Institutional controls for future land use at active installation restoration program (IRP) sites

One of the strategies now in vogue in hazardous waste cleanup is basing remedial strategies on future land use. The initial thrust of CERCLA for permanent and complete remedies has given way, pushed by concepts like “brownfields” and base closure and reuse, to strategies often based on “institutional controls” that attempt to stabilize future land uses at a site based on residual risk. The heart of this concept is that instead of removing all wastes from a site, some wastes can safely remain so long as in the future the site is not used in such a way that the residual contamination poses an unacceptable risk to human health and the environment. “Institutional controls” is a term for land use management strategies that do not rely on engineering approaches to reduce risk, but rather seek to ensure that the site is not used in an inappropriate way in the future. This article cautions that such a strategy has inherent residual risks that must be understood by those involved in implementing hazardous waste cleanups and those responsible for future uses of contaminated property. Simply put, institutional controls are only as good as the processes that are in place to ensure they are respected in the future. This presents particular problems for active duty installations because most of the protections commonly available to private sector sites are not useful at active installations. This article discusses an initiative by the Air Combat Command to develop a handbook on instituting and maintaining land restrictions. It will also discuss that effort in light of the April 21 EPA Region IV guidance on assuring Land Use Controls at Federal Facilities. This article is based on a paper and presentations given at the 1998 ACC Environmental Training Symposium.     

Transplantation of the Subshrub Lotus scoparius: Testing the Home-Site Advantage Hypothesis

Abstract: The long-term success of restored populations may be jeopardized by the collection locality of transplants if they are ill matched to their new environment. The home-site advantage hypothesis predicts that the relative success of introduced populations will decrease as their genetic and environmental distance to the local native population increases. We evaluated this hypothesis for a geographically variable shrub, Lotus scoparius , in southern Californian coastal sage scrub by planting two common-garden experiments with seedlings from 12 source populations. The common-garden sites differed in environment and were each home to different source populations of the two taxonomic varieties, L. s. var. scoparius or L. s . var. brevialatus . We used allozyme data from each source population to calculate genetic distances between populations, and a combination of climatic data and soil traits to calculate environmental distances. At the more mesic, coastal common garden, cumulative fitness of transplants (survival × flower production) was inversely related to genetic distance between source and resident populations. At the more xeric, inland common garden, cumulative fitness (survival × size) decreased significantly with both genetic and environmental distance after one taxonomic variety was excluded from analyses. Geographic distance was only weakly correlated with genetic distance and had little value in predicting cumulative fitness of transplants. Our data support the home-site advantage hypothesis and the idea that mis-matching source populations of these genetically differentiated seed sources may result in lowered success of restored or constructed populations. The genetic and environmental similarities of source populations should be considered when source materials are chosen for transplantation.     

Topsoil inversion as a restoration measure in sand dunes,early results from a UK field-trial

Over-stabilisation and eutrophication affect many dune systems in north-west Europe. This leads to lower diversity of typical dune species and an accumulation of soil nutrients. Existing management techniques to remove excess nutrients include mowing, with removal of cuttings, and turf stripping. A new restoration technique called topsoil inversion or deep ploughing may also be able to counter some of the negative effects of eutrophication. It simulates the burial of established soils with fresh mineral sand, by inverting the soil profile. A trial was carried out on two small blocks of eutrophic dune grassland in North Wales, UK. Nutrient-rich surface soils were buried beneath mineral sub-sand using a double-bladed plough, designed to plough to depths of up to 100 cm. Results show that the organic soil horizons were buried to a depth of 80 cm, and covered with 40–50 cm of mineral sand. The pH and organic matter of the surface layers became comparable to those of mobile dunes. Fifteen months after ploughing, bare sand cover was still 70–90%, but significant sand loss through wind erosion resulted in a thinning of the mineral sand over-burden, leaving the buried organic layer closer to the surface. Natural vegetation colonisation was slow, with the first surviving plants observed after 8 months. The majority of species present at 15 months were present before ploughing and had regenerated from rhizomes or root fragments. The effect of excluding disturbance caused by rabbits, people and dogs was assessed within fenced areas. After 11 months, vegetation cover was greater in the fenced areas than in plots exposed to disturbance, therefore disturbance replaced physical conditions as the dominant influence on plant growth and establishment. These early results suggest the trial has been partially successful, but that topsoil inversion could be combined with other methods such as turf stripping or by stabilisation of the ploughed surface by planting with pioneer species, depending on the ultimate restoration goal.     

Transcervical chorionic villus biopsy with a brush

A brush delivered to the biopsy site by a metal introducer and cannula set was tested as an alternative implement for transcervical collection of chorionic villi. This implement was easy to use and readily identified by ultrasound. With only one attempt at sampling, the overall collection rate for 83 patients was 65 per cent. With practice 84 per cent successful collection was achieved. Gestations between 8 and 11 weeks was the best time for collection of chorionic villi. A single sampling can produce adequate material (15 mg wet weight) suitable for diagnostic purposes. No gestation sac was perforated but some slight bleeding followed the procedure. Appreciable success following a single sampling attempt coupled with the low complication rate suggests that this technique may have clinical application and deserves further investigation.     

Elevated biogenic sulphur dioxide concentrations over the North Atlantic

Elevated biogenic SO₂ from the oxidation of dimethylsulphide (DMS) in the marine atmosphere was measured over the North Atlantic Ocean in spring and summer 2003. Stable isotope apportionment was used to distinguish between anthropogenic and biogenic SO₂ in the marine atmosphere south of Greenland. Atmospheric DMS measurements were within range of previous studies. Biogenic SO₂ concentrations were as high as 82 nmol m^?3 (spring geometric mean: 4 nmol m^?3, σ = 17; summer geometric mean 7 nmol m^?3, σ = 19) and are the highest reported values for marine biogenic SO₂ in the literature. Elevated biogenic SO₂ was found in air masses influenced by anthropogenic pollutants during the summer. This indicates that anthropogenic pollutants may affect the fate of oceanic emissions of sulphur compounds in the atmosphere favoring the formation of cloud condensation nuclei.     

Comparison of total mercury and methylmercury cycling at five sites using the small watershed approach

The small watershed approach is well-suited but underutilized in mercury research. We applied the small watershed approach to investigate total mercury (THg) and methylmercury (MeHg) dynamics in streamwater at the five diverse forested headwater catchments of the US Geological Survey Water, Energy, and Biogeochemical Budgets (WEBB) program. At all sites, baseflow THg was generally less than 1ng L(-1) and MeHg was less than 0.2ng L(-1). THg and MeHg concentrations increased with streamflow, so export was primarily episodic. At three sites, THg and MeHg concentration and export were dominated by the particulate fraction in association with POC at high flows, with maximum THg (MeHg) concentrations of 94 (2.56)ng L(-1) at Sleepers River, Vermont; 112 (0.75)ng L(-1) at Rio Icacos, Puerto Rico; and 55 (0.80)ng L(-1) at Panola Mt., Georgia. Filtered (<0.7microm) THg increased more modestly with flow in association with the hydrophobic acid fraction (HPOA) of DOC, with maximum filtered THg concentrations near 5ng L(-1) at both Sleepers and Icacos. At Andrews Creek, Colorado, THg export was also episodic but was dominated by filtered THg, as POC concentrations were low. MeHg typically tracked THg so that each site had a fairly constant MeHg/THg ratio, which ranged from near zero at Andrews to 15% at the low-relief, groundwater-dominated Allequash Creek, Wisconsin. Allequash was the only site with filtered MeHg consistently above detection, and the filtered fraction dominated both THg and MeHg. Relative to inputs in wet deposition, watershed retention of THg (minus any subsequent volatilization) was 96.6% at Allequash, 60% at Sleepers, and 83% at Andrews. Icacos had a net export of THg, possibly due to historic gold mining or frequent disturbance from landslides. Quantification and interpretation of Hg dynamics was facilitated by the small watershed approach with emphasis on event sampling.     

Large‐Scale Fine‐Resolution Hydrological Modeling Using Parameter Regionalization in the Missouri River Basin

This study simulated crop and water yields in the Missouri River Basin (MRB; 1,371,000 km²), one of the largest river basins in the United States, using the Soil and Water Assessment Tool (SWAT) at a fine resolution of 12‐digit Hydrological Unit Codes (HUCs) using the regionalization calibration approach. Very few studies have simulated the entire MRB, and those that have developed were at a coarser resolution of 8‐digit HUCs and were minimally calibrated. The MRB was first divided into three subbasins and was further divided into eleven regions. A “head watershed” was selected in each region and was calibrated for crop and water yields. The parameters from the calibrated head watershed were extrapolated to other subwatersheds in the region to complete comprehensive spatial calibration. The simulated crop yields at the head watersheds were in close agreement with observed crop yields. Spatial validation of the aggregated crop yields resulted in reasonable predictions for all crops except dryland corn in a few regions. Simulated and observed water yields in head watersheds and also in the validation locations were in close agreement in naturalized streams and poor agreement in streams with high groundwater‐surface water interactions and/or reservoirs found upstream of the gauges. Overall, the SWAT model was able to reasonably capture the hydrological and crop growth dynamics occurring in the basin despite some limitations.     

Inhibition of pancreatic carboxypeptidase A: A possible mechanism of interaction between penicillic acid and ochratoxin A

Abstract

Penicillic acid and ochratoxin A are environmentally important toxic fungal metabolites (mycotoxins) that are synergistic in combination. The effects of penicillic acid on the pancreatic enzyme, :arboxypeptidase A were investigated in vitro and in vivo. A broad range of inhibition in vitro of the enzyme by PA was demonstrated with a half‐maximal inhibitory concentration equal to 1.1 x 10^‐4M PA. Inhibition of carboxypeptidase A was time and temperature dependent, and resulted in decreased conversion of parent ochratoxin A to the non‐toxic metabolite, ochratoxin alpha. Studies in vivo demonstrated a penicillic acid‐dependent inhibition of pancreatic carboxypeptidase A activity in the mouse and the chicken following multiple oral exposure. It is postulated that the mode of toxic interaction of the two mycotoxins may be due, in part, to impaired detoxification of ochratoxin A through peni‐cillic acid depletion of carboxypeptidase A activity.     

Evaluation of the RAMS Continuous Monitor for Determination of PM2.5 Mass Including Semi-Volatile Material in Philadelphia,PA

Abstract

The real-time ambient mass sampler (RAMS) is a continuous monitor based on particle concentrator, denuder, drier, and tapered element oscillating microbalance (TEOM) monitor technology. It is designed to measure PM_2.5 mass, including the semi-volatile species NH₄NO₃ and semi-volatile organic material, but not to measure PM_2.5 water content. The performance of the RAMS in an urban environment with high humidity was evaluated during the July 1999 NARSTO-Northeast Oxidant and Particles Study (NEOPS) intensive study at the Baxter water treatment plant in Philadelphia, PA. The results obtained with the RAMS were compared to mass measurements made with a TEOM monitor and to constructed mass obtained with a Particle Concentrator-Brigham Young University Organic Sampling System (PC-BOSS) sampler designed to determine the chemical composition of fine particles, including the semi-volatile species. An average of 28% of the fine particulate material present during the study was semi-volatile organic material lost from a filter during particle collection, and 1% was NH₄NO₃ that was also lost from the particles during sampling. The remaining mass was dominantly nonvolatile (NH₄)₂SO₄ (31%) and organic material (37%), with minor amounts of soot, crustal material, and nonvolatile NH₄NO₃. Comparison of the RAMS and PC-BOSS results indicated that the RAMS correctly monitored for fine particulate mass, including the semi-volatile material. In contrast, the heated filter of the TEOM monitor did not measure the semi-volatile material. The comparison of the RAMS and PC-BOSS data had a precision of ±4.1 μg/m³ (±9.6%). The precision of the RAMS data was limited by the uncertainty in the blank correction for the reversible adsorption of water by the charcoal-impregnated cellulose sorbent filter of the RAMS monitor. The precision of the measurement of fine par-ticulate components by the PC-BOSS was ±6-8%.     

酸化湖泊水生生物恢复的理论框架构建

在欧洲和北美广大地区,随着大气硫沉降的减少,地表水体酸度正在逐渐降低,但是对水质改善的生态响应过程却依然扑朔迷离.有些湖泊和河流的生物正在恢复,有些水体的生物并没有得到恢复.为理解这些生物响应的差异,有利于酸雨问题的有效管理,我们需要对下面2个问题有清晰的认识:①生物群落恢复所必须经历的生态步骤;②倘若恢复受阻,从哪里着手对恢复进程实施干预,如何干预.本文通过构建一套理论框架来回答上述问题.第一层框架是基于生态学考虑而构建的,通过决策树来反映生态恢复进程中必须经历的若干步骤,步骤之间则通过管理工具或对瓶颈的响应来连接.水质不佳,移生生物供给不足以建群,以及群落水平上对恢复动态变化的阻碍等等都可能成为恢复的瓶颈所在.第二层框架则是基于管理层次来构建的,为了克服瓶颈,框架指明从哪里着手对恢复进程实施干预,为建模来进一步将框架具体化,需要做哪些研究.一旦我们可以用模型来预测酸化水体生态恢复的速率和程度,对硫排放减少带来的效益评价就变得简单起来.而这些模型的构建需要充分认识恢复进程中的生态步骤.本文提出的理论框架将有助于我们朝这个目标迈进.