enantioselectivity was proven by these authors for the occurrence of o,p
0 -DDD in
fish tissue (Garrison et al. 1997). Extracts from 21 fishes captured from river waters
where the sediment has a history of severe DDT contamination from a long-defunct
pesticide manufacturing plant were analysed by enantioselective cGC and CE,
respectively, for o,p
0 -DDD. The fish species were channel catfish (Ictalurus
punctatus (RAF.)), buffalo (Ictiobus cyprinellus (VAL.)) and largemouth bass
(Micropterus salmoides (NM)). As Garrison et al. used a modified γ-phase as
CSP, they assumed that the (À)-enantiomer eluted first, in line with suggestions
made by earlier investigations (Buser and Müller 1995) who separated these enantiomers on a γ-cyclodextrin-based HPLC column. Among the 21 samples, only two
showed positive ER values (both values were 1.10). The range of ratios of the
19 samples with a negative ER was 0.25 to 0.98, but 14 of these fell between 0.40
and 0.79. Apparently, the biological uptake mechanism or some membrane transport
process, or both, favoured the (À)-enantiomer, or else the (+)-enantiomer was
metabolised faster by the fish. However, there was no correlation between fish
species and direction or degree of enantioselectivity. Basically, it cannot be excluded
that the o,p-DDD was partially degraded by an enantioselective process in the
environment, probably in the sediment. Garrison and co-workers later verified this
hypothesis by additional analyses of all DDT-related derivatives including all major
transformation products in fish, water and sediment samples. The here-derived
quantitative results were comprehensively discussed with respect to transformation
and distribution pathways for all target DDT-derivatives at the here-investigated
contaminated location (Garrison et al. 2014). All major transformation products
including DDAs were still found in milligram levels in sediment and water samples.
For the chiral o,p
0 -DDD, enantiomeric fractions (EF) < 0,5 (determined in fish,
sediment and water) were determined confirming similar transformation mainly of
the (+)- enantiomer in all trophic levels of the local food web. Obviously, this EF did
not change significantly over the 15 years since the last survey was conducted
(Garrison et al. 1997).
8.2.1.3 Non-Chlorinated Pesticides
All the organochlorine pesticides were banned in 1970s and 1980s from their
agricultural application due to their considerable hazardous effect (Carson 1964).
New products need to be developed in order to satisfy the growing demand on
agricultural products on a global scale. Many new non-chlorinated pesticides and
other agricultural aids were developed and marketed by the industry for agricultural
use (Phipps et al. 1986; Becker 1997; Wheeler 2002; Lee and Aizawa 2003; Sideris
and Moore 2008; Hester and Harrison 2012).
In 2011, more than 30% of the worldwide used pesticides were chiral organic
chemicals (Garrison et al. 2011a, b). However, only 7% of them are currently
marketed enantiomerically enriched or even in their pure enantiomeric form. In a
comprehensive review, Ulrich et al. reviewed 1693 chiral pesticides currently on the
marked for agricultural applications published as global assessment of the US
Environmental Protection Agency (Ulrich et al. 2012). This number has only
164
8 Enantiomer-Specific Fate and Behaviour of Chiral Contaminants
0 -DDD in
fish tissue (Garrison et al. 1997). Extracts from 21 fishes captured from river waters
where the sediment has a history of severe DDT contamination from a long-defunct
pesticide manufacturing plant were analysed by enantioselective cGC and CE,
respectively, for o,p
0 -DDD. The fish species were channel catfish (Ictalurus
punctatus (RAF.)), buffalo (Ictiobus cyprinellus (VAL.)) and largemouth bass
(Micropterus salmoides (NM)). As Garrison et al. used a modified γ-phase as
CSP, they assumed that the (À)-enantiomer eluted first, in line with suggestions
made by earlier investigations (Buser and Müller 1995) who separated these enantiomers on a γ-cyclodextrin-based HPLC column. Among the 21 samples, only two
showed positive ER values (both values were 1.10). The range of ratios of the
19 samples with a negative ER was 0.25 to 0.98, but 14 of these fell between 0.40
and 0.79. Apparently, the biological uptake mechanism or some membrane transport
process, or both, favoured the (À)-enantiomer, or else the (+)-enantiomer was
metabolised faster by the fish. However, there was no correlation between fish
species and direction or degree of enantioselectivity. Basically, it cannot be excluded
that the o,p-DDD was partially degraded by an enantioselective process in the
environment, probably in the sediment. Garrison and co-workers later verified this
hypothesis by additional analyses of all DDT-related derivatives including all major
transformation products in fish, water and sediment samples. The here-derived
quantitative results were comprehensively discussed with respect to transformation
and distribution pathways for all target DDT-derivatives at the here-investigated
contaminated location (Garrison et al. 2014). All major transformation products
including DDAs were still found in milligram levels in sediment and water samples.
For the chiral o,p
0 -DDD, enantiomeric fractions (EF) < 0,5 (determined in fish,
sediment and water) were determined confirming similar transformation mainly of
the (+)- enantiomer in all trophic levels of the local food web. Obviously, this EF did
not change significantly over the 15 years since the last survey was conducted
(Garrison et al. 1997).
8.2.1.3 Non-Chlorinated Pesticides
All the organochlorine pesticides were banned in 1970s and 1980s from their
agricultural application due to their considerable hazardous effect (Carson 1964).
New products need to be developed in order to satisfy the growing demand on
agricultural products on a global scale. Many new non-chlorinated pesticides and
other agricultural aids were developed and marketed by the industry for agricultural
use (Phipps et al. 1986; Becker 1997; Wheeler 2002; Lee and Aizawa 2003; Sideris
and Moore 2008; Hester and Harrison 2012).
In 2011, more than 30% of the worldwide used pesticides were chiral organic
chemicals (Garrison et al. 2011a, b). However, only 7% of them are currently
marketed enantiomerically enriched or even in their pure enantiomeric form. In a
comprehensive review, Ulrich et al. reviewed 1693 chiral pesticides currently on the
marked for agricultural applications published as global assessment of the US
Environmental Protection Agency (Ulrich et al. 2012). This number has only
164
8 Enantiomer-Specific Fate and Behaviour of Chiral Contaminants