Arsenic level in groundwater and biological samples in Khanewal, Pakistan.

Groundwater is the most valuable natural source in our earth's planet, being contaminated in various regions worldwide. Despite considerable research, there are scarce data regarding arsenic (As) levels in groundwater and its build-up in biological samples in Pakistan. The current investigation analyzed As contamination in four tehsils of District Khanewal (Kabirwala tehsil, Jahaniyan tehsil, Mian Channu tehsil, and Khanewal tehsil). For that, 123 groundwater samples, 19 animal milk samples, 20 human nails, and 20 human hair samples were collected from the study area. Arsenic concentration in groundwater was up to 51.8 µg/L with an average value of 7.2 µg/L. About 28 water samples (23%) had As contents > WHO limit and 38 samples (31%) > DEP-NJ limit. Low levels of As were detected in biological samples. Average As levels were 23 µg/L in the milk samples and 298 µg/kg in human hair. Arsenic contents were not detected in nail samples, except in one sample from Kabirwala tehsil. The maximum values of hazard quotient and cancer risk in District Khanewal were 4.9 and 0.0022, respectively. It is anticipated that long-term use of As-containing water may led to poisoning of humans in the study area, especially in Kabirwala. Therefore, it is necessary to monitor As contamination in the groundwater of Kabirwala tehsil to reduce the potential health hazards.

Risk assessment of trace element accumulation in soil and Brassica oleracea after wastewater irrigation.

The risk assessment of trace elements has received substantial attention for the achievement of UN Sustainable Developmental Goals (UN-SDGs). The present study aimed to evaluate health and ecological risks associated with trace element accumulation in Brassica oleracea under wastewater irrigations from three different areas. This study, for the first time, compared the pros and cons of mixed water crop irrigation (wastewater with fresh/groundwater). A pot experiment was conducted to evaluate the buildup of eight trace elements (As, Cu, Cd, Mn, Fe, Pb, Ni and Zn) in soil and B. oleracea plants irrigated with wastewater alone and mixed with fresh/groundwater. Specific ecological [degree of contamination (Cd), potential ecological risk index (PERI), pollution load index (PLI), geo-accumulation index (Igeo)], phytoaccumulation [bioconcentration factor (BCF) and transfer factor (TF)] and health risk models [chronic daily intake (CDI), hazard quotient (HQ), cancer risk (CR)] were applied to assess the overall contamination of trace elements in the soil-plant-human system. Moreover, these indices were compared with the literature data. The concentration of Cd, Fe and Mn exceeded the threshold limits of 10, 500 and 200 mg kg-1, respectively, for agricultural soil. Overall, all the irrigation waters caused significant pollution load in soil indicating high ecological risk (Cd > 24, PERI > 380, Igeo > 5, PLI > 2). Not all the mixing treatments caused a reduction in trace element buildup in soil. The mixing of wastewater-1 with either groundwater or freshwater increased trace element levels in the soil as well as risk indices compared to wastewater alone. The BCF and TF values were > 1, respectively, for 66% and 7% treatments. Trace element concentration in plants and associated health risk were minimized in mixed wastewater treatments. There were 22% and 32% reduction in HQ and CR when wastewater was mixed with freshwater and 29% and 8% when mixed with groundwater. Despite total reduction, a great variation in % change in risk indices was observed with respect to the area of wastewater collection. Therefore, mixed water irrigation may be a good management strategy, but its recommendation depends on soil properties and composition of waters used for mixing. Moreover, it is recommended that the freshwater and wastewater of the particular area may be continuously monitored to avoid potential associated health hazards.

Biowaste-based sorbents for arsenic removal from aqueous medium and risk assessment.

Water contamination by arsenic (As) is widespread and is posing serious health threats globally. Hence, As removal techniques/adsorbents need to be explored to minimize potentials hazards of drinking As-contaminated waters. A column scale sorption experiment was performed to assess the potential of three biosorbents (tea waste, wheat straw and peanut shells) to remove As (50, 100, 200 and 400 µg L-1) from aqueous medium at a pH range of 5-8. The efficiency of agricultural biosorbents to remove As varies greatly regarding their type, initial As concentration in water and solution pH. It was observed that all of the biosorbents efficiently removed As from water samples. The maximum As removal (up to 92%) was observed for 400 µg L-1 initial As concentration. Noticeably, at high initial As concentrations (200 and 400 µg L-1), low pH (5 and 6) facilitates As removal. Among the three biosorbents, tea waste biosorbent showed substantial ability to minimize health risks by removing As (up to 92%) compared to peanut shells (89%) and wheat straw (88%). Likewise, the values of evaluated risk parameters (carcinogenic and non-carcinogenic risk) were significantly decreased (7-92%: average 66%) after biosorption experiment. The scanning electron microscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray and X-ray diffraction analyses confirmed the potential of biosorbents to remediate As via successful loading of As on their surfaces. Hence, it can be concluded that synthesized biosorbents exhibit efficient and ecofriendly potential for As removal from contaminated water to minimize human health risk.

Chromium removal from aqueous solution using bimetallic Bi0/Cu0-based nanocomposite biochar.

Chromium (Cr), due to its greater contamination in aquifers and distinct eco-toxic impacts, is of greater environmental concern. This study aimed to synthesize nanocomposites of almond shells biochar (BC) with zerovalent bismuth and/or copper (Bi0/BC, Cu0/BC, and Bi0-Cu0/BC) for the removal of Cr from aqueous solution. The synthesized nanocomposites were investigated using various characterization techniques such as XRD, FTIR spectroscopy, SEM, and EDX. The Cr removal potential by the nanocomposites was explored under different Cr concentrations (25-100 mg/L), adsorbent doses (0.5-2.0 g/L), solution pH (2-8), and contact time (10-160 min). The above-mentioned advanced techniques verified successful formation of Bi0/Cu0 and their composite with BC. The synthesized nanocomposites were highly effective in the removal of Cr. The Bi0-Cu0/BC nano-biocomposites showed higher Cr removal efficiency (92%) compared to Cu0/BC (85%), Bi0/BC (76%), and BC (67%). The prepared nanocomposites led to effective Cr removal at lower Cr concentrations (25 mg/L) and acidic pH (4.0). The Cr solubility changes with pH, resulting in different degrees of Cr removal by Bi0-Cu0/BC, with Cr(VI) being more soluble and easier to adsorb at low pH levels and Cr(III) being less soluble and more difficult to adsorb at high pH levels. The experimental Cr adsorption well fitted with the Freundlich adsorption isotherm model (R2 > 0.99) and pseudo-second-order kinetic model. Among the prepared nanocomposites, the Bi0-Cu0/BC showed greater stability and reusability. It was established that the as-synthesized Bi0-Cu0/BC nano-biocomposite showed excellent adsorption potential for practical Cr removal from contaminated water.

Comparison of As removal efficiency and health risks from aqueous solution using as-synthesized Fe0 and Cu0: modelling, kinetics and reusability.

Batch scale removal of arsenic (As) from aqueous media was explored using nano-zero valent iron (Fe0) and copper (Cu0) particles. The synthesized particles were characterized using a Brunauer-Emmett-Teller (BET) surface area analyzer, a scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). The BET result showed that the surface area (31.5 m2/g) and pore volume (0.0415 cm3/g) of synthesized Fe0 were higher than the surface area (17.56 m2/g) and pore volume (0.0287 cm3/g) of Cu0. The SEM results showed that the morphology of the Fe0 and Cu0 was flowery microspheres and highly agglomerated with thin flakes. The FTIR spectra for Fe0 showed broad and intense peaks as compared to Cu0. The effects of the adsorbent dose (1-4 g/L), initial concentration of As (2 mg/L to 10 mg/L) and solution pH (2-12) were evaluated on the removal of As. Results revealed that effective removal of As was obtained at pH 4 with Fe0 (94.95%) and Cu0 (74.86%). When the dosage increased from 1 to 4 g L-1, the As removal increased from 70.59 to 93.02% with Fe0 and from 67 to 70.59% with Cu0. However, increasing the initial As concentration decreased the As removal significantly. Health risk indices, including estimated daily intake (EDI), hazard quotient (HQ), and cancer risk (CR) were employed and a significant decline (up to 99%) in risk indices was observed in As-treated water using Fe0/Cu0. Among the adsorption isotherm models, the values of R2 showed that isothermal As adsorption by Fe0 and Cu0 was well explained by the Freundlich adsorption isotherm model (R2 > 0.98) while the kinetic experimental data was well-fitted with the Pseudo second order model. The Fe0 showed excellent stability and reusability over five sorption cycles, and it was concluded that, compared to the Cu0, the Fe0 could be a promising technology for remediating As-contaminated groundwater.

Effect of freshwater and wastewater irrigation on buildup of toxic elements in soil and maize crop.

Untreated wastewater is routinely used for agricultural activities in water-stressed regions, thereby causing severe ecological risks by various pollutants. Hence, management strategies are needed to cope with the environmental issues related to wastewater use in agriculture. This pot study evaluates the effect of mixing either freshwater (FW) or groundwater (GW) with sewage water (SW) on the buildup of potentially toxic elements (PTEs) in soil and maize crop. Results revealed that SW of Vehari contains high levels of Cd (0.08 mg L-1) and Cr (2.3 mg L-1). Mixing of FW and GW with SW increased soil contents of As (22%) and decreased Cd (1%), Cu (1%), Fe (3%), Mn (9%), Ni (9%), Pb (10%), and Zn (4%) than SW "alone" treatment. Risk indices showed high-degree of soil-contamination and very-high ecological risks. Maize accumulated considerable concentrations of PTEs in roots and shoot with bioconcentration factor > 1 for Cd, Cu, and Pb and transfer factor > 1 for As, Fe, Mn, and Ni. Overall, mixed treatments increased plant contents of As (118%), Cu (7%), Mn (8%), Ni (55%), and Zn (1%), while decreased those of Cd (7%), Fe (5%), and Pb (1%) compared to SW "alone" treatments. Risk indices predicted possible carcinogenic risks to cow (CR 0.003 > 0.0001) and sheep (CR 0.0121 > 0.0001) due to consumption of maize fodder containing PTEs. Hence, to minimize possible environmental/health hazards, mixing of FW and GW with SW can be an effective strategy. However, the recommendation greatly depends on the composition of mixing waters.

Relationship Between Mass Loss and Fruit Quality of Sweet Orange at Two Different Storage Conditions.

Mass loss from fresh produce is linked to a reduction of its aesthetic value. However, a relationship between mass loss and biochemical quality parameters at different storage conditions has not been widely explored. Therefore, the current study is designed with the objectives to determine the behavior of fruit quality parameters and a relationship between fruit mass loss and fruit quality at two different storage conditions. Sweet orange fruit stored in a zero energy cool chamber (ZECC) had greater shelf-life of more than 15 days, fruit size (62.40 mm) and peel (35.15%) and lower mass loss (4.94%), juice (32.19%) and electrical conductivity (EC) (2.06 S/m) as compared to ambient conditions in laboratory during 25 days of storage. In ZECC, only EC was positively correlated (r = 0.57) with mass loss, whereas at room temperature EC (r = 0.76), total soluble solids (TSS) (r = 0.60) and fruit internal temperature (r = 0.64) were positively and peel (%) (r = -0.52) and fruit diameter (r = -0.49) were negatively correlated with mass loss. Correlation of combined storage conditions revealed that EC (r = 0.47) and TSS (r = 0.50) were positively and peel (%) (r = -0.77) and fruit diameter (r = -0.55) were negatively correlated with mass loss (%). The principal component analysis (PCA) revealed that the scores of room temperature were strongly associated with TSS, pH, EC, mass loss (%), juice (%) and internal temperature (°C), whereas scores of ZECC were strongly associated with pulp (%), ascorbic acid (mg 100 mL-1), acidity (%), and fruit diameter (mm).

Accumulation pattern and risk assessment of potentially toxic elements in selected wastewater-irrigated soils and plants in Vehari, Pakistan.

There are scarce data about the accumulation pattern and risk assessment of potentially toxic elements (PTEs) in soil and associated potential ecological risks, especially in less-developed countries. This study aims to assess the pollution levels and potential ecological risks of PTEs (As, Cr, Cd, Cu, Ni, Mn, Pb and Zn) in wastewater-irrigated arable soils and different edible-grown plants in selected areas of Vehari, Pakistan. The results revealed that the values of PTEs in soil samples were higher than their respective limit values by 20% for As, 87% for Cd, 15% for Cu, 2% for Cr, 83% for Mn, 98% for Fe, and 7% for Zn. The values of soil risk indices such as the potential ecological risk (PERI >380 for all samples), pollution load index (PLI >4 for 94% of studied samples), and degree of contamination (Dc > 24 for all samples) showed severe soil contamination in the study area. Some vegetables exhibited a high metal accumulation index (e.g., 8.1 for onion), signifying potential associated health hazards. Thus, long-term wastewater irrigation has led to severe soil contamination, which can pose potential ecological risks via PTE accumulation in crops, particularly Cd. Therefore, to ensure food safety, frequent wastewater irrigation practices need to be minimized and managed in the study area.

Multivariate analysis of accumulation and critical risk analysis of potentially hazardous elements in forage crops.

Potentially hazardous element (PHE) contamination of aquifers is an issue of global concern, as this not only affects soil and plants but also exerts a negative impact on livestock. The current study assessed the extent of PHE (cadmium, copper, nickel, and lead) contamination of groundwater, soil, and forage crops in Shorkot, Punjab, Pakistan. Low concentrations of PHEs, particularly Cd and Cu, were found in drinking water which remained below detection limits. The concentrations of Ni and Pb in water samples were 0.1 and 0.06 mg L-1, respectively. Calculated risk indices showed that there was a high carcinogenic and non-carcinogenic risk to livestock (sheep and cow/buffalo) from the ingestion of Ni- and Pb-contaminated water. Soil irrigation with contaminated water resulted in PHE accumulation (Cd: 0.4 mg kg-1, Cu: 16.8 mg kg-1, Ni: 17.6 mg kg-1, Pb: 7.7 mg kg-1) in soil and transfer to forage crops. The potential impact of PHE contamination of the groundwater on fodder plants was estimated for animal health by calculating the average daily dose (ADD), the hazard quotient (HQ), and the cancer risk (CR). While none of the PHEs in forage plants showed any carcinogenic or non-carcinogenic risk to livestock, a high exposure risk occurred from contaminated water (HQ: 12.9, CR: 0.02). This study provides baseline data for future research on the risks of PHE accumulation in livestock and their food products. Moreover, future research is warranted to fully understand the transfer of PHEs from livestock products to humans.

Distribution and health risk assessment of trace elements in ground/surface water of Kot Addu, Punjab, Pakistan: a multivariate analysis.

Water is a key component for living beings to sustain life and for socio-economic development. Anthropogenic activities contribute significantly to ground/surface water contamination particularly with trace elements. The present study was designed to evaluate distribution and health risk assessment of trace elements in ground/surface water of the previously unexplored area, Tehsil Kot Addu, Southern-Punjab, Pakistan. Ground/surface water samples (n = 120) were collected from rural and urban areas of Kot Addu. The samples were analyzed for physicochemical characteristics: total dissolved solids (TDS), pH, and EC (electrical conductivity), cations, anions, and trace elements particularly arsenic (As), lead (Pb), cadmium (Cd), and zinc (Zn). All of the water characteristics were evaluated based on the water quality standards set by World Health Organization (WHO). Results revealed the suitability of water for drinking purpose with respect to physicochemical attributes. However, the alarming levels of trace elements especially As, Cd, and Pb make it unfit for drinking purpose. Noticeably, 23, 96, and 98% of water samples showed As, Cd, and Pb concentrations higher than the permissible limits. Overall, the estimated carcinogenic and non-carcinogenic risk to the exposed community was higher than the safety level of USEPA, suggesting the probability of cancer and other diseases through long-term exposure via ingestion routes. Therefore, this study demonstrated an urgent need for water filtration/purification techniques, and some quality control measures are warranted to protect the health of the exposed community in Tehsil Kot Addu.

Zinc in soil-plant-human system: A data-analysis review.

Zinc (Zn) plays an important role in the physiology and biochemistry of plants due to its established essentiality and toxicity for living beings at certain Zn concentration i.e., deficient or toxic over the optimum range. Being a vital cofactor of important enzymes, Zn participates in plant metabolic processes therefore, alters the biophysicochemical processes mediated by Zn-related enzymes/proteins. Excess Zn can provoke oxidative damage by enhancing the levels of reactive radicals. Hence, it is imperative to monitor Zn levels and associated biophysicochemical roles, essential or toxic, in the soil-plant interactions. This data-analysis review has critically summarized the recent literature of (i) Zn mobility/phytoavailability in soil (ii) molecular understanding of Zn phytouptake, (iii) uptake and distribution in the plants, (iv) essential roles in plants, (v) phyto-deficiency and phytotoxicity, (vi) detoxification processes to scavenge Zn phytotoxicity inside plants, and (vii) associated health hazards. The review especially compares the essential, deficient and toxic roles of Zn in biophysicochemical and detoxification processes inside the plants. To conclude, this review recommends some Zn-related research perspectives. Overall, this review reveals a thorough representation of Zn bio-geo-physicochemical interactions in soil-plant system using recent data.