Strategies to overcome interferences in elemental and isotopic geochemical analysis by quadrupole inductively coupled plasma mass spectrometry: A critical evaluation of the recent developments.

Quadrupole Inductively Coupled Plasma Mass Spectrometry (ICP-MS) instruments were introduced into geochemical and mineral exploration laboratories nearly four decades ago, providing a technique that could meet their longstanding requirement for the precise and accurate determination of several groups of trace elements and isotopes in geological materials such as rocks, minerals, ores, soils, sediments, and natural water samples. Despite its popularity among geochemists, the technique suffered from spectral and non-spectral interferences some of which seriously affected the quality of the data generated. These interferences have also had a significant impact on the ability of ICP-MS systems to achieve low detection limits. Over the last three decades, technical advances such as the development of high-resolution (HR)-ICP-MS, cool plasma, collision/reaction cell technology (CCT), dynamic reaction cell (DRC) technology, collision reaction interface (CRI), kinetic energy discrimination (KED), tandem mass spectrometry (ICP-MS/MS)/triple quadrupole ICP-MS, and multi-quadrupole ICP-MS have been introduced to eliminate/minimize many of these interferences, with each technique having its strengths and limitations. These technologies have extended the range of elements that can be measured accurately not only in geological materials, but also in several other matrices, with lower detection limits than before. In addition, other methods such as internal standardization, isotope-dilution, standard addition and matrix-matching calibrations have contributed to improving the quality of the data. This paper provides a review of these new developments from the geochemical analysis point of view.

Assessment of heavy metal contamination of road dusts from industrial areas of Hyderabad, India.

Road dust in industrial areas carries high levels of toxic heavy metals. Exposure to such polluted dust significantly affects the health of people residing in these areas, which is of major concern. The present study was taken up with an aim to highlight the magnitude and potential sources of accumulation of heavy metals in 32 road dust samples collected from six industrial areas of Hyderabad. Acid-digested sample solutions were analyzed by ICP-MS for Cu, Zn, Cr, Co, Pb, Ni, V, Zr, Ce, Y, and Hf. The road dusts exhibit significantly high mean metal levels which are much above their crustal abundances. The relative ordering of mean metal contents is Zr > Zn > Pb > Cr > Ce > Cu > V > Ni > Y > Co > Hf. Elevated pollution indices (I geo, EF, C (i) f, and C deg) reveal that the road dusts are pollution impacted showing varying degree of heavy metal contamination. Strong positive correlations exhibited by metal pairs Cu-Zn, Cr-Ni, Ce-V, Y-Ce, and Hf-Zr imply their origin from common anthropogenic sources. Principal component analysis grouped the metals according to the sources which contributed to their accumulation. The present study confirms to an intensive anthropogenic impact on the accumulation of heavy metals in the studied road dusts attributable mainly to strong influences of vehicular and industrial activity and partly to domestic and natural processes. The results obtained imply the need for further investigations to assess their ecological implications and human health risks.

ASSESSMENT OF AGE-DEPENDENT RADIATION DOSE DUE TO INTAKE OF URANIUM AND THORIUM IN DRINKING WATER FROM SIKAR DISTRICT, RAJASTHAN, INDIA.

The concentrations of 238U and 232Th have been determined in drinking water samples collected from the Sikar district of Rajasthan State, India. The samples have been analysed by using high-resolution inductively coupled plasma mass spectrometry. 238U content in water samples ranged from 8.20 to 202.63 µg l-1 and 232Th content ranged from 0.57 to 1.46 µg l-1 The measured 238U content in 25 % of the analysed samples exceeded the World Health Organization (WHO) and United States Environmental Protection Agency drinking water guidelines of 30 µg l-1 and 12.5 % of the samples exceeded the 60 µg l-1 Indian maximum acceptable concentration recommended by the Atomic Energy Regulatory Board, India. The annual effective doses (µSv y-1) due to ingestion of 238U and 232Th for different age groups were also calculated. The results compared with the recommended value reported by the WHO.

Biomonitoring of airborne platinum group elements in urban traffic police officers.

In the present study, an attempt was made to study the levels of platinum (Pt), palladium (Pd), and rhodium (Rh) in respirable suspended particulate matter samples and respective blood samples of occupationally exposed traffic personnel in selected sites of Hyderabad city. The maximum concentration of platinum group elements in air dust samples of Hyderabad city were as follows: Pt = 1,416 µg/m(3), Pd = 1,024 µg/m(3), and Rh = 1,352 µg/m(3). The blood samples of occupationally exposed personnel of Hyderabad city showed Pt as high as 6.65, Pd as high as 2.15, and Rh as high as 4.95 µg/l. The results showed an important aspect of bioaccumulation tendency of these metals with increase in age and years of occupational exposure.

Application of microwave plasma atomic emission spectrometry (MP-AES) for environmental monitoring of industrially contaminated sites in Hyderabad city.

Recently introduced microwave plasma-atomic emission spectroscopy (MP-AES) represents yet another and very important addition to the existing array of modern instrumental analytical techniques. In this study, an attempt is made to summarize the performance characteristics of MP-AES and its potential as an analytical tool for environmental studies with some practical examples from Patancheru and Uppal industrial sectors of Hyderabad city. A range of soil, sediment, water reference materials, particulate matter, and real-life samples were chosen to evaluate the performance of this new analytical technique. Analytical wavelengths were selected considering the interference effects of other concomitant elements present in different sample solutions. The detection limits for several elements were found to be in the range from 0.05 to 5 ng/g. The trace metals analyzed in both the sectors followed the topography with more pollution in the low-lying sites. The metal contents were found to be more in ground waters than surface waters. Since a decade, the pollutants are transfered from Patancheru industrial area to Musi River. After polluting Nakkavagu and turning huge tracts of agricultural lands barren besides making people residing along the rivulet impotent and sick, industrialists of Patancheru are shifting the effluents to downstream of Musi River through an 18-km pipeline from Patancheru. Since the effluent undergoes primary treatment at Common Effluent Treatment Plant (CETP) at Patanchru and travels through pipeline and mixes with sewage, the organic effluents will be diluted. But the inorganic pollutants such as heavy and toxic metals tend to accumulate in the environmental segments near and downstreams of Musi River. The data generated by MP-AES of toxic metals like Zn, Cu, and Cr in the ground and surface waters can only be attributed to pollution from Patancheru since no other sources are available to Musi River.

Uranium estimation in drinking water samples from some areas of Punjab and Himachal Pradesh, India using ICP-MS.

The uranium concentration in drinking water samples collected from areas of Punjab and Himachal Pradesh has been measured using inductively coupled plasma mass spectrometry. The sources of water comprise hand pumps and tube wells. The uranium concentration lies in the range of 1.24-45.42 µg l(-1) with a mean value of 14.91 µg l(-1) in drinking water samples from Punjab and 0.56-10.11 µg l(-1) with a mean value of 2.17 µg l(-1) in Himachal Pradesh. The measured uranium content in 4 % water samples from Punjab has been found to be higher than the limit of 30 µg l(-1) recommended by the World Health Organization (WHO) and US Environmental Protection Agency. However, the uranium concentration in all the water samples from Himachal Pradesh is well below the recommended limit. The annual effective dose associated with drinking water due to uranium concentration is estimated from its annual intake using dosimetric information based on International Commission on Radiological Protection 72. The resulting value of the annual effective dose from drinking water sources is in the range of 0.33-37.78 µSv, which is well within the limit of 100 µSv recommended by the WHO.

Analysis of uranium concentration in drinking water samples using ICPMS.

Uranium concentration in drinking water samples collected from some areas of Northern Rajasthan has been measured using inductively coupled plasma mass spectrometry. The water samples were taken from hand pumps. The uranium concentration in water samples varies from 2.54-133.0 µg L with a mean value of 38.48 µg L. The uranium concentration in most of the drinking water samples exceeds the safe limit (30 µg L) recommended by the World Health Organization. The annual effective dose associated with drinking water due to uranium concentration is estimated from its annual intake using dosimetric information based on ICRP 72. The resulting value of the annual effective dose from drinking water sources is in the range of 2.11-110.45 µSv. The annual effective dose in one of the samples was found to be greater than WHO-recommended level of 100 µSv y.

Assessment of the effects of municipal sewage, immersed idols and boating on the heavy metal and other elemental pollution of surface water of the eutrophic Hussainsagar Lake (Hyderabad, India).

The surface water qualities of Hussainsagar, an eutrophic urban lake in the midst of twin cities of Hyderabad and Secunderabad (India) receiving large quantities of external inputs--both untreated municipal sewage containing industrial effluents, and treated sewage, a large number of annually immersed idols of God and Goddess, and intense boating activities were assessed in relation to the concentration of elements including heavy metals of the water along the necklace road of the lake. Elemental analyses of water using ICP-MS revealed 26 elements including heavy metals--As, Cd, Cr, Ni, Pb, Cu, Fe, Mn, Se, Ba, Zn, Mo, V, Co, Ag, Sr, Rb, Mg, K, Ca, Al, Si, Sb, Na, Li, and B, in the surface water of the lake. Of these, the first 15 elements were found in elevated concentrations in the water at the outfall point of the untreated municipal sewage (site 3), which was the main dominating source of contamination of the lake water while Cu and Sb were recorded in higher concentrations at the outfall of treated effluent from Sewage Treatment Plant, and three elements (Ba, Si, and B) were in higher concentration at the sites of outfall of sewage flowing from an oxygenated pond (site 4), Ca, Zn, and Sr, at the site immersed with idols (site 1), and Pb, Ag, and Al at the center of the lake (site 5) with intense boating activities. Concentrations of most of these elements exceeded the maximum permissible limits of national (Indian Council Medical Research) standards for drinking water. The concentrations of most of the elemental contaminants showed significant positive correlations between them.

Potential of Hemidesmus indicus for phytoextraction of lead from industrially contaminated soils.

Many sites in the industrial region of Kattedan near Hyderabad, Andhra Pradesh (AP), India are contaminated with high concentrations of lead. The use of plants to remove toxic metals from soils (phytoremediation) is emerging as a potential strategy for cost-effective and environmentally sound remediation of contaminated soils. We studied remediation of soils contaminated with lead using a lead hyperaccumulating plant, Hemidesmus indicus. The ability of this plant to accumulate lead in shoots and roots was studied with pot experiments. The results showed that accumulation was maximum in roots for the first 1-3 weeks and later for a contact period of three months, the accumulation rate was maximum in shoots. In addition we used various chelating agents such as EDTA, HEDTA, DTPA and CDTA to determine the best chemical modifier for efficient lead removal from contaminated soils. The effect on lead accumulation of plant in the presence of various metal co-ions was also studied. An attempt was made for the decontamination of lead from five different "Real-life" soils of Kattedan using H. indicus.

Risk assessment and pathway study of arsenic in industrially contaminated sites of Hyderabad: a case study.

Different areas in the industrial region of Patancheru near Hyderabad, Andhra Pradesh (A.P), India are contaminated with high concentration of arsenic, which is attributed to industrial source like veterinary chemicals, pharmaceuticals, pesticide industries, etc. Fourteen villages of this area of Patancheru were assessed for arsenic contamination by collecting samples of water (surface and ground), soil, fodder, milk, and vegetables. The total arsenic content in the whole blood, urine, hair, and nails of the residents showing arsenical skin lesions and other clinical manifestations were also studied. To understand the bioavailability of arsenic in this environment and its possible entry into human food chain, speciation studies of arsenic was carried out and the results are presented in this paper.

Inorganic arsenic species in groundwater: a case study from Purbasthali (Burdwan), India.

A regional groundwater quality survey from 20 tube wells in the Purbasthali area of the Burdwan district of West Bengal province (India) identified arsenic pollution in this area. Arsenic was detected in 19 cases at a concentration level 0.5 to 135.9 micrograms/L. Speciation studies indicate that As(III) is present in only one sample and organo-arsenic compounds have not been detected. Iron, antimony and pH of such water samples were also studied to see if there is any correlation of the presence of arsenic and these parameters. A high concentration of iron (0.3 to 10.7 mg/L) has been detected. Antimony is present in all these water samples (0.03 to 0.9 microgram/L). The pH value of the groundwater in this area shows that it is more or less neutral.

Comparitive study of the sample decomposition procedures in the determination of trace and rare earth elements in anorthosites and related rocks by ICP-MS.

ICP-MS has been used for the determination of over 30 geochemically significant trace elements (Sc, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Cs, Ba, Hf, Ta, Pb, Th, U and REEs) in anorthosites and related rock reference samples. Open acid digestion, pressure decomposition using HF, HNO(3) and HClO(4), and a fusion method using lithium metaborate and subsequent dissolution in dil. HNO(3) were adopted for the decomposition of these rock samples before analysis. The dissolution problems and interference effects are discussed. Rh and Bi were used as internal standards. The first set of data on several rare earths and other trace elements in the Russian anorthosite reference sample, MO-6 are presented along with data on other samples. The data are compared with the available data. The results obtained with different dissolution methods were found to be in good agreement for the majority of the trace elements. The accuracy and precision achieved (better than 6% RSD in most cases) suggested that the data obtained by ICP-MS for such samples are best suited for geochemical interpretations.