A study of the priority substances of the Water Framework Directive ...

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1 Alachlor
� Alachlor is an herbicide (pesticide), used
against grass weeds and broadleaves.
� No information on use in Norway is available.
� There are no available data on environmental
distribution in Norway.
� The potential for transboundary pollution is
limited due to short life span in air.
� No further screening is considered necessary.
Production and use
Alachlor has not been approved as herbicide in
Norway, and there is no registered import since
1974. Alachlor has been banned in Sweden
since 1978, widely used in the US.
Emissions, discharges,
distribution and hot-spots
There is no available data on environmental distribution
in Norway.
Monitoring
There is no available data on screening or monitoring
in Norway.
Need for further screening and monitoring
There is no recorded use of alachlor in Norway.
In Sweden no concentrations of alachlor above
detection limits were found in fish, sediments or
ground water (IVL Rapport, 2004). There is no
need for further screening or monitoring.
Analysis
The analysis of alachlor is often part of multi
pesticide packages offered by several laboratories.
Methods
The methods are based on direct extraction with
an organic solvent (sediment and biota) or solid
phase extraction (SPE), eventually clean-up with
SPE and separation and quantification with GCbased
methods: GC/MS or GC/ECD, however,
also LC/MS methods can be used.
Synergy with other analyses
Sample extraction and clean-up can be co-ordinated
with the analysis of other pesticides which
can be analysed by GC/MS especially other
amide-type herbicides as for example metolachlor.
A study of the priority substances of the Water Framework Directive
TA-2140/2005
FACTS
Cas no.: 15972-60-8
Synonyms: Acetamide, 2-chloro-N-(2,6-diethylphenyl)n-(methoxymetyl)-
Alanex, Bronco, Cannon, Crop
Star, Lariat, Lasso, and Partner.
Properties: Alachlor is a colourless to yellow crystal
compound
Toxic effects: Slightly toxic. Oral LD50 in rat is
between 930 mg/kg and 1350 mg/kg. Irritates skin.
Alachlor is moderately toxic to fish The LC50 (96-hour)
2.4 mg/l in rainbow trout (Oncorhynchus mykiss)
(EXTOXNET). It is on the EU list of substances with documented
endocrine-disrupting effects.
Log Kow: 3,7
Persistence: Low persistence in soil (8 days) and
water (EXTOXNET), higher in anaerobic water (HSDB).
DT50 water = 200 - 500 d (river water without sediment),
23 -206 d (river water after addition of soil or
sediment)
DT 50 whole system = 18 -37 days (CIRCA).
Water solubility: 18,07 mg/l (25°C)
Molecular formula: C 14 H 20 Cl-NO 2
Metabolites: diethylaniline (urine), 2-chloro-2',6'diethylacetanilide
and 1-chloro-acetyl-2,3-dihydro-7ethylindole
(soil) (HSDB)
Use: Herbicide, annual grass weeds, some
broadleaves for protection of corn, soybeans, and
peanuts, potatoes, sorghum etc. (HSDB).
References
� HSDB, Alachlor
� CIRCA Royal Haskoning fact sheets on production,
use and release of priority substances in
the WFD, Alachlor, Final version 31 January
2003
� IVL Rapport (Naturvårdsverket): Occurrence
of the WFD priority substances in Sweden - a
summary of recent environmental monitoring.
2004-03-29.
� Environmental Review no. 15, 2004: List of
Undesirable Substances 2004, Appendix B -
Substances on the EU list of substances with
documented endocrine-disrupting effects
� EXTOXNET Extension Toxicology Network
Pesticide Information Profiles
Alachlor Oregon State University Revised June
1996