EAWAG news 53e (September 2002)
Risk Factors in Water (Entire volume)
Editorial (
en53e_edi_s.pdf,
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Hans-Peter Kohler
Lead Article
Dealing with Risk Factors
(en53e_giger_s.pdf,
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Walter Giger
Modern society has become dependent on a wide range of chemicals; however,
it was not until the second half of the 20th century that we acknowledged
that many of these compounds cause severe environmental and health problems.
An early response was to assess the environmental risk associated with selected
chemicals; depending on the results, various countries subsequently introduced
regulations governing their use. Today, there is a consensus that, at least
in principle, all chemicals that are in use must be evaluated. Unfortunately,
the number of chemicals to be tested is enormous. Therefore, appropriate prioritization
procedures are employed that identify particularly dangerous substances, which
may then be subjected to more extensive risk assessment. In recent years,
an increasing effort has been made to solve chemical pollution problems on
an international level.
Research Reports
The OSPAR Strategy against the Introduction
of Hazardous Substances into the Marine Environment
(en53e_poremski_s.pdf,
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Heinz-Jochen Poremski, Suzanne Wiandt
In 1998, the contracting parties to the OSPAR Convention for the "Protection
of the Marine Environment of the North East Atlantic" agreed on a strategy
to make every effort to cease discharges, emissions and losses of hazardous
substances to the marine environment. Its objective is to prevent pollution
of the maritime area by continuously reducing and eliminating discharges,
emissions and losses of hazardous substances within one generation. The OSPAR
working group DYNAMEC has subsequently developed a transparent and methodically-reliable
procedure for the identification and prioritisation of hazardous substances.
Accordingly, the OSPAR Commission has so far agreed to include 42 hazardous
substances on the OSPAR List of Chemicals for Priority Action.
Sewage Sludge: Fertilizer or Waste?
(en53e_stadelm_s.pdf,
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Franz X. Stadelmann
The use of sewage sludge as an agricultural fertilizer is at the center of
an intense debate. The primary benefit of using sewage sludge as a fertilizer
is the recycling of valuable plant nutrients from the consumer back into the
agricultural system. But this benefit is offset by the risk posed by the introduction
into the environment of potentially harmful chemicals contained in the sewage
sludge. The benefits and the risks must be weighed against one another. In
the short term, we should use only the highest quality sewage sludge; in the
long term, we need to develop systems and techniques that satisfy criteria
for both sustainability (nutrient recycling) and precaution (environmental
protection).
Arsenic in Drinking Water - Vietnam, New
Focus of Attention
(en53e_berg_s.pdf,
screen version 275 KB; en53e_berg_p.pdf,
print version 770 KB)
Michael Berg
In some countries, arsenic is the most important chemical pollutant in ground
water and drinking water. The Bengal Delta region is particularly affected
as 35 million people have been drinking arsenic-rich water for the past 20-30
years, of which one million are currently suffering from chronic arsenic poisoning.
In the Red River Delta around the Vietnamese capital of Hanoi, EAWAG researchers
have recently identified another highly arsenic contaminated groundwater area.
In some locations, the contamination in Vietnam exceeds the standard value
of 10 µg arsenic per liter recommended by the World Health Organization
(WHO) 300 times. Measures to mitigate the arsenic problem include not only
the development of low-cost arsenic detection and easy to use arsenic removal
methods, but also dissemination of information to professionals and consulting
services to public authorities.
Arsenic in Drinking Water - also a Problem
in Switzerland?
(en53e_pfeifer_s.pdf,
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Hans-Rudolf Pfeifer, Jürg
Zobrist
In Switzerland, areas with elevated arsenic levels are found primarily in
the Jura and in the Alps. Weathering and erosion of rocks containing arsenic
releases this element into soils, sediments and natural waters. The national
limit for drinking water of 50 µg/l arsenic is not exceeded anywhere
in Switzerland; however, in localized areas in the Cantons Ticino, Grisons
and Valais, arsenic concentrations in the drinking water are above the level
of 10 µg/l recommended by the World Health Organization (WHO).
Does the Fuel Oxygenate Methyl-tert-butylether
(MTBE) Threaten the Ground Water?
(en53e_schmidt_s.pdf,
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Torsten Schmidt
Methyl-tert-butylether (MTBE) is one of the most important synthetic chemical
compounds world wide. Although simple partition models reveal that MTBE remains
primarily in the atmosphere, there is growing evidence that, similarly to
chlorinated solvents, it may pose a threat to ground water. EAWAG is currently
investigating immission paths and long-term behavior of this quite mobile
and poorly degradable substance.
Antibiotics - The Flipside of the Coin
(en53e_mcardell_s.pdf,
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Christa S. McArdell
Antibiotics that are widely used in human and veterinary medicine are detectable
today in Swiss waste waters and surface waters. Studies performed at EAWAG
show that there are different pathways by which human and veterinary antibiotics
find their way into the aquatic environment: human antibiotics are found in
the effluents of wastewater treatment plants and in lower concentrations in
surface waters; they are not completely removed during the wastewater treatment
process. Veterinary antibiotics, on the other hand, are rarely detected in
the wastewater effluent, but can be found in specific surface waters. They
are carried with animal excreta and liquid manure from the pastures directly
into streams. It is not quite clear yet what effects the antibiotics have
on ecosystems and humans - particularly with respect to the spread of antibiotic
resistance.
How Does the Pill Affect Fish?
(en53e_suter_s.pdf,
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Marc J.-F. Suter
Chemicals with estrogenic effects - so-called environmental hormones - are
believed to be responsible for the promotion of female traits in male fish.
As part of the EU program COMPREHEND, EAWAG has investigated the effects of
wastewater treatment plant effluents on male rainbow trout and found increased
levels of vitellogenin. This egg yolk protein precursor is normally found
in high concentrations in female fish only. Effluent samples from wastewater
treatment plants, which were taken during the fish exposure, underwent chemical
ultra-trace analysis and in vitro testing for estrogenic activity. In some
samples, elevated hormone concentrations could be detected and estrogenic
activity could be confirmed.
Pathogens in (Drinking) Water?
(en53e_koester_s.pdf,
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Wolfgang Köster
Drinking water quality is generally good in most industrialized countries.
Despite this, there have been recurrent "accidents" worldwide over
the last few years, which have often lead to illness patterns of epidemic
proportions. Drinking water quality is routinely monitored for microbial contamination
based on cell counts of so-called "indicator" organisms. Such organisms
include, for example, harmless Enterobacteriaceae, which are part of the normal
flora of the intestinal tracts of humans and other mammals. But for some emerging
pathogens that have shown up more frequently in recent years, the concept
of testing only for conventional indicator organisms is inadequate. Molecular
techniques, based on biochemical, genetic or immunological principles, are
gaining importance. These methods allow selective detection of certain pathogens
and are usually more rapid and more sensitive than traditional methods.
Forum
Challenges in Ecological Risk Assessment
(en53e_forum_s.pdf,
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Joop Hermens
More than 100
000 chemicals have to be evaluated for their risks to human health and the
environment. To achieve this goal, test methods as well as modeling and screening
techniques have to be developed or improved. In addition, there is also an
urgent need for more research concerning the effects of chemicals at the ecosystem
level.
Hannes
Wasmer and his activity at EAWAG
In brief
(en53e_inbrief_s.pdf,
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e_inbrief_p.pdf, print version 570
KB)
Publications and books
Please feel free to submit questions or suggestions any time to the editor Martina Bauchrowitz.