1. H.J. De Lange, R.P.A. Van Wijngaarden, G.H.P. Arts
Ecological vulnerability of macroinvertebrates, comparing sensitivity to vulnerability for chlorpyrifos
H.J. De Lange, R.P.A. Van Wijngaarden, G.H.P. Arts
Introduction
The Ecological Vulnerability Analysis [1] uses species traits of wildlife species to estimate likelihood of exposure to a contaminant and potential recovery mechanisms. For the set of wildlife species used in the original analysis toxicity data were not available to include in the analysis. However, for aquatic macroinvertebrates toxicological sensitivity data for chlorpyrifos are available. We therefore compared the sensitivity data [2, 3] to calculated vulnerability scores for a selection of aquatic macroinvertebrates.
Table 1: Traits used, methodology according to [1]
Methodology
For 19 freshwater invertebrate species ecological traits were collected (Table 1). These were available from an Alterra database, added with literature values. Two vulnerabilty scores were calculated:
1) Without toxicity, category A, B and D each weighed 0.333
2) Including toxicity, category A, B, C, and D each weighed 0.25
Results
Comparing vulnerability 1 (without tox) with LC50 there’s no relation (Fig. 1), suggesting that exposure and recovery are independent of toxicological sensitivity. Ablabesmyia is the most vulnerable, and Gammarus the least.
Showing the 4 categories including toxicological sensitivity (Fig. 2) illustrates the differences between species. The two gastropod species are the least vulnerable in this comparison, due to their very low sensitivity. Ablabesmyia is again the most vulnerable species.
Discussion
The methodology applied was identical to [1]. Vulnerability scores without toxicity (Fig. 1) can be directly compared with the wildlife vulnerability scores. Species in the upper left quadrant combine high vulnerability (by exposure and lack of recovery) and high sensitivity.
Including toxicity in the vulnerability score (Fig. 2) gives a potential indication of field effects. This needs further confirmation.
The method can be further improved specificly for aquatic invertebrates by including more aquatic habitat types, and by including traits specifying mode of respiration.
Figure 1: Sensitivity (LC50) versus vulnerability without toxicity.
References
[1] De Lange et al. 2009, ET&C, 28,
[2] Van Wijngaarden et al. 1996, ET&C,15,
[3] Rubach et al. 2011, Arch Env Contam Toxicol, 60,
Figure 2: Vulnerability score including toxicity broken down into the 4 categories
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