Zearalenone metabolism and excretion in the rat: effect of different doses

Young female rats were orally dosed with either 1 or 100 mg zearalenone kg-1 body weight; zearalenone and metabolites were measured in a 96-h collection of urine and feces by HPLC analysis. Dose had little effect on metabolites formed, or excretion route. In both treatment groups, about 55% of the oral dose was excreted in the feces, while the urine was also a major route of excretion accounting for 15-20% of the administered dose. Zearalenone and metabolites were excreted mainly in the free form, with the production of alpha-zearalenol, the most potent estrogenic metabolite, being greater than 10% of the zearalenone dose.     

Acid mine drainage from inactive eastern coal operations

The most widely used technique for abatement of acid drainage from inactive surface mines and refuse disposal areas is revegetation of a soil cover applied to the waste material. Nonetheless, acid production often persists and in some cases, limits establishment of vegetation. This paper reports on several field studies intended to determine the location of pyrite oxidation zones and migration pathways of oxidation products at inactive spoil and refuse sites.Oxygen required for pyrite oxidation is believed to he provided in the gaseous state from the atmosphere. Therefore, the oxygen concentration in unsaturated mine waste should provide an estimate of the weathering tendency in the local environment. We are currently monitoring gas composition in refuse and spoil at six sites. Barren refuse appeared to be oxygenated (>2% 0₂) in a shallow zone extending less than 1 metre below the surface during most of the year. Preliminary data from coal spoil showed that oxygen can be available throughout the unsaturated thickness, even at a revegetated site. Gas composition varied vertically and laterally at a single site and also appeared to show seasonal dependence.Hydrologic factors are also important in acid production and transport. Discharge monitoring alone does not adequately describe the mass transport of acid products through the spoil. For example, at one reclaimed mine the mean sulfate content in six monitoring wells ranged from 24% to 240% of the mean concentration at the discharge point. Sources of recharge and relative flow rates determine the contribution of a particular zone to overall discharge quality.These basic studies of acid production and transport indicate some shortcomings of standard reclamation practices at certain sites. This information will he used to develop alternative abatement technology designed to mitigate acid production at the source.     

Trace Metals in New England Marine Sediments: Casco Bay, Maine, in relation to Other Sites

The concentrations in surface sediments of the trace metals Cd, Cr, Cu, Ni, Pb and Zn have been determined at 32 stations in the Casco Bay region of the Gulf of Maine. The metals are not distributed homogeneously but exhibit elevated levels around the Portland waterfront and generally low levels at offshore and tidally scoured stations. Comparison of these results to those from both industrialized and non-industrialized sites throughout New England indicates that the sediments in parts of the Casco Bay region are affected by trace metals.     

Factors Affecting the Conservation of Nutrients in Estuarine Waters of the River Tiber

The estuarine processes which can influence the release of nutrients of the River Tiber into the Tyrrhenian Sea have been studied. A conservative behaviour has been found for silicate in different hydrographic conditions.

For nitrogen, positive increments in respect of the dilution values were found in summer, due to regeneration processes; on the contrary a conservative behaviour was observed when seawater did not intrude into the river.

Dissolved phosphorus showed, in all the hydrographic conditions, a positive deviation in respect of the theoretical dilution values. This deviation has been attributed to regeneration processes which take place during the summer period. The chemical release of phosphate from particulate matter is predominant when the saline wedge is absent.     

Variations in Densities of Invertebrate Benthos of the Clyde Estuary Tidal Flats

The Clyde Estuary is recognised as an important area for overwintering flocks of ducks and waders (Smyth et al., 1974. Here we draw attention to some of the spatial and temporal variations in the invertebrate populations on which these birds feed. Smyth et al. (1977) discuss possible relationships between the bird populations and their invertebrate prey. A 12-month survey, 1976-77, provides the main information on numbers of feeding birds (Halliday, 1978), complemented by sampling over the estuarine flats for invertebrate prey species and for chemical environmental factors: salinity, organic carbon, organic nitrogen, dissolved oxygen, as well as sediment grades. Although there is no constant monitoring shceme for the estuarine flats, a series of surveys provide data over the period 1973-1981.     

Carcinogenicity of hexachlorocyclohexane (BHC) in pure inbred swiss mice.

Inbred Swiss mice were treated with technical BHC (1) orally with the diet or by intubation and (2) by skin painting. The total duration of the experiment was 80 weeks. There was no difference in body growth and mortality between the experimental and control groups. Symptoms of intoxication in the form of convulsions and tendency of circling in one direction with drooping ears were observed alongwith corneal opacity 40 weeks after the experiment. Oral BHC treatment resulted in a significant increase in the incidence of liver tumours and tumours of lymphoreticular tissue. Males and females were equally susceptible. Skin painting of mice did not significantly increase the incidence of tumour.     

Mammalian toxicity of Technical X-factor I. An acute oral study

Intragastric administration of acute doses of Technical X-factor (beta-isomer free BHC, a byproduct obtained during separation of Lindane from Tech. BHC) carried in peanut oil elicited typical signs of central nervous system depression in adult rats. The computed oral LD50 values of X-factor were 4174 and 5673 mg/kg. body weight for male and female rats respectively indicating that its acute toxicity was of relatively low order compared to Tech. BHC. It is suggested that the low acute mammalian toxicity of X-factor could possibly be due to a direct antagonism of the delta isomer (present in larger proportion in X-factor) with the gamma isomer.     

Phosphate Analysis of Marine Sediments

Phosphate chemistry at the sediment-water interface could play a key role in the periodic eutrophication events characteristic of a N-W Adriatic coastal area. In order to establish a general knowledge of phosphate speciation in the sediments, we chose the sequential extraction procedure which gave most reproducible results as an analytical method. Comparison of data from the sequential procedure with that obtained with different methods using a single extraction step, indicates some inconsistencies due to the effects of chemical reagents on the sedimentary mineral composition.     

The Contribution by the Study of the Algae Forms (Phytoplankton and Periphyton) as Integrators of Physicochemical and Microbiological Data in the Varenna Stream

Physico-chemical, microbiological, ichthyotoxicological conditions and microalgae of Varenna stream were studied in samples taken in 12 collecting stations. The data reported indicate a marked deterioration proceeding downstream e.g. an increase of bacterial population, concentration of suspended solids, COD and variations in the composition and abundance of phytoplankton and periphyton.