A global assessment of chromium pollution using sperm whales (Physeter macrocephalus) as an indicator species

Chromium (Cr) is a well-known human carcinogen and a potential reproductive toxicant, but its contribution to ocean pollution is poorly understood. The aim of this study was to provide a global baseline for Cr as a marine pollutant using the sperm whale (Physeter macrocephalus) as an indicator species. Biopsies were collected from free-ranging whales around the globe during the voyage of the research vessel The Odyssey. Total Cr levels were measured in 361 sperm whales collected from 16 regions around the globe detectable levels ranged from 0.9 to 122.6 μg Cr g tissue⁻¹ with a global mean of 8.8 ± 0.9 μg g⁻¹. Two whales had undetectable levels. The highest levels were found in sperm whales sampled in the waters near the Islands of Kiribati in the Pacific (mean = 44.3 ± 14.4) and the Seychelles in the Indian Ocean (mean = 19.5 ± 5.4 μg g⁻¹). The lowest mean levels were found in whales near the Canary Islands (mean = 3.7 ± 0.8 μg g⁻¹) and off of the coast of Sri Lanka (mean = 3.3 ± 0.4 μg g⁻¹). The global mean Cr level in whale skin was 28-times higher than mean Cr skin levels in humans without occupational exposure. The whale levels were more similar to levels only observed previously in human lung tissue from workers who died of Cr-induced lung cancer. We conclude that Cr pollution in the marine environment is significant and that further study is urgently needed.     

Genotoxicity of chromium in vitro on yeast: Interaction with DNA†

The genotoxicity of chromium chloride was investigated in cells of D₇ strain of Saccharomyces cerevisiae harvested either from logarithmic or stationary growth phase.

A weak induction of mifotic gene conversion and point reverse mutation was obtained when the incubations were performed using phosphate buffer. No genetic effect was observed when the incubations were performed using Tris‐HCl buffer.

The experiments with ⁵¹Cr radiotracer demonstrated that Cr³⁺ ion enters the yeast cells and binds to DNA even if the incubation mixture was performed with Tris HCl buffer. This behaviour could be due to the highest concentration of CrCl₃ that cause some damages to cytoplasmatic membrane.     

铬的浸出毒性试验方法研究

以铬为分析指标,探讨了钻井废充泥浆在不同的提取剂、没的提取时间、不同的固液比以及不同的提取方式下铬的浸出毒性大小,提出了适合评价钻井废充泥浆中铬的浸出毒性的试验方法。     

Chromium speciation in river sediment pore water contaminated by tannery effluent

Cr(VI) is far more soluble and toxic than Cr(III). Sediment pore water was investigated in a river adjacent to the property of a large former tannery, into which Cr-contaminated effluent was discharged over a 55-year period, and where extremely high Cr concentrations have been found in the sediments. Dialysis cells, or peepers, were used to generate depth profiles of Cr concentration in sediment pore water. Samples were analyzed for total Cr using inductively coupled plasma-mass spectrometry (ICP-MS) and for Cr species using high performance liquid chromatography (HPLC)-ICP-MS. The results show an absence of Cr(VI) in all samples. Furthermore, incomplete recovery of Cr(VI) added to the samples collected at the locations with highest sediment Cr concentrations indicate strong reducing conditions at those locations, which are not conducive to the presence of Cr(VI).     

Synthesis of hydrogarnet from molten slag and its hydrogen chloride fixation performance at high temperature

Hydrogarnet was synthesized hydrothermally below 200°C using molten slag obtained from municipal solid waste. For comparison, it was also synthesized using pure-phase CaO–Al₂O₃–SiO₂–H₂O, as reported previously. The structural and textural properties of this material were investigated using various analytical and spectroscopic techniques such as X-ray diffraction, X-ray fluorescence spectrometry, atomic absorption spectrometry (AAS), thermogravimetry/differential thermal analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. The Cl⁻ fixation ability of hydrogarnet was investigated in the temperature range 500–800°C in a fixed-bed flow reactor using a HCl concentration (1000 p.p.m.v.) similar to that of incinerator exhaust gas. Under these experimental conditions, the hydrogarnet was capable of reducing the HCl gas level to less than 1 p.p.m.v. Analysis of the spent catalyst revealed that the hydrogarnet was being transformed into wadalite and CaCl₂ at high temperatures. The elution test for chromium ions in hydrogarnet obtained from slag was also used, and it was found that chromium ions were not eluted from hydrogarnet. Received: January 27, 2001 / Accepted: October 11, 2001     

含铬废渣的综合利用

着重介绍了重庆东风化工厂铬渣综合治理的成效。其中包括该厂已成功应用于工业化生产的铬渣作玻璃着色剂，钙镁磷肥助熔剂，炼铁烧结熔剂等利用途径及其还原解毒机理，以及在水泥等建材方面的应用尝试。     

Model reactions of chromium compounds with mammalian and bacterial cells†

Chromate uptake, reduction, cytotoxicity and mutagenicity were studied with human red blood cells, Chinese hamster ovary (CHO) cells and/or Salmonella typhimurium mutant cells. All cell types rapidly took up chromates whereas chromium(III) salts were excluded under the experimental conditions. Red blood cells reduced and accumulated chromium from chromate. At concentrations above 0.1 mM, chromate inactivated the red cell chromate carrier. Chromate above 0.01 mM inhibited CHO cell proliferation irrespective of the cations present. Chromate and two chromium(III) complexes were mutagenic with Salmonella mutants in the Ames’ assay. A model for chromate metabolism and genotoxicity is proposed.     

Removal of hexavalent chromium from water by Z-scheme photocatalysis using TiO2 (rutile) nanorods loaded with Au core–Cu2O shell particles

All-solid-state Z-scheme photocatalysts, containing Cu₂O, TiO₂ (rutile), and Au as the electron mediator, were prepared and applied to the reduction of Cr(VI) in aqueous solutions. The Cu₂O–Au–TiO₂ composites were prepared by loading Au core–Cu₂O shell hemisphere particles on TiO₂ (rutile) nanorods using a two-step photocatalytic deposition process. Under ultraviolet–visible (UV–vis) light illumination, the Cu₂O–Au–TiO₂ composites exhibited higher photocatalytic Cr(VI) reduction activities than those exhibited by single TiO₂ (rutile) and Cu₂O. In this reaction, a precipitate containing Cr, which was considered to be Cr(OH)₃, was deposited site-selectively on the Au core–Cu₂O shell particles of the composites, indicating that the reduction site of the composite was Cu₂O, and the reaction proceeded according to the Z-scheme. The Cu₂O–Au–TiO₂ composites also exhibited photocatalytic activity under visible light illumination. The oxidation state of Cu in the Cu₂O–Au–TiO₂ composite gradually changed from Cu(I) to Cu(II) during the photocatalytic Cr(VI) reduction. However the composite maintained its high photocatalytic performance even after oxidation. The role of Au in the Cu₂O–Au–TiO₂ composite was examined by comparing the properties of the Cu₂O–Au–TiO₂ composite with those of the Cu₂O–TiO₂ composite prepared via direct Cu₂O deposition on TiO₂.     

Biosorption of Cr(VI) using low cost sorbents

Waste products from industrial operations, such as yohimbe bark, grape stalks, cork and olive stones were investigated for the removal of Cr(VI) from aqueous solutions. Equilibrium batch experiments at room temperature were performed. Metal uptake showed a pH-dependent profile and optimum uptake at initial pH between 2.0–3.0. Slight influence of NaCl on metal uptake was observed. The sorption data fitted well to the Langmuir model within the concentration range studied. Grape stalks proved to be the most efficient sorbent followed by yohimbe bark, cork and olive stones. N. Fiol is the recipient of the 2002 ACE Environmental Chemistry Award     

分光光度法测定水样中铬

在ｐＨ４．４ＨＡＣ－ＮａＡｃ缓冲介质及乳化剂ＯＰ存在下，Ｃｒ６＋与二溴羟基苯基荧光酮（ＤＢＨＰＦ）显色反应生成桔红色络合物．该络合物最大吸收位于４８２ｎｍ波长处，表现摩尔吸光系数εｍａｘ＝３．４７×１０４．络合物配位比为Ｃｒ６＋：ＤＢＨＰＦ＝２：３，Ｃｒ６＋在０－１６μｇ／２５ｍＬ范围内遵守比耳定律．方法已用于水样中微量铬的测定，结果满意．