parameters. The results of the health risk assessment (HRA) and pollution indices add value to the application of Soil Like Material fractions both onsite and offsite.

Sexual hormones in a coastal river adjacent to the Bohai Sea: Characteristic pollutants and dominantly influencing factors

Characteristic sexual hormones (SHs) and the factors that dominantly influence their occurrence in coastal ecosystems are less understood. This study verified the relationships between SHs and environmental factors and further inferred the possible controlling mechanisms of SH distribution. A characteristic pollutant of SHs was first proposed by determining the contamination level and ecological risks of SHs (seven species) in a coastal river adjacent to the Bohai Sea. The results showed that the 17β-oestradiol (17β-E2), estriol (E3), and 17α-ethynylestradiol (EE2) had high mean concentrations of 11.20 (±1.31), 10.17 (±4.91), and 16.71 (±0.88) ng L^-1, respectively, in the river water. The concentration of estrone (E1) was positively related to microbial substances of DOMs (p < 0.05). The humification index (HIX) had a negative relationship with E3 (p < 0.05). In water, the distribution of total SHs was regulated by the HIX and fluorescence index (FI), which might be related to photodegradation reactions. The 17α-oestradiol (17α-E2) and EE2 were related to humified organic matter, while E3 and androstenedione (ADD) were influenced by sewage input. The 17β-E2, E1, and 17α-E2 may be derived from animal sources, while E3, ADD, EE2, and progesterone were from human activities. Oestrogens, including E1, 17α-E2, 17β-E2, and EE2, displayed higher ecological risks than androgens and progesterone, with medium to high risk in most sites. The 17β-E2 was regarded as a characteristic pollutant of SHs throughout the river system, which displayed the highest risk. This paper may provide a reference for SH risk management and control.

Using magnetic susceptibility to evaluate pollution status of the sediment for a typical reservoir in northwestern China

Intensive anthropogenic activities may add to pollution risks to lakes and rivers, which can be revealed by the magnetic characteristics of sediments. The present study aims to assess the pollution status of the sediment of a typical reservoir in northwestern China by application of magnetic susceptibility. The values of magnetic susceptibility exhibited significant positive correlations with trace metals (Co, Cu, Mn, Ni, and V) and natural radionuclides (²³²Th and ⁴⁰K). Multivariate statistical analysis indicated common sources and similar deposition characteristics of magnetic particles and trace metals. It was conformed that magnetic susceptibility could be used as an indicator to identify industrial sources of trace metals, but was not suitable to indicate the traffic or natural sources. Linear regression equations between the low-frequency magnetic susceptibility and the integrated pollution index as well as annual effective dose rate indicated a potential for using magnetic susceptibility in semi-quantitative assessment of trace metal pollution and radiological hazard in sediments. A three-step procedure is proposed for the use of magnetic susceptibility in pollution monitoring, which provides a fast and effective method for estimating the pollution extent and tracing the major sources of trace metals in the sediment of lakes and rivers.

Cilioprotists as biological indicators for estimating the efficiency of using Gravel Bed Hydroponics System in domestic wastewater treatment

Interest has increased over the last several years in using different methods for treating sewage. The rapid population growth in developing countries (Egypt, for example, with a population of more than 87 millions) has created significant sewage disposal problems. There is therefore a growing need for sewage treatment solutions with low energy requirements and using indigenous materials and skills. Gravel Bed Hydroponics (GBH) as a constructed wetland system for sewage treatment has been proved effective for sewage treatment in several Egyptian villages. The system provided an excellent environment for a wide range of species of ciliates (23 species) and these organisms were potentially very useful as biological indicators for various saprobic conditions. Moreover, the ciliates provided excellent means for estimating the efficiency of the system for sewage purification. Results affirmed the ability of this system to produce high quality effluent with sufficient microbial reduction to enable the production of irrigation quality water.

Macrobenthos and multi-molecular markers as indicators of environmental contamination in a South American port (Mar del Plata, Southwest Atlantic)

We evaluated benthic habitat quality along a presumed contamination gradient in the Mar del Plata port (Southwestern Atlantic) by coupling biological and chemical proxies in a multidisciplinary approach. Organic matter and photosynthetic pigment contents were higher in silty-clay bottoms of the inner port sites. Levels of all fecal steroids decreased from the inner sites to the port inlet. High concentrations of coprostanol in the inner sites seemed to derive from a permanent population of sea lions rather than from sewage outfalls due to coprostanol/epicoprostanol ratio (IV) values <2.5. PAHs levels were also higher in the inner sector, related to both biomass combustion and petroleum combustion associated to local marine traffic. High disturbance and low ecological status were reflected in low benthic diversity and high AMBI values in the inner sites.