Sana Khalid

COMSATS University Islamabad | CUI · Department of Environmental Science

Cobalt (Co) is a transition metal and is classified as a beneficial metal for plants, but its benefits for plants remain obscure. Cobalt has been reported to negatively affect plant physiochemical processes both at higher (toxic) and lower (deficient) applied levels. High concentrations of cobalt in plant organs cause irreversible changes to the pl...

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...

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 g...

• Soil processes affect metal chemical speciation and their biogeochemical activity.• The current study predicted chemical speciation of eight metals in two soil layers.• Divalent forms of metals predominated in both soil layers (79.9%).• Chromium showed a chemical speciation that varied from that of the other metals (95.8% as CrOH+).• Mean percent...

Arsenic (As) is an extremely toxic metalloid of global concern. Numerous health and environmental organizations have classified As being the “toxic and dangerous for the environment”. Environmental and food chain contamination by As has been described globally, especially in Asia. Numerous reports have reported high As contents in the groundwater o...

Wastewater (WW) produced from different activities can be a useful resource or an environmental issue depending on its use. If used properly, WW can be a good source of irrigation/nutrients for plants. Otherwise, it may endure environmental/plant health issues due to the presence of pollutants. Mixing of WW with freshwaters can dilute pollutant con...

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 fir...

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 ara...

Plant redox homeostasis governs the uptake, toxicity and tolerance mechanism of toxic trace elements and thereby elucidates the remediation potential of a plant. Moreover, plant toxicity/tolerance mechanisms control the trace element compartmentation in edible and non-edible plant organs as well as the associated health hazards. Therefore, it is im...

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 biophysicochemi...

Arsenic (As) and lead (Pb) are highly toxic and carcinogenic metal(loid)s. The present study evaluated the human exposure risk via estimating As and Pb uptake and physiological/biochemical modifications inside spinach plant grown under metal(loid)-contaminated growth medium. Plants were treated with three levels of each metal(loid) (0, 25 and 125 µ...

Nowadays, the use of wastewater for crop irrigation is increasing at global scale mainly due to freshwater scarcity and economic benefits. However, the presence of different types of pollutants including the trace elements (TEs) poses a serious threat to environmental and human health. This pot study evaluated the effect of alone and mixed irrigati...

Environmental contamination by toxic trace elements is a global issue faced by soil-plant-human systems. Biochar has gained substantial attention as a soil amendment to reduce toxic trace element impacts on plant and human health due to biochar’s capacity to influence trace element biogeochemistry. This review focuses on the key roles of biochar wi...

Despite considerable research of arsenic (As) level in ground/drinking water of Pakistan, scarce data is available regarding irrigation water contamination by As and associated health risks. The municipal wastewater is routinely applied for soil irrigation in peri-urban agriculture of the country. Since the wastewater composition/contamination and...

In peri-urban areas of district Vehari, farmers are using untreated city wastewater for crop irrigation owing to the scarcity of good-quality irrigation water. This practice may pose severe environmental and health issues to local inhabitants attributed to the high levels of potentially toxic metals in wastewater. The present study evaluated the po...

Depending on the use and management, wastewater generation can be a severe environmental dilemma or a potential source. Proper application and management of municipal water (MW) in agriculture could be its sustainable use. Until now, there is rare data about the combined application of wastewater and freshwater in agriculture that could be consider...

Arsenic (As) is a hazardous and potentially cancer-causing metal(loid). Nowadays, alarming concentrations of As have been observed in aquifers worldwide. This study investigated As contamination status of groundwater of district Vehari and explored the efficiency of various biosorbents (rice husk, corncobs, soybean hulls, cottonseed hulls and sugar...

In the present study, an indigenous biosorbent (leaves of Tecomella undulata) was used for the simultaneous removal of inorganic arsenic species (AsIII and AsV) from the stored rainwater in Tharparkar, Pakistan. The Plackett–Burman experimental design was used as a multivariate strategy for the evaluation of the effects of six factors/variables on...

The use of sewage water as an irrigation source can be beneficial in agricultural practices, however, it may result in human health risks due to the consumption of heavy metal(loid)–contaminated food. This study evaluated the suitability of using sewage water (SW), freshwater (FW), and groundwater (GW) for vegetable irrigation in District Vehari. S...

The presence of toxic substances in aquifers, particularly potentially toxic heavy metals, is an important environmental and social concern worldwide. These heavy metals are capable to exert many injurious health effects in human beings by intake of drinking metal-contaminated water. However, very little attention is paid towards quantitative and q...

Freshwater shortage and its contamination with various types of pollutants are becoming the most alarming issues worldwide due to impacts on socioeconomic values. Considering an increasing freshwater scarcity, it is imperative for the growers, particularly in semiarid and arid areas, to use wastewater for crop production. Wastewaters generally cont...

Copper (Cu) is an essential metal for human, animals and plants, although it is also potentially toxic above supra-optimal levels. In plants, Cu is an essential cofactor of numerous metalloproteins and is involved in several biochemical and physiological processes. However, excess of Cu induces oxidative stress inside plants via enhanced production...

Arsenic (As) is a highly toxic and carcinogenic element. It has received considerable consideration worldwide in recent years due to its highest toxicity to human, and currently, high concentrations observed in the groundwater. Some recent media and research reports also highlighted possible As contamination of groundwater systems in Pakistan. Howe...

Arsenic (As) is a well-known potentially toxic metalloid, which naturally occurs in soils, sediments, and aquatic environments. Arsenic has no essential role for living organisms. Its exposure to living organisms including humans causes severe health issues. Arsenic contamination of groundwater is a global issue especially in the flood plain region...

At the global scale, persistent lead (Pb) pollution has been considered as a major threat for human health due to its exposure through numerous pathways. The scientific literature regarding potential adverse health effects of Pb is mainly related with human exposure through ingestion, occupational exposure, or dermal absorption. Lead exposure mainl...

The biochemical/physiological variations in plant responses to heavy metals stress govern plant’s ability to phytoremediate/tolerate metals. So, the comparative effects of different types of heavy metals on various plant responses can better elucidate the mechanisms of metal toxicity and detoxification. This study compared the physiological modific...

Despite extensive research progress in the recent past, the data regarding foliar uptake of heavy metals, associated biophysiochemical changes inside plants and possible health hazards are limited. This study determined the effect of foliar application of lead oxide nanoparticles (PbO-NPs) on lead (Pb) accumulation, physiological and biochemical ch...

Atmospheric contamination by heavy metal enriched particulate matter (metal-PM) is highly topical nowadays because of its high persistence and toxic nature. Metal-PMs are emitted to the atmosphere by various natural and anthropogenic activities, later being the major source. After being released into the atmosphere, metal-PM can travel over a long...

Environmental contamination by a non-essential and non-beneficial, although potentially toxic mercury (Hg), is becoming a great threat to the living organisms at a global scale. Owing to its various uses in numerous industrial processes, high amount of Hg is released into different environmental compartments. Environmental Hg contamination can resu...

Pesticides are extensively used in the modern agricultural system. The inefficient and extensive use of pesticides during the last 5 to 6 decades inadvertently led to serious deterioration of environmental quality with health risk to living organisms including humans. It is important to use some environmentally-friendly and sustainable approaches t...

Heavy metal contamination of environment is becoming increasingly serious with rapid and unchecked industrialization and urbanization. Soil contamination with heavy metals and their associated health risks have been reported in various areas globally. Plants accumulate heavy metals from soil under contaminated environments. Inside plants, heavy met...

Currently, several news channels and research publications have highlighted the dilemma of arsenic (As) contaminated groundwater in Pakistan. However, there is lack of data regarding groundwater As content of various areas in Pakistan. The present study evaluated As contamination and associated health risks in previously unexplored groundwater of H...

This study is based on self-reported information collected from selected farmers of Vehari District, Punjab, Pakistan, to determine their technical knowledge and awareness about pesticide use and associated environmental and health risks. Moreover, soil contamination by routinely used persistent organochlorine pesticide, endosulfan, was also evalua...

Atmospheric contamination by heavy metal(loid)–enriched particulate matter (metal-PM) is highly topical these days because of its high persistence, toxic nature, and health risks. Globally, foliar uptake of metal(loid)s occurs for vegetables/crops grown in the vicinity of industrial or urban areas with a metal-PM-contaminated atmosphere. The curren...

The current study investigated the influence of organic amendments on cadmium (Cd) uptake and its effects on biochemical attributes of young and old leaves of bean. Bean seedlings were exposed to two levels of Cd (25 and 100 µM) in the presence and absence of different levels of ethylenediaminetetraacetic acid (EDTA) and citric acid (CA). An increa...

Environmental contamination by antimony (Sb), a non-essential and non-beneficial metalloid, is a great threat to living organisms at a global scale. Owing to its various uses in numerous industrial processes, Sb is released into different environmental compartments every year. Environmental Sb contamination can result in food chain bioaccumulation,...

In this study, column-scale laboratory experiments were performed to evaluate the arsenic (As) removal efficiency of different agricultural biowastes-derived biosorbents (orange peel, banana peel, rice husk) and biochar, using As-containing solutions and As-contaminated groundwater. All the biosorbents and biochar efficiently removed (50-100%) As f...

Atmospheric contamination by heavy metal-enriched particulate matter (metal-PM) is highly topical nowadays because of its high persistence and toxic nature. Metal-PMs are emitted to the atmosphere by various natural and anthropogenic activities, the latter being the major source. After being released into the atmosphere, metal-PM can travel over a...

Arsenic (As) contamination in different areas of the world has been reported, which poses serious health threats to humans by its different routes of exposure. There exists comparatively rare data regarding arsenic level in groundwater of Punjab, Pakistan, which is normally used for drinking purpose. Therefore, the present study was planned to asse...

Cadmium (Cd) phytoremediation potential and its accumulation in edible and non-edible plant tissues is the function of various biochemical processes taking place inside plants. This study assessed the impact of organic ligands on Cd phytouptake and different biophysiochemical processes of Spinacia oleracea L., and associated health hazards. Plants...

Arsenic contamination in water is a crucial human health and scientific challenge worldwide. Actually, high As levels above the recommended limit set by world health organization (10 µg/L) have been found in ground water of several countries around the world and millions of people have been exposed to As contaminated drinking water. The aim of the...

Globally, millions of people who rely on groundwater for potable purposes and agriculture have been inadvertently exposed to toxic arsenic (As) because of its natural occurrence in groundwater in several countries of Asia, Europe and America. While the presence of As in groundwater and its impacts on human health have been documented in many countr...

Purpose This study delineated the effect of calcium (Ca) and ethylenediaminetetraacetic acid (EDTA) addition on arsenic (As) accumulation and physiological attributes of Vicia faba L. Materials and methods Two separate experiments were performed. In the first experiment, V. faba seedlings, grown under hydroponic conditions, were exposed to three l...

Population densities and freshwater resources are not evenly distributed worldwide which have forced the farmers to use wastewater for irrigation of food crops. This practice presents both positive and negative effects with respect to its agricultural use, as well as in the context of environmental contamination and toxicology. Although wastewater...

Selenium (Se) is an essential trace element for humans and animals, although controversial for different plant species. There exists a narrow line between essential, beneficial and toxic levels of Se to living organisms which greatly varies with Se speciation, as well as the type of living organisms. Therefore, it is crucial to monitor its solid- a...

Most of the developing countries including Pakistan have poor sanitary conditions which cause numerous diseases in human. Therefore, the present work aimed at evaluating the physicochemical and microbial contamination of drinking water in urban areas of three tehsils (Vehari, Mailsi and Burewala) of district Vehari based on occurrence of water-born...

Despite significant recent advancement in research, biogeochemical behavior of heavy metals with respect to their applied form is still topical. Moreover, metal toxicity to plants may vary with their stage of development/maturity. Therefore, this study for the first time evaluated the influence of ethylenediaminetetraacetic acid (EDTA) and citric a...

Chromium (Cr) is a potentially toxic heavy metal which does not have any essential metabolic function in plants. Various past and recent studies highlight the biogeochemistry of Cr in the soil-plant system. This review traces a plausible link among Cr speciation, bioavailability, phytouptake, phytotoxicity and detoxification based on available data...

The current study examined the effect of calcium (Ca) and ethylenediaminetetraacetic acid (EDTA) on arsenic (As) uptake and toxicity to spinach (Spinacia oleracea) as well as assessed the potential human health risks. Spinach seedlings were exposed to three levels of As (25, 125, and 250 μM) alone or together with three levels of EDTA (25, 125, and...

Arsenic (As) is classified as a Class A human carcinogen and has gained a substantial attention in recent years owing to its high levels currently observed in the environment and adverse impacts on human health. Several studies have delineated the biogeochemical behaviour of As in soil-plant system in relation to its chemical speciation and bioavai...

The current study evaluated the effect of groundwater and wastewater irrigation on lead (Pb) accumulation in soil and vegetables, and its associated health implications. A pot experiment was conducted in which spinach (Spinacia oleracea), radish (Raphanus sativus) and cauliflower (Brassica oleracea) were irrigated with groundwater and wastewaters c...

In this study, we determined the effect of ethylenediaminetetraacetic acid (EDTA) and calcium (Ca) on arsenic (As) uptake and toxicity to Pisum sativum. Plants were treated with three levels of As (25, 125, 250 µM) in the presence and absence of three levels of Ca (1, 5, 10 mM) and EDTA (25, 125, 250 µM). Exposure to As caused an overproduction of...

Soil contamination with persistent and potentially (eco)toxic heavy metal(loid)s is ubiquitous around the globe. Concentration of these heavy metal(loid)s in soil has increased drastically over the last three decades, thus posing risk to the environment and human health. Some technologies have long been in use to remediate the hazardous heavy metal...

Anthropologic activities have transformed global biogeochemical cycling of heavy metals by emitting considerable quantities of these metals into the atmosphere from diverse sources. In spite of substantial and progressive developments in industrial processes and techniques to reduce environmental emissions, atmospheric contamination by toxic heavy...

Pesticides are widely used worldwide to control a range of pests infesting the agricultural crops. Increased use of pesticides has threaten human and enviroenmnetal health. In this book chapter, we have compiled data regarding pesticide use, soil and water contamination, and human poining in Pakistan. Pesticide utilization in Pakistan started in 19...

This review summarizes the findings of the most recent studies, published from 2000 to 2016, which focus on the biogeochemical behavior of Cd in soil-plant systems and its impact on the ecosystem. For animals and people not subjected to a Cd-contaminated environment, consumption of Cd contaminated food (vegetables, cereals, pulses and legumes) is t...

Heavy metal contamination of the environment through anthropogenic activities and/or natural processes is a widespread and serious problem. Heavy metals occur in various forms in soil, which differ greatly with respect to their solubility/bioavailability. The geochemical behavior of heavy metals in soil, their uptake by plants, and effect on crop p...