Environmental letters最新文献

The dissolved yellow organic matter is removed from aliquots of the same freshwater sample by four common techniques: lyophilization, ion-exchange, ultrafiltration and organic solvent. Quantitative and qualitative aspects of the recovery, including fractionation by gel filtration and total nitrogen determinations, are presented.

Use of hydrophobic membrane filters is shown to effectively reduce the interfering moisture level in the detection of SO2 in air at the parts per billion range. Quadrol is used as a sensitive coating on piezoelectric crystal detectors in a flow system.

The electroretinogram (ERG) technique was used to measure the visual sensitivity of Caribbean Fruit flies Anastrepha suspensa (Loew), reared at 3 laboratories on 5 artificial diets. These ERGs were compared with those of flies reared from field-infested fruit. Flies reared on artificial diets differed greatly in visual sensitivity, and those reared on fruit were at least 10 times more sensitive than certain strains. Since ERGs can be obtained 3-4 days before the Caribbean fruit fly is sexually mature, the use of visually substandard flies in behavioral studies or field releases could be avoided. The results have stimulated further studies of the effects of nutrition and handling procedures on the vision and behavior of the Caribbean fruit fly in the laboratory and the field. A simple, easy to operate, and inexpensive ERG system is being developed that can be used at any rearing facility to monitor the quality of visual receptors of the insects being produced.

During the non-heating months of June, July and August of 1974, the total and respirable dust content at an underground station of the Newark City Subway System was determined. Higher particulate levels than obtained for ambient Newark air were observed. Additionally, Federal Ambient Primary Air Quality Standards for suspended particulate matter was exceeded in two instances. Qualitative elemental analysis of the particulate matter collected is also reported.

A review is given of different methods of using sex pheromones in pest control programs. Survey and monitoring traps have been used extensively for determining the presence and abundance of pest populations are commercially available. Pheromone trapping studies for insect suppression have shown success with some species and could be a useful tool in some situations. The technique of attracting insects to the host for insect removal or exposure to insecticide has also proved to be useful in some programs. Mating disruption studies using widely-separated pheromone evaporators or encapsulated pheromone distributed throughout an area have indicated a great potential for this technique in insect suppression programs.

Muskelung (Esox-masquinongy chiensis) fry were used in a 96 hour toxicity study with diquat and simazine. Although the death of sufficient control fish invalidated the test as a whole, some interesting observations were made. At the end of 48 hours 4 out of 10 fish had died in the control tank and 8 had died in the simazine tank while all 10 diquat-treated fish appeared healthy. Two model eco-systems with components from Chautauqua Lake, N.Y. were constructed in 20 gallon glass aquaria to trace the movement of 14C labeled diquat. After activity had reached near background levels in the water from the test tank, fish, plants, sediments and snails were counted in a liquid scintillation counter to discover the fate of diquat within the system. The concentration of diquat was found to be highest in sediments, followed by fish tissue, snail parts, with plants having the lowest measured concentration.

The transportation of nuclear materials is on the increase. Although nuclear shipments are only a very small fraction of the Nation's hazardous materials shipments, they attract a great deal of public attention. Shipments of spent nuclear fuel and nuclear wastes are a particular concern. One of the many fears that people have about nuclear energy is the possibility that a nuclear shipment might somehow go awry and cause a serious public hazard. Primarily, they are worried that a shipment of spent reactor fuel or highly radioactive waste could be involved in serious rail or highway accident and dump its contents all over the countryside. Is that really possible? How safe are those shipments? How many are there? What do they look like? Are the packages tested? These and other questions are answered in this paper. Since public risk is the product of the consequences of an accident and its probability, both aspects are presented so that each of us can make up his own mind whether the risk from nuclear shipments is acceptable.