R. Klingbeil, 2011: Boron Concentrations in Desalinated Water: A Real Threat? Review of Health Issues, Technical Aspects and International Guidelines

Boron Concentrations in Desalinated Water -
A Real Threat?
Review of Health Issues, Technical Aspects
and International Guidelines
Muscat, Oman
10-12 October 2011
Ralf Klingbeil
Regional Advisor Environment & Water

Outline
• ESCWA and Regional Advisor services
• PAEW request and ToR
• Status quo: Boron in drinking water in Oman
• Health, toxicology: plants and humans
• Boron functions in plants and humans
• Removal by reverse osmosis desalination
• Drinking water guidelines: global and regional
• Conclusions & recommendations
1 February 2012 www.escwa.un.org 2

UN ESCWA
• 14 Member Countries
• Bahrain
• Egypt
• Iraq
• Jordan
• Kuwait
• Lebanon
• Qatar
• Oman
• Palestine
• Saudi Arabia
• Sudan
• Syrian Arab Republic
• United Arab Emirates
• Yemen

Organizational
Chart

Sustainable Development and Productivity
Division and RA Environment & Water
WaterEnergy
Productive
Sectors
§ Energy efficiency
§ Access to modern
energy services
§ Renewable
energies
§ Advanced/cleaner
fossil fuels
§ Rural electrification
§ Sustainable energy
use in transport
§ Integrated water
resource
management
(IWRM)
§ Management of
shared water
resources
§ Improved water
supply and
sanitation
§ Competitiveness
and productivity of
SMEs
§ Environmentally
sound technologies
§ Sustainable
agriculture and
rural development
§ Trade and
environment
Cross-cutting issues:
§ Climate change adaptation and mitigation
§ Sustainable consumption and production
§ Green economy

RA Environment & Water 2009-10
• Modalities
– Policy Advice, Technical
Support and Advocacy
– Training & Capacity
Building
Workshops, Study Tours,
Fellowships
– Regional Knowledge
Networking
Partnerships w Centers of
Excellence
– Field Projects
Pilot projects with seed money
• Total requests 2009-2010:
– Environment: 38
– Water: 60
Status:
End of 2010

RA / TC Example Projects
• Ministry of Economy and Planning (MoEP), Saudi Arabia
– Contribution to “Assessment and Strategic Management of the
Water Sector”, Jul 2009 – Jan 2010
• Ministry of Municipalities Affairs and Urban Planning
(MMAUP), Bahrain
– Contribution to national approach to “Managed Aquifer Recharge
and Reuse of Treated Sewage Effluent”, since Sep 2010
• Public Authority of Electricity and Water (PAEW), Oman
– Various contributions to “Drinking Water Quality Aspects in
Oman”, since May 2009
• Ministry of Water and Irrigation (MWI), Jordan
– Assistance in “Groundwater Monitoring of Disi Transboundary
Aquifer”, in cooperation with BGR, Germany, since Apr 2009

• Assistance in Reviewing
Appropriate Guideline
Values for Boron in
Drinking Water for the
Sultanate of Oman
– Desk Study:
Nov-Dec 2011
– Meeting at PAEW:
22 Dec 2010
– Report presentation:
19 Mar 2011

PAEW Request and ToR
1. Study the impact of boron on consumer health,
2. Review permissible concentrations of boron in
drinking water at the global level and in the
ESCWA region, and
3. Review and discuss appropriate guideline
values for boron in drinking water for Oman.

Boron in Drinking Water
Guideline values:
• Earlier global and current Omani guideline value,
WHO (2008) & MoCI (2006):
– 0.5 mg/l
• New global guideline value,
WHO (2011):
– 2,4 mg/l
• Single stage SWRO membranes can reduce boron
only to about 0.9-1.8 mg/l
• Even two stage RO process often insufficient to
achieve 0.5 mg/l guideline
• Expensive to remove boron to achieve strict
guideline values

Boron in Drinking Water in Oman:
Desalination Product Water

Desalination Product and Feed Water
Region Wilayat Plant
Boron concentration (mg/l)
2007 2008 2009 2010
Product Feed
Al Wusta
Mahout
Hij 1.049 1.632 0.920 1.380
Mahout 1.125 0.973 0.870 0.930
Khaloof 1.754 1.754 1.430
Al Sail Al
Ramla
1.529 1.037 1.170 1.020
Al Nagda 0.330
Al Jazer
Eshairija 0.48 0.601 0.601 1.42
Al Lakbi 1.805 1.957 1.420 1.82 7.25
Kahal 0.187 0.299 0.150 0.65 3.63
Al Daqum
Al Sadanat 0.552 0.758 0.610 1.22 5.43
Ras Al
Madrkah
2.73 1.280 2.09 7.22
Dhahar 0.74 0.843 0.730 0.89 3.54
Hitam 0.42 0.72 0.680 1.21 5.09
Haima Haima 0.600 1.67 6.03
Al Sharqia
Sur
Sur 1.154 1.18 0.420
Tiwi 1.820 1.820
Ras Al Had 1.04 1.032 1.27 1.960
Jalan bani
bu Ali
Asselah 1.12
Ruwais 0.53
Khuwaima 1.275 1.188 1.02 1.28
Al Dakhila Adam
Al zahya 0.725 1.116 1.116 1.300
Adam 0.555 0.704 0.570 0.670
Qarn Al
Alam
1.006 1.342 1.220 1.840

Desalination Product and Feed Water
Region Wilayat Plant
Boron concentration (mg/l)
2007 2008 2009 2010
Product Feed
Muscat
Muscat
Al Ghubrah 0.02 0.01 0.02 0.100
Sifah 1.237 1.306 1.070 1.57 5.02
Khairan 0.273 0.521 0.440 0.62 3.91
Quriyat
Fins 1.169 1.145 0.940 1.19 4.42
Bamah 1.64 0.845 0.720 1.34 5.24
Daghmar 1.550 1.26 4.88
South
Batinah
Barkah
Barkah 1 0.0 0.0 - 0.060
Barkah 2 0.0 0.0 0.770 0.50
Musandam
Khasab
Sheesa 1.228 2.220 2.43
Lima RO
Plant
0.803 0.760 1.02
Lima ED
Plant
0.700 1.05
Daba Diba 0.679 1.550 2.07
Al Dhahirah Ibri
Hamra Al
drua
0.880 0.890
North
Batinah
Sohar Sohar 0.011 0.019 - 0.03

Boron in Drinking Water in Oman
Status in Oman, as of March 2011:
• Desalination product water 2007-2010:
– Only 16% comply with strict 0.5 mg/l guidance
– 84 % are above 0.5 mg/l guideline
– Only 1.8% are above the 2.4 mg/l level
• Product water from RO desalination plants
without any further 2nd pass are often not in
compliance with today’s standards

Natural Occurrence: Boron in Water
• Boron concentration in seawater: 4.5 - 7 mg/l:
– un-dissociated boric acid B(OH)3, pH < 9.2
– ionized borate B(OH)4
-, pH > 9.2
• Found naturally in groundwater
– primarily leaching from rocks and soils
containing borate and borosilicate
• Released through
– weathering processes and
– anthropogenic discharges such as sewage outfalls
• Adsorption-desorption reactions only significant
mechanism influencing boron in water
• Extent of boron adsorption depends on
– pH of water and
– concentration of boron in solution

Health, Toxicology: Plants
• Symptoms: “burned edges” on older leaves,
yellowing of leaf tips, accelerated decay
• Relative tolerance of agricultural crops to boron

Health, Toxicology: Humans
• Symptoms: respiratory irritation, incl.
nosebleeds, eye and nasal irritation, sore
throats, cough, shortness of breath, dermatitis
• Absorption rate of 83-94%, nearly completely
through inhalation and dermal contact
• Lethal doses boric acid:
– oral exposure: 640 mg/kg body weight
– dermal exposure: 8600 mg/kg body weight
– intravenous injection: 29 mg/kg body weight
– 5-20 g for adults
– < 5 g for infants
• No data on carcinogenicity

Accidental intake and poisoning
• Symptoms: gastrointestinal tract disturbances,
vomiting, abdominal pain, diarrhea, nausea,
lethargy, rash, headache, light-headedness,
fever, irritability and muscle cramps
• Intakes in the range of
– 30.4 – 94.7 mg B/kg body weight / day, infants
– twice 45 g intake in 12h interval
• Lethal doses presumably:
– 15-20 g for adults
– 5-6 g for children
– 2-3 g for infants

Boron in drinking water and diets
• Positive correlation betwen boron in drinking
water and blood:
– < 2.5 mg/l boron in drinking water  < 0,1 µg/g blood
– 15.2 mg/l boron in drinking water  0,7 µg/g blood
• No conclusive evidence for impact on fertility or
other reproductive outcomes
• High boron diet (3 mg/day) enhances some
parameters in relation to oestrogen therapy in
post-menopausal women

Boron Functions in Plants and Humans
Plants:
• Essential micronutrient affecting plant growth and development
• In irrigation water / soils important for crop yields and quality of
produce
• Deficiency may exhibit a wide range of symptoms: necrosis,
abnormalities related to the breakdown of internal tissues
Humans:
• Biochemical function of boron remains undefined
• Potential nutritional importance as dynamic trace element affecting
metabolism or utilization of numerous substances in life processes
• Deprivation results in changed biological functions that are
detrimental
• Supplementation may improve osteoarthritis and rheumatoid arthritis
• May reduce risk of inflammatory disease by down-regulating
enzymes of inflammatory response

Boron Removal Processes
Basically three technologies:
• Boron-specific ion exchange resin,
• Strong base anion-exchange resin, and
• Reverse Osmosis (RO):
– Sea Water Reverse Osmosis (SWRO)
• semi-permeable membrane
• most of the dissolved species are rejected
• water permeates it

Boron Removal Processes:
Different RO Processes
• Boron removal process for seawater
desalination, feed conc. 4-5 mg/l, 18-26 °C

Chemistry in Seawater
• Concentration in seawater: 4.8 – 7 mg/l
• Two forms of boron:
– boric acid B(OH)3
– borate B(OH)4
-
• Dissociation constant pKa (boric acid / borate):
f (temperature, pressure, pH, ionic strength)
•
• Removal of non-ionized boric acid by Reverse
Osmosis (RO) is low due to its smaller size and
lack of electric charge

Effect of Different Parameters
Parameter Boron rejection
pH increases Increases
Feed pressure increases Increases
Feed temperature increases Decreases
Feed salinity (ionic strength)
increases
Decreases
Recovery ratio increases Decreases
Mannitol or Fe increases Increases
Feed flow rate increases No effect
Initial boron concentration
increases
No effect

Chemistry in Seawater
• Distribution of boric acid and borate in seawater

Effect of Temperature Change
• Increased temperature results in an reduction in
boron removal
– Total flux through RO membranes incl. salt flux
increases at higher temperature
– Reduction to 70% at 25 °C / 72% at 35 °C

Boron Drinking Water Standards:
Global & Regional
• How to develop a guideline value for boron?
– NOAEL = No Observed Adverse Effects Level:
The adverse effect judged to be most appropriate is the
reproductive toxicity based on Heindel et al., 1992 and
Price et al., 1994.
– Uncertainty Factor:
Based on interspecies and intraspecies factors
– TDI = Tolerable Daily Intake:
Estimate of the intake of a substance that can occur over a
lifetime without appreciable health risks
– Allocation to water:
Percentage of TDI allocated to water intake

Global & Regional
WHO EU AUS CAN USA
Year 2008 2011 1998 Future
2004
2008 2009
AROI
NOAEL (mg/kg/d) 9.6 10.3 - 10.3 9.6 - - 10.3
Uncertainty factor 60 60 - 60 60 - - 66
TDI (mg/kg) 0.16 0.17 - 0.17 0.16 - - 0.2
Allocation to water
(%)
10 40 - 40 10 - - 80
Body weight (kg) 60 60 - 60 70 - - 70
Water
consumption (l/d)
2 2 - 2 2 - - 2
GUIDELINE (mg/l) 0.5 2.4 1 2.4 0.6 4 5 6

Global & Regional
BAH EGY IRQ JOR KUW LEB OMN
Year 1999 2007 2001 2005 1999 1996 2006
Guideline (mg/l) -- 0.5 1.0 2.0 0.5 -- 0.5
oPt SAU SUD SYR UAE YEM
Year 1997 2000 2002 1994 -- --
Guideline (mg/l) -- 0.5 0.2 0.3 -- --
• Global and regional standards vary from 0.2 to 6 mg/l
• Global guidelines derived from formula
• 4 of 13 countries in the region follow 2008 WHO guideline
• No information available on derivation of regional guidelines
nor about their compliance monitoring

Conclusions & Recommendations 1/2
• Oman may wish to review present drinking water
standards with respect to the element of boron
• Change of drinking water guidelines for boron
justifiable
– from 0.5 mg/l to proposed new guidance 2.4 mg/l
• Precautions to be taken for boron > 0.5 mg/l for
plant irrigation
– cost effectiveness of additional boron removal for
local irrigation vs. resettlement of irrigated plantation

Conclusions & Recommendations 2/2
• Major source of boron is seawater (4.5 - 7 mg/l):
– un-dissociated boric acid B(OH)3, pH < 9.2
– ionized borate B(OH)4
-, pH > 9.2
– Small and uncharged boric acid minerals can diffuse through the
RO membrane
– Increasing pH, feed pressure or complexation reactions increase
boron removal rates,
– Increasing temperatures in feed water reduce boron removal
rates
• Current global and regional standards for boron in
drinking water vary from 0.2 mg/l to 6 mg/l
• Insufficient information to prove harmful effects on
human beings
• Expensive boron removal to achieve strict 0.5 mg/l
guideline value

Further Suggestions
• Options for “mobile 2nd pass RO membranes”?
– Feasibility of developing or using mobile / container-
based 2nd pass membranes for boron > 2.4 mg/l
• Accompanying research?
– An increase in guideline values for boron in Oman
could be accompanied with research related to
environmental health with communities largely
depending on boron > 0.5 mg/l
– Joint regional or bilateral research cooperation with
Saudi Arabia, GCC and/or ESCWA countries:
• GCC countries depend largely on desalination for drinking
water
• Boron challenges are largely restricted to RO desalination
mainly used in Oman and Saudi Arabia

Latest Status:
New 2011 WHO Guidance
• WHO, July 2011.
Guidelines for Drinking-Water Quality, 4th ed.
– Boron
Guideline value 2.4 mg/l (2400 μg/l)
– http://www.who.int/water_sanitation_health/publications/20
11/dwq_guidelines/en/#
• WHO, March 2011.
Safe drinking-water from desalination
– Boron and borate
(…)
– http://www.who.int/water_sanitation_health/publications/20
11/desalination_guidance/en/index.html

Most Relevant References
• Al-Busaidi, A. (2004). Desalination in Oman and the fundamentals of reverse osmosis design.
Sultanate of Oman, Ministry of Housing, Electricity and Water.
• Hilal, N., Kim, G.J., Somerfield, C. (2010). Boron removal from saline water: A comprehensive
review. Desalination, 223, pp. 10-23.
• Kabay, N., Guler, E., Bryjak, M. (2010). Boron in seawater and methods for its separation - A
review. Desalination, 261, pp. 212-217.
• Ministry of Commerce and Industry (2006). Omani Standards for unbottled drinking water.
Directorate for Specifications and Measurement (OS 8/2006), p. 6.
http://www.pdo.co.om/hseforcontractors/blocks/documentation/docs/laws/Omani%20St%20Eng-full.pdf
• UK Expert group on vitamins and minerals (2002). Revised review of boron.
http://www.food.gov.uk/multimedia/pdfs/boron.pdf
• U.S. EPA (2004). Toxicological review of boron and compounds (CAS 7440-42-8). U.S.
Environmental Protection Agency, Washington, DC. EPA 635/04/052.
http://www.epa.gov/ncea/iris/toxreviews/0410tr.pdf
• WHO (2008). Guidelines for drinking water quality, 3rd Ed., World Health Organization.
http://www.who.int/water_sanitation_health/dwq/fulltext.pdf
• WHO (2009). Boron in drinking-water: Background document for development of WHO Guidelines
for drinking-water quality. World Health Organization.
http://whqlibdoc.who.int/hq/2009/WHO_HSE_WSH_09.01_2_eng.pdf
• WHO (2011). Safe drinking-water from desalination. World Health Organization.
http://www.who.int/water_sanitation_health/publications/2011/desalination_guidance/en/index.html
• WHO (2011). Guidelines for Drinking-water Quality. 4th Ed. World Health Organization.
http://www.who.int/water_sanitation_health/publications/2011/dwq_guidelines/en/#

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R. Klingbeil, 2011: Boron Concentrations in Desalinated Water: A Real Threat? Review of Health Issues, Technical Aspects and International Guidelines