Antisera to 2,4-dichlorophenoxyacetic acid (2,4-D), a widely used herbicide, have been obtained from rabbits following immunization with various 2,4-D-protein conjugates. Employing [125I] 2,4-D-tyramine as the radioligand for the antisera, very poor assay sensitivity was achieved because of a much higher affinity of the antibodies to the tracer. When using [6-3H] 2,4-D(specific radioactivity 465 GBq/mmol) a sensitive and specific radioimmunoassay (RIA) for 2,4-D could be developed, which allows determination directly in water, plasma and urine samples. Levels as low as approximately 100 pg (450 femtomoles) of 2,4-D can be detected. The antiserum is fairly specific for 2,4-D. Other related phenoxycarboxylic acids and dichlorophenol showed a cross-reactivity smaller than 10%. After a single administration of 2,4-D (0.91 mg/100 g body weight, orally) to rats, plasma and urine levels were determined at different times. Results correspond to those found in the literature, thus indicating the utility of the RIA. Further applications and limitations are discussed.
A river intensively used along its entire course for extracting potable water and for discharging domestic and industrial effluents permanently carries a high load of viruses, including hepatitis A and rotaviruses. In the areas supplied with potable water from this river hepatitis A is endemic. The river has been investigated four times at 16 or more sampling points throughout its course in the years 1981, 1982 and 1983. Coincident with the virological investigation, biological, microbiological and chemical examinations were conducted with the same water sample. At some representatively distributed sampling points along the river course, tests for heavy metals (Cd, Ni, Cu, Cr, Pb) and selected chemical compounds were also performed. The virological quality of the river water largely depends on the virus input via domestic sewage. Statistically significant correlations have been found between virus level, pH, NH4+ and NO3−. Amoebae species are likely to counteract viruses. Knowing the dynamics of river water exploitation above the extraction sites, a model for the estimation of virus content in the raw water could be developed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.