Arsenic Risk to Residents – An Understanding for Spring Valley, DC

Steven H. Lamm, MD   Consultants in Epidemiology and Occupational Health, Inc., Washington, DC, Tel: 202-333-2364

Background: Spring Valley in Washington, DC was the site for ordinance development and testing for the US Army before and during World War I.  Subsequently, both American University and a high-end residential area have developed there.  Both arsenic has now been found at levels of 20-400 ppm, and community members are anxious.

Methods and Materials:  A review of the world’s literature on arsenic and adverse human health effects has been undertaken.  The results have been separated out by disease of concern – organ pathology, cancers, and reproductive risk.  Information has been presented with respect to arsenic exposure levels for which adverse effects are known.  These dosages have been compared with estimated exposure levels from the local contamination using standard toxicological data and local data.

Results:  Information to the community has been developed that places potential risk into context.  Variation in risk estimates relate to underlying assumptions rather than to fundamental data.  The major sources of risk presentation to the community came from risk assessments that defaulted to linearity without examining the underlying data and from failure to consider bio-availability as a modifying factor for exposure.

Conclusion:  Community risk analyses are of greater help when they flag the policy assumptions that fail to take knowledge into consideration.  Fuller knowledge provided the community the opportunity to focus remediation and prioritize.

Arsenic: A Potential Toxic Metal In Urban Soils Under High Traffic Pressure

Gebhard B. Luilo, University of Dar es Salaam, C/o Department of Chemistry, PO Box 35061, Dar es Salaam, Tanzania, Tel: +255-744-587546, Fax: +255-22-2410038
Othman C. Othman and Faustin N. Ngassapa, University of Dar es Salaam, Department of Chemistry, PO Box 35061, Dar es Salaam, Tanzania, Tel: +255-22-2410038, Fax: +255-22-2410038

Urban soils are vulnerable to traffic-induced toxic metal pollution particularly lead. However, little attention has been given to arsenic. Reports from ATSDR, 1989 and US-EPA, 2000 pointed out arsenic is present in fossil fuels in trace amounts. Increasing motor traffic in urban areas may be a source of arsenic in cities and along highways. This study, therefore, aimed at determining the levels of arsenic in roadside soils in the Dar es Salaam City. Soil samples were collected at a depth of 0 – 5 cm from the roadside soils at distances of 1, 5, 15, 35, 50, and 150 m from the road edges and control samples were obtained at 1000 m off the highway. Thirty composite soil samples were analyzed for arsenic by AAS (model AAnalyst 300). The results showed that soils were contaminated with arsenic and its levels ranged from 0.03 - 0.65 ppm. The amount of arsenic in the soil decreased exponentially with increasing distance up to 35 m distance from the road edge. Arsenic levels in the soils varied significantly among the study sites (F = 4.140, p = 0.0096). Pearson rank correlation indicated that arsenic in the roadside soils is related to traffic density (r² = 0.4729) and the low correlation value is attributed to of sandy texture of the soils for which arsenic may not be found in large amounts at the surface soils... In conclusion this study is that arsenic, to some extent, owes its source from the passing motor vehicles and therefore we call upon detailed investigation of arsenic pollution of urban environment in high traffic towns and cities.

Arsenic in Soil and CCA Treated Wood by Field Portable X-ray Fluorescence

David Mercuro, Debbie Schatzlein, and Volker Thomsen, NITON LLC, 900 Middlesex Turnpike, Bldg. 8, Billerica, MA 01821, Tel: 800-875-1578, Fax: 978-670-7422

In recent years, issues surrounding the use of chromated copper arsenate (CCA) preservative chemical have increased. There are concerns of possible As leaching into soil both during the lumber’s in-use life and when the wood is eventually disposed of in un-lined landfills.  This leaching could cause an increase of arsenic in topsoil, which would be a major concern to the health of children and adults.  This potential hazard has led treatment manufacturers to voluntarily stop producing CCA as of the end of 2003, and to begin using alternative wood preservatives. 

X-ray Fluorescence (XRF) has been a widely accepted means of analyzing the preservative content of wood by treatment plants for many years.  CCA is the most widely used wood preservative for decks, playgrounds and exterior housing structures and its analysis in wood is straightforward by XRF.  However, data generated has also shown that XRF, and more specifically field-portable XRF (FPXRF), has the ability to analyze low levels (ppm) of arsenic in soil as well.  Therefore FPXRF is the complete package for CCA measurement. It can be used to monitor proper treatment of wood, sort treated and untreated wood at a construction and demolition landfill, and screen for arsenic leaching in soil. 

Removal of Arsenic from Contaminated Water Using Alkali Fly Ash Permeable Reactive Barrier (AFA-PRB) Material

Hossein Rostami, Philadelphia University, Henry Ave. and School House Lane, Philadelphia, PA  19144, Tel: 215-951-2877, Fax: 215-951-6812, Email:  rostamih@philau.edu
William Brendley, Philadelphia University, Email: brendleyw@philau.edu

Over the past 15 years, about one half million sites with potential contamination have been reported to federal or state authorities.  Of these, about 217,000 sites still need remediation  and new contaminated sites continue to appear each year.  The most common type of contaminants are metals, solvents and petroleum products.  Heavy metals are present in two thirds of Department of Defense (DOD) and superfund sites and about 50% of Department of Energy (DOE) and Resource Conservation and Recovery Act (RCRA) sites. 

AFA-PRB material was used to remove arsenic from contamination water.  Fly ash from three different sources were used to produce reactive barrier of different permeability.  AFA-PRB materials with permeability 10^-2 cm/sec to 10^-1 cm/sec were created.  For reactive barrier material, permeability must be rapid in the range of 10^-2 to 10^-1 cm/sec.  AFA - PRB from three ash sources with permeability of approximately 10^-1 were produced and crushed into pelletized form.  Effectiveness of the various barriers were determined by batch and column tests .  Laboratory experiment indicates arsenic ion reduces from 1000 ppm to less than 2 ppm with 7 liters of solution and arsenic in valent from 10 ppm to less than 1 ppm.  Analyses were performed by Atomic adsorption techniques.

Arsenic Speciation in the Tailings Impoundment of a Gold Recovery Plant in Siberia

Olga V. Shuvaeva, Institute of Inorganic Chemistry, RAS, SB, Ac.Lavrentyev, 3, Novosibirsk 630090, Russia 
Elena V. Lazareva United Institute of Geology, Geophysics and Mineralogy, RAS SB, Ac.Koptug, 3,Novosibirsk 630090, Russia

It is known that arsenic is one of the most dangerous elements in terms of its potential impacts to both to human and ecosystem health. The recovery of gold from ores containing arsenopyrite releases significant amounts of arsenic into the environment. The objectives of the present investigation were to:  (1) document the distribution of arsenic in the solid waste-materials of a tailings impoundment; (2) determine the chemical speciation of arsenic in its sediments and waters; and (3) examine the nature of arsenic transformations in the tailings impoundment.

This study focuses on the Komsomolsk tailings impoundment located in the Kemerovo region of southwestern Siberia. The primary sulphide minerals involved in the cyanidation of these particular ores include arsenopyrite, pyrite, pyrrotite and others. Analytical procedures consisted of field experiments, total arsenic determination in waters and sediments and arsenic speciation in surface and pore waters using the combination of microcolumn HPLC with ETA AAS detection. Arsenic speciation in sediment cores was done using the sequential leaching procedure with our own modifications.

There is an arsenic enrichment in the pore waters with respect to the surface waters in the gold recovery tailings dams. During the storage of the waste materials arsenic is redistributed between solid and dissolved phases and arsenic content in pore waters may become very high (about 1700 m g/L).  It has been established that the primary form of arsenic in the sediments is the mineral arsenopyrite. Only a very small amount of arsenic dissolves during ore processing. The arsenic release from the sediment results from a reductive dissolution of the arsenopyrite and Fe oxides. In the surface water, arsenate and arsenite are the main arsenic species (arsenate is dominant), but in the pore waters methylation processes play a significant role. Arsenic transport is accompanied by their transformation into the less toxic compounds (methylated species) co-existing with the most toxic species (arsenite). The main secondary forms of arsenic in the sediments of the impoundment (more than 20% of the total content) are associated with iron hydroxides.

Background Study of Elevated Arsenic in Soil at a Rhode Island Site

Stephen Zemba, Edmund Crouch, and Shailesh Sahay, Cambridge Environmental Inc., 58 Charles Street, Cambridge, MA  02141, Tel: 617-225-0810, Fax: 617-225-0813
Eirlys Vanderhoff and Ambrose Donovan, McPhail Associates, 30 Norfolk Street, Cambridge, MA  02139, Tel: 617-868-1420, Fax: 617-868-1423

Arsenic concentrations in soils at a residential property in Newport, Rhode Island, were found to exceed both statewide background levels and remediation criteria.   Arithmetic mean arsenic concentrations of 12.0 mg/kg and 11.7 mg/kg in site and background soils, respectively, are both about four times greater than a background level of 2.7 mg/kg published by the Rhode Island Department of Environmental Management (DEM).  A risk-based concentration of 0.4 mg/kg of arsenic in soil is necessary to meet the DEM’s incremental cancer risk target of 1x10^-6.  Given the similarity of arsenic concentrations in site and background soils and a lack of evidence of any anthropogenic releases of arsenic to soils, a background study was undertaken to gauge whether concentrations of arsenic at the site are likely due to natural background conditions.  The study implemented the DEM’s “Guidance for Arsenic in Soil,” and was based on measured arsenic concentrations in 20 soil samples from the site and 21 soil samples determined by site investigators to represent background conditions.  The mean arsenic concentrations in both site and background soils were found to be statistically similar, but the distributions of on- and off-site data differed, possibly due to land development patterns.  Specifically, site soils are expected to have been mixed to a greater degree than background soils due to extensive excavation and regrading of the site.  Presentation of the background study will focus on site history, the implementation and implication of DEM’s arsenic policy, the statistical analyses used to compare site and background data, and technical and regulatory conclusions that have been reached based on the site investigation.

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