Potential contaminants in rainwater after a bushfire

Transcription

1 Potential contaminants in rainwater after a bushfire Kirstin Ross 1, Harriet Whiley 1, Emmanuel Chubaka 1, Malinda Steenkamp 2, Paul Arbon 2 1. Environmental Health, College of Science and Engineering, Flinders University 2. Torrens Resilience Institute, Flinders University

2 Introduction Roof harvested rainwater is common This rainwater can become contaminated during or after a bushfire Likely contaminants are: PAHs (products of combustion), metals, esp CCA from treated timber, and possibly fire fighting foam/retardant Pinery bushfires: Advice from EHOs based on advice from SA Health was for landholders to drain their tanks Causes additional distress The initial idea was to sample rainwater from bushfire affected areas but no bushfires. So instead:

3 Aims of our project To determine the advice that should be given to landholders about their tank s water after a bushfire To mimic possible rainwater contamination post-bushfire in a laboratory setting To determine whether readily available filtration methods would remove contaminants

4 Methods Burn CCA treated timber to ash

5 Add ash to water, shake, allow to settle for 24 hours dilute 100 ml,10 ml, 1 ml and 0.1 ml in 1 L Measure metals and PAHs before filtering and after filtering

6 Arsenic (mg/l) Chromium (mg/l) Copper (mg/l) Cadmium (mg/l) Lead (mg/l) Manganese (mg/l) Zinc (mg/l) Iron (mg/l) 0.1SS Before filtering (0) (0) <0.001 < (0) <0.005 <0.001 < SS After filtering (0) <0.001 <0.001 < <0.001 <0.005 <0.001 <0.01 1SS Before filtering (0.001) (0.0005) <0.001 < (0) < (0.0005) <0.01 1SS After filtering (0) (0) <0.001 < <0.001 <0.005 <0.001 < SS Before filtering 0.46 (0) (0.005) (0.005) < (0) < (0.0005) (0) 10SS After filtering (0.005) (0.0005) <0.001 < <0.001 <0.005 < (0) 100SS Before filtering 4.6 (0) 1.5 (0) (0) < (0) < (0) (0) 100SS After filtering 3.4 (0) (0.005) <0.001 < <0.001 <0.005 < (0) ADWQ guideline (CrVI) (aesthetic) 0.3 (aesthetic) Spinks, et al not measured Interesting points here: Red = above ADWG 10SS chosen for further experiments as it most closely aligned with Spinks, Phillips et al. (2006) No detectable PAHs

7 Made more ash solution (10SS) Filter through Brita jug filter (150 L) and Puratap under bench filter

8 Arsenic (mg/l) (Drinking water guidelines = 0.01 mg/l) ADWG

9 Chromium (mg/l) (drinking guideline = 0.05 mg/l Cr6+) ADWG (maybe)

10 Zinc (mg/l) (drinking water guideline = 3 mg/l) ADWG

11 Copper (mg/l) (drinking water guideline = 2mg/L) ADWG

12 Filtering: Worked well for some metals Didn t remove others, esp arsenic Would not recommend yet this as a method to purify water Need to test other filters

13 However Arsenic was between 0.25 to 0.46 mg/l Non-potable use guidelines A concentration of total arsenic in drinking water for livestock exceeding 0.5 mg/l may be hazardous to stock health. However, if arsenic is not provided as a food additive and natural levels of arsenic in the diet are low, a level of 5 mg/l in drinking water may be tolerated. (National Health and Medical Research Council (NHMRC), 2008) Short term irrigation water = 2 mg/l (ANZECC and ARMCANZ 2000)

14 However Chromium was between mg/l (maybe) Non-potable use guidelines Long-term trigger value in irrigation water = 0.1 mg/l But: Short-term trigger value in irrigation water (short-term use) = 1.0 mg/l (National Health and Medical Research Council (NHMRC), 2008) Chromium (total Cr) 1.0 mg/l (Cooperative Extension Service University of Kentucky) for agricultural use Hexavalent Cr 0.5 mg/l and trivalent Cr 0.5 mg/l for long term protection (Canadian Council of Ministries of the Environment, 1999)

15 PAHs all below 0.01 µg/l Non potable use guidelines Drinking Water Risk-Based Screening Levels (for LMW PAHs range from mg/l and HMW PAHs mg/l for cattle, sheep, goats, camels, horses (American Petroleum Institute, 2004) Domestic non-potable groundwater use [just benzo(a)pyrene 0.1 µg/l] (LIA, 2010) Fresh water [just naphthalene 16 µg/l] (ANZECC and ARMCANZ, 2000)

16 Contaminant Measured concentration ADWG Cadmium Below PQL (< mg/l) 0.01 mg/l Lead At or near PQL (<0.001) 2 mg/l (health) 1 mg/l (aesthetic) Copper mg/l (1 st expt) 0.83 mg/l (2 nd expt) 0.3 mg/l (aesthetic) Historical components of fire fighting foam Zinc Iron mg/l (1 st expt) mg/l (2 nd expt) mg/l (1 st exp) mg/l (2 nd expt) 3 mg/l (aesthetic) 0.01 mg/l Perfluorohexanesulfonic acid Perfluorooctanesulfonic acid Perfluorooctanoic acid All below PQL (<0.01 µg/l) NA

17 Next: Semi-field validation Rainwater sprayed onto roof Burnoff Ash washed off and collected

18 Polyaromatic Hydrocarbons (PAHs) (products of combustion) Tested for: Naphthalene, Acenaphthylene, Acenaphthene, Fluorene, Phenanthrene, Anthracene, Fluoranthene, Pyrene, Benzo(a)anthracene, Chrysene, Benzo(b,j&k)fluoranthene, Benzo(a)pyrene, Indeno(1,2,3-c,d)pyrene, Dibenzo(a,h)anthracene, Benzo(g,h,i)perylene, And Total +ve PAH's Benzo(a)pyrene TEQ (an estimate of toxicity)

19 PAHs results NaphthalenAcenaphthyAcenaphtheFluorene PhenanthreAnthraceneFluoranthenPyrene Benzo(a)anChrysene Benzo(b,j& Benzo(a)pyIndeno(1,2 Dibenzo(a,hBenzo(g,h,iTotal +ve PBenzo(a)pyrene TEQ µg/l µg/l µg/l µg/l µg/l µg/l µg/l µg/l µg/l µg/l µg/l µg/l µg/l µg/l µg/l µg/l µg/l Org-012 Rainwater <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <2 <1 <1 <1 <1 <1 <5 106 Pre-burnoff sample 1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <2 <1 <1 <1 <1 <1 <5 106 Pre-burnoff sample 2 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <2 <1 <1 <1 <1 <1 <5 92 Post-burnoff sample 1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <2 <1 <1 <1 <1 <1 <5 106 Post-burnoff sample 2 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <2 <1 <1 <1 <1 <1 <5 108 Post-burnoff sample 3 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <2 <1 <1 <1 <1 <1 <5 102 Post-burnoff sample 4 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <2 <1 <1 <1 <1 <1 <5 106

20 Metals Arsenic, Cadmium, Chromium, Copper, Lead, Nickel, Zinc, Mercury Why? Some eucalypts concentrate metals in their leaves Timber (CCA treated)

21 Metals results Arsenic Cadmium Chromium Copper Lead Nickel Zinc Mercury Rainwater <1 0.1 <1 18 <1 < <0.05 Pre-burnoff sample 1a <1 0.2 < < <0.05 Pre-burnoff sample 1b <1 0.2 < < <0.05 Pre-burnoff sample 2 <1 0.1 <1 34 <1 < <0.05 Pre-burnoff sample 3 < <0.05 Pre-burnoff sample 4 < <0.05 Post-burnoff sample 1 < < <0.05 Post-burnoff sample 2 <1 0.1 < <0.05 Post-burnoff sample 3 <1 0.2 <1 30 < <0.05 Post-burnoff sample 4 < < <0.05 ADWG ug/l

22 Conclusions Contaminant concentrations, even in high artificially spiked water samples, are low and acceptable for non-potable uses Provide bottled water Landholders should be encouraged to use their water for recovery purposes Further work needs to be undertaken with other filtration methods to determine whether there is an efficient and affordable way to remove contaminants Field validation next step

23 Next: Field validation We now have baseline data about the water from 60 tanks around SA So: Immediately after a fire collect water and test for PAHs and metals After the first rain collect another sample Compare with baseline data

24 Red Cross Provide the link between us and the homeowners Ask whether home owners are willing for us to take a water sample Ask whether they would like the test results Ensures as little extra stress as possible Ensures appropriate counselling

25 Questions?