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The increasing concentration of potentially toxic elements (PTEs) in agricultural soils has greatly disturbed the quality and productivity of soils. In this study, we investigated the uptake and distribution of cadmium (Cd), lead (Pb), and nickel (Ni) by two Brassica cultivars (Khanpur raya and Sandal canola) grown on soil irrigated with metal-contaminated water. Distilled water was spiked with salts to prepare irrigation water with various levels of metals (Ni application at 90, Cd at 20, Pb at 500, Ni + Pb at 20 + 500, Ni + Cd at 90 + 20, Cd + Pb at 20 + 500, and Ni + Cd + Pb at 90 + 20 + 500 mg L−1). These treatments were compared with water without the addition of any salt. The results indicated that compared to the control treatment, increasing metal concentrations decreased the shoot weight (44.25%, 29.03%), root length (33.33%, 12.74%), and shoot length (19.73%, 11.06%) in Khanpur raya and Sandal canola, respectively. Compared to the control treatment, irrigation with contaminated water decreased the photosynthesis rate (98.42%, 99.34%), chlorophyll content (18.27%, 13.73%), respiration rate (7.97%, 6.47%), and transpiration rate (9.90%, 33.33%) in both varieties, respectively. Notably, the concentrations of Ni (0.01 and 0.003), Cd (0.01 and 0.012), and Pb (0.03 and 0.05%) in the seeds were increased, as well as in Khanpur raya and Sandal canola, respectively, compared to the controls. Furthermore, the PTE accumulation in different components was recorded, with the order of soil > root > shoot > seed. It was observed that brassica cultivars differed significantly in their response to the growth and accumulation of PTEs in edible parts. It was concluded that Khanpur raya did not exhibit a decline in growth due to PTEs in irrigation water and prevented the translocation of PTEs towards edible parts compared to Sandal canola and thus can be safely grown in soils receiving PTE-contaminated water. [ABSTRACT FROM AUTHOR]

Screening various plant species to act as hyperaccumulators and associated health risks could serve as a sustainable solution for the bioremediation heavy metals (HMs). For the first time, the present study explored the phytoremediation potential of native plants, soil enrichment, and human health risks associated with the contamination of HMs in soil and plant samples collected from a municipal solid-waste open dump site. Soil and plant samples (n = 18 + 18) from the dumpsite and (n = 18) from the control site were analyzed for selected HMs, i.e., Chromium (Cr), Lead (Pb), Nickel (Ni), Iron (Fe), and Zinc (Zn). The phytoremediation potential of plants was assessed using the bioaccumulation factor (BAF), bioaccumulation coefficient (BAC), and translocation factor (TF), while soil pollution levels were evaluated using the contamination factor (CF), geoaccumulation index (Igeo), enrichment factor (EF), potential ecological risk index (PERI), and human health risk indices. The results revealed that based on TF and BAC values, Alhagi maurorum Medic., Astragalus creticus Lam., Cichorium intybus L., Berberis lycium Royle, and Datura stramonium L. were hyperaccumulators for Cr while Parthenium hysterophorus L. was a promising species for both Ni and Cr. Similarly, CF values for Fe, Ni, Pb, and Cr were >6, thereby showing very high contamination, while Igeo values for Fe, Ni, Pb, and Cr were (class 6, >5), showing that the soil was extremely polluted. Furthermore, EF values for Fe, Ni, Pb, Cr, and Zn were 2 < EF ≤ 5, depicting moderate enrichment, while PERI values were in the range of 91.31–195.84, employing moderate ecological risks (95 < PERI < 190) from the dumpsite's soil. Moreover, for non-carcinogenic exposure, none of the analyzed metals exceeded the threshold limit HRI values > 1 in both adults and children. Likewise, in the case of carcinogenic effects, the CRI values were lower than the tolerable limits (1 × 10−6–1 × 10−4) in both adults and children. Moreover, almost all studied plants could be utilized for the phytoextraction of mentioned HMs. In future, the present study can help in the implementation of public policies to ensure sustainability and developmental activities in contaminated sites. Based on these results, it is concluded that there is a dire need of monitoring solid waste dumpsites due to various types of potential risks associated with the contamination of HMs. Moreover, to minimize the potential health problems arising from the dumpsite, it is substantive that special attention should be paid to work on sustainable and eco-friendly remedial measures. [ABSTRACT FROM AUTHOR]

Natural springs which originate from hilly areas of Skardu in Pakistan make their route downward and are utilized by the public as they passes from residential areas. Due to weathering processes in mountainous regions, these springs can be the source of various trace elements and pollutants. Keeping in mind the same concept, ten mostly used freshwater springs were selected to evaluate their drinking water quality in the Skardu region. Three samples of water from each spring (start/mouth, 100 m away from the mouth, and 200 m away from mouth) were collected and analyzed for water quality via Water Quality Index (WQI). The main parameters of spring water were recorded in the laboratory as electrical conductivity (EC), total dissolved solids (TDS), residual sodium carbonate (RSC), and sodium adsorption ratio (SAR), and secondary parameters, i.e., Kelley's ratio (KR), permeability index (PI), and WQI, were derived. Besides these parameters, heavy metal pollutants (Cd, Cr, Mn, and Cu) were also determined from the water samples. The results showed that the assessed parameters TDS, SSP, KR, and PI were found within the safer limits of drinking water as prescribed by the Pak-EPA and WHO. However, among trace elements, only Cd (0.03 mg L−1) was found above the permissible limits of 0.01 mg L−1 as given by the GOP-EPA (2008) and WHO (1996) at Shigri Bala spring 200 m away. Similarly, at 2 ft from the mouth of Chumig S1 spring, its concentrations were recorded 0.03 mg L−1, and at Benazir Chowk spring (100 m away), it was found 0.02 mg L−1. In general, the Water WQI demonstrates that springs have good water quality. Our findings are useful for the environmental protection managers and citizens of the Skardu concerned with the water quality of the springs. [ABSTRACT FROM AUTHOR]

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 acid (CA) on cadmium (Cd) accumulation and toxicity to germinating and young pea seedlings as well as in younger and older leaves. The experimental setup of current study consisted of two separate studies. The first study was performed on germinating seedlings grown in a Cd-contaminated sand media. Pea seeds were treated with two levels of Cd (Cd-25 and Cd-100) alone and combined with different levels of EDTA and CA. The second study was carried out in hydroponic solution. The influence of organic amendments on Cd accumulation and toxicity to pea plants was evaluated by determining Cd contents in pea seedlings, H 2 O 2 contents, chlorophyll contents and lipid peroxidation in younger and older leaves. Cadmium stress caused overproduction of H 2 O 2 in roots and leaves of pea seedlings. Cadmium-induced overproduction of H 2 O 2 caused a decrease in the pigment contents and increased lipid peroxidation. Application of EDTA at higher levels (81 and 200 µM) increased Cd accumulation by pea plants. However, CA did not affect Cd accumulation by pea. Both EDTA and CA increased Cd-induced H 2 O 2 production and lipid peroxidation. Younger pea leaves showed more sensitivity to Cd stress compared to older leaves. Similarly, Cd toxicity was more pronounced in germinating seedlings than young seedlings. Moreover, Pearson correlation and principal component analysis (PCA) showed very interesting correlations between treatments and stress responses of germination and young seedlings as well as younger and older leaves. Based on multivariate analysis, it is proposed that the Cd toxicity to pea plants greatly vary with its growth stage and the maturity of organs (younger or older leaves). [ABSTRACT FROM AUTHOR]

Contamination of agricultural soils with lead (Pb) is a widespread problem which is mainly due to anthropogenic activities. The present study investigated the effect of organic and inorganic amendments on wheat growth and reducing Pb concentration in the plant. A greenhouse experiment was conducted on Pb spiked soil (500 mg kg of soil) with the application of farmyard manure, poultry manure, gypsum and di-ammonium phosphate (DAP). Plants were harvested after 120 days of growth and analyzed for Pb concentration in different plant parts. Under Pb stress, amendments significantly ( p < 0.05) increased grain yield and root dry weights compared to the control. Grain yield and dry weights of shoots and roots were maximum with DAP compared to the control and other amendments. Amendments increased transpiration rate, stomatal conductance, chlorophyll contents and photosynthetic rate. The lowest Pb concentration was found in DAP treated plants which were about 88%, 84%, and 85% lower in root, shoots and grains than control respectively. DAP fertilizer was the most effective in improving these parameters than control and other amendments and can be used to reduce Pb concentration in wheat and probably other crops. [ABSTRACT FROM AUTHOR]

Naturally occurring phosphate rock is the only essential source for the production of fertilizers. Heavy metals and phosphate concentrations are quite higher in phosphate rock formed by sedimentary processes. This detail study was conducted to evaluate the heavy metal concentrations in part of the Hazara region, which is the only source of phosphate fertilizer in the country. Heavy metals are considered as one of the main pollutant responsible for environmental contamination of soil. This study included the concentration of phosphorite in the Hazara region in the three useful forms: total phosphorite, extractable phosphorite and water soluble forms. The phosphorous extracted from sedimentary deposits used to maintain the natural content in agricultural soil which was being depleted due to the regular practice of crop harvest. The data collected during this studies were statically analyzed which refers the significant variations in P, Zn, Cr, Mn, As, Cu, Fe, Ni, & Pb. Zn and Cr concentration in Hazara phosphates. Heavy metals for instance Pb, Cr, Zn and Cu present in higher amount than usable limits and may create environmental pollution (air, surface & groundwater and soil) and health issues of humans. Therefore it is recommended that managing remedial steps are necessary around the mining regions to avoid environmental and health issues. [ABSTRACT FROM AUTHOR]

Urbanization and industrialization have resulted in contamination of soils with heavy metals and other pollutants. Nickel (Ni) is one of the toxic metals, which adversely affect plant growth by altering different physiological and metabolic processes. Mineral nutrients can reduce toxic effects of Ni on physiological and metabolic functions of plants, thus improving plant growth. The role of calcium (Ca) to alleviate Ni toxicity in rice was investigated. Rice plants were grown with Ni (20 and 40 mg kg−1) and Ca (80 and 160 mg kg−1) in different combinations and without Ni and Ca as a control. Nickel (40 mg kg−1) significantly decreased shoot (54%) and root dry weights (54%), chlorophyll content (57%), the photosynthetic rate (two-fold), transpiration rate (34%) and stomatal conductance (39%) compared to control. Application of Ni (40 mg kg−1) increased the Ni concentration in shoots 22-fold and in roots 11-fold compared to control. Application of Ca (160 mg kg−1) reduced the adverse effects of Ni and the studied parameters improved to the maximum values compared to control. Calcium decreased the translocation of Ni towards the shoots that was evident from a lower translocation factor (42%) for the plants supplied with Ca compared to those grown without Ca (62%). The phytotoxicity induced by Ni on different growth and physiological parameters was alleviated by Ca as indicated by the minimum values of the phytotoxicity index for Ca fed plants (0) compared to those without Ca (2.6). [ABSTRACT FROM AUTHOR]

Nickel (Ni) contamination in soil is a widespread problem in this era of industrial development. Plant cultivars respond differentially to Ni contamination in soil. In the present study, we have investigated the effect of different Ni levels to the growth and mineral status of two wheat cultivars (Sehar-2006 and LU-26). Five different levels of Ni as NiSO4 · 4 H2O (0, 30, 45, 60, and 75 mg kg−1) were applied to soil in the pots. LU-26 performed better compared to Sehar-2006 in terms of dry weight production and physiological parameters. LU-26 contained higher Ni in roots compared to Sehar-2006, but the Ni concentration in shoots of both the cultivars was similar. LU-26 translocated less Ni toward the shoot compared to Sehar-2006 indicating the exclusion of Ni from shoots and retaining it in roots by LU-26 as evident from bioconcentration and translocation factors. Contradictly, Sehar-2006 translocated more Ni from root to shoot indicating its tolerance to Ni. Ni increased manganese (Mn) in shoots of Sehar-2006 and LU-26 up to 60 and 30 mg kg−1, respectively. Ni decreased copper (Cu) and zinc (Zn) concentration in shoots of both cultivars, however Zn concentration in roots increased at all levels of Ni. LU-26 excluded Ni from shoots and Sehar-2006 accumulated Ni in shoots. The present study helps in understanding the process of metal uptake and distribution during the early growth stages of the plant and can signify overall potential of a crop for its exploitation on contaminated soils. [ABSTRACT FROM AUTHOR]

Metal contamination of the soils is a widespread problem and immobilization of metals with organic amendments is one of the different remediation technologies. We investigated the effect of activated carbon, poultry manure and pressmud on immobilization of nickel, manganese, copper, zinc, iron and lead in the contaminated soil, plant growth and metal concentrations in maize shoots. The amendments were applied to the soil at the rate of 4% on dry weight basis. Amendments significantly (P < 0.001) affected shoot dry weight and concentrations of all metals in maize shoots as compared to the control. The maximum shoot dry weight (4.54 g pot-1) was recorded with pressmud, while it was minimum with the control (2.22 g pot-1). Maize shoots contained the minimum nickel (3.54 mg kg-1) with activated carbon and the minimum concentrations of manganese (11.02 mg kg-1), zinc (48.06 mg kg-1) and iron (104.66 mg kg-1) were recorded with pressmud. Maize shoots contained the minimum concentrations of copper (25.41 mg kg-1) and lead (53.40 mg kg-1) with poultry manure and control, respectively. Amendments significantly (P < 0.001) decreased ammonium bicarbonate-diethylene triamine penta acetic acid (AB-DTPA) extractable concentrations of metals except lead. Activated carbon treated pots had minimum AB-DTPA extractable concentrations of all the metals except iron and lead. Activated carbon was most effective in immobilization of Ni, Mn, Zn and Cu decreasing AB-DTPA extractable Ni in the soil, while Fe and Pb was increased due to application of other amendments. [ABSTRACT FROM AUTHOR]

Assessment of trace elements is inevitable to reduce stress on environment due to urbanization and industrialization. Rawalpindi, the fourth largest city of Pakistan, rapidly moving towards industrialization and has a large number of automobiles. In the present study, the urban area of Rawalpindi was divided into five parts: Gawal Mandi, Pir Wadhai, Soan Adda, Chah Sultan, and Central Ordinance Depot (COD), to determine distribution of trace elements. Soil samples were collected from 5 to 20 cm depth. After drying and sieving, samples were digested using di-acid (HNO3 and HClO4 at 2:1). Concentrations of heavy metals were determined using atomic absorption spectrophotometer (AAS). Principal component analysis (PCA) was performed to reduce multidimensional space of variables and samples. Observed mean concentrations of Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn were 164, 33.4, 295, 336, 634, 236, 1572, and 546 mg kg−1, respectively. Mean concentrations of all the heavy metals in urban area soil were higher than the WHO permissible limits. Correlation coefficient analysis showed positive correlation among Cd, Co, Cu, Ni, and Pb, whereas no obvious correlation for Cr and Mn was found with any other heavy metal. Zn was positively correlated with Co, Ni, and Mn, whereas negative correlation was found with Cr. Results showed that Pir Wadhai and COD were the most and least contaminated parts of the city, respectively, and this is attributed to the presence and absence of heavy traffic loads and industrial effluents.ᅟ [ABSTRACT FROM AUTHOR]