Toxic Metal Pollution in Pakistan and Its Possible Risks to Public Health

Investigating the teratogenic potential of diclofenac sodium on chick embryos: A warning for pregnant women

Teratogenic and embryotoxic effect of diclofenac sodium (DS) on different developmental stages of the chick-embryos was investigated by examining different parameters such as its mortality rate, hatching, morphological measurements, weighing its internal organs and calculation of different indices. Experiment was divided into four trials with different dose (0.1 mL, 0.2 mL, 0.3 mL in groups A, B, and C, respectively and group D received 0.3 mL saline solution (0.9% NaCl) and group E remained un-injected) administration and observation. Results of first and second trial showed statistically (p<0.01) significant difference in bodyweight, body-length, forelimb and hindlimb length between experimental and control groups. In third trial, diclofenac sodium administration showed a statistically (p<0.01) significant difference in the bodyweight, body-length, forelimb, hindlimb length, liver weight, egg weight (EE ratio) and kidney somatic index (KSI). The beak-size, heart weight, kidney weight, cardiac somatic index (CSI) and hepato somatic index (HSI) were not significant (p>0.05) when compared with the control groups. In trial 4, forelimb, hindlimb length, heart weight, CSI and HSI were statistically (p<0.01) significant. Body-length and liver weight were significant (p<0.05). While bodyweight, beak size, kidney weight and KSI were non-significant (p>0.05). The mortality rate was increased with increase dose of DS and also affected the hatching. DS effect on chick embryos can be applied to humans because the early development of mammals and birds are closely related. So, it was concluded that DS should be used with caution during pregnancy especially during first trimester of pregnancy.

Trace metals and nutrient analysis of marine fish species from the Gwadar coast

Trace metals are naturally occurring metals found in very small concentrations in the environment. In the context of fish flesh, metals such as copper, calcium, potassium, sodium, zinc, iron, and manganese are absorbed by fish and play vital roles in various physiological functions. However, if these metals exceed the recommended limits set by WHO/FAO, they are termed 'toxic metals' due to their harmful impacts on both the fish and its consumers. Therefore, the present study aims to analyze the levels of protein, lipids, and certain metals-Aluminum (Al), Sodium (Na), Zinc (Zn), Titanium (Ti), Iron (Fe), Copper (Cu), Potassium (K), and Calcium (Ca) in three commercially important marine fishes i.e. Rastrelliger kanagurta, Sardinella abella, and Otolithes ruber. The study also aims to assess their potential impact on human health. The macro-Kjeldhal method and Soxhlet apparatus were used to estimate protein and lipid contents, while atomic absorption spectroscopy (AAS) was used to estimate trace metals found in fishes. The study found that these fish species are valuable sources of protein, lipids, and certain essential minerals. The protein content (CP) in these three species ranged from 63.35 to 86.57%, while lipid content was from 21.05 to 23.86%. The overall results of the trace metal concentrations analyzed in the present study revealed that Aluminum (Al), Sodium (Na), Zinc (Zn), Titanium (Ti), Copper (Cu), Potassium (K), and Calcium (Ca) were found in low concentration or traces and also within suitable ranges as set by WHO/FAO. However, Iron (Fe) was absent in all three species. Moreover, both copper and potassium were found in all three species, while Zinc was present in Rastrelliger kanagurta and Sardinella abella, calcium in Sardinella abella, and sodium in Otolithes ruber only. Titanium was recorded for the first time in S. abella. However, the total health risk assessment associated with these fish food consumption was measured by THQ and TTHQ and found to be less than 1, which shows no potential risk related to trace metals found in these fishes on human health upon their consumption. In conclusion, these commercially important marine fish species were found valuable sources of protein, lipids, and essential trace minerals that are necessary for human health. Thus, the current study provides useful information for the local population to make informed decisions about their daily diets and highlights the importance of sustainable fishing practices to maintain these valuable marine resources by periodical monitoring of their ecosystem.

The detrimental effects of heavy metals on tributaries exert pressure on water quality, Crossocheilus aplocheilus, and the well-being of human health

The escalating presence of heavy metals (HMs) in the Panjkora River water and their impact on fish pose a significant challenge to both the ecological community and human health. Consequently, a study was conducted with the primary aim of elucidating their influence on human health-related issues. To address this, the concentrations of heavy metals, including arsenic (As), cadmium (Cd), iron (Fe), manganese (Mn), lead (Pb), and zinc (Zn), in both water and the fish species Crossocheilus diplocheilus were investigated across various locations within the study area. The quantification of HMs concentration was carried out utilizing an atomic absorption spectrophotometer. The highest concentration in water was found as 0.060 mg/L for Pb and lowest for Fe, whereas the highest concentration in fish was 2.028 mg/kg for Pb and lowest for As. Human health risk associated with fish eating was evaluated by using health risk indices (HRI) for non-carcinogenic health risks and targeted cancer risk (TR) for carcinogenic health risks. The values of the health risk index (HRI) were found greater than 1 except Fe (0.0792), Zn (0.782), and Mn (0.541). The highest mean HRI > 1 was recorded for As (62.99), Cd (26.85), and Pb (10.56). This implies that fish consumption from river Panjkora is not safe up to some extent. Similarly, the TR value for As, Cd, and Pb was found 2.8 [Formula: see text], 1.6 [Formula: see text], 2.8 ×[Formula: see text] which showed cancer risk. There is a detected risk to human health associated with the consumption of fish from the Panjkora River. The government must implement adaptive measures to address this significant issue of water pollution in the study area. Additionally, there is a need for further extensive and prolonged research studies in this context.

Assessment of soil heavy metal pollution and associated ecological risk of agriculture dominated mid-channel bars in a subtropical river basin

The elevated concentrations of heavy metals in soil considerably threaten ecological and human health. To this end, the present study assesses metals pollution and its threat to ecology from the mid-channel bar's (char) agricultural soil in the Damodar River basin, India. For this, the contamination factor (CF), enrichment factor (EF), geoaccumulation index (I_geo), pollution index, and ecological risk index (RI) were measured on 60 soil samples at 30 stations (2 from each station, i.e., surface and sub-surface) in different parts of the mid-channel bar. The CF and EF indicate that both levels of char soil have low contamination and hence portray a higher potential for future enrichment by heavy metals. Moreover, I_geo portrays that soil samples are uncontaminated to moderately contaminated. Further, pollution indices indicate that all the samples (both levels) are unpolluted with a mean of 0.062 for surface soils and 0.048 for sub-surface soils. Both levels of the char have a low potentiality for ecological risk with an average RI of 0.20 for the surface soils and 0.19 for the sub-surface soils. Moreover, Technique for order preference by similarity to ideal solution (TOPSIS) indicates that the sub-surface soils have lower pollution than the surface soils. The geostatistical modeling reveals that the simple kriging technique was estimated as the most appropriate interpolation model. The present investigation exhibits that reduced heavy metal pollution is due to the sandy nature of soils and frequent flooding. However, the limited pollution is revealed due to the intensive agricultural practices on riverine chars. Therefore, this would be helpful to regional planners, agricultural engineers, and stakeholders in a basin area.

Health risk assessment and bioaccumulation of potentially toxic metals from water, soil, and forages near coal mines of district Chakwal, Punjab, Pakistan

Water, forages, and soil contamination with potentially toxic metals (PTMs) through anthropogenic activities has become a significant environmental concern. It is crucial to find out the level of PTMs in water, soil, and forages near industrial areas. The PTMs enter the body of living organisms through these sources and have become a potential risk for humans and animals. Therefore, the present study aims at the health risk assessment of PTMs and their accumulation in soil, water, and forages of three tehsils (Kallar Kahar, Choa Saidan Shah, and Chakwal) in district Chakwal. Samples of wastewater, soil, and forages were collected from various sites of district Chakwal. PTMs detected in the present study were cadmium (Cd), chromium (Cr), lead (Pb), zinc (Zn), cobalt (Co), copper (Cu), and nickel (Ni), and their levels were measured through atomic absorption spectrophotometer (AAs GF95 graphite furnace auto sampler). Pollution load index (PLI), bio concentration factor (BCF), soil enrichment factors (EF), daily intake value (DIM), and health risk index (HRI) in sheep, cow, and buffalo were also analyzed. The results revealed that the mean concentration (mg/L) of Cd (0.72-0.91 mg/L), Cr (1.84-2.23 mg/L), Pb (0.95-3.22 mg/L), Co (0.74-2.93 mg/L), Cu (0.84-1.96 mg/L), and Ni (1.39-4.39 mg/L) in wastewater samples was higher than permissible limits set by WHO, NEQS, WWF, USEPA, and Pakistan in all three tehsils of district Chakwal. Similarly, in soil samples, concentrations of Cd (1.21-1.95 mg/kg), Cr (38.1-56.4 mg/kg), and Ni (28.3-55.9 mg/kg) were higher than their respective threshold values. The mean concentration of PTMs in forage samples (Parthenium hysterophorus, Mentha spicata, Justicia adhatoda, Calotropis procera, Xanthium strumarium, Amaranthaceae sp.) showed that maximum values of Cd (5.35-7.55 mg/kg), Cr (5.47-7.51 mg/kg), Pb (30-36 mg/kg), and Ni (12.6-57.5 mg/kg) were beyond their safe limit set for forages. PLI, BCF, and EF were > 1.0 for almost all the PTMs. The DIM and HRI for sheep were less than < 1.0 but for cows and buffalo were > 1.0. The current study showed that soil, water, and forages near coal mines area are contaminated with PTMs which enter the food chain and pose significant harm to humans and animals. In order to prevent their dangerous concentration in the food chain, regular assessment of PTMs present in soil, forages, irrigating water, and food is recommended.

Biomonitoring of heavy metals in the feathers of House crow (Corvus splendens) from some metropolitans of Asia and Africa

Urban-dwelling birds can be useful biomonitors to assess the impact of the urbanisation on both public and wildlife health. Widely distributed urban bird species, the House crow, was studied for heavy metal accumulation levels from nine cities of South Asia, Southeast Asia and Africa that border the Indian Ocean. Feathers were spectroscopically investigated for the deposition of ten heavy metals, i.e. As, Zn, Pb, Cd, Ni, iron Fe, Mn, Cr, Cu and Li. Fe and Zn were found to be the most prevalent metals in all sites. Measured concentrations of Pb (4.38-14.77 mg kg^-1) overall, and Fe (935.66 mg kg^-1) and Cu (67.17 mg kg^-1) at some studied sites were above the toxicity levels reported lethal in avian toxicological studies. Multivariate analysis and linear models supported geographical location as a significant predictor for the level of most of the metals. Zn and Cu, generally and Pb, Cd, Mn, Cr at some sites exhibited potential bioaccumulation from surrounding environments. Inter-species comparisons strengthen the inference that the House crow is a reliable bioindicator species for the qualitative assessment of local urban environmental pollution and could be a useful tool for inter-regional monitoring programs.

Assessment of water quality, trace metal pollution, source apportionment and health risks in the groundwater of Chakwal, Pakistan

Groundwater quality evaluation is the main concern in the regions like Chakwal where it is major source of water for drinking and irrigation due to low storage capacity of the surface water and lack of proper irrigation system. The aim of the present study was to evaluate various physicochemical parameters (pH, EC, TDS, DO, TA, TH and chlorides) and selected essential/toxic trace metal concentrations (Na, K, Ca, Mg, Sr, Li, Ag, Zn, Fe, Cu, Co, Mn, Cr, Cd, and Pb) in order to explore their distribution, correlation, spatial variations and health risk assessment. Average concentration of some trace metals (Co, Cd and Pb) and physicochemical parameters (EC, TDS, and alkalinity) were found to exceed the national/international standards. Multivariate methods of analysis showed strong associations among Fe-Li-K, Sr-Mg-Ca, Cd-Mn, Cu-Zn, Ag-Co, and Cr-Pb-Na which were significantly contributed by anthropogenic activities. Irrigation water quality index exhibited intermediate suitability of the groundwater for irrigation purpose. Health risk evaluation of the trace metals revealed significant non-carcinogenic risks for Cd, Co and Pb (HQ_ing > 1) especially for children. Similarly, significant carcinogenic risk was found to be associated with Pb and Cr which exceeded the safe limit, suggesting the lifetime carcinogenic risk associated with these metals in the groundwater. The present health risk problems should be considered on top priority and immediate actions should be taken to safeguard the water quality in the study area.

Urinary metals, arsenic, and polycyclic aromatic hydrocarbon exposure and risk of chronic bronchitis in the US adult population

Metals, arsenic, and polycyclic aromatic hydrocarbons (PAHs) have all been linked to respiratory diseases. Chronic bronchitis, which is a form of chronic obstructive pulmonary disease (COPD), is a major public health concern and source of morbidity and mortality in the US. The purpose of this study was to analyze the correlation of 14 urinary metals (antimony, barium, cadmium, cesium, cobalt, lead, manganese, mercury, molybdenum, strontium, thallium, tin, tungsten, uranium), seven species of arsenic, and seven forms of polycyclic aromatic hydrocarbon (PAH) concentrations and chronic bronchitis in the US population. A cross-sectional analysis using three datasets from the National Health and Nutrition Examination Survey (NHANES) between 2011 and 2016 in adults, aged 20 years and older. Chronic bronchitis was determined using a self-questionnaire from the NHANES dataset. A specialized weighted complex survey design analysis package was used to analyze NHANES data. Multivariate logistic regression models were used to determine the correlation between urinary metals, arsenic, PAHs, and chronic bronchitis. Models were adjusted for lifestyle and demographic factors. A total of 4186 participants were analyzed; 49.8% were female and 40.5% were non-Hispanic White. All seven types of PAHs showed a positive association with chronic bronchitis (1-hydroxynaphthalene odds ratio (OR): 1.559, 95% confidence interval (CI): 1.271-1.912; 2-hydroxynaphthalene OR: 2.498, 95% CI: 1.524-4.095; 3-hydroxyfluorene OR: 2.752, 95% CI: 2.100-3.608; 2-hydroxyfluorene OR: 3.461, 95% CI: 2.438-4.914; 1-hydroxyphenanthrene OR: 2.442, 95% CI: 1.515-3.937; 1-hydroxypyrene OR: 2.828, 95% CI: 1.728-4.629; 2 & 3-hydroxyphenanthrene OR: 3.690, 95% CI: 2.309-5.896). Of the metals, only urinary cadmium showed a statistically significant positive association (OR: 2.435, 95% CI: 1.401-4.235) with chronic bronchitis. No other metals or arsenic were correlated with chronic bronchitis. Seven forms of urinary PAHs, cadmium, and several demographic factors were associated with chronic bronchitis.

Pollution characteristics and human health risk assessments of toxic metals and particle pollutants via soil and air using geoinformation in urbanized city of Pakistan

Toxic metals and particle pollutants in urbanized cities have significantly increased over the past few decades mainly due to rapid urbanization and unplanned infrastructure. This research aimed at estimating the concentration of toxic metals and particle pollutants and the associated risks to public health across different land-use settings including commercial area (CA), urban area (UA), residential area (RA), and industrial area (IA). A total of 47 samples for both soil and air were collected from different land-use settings of Faisalabad city in Pakistan. Mean concentrations of toxic metals such as Mn, Zn, Pb, Ni, Cr, Co, and Cd in all land-use settings were 92.68, 4.06, 1.34, 0.16, 0.07, 0.03, and 0.02 mg kg^-1, respectively. Mean values of PM₁₀, PM_2.5, and Mn in all land-use settings were found 5.14, 1.34, and 1.9 times higher than the World Health Organization (WHO) guidelines. Mn was found as the most hazardous metal in terms of pollution load index (PLI) and contamination factor (CF) in the studied area. Health risk analysis for particle pollutants using air quality index (AQI) and geoinformation was found in the range between good to very critical for all the land-use settings. The hazard quotient (HQ) and hazard index (HI) were higher for children in comparison to adults, suggesting that children may be susceptible to potentially higher health risks. However, the cancer risk (CR) value for Pb ingestion (1.21 × 10^-6) in children was lower than the permissible limit (1 × 10^-4 to 1 × 10^-6). Nonetheless, for Cr inhalation, CR value (1.09 × 10^-8) was close to tolerable limits. Our findings can be of valuable assistance toward advancing our understanding of soil and air pollutions concerning public health in different land-use settings of the urbanized cities of Pakistan.

Spatial identification and temporal prediction of air pollution sources using conditional bivariate probability function and time series signature

Accurate identification of distant, large, and frequent sources of emission in cities is a complex procedure due to the presence of large-sized pollutants and the existence of many land use types. This study aims to simplify and optimize the visualization mechanism of long time-series of air pollution data, particularly for urban areas, which is naturally correlated in time and spatially complicated to analyze. Also, we elaborate different sources of pollution that were hitherto undetectable using ordinary plot models by leveraging recent advances in ensemble statistical approaches. The high performing conditional bivariate probability function (CBPF) and time-series signature were integrated within the R programming environment to facilitate the study's analysis. Hourly air pollution data for the period between 2007 to 2016 is collected using four air quality stations, (ca0016, ca0058, ca0054, and ca0025), situated in highly urbanized locations that are characterized by complex land use and high pollution emitting activities. A conditional bivariate probability function (CBPF) was used to analyze the data, utilizing pollutant concentration values such as Sulfur dioxide (SO2), Nitrogen oxides (NO2), Carbon monoxide (CO) and Particulate Matter (PM10) as a third variable plotted on the radial axis, with wind direction and wind speed variables. Generalized linear model (GLM) and sensitivity analysis are applied to verify and visualize the relationship between Air Pollution Index (API) of PM10 and other significant pollutants of GML outputs based on quantile values. To address potential future challenges, we forecast 3 months PM10 values using a Time Series Signature statistical algorithm with time functions and validated the outcome in the 4 stations. Analysis of results reveals that sources emitting PM10 have similar activities producing other pollutants (SO2, CO, and NO2). Therefore, these pollutants can be detected by cross selection between the pollution sources in the affected city. The directional results of CBPF plot indicate that ca0058 and ca0054 enable easier detection of pollutants' sources in comparison to ca0016 and ca0025 due to being located on the edge of industrial areas. This study's CBPF technique and time series signature analysis' outcomes are promising, successfully elaborating different sources of pollution that were hitherto undetectable using ordinary plot models and thus contribute to existing air quality assessment and enhancement mechanisms.

Chronic Low-Level Lead Exposure Increases Mesenteric Vascular Reactivity: Role of Cyclooxygenase-2-Derived Prostanoids

Lead (Pb) exposure causes hazardous effects as hypertension and other cardiovascular diseases. We evaluated whether chronic Pb exposure alters the peripheral vascular resistance measuring the vascular reactivity of mesenteric resistance arteries in rats to identify the underlying mechanisms that are associated to the development of Pb-induced hypertension. Mesenteric resistance arteries from lead-treated and untreated Wistar rats (1st dose: 10 μg/100 g; subsequent doses: 0.125 μg/100 g, intramuscular, 30 days) were used. Contractile responses to phenylephrine increased, while acetylcholine and sodium nitroprusside-induced relaxation was not affected by lead treatment. Endothelium removal and inhibition of NO synthase by L-NAME similarly enhanced the response to phenylephrine in untreated and lead-treated rats. The antioxidants apocynin and superoxide dismutase (SOD) did not affect vasoconstriction in either group. The vascular expression of cyclooxygenase-2 (COX-2) protein increased after lead exposure. The respective non-specific or specific COX-2 inhibitors indomethacin and NS398 reduced more strongly the response to phenylephrine in treated rats. Antagonists of EP1 (SC19220), TP (SQ29548), IP (CAY10441) and angiotensin II type 1 (losartan) receptors reduced vasoconstriction only in treated rats. These conclusions present further evidence that lead, even in small concentration, produces cardiovascular hazards being an environmental contaminant that account for lead-induced hypertension.

Drinking Water Quality Mapping Using Water Quality Index and Geospatial Analysis in Primary Schools of Pakistan

Primary school children in the developing world often lack potable water, which may result in a high burden of water-related diseases and poor school performance. The present study aimed to characterize the drinking water quality in primary schools of Pakistan. We used a multistage random-sampling method to select 425 primary schools from selected districts of Sindh province. Standard methods were used to characterize water quality. The results were compared with maximum acceptable values recommended by the Pakistani National Environmental Quality Standards (Pak NEQS) and the World Health Organization (WHO) drinking water quality standards. Groundwater (62%) and surface water (38%) were identified as two major drinking water sources in the selected schools with varying levels of water quality. Among all parameters, dissolved oxygen (DO), pH, and nitrate remained within WHO and Pak NEQS water quality standard limit, while total dissolved solids (TDS) (33%), electrical conductivity (EC) (46%), chloride (34%), turbidity (27%), and hardness (11%) samples exceeded standard limits. All dissolved salts had moderate to strong positive correlations with TDS and EC values. Based on a water quality index (WQI), 74% of primary schools had access to excellent or good quality drinking water compared to 26% of schools that had access to either poor, very poor or unsuitable drinking water. Among all three regions, more schools from South Sindh had either poor, very poor or unsuitable drinking water (33%) compared to the Central (25%) and North zones (15%). Hence, water from these locations is unfit for human consumption and these schools need better water quality management plans to stop the spread of water-related diseases in primary school children.

Clinical and Experimental Evidences of Hydrogen Sulfide Involvement in Lead-Induced Hypertension

Lead- (Pb-) induced hypertension has been shown in humans and experimental animals and cardiovascular effects of hydrogen sulfide (H₂S) have been reported previously. However, no studies examined involvement of H₂S in Pb-induced hypertension. We found increases in diastolic blood pressure and mean blood pressure in Pb-intoxicated humans followed by diminished H₂S plasmatic levels. In order to expand our findings, male Wistar rats were divided into four groups: Saline, Pb, NaHS, and Pb + NaHS. Pb-intoxicated animals received intraperitoneally (i.p.) 1st dose of 8 μg/100 g of Pb acetate and subsequent doses of 0.1 μg/100 g for seven days and sodium hydrosulfide- (NaHS-) treated animals received i.p. NaHS injections (50 μmol/kg/twice daily) for seven days. NaHS treatment blunted increases in systolic blood pressure, increased H₂S plasmatic levels, and diminished whole-blood lead levels. Treatment with NaHS in Pb-induced hypertension seems to induce a protective role in rat aorta which is dependent on endothelium and seems to promote non-NO-mediated relaxation. Pb-intoxication increased oxidative stress in rats, while treatment with NaHS blunted increases in plasmatic MDA levels and increased antioxidant status of plasma. Therefore, H₂S pathway may be involved in Pb-induced hypertension and treatment with NaHS exerts antihypertensive effect, promotes non-NO-mediated relaxation, and decreases oxidative stress in rats with Pb-induced hypertension.

DUOX expression in human keratinocytes and bronchial epithelial cells: Influence of vanadate

Dual oxygenases (DUOX) 1 and 2, expressed in many animal tissues, participate in host defense at mucosal surfaces and may have important signaling roles through generation of reactive oxygen. Present work addresses their expression in cultured human epidermal keratinocytes and effects of cytokines and metal/metalloid compounds. Both DUOX1 and 2 were expressed at much higher levels after confluence than in the preconfluent state. Maximal DUOX1 mRNA levels were 50 fold those of DUOX2. DUOX1 and 2 were induced ≈3 fold by interleukin 4, but only DUOX1 was induced by interferon gamma (IFNγ). In human bronchial HBE1 cells, by contrast, interleukin 4 induced only DUOX 1, and IFNγ induced only DUOX2. A survey in the keratinocytes of metal/metalloid compounds showed that arsenite, antimonite, chromate, cadmium, copper, lead and vanadate suppressed DUOX1 levels but did not prevent interleukin 4 stimulation. Effects on DUOX2 were less dramatic, except that vanadate potentiated the stimulation by IFNγ up to 7 fold. The results indicate that epithelial cell types of different tissue origins can differ in their cytokine regulation and that epidermal cells can exhibit striking alterations in response due to certain metal/metalloid exposures.

The features of morphological changes in the urinary bladder under combined effect of heavy metal salts

PURPOSE

This study is aimed to the investigation of the features of morphological changes in the urinary bladder of mature rats.

RESULTS

Received results shown that the experimental group of rats that had the intake of heavy metal salts (HMS) mixture during 30 and 90 days were observed histological and immunohistochemical changes in all structures of the urinary bladder. Depending on the period of influence of heavy metal ions on the wall of the organ, the pathological changes developed in cellular layers of the wall can lead to degenerative and later to atrophic and sclerotic changes.

CONCLUSIONS

This study demonstrates that high concentrations of HMS can significantly influence the body. The histological and immunohistochemical studies showed that the influence of the HMS combination leads to deep morphological changes in all structures of the urinary bladder. These changes depend on the period of intake of HMS. Analysis of the obtained results demonstrates the dependence of expression of morphological changes in the urinary bladder on the experiment duration. The final result of these changes may lead to the disorders of bladder's functions.