Environmental hazards,neighbourhood quality,and neighbourhood environmental activism

summary This article presents a study of the association of perceived neighbourhood hazards, neighbourhood quality, and resident behavioural responses in two New Jersey, USA, communities that contain multiple technological hazards and populations that are relatively poor and racially homogeneous. The number of neighbourhood problems was highest among residents who engaged in activities to protect their neighbourhood and perceived that their neighbourhood was of poor or fair quality. These respondents perceived three to five times as many hazards as their counterparts who were passive and perceived that their neighbourhood was of excellent or good quality. Respondents' age, education, gender, type of residential unit occupied, and length of residence in the neighbourhood, were not associated with their evaluation of neighbourhood hazards. The authors argue that multiple-hazard neighbourhoods are excellent environments to learn about perception of hazards.Professor Michael Greenberg is Head of the Department of Urban Studies and Community Health where Professor Dona Schneider and Jim Parry are associates.     

PLANNING DIFFUSE POLLUTION CONTROL: AN ANALYTICAL FRAMEWORK1

ABSTRACT: Determination of an optimal nonpoint pollution control strategy demands information relating to (1) costs of pollutant reduction, (2) transport of pollutants, (3) water quality impact of pollutants, and (4) the economic impact of water quality changes. This paper briefly reviews the literature in each of these areas and suggests an analytical framework useful in the development of an optimal nonpoint pollutant control strategy.     

Effect of pore-water velocity on chemical nonequilibrium transport of Cd,Zn, and Pb in alluvial gravel columns

This paper investigates the effects of pore-water velocity on chemical nonequilibrium during transport of Cd, Zn, and Pb through alluvial gravel columns. Three pore-water velocities ranging from 3 to 60 m/day were applied to triplicate columns for each metal. Model results for the symmetric breakthrough curves (BTCs) of tritium (3H2O) data suggest that physical nonequilibrium components were absent in the uniformly packed columns used in these studies. As a result, values of pore-water velocity and dispersion coefficient were estimated from fitting 3H2O BTCs to an equilibrium model. The BTCs of metals display long tailing, indicating presence of chemical nonequilibrium in the system, which was further supported by the decreased metal concentrations during flow interruption. The BTCs of the metals were analysed using a two-site model, and transport parameters were derived using the CXTFIT curve-fitting program. The model results indicate that the partitioning coefficient (beta), forward rate (k1), and backward rate (k2) are positively correlated with pore-water velocity (V); while the retardation factor (R), mass transfer coefficient ((omega), and ratio of k1/k2 are inversely correlated with V. There is no apparent relationship between the fraction of exchange sites at equilibrium (f) and V. The influence of Von k2 is much greater than on R, beta, omega, and k1. A one-order-of-magnitude change in V would cause a two-order-of-magnitude change in k2 while resulting in only a one order-of-magnitude change in R, beta, omega, and k1. The forward rates for the metals are found to be two to three orders-of-magnitude greater than the corresponding backward rate. However, the difference between the two rates reduces with increasing pore-water velocity. Model results also suggest that Cd and Zn behave similarly, while Pb is much more strongly sorbed. At input concentrations of about 4 mg/l and pore-water velocities of 3-60 m/day in the groundwater within alluvial gravel, this study suggests retardation factors of 26-289 for Cd, 24-255 for Zn, and 322-6377 for Pb.     

Rieselfelder

Soils of the large sewage farm area south of Berlin are contaminated with heavy metals such as Cd, Cr, Cu, Hg, Ni, Pb, Zn. Based on earlier studies the total amount and the bioavailable proportions of heavy metals in soil samples were analysed. In some samples very high levels of total heavy metal concentrations were detected. For Pb, Cd, Cu and Hg the maximum values were 1360, 29.7, 817 and 40.8 mg/kg soil dry matter, respectively. The biovailable fractions of heavy metals which were found primarily in the acetate and EDTA fractions and to a lesser degree in the water extract account for about 50 % (Pb, Ni), 70 % (Cd) or 90% (Zn) of their total amount and may therefore pose a considerable environmental risk.     

Evaluation of a gradient sampling design for environmental impact assessment

Before-After Control Impact (BACI) sampling designsare commonly used in environmental impact assessmentand are considered the most effective for detectingchanges due to anthropogenic disturbances. Thesedesigns handle local spatial variability throughrandomized placement of samples into a treatmentstratum and a control stratum. When a contaminantdisperses with distance from a point source it issuggested that a gradient design will be moresensitive to change than randomized placement ofsamples. This requires allocating samples according todistance, rather than by random placement withinrandomly placed blocks. In this paper gradient versusrandom sampling designs were compared using data froman oil field in the North Sea. The gradient samplingdesign was more powerful than a randomized CI sampling design.     

GROUNDWATER MANAGEMENT ON THE TEXAS HIGH PLAINS1

ABSTRACT The effects of major water management practices on the pumping requirement from the Ogallala aquifer are discussed. Demand on the aquifer may be reduced as much as 15 percent by recycling irrigation runoff, 25 percent by recycling irrigation runoff and irrigating with water from playas, and 29 percent by recycling irrigation water in combination with irrigation from playas and artificial recharge of playa water to the aquifer. Other practices that can result in more efficient use of precipitation and groundwater are limited irrigation, land forming, soil profile modification, and improved irrigation systems, thereby reducing the pumping demand on the Ogallala. Additional water supplies can possibly be obtained by water harvesting, weather modification, and water importation. Conclusions reached were that the overdraft on the aquifer can be reduced by the application of sound water management practices on an area-wide basis.     

The effect of repeated vibration signals on worker behavior in established and newly founded colonies of the honey bee, <Emphasis Type="Italic">Apis mellifera</Emphasis>

Communication signals used in animal social interactions are frequently performed repetitively, but the function of this repetition is often not well understood. We examined the effects of signal repetition by investigating the behavior of worker honey bees that received differing numbers of vibration signals in established and newly founded colonies, which could use signal repetition differently to help adjust task allocations to the labor demands associated with the different stages of colony development. In both colony types, more than half of all monitored workers received more than one vibration signal, and approximately 12% received ≥5 signals during a given 20-min observation period. Vibrated recipients exhibited greater activity and task performance than same-age non-vibrated controls at all levels of signal activity. However, vibrated workers showed similar levels of task performance, movement rates, cell inspection rates, and trophallactic exchanges regardless of the number of signals received. Thus, the repeated performance of vibration signals on individual bees did not cause cumulative increases in the activity of certain workers, but rather may have functioned to maintain relatively constant levels of activity and task performance among groups of recipients. The established and newly founded colonies did not differ in the extent to which individual workers received the different numbers of vibration signals or in the levels of activity stimulated by repeated signals. Previous work has suggested that compared to established colonies, newly founded colonies have a greater number of vibrators that perform signals on a greater proportion of the workers they contact. Taken in concert, these results suggest that vibration signal repetition may help to adjust task allocations to the different stages of colony development by helping to maintain similar levels of activity among a greater total number of recipients, rather than by eliciting cumulative effects that cause certain recipients to work harder than others.     

Issues to consider in the derivation of water quality benchmarks for the protection of aquatic life

While water quality benchmarks for the protection of aquatic life have been in use in some jurisdictions for several decades (USA, Canada, several European countries), more and more countries are now setting up their own national water quality benchmark development programs. In doing so, they either adopt an existing method from another jurisdiction, update on an existing approach, or develop their own new derivation method. Each approach has its own advantages and disadvantages, and many issues have to be addressed when setting up a water quality benchmark development program or when deriving a water quality benchmark. Each of these tasks requires a special expertise. They may seem simple, but are complex in their details. The intention of this paper was to provide some guidance for this process of water quality benchmark development on the program level, for the derivation methodology development, and in the actual benchmark derivation step, as well as to point out some issues (notably the inclusion of adapted populations and cryptic species and points to consider in the use of the species sensitivity distribution approach) and future opportunities (an international data repository and international collaboration in water quality benchmark development).