Wildlife exposure assessment samples

Pharmacologically, carbofuran inhibits cholinesterase, resulting in stimulation of the central, parasympathetic, and somatic motor systems. Sensitive biochemical tests have been developed to measure cholinesterase inhibition in avian and mammalian brain and plasma samples and are useful in the forensic assessment of carbamate exposure in human and wildlife pesticide incidents (Bal-lantyne and Marrs Hunt and Hooper 1993). Acute toxic clinical effects resulting from carbofuran exposure in animals and humans appear to be completely reversible and have been successfully treated with atropine sulfate. However, treatment should occur as soon as possible after exposure because acute carbofuran toxicosis can be fatal younger age groups of various species are more susceptible than adults (Finlayson et al. 1979). Carbofuran labels indicate that application is forbidden to streams, lakes, or ponds. In addition, manufacturers have stated that carbofuran is poisonous if swallowed, inhaled, or absorbed through the skin. Users are cautioned not to breathe carbofuran dust, fumes, or spray mist and treated areas should be avoided for at least 2 days (Anonymous 1971). Three points are emphasized at this juncture. First, some carbofuran degradation... 

Sediments and biota remain priorities for future CP monitoring according to risk assessments. Analysis of dated sediment cores from Europe and from Asia would help assess the current and past deposition in aquatic environments. Temporal trends of CPs in biota need to be studied and there are a number of wildlife and human tissue banks that could supply suitable samples. While there has been much focus on levels in biota in aquatic environments, more work is needed on levels in terrestrial biota to follow up the early work that demonstrated high concentrations in herbivores. This should include more measurements of human tissue samples (blood, mother s milk) given the potential for human exposure via house dust, vegetation, and meat of herbivorous animals. 

Delta aminolevulinic-acid dehydratase (ALAD) is perhaps the most widely studied heme-related enzyme that is altered by metal contamination. ALAD conjugates two aminolevulinic acid molecules critical to heme biosynthesis. The zinc-dependant enzyme is easily inhibited by lead substitution and has been extensively characterized as a sensitive indicator of lead exposure. Blood is the ideal matrix for assessing ALAD activity in wildlife, and sampling is easy and non-lethal. Decreased ALAD activity has been correlated to lead accumulation in a wide variety of birds such as waterfowl, game birds, raptors, and passerines (28, 42, 53, 54, 90-92). 

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