Acute trichloroethylene poisoning by ingestion: clinical and pharmacokinetic aspects

Assessment of potential cardiovascular risk in trichloroethylene exposure by serum methylated arginine levels

Trichloroethylene (TCE) is a widely used solvent in industrial applications and has toxic effects on various systems. Methylated arginine amino acids (eg asymmetric dimethyl arginine (ADMA), symmetric dimethyl arginine (SDMA)) cause the development of cardiovascular disease by inhibiting NO synthesis, which is considered to be heart-protector. The aim of this study is to determine the risk of cardiovascular diseases in TCE exposure by methylated arginine biomarkers. About 98 controls and 100 TCE-exposed male subjects were included in the study. Trichloroacetic acid (urinary metabolite of TCE), arginine, homoarginine, citrulline ADMA, SDMA, and N-monomethyl L-arginine (L-NMMA) levels were found significantly higher than control group (p < 0.001). The strongest correlation was found between ADMA and Trichloroacetic acid (TCA) level (r = 0.453, p < 0.01). Long-term TCE exposure, may be an important risk factor for cardiovascular diseases by increasing methylated arginine levels.

Evaluation of bio-fenton oxidation approach for the remediation of trichloroethylene from aqueous solutions

In the present study, a Bio-Fenton oxidation approach for the removal of trichloroethylene (TCE) was developed through the optimization of enzyme-based hydrogen peroxide (H₂O₂) production from glucose. Glucose oxidase (GOD) was evaluated for the production of H₂O₂ and the optimized parameters were found to be the oxidation of 60 mM glucose by 1 mg mL^-1 of GOD which yielded a conversion of 88.4% of glucose for subsequent utilization in the Bio-Fenton process. The biologically produced H₂O₂ was further used for the removal of TCE from groundwater samples by addition of ferrous ion to the reaction mixture. To determine the efficiency of hydroxyl radicals generated in Fenton reactions to remove TCE in a cost-efficient way, preliminary experiments such as classical Fenton and pseudo Bio-Fenton were carried out in aqueous solutions containing TCE in order to obtain the optimum conditions and then the efficiency of bio-Fenton was tested in groundwater. Based on these results, almost 97% of TCE was removed from aqueous solution within 30 min of classical Fenton under low pH condition (pH 3.0). While performing pseudo bio-Fenton experiments, the optimum conditions were determined to be pH 7.0 and 30 ppm H₂O₂ which yielded 61% removal of TCE in 30 min. Although a comparatively lower removal (30.2%) in groundwater containing TCE was achieved using Bio-Fenton process, it was at a neutral pH. The process was further enhanced by the addition of hydrogen peroxide after 3 h of reaction and a maximum of 48.4% removal of TCE was observed. Thus, this process will help to prevent the scavenging of the unstable H₂O₂ and can be employed in-situ.

Toxic Encephalopathies

Effective brain function is dependent on precise and complex interactions among neurotransmitters, hormones, enzymes, and electrolytes. Many of the chemically complex substances with which we come into contact can disrupt this intricately balanced system. Toxic substances, whether ingested, inhaled, or absorbed through the skin, may cause an encephalopathic state directly by affecting the brain itself or indirectly by compromising the brain's supportive systems. The article focuses on neurotoxins (heavy metals, solvents and vapors, pesticides, and natural neurotoxins) that directly induce an encephalopathic state.

Encephalopathy and cranial nerve palsies caused by intentional trichloroethylene inhalation

This report describes an acute intentional trichloroethylene exposure that developed neurological and cardiovascular toxicity. The patient presented with palsies of the third, fifth, and sixth cranial nerves. Clinical manifestations, laboratory values, and treatment plans are discussed. Emergency physicians should be aware of the complications of trichloroethylene exposure and consider the diagnosis in patients with similar symptoms.

Concentrations of trichloroethylene and its metabolites in blood and urine after acute poisoning by ingestion

A 58-year-old man fell into a trichloroethylene reservoir bath head first, during a maintenance degreasing bath and accidentally ingested the solvent. Although he showed deep coma, chemical burns and pneumonia on admission, these symptoms gradually subsided. The concentrations of trichloroethylene (TRI) and its metabolites, trichloroethanol (TCE) and trichloroacetic acid (TCA) in blood and urine were measured during hospitalization. Eight hours after the accident, the concentrations of TRI and its metabolites in serum were 31.4 micrograms/ml TRI, 16.5 micrograms/ml TCE and 79.5 micrograms/ml TCA. The serum TRI concentration decreased to 4.3 micrograms/ml on the following day. Elimination of TCE and TCA from serum occurred biphasically, the estimated half-lives of each metabolites being about 52.6 and 50.4 h in an initial fast phase and 268.3 and 277.2 h in a subsequent slow phase, respectively. Urinary TRI excretion persisted for the first 2 days. The urinary TCE and TCA excretions were longer than that of TRI with a biphasic decrease and the total amount of TCE excreted during the first 2 days was about two times that of TCA. The half-life of urinary TCE excretion (t1/2 25.7 h) was shorter than that of TCA (t1/2 52.1 h) in the fast phase but did no difference during the slow phase, with each half-time being about 166.3 h. The kinetics of TRI metabolites in blood and urine in this case were in slight agreement with the results following inhalation exposure previously reported in the literature.