Application of the Benthic Ecosystem Quality Index 2 to benthos in Dutch transitional and coastal waters

The Benthic Ecosystem Quality Index 2 (BEQI2) is the Dutch multi-metric index (MMI) for assessing the status and trend of benthic invertebrates in transitional and coastal waters for the Water Framework Directive (WFD). It contains the same indicators, i.e. species richness, Shannon index and AMBI, as in the multivariate m-AMBI. The latter MMI has been adopted by several European countries in the context of WFD implementation. In contrast to m-AMBI, the BEQI2 calculation procedure has been strongly simplified and consists of two steps, i.e. the separate indicator values are normalized using their long-term reference values resulting in three Ecological Quality Ratios (EQRs), which are subsequently averaged to give one BEQI2 value. Using this method only small numbers of samples need to be analysed by Dutch benthos laboratories annually, without the necessity to co-analyse a larger historical dataset. BEQI2 EQR values appeared to correlate quantitatively very well with m-AMBI EQR values. In addition, a data pooling procedure has been added to the BEQI2 tool which enables the pooling of small core samples (0.01–0.025 m²) into larger standardized data pools of 0.1 m² in order to meet the data requirements of the AMBI indicator and to obtain comparable reference values. Furthermore, the BEQI2 tool automatically and efficiently converts species synonym names into standardized species names. The BEQI2 tool has been applied to all Dutch benthos data monitored by Rijkswaterstaat in the period of 1991–2010 in the transitional and coastal waters and salt lakes and these results are reported here for the first time. Reference values for species richness and Shannon index (99 percentile values) and AMBI reference values (1 percentile values) were estimated for all water body–ecotopes and are discussed. BEQI2 results for all these water bodies are discussed in view of natural and human pressures. The pressure sensitivity of the BEQI2 for sewage and dredging/dumping, via the state variables oxygen and suspended matter respectively, was demonstrated

A regional benthic fauna assessment method for the Southern North Sea using Margalef diversity and reference value modelling

The aims of this study are to develop an optimized method for regional benthic fauna assessment of the Southern North Sea which (a) is sensitive and precise (quantified as the slope and the R2 value of the pressure-impact relationships, respectively) for the anthropogenic pressures bottom fishing and organic enrichment, (b) is suitable for estimating and modelling reference values, (c) is transparent, (d) can be efficiently applied using dedicated software; and to apply this method to benthic data from the Southern North Sea. Margalef diversity appeared to be the best performing benthic index regarding these criteria, even better than several Multi-Metric Indices (MMIs) containing e.g. AMBI (AZTI Marine Biotic Index) and ITI (Infaunal Trophic Index). Therefore, this relatively simple and very practical index, including a new reference value estimation and modelling method, and BENMMI software were selected as a common OSPAR (Oslo Paris convention) method for the benthic fauna assessment of the Southern North Sea. This method was applied to benthic fauna data from the Southern North Sea collected during the period 2010–2015. The results in general show lower normalized Margalef values in coastal areas, and higher normalized Margalef values in deeper offshore areas. The following benthic indices were compared in this study: species richness, Margalef diversity, SNA index, Shannon index, PIE index, AMBI, ITI. For each assessment area, the least disturbed benthic dataset was selected as an adjacent 6 year period with, on average, the highest Margalef diversity values. For these datasets, the reference values were primarily set as the 99th percentile values of the respective indices. This procedure results in the highest stable reference values that are not outliers. In addition, a variable percentile method was developed, in which the percentile value is adjusted to the average bottom fishing pressure (according to data from the International Council for the Exploration of the Sea, ICES) in the period 2009–2013. The adjusted percentile values were set by expert judgement, at 75th (low fishing pressure), 95th (medium fishing pressure) and 99th (high fishing pressure) percentile. The estimated reference values for Margalef diversity correlate quite well with the median depth of the assessment areas using a sigmoid model (pseudo-R2 = 0.86). This relationship between depth and Margalef diversity was used to estimate reference values in case an assessment area had insufficient benthic data .For testing the effects of bottom fishing pressure, normalized index values (NIV; index value divided by reference value) were used. The rationale for using NIVs is the assumption that, although a certain level of bottom fishing pressure will have a larger absolute effect on more biodiverse benthic communities in deeper waters than on more robust and less biodiverse coastal benthic communities, the relative effects (tested using NIVs) are comparable. A clear exponentially decreasing relationship (R2 = 0.26–0.27, p 2 cm, respectively) and normalized Margalef diversity values, with an asymptotic normalized Margalef value of 0.45 at a subsurface fishing activity >2.3 sweeps/year. This asymptotic value is predominantly found in coastal waters, and probably shows that the naturally more robust coastal benthic communities have been transformed into resilient benthic communities, which rapidly recover from increasing fishing pressure

Biotransformation and quantitative determination of sulfur-containing metabolites of 1,4-dibromobutane in the rat

Two stable sulfur-containing metabolites were isolated from rat urine following administration of the mutagenic 1,4-dibromobutane. They were identified as tetrahydrothiophene and 3-hydroxysulfolane by gas chromatography and gas chromatography-mass spectrometry and were found to be excreted in 48-hr urine, representing 5.8 +/- 1.1 and 57 +/- 15% of the dose of 1,4-dibromobutane, respectively. When urines of rats treated with 1,4-dibromobutane were collected in a buffer of pH 1.0, however, only 3-hydroxysulfolane was found. It was indirectly shown that an N-acetyl-S-(beta-alanyl)tetrahydrothiophenium salt was present in urine and that this metabolite is probably the precursor of tetrahydrothiophene. The latter product is only formed at higher pH values and quantified after addition of NaOH to buffered urines. Tetrahydrothiophene is probably also formed under physiological conditions in vivo from the N-acetyl-S-(beta-alanyl)-tetrahydrothiophenium salt, but in this case it is subsequently transformed to 3-hydroxysulfolane. Based on these findings, a biotransformation scheme of 1,4-dibromobutane in the rat is proposed. The extensive metabolism via glutathione conjugation resulted in efficient detoxification of 1,4-dibromobutane

Use of semi-permeable membrane devices and solid-phase extraction for the wide-range screening of microcontaminants in surface water by GC-AED/MS

An automated GC-MS-based screening method was developed for over 400 industrial, agrochemical and household chemicals. Extracted ion chromatograms were used and the method was aimed at creating a minimum number of false positives. The compound polarity range usually associated with solid-phase extraction was extended to include very apolar, bioaccumulative, compounds by using the complementary semi-permeable membrane device technique. Real-life samples were taken at four locations in the main Dutch river systems and one in an agricultural area. Some 150 compounds were detected in the low-ng/l to low-g/l range. Next to the target compounds, several brominated and chlorinated non-target compounds were detected by means of GC with atomic emission detection and tentatively identified using mass spectral library searching

Referenties en maatlatten voor natuurlijke watertypen voor de kaderrichtlijn water 2015-2021 ; 2e dr.

In het najaar van 2012 werd een geactualiseerde versie van het document Referenties en maatlatten voor natuurlijke watertypen voor de Kaderrichtlijn Water 2015-2021 vastgesteld. Uit het gebruik van deze maatlatten en het programmeren van de Aquokit Biologie (webservice voor toetsen van ecologische kwaliteit met deze maatlatten ontwikkeld door het InformatieHuis Water) bleek dat er correcties en verduidelijkingen nodig waren om te zorgen voor een juiste en consistente toepassing van de maatlatten. Deze correcties en verduidelijkingen zijn doorgevoerd in deze tweede druk. In bijlage 14 is een overzicht opgenomen van de aanpassingen in de maatlat ten opzichte van de eerst druk