The migration and redox transformation processes of toxic Cr(VI) in the upper and deep soil of chromate-polluted site are of great importance for the environmental risk control and soil remediation. In this study, soils from surface to deep (around 30-60 m) and the groundwater in a typical abandoned chromate production plant site which has experienced decades of contamination were both sampled and analyzed. The results show that the soil in the leaching workshop of Cr(VI), dichromate transformation workshop and chromium slag dumping ground exhibits severe contamination of chromium and the pollution has extended to the groundwater, causing serious pollution in groundwater too. The vertical migration and transformation of Cr(VI) in the soil layer are mainly affected by the soil permeability, organic matter content and the amount of water passing through the soil layer. During the downward migration, Cr(VI) tends to be retained by the clay layer and further accumulates around the depth of 5-10 m where the concentrations of both hexavalent and total Cr reach maximum values, and then continues to diffuse from the accumulation layer towards the deeper soil. Accompanying with the reduction of Cr(VI) by organic matter in the soil, the Cr(III) exists at various depths. When the depth is below the groundwater level of saturated aquifer, the distribution of chromium in the soil and groundwater reaches leaching and redox equilibrium due to the long-term interaction between the soil and groundwater.

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BACKGROUND: There is limited research concerning how small companies in particular, respond to health and safety messages.
OBJECTIVE: To understand individuals\' knowledge and beliefs about chemical risks and to compare these with those of experts.
METHODS: The use of chromic acid in particular, and also other chemicals associated with chrome plating were studied. All chromium plating firms were based in the West Midlands. The methodology involved initial face to face interviews (n = 21) with chromium platers, structured questionnaires (n = 84) to test the prevalence of beliefs identified in the interviews, an expert questionnaire, and a workshop to discuss findings. The responses of platers were compared with those of occupational health and safety experts.
RESULTS: Although chromium platers appeared to understand the short term adverse effects of the chemicals to which they are exposed, their understanding of long term, or chronic effects appeared to be incomplete. They had good knowledge of acute effects based primarily on experience. Platers were aware of the hazardous nature of the chemicals with which they work, but did not draw distinction between the terms \"hazards\" and \"risks\". They had difficulties articulating the effects of the chemicals and how exposure might occur; although it is inappropriate to equate this with lack of knowledge. A significant minority of platers displayed deficiencies in understanding key technical terms used in Safety Data Sheets.
CONCLUSIONS: This study provides a method which can be used to gain some understanding of workers\' knowledge and beliefs about risks that they are exposed to in the workplace. The study also identifies gaps between the platers\' knowledge and beliefs and those of experts. New risk information needs to be designed which addresses the information needs of platers using language that they understand.

Synthetic hydrotalcite-like layered materials are known for their ability to remove anions, like the chromates. These sorbents usually exist in powder form, thereby exhibiting high surface area and rapid kinetics for adsorption, but presenting appreciable problems in the subsequent solid/liquid separation process. Almost complete removals were obtained in this paper, from batchwork dispersed-air flotation in presence of a flocculant. Due to the experienced difficulty of flotation of thermally activated (at 500 degrees C) hydrotalcite metal-loaded particles, the application of various surfactants was studied. Continuous-flow laboratory runs certified also the effectiveness of this combined process of sorptive flotation, a promising innovative treatment technology.

Despite its frequent use in industry, acute poisoning by chromic acid has very rarely been reported. We report a patient who developed massive gastrointestinal hemorrhage, acute renal failure, and hepatic injury following chromic acid ingestion, and subsequently died. Postmortem liver and kidney biopsies revealed centrilobular necrosis and severe acute tubular necrosis, respectively.

An interesting case of acute poisoning by chromate compounds is reported. A 51-year-old man committed suicide by ingesting a fatal dose of sodium chromate solution. He unexpectedly lost consciousness 6 h after the ingestion and died approximately 20.5 h later. An examination of the blood showed noticeable hepatic damage and thrombocytopenia. The postmortem examination revealed extensive bleeding in the alimentary tract and a severe hepatic lesion due to hepatocellular necrosis. However, the renal disorder was unusually light in the microscopic and clinical findings. Moreover, the renal lesion was observed mainly in the distal tubules instead of the proximal tubules which is more typical in cases of acute poisonings by diverse heavy metals including chromium. The patient\'s death was assumed to have been caused by circulatory collapse due to internal bleeding and the direct toxicity of chromate compounds with hepatic malfunction and possibly disseminated intravascular coagulation (DIC).

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