PESTICIDE ACCUMULATION IN A NEW IMPOUNDMENT IN IOWA1

ABSTRACT: Estimates were made of the amounts of selected pesticides entering and leaving Saylorville Reservoir, a new partly filled impoundment on the Des Moines River. Samples were collected at 1– or 2-week intervals at stations above, in, and below the reservoir. Atrazine, alachlor, and cyanazine were found only in the dissolved state, and dieldrin and p, p′ -DDE in both the, dissolved and suspended state. Heptachlor epoxide, p,p-DDT. p, p′ -DDD, 2,4-D, 2,4,5-TP, endrin, lindane, methoxychlor, propachlor, and toxaphene were not detected or were at very low concentrations. Estimated deposition in the reservoir from September 1977 to October 1978 was 281 kg atrazine, 251 kg alachlor, 26 kg cyanazine, 16 kg dieldrin, and 20 kg p, p′ -DDE.     

DEEP WELL DISPOSAL OF SECONDARY EFFLUENT IN DADE COUNTY,FLORIDA1

ABSTRACT: Data were obtained from drilling and testing of a test injection well for deep underground injection of waste water effluent from the proposed 50-million-gallon-per-day (mgd) South District Regional Wastewater Treatment Plant of the Miami-Dade Water and Sewer Authority, Dade County, Florida. The drilling operation progressed in stages, each stage coverting the strata to be sealed off by the 48-inch, 40-inch, 30-inch, and 20-inch casings, respectively. Total depth of the well is 3,200 feet. The top of the saline, cavernous, dolomitic Boulder Zone was found at 2,790 feet below the surface and is separated from the Floridan aquifer above by approximately 1,100 feet of confining limestone layers. These confining layers were determined, by packer testing, to be very effective. The transmissivity of the Boulder Zone was estimated to be 14 × 10⁶ gallons per day per foot (gpd/ft) from the data obtained from pump out tests. An 8,000-gallon-per-minute (gpm) injection test was conducted to confirm well performance under operating conditions. Based on all of the data obtained, it was concluded that underground injection into the Boulder Zone of secondary waste water effluent from the proposed treatment plant is feasible, both hydraulically and environmentally. A monitoring system was proposed to provide a record of the effects of injection on the subsurface environment.     

DUAL URBAN AND RURAL HYDROGRAPH SIGNALS IN THREE SMALL WATERSHEDS1

ABSTRACT: Many studies can be found in the literature pertaining to the effects of urbanization on surface runoff in small watersheds and the hydrologic response of undeveloped watersheds. However, an extensive literature review yielded few published studies that illustrate differing hydrologic responses from multiple source areas within a watershed. The concepts discussed here are not new, but the methods used provide a unique, basic procedure for investigating stormwater hydrology in topographically diverse basins. Six storm hydrographs from three small central Pennsylvania watersheds were analyzed for this paper; five are presented. Two important conclusions are deduced from this investigation. First, in all cases we found two distinct peaks in stream discharge, each representing different contributing areas to direct discharge with greatly differing curve numbers and lags representative of urban and rural source regions. Second, the direct discharge represents only a small fraction of the total drainage area with the urban peak becoming increasingly important with respect to the rural peak with the amount of urbanization and as the magnitude of the rain event decreases.     

Efficiency of ASTM Method D4994-89 for Recovery of Enteric Viruses from Biosolids

The ASTM Method D4994-89 has been used in the United States for almost two decades to assess the virological quality of biosolids. However, the efficiency of this method for recovery of different enteric viruses has never been determined. The method was found to recover several different enteroviruses and adenovirus 2 with an efficiency ranging from 18.1 ± 5.5 to 24.6 ± 7.8%.     

Invasion costs,impacts, and human agency: response to Sagoff 2020

Article impact statement: In an era of profound biodiversity crisis, invasion costs, invader impacts, and human agency should not be dismissed.     

Regional electricity transmission planning and SEA: The case of the electricity company ScottishPower

Since 21 July 2004, formal strategic environmental assessment (SEA) requirements are in place for certain plans and programmes in European Union member states. Many public plans and programmes have been identified to fall under these requirements, and there has been a range of research activities particularly in land use and transport planning. However, the way in which SEA is to be applied in the private sector has remained largely unclear. Furthermore, to date there has been comparatively little reported private sector experience and the concrete benefits that SEA may deliver to private companies have not yet been discussed to any large extent. In order to address this shortcoming, the paper looks at SEA application in electricity transmission planning, taking the specific case of the privatized company ScottishPower as an example. Based on the evidence obtained, it is suggested that a structured SEA process can strengthen the environmental component and improve private sector decision-making processes. Corporate governance can be improved, if SEA is applied in a tiered system, addressing different issues and tasks at distinct stages in a clearly defined decision making hierarchy.     

Application of Biobarriers for Groundwater Containment at Fractured Bedrock Sites

Biological barriers are a beneficial application of biofilms that aim at reducing the hydraulic conductivity (K) in geological formations. Several studies have shown the potential benefits of creating such barriers either by stimulating the indigenous microbial community (biostimulation) or injecting bacteria (bioaugmentation). For example, laboratory experiments show that groundwater microorganisms attached to a ceramic surface and generated a biofilm as thick as 1,100 μm. In a limestone fracture, this bacterial community clogged a single fracture up to 99.2 percent within 22 days. At the field scale, applications in porous aquifers led to a five‐fold decrease in K after 2.5 days of biostimulation, and a bioaugmentation with a starved, adapted bacterial culture decreased K by 99.4 percent. One promising development of the biobarrier concept is a field application at a fractured bedrock site. Using a multidisciplinary approach and focusing on a well‐characterized fracture system, a field trial was undertaken in Southern Ontario to measure the extent of bioclogging and the stability over time. This article focuses on the literature pertinent to the preparation of this field trial and presents the innovative approach selected to monitor the bioclogging in such a challenging environment.