In vivo chronic effect of dimethoate and deltamethrin on rabbits

The in vivo effect of dimethoate and deltamethrin on body and organ weights, serum proteins and on plasma acetylcholinesterase (AChE), aromatic esterase and ATPase were examined in growing male rabbits throughout five months period. Both compounds had no significant effect on body weight; however, adrenal, testis & pituitary weights decreased (P less than 0.01); the liver and spleen weights increased (P less than 0.01) in a dose dependent manner. Serum total proteins and globulin decreased (P less than 0.01) in a dose dependent trend, while serum albumin was not greatly affected. AChE activity was increased (P less than 0.01) after 1 month of treatment with the two doses of dimethoate and deltamethrin; thereafter, AChE activity showed 40% inhibition of the control level. The activity of aromatic esterase increased markedly after the first month, then declined gradually until the fifth month. High dose of dimethoate markedly inhibited this enzyme particularly after the 5th month of treatment. Both doses of deltamethrin increased ATPase activity after the first month of treatment, then the ATPase activity was normal. Dimethoate inhibited ATPase particularly at the end of treatment in a dose dependent manner.     

Perspectives of a large scale environmental survey for chlorinated dioiins: water analyses

During 1983 and 1984, The Dow Chemical Company conducted a study to determine the extent of dioxin contamination at its Midland, Michigan plant and the surrounding area. The primary objectives of this study were to identify, rank order, and when possible quantify potential sources of dioxins to the environment and also to determine the extent of contamination in areas affected by the Dow facility. Early in the study, it was estimated that approximately 0.6g/year of 2378-TCDD was being emitted in 2.5 × 10¹⁰L of wastewater effluent. Data will describe observed sources of TCDD (both current and historical), environmental levels, existing water treatment methods, control measures taken, and future improvements on the water system to reduce TCDD in the effluent.     

Buffer zone widths for honeybees from ground and aerial spraying of insecticides

The relative field hazards of insecticides to honeybees have been estimated by considering intrinsic toxicity levels and field application rates. This approach is extended here to a consideration of buffer zones downwind of sprayed areas by estimating the distance at which bees would encounter an LD(50) dose from spray drift. 'LD(50) distances' are determined for both ground and aerial spraying of ground crops in Britain using published data on spray deposition under various weather conditions. For ground spraying at low wind speeds (< or =3 m s(-1)), this zone of risk is up to 5 m for the great majority of compounds. Aerial spraying in unstable atmospheric conditions appears to produce drift deposits of about the same order of magnitude as from ground spraying at wind speeds of about 4 m s(-1), with maximum LD(50) distances of < or =40 m for chlorpyrifos, fenitrothion and triazophos. For aerial spraying in stable atmospheric conditions these distances would be much greater. Pieris brassicae larvae are contrasted with honeybees in their relative sensitivities to insecticides and consequent LD(50) distances.     

Effect of sulfur dioxide and sulfite on photochemical energy storage of isolated chloroplasts--a photoacoustic study

Photoacoustic spectroscopy was used to study the effect of sulfite and SO(2) on isolated corn mesophyll chloroplasts by monitoring the photochemical energy storage. Sulfite incubation of isolated chloroplasts, either in light or in darkness, caused a decrease in photochemical energy storage. The more pronounced decrease in light indicates a light-dependent sulfite inhibitory site(s) in chloroplasts. Also diphenylcarbazide caused a partial recovery of energy storage in sulfite treated chloroplasts indicating a possible site of damage at the water oxidizing system. Although the chloroplast membranes were found to be insensitive to high concentrations of SO(2) for relatively short exposure periods (10 min) in light, exposure of chloroplasts to 28.5 ng cm(-3) SO(2) for 10 min caused a decrease in energy storage. An attempt was made to explain the mechanism of action of sulfite and SO(2) in chloroplasts.     

Butyltins in sediments from Boston Harbor, USA

Sediments from 12 sites in Boston Harbor were assayed for butyltins. The highest levels of tributyltin (TBT) were found at sites where commercial or pleasure boats were moored, where ocean going vessels dock, and at a former shipyard. Little or no TBT was detected at sites which do not have a history of significant boating activity. Dibutyltin and monobutyltin were also detected at most sites, indicating that degradation of TBT occurs at these sites.     

The fate of chlorobenzenes and permethrins during anaerobic sewage sludge digestion

Mixed primary sewage sludge was incubated anaerobically with and without azide addition to prevent biological activity. The behaviour of 1,3-, 1,4- and 1,2-dichlorobenzene, 1,3,5-, 1,2,4- and 1,2,3-trichlorobenzene, 1,2,3,4- and 1,2,4,5-tetrachlorobenzene, hexachlorobenzene, and cis- and trans-permethrin was examined to determine their potential removal during anaerobic digestion. All the chlorobenzenes were removed to varying extents over 32 days of incubation, ranging from 25% removal for 1,3,5-trichlorobenzene to 80% removal for 1,4-dichlorobenzene. Biodegradation may have been responsible for the reductions in 1,3- and 1,4-dichlorobenzene and 1,2,4- and 1,2,3-trichlorobenzene as there was no significant removal of these compounds in azide treated sludge. The removal over 32 days of cis- and transpermethrin was 87% and 96% respectively. These removals were attributed to a chemical or physical process.     

Cadmium in the diet and body tissues of dunlins Calidris alpina, from the Bristol channel, UK

Cadmium levels were determined in sediments, sediment-dwelling invertebrates and in one of their predators, the dunlin, at five sites in the Bristol Channel. The highest sediment cadmium levels were found in the Taff Estuary and at Avonmouth. The highest invertebrate levels were found at Avonmouth and Swansea. In dunlins, the highest cadmium levels were found in the kidneys, followed by the liver, sternum and pectoral muscle. Adult males had higher levels than adult females. Although first year birds of both sexes had low levels, these increased throughout the course of the winter. There was no simple correlation between the amount of cadmium in the sediments, and that in invertebrates or birds, although the levels in both sediments and invertebrates reached a peak in mid-winter. The most contaminated birds were, however, found closest to a known point source of cadmium.     

Effects of bacterial inoculum and moisture adjustment on composting of pig manure

Spent litter (a mixture of partially composted pig manure and sawdust) was taken from pig pens employing the pig-on-litter system with and without the addition of a commercial bacterial product (Odor control (OC)-organic fertilizers (OF)). A duplicate series of windrows was set up with spent litter which contained the bacterial product and a further duplicate series was set up with spent litter which did not contain the bacterial product. All four sets had their initial moisture content adjusted to 60% but one of each duplicate pair had its moisture content adjusted to 60% during the entire period of further composting in windrows. The rate of further (windrow) composting was significantly different in the litter which contained no bacterial product and which only had its moisture content adjusted at the beginning of the experiment. Decomposition was incomplete in this set even after day 91. In the three other sets, the rate of decomposition was faster and the spent litter became stabilised by day 56. This result suggests that if the bacterial product has been added during the initial pig-on-litter composting process, moisture adjustment during further (windrow) composting is not important. Conversely, if moisture was adjusted during further composting, the addition of bacterial product during initial pig-on-litter composting would be of no value. Such a finding is of remarkable significance in the further composting of spent litter since this indicates that the process could be run on a much more economical basis.     

The global re-cycling of persistent organic pollutants is strongly retarded by soils

'Persistent organic pollutants' (POPs) are semi-volatile, mobile in the environment and bioaccumulate. Their toxicity and propensity for long-range atmospheric transport (LRAT) has led to international bans/restrictions on their use/release. LRAT of POPs may occur by a 'single hop' or repeated temperature-driven air-surface exchange. It has been hypothesised that this will result in global fractionation and distillation-with condensation and accumulation in polar regions. Polychlorinated biphenyls (PCBs)--industrial chemicals banned/restricted in the 1970s--provide a classic illustration of POP behaviour. A latitudinally-segmented global PCB inventory has been produced, which shows that approximately 86% of the 1.3 x 10(6) tonnes produced was used in the temperate industrial zone of the northern hemisphere. A global survey of background surface soils gives evidence for 'fractionation' of PCBs. More significantly, however, very little of the total inventory has 'made the journey' via primary emission and/or air-surface exchange and LRAT out of the heavily populated source regions, in the 70 years since PCBs were first produced. Soils generally occlude PCBs, especially soils with dynamic turnover of C/bioturbation/burial mechanisms. This limits the fraction of PCBs available for repeated air-soil exchange. The forested soils of the northern hemisphere, and other C-rich soils, appear to be playing an important role in 'protecting' the Arctic from the advective supply of POPs. Whilst investigations on POPs in remote environments are important, it is imperative that researchers also seek to better understand their release from sources, persistence in source regions, and the significant loss mechanisms/global sinks of these compounds, if they wish to predict future trends.