Is it possible to use Aquatic Moss (Warnstorfia fluitans) for hyperfiltering of arsenic from water?

Abstract

The presence of the high-level carcinogenic metalloid arsenic (As) in groundwater is one of the major environmental catastrophes, which has still to be solved in a sustainable ways. One eco-friendly solution by using plant-based remediation or phytoremediation technology especially phytofiltration could be implemented, since a number of aquatic plant species those can accumulate high concentration of As from the water have been discovered in recent years. In the northern part of Sweden, the As content in groundwater is high due to mining activities and local geological condition. In this As contaminated water in the cold climate, the aquatic moss species (Warnstorfia fluitans) was found growing. Our hypothesis was that since this moss species could grow in that high As content water system, it would possibly also take up As to high extent. The aim of this study was to investigate this moss for filtering or removal of As from the contaminated water system under laboratory condition. Besides these, the As speciation in the moss was also investigated. Our results showed that this W. fluitans could remove more than 80% of As from the water system with 74μg arsenate/L within 1 hour. The total As concentration analysis with hydride generated Atomic absorption spectrophotometry (HG-AAS) of this aquatic moss has found, it could accumulate more than 4000mg As Kg DW-1 from 7.4mgAs/L and the major part of the accumulated As present in the moss was arsenate, independent of arsenite or arsenate added. The As uptake in moss result fit our hypothesis that W. fluitans could accumulate a high level of As from the water and may clean contaminated water systems. In conclusion, the laboratory experiments have given hints that this aquatic moss has the potentiality for hyperfiltering water from As in the temperate climatic regions.

Full text

Possibilities for using the aquatic moss
Warnstorfia fluitans as arsenic hyperfilter
Arifin Sandhi
Stockholm University, SE-106 91, SWEDEN
KTH Royal Institute of Technology, SE-10044, SWEDEN

Arsenic
● Arsenic (As) is one of the
major carcinogenic elements.
● Both inorganic (As5; As3) and
organic species (DMA, MMA).
● Maximum tolerable limit in
drinking water (10µg/L),
agriculture water (100µg/L).
● In Sweden, As contamination
occurs by mining, smelting,
wood impregnation process.
SGU,%2012%

Mining activities in N. Sweden
● Most mining activities
occur in northern part of
Sweden.
● A number of iron mines
releases arsenic.
● In Sweden, 26% of the
contaminated areas have
arsenic as their primary
contaminant.

As Remediation techniques
Soil
● Stabilization, capping or soil replacement
● Excavation, removal or disposal in landfill
● ‘Wet and dry’ care system in mining areas
Water
● Arsenic oxidation
● Coagulation
● Ion exchanges & membrane technologies
● Adsorption

Green%plants%are%used%to%
engulf,%eliminate%or%
render%environmental%
contaminants%harmless%
Phytoremediation

As uptake and phytofiltration
Metal accumulation points (black dots) in different types of
plant species in emergent and submerged conditions.
Emergent Submerged

As uptake in aquatic plants
! Native aquatic moss
(Warnstorfia fluitans) from
Sweden.
! Adapted to low nutrient
conditions.
! Grows in As rich surface water
from mining areas in northern
Sweden (Skellefteå field).
! Adapted to high As
concentration (100-200µg/L) in
water.

Aim
To investigate the potential use of this aquatic
moss (W. fluitans) for arsenic phytofiltration in the
mining areas.

Objectives
To investigate if Warnstorfia fluitans
● Accumulates high levels of arsenic from the water system
● Accumulates both inorganic arsenic species from water.
● Arsenic absorption and adsorption both occurs.
● Can be used in constructed wetland system
01/08/17 /Name Name, Institution or similar

Materials and Methods
● Moss mats were collected from the
Skellefteå field in SWEDEN.
● A number of inorganic arsenic
concentrations (1, 10, 100µM) was
used in this investigation.
● HG-AAS used for total arsenic analysis
in moss biomass and water.
● HPLC- AAS also used for arsenic
speciation analysis in moss biomass.
● Both greenhouse and climate chamber
facilities was used.

Objectives
To investigate if Warnstorfia fluitans
● Accumulates high levels of arsenic from the water system
● Accumulates both inorganic arsenic species from water.
● Arsenic absorption and adsorption both occurs.
● Can be used in constructed wetland system

Arsenic accumulation in arsenate and
Hoagland nutrient (%) soln. for 192hrs
Fastest As removal from water occurs at low
nutrient and low As concentration (1µM).
Sandhi,%Landberg%and%Greger%submi=ed%

Arsenic accumulation in arsenate (µM) and
Hoagland nutrient (%) soln. in 192hrs
W. fluitans could
accumulate more than
4000mg As kg DW-1
from 100µM arsenate
treated medium.
Sandhi,%Landberg%and%Greger%submi=ed%

Objectives
To investigate if Warnstorfia fluitans
● Accumulates high levels of arsenic from the water system
● Accumulates both inorganic arsenic species from water.
● Arsenic absorption and adsorption both occurs.
● Can be used in constructed wetland system
01/08/17

Inorganic arsenic species accumulation
72 h, 10µM arsenate or arsenite
Available arsenic is mostly
present as arsenate in moss
and most accumulated arsenic
is tightly bound in moss pellet
Sandhi,%Landberg%and%Greger%submi=ed%

Objectives
To investigate if Warnstorfia fluitans
● Accumulates high levels of arsenic from the water system
● Accumulates both inorganic arsenic species from water.
● Arsenic absorption and adsorption both occurs.
● Can be used in constructed wetland system

Arsenic absorption & adsorption
24h, 10µM arsenate & 1% Hoagland soln.
Arsenic%absorp?on%(living%
part)%was%significantly%
higher%than%adsorp?on%
(dead%part)%in%this%aqua?c%
moss%
Sandhi,%Landberg%and%Greger%submi=ed%

Objectives
To investigate if Warnstorfia fluitans
● Accumulates high level of arsenic from the water system
● Accumulates both inorganic arsenic species from water.
● Arsenic absorption and adsorption both occurs in this
moss.
● Can be used in constructed wetland system

Using W. fluitans in a constructed
wetland
Moss-based%
constructed%
wetland%system%
As#content#in#le+uce#leaves#was#reduced#by#low#water#inlet#flow#(1.5mL/min)#in#moss#based#
wetland#system.#
Two%water%inlet%flow%
speeds;%1.5mL/min%
(low)%and%5%mL/min%
(high)%
ab% ab%
a% a
ac%
EU%max.%
limit%for%As%
cont.%rice%
19

Conclusions
● High level of As accumulation occurred in W.
fluitans within short time duration and minimum
nutrient conditions.
● Both inorganic arsenic species were accumulated
in W. fluitans.
● Arsenic is more absorbed than adsorbed.
● Arsenic content could be reduced in water in a
constructed wetland system.

Acknowledgements
● Maria Greger, Plant Metal Group,
Dept. of Ecology, Environment and
Plant Sciences, Stockholm
University, SWEDEN
● Land & Water Resources
Engineering Division, Dept. of
Sustainable Development,
Environmental Science and
Engineering, KTH Royal Institute
of Technology, SWEDEN

Thank#You#All#
Arifin.sandhi@su.se%
Twi=er:%sandhieco%