Production of the broad specific monoclonal antibody against sarafloxacin for rapid immunoscreening of 12 fluoroquinolones in meat

The objective of this study was to produce a generic antibody for immunoassay of fluoroquinolone drugs in meat. Two novel haptens of sarafloxacin were synthesized that were used to produce the monoclonal antibodies. The obtained monoclonal antibodies simultaneously recognized 12 fluoroquinolone drugs (sarafloxacin, diflocaxin, marbofloxacin, ofloxacin, ciprofloxacin, enrofloxacin, norfloxacin, pefloxacin, lomefloxacin, amifloxacin, enofloxacin and danofloxacin). After evaluation of different coating antigen/antibody combinations, a heterologous competitive indirect enzyme linked immunosorbent assay (ELISA) was developed to determine the 12 drugs. The crossreactivities to these analytes were in the range of 18%–113% and the limits of detection were in the range of 0.8–6.5 ng/mL depending on the compound. Eight fluoroquinolones licensed as veterinary drugs in China were fortified into blank chicken for ELISA analysis. The recoveries were in the range of 67.6%–94.6% with coefficients of variation lower than 12.4%. Therefore, this method could be used as a screen tool for routine monitoring of the residues of these fluoroquinolone drugs in animal derived foods.     

Synthesis of novel hapten and production of generic monoclonal antibody for immunoassay of penicillins residues in milk

The objective of this study was to produce a generic monoclonal antibody for determination of penicillins residues in milk. The compound 6-aminopenicillanic acid was used as the template to synthesize two novel generic haptens that were used to produce the monoclonal antibodies. The obtained monoclonal antibodies simultaneously recognized 11 penicillin drugs (amoxicillin, ampicillin, penicillin G, penicillin V, sulbenicillin, carbencillin, methicillin, cloxacillin, dicloxacillin, oxacillin, and nafcillin). After evaluation of different reagent combinations, a heterologous indirect competitive enzyme immunoassay was developed to multi-determine the 11 drugs in milk. The crossreactivities to the 11 drugs were in a range of 16%–117% and the limits of detection were in a range of 0.7–9.3 ng/mL depending on the drug. The recoveries from the fortified blank milk were in a range of 77.6%–99.4% with coefficients of variation lower than 13.5%. This method could be used as a rapid screen tool for routine monitoring the residues of the 11 penicillin drugs in animal derived foods.     

Production of monoclonal antibody against doxycycline for immunoassay of seven tetracyclines in bovine muscle and milk

The objective of this study was to produce a generic monoclonal antibody for multi-determination of the residues of tetracycline drugs in bovine muscle and milk. Two new immunogens of doxycycline were prepared that were used to produce the monoclonal antibodies. Results showed the obtained antibodies simultaneously recognized seven tetracycline drugs (doxycycline, tetracycline, chlortetracycline, oxytetracycline, minocycline, methacycline, demeclocycline). The obtained antibodies and three coating antigens were arranged into six combinations to optimize the reagents combination. After comparison of the performances of these combinations, a heterologous indirect competitive ELISA was then used to determine the seven tetracyclines in bovine muscle and milk. The crossreactivities to the seven analytes were in the range of 47%–102% and the limits of detection were in the range of 1.5–6.9 ng/mL depending on the compound. The recoveries of the seven drugs from fortified blank samples were in the range of 75.3%–106.8% with coefficients of variation lower than 10.9%. Therefore, this method could be used as a multi-analytes screen tool for routine monitoring of the residues of these tetracycline drugs in bovine muscle and milk.     

Production of the monoclonal antibody against tylosin for immunoassay of macrolide antibiotics in milk

The objective of the present study was to develop an immunoassay for multi-determination of the residues of four macrolide antibiotics in milk. Tylosin was derivatized with 6-aminohexanoic acid to synthesize a hapten that was used to produce the monoclonal antibody. The obtained monoclonal antibody simultaneously recognized tylosin, acetylisovaleryltylosin, tilmicosin and desmycosin with crossreactivities of 100%, 91%, 49% and 76%, respectively. Then an indirect competitive immunoassay was developed to determine the four analytes in milk simultaneously. The limits of detection for the four analytes were in the range of 5.5–11.7 ng/mL depending on the compound. The recoveries of the four analytes from fortified blank milk were in the range of 78%–96% with coefficients of variation lower than 11.4%. The developed immunoassay could be used as a practical tool for rapid screening the residues of the four anlytes in milk.     

Development of a sensitive,competitive, indirect ELISA for the detection of fumonisin B1 in corn originating from Anhui province,China

Fumonisin B₁ (FB₁) is a secondary metabolite produced by Fusarium verticillioides or Fusarium proliferatum, which present in food and feed. It causes hazardous effects on human and animal health. A monoclonal antibody (mAb) against FB₁ was produced and a simple, reliable and sensitive, competitive, indirect enzyme-linked immunosorbent assay (ci-ELISA) for detection of FB₁ was developed and the experiment conditions were optimized. The coating concentration of FB₁-ovalbumin (FB₁-OVA) was 500 ng mL^?1, the action concentrations of anti-FB₁ mAb and goat anti-mouse IgG were 1.28 × 10⁴ and 1:5000, respectively. The 50% inhibitory concentration (IC₅₀) was 11 ng mL^?1, with a detectable range of 1.25–250 ng mL^?1, and a limit of determination (LOD) of 1.15 ng mL^?1. The cross-reactivity (CR) of the antibody against fumonisin B₂ (FB₂) was 60.4, and <1% against deoxynivalenol (DON), aflatoxin B₁ (AFB₁), ochratoxin A (OTA) or zearalenone (ZEN). In spiked samples (250 ng g^?1, 500 ng g^?1, 1000 ng g^?1), the mean recoveries ranged from 86.7 ± 5% to 102 ± 4%, and the coefficient of variation (CV) ranged from 3% to 10%. A survey of 96 corn samples from Bozhou, Fuyang, Bengbu, and Hefei, in Anhui province, China, was performed. Frequencies of FB₁ contamination were 83.3%, 95.8%, 20.8% and 91.7%, and the mean concentrations of positive samples were 0.702 μg kg^?1, 0.883 μg kg^?1, 0.074 μg kg^?1, and 0.276 μg kg^?1, respectively. The results of this study suggest that the ci-ELISA developed in this study can be used to identify FB₁ in corn, furthermore, further study is needed to investigate FB₁ contamination in food and feed to prevent its harmful health effects.     

Immunoassay of red dyes based on the monoclonal antibody of β-naphthol

The objective of the present study was to develop a multi-analyte immunoassay for the determination of eight red dyes in food samples. Two dye intermediates (2-hydroxy-1-naphthoic acid and 1-amino-2-naphthol) were used as the haptens to produce the monoclonal antibodies. The obtained monoclonal antibodies recognized Sudan 1–4, Para red, Sudan red G, Sudan red B and Acid orange II simultaneously. After evaluation of different antibody/coating antigen combinations, a heterologous indirect competitive enzyme linked immunosorbent assay was developed to determine the eight red dyes in food samples (chili oil, chili powder, tomato sauce, hotpot seasoning). The crossreactivities to the eight analytes were in the range of 61%–79% (with β-naphthol as 100%), and the limits of detection were in the range of 1.3–1.9 ng/mL. The recoveries of the eight analytes from the fortified blank samples were in the range of 84.2%–115% with coefficients of variation lower than 18.3%. Therefore, this method could be used as a rapid and simple tool to detect the residues of the eight red dyes in foods.     

Multivariate characterization of elements accumulated in Wolfiporia extensa mushroom from Yunnan province of China

ABSTRACT

Dried sclerotia of Wolfiporia extensa have been used as medicine in Asia from Eastern Han Dynasty, and also used as traditional snack called “fulingjiabing” in Beijing, China. In this paper, 18 macro and trace elements (Ag, As, Ba, Cd, Co, Cr, Cs, Cu, Fe, Li, Mn, Ni, Pb, Rb, Se, Sr, V, and Zn) in both flesh and peel of Wolfiporia extensa from seven sites of Yunnan province in China were determined by inductively coupled plasma mass spectrometer. The average recovery rates of certified reference materials for GBW10015 (spinach leaves) ranged from 90.5 to 113%, for GBW10028 (citrus leaves) from 92.8 to 106%, and for GBW07603 (bush branch and leaves) from 83.3 to 114.6%. Generally speaking, the concentration of all elements determined was at common level. The results of this survey indicate that mineral compositions in peel were higher than in flesh. In peel, the contents of investigated trace metals in mushroom samples were found to be in the range of 1,660–13,400 µg·g^?1 dry matter (dm) for Fe and 29.6–710 µg·g^?1 dm for Mn. The mean contents of Cr, Cu, Rb, V, and Zn in peel were between 10 and 20 µg·g^?1 dm, followed by As, Co, Li, Ni, Pb, Se, and Sr with mean contents between 1 and 10 µg·g^?1 dm, while Ag, Cd, and Cs had mean contents of <1 µg·g^?1 dm. In flesh, the concentration of Fe was in the range of 54–900 µg·g^?1 dm, and it was 1.5–49 µg·g^?1 dm for Mn, followed by Ba, Cu, Rb, and Zn in the range of 1 to 10 µg·g^?1 dm, while for Ag, As, Cd, Co, Cr, Cs, Li, Ni, Pb, Se, Sr, and V it was <1 µg·g^?1 dm. The concentration of toxic elements, such as As, Cd, and Pb, in both flesh and peel was below the permissible limits of World Health Organization. However, As and Pb contents in peel were higher than the limits permitted in the Chinese Pharmacopoeia. The results of principal component analysis showed that the flesh of Wolfiporia extensa from all the seven sites of the Yunnan province tend to cluster together, most probably because the origin of mineral elements in both flesh and peel is wood substrate (old and dead pine trees).     

Concentrations of organochlorine pesticides (OCPs) residues in foodstuffs collected from traditional markets in Indonesia

A total 23 of organochlorine pesticides (OCPs) residues were determined in five groups of foodstuffs, i.e.: vegetables (carrot, potato, cucumber, corn, and onion), rice, pulses (green bean and soybean), nuts (peanut), and fish (milkfish), which collected from traditional markets in three big cities of Indonesia; Jakarta, Bogor, and Yogyakarta. OCPs were only detected in fatty foodstuffs, such as soybean, peanut, and milkfish. The concentration of HCB (expressed as ng g^?1 on a whole basis), ΣDrins, ΣDDTs, ΣHeptachlors, and ΣHCHs were in the range of <0.3–0.74 ng g^?1, <0.03–0.42 ng g^?1, <0.02–0.41 ng g^?1, <0.03–0.14 ng g^?1, and <0.03–0.06 ng g^?1, respectively, which were far below the maximum residue limits (MRLs) as established by FAO/WHO. These very low concentrations of OCPs residues in foodstuffs indicated that OCPs were used only in past time and no recent input into the environment. Furthermore, the estimated daily intake (EDI) of HCB, ΣDDTs, ΣDrins, ΣHeptachlors, and ΣHCHs in five group foodstuffs, which were 60% of total daily diet of Indonesian, were 0.09 ng kg^?1 bw d^?1, 0.04 ng kg^?1 bw d^?1, 0.01 ng kg^?1 bw d^?1, 0.003 ng kg^?1 bw d^?1, and 0.002 ng kg^?1 bw d^?1, respectively. These results were far below the acceptable daily intake (ADI) as established by FAO/WHO, which indicated that consumption of foodstuffs from Indonesia were at little risk to human health in term of OCPs at present.     

Distribution and ecological risk of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in surface sediments from the Bizerte lagoon,Tunisia

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in 18 surface sediment samples collected from Bizerte lagoon, Tunisia. The total concentrations of ten PCBs (∑PCBs) and of four OCPs (∑OCPs) in the sediments from this area ranged from 0.8 to 14.6 ng g^?1 dw (average value, 3.9 ng g^?1 dw) and from 1.1 to 14.0 ng g^?1 dw (average value, 3.3 ng g^?1 dw), respectively. Among the OCPs, the range of concentrations of dichlorodiphenyltrichloroethane and its metabolites (DDTs) and hexachlorobenzene (HCB) were 0.3–11.5 ng g^?1 dw (1.9 ng g^?1 dw) and 0.6–2.5 ng g^?1 dw (1.4 ng g^?1 dw), respectively. Compositional analyses of the POPs indicated that PCB 153, 138 and 180 were the predominant congeners accounting for 60 % of the total PCBs. In addition, p,p′-DDT was found to be the dominant DDTs, demonstrating recent inputs in the environment. Compared with some other regions of the world, the Bizerte lagoon exhibited low levels of PCBs and moderate levels of HCB and DDTs. The high ratios ΣPCBs/ΣDDTs indicated predominant industrial versus agricultural activities in this area. According to the established guidelines for sediment quality, the risk of adverse biological effects from such levels of OCPs and PCBs, as recorded at most of the study sites, was insignificant. However, the higher concentrations in stations S1 and S3 could cause biological damage.     

Occurrence,spatial distribution,sources, and risks of polychlorinated biphenyls and heavy metals in surface sediments from a large eutrophic Chinese lake (Lake Chaohu)

Surface sediment from large and eutrophic Lake Chaohu was investigated to determine the occurrence, spatial distribution, sources, and risks of polychlorinated biphenyls (PCBs) and heavy metals in one of the five biggest freshwater lakes in China. Total concentration of PCBs (Σ₃₄PCBs) in Lake Chaohu was 672 pg g^?1 dry weight (dw), with a range of 7 to 3999 pg g^?1 dw, which was lower than other water bodies worldwide. The majority of heavy metals were detected at all sampling locations, except for Sr, B, and In. Concentrations of Al, Fe, Ca, Mn, Sr, Co, Zn, Cd, Pb, and Hg were similar to that reported for other lakes globally. Concentrations of K, Mg, Na, Li, Ga, and Ag were greater than the average, whereas those of Cr, Ni, and Cu were lower. Cluster analysis (CA) and positive matrix factorization (PMF) yielded accordant results for the source apportionment of PCBs. The technical PCBs and microbial degradation accounted for 34.2 % and 65.8 % of total PCBs using PMF, and PMF revealed that natural and anthropogenic sources of heavy metals accounted for 38.1 % and 61.8 %, respectively. CA indicated that some toxic heavy metals (e.g., Cd, In, Tl, and Hg) were associated with Ca–Na–Mg minerals rather than Fe–Mn minerals. The uncorrelated results between organic matter revealed by pyrolysis technology and heavy metals might be caused by the existence of competitive adsorption between organic matter and minerals. PCBs and heavy metals were coupling discharge without organochlorine pesticides (OCPs), but with polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs). No sediment sample exceeded the toxic threshold for dioxin-like PCBs (dl-PCBs) set at 20 pg toxicity equivalency quantity (TEQ)?g^?1, (max dl-PCBs, 10.9 pg TEQ g^?1). However, concentrations of Ag, Cd, and Hg were at levels of environmental concern. The sediment in the drinking water source area (DWSA) was threatened by heavy metals from other areas, and some fundamental solutions were proposed to protect the DWSA.     

Indoor exposure from building materials: A field study

The present study has been conducted in the frame of BUMA (Prioritization of Building Materials Emissions as indoor pollution sources), a European funded project, aiming at assessing the exposure to emitted compounds in indoor air. Field campaigns in five (5) European cities (Milan, Copenhagen, Dublin, Athens and Nicosia) were carried out. These campaigns covered weekly winter and summer concentration measurements in two (2) public buildings and two (2) private houses in each city. BTEX, terpenes, and carbonyls were measured using passive sampling in two sites inside the building and one outside. VOC emission measurements on selected building material have also been performed using Field and Laboratory Emission Cell (FLEC). The results on indoor concentrations for compounds such as formaldehyde (1.2–62.6 μg m^?3), acetaldehyde (0.7–41.6 μg m^?3), toluene (0.9–163.5 μg m^?3), xylenes (0.2–177.5 μg m^?3) and acetone (2.8–308.8 μg m^?3) have shown diversity and relatively significant indoor sources depending on the building type, age etc. Indoor concentrations of these substances are varied depending on the building age and type. The percentage of approximately 40% of the indoor air quality levels originated from building materials.     

Distribution,source, and environmental risk assessment of phthalate esters (PAEs) in water,suspended particulate matter,and sediment of a typical Yangtze River Delta City,China

Phthalates (PAEs) in drinking water sources such as the Yangtze River in developing countries had aroused widespread concern. Here, the water, suspended particulate matter (SPM), and sediment samples were collected from 15 sites in wet and dry seasons in Zhenjiang, for the determination of six PAEs (DMP, DEP, DIBP, DBP, DEHP, and DOP) using the solid-phase extraction (SPE) or ultrasonic extraction coupled with gas chromatography-mass spectrometry (GC-MS). The total concentrations of six PAEs (Σ₆PAEs) spanned a range of 2.65–39.31 μg L^?1 in water, 1.97–34.10 μg g^?1 in SPM, and 0.93–34.70 μg g^?1 in sediment. The partition coefficients (K_d1) of PAEs in water and SPM phase ranged from 0.004 to 3.36 L g^?1 in the wet season and from 0.12 to 2.84 L g^?1 in the dry season. K_d2 of PAEs in water and sediment phase was 0.001–9.75 L g^?1 in the wet season and 0.006–8.05 L g^?1 in the dry season. The dominant PAEs were DIBP, DBP, and DEHP in water and SPM, DIBP, DEHP, and DOP in sediment. The concentration of DBP in water exceeded the China Surface Water Standard. The discharge of domestic sewage and industrial wastewater might be the main potential sources of PAEs. The risk quotient (RQ) method used for the risk assessment revealed that DBP (0.01 < RQ < 1) posed a medium risk, while DIBP and DEHP (RQ > 1) posed a high environmental risk in water, DIBP (RQ > 1) also showed a high risk in sediment.

     

A voltammetric screening method to determine ronidazole in bovine meat

Abstract

An original voltammetric screening method, employing glassy carbon electrode (GCE) with the differential-pulse voltammetry technique (DPV), has been developed to determine residues of the anti-parasitic agent Ronidazole (RNZ) in bovine meat. By using cyclic voltammetry (CV), it has been demonstrated that an irreversible cathodic process occurs at approximately ?0.740?V (vs. Ag|AgCl, KCl 3?mol L^?1) in a 0.100?mol L^?1 phosphate buffer at pH 6.5 as supporting electrolyte. Furthermore, the behavior of RNZ in CV indicates the occurrence of a diffusion mass transfer process to the working electrode surface. The RNZ reduction mechanism was proposed as a 6-electron transfer, similar to Metronidazole under the same pH range. Quantification of RNZ and method validation were then carried out by DPV. The relative standard deviation (RSD) were 3.21% for intraday precision of 10 consecutive repetitions and 6.78% for interday precision after five analysis. Limits of detection and quantification were also obtained, and the values were 0.107 and 0.358?mg kg^?1, respectively. The recovery percentage for three different concentrations of RNZ in the bovine meat matrix ranged between 98.1% and 100.3%. The method proved to be efficient for screening RNZ in bovine meat.     

Quantitative modelling to estimate the transfer of pharmaceuticals through the food production system

Use of pharmaceuticals in animal production may cause an indirect route of contamination of food products of animal origin. This study aimed to assess, through mathematical modelling, the transfer of pharmaceuticals from contaminated soil, through plant uptake, into the dairy food production chain. The scenarios, model parameters, and values refer to contaminants in emission slurry production, storage time, immission into soil, plant uptake, bioaccumulation in the animal's body, and transfer to meat and milk. Modelling results confirm the possibility of contamination of dairy cow's meat and milk due the ingestion of contaminated feed by the cattle. The estimated concentration of pharmaceutical residues obtained for meat ranged from 0 to 6 ng kg^?1 for oxytetracycline, from 0.011 to 0.181 μg kg^?1 for sulfamethoxazole, and from 4.70 to 11.86 μg kg^?1 for ketoconazole. The estimated concentrations for milk were: zero for oxytetracycline, lower than 40 ng L^?1 for sulfamethoxazole, and from 0.98 to 2.48 μg L^?1 for ketoconazole. Results obtained for the three selected pharmaceuticals indicate a minor risk for human health. This study showed that supply chain modelling could be an effective tool in assessing the indirect contamination of feedstuff and animal products by residues of pharmaceuticals. The model can easily be adjusted to other contaminants and supply chain and, in this way, present a valuable tool to underpin decision making.     

Estimation and characterization of unintentionally produced persistent organic pollutant emission from converter steelmaking processes

Unintentionally produced persistent organic pollutants (UP-POPs) including polychlorinated dibenzo-p-dioxins, and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polychlorinated naphthalenes (PCNs) were characterized and quantified in stack gas and fly ash from the second ventilation systems in five typical converters in five different steelmaking plants. The 2378-substituted PCDD/Fs (2378-PCDD/Fs) and dioxin-like PCB (dl-PCBs) toxic equivalents (TEQs) were 1.84–10.3 pg WHO-TEQ Nm^?3 in the stack gas and 5.59–87.6 pg WHO-TEQ g^?1 in the fly ash, and the PCN TEQs were 0.06–0.56 pg TEQ Nm^?3 in the stack gas and 0.03–0.08 pg TEQ g^?1 in the fly ash. The concentrations of UP-POPs in the present study were generally lower than those in other metallurgical processes, such as electric arc furnaces, iron ore sintering, and secondary metallurgical processes. Adding scrap metal might increase UP-POP emissions, indicating that raw material composition was a key influence on emissions. HxCDF, HpCDF, OCDF, HpCDD, and OCDD were the dominant PCDD/Fs in the stack gas and fly ash. TeCB and PeCB were dominant in the stack gas, but HxCB provided more to the total PCB concentrations in the fly ash. The lower chlorinated PCNs were dominant in all of the samples. The 2378-PCDD/F, dl-PCB, and PCN emission factors in stack gases from the steelmaking converter processes (per ton of steel produced) were 1.88–2.89, 0.14–0.76_, and 229–759 μg t^?1, respectively.     

Anhydrosugar and sugar alcohol organic markers associated with carboxylic acids in particulate matter from incense burning

Aerosol from the burning two types of sandalwood-based incense, Hsing Shan and Lao Shan, was analyzed to characterize the chemical profile of total particulate matter emitted. The total particulate matter (PM) mass emission factors were 46.3 ± 2.68 mg g^?1 of Hsing Shan incense and 43.7 ± 1.08 mg g^?1 of Lao Shan incense. Chemical analysis of emissions from the two types of incense revealed that of the 25 components in four groups characterized, anhydrosugars formed the major group, at 46.7–52.2% w/w of the identified particulate and 1078.3–1169.8 μg g^?1 of incense, followed by inorganic salts at 30.4–31.8% w/w of identified particulate and 681.6–734.0 μg g^?1 of incense, carboxylic acids at 12.0–17.1% w/w of the identified particulate and 268.6–392.8 μg g^?1 of incense, and sugar alcohols at 4.44–5.38% w/w of the identified particulate and 102.3–120.6 μg g^?1 of incense. More anhydrosugars and sugar alcohols were emitted from Lao Shan incense than from Hsing Shan incense whereas more carboxylic acids and organic salts were emitted from Hsing Shan than from Lao Shan. These differences were due to structural and functional differences in the young sandalwood used to make Hsing Shan and the aged sandalwood used to make Lao Shan. The anhydrosugar levoglucosan, used as a marker of biomass burning, was always the most abundant species in emitted PM for both incenses (Lao Shan 21.7 mg g^?1 of PM and Hsing Shan 18.7 mg g^?1). K⁺ and Cl^? were the second most abundant components (K⁺ and Cl^? were summed), accounting for 10.6 mg g^?1 of Hsing Shan PM and 9.85 mg g^?1 of Lao Shan PM. The most abundant carboxylic acids in the emissions were formic, acetic, succinic, glutaric and phthalic acid. The latter is a fragrance ingredient and a potential health hazard and was twice as prevalent in Lao Shan emissions. Xylitol was the most prevalent of the sugar alcohols at 35.7–36.6% w/w of total identified sugar alcohols. These abundant species are potential markers for incense burning. K⁺, levoglucosan, mannosan and xylitol are already reported in discriminator ratios for wood burning and it is proposed here that these can and should also apply to incense burning. The calculated discriminator ratios for two types of incense burning reported here are 0.229–0.288 for K/Levo, 12.5–13.5 for Levo/Manno, and 21.5–23.7 for the novel discriminator ratio Levo/Xylitol.     

Ivermectin dissipation and movement from feces to soil under field conditions

The aim of this work was to evaluate the fate of ivermectin (IVM) at two concentrations in cattle feces and its movement to the nearby soil and plants. Feces were spiked with IVM at two levels: 3000 ng g^?1 (high group, HG) and 300 ng g^?1 (low group, LG). Artificial dung pats were prepared and deposited in an experimental field area. Feces and underlying soil were sampled up to 60 days post-deposition (dpd). As an additional analysis, grasses growing around the pats were sampled at 30 and 60 dpd. Ivermectin concentrations in all matrices were determined by HPLC. Mean IVM fecal concentrations were in the range between 3901.9 ng g^?1 and 2419.2 ng g^?1 (high group) and 375.3 ng g^?1 and 177.49 ng g^?1 (low group). Mean times for 50% and 90% dissipation were 88.23 and 293.03 days (HG) and 39.1 and 129.9 days (LG). Soil concentrations ranged from 26.1 ng g^?1 to 71.1 ng g^?1 (HG) and 3.4 to 5.9 ng g^?1 (LG); in plants, concentrations were between 71.4 and 380.8 ng g^?1 and 5.40 and 51.8 ng g^?1 in HG and LG, respectively. These results confirm that IVM moves from feces to the underlying soil as well as to nearby plants. The potential risk of detrimental effects on soil organisms and the impact on herbivorous animals should be further evaluated.     

Assessing the enrichment of heavy metals in surface soil and plant (Digitaria eriantha) around coal-fired power plants in South Africa

Nine metals (Fe, Cu, Mn, Ni, Cd, Pb, Hg, Cr, and Zn) were determined in soil and Digitaria eriantha plants within the vicinity of three coal power plants (Matla, Lethabo, and Rooiwal), using ICP-OES and GFAAS. The total metal concentration in soil ranged from 0.05?±?0.02 to 1836?±?70 μg g^?1, 0.08?±?0.05 to 1744?±?29 μg g^?1, and 0.07?±?0.04 to 1735?±?91 μg g^?1 in Matla, Lethabo, and Rooiwal, respectively. Total metal concentration in the plant (D. eriantha) ranged from 0.005?±?0.003 to 535?±?43 μg g^?1 in Matla, 0.002?±?0.001 to 400?±?269 μg g^?1 in Lethabo, and 0.002?±?0.001 to 4277?±?201 μg g^?1 in Rooiwal. Accumulation factors (A) of less than 1 (i.e., 0.003 to 0.37) at all power plants indicate a low transfer of metal from soil to plant (excluder). Enrichment factor values obtained (2.4–5.0) indicate that the soils are moderately enriched with the exception of Pb that had significant enrichment of 20. Geo-accumulation index (I-geo) values of metals indicate that the soils are moderately polluted (0.005–0.65), except for Pb that showed moderate to strong pollution (1.74–2.53).     

Trace phthalate and adipate esters contaminated in packaged food

A method for trace analysis of two plasticizers, di-2-ethylhexyl phthalate (DEHP) and di-2-ethylhexyl adipate (DEHA), contaminated in packaged curry paste were investigated by gas chromatography with flame ionization detector (GC-FID). Curry paste samples were extracted by ultrasonic and solid phase extraction using Florisil® cartridge. Analysis by the GC-FID system provided limits of detection for DEHA and DEHP at 12 and 25 μ g L^{? 1} and a linear dynamic range between 25 μ g L^{? 1} to 60 mg L^{? 1} with a coefficient of determination (R²) greater than 0.99. High recoveries were obtained, ranged from 91 to 99% and 88 to 98% for DEHP and DEHA with RSD lower than 7 and 10% respectively. The method detection limit and limits of quantitation were ranged from 27 to 30 and 90 to 100 μ g L^{? 1}. The analysis of curry paste samples showed concentrations of DEHP and DEHA in the range of 4.0 ng g^{? 1} to 0.61 μg g^{? 1}.     

Determinations of hexabromocyclododecane (HBCD) isomers in channel catfish, crayfish, hen eggs and fish feeds from China by isotopic dilution LC-MS/MS

HBCD is widely used brominated flame retardant, which is increasingly reported in the environment. A new isotopic dilution LC-MS/MS method was developed to determine three HBCD isomers, α-, β- and γ-HBCD in channel catfish, crayfish, hen eggs and fish feeds in this study, and especially for the first time HBCD isomers composition in crayfish, hen eggs and fish feeds. Soxhlet extractor and GPC cleanup were used, some important steps and crucial parameters were modified and intensified compared with other literatures, and LC and MS/MS conditions were optimized. The limits of quantitation values of 0.01, 0.005 and 0.005 ng g⁻¹ wet weight in channel catfish and crayfish were calculated for three HBCD isomers, respectively; so did 0.1, 0.05 and 0.05 ng g⁻¹ wet weight in eggs and 0.2, 0.1, 0.1 ng g⁻¹ wet weight in fish feeds. Recoveries of α-HBCD, β-HBCD and γ-HBCD were ranged between 75% and 105% for these productions at medium and high-level spiked samples, and between 60% and 85% at low-level spiked samples. The established methods were therefore suitable for the determinations of three HBCD isomers in these productions at trace contamination levels. Moreover, thirty commercial channel catfish, crayfish, hen eggs and fish feeds samples collected from local markets, and thirty home-produced hen eggs from private owners in Hubei province of China, were analyzed to determine whether these productions were contaminated by HBCD. Using the established methods, HBCD emerged in 4 of 30 fish feeds and 3 of 30 home-produced eggs, and in low-ng g⁻¹ wet weight.