Abida Farooqi

Arsenic in groundwater and its health risk assessment in drinking water of Mailsi, Punjab, Pakistan

ABSTRACT The present study was aimed at assessing drinking water quality regarding arsenic (As) and its impact on health from Mailsi (Punjab), Pakistan. Forty-four groundwater samples were collected from two sites, Sargana and Mailsi. Arsenic and other cations were determined by atomic absorption spectrophotometer, whereas the anions were determined either through titration or spectrophotometer. The results revealed that dominant anions were HCO3− and Cl−, Ca+2 was the dominant cation, and overall water chemistry of the area was CaMgHCO3− type. Arsenic concentrations were high, ranging from 11 to 828 µg/L that crossed the World Health Organization permissible limits. Likewise, higher SO4−2 concentrations ranging from 247 to 1053 mg/L were observed. The health risk index was higher in the Sargana site, which employed the differences in terms of higher Average Daily Dose, Hazard Quotient, and Carcinogenic Risk of arsenic, which is unsuitable for drinking purposes. The area seems to be at high risk due to arsenic pollution and wells have never been tested for arsenic concentrations earlier; therefore, necessary measures should be taken to test the wells with respect to arsenic.

Legacy and emerging flame retardants (FRs) in the freshwater ecosystem: A review

In this review article, we have compiled and reviewed the previously published available literature on environmental distribution, behaviour, fate and regional trends of legacy and emerging flame retardants (FRs) including brominated (BFRs), organo-phosphate (OPFRs), novel brominated flame retardants (NBFRs) and dechlorane plus (DP) in the freshwater ecosystem. Transport and fate is discussed briefly with the evidences of de-bromination, sedimentation and accumulation in biota. De-bromination of BDE-209 is considered of concern because the lower brominated congeners are more toxic and mobile thus posing increased risk to the freshwater ecosystem. The available data on temporal and spatial trends as yet, is too few to show any consistent trends, enabling only general conclusions to be drawn. There is a lack of temporal studies in Asia, while, overall the trends are mixed, with both increasing and decreasing concentrations of BFRs and OPFRs. OPFRs and NBFRs have replaced classical BFRs (polybrominated diphenyl ethers (PBDEs)) in some countries but the amount of PBDEs in the environment is still considerable. Knowledge gaps and recommendations for future research are discussed emphasizing on further monitoring, advanced analytical methodologies, and risk assessment studies to completely understand the science of flame retardants in the freshwater ecosystem.

The evaluation of arsenic contamination potential, speciation and hydrogeochemical behaviour in aquifers of Punjab, Pakistan

In this study, we tested 123 groundwater wells from five different areas of Punjab, Pakistan for arsenic (As) contamination level and species, as well as delineated hydrogeochemical behaviour of As in aquifers. Results revealed that 75% and 41% of the groundwater wells exceeded the safe As limit of World Health Organisation (WHO, 10 μg L-1) and Pakistan-EPA (50 μg L-1), respectively. Arsenite (As(III)) and arsenate (As(V)) spanned 0-80% and 20-100% of total As (1.2-206 μg L-1), respectively. The mean As content (5.2 μg L-1) of shallow wells at 9-40 m depth did not exceed the WHO safe limit, representing a safe aquifer zone for pumping of groundwater compared to deeper wells at 41-90 m (51 μg L-1) and >90 m (23 μg L-1) depths. Piper-plot elucidated that the aqueous chemistry was dominated with Na-SO4, Na-Ca-SO4, Na-Mg-SO4 type saline water. Principal component analysis grouped As concentration with well depth, pH, salinity, Fe and CO3, exhibiting that these hydrogeochemical factors could have potential role in controlling As release/sequestration into the aquifers of study area. Geochemical modeling showed positive saturation indices only for iron (Fe) oxide-phases, indicating Fe oxides as the major carriers of As. Overall, this study provides insights to tackle emerging As threat to the communities in Punjab, Pakistan, as well as help develop suitable management/mitigation strategies - based on the baseline knowledge of As levels/species and factors governing As contamination in the study area.

Occurrence and methods to remove arsenic and fluoride contamination in water

Groundwater contamination with arsenic and fluoride has affected over 300 million people worldwide. Ingestion of arsenic and fluoride for extended period of time or at high concentration causes severe health effects. Arsenic can cause thickening and discoloration of the skin, cardiovascular disorders, cancer and skin lesions. Excessive intake of fluoride leads to dental and skeletal fluorosis and bone deformities. This report reviews the distribution of arsenic and fluoride contamination, their sources, mobilization and associated health risks. Remediation technologies to remove arsenic and fluoride are presented.

Health risk of arsenic in the alluvial aquifers of Lahore and Raiwind, Punjab Province, Pakistan: an investigation for safer well water

Environmental pollution has generated release of high amounts of arsenic (As) which ultimately are detected in the water of Indus Basin Punjab, Pakistan. The area is characterized by a semiarid climate, and alluvial deposits. This investigation, an extension of previously reported As-affected area in Lahore and Kasur, aimed to (1) assess the extent of water contamination in this area and (2) determine possible safer sites for future water use. In a comparative study, total As contamination of underground water from individual dwellings and community water supply of some villages located at the boundary of the Sheikhopura and Lahore districts, Pakistan were measured to compare with previously published data of villages located at the boundary of the Lahore and Kasur districts. The results showed variable levels of As in shallow drinking water wells and average concentration exceeding WHO guidelines value. As levels ranged from below 5.2 to 80 µg/L and mean 45.5 µg/L. The As concentrations were higher than WHO limits but lower than previous studied area. In addition, high salinity was found to be a serious concern for deteriorating groundwater quality rendering it unsuitable for drinking. Groundwater is predominantly of the Na–HCO3 type with slightly alkaline pH. High pH values and competition of As with HCO3 may serve as an important process for mobilization of As in the shallow groundwater of the region. Continuous monitoring and expansion of monitoring systems are necessary to establish safer wells within As-contaminated areas.

Arsenic and fluoride removal by potato peel and rice husk (PPRH) ash in aqueous environments

ABSTRACT Finding appropriate adsorbent may improve the quality of drinking water in those regions where arsenic (As) and fluoride (F−) are present in geological formations. In this study, we evaluated the efficiency of potato peel and rice husk ash (PPRH-ash)-derived adsorbent for the removal of As and F from contaminated water. Evaluation was done in batch adsorption experiments, and the effect of pH, initial adsorbate concentration, contact time, and adsorbent dose were studied. Characteristics of adsorbents were analyzed using scanning electron micropcope (SEM) and Fourier transform infrared (FTIR) spectroscopy. Both the Langmuir and Freundlich isotherm models fitted well for F− and As sorption process. The maximum adsorption capacity of adsorbent for As and F− was 2.17 μg g−1 and 2.91 mg g−1, respectively. The As and Fi removal was observed between pH 7 and 9. The sorption process was well explained with pseudo-second order kinetic model. Arsenic adsorption was not decreased in the presence of carbonate and sulfate. Results from this study demonstrated potential utility of this agricultural biowaste, which could be developed into a viable filtration technology for As and F− removal in As- and F-contaminated water streams.

Arsenic and fluoride co-contamination in shallow aquifers from agricultural suburbs and an industrial area of Punjab, Pakistan: Spatial trends, sources and human health implications

Release of arsenic (As) and fluoride (F−) species into groundwater is a serious health concern around the world. The present study was the first systematic baseline study conducted in Rahim Yar Khan district, Punjab, focusing on As and F− contamination in groundwater. A total of 51 representative groundwater samples comprising of 44 samples from agricultural suburbs and 7 from an industrial base were analysed. Statistical parameters, principal component analysis-multiple linear regression (PCA-MLR) and health risk assessment model were used to investigate the hydro geochemistry, spatial patterns, interrelation, source contribution and associated health risks of high As and F− in groundwater of the study area. Results showed high risk of F− exposure to people of the study area, with all samples exceeding the WHO standard of 1.5 mg/L, and for As, 32.5% of the studied groundwater samples exceeded the WHO standard (10 µg/L). The maximum As (107.23 µg/L) and F− (26.4 mg/L) levels were observed in samples close to the agricultural and smelting areas, implicating the frequent use of fertilizers and influence of industrial effluents in the study area. The PCA-MLR receptor model quantitatively illustrates that the majority of As and F− comes from natural sources, while, among anthropogenic sources, industrial and agricultural activities contributed the most. Health risk assessment revealed a high risk of As and F− contamination to the exposed population; therefore, detailed control strategies and policies are required in order to mitigate the health risks.

Fluoride prevalence in groundwater around a fluorite mining area in the flood plain of the River Swat, Pakistan

This study investigated the fluoride (F-) concentrations and physicochemical parameters of the groundwater in a fluorite mining area of the flood plain region of the River Swat, with particular emphasis on the fate and distribution of F- and the hydrogeochemistry. To better understand the groundwater hydrochemical profile and F- enrichment, groundwater samples (n=53) were collected from shallow (24-40m), mid-depth (48-65m) and deep (85-120m) aquifers, and then analysed using an ion-selective electrode. The lowest F- concentration (0.7mg/L) was recorded in the deep-aquifer groundwater, while the highest (6.4mg/L) was recorded in shallow groundwater. Most groundwater samples (62.2%) exceeded the guideline (1.5mg/L) set by the World Health Organization (WHO); while for individual sources, 73% of shallow-groundwater samples (F- concentration up to 6.4mg/L), 42% of mid-depth-groundwater samples, and 17% of deep-groundwater samples had F- concentrations that exceeded this permissible limit. Assessment of the overall quality of the groundwater revealed influences of the weathering of granite and gneisses rocks, along with silicate minerals and ion exchange processes. Hydrogeochemical analysis of the groundwater showed that Na+ is the dominant cation and HCO3- the major anion. The anionic and cationic concentrations across the entire study area increased in the following order: HCO3>SO4>Cl>NO3>F>PO4 and Na>Ca>Mg>K, respectively. Relatively higher F- toxicity levels were associated with the NaHCO3 water type, and the chemical facies were found to change from the CaHCO3 to (NaHCO3) type in calcium-poor aquifers. Thermodynamic considerations of saturation indices indicated that fluorite minerals play a vital role in the prevalence of fluorosis, while under-saturation revealed that - besides fluorite minerals - other F- minerals that are also present in the region further increase the F- concentrations in the groundwater. Finally, a health risk assessment via Deans classification method identified that the groundwater with relatively higher F- concentrations is unfit for drinking purposes.

Arsenic in Paddy Soils and Potential Health Risk

This chapter deals with the arsenic sources, its contamination in paddy soils, and its toxic effects to human health when it becomes the part of the food chain. Arsenic, the 20th abundant metalloid, exists naturally and has potential to become part of different matrices like air, soil, and water. In groundwater its contamination is recognized worldwide. Similarly, several studies indicate its contamination in paddy soils. Specially, arsenic has become a threat to sustainable rice cultivation in South and Southeast Asia. Rice has a special ability to uptake the arsenic, and it is a staple food in different countries of this region like Bangladesh, India, and Pakistan. In this region, people are at high risk of arsenic contamination through the ingestion of arsenic-contaminated rice. Thousands of people are suffering from the toxic effects of arsenic and its compounds all over the world. Arsenic in the human body is transported through the blood to the different organs of the body, in the form of MMA after ingestion. Its acute and chronic exposures cause several adverse health effects like dermal changes and respiratory, pulmonary, cardiovascular, gastrointestinal, hematological, hepatic, renal, neurological, developmental, reproductive, immunologic, genotoxic, mutagenetic, and carcinogenic effects. So, to overcome this issue, there is a need of modification in agricultural practices, genetic modifications, and public awareness regarding this menace.

Biodegradation of Xenobiotics in Soil by Fungi

Any substance foreign to a biological system is known as xenobiotic compound. The manufacturing and processing of xenobiotic chemicals on the large scale have led to serious surface and subsurface soil contamination. Biotransformation of the hazardous pollutants to less toxic substances or their complete mineralization represents an economical substitute to clean up soil and water. In principle, fungi by virtue of their enzymes can biodegrade any naturally existing biopolymers and some of the synthetic polymers as well. Degradation of polymers largely depends on the fungal extracellular enzymes, namely, oxidoreductases and hydrolases. White-rot ligninolytic fungal strains such as T. versicolor and P. ostreatus have been recognized to be the major decomposers of biopolymers via laccase-mediated transformation. Moreover, the ligninolytic fungal strains carrying enzyme Mn-peroxidase activity demonstrated the maximum degradation of naphthalene (69 %). Many non-ligninolytic species degrade polycyclic aromatic hydrocarbons (PAHs) via cytochrome P450 monooxygenase and epoxide hydrolase-catalyzed reactions to form transdihydrodiols. Remediation of nitro-aromatics along with their recalcitrant carcinogenic intermediates, possessing the worst degree of toxicity hazardous rating 3, has been described by utilizing fungal species such as Phanerochaete chrysosporium or Pseudomonas sp. ST53. Additionally, white-rot fungi possessing oxidative enzymes have the ability of TNT degradation and mineralization to CO2. On the other hand, fungal laccases have been reported to catalyze the transformation of the model endocrine disruptors, alkylphenols and biphenyls. For instance, T. versicolor catalyzed the partial transformation of nonylphenol into carbon dioxide. Discovering the new beneficial fungal strains in addition to isolation, engineering, and sequencing of new useful enzymes is highly desirable to further strengthen the biodegradation of contaminated soil.