Mixture Of Chemical Substances Research Articles

Endocrine-Disrupting Chemicals in Human Fetal Growth.

Fetal growth is regulated by a complex interaction of maternal, placental, and fetal factors. The effects and outcomes that chemicals, widely distributed in the environment, may have on the health status of both the mother and the fetus are not yet well defined. Mainly mixtures of chemical substances are found in the mothers and placenta. Exposure to endocrine-disrupting chemicals (EDCs) can be associated with fetal growth retardation, thyroid dysfunction, and neurological disorders. EDCs mostly interfere with insulin, glucocorticoid, estrogenic, and thyroid pathways, with subsequent effects on normal endocrine and metabolic functions, which cause changes in the epigenome and state of inflammation with life-long effects and consequences. International scientific societies recommend the implementation of research and of all possible preventive measures. This review briefly summarizes all these aspects.

Occupational Pesticide Exposure, Impaired DNA Repair, and Diseases.

Pesticides are a mixture of chemical substances used to kill pests. Apart from their toxicity to pests, thy affect nontarget organisms. They also generate free radicals producing reactive oxygen species (ROS) which can disturb cellular pathways by inhibiting various enzymes or receptors. Pesticides also induce oxidative DNA damage, DNA adducts, and single or double strand DNA breaks. Various mechanisms of DNA repair deal with such damages and help to maintain cell integrity. Alteration in DNA repair genes modulates the individual's susceptibility towards DNA repair and various diseases. Biological monitoring provides a useful tool for the estimation of genetic risk in populations exposed to pesticides. Large numbers of evidences show that occupational exposure to pesticides in agricultural workers has been associated with an increased incidence of various diseases such as cancer, Parkinson's disease, Alzheimer's disease, reproductive disorders, and birth defects. In this review, we have discussed occupational pesticide exposure, various mechanisms of DNA damage caused by pesticides, DNA repair mechanisms, biomonitoring tools, and various diseases caused by pesticide exposure.

Możliwości zastosowania substancji grzybobójczych z praktyki rolniczej do zwalczania Penicillium chrysogenum jako modelowego rodzaju grzyba bytującego w zbiorach bibliotecznych

Antiseptics are chemical compounds or mixtures of chemical substances that are used for protecting cultivated plants, which also may be used as a new generation biocides in the protection against microorganisms and preservation of library books. The basic component determining the specificity of a plant protection product used for book conservation is the substance biologically active in relation to certain organisms, i.e. which causes the disorder of the physiological processes by blocking the activity of the respective enzymes.The aim of the study was to investigate a group of fungicides, not yet in full use in agricultural practice, in terms of their usefulness in protecting old books. For the investigation triazole derivatives were chosen (as a group of asymmetric fungicides), whose mechanism of biological activity is the inhibition of ergosterol, the substance building blocks of the cell membrane. Before the actual investigation, the biological activity of the fungicides was referred in old books preservation process, involving the appointment of the so-called. ED50 coefficients, i.e. what amount of the substance is needed to destroy half of the pathogen population. The ED50 is used to determine the concentration of working fluid which should be sprayed on the surfaces of the protected material: paper, parchment, leather or fabric, providing the required protective efficacy.

Biological interactions in mixtures of chemical substances

Biological interactions in mixtures of chemical substances

Corrosion-induced release of Cu and Zn into rainwater from brass, bronze and their pure metals. A 2-year field study

A 2-year field study has been conducted in an urban environment to provide annual release rates of copper and zinc from brass (20 wt% Zn) and copper and tin from bronze (6 wt% Sn) compared to sheets of their pure alloy constituents, copper and zinc. Despite relatively low nominal bulk alloy content, substantially more zinc was released from brass compared to copper. Both metals were released at a significantly slower rate from the brass alloy, compared to the pure metals. The proportion of release rates of copper and zinc from the alloy differed significantly from their proportions in the bulk alloy. Bronze showed relatively constant release rates of copper, being similar to that of pure copper sheet. The release of tin from bronze was negligible. The results clearly show that alloys and the pure metals behave very differently when exposed to rainwater. Accordingly, release rates from pure metals cannot be used to predict release rates of individual constituents from their alloys. Generated data are of importance within REACH, the new chemical policy of the European commission, where metal alloys erroneously are being treated as mixtures of chemical substances.

Quality objectives for aquatic life: The problem of mixtures of chemical substances

(1996). Quality objectives for aquatic life: The problem of mixtures of chemical substances. Human and Ecological Risk Assessment: An International Journal: Vol. 2, New developments in modeling wildlife exposure to toxic chemicals, pp. 412-418.

Effect of mixtures of chlorophenols, surfactants, and aniline on growth of Pseudomonas fluorescens

Industrial wastewater often contains a mixture of chemical substances and knowledge of joint action of toxicants is therefore important when the toxicity of an effluent is evaluated or reduction of the toxicity is needed. In this study, the joint action of three pairs of toxicants, selected on the basis of their expected different modes of toxic actions, was tested for inhibition of the growth of the bacteria Pseudomonas fluorescens: pentachlorophenol and aniline, the surfactants nonylphenolethoxylate and tetrapropylenebenzenesulfonate, and pentachlorophenol and 2,4-dichlorophenol. The joint effect of pentachlorophenol and aniline did not differ significantly from additivity, whereas less than additive responses were observed for mixtures of nonylphenolethoxylate and tetrapropylenbenzenesulfonate. A more than additive response was observed for mixtures of pentachlorophenol and 2,4-dichlorophenol at some concentration levels, while at others additive responses were found. It was concluded that joint actions other than additivity may occur between commonly known toxic substances, and that the modes of toxic action of the substances studied can explain the different types of joint action observed in this study. Further, the test strategy followed proved useful in the evaluation of the joint toxicity of binary mixtures.