Monitoring dissolved organic carbon in surface and drinking waters

The presence of natural organic matter (NOM) strongly impacts drinking water treatment, water quality, and water behavior during distribution. Dissolved organic carbon (DOC) concentrations were determined daily over a 22 month period in river water before and after conventional drinking water treatment using an on-line total organic carbon (TOC) analyzer. Quantitative and qualitative variations in organic matter were related to precipitation and runoff, seasons and operating conditions. Following a rainfall event, DOC levels could increase by 3.5 fold over baseflow concentrations, while color, UV absorbance values and turbidity increased by a factor of 8, 12 and 300, respectively. Treated water DOC levels were closely related to the source water quality, with an average organic matter removal of 42% after treatment.     

In situ capping design of a pyrite cinder pile in the St. Lawrence river for metal containment

A pile of pyrite cinders discharged from a former manufacturing facility rest upon the bottom of the St. Lawrence River adjacent to Clark Island. In situ capping was the selected remedy to control both the fine particle resuspension that produced a red mud cloud in the water, commonly formed on windy days, and the soluble metals concentrations originating from the pyrite pile. Metal mass balances around the pile allowed estimates of the pre‐capping release rates. Elevated concentrations above the pile were observed for eight metals; these included iron, lead, mercury, selenium, arsenic, copper, cadmium, and zinc. After iron, the highest concentration in the pyrite particles were cadmium and zinc present in the 1,000 mg/kg range. Mercury was the lowest at the 10 mg/kg level in the pyrite solids. For iron the soluble release rate was estimated to be 0.08 g/s, and the particle release was 0.8 to 1.2 g/s. A 30 cm cap consisting of particles 19 to 40 mm in diameter is proposed for the site. Its placement covers a ten‐hectare area and is expected to isolate the fine pyrite particles and prohibit their resuspension into the water column. Design estimates of steady state flux reduction efficiencies range from a low of 99.21 percent for iron to a high of 99.96 percent for copper. Breakthrough times to achieve these steady state flux reductions range from 100 to 3,800 years and metal porewater concentrations at 5 cm below the cap surface are estimated to be reduced by 83 percent. Although soluble metals will continue to be released from the pile zone, the flux of all the metals will be significantly reduced. © 2002 Wiley Periodicals, Inc.     

Prenatal identification of a 45,X/46,Xder(Y) mosaicism and confirmation by high resolution cytogenetics and fluorescence in situ hybridization

A 45,X/46,Xder(Y) mosaicism detected prenatally was shown to have a rare Y inversion- duplication or Y/Y translocation which can only be identified by a combination of high resolution cytogenetics and fluorescence in situ hybridization. The present data indicate the usefulness and importance of chromosome-specific probes in the identification and characterization of chromosome rearrangements.     

Climate change: linking adaptation and mitigation through agroforestry

Agriculture is the human enterprise that is most vulnerable to climate change. Tropical agriculture, particularly subsistence agriculture is particularly vulnerable, as smallholder farmers do not have adequate resources to adapt to climate change. While agroforestry may play a significant role in mitigating the atmospheric accumulation of greenhouse gases (GHG), it also has a role to play in helping smallholder farmers adapt to climate change. In this paper, we examine data on the mitigation potential of agroforestry in the humid and sub-humid tropics. We then present the scientific evidence that leads to the expectation that agroforestry also has an important role in climate change adaptation, particularly for small holder farmers. We conclude with priority research questions that need to be answered concerning the role of agroforestry in both mitigation and adaptation to climate change.     

Prenatal detection of the congenital nephrotic syndrome (Finnish type) by trehalase assay in amniotic fluid

We report relatively high trehalase activity in the amniotic fluid of two fetuses affected with the congenital nephrotic syndrome of the Finnish type. The results suggest that prenatal detection of this condition can be done on this basis in conjunction with the α-fetoprotein and acetylcholinesterase tests in amniotic fluid.     

Bayes methods for combining disease and exposure data in assessing environmental justice

Environmental justice reflects the equitable distribution of the burden of environmental hazards across various sociodemographic groups. The issue is important in environmental regulation, siting of hazardous waste repositories and prioritizing remediation of existing sources of exposure. We propose a statistical framework for assessing environmental justice. The framework includes a quantitative assessment of environmental equity based on the cumulative distribution of exposure within population subgroups linked to disease incidence through a dose-response function. This approach avoids arbitrary binary classifications of individuals solely as 'exposed' or 'unexposed'. We present a Bayesian inferential approach, implemented using Markov chain Monte Carlo methods, that accounts for uncertainty in both exposure and response. We illustrate our method using data on leukaemia deaths and exposure to toxic chemical releases in Allegheny County, Pennsylvania.     

How to negotiate remediation projects with regulatory agencies

The news that a company has been identified as a potentially responsible party (PRP) at a federal or state Superfund site usually sends a current of fear through the company's management. Even executives with experience in Superfund projects foresee a lengthy, complicated process that involves enormous expenditures and a possible public relations disaster. The author argues, however, that the Superfund process can be managed in a cost-effective way, prevent reactive responses, inaction, and ineffective action, and applying the business acumen that enabled the company to prosper in the first place. This article explores a critical aspect of the remediation process—negotiation of settlements with regulatory agencies (EPA or a state department of environmental protection)—and details the practical steps needed to conduct those negotiations. It also describes common mistakes that can be avoided. For brevity and clarity, it is assumed that the company in question is the only PRP that has received a notice letter from the regulatory agency.