Results 1 - 10 of 1078
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[en] Leaching of four 14C-labelled pesticides (dieldrin, permethrin, phenyl urea and 4-Cl phenyl urea) were investigated. It was found that dieldrin and permethrin were not leached from soil but adsorbed by the soil; phenyl urea and 4-CL phenyl urea were leached to a 7.5 cm depth
[en] In most instances residues must be determined by chemical or biochemical methods without the use of radioisotopes. These methods assume that the nature of the toxic cpmpounds present is known, and that they can be extracted in known yields. Neither assumption is easily validated except by using radioisotopes. The use of radioisotopes to investigate these problems is described, with examples taken from work on demeton, dieldrin and the fungicide triphenyltin acetate. (author)
[fr]Dans la plupart des cas, les residus doivent etre determines par des methodes chimiques ou biochimiques, sans recourir aux radioisotopes. Ces methodes sont fondees sur l'hypothese que l'on connait la nature des composes toxiques presents et que l'on peut les extraire en quantites connues. Aucune de ces deux conditions n'est facile a realiser si ce n'est a l'aide de radioisotopes. L'auteur decrit l'utilisation des radioisotopes dans l'etude de ces problemes et donne des exemples tires de travaux sur le demeton, la dieldrine et un fongicide (l'acetate de triphenyltine). (author)
[es]En la mayor parte de los casos la determinacion de los residuos de insecticidas debe efectuarse por metodos quimicos o bioquimicos, sin emplear radioisotopos. Para estos metodos se parte de dos supuestos: que se conoce la naturaleza de los compuestos toxicos presentes y que esos pueden extraerse con rendimientos conocidos. Ninguno de estos supuestos puede justificarse facilmente si no es mediante el empleo de radioisotopos. El autor de la memoria examina este empleo de los radioisotopos y cita ejemplos tomados de trabajos efectuados con ios insecticidas Demeton y Dieldrin. y con el fungicida acetato de trifenilestatlo. (author)
[ru]V bol'shinstve sluchaev ostatochnye insektitsidy dolzhny opredelyat'sya khimicheskimi i biokhimicheskimi sposobami bez primeneniya radioizotopov. Pri primenenii ehtikh metodov predpolagaetsya, chto izvesten kharakter prisutstvuyushchikh toksicheskikh smesej i chto oni mogut byt' ehkstragirovany v izvestnykh kolichestvakh. Ni odno predpolozhenie ne mozhet byt' svobodno prinyato, esli ono ne podtverzhdeno radioizotopnoj metodikoj. Opisyvaetsya primenenie radioizotopov dlya issledovaniya ehtikh problem i privodyatsya primery, vzyatye iz rabot, svyazannykh s demetonom, dil'drikom i fungitsidnym trifenilatsetatom olova. (author)
[en] The marine polychaete worm, Nereis virens, is resistant to organochlorine pesticides. When exposed to each of five pesticides (endosulfan, chlordane, endrin, dieldrin, and DDT) in concentrations ranging from 0.03 mg/L (DDT) to 22.0 mg/L (chlordane), only endosulfan and chlordane killed Nereis. In comparison, the same compounds were much more toxic to another marine invertebrate, Crangon septemspinosa. The authors wondered if the resistance of N. virens to organochlorines was related to their response to hypoxia. N. virens is a sediment dweller often found in intertidal regions and consequently may experience periods of severe oxygen deprivation; varying degrees of hypoxia can initiate a switch to anaerobic energy metabolism. When N. virens encounter hypoxic conditions, they can also exhibit a compensatory ventilation response. In the present study, the authors measured the bioaccumulation of endosulfan, dieldrin, and DDT by N. virens under normoxic and hypoxic conditions
[en] The effects of soil amendments on the phytoextraction of ΣDDT (DDT + DDD + DDE) from soil ([ΣDDT] ∼ 1500 ng/g) by a pumpkin variety of Cucurbita pepo ssp pepo were tested and the patterns of ΣDDT storage throughout the plant shoot were examined. The soil amendments did not increase the total amount of ΣDDT extracted into plant shoots, but new information about ΣDDT distribution in the plants was obtained. As observed previously, the ΣDDT concentration in plant leaves (mean 290 ng/g) was significantly lower than in plant stems (mean 2600 ng/g). Further analysis revealed that ΣDDT composition was consistent throughout the plant shoot and that ΣDDT concentration in leaves and stems decreased exponentially as distance from the root increased, which was previously unknown. This new information about the patterns of ΣDDT uptake and translocation within pumpkin plants highlights the need for appropriate plant sampling strategies in future POPs phytoextraction research. - Patterns of ΣDDT storage in a pumpkin plant are elucidated and specific surfactant and mycorrhizal soil amendments did not increase the total amount of ΣDDT phytoextracted into plant shoots.
[en] The effect of fertilizer and sterelization using irradiation were studied on the fate of lindane degradation in two soils under laboratory conditions. Degradation of lindane is higher in organic matter rich soil. Half life of product is respectively about one week and one month for both rich soil and poor soil. Fertilizer used decreases PH of soils and irradiation dose of 1 mrad seems to be insufficient to sterilize completely the soils. Ammonium nitrate stimulates slightly the degradations of lindane in soil (not sterilized) after two months
[en] Existing evidence indicated that dichlorodiphenyltrichloroethane (DDT)-containing antifouling paints were an important source of DDT residues to mariculture zones. However, the magnitude of the impact on aquafarming environment has remained largely unknown. In the present study, the concentrations of DDT and its metabolites (designated as DDXs) were determined in harbor sediment and antifouling paint samples collected from a typical mariculture zone in South China. Compositional and concentration correlation analyses implicated the DDT-containing antifouling paints for fishing boat maintenance as an important source of DDT in the mariculture zone. The annual emission of DDXs to the study region was estimated at 0.58 tons/yr. Furthermore, a comparison of the expected DDT loadings in pelagic fish and field measurements indicated that fish feed especially trash fish was a major source of DDTs in the fish body. Nevertheless, the use of DDT-containing antifouling paints should be limited to prevent further deterioration in aquafarming environment. - Highlights: → Use of antifouling paints in boat maintenance was deemed a main source of DDTs. → The majority of antifouling paint-derived DDTs was sequestered in sediment. → Fish feed has remained the main input source of DDTs in fish body. - The potential impact from the use of DDT-containing antifouling paints on aquafarming environment is examined.