The impact of livestock-farming on welsh streams: the development and testing of a rapid biological method for use in the assessment and control of organic pollution from farms

Organic wastes from intensive agriculture are a major cause of surface-water pollution in Great Britain. There are a large number of possible sources for such pollution, and there is a need to target the efforts of pollution-control authorities to the worst-affected parts of catchments. This paper describes the development of a rapid method for the identification of polluted streams based upon the macro-invertebrate fauna. An indicator key was developed by TWINSPAN classification of data from benthic sampling at 55 sites in West Wales. The key requires assessment of the abundance of four macroinvertebrate taxa and of the extent of 'sewage-fungus' growth, all of which can be determined by examination in the field. The key can separate sites into three groups representing different levels of pollution impact as indicated by differences in biotic indices and chemical data. The system was tested successfully at a further 146 sites in West Wales resulting in the notification of 49 farms to the pollution-control authorities. Non-biologists were able to use the key efficiently after a short period of training. A further test involving 51 sites in Devon indicated that the technique may be adaptable to other parts of Great Britain. It is envisaged that indicator systems designed to suit local fauna may have a major role in a pro-active strategy developed to combat pollution from farms because they have potential advantages over more complex biological methods currently in use.     

Production and transmission of honey bee queen (Apis mellifera L.) mandibular gland pheromone

Summary The social cohesiveness of eusocial insect colonies is maintained primarily through the utilization of pheromones. In this study we quantitatively elucidated the production, secretion, and transmission of 9-keto2(E)-decenoic acid (9-ODA), one of the components of the mandibular gland pheromone of the honey bee queen Apis mellifera; this is the only identified primer pheromone complex in the eusocial insects. Mated queens produce 12–400 g of 9-ODA/day, or between 10% and 170% the average amount found in the glands at any one time. Approximately 0.5 g of 9-ODA is maintained on the body surface of queens by an equilibrium between exudation, internalization, tracking on the comb, and removal by workers. Retinue bees, attending the queen, remove the greatest amount, although the role of the wax as both a sink and a medium for pheromone transfer has been previously underestimated. Only about 1 in 10 retinue workers pick up substantial quantities of pheromone while attending the queen and, within seconds, most of the acquired 9-ODA is found externally on the abdomen, or in the gut. These attendants, also called messenger bees, transfer 9-ODA to other workers, mostly through direct contacts, but also via the wax. A model evaluating the pathways and relative quantities of 9-ODA transferred throughout the nest is presented. As well as being important for a basic understanding of the system, the results have implications for the proper design and use of pheromones in bee management.Offprint requests to: K. Naumann     

DETRITUS ABUNDANCE AND BENTHIC INVERTEBRATE CATCH IN ARTIFICIAL SUBSTRATE SAMPLES FROM MOUNTAIN STREAMS1

ABSTRACT: Artificial substrates were designed using rock filled polyethylene bags which were perforated with holes. The substrates trapped waterborne sediment and detritus which enhanced microhabitat complexity. Colonization was compared in side-by-side tests with multiple plate samplers in mountain streams ranging from second to seventh order. After 41 days the bag samples contained more sediment and detritus and more animals than did multiple plates. Plastic bags exceeded multiple plate samples by a factor of nearly 8 for individuals and 1.5 for taxa expressed as numbers/sampler. Although detritus amounts differed significantly between samplers, catch composition was similar in habitat preference and functional groups. Most taxa were “lotic erosional” or “lotic erosional-depositional” detritivores. The plastic bags better represented the streambed fauna judged by their greater similarity to dip net samples. Bag samplers had 4.5 × the colonization area of multiple plates, hence would be expected to support more species. Catch/m² of colonization area was not significantly different between samplers. Functionally the plastic bags act as detritus retention devices, offering a diverse, highly dynamic microhabitat for colonization. Results are interpretable in terms of research on microdistribution of stream benthos and the river continuum model. This study supports the conclusion that stream benthos abundance and diversity are related to the amount of detritus. Maximum diversity and numbers of individuals occurred in samples from third and fourth order streams. Grazers reached peak abundances in the same streams where the continuum model predicts P>R Shredders reached maximum abundances in third and fourth order streams where the riparian canopy was greatest. Predator abundance changed little with stream size. Although bag samples required more sorting time, the samplers are catch effective, inexpensive, and adaptable.     

Training for jobs

In the past much of the training effort of public agencies was not aimed at specific job vacancies or at areas of skill shortages. In contrast, targeted training aims to provide identified disadvantaged groups with training to enable them to compete for identified job vacancies. This paper looks at the success of targeted training through three examples, at how its effectiveness can be improved, and the role of local government in initiating and developing such training.     

EVALUATION OF ALTERNATIVES TO THE GARRISON DIVERSION UNIT1

ABSTRACT: The Garrison Diversion Unit is a multipurpose water resources project which is currently under development for the purpose of diverting water from the Missouri River basin to irrigate farmland in North Dakota. Due to the objections raised by various interest groups, the project has recently been reviewed by the International Joint Commission. This article surveys the background to the project and the various alternatives that have been proposed. By utilizing recently developed fuzzy set techniques, the proposed alternatives are evaluated and a plausible solution is proposed. The results of the study indicate that it may be advisable to remove the Souris Loop irrigation area from the Garrison project but the environmental impacts of the study may preclude the implementation of any alternative that can affect Canada. These findings are in partial agreement with the recommendations of the International Joint Commission.     

STREAM CHEMISTRY IN THE SOUTHERN BLUE RIDGE: FEASIBILITY OF A REGIONAL SYNOPTIC SAMPLING APPROACH1

ABSTRACT: A pilot study, which was conducted in the Southern Blue Ridge geographical province of the Southeastern U.S., demonstrated the feasibility of a probability-based regional synoptic design for the National Stream Survey, which is a project aimed at estimating the number and percentage of streams in various regions of the U.S. that are acidic or at risk from acid deposition. Estimated population distributions for key chemical variables were not appreciably affected by week-to-week variability in stream chemistry during the spring index period chosen for the study. Differences were observed in estimated acid neutralizing capacity (ANC), nitrate, and pH frequency distributions between spring and summer. Observations made at the downstream node did not represent the chemistry of the entire reach for some variables (ANC and nitrate) as indicated by differences in chemical concentrations between upstream and downstream sampling locations. Coefficients of variation in chemical species were low enough to provide a reasonably stable classification of streams based on ANC. Although median ANC, sulfate, and nitrate concentrations were quite low in the region, the probability of finding streams with ph < 6.3 is less than 1.3 percent at the α= 0.05 confidence level.     

Bioconcentration of nonylphenol in fathead minnows (Pimephales promelas)

Bioconcentration of p-nonylphenol (NP) by fathead minnows was determined under laboratory conditions. Fish were exposed continuously for 42 days to 0.33, 0.93 and 2.36 μgNP/l in a flow-through system. NP was Soxhlet extracted from whole fish homogenates with dichloromethane (DCM). The resulting extract was concentrated and bulk lipids removed by gel permeation and silica-gel chromatography. Compounds were identified and quantified by reverse-phase high-pressure liquid chromatography (RP-HPLC) with fluorescence detection. Mass spectrometry was used for verification of peak assignments. Bioconcentration factors (BCFs) ranged from 245 to 380.     

Perspectives and challenges in the future use of plant nutrients in tilled and mixed agricultural systems

Producing an adequate quantity of healthy food without polluting the environment is a serious challenge for future agriculture around the world. The Food 21 research program in Sweden has researched all aspects--economic, environmental, and social--of sustainable farming systems. This paper presents some of the research from that and other relevant international research programs that have focused on better nutrient-use efficiency, especially for nitrogen and phosphorus. It shows that a range of sustainable solutions to nutrient-use efficiency exists, some of which are complex but some very simple. Government policies, including subsidies; research and technology; and public acceptance of farming practices all combine to create these solutions. Participatory approaches to knowledge transfer are needed, in which scientists, policy makers, farmers, advisers, and consumers exchange information and together build sustainable farming systems.     

The distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans in Jackfish Bay, Lake Superior, in relation to a kraft pulp mill effluent

Samples of whole effluent and effluent suspended solids from a kraft pulp mill and sediments and biota from Jackfish Bay, Lake Superior were analyzed for polychlorinated dibenzo-p-dioxins (CDDs) and dibenzofurans (CDFs). Tetra-CDFs (4CDF) were consistently detected in whole effluent at levels ranging between 0.3 and 1.3 ng/L. Effluent suspended solids also contained 4CDFs as well as traces of 4CDD, 5CDF, 8CDF and 8CDD. The horizontal sediment distribution suggests that the effluent was the only active source of 4CDF in the area but that 8CDD originated from a more general source such as the atmosphere. An abrupt appearance of 4CDF in the more recent sections of a core profile taken in the bay suggests that an operational change at the pulp mill resulted in the formation of 4CDFs in the mill effluent some time after 1973. Moderate values of 4CDF and low values of 4CDD were found in samples of the shrimp confirming the presence of an active source of 4CDF in Jackfish Bay.