How to protect groundwater organisms to toxic substances? Wilko Verweij (RIVM) Brigitte Blonk (RIVM/UvA) Michiel Kraak (UvA) EU Working Group Groundwater, Luxembourg, 5 October 2015

Contents Groundwater organisms Sensitivity of groundwater organisms to toxic substances Options for protecting groundwater organisms in WFD Conclusions

Groundwater organisms There is more life in groundwater than you can see: viruses fungi bacteria invertebrates Many species known (at least 7000) Invertebrates adapted to special conditions often blind translucent low metabolic rate slow reproduction

Groundwater organisms Distribution of invertebrates in the Netherlands Occur where coarse sediments are found International context: caves! salamanders snails fish

Objectives of Water Framework Directive WFD: no objectives to protect groundwater organisms But recital of Groundwater Directive (2006): Research should be conducted in order to provide better criteria for ensuring groundwater ecosystem quality and protection. Where necessary, the findings obtained should be taken into account when implementing or revising this Directive. Such research, as well as dissemination of knowledge, experience and research findings, needs to be encouraged and funded. We now know: that organisms occur in groundwater Groundwater Directive acknowledges their importance that these organisms are not currently protected by Water Framework Directive (including Groundwater Directive)

How to protect groundwater organisms? Are groundwater organisms equally sensitive to toxic substances as surface water organisms? What we did: retrieve data about toxicitity of substances to surface water organisms collect data for groundwater organisms compare focus on invertebrates Method: Species Sensitivity Distribution

Species Sensitivity Distribution Collect toxicity data for one substance for as many species as possible Then sort Species 1: LC50 = 12 µg/L Species 2: LC50 = 2222 µg/L Species 3: LC50 = 5 µg/L Species 4: LC50 = 144 µg/L Least sensitive organisms Plot toxicity data for surface water organisms together with toxicity data for groundwater organisms in one graph and compare… Most sensitive organisms

Results Literature scan and interviews with experts Toxicity data for groundwater organisms rather scarce Data available for 6 pesticides: 3,4-dichlorophenol, aldicarb, chlorpyrifos, pentachlorophenol, permethrin, thiram 1 other organic compound: toluene 2 nutrients: ammonium, potassium nitrate 6 metal(loid)s: arsenic, cadmium, chromium, copper, lead, zinc 3 inorganic Cl-compounds: chloride, hypochlorite, chlorine So 18 compounds in total: not many, but rather a wide range Only data from acute toxicity tests available

Results For pentachlorophenol, data for one groundwater species were found Five experiments were performed In one experiment, toxicity is below 5% cut-off

Results For ammonium, data for three groundwater species were found For one of them, toxicity is around 5% cut-off

Results For all other 16 substances, no data below 5% cut-off occur Some data points also in high range E.g. zinc: more or less equally distributed

Summary of results + WFD-instrument For the substances for which data are available: Sensitivity of groundwater organisms more or less similar to that of surface water organisms If surface water standards would be applied to groundwater, groundwater organisms are protected from acute effects Threshold values can be key instrument to implement protection of groundwater organisms in WFD

Threshold values: What do WFD/GWD require? Threshold values should be based on human use groundwater dependent ecosystems Only when relevant for the groundwater body So: if groundwater body influences surface water, one should take into account surface water standards Processes like adsorption or dilution may be taken into account  threshold values can be higher than surface water standards

Solution... If: we use surface water standards as groundwater threshold values, even when no groundwater dependent ecosystems are present for a GWB we do not apply adsorption / dilution etc. we can protect groundwater organisms

Conclusions Groundwater organisms are not protected under current EU-legislation There are indications that groundwater invertebrates are equally sensitive to toxicants as surface water organisms, but this is based on limited data Therefore research focusing on other groups of organisms and on chronic effects is needed By applying surface water standards to groundwater (as threshold values), groundwater organisms can be protected, but only fromacute toxicity

From Guidance Document...