Organic Ion-Associate Phase Microextraction/Back-Microextraction for Preconcentration: Determination of Nickel in Environmental Water Using 2-Thenoyltrifluoroacetone via GF-AAS

An ion-associate phase (IAP) microextraction/ back-microextraction system was applied for the enrichment, separation, and detection of trace amounts of nickel from environmental water samples. Thenoyltrifluoroacetone (HTTA) acted not only as a chelating reagent for nickel, but also as a component of the extraction phase, i.e., IAP. Nickel in a 40 mL sample solution was pH-adjusted with phenolsulfonate (PS−) and tetramethylammonium hydroxide and converted by chelation reaction in the presence of thenoyltrifluoroacetonate (TTA−). When benzyldodecyldimethylammonium ion (C12BzDMA+) was added, a suspension of IAP formed in the solution. The IAP consisted of TTA−, a chelating reagent, the PS−, a component of pH buffer, and C12BzDMA+, which helps extract the chelating complex. When the solution was centrifuged, the IAP separated from the suspension and the nickel-TTA chelate was extracted into the bottom phase of the centrifuge tube. After the aqueous phase was taken away, 100 µL of nitric acid (2 M) solution containing phosphate was used to back-microextract nickel from the IAP. The acid phase was measured via graphite-furnace atomic-absorption spectrometry (GF-AAS). The proposed method facilitated a 400-fold enrichment. The limit of detection was 0.02 µg L−1. The proposed method was applied for the determination of nickel in river water and seawater samples.

Atmospheric Monitoring of PM₂.₅, PM₁₀₋₂.₅, PM₁₀, Arsenic and Carbonaceous Aerosol at Wainuiomata

<p>Air pollution is harming our health and that of our children and parents. Air pollution causes many harmful effects, ranging from premature death, to headaches, coughing and asthma attacks. Previous studies (2008-2009) of particulate matter at Wainuiomata, Lower Hutt showed that biomass burning was primarily responsible for peak PM₂.₅ and PM₁₀ concentrations and exceedances of the National Environmental Standard (NES) and the New Zealand Ambient Air Quality Guidelines (NZAAQG). Arsenic was also found to be associated with biomass burning sources during winter at Wainuiomata. The source of arsenic was considered to be due to the use of copper chromium arsenate (CCA) treated timber as solid fuel for fires for domestic heating. While particulate matter pollution from domestic fires itself presents a health risk for the exposed population, the addition of arsenic to the mix enhances the potential risk. The use of CCA treated timber was unlikely to be used on a regular basis hence the peak arsenic concentrations did not always coincide with peak contributions from domestic fires and that the use of CCA – treated timber is more intermittent and opportunistic. This work compared several different analytical methodologies for the determination of arsenic in air particulate matter. The primary purpose was to use a standard analytical method as recommended by the NZAAQ guidelines and compare those results with the Ion Beam Analysis (IBA) and X-ray Fluorescence Spectroscopy (XRF) methods used to determine arsenic concentrations in previous studies. Through this collaborative research with GNS Science and GWRC, it was found that annual PM₁₀ and PM₂.₅ averages were well within the NZAAQG values of; 20 μg m⁻³ and 10 μg m⁻³ respectively. There was a much correlated seasonal and temporal variations observed for black carbon (BC), PM₂.₅ and arsenic concentrations. The overall concentrations of BC, PM₂.₅ and PM₁₀ have decreased significantly in the Wainuiomata airshed compared to previous studies as reported in 2009 with fewer exceedances of the NES and NZAAQG on a 24 hour daily average. The overall weighted mean arsenic concentration as measured by GF-AAS was 6.3 ± 0.8 ng m⁻³ and that measured by XRF and IBA was 3.8 ± 2.0 ng m⁻³ and 3.1 ± 5.9 ng m⁻³ respectively. The XRF and IBA arsenic concentrations were consistently lower than that of GF-AAS. The two annual arsenic averages (GF-AAS) were 6.5 ± 0.9 ng m⁻³ and 5.9 ± 0.7 ng m⁻³ respectively, for the entire sampling period. In both the cases the NZAAQG value of 5.5 ng m⁻³ were exceeded. The exceedance in the second year of sampling was not statistically significant as the guideline value 5.5 ngm⁻³ falls within the given uncertainty of the measured annual averages for arsenic. However, it is definitely an area of concern as the overall arsenic concentrations during winter periods was 12.2 ± 1.0 ng m⁻³. Moreover, burning CCA treated timber is effectively banned through regional plan rules and the problem presents itself as one of enforcement and/or public education. The inter-method comparison showed that IBA technique can be used for “screening” purposes due to high limit of detection (LOD) and analytical noise. While XRF can still be used interchangeably with GF-AAS but with Teflon or thinner filter membrane, for long term environmental monitoring of arsenic and other elemental compositions. Given the excellent recoveries of 99.2 ± 0.8% for duplicate spiked analysis and 102.7 ± 0.9% for lab blank filters spiked analysis, at 95% confidence intervals, GF-AAS method is highly reproducible and should be used in the determination of arsenic in ambient air for the purpose of comparing with the NZAAQG values.</p>

Atmospheric Monitoring of PM₂.₅, PM₁₀₋₂.₅, PM₁₀, Arsenic and Carbonaceous Aerosol at Wainuiomata

<p>Air pollution is harming our health and that of our children and parents. Air pollution causes many harmful effects, ranging from premature death, to headaches, coughing and asthma attacks. Previous studies (2008-2009) of particulate matter at Wainuiomata, Lower Hutt showed that biomass burning was primarily responsible for peak PM₂.₅ and PM₁₀ concentrations and exceedances of the National Environmental Standard (NES) and the New Zealand Ambient Air Quality Guidelines (NZAAQG). Arsenic was also found to be associated with biomass burning sources during winter at Wainuiomata. The source of arsenic was considered to be due to the use of copper chromium arsenate (CCA) treated timber as solid fuel for fires for domestic heating. While particulate matter pollution from domestic fires itself presents a health risk for the exposed population, the addition of arsenic to the mix enhances the potential risk. The use of CCA treated timber was unlikely to be used on a regular basis hence the peak arsenic concentrations did not always coincide with peak contributions from domestic fires and that the use of CCA – treated timber is more intermittent and opportunistic. This work compared several different analytical methodologies for the determination of arsenic in air particulate matter. The primary purpose was to use a standard analytical method as recommended by the NZAAQ guidelines and compare those results with the Ion Beam Analysis (IBA) and X-ray Fluorescence Spectroscopy (XRF) methods used to determine arsenic concentrations in previous studies. Through this collaborative research with GNS Science and GWRC, it was found that annual PM₁₀ and PM₂.₅ averages were well within the NZAAQG values of; 20 μg m⁻³ and 10 μg m⁻³ respectively. There was a much correlated seasonal and temporal variations observed for black carbon (BC), PM₂.₅ and arsenic concentrations. The overall concentrations of BC, PM₂.₅ and PM₁₀ have decreased significantly in the Wainuiomata airshed compared to previous studies as reported in 2009 with fewer exceedances of the NES and NZAAQG on a 24 hour daily average. The overall weighted mean arsenic concentration as measured by GF-AAS was 6.3 ± 0.8 ng m⁻³ and that measured by XRF and IBA was 3.8 ± 2.0 ng m⁻³ and 3.1 ± 5.9 ng m⁻³ respectively. The XRF and IBA arsenic concentrations were consistently lower than that of GF-AAS. The two annual arsenic averages (GF-AAS) were 6.5 ± 0.9 ng m⁻³ and 5.9 ± 0.7 ng m⁻³ respectively, for the entire sampling period. In both the cases the NZAAQG value of 5.5 ng m⁻³ were exceeded. The exceedance in the second year of sampling was not statistically significant as the guideline value 5.5 ngm⁻³ falls within the given uncertainty of the measured annual averages for arsenic. However, it is definitely an area of concern as the overall arsenic concentrations during winter periods was 12.2 ± 1.0 ng m⁻³. Moreover, burning CCA treated timber is effectively banned through regional plan rules and the problem presents itself as one of enforcement and/or public education. The inter-method comparison showed that IBA technique can be used for “screening” purposes due to high limit of detection (LOD) and analytical noise. While XRF can still be used interchangeably with GF-AAS but with Teflon or thinner filter membrane, for long term environmental monitoring of arsenic and other elemental compositions. Given the excellent recoveries of 99.2 ± 0.8% for duplicate spiked analysis and 102.7 ± 0.9% for lab blank filters spiked analysis, at 95% confidence intervals, GF-AAS method is highly reproducible and should be used in the determination of arsenic in ambient air for the purpose of comparing with the NZAAQG values.</p>

Study of Controlled Migration of Cadmium and Lead Into Foods From Plastic Utensils for Children

Lead is a highly neurotoxic chemical element known for reducing intelligence quotient (IQ) and promoting antisocial behavior in children and adolescents, while cadmium is a carcinogenic bioaccumulative element. Contaminated foods and beverages are the most common routes of exposure. The objective of this study was to determine Cd and Pb concentrations in colored plastic utensils for use by children and to measure the specific migration of these elements into beverages and foods. Pb and Cd concentrations were determined using a handheld XRF. Specific migration tests were conducted using the simulant solutions. Migration levels were determined by ICP-MS and migration tests for Pb were also performed on actual samples GF-AAS determination. Utensils (n=87) were purchased for containing Cd and/or Pb concentrations above permitted limits. The mean of Pb and Cd were 1110 and 338 ppm respectively. For specific migration assays, Pb levels were 187, 13 and 380 times above the permitted limit for acetic acid, water and orange juice, respectively. Cd levels 50 and 2.4 times above the permitted limit for acetic acid and water, respectively. The districts where the utensils were purchased were grouped according to their Social Vulnerability Index and compared using ANOVA. Results revealed a group difference in mean Pb levels for low versus medium/high social vulnerability (p = 0.006). The findings corroborate the initial hypothesis that these utensils constitute a major source of exposure to PTEs such as Cd and Pb.

DETECTION AND SAFETY AWARENESS OF HEAVY METALS IN COSMETIC PRODUCTS FREQUENTLY USED IN SAUDI ARABIA

Background: Heavymetalscontaminationincosmeticproducts isbecoming animportant healthprobleminboth worldwide and locally at the level of the Kingdom of Saudi Arabia (KSA).The aim of this study was to detectthe concentration of heavy metals in the most commonly used eyeliners purchased in Saudi Arabia. Also, to assesssafetyawarenessoftoxicelementsofmostconcernheavymetalsin cosmetics. Methods: A cross-sectional survey was designed and distributed electronically in Saudi Arabia in November 2015.The questionnairewas conducted on 769 Saudi women aged from15-60 years old that is using cosmetic products. Secondly, 10samples from 10 different types of eyeliners frequently used in Saudi Arabia were digested. The digested sampleswere analyzed for lead, cadmium andmercury using graphite furnace- atomic absorption spectrometry (GF-AAS). Results:Themajorityofcosmetictypesusedbyparticipantswereeye-linerkohl(73.9%).About(34.59 %) of participants were not aware about heavy metals contents in cosmetics. The heavy metals, cadmium, lead andmercury were detected in all samples with varying concentrations. The level of lead was the highest. There was asignificant difference of cadmium, lead and mercury concentration p< (0.05) in different brands of eyeliner. Therewasstatisticallysignificant difference betweencadmiumandlead alsobetweenmercuryandlead p<0.05ofdifferenteyelinerbrands. Conclusion: It was foundthatthemajorityofparticipantsexpectedthatexpensivecosmeticsaresafe and theypreferred internationalbrandswhichisnotnecessarytobesafe.

Hipoplasia e traços de chumbo no esmalte dentário superficial: relato de 2 casos

A presença do chumbo na composição química do esmalte dentário pode gerar hipoplasias, aumentar o risco de desmineralização e cárie. A partir de um grupo original de 17 participantes, foram determinados e comparados os resultados de níveis prévios de chumbo no esmalte dentário superficial saudável e no esmalte afetado por hipoplasia em 2 casos. Foram realizadas microbiópsias ácidas in vivo de esmalte dentário superficial, analisadas por espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES) para determinação do fósforo (P) e espectrometria de absorção atômica de forno de grafite (GF AAS) para determinação do chumbo (Pb). Caso 1: O teor de P na solução ácida referente ao esmalte saudável foi 25.200 mgP/L ± 0.200 e na solução referente à hipoplasia foi 16.400 mgP/L ± 0.100. O nível de chumbo na área de esmalte saudável foi de 20.02 ppm e 18.04 ppm na área de hipoplasia. Caso 2: O teor de P na solução ácida referente ao esmalte saudável foi 35.800 mgP/L ± 0.300 e na solução referente à hipoplasia foi 2.720 mgP/L ± 0.030. O nível de chumbo na área de esmalte saudável foi de 4.37 ppm e 236.69 ppm na área de hipoplasia. Houve diferença estatisticamente significativa em relação ao teor de fósforo e profundidade da biópsia na comparação das médias entre os dois casos de hipoplasia e esmalte saudável do grupo de origem dos casos.

Gene Variants Determine Placental Transfer of Perfluoroalkyl Substances (PFAS), Mercury (Hg) and Lead (Pb), and Birth Outcome: Findings From the UmMuKi Bratislava-Vienna Study

Prenatal exposure to perfluoroalkyl substances (PFAS), bisphenol A (BPA), lead (Pb), total mercury (THg), and methylmercury (MeHg) can affect fetal development. Factors influencing placental transfer rate of these toxins are poorly investigated. Whether prenatal exposure to pollutants has an effect on birth weight is incompletely understood. We therefore aimed (1) to determine placental transfer rates of PFAS, BPA, Pb, THg, and MeHg, (2) to analyze relationships between fetal exposure and birth outcome and (3) to analyze gene variants as mediators of placental transfer rates and birth outcome. Two hundred healthy pregnant women and their newborns participated in the study. BPA, 16 PFAS, THg, MeHg, and Pb were determined using HPLCMS/MS (BPA, PFAS), HPLC-CV-ICPMS (MeHg), CV-AFS (THg), and GF-AAS (Pb). Questionnaires and medical records were used to survey exposure sources and birth outcome. 20 single nucleotide polymorphisms and two deletion polymorphisms were determined by real-time PCR from both maternal and newborn blood. Genotype-phenotype associations were analyzed by categorical regression and logistic regression analysis. Specific gene variants were associated with altered placental transfer of PFAS (ALAD Lys59Asn, ABCG2 Gln141Lys), THg (UGT Tyr85Asp, GSTT1del, ABCC1 rs246221) and Pb (GSTP1 Ala114Val). A certain combination of three gene polymorphisms (ABCC1 rs246221, GCLM rs41303970, HFE His63Asp) was over-represented in newborns small for gestational age. 36% of Austrian and 75% of Slovakian mothers had levels exceeding the HBM guidance value I (2 μg/L) of the German HBM Commission for PFOA. 13% of newborns and 39% of women had Ery-Pb levels above 24 μg/kg, an approximation for the BMDL01 of 12 μg/L set by the European Food Safety Authority (EFSA). Our findings point to the need to minimize perinatal exposures to protect fetal health, especially those genetically predisposed to increased transplacental exposure.