Abstract: check involvement of parameters in degradation process of

Abstract:
In this study it is mainly focused on degradation of phthalates in beverage
level containers and how to eliminate them after the contamination has been
done. Phthalate is very largely used (82 % of entire plasticizers) in polymer
industry as a plasticizer. There are lots of adverse effects of those
plasticizers when they are in contact with human body such as reproduction
system malfunctions and high cancer risks. There have been different
experiments to check different variables that are involving in degradation
process. It is very important to remove leeched phthalates from water or
beverage to at least secure level to human body. This paper identifies the
effects on human body of phthalates, various experiences that have been done to
check involvement of parameters in degradation process of phthalates and
finally studies on suitable removal methods.

Keywords:
DEHP; Plasticizer; Degradation; Exposure; Cancer Risk; Removal Methods

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1.   
Introduction

Plastics are hard
and brittle without additives so it is essential to add those things to
polymers. There is no chemical bond between phthalates and the
PVC with which they have been mixed. Consequently, they can evaporate or be
leached out of the plastic and migrate to food. Thus they also enter the
body: through respiration, ingestion in food, and skin exposure. First of
all it is very important to identify what is the reason to emphasize this
research area. The most active type of phthalate is DiEthyl Terephthalate
(DEHP). It is known to have the highest concentrations in leeched samples. So
here onwards the study is more focused on DEHP.

Figure 1: Typical GC/MS chromatogram
of PET bottle

 

 

 

2.      Adverse effects on human body of
phthalates

There have been experienced a lot of
adverse effects on human body of phthalates.
e.g., effects on endocrine balance and reproductive capacity and disruption of
the immune and nervous systems. (“A variety of environmentally persistent
chemicals, including some phthalate plasticizers, are weakly estrogenic.,” n.d.) There are many researches which relevant to the
topic, more of them are based on the health impacts on exposure to the
phthalates. A number of researchers have been tried to figure out the exact
threat to the living tissues but there is huge knowledge gap when it comes to
human exposure. In first case study
adult, regularly cycling Sprague-Dawley rats were used as test specimens. In
this study they focused on female hormone levels after the exposure to DEHP and
exposure resulted in prolonged estrous cycles and many anomalies in female
hormone levels which regard to reproduction. (Davis, Maronpot, & Heindel, 1994) . In next case study they used female Long
Evans Rats to study the effects of the exposure to the Di-Ethylhexyl Phthalate
(DEHP). Mainly they focused on the effects on offspring of rats in this study.
They observed a significant decrease in kidney and testes relative weight
(organ/body weight) with a significant increase in relative liver weight after
the exposure has been done. (Arcadi et al., 1998) .
Since that high potential to attack the ovary DEHP may also be a reproductive
toxicant in women too.

3.     
Contradictory findings that emphasize phthalates
are not harmful at all!

In first one it is said that lead phthalates are not
carcinogen under any known condition. (Doull et al.,
1999)
.The total weight-of evidence from mutagenicity studies clearly indicates that
DEHP is not genotoxic. This conclusion is based on negative findings in a wide
range of test systems to determine in vitro bacterial, yeast, insect,
and mammalian cell mutagenesis, DNA interactions, and chromosomal aberrations
both in vitro and in vivo.

There have been studies to observe the expulsion of
phthalates after oral injection to human body. In contrast to previous studies,(Koch, Bolt,
Preuss, & Angerer, 2005)  most of
the orally administered DEHP is systemically absorbed and excreted in urine. No
dose dependency in metabolism and excretion was observed.

Those are just main studies that were conducted on the
subject. People at risk for reproductive toxicity of DEHP are likely to include
those exposed occupationally as well as those exposed during medical procedures
such as dialysis or blood transfusion. Of particular concern is DEHP exposure
in newborns, who receive among the highest doses in the population from blood
transfusions, extracorporeal membrane oxygenation, and respiratory therapy. (Tickner,
Schettler, Guidotti, McCally, & Rossi, 2001). Based on recent studies by
the CDC, exposure to phthalate esters is widespread and occurs at higher levels
than previously anticipated. (Barr et al.,
2003)
.

4.     
Different
studies to check involvements of parameters in degradation process of
phthalates

 

There was a study to establish
involvement to migration of phthalates with parameters like: type of phthalate
used in the container, type of preservative used and the ph value of the sample. The analysis included 45 samples
of products packed in containers made from polyethylene terephthalate. The
samples were divided into 5 groups: group 1 (N=9), soft drinks preserved with
orthophosphoric acid; group 2 (N=14), soft drinks preserved with Na-benzoate;
group 3 (N=5), soft drinks preserved with K-sorbate; group 4 (N=8), soft drinks
preserved with a combination of Na-benzoate and K-sorbate; and group 5 (N=9),
mineral water without preservatives.T he samples were analyzed by the method of gas chromatography.
The highest rate of migration to soft drinks was recorded for dimethyl
phthalate, ranging from 53.51 to 92.73 % that fact is also supported by the
experiment of (Keresztes, Tatár, Czégény,
Záray, & Mihucz, 2013), whereas dibutyl phthalate and
diethylhexyl phthalate showed highest rate of migration to the mineral water
(56.04 and 43.42 %, respectively). The highest level of phthalate migration
from plastic containers to soft drinks was found in the products preserved with
K-sorbate.

 

Definitely the phthalate leech
ability depended on the ph value of the sample. With the lower ph values the
migration levels were higher. Dimethyl phthalate showed highest migration to
preserved drinks as an acidic medium.  Almost in
every beverage or soft drink an acidic media is used to store the drink.
(Embedded carbon di-oxide media which gives low PH value to the sample)  (Bošnir et al., 2007) 
There were studies that were conducting using soda and vinegar and same
conclusion was drawn at that time. (Sax, 2010)

When it comes
to phthalate level in drinking water the maximum level of DEHP is 6.0 ?g /l by US EPA (2009) standards. Most of the samples
(80%) analysed are below that limit at purchase but after two weeks of storage
at room temperature only 20% are below the regulation. Furthermore if we consider the limit of World Health Organisation
(WHO), which is 8.0 ?g/l, all the water samples at purchase time were below
regulation for DEHP concentration. Also he found
out there is effect on whether the polymer is virgin type or recycled polymer.

 

Concentration of the phthalates is increased by time and
temperature. Here they used 3 conditions at purchase, water stored at fridge (40
C) and water stored at room temperature (240C). Even the samples are
stored at low temperature it appears a slightly increasing in each compound
concentration. In natural
mineral water samples growth rate of phthalates concentration is higher than
the carbonated water samples. (“DETERMINATION OF PHTHALATES
FROM BOTTLED WATER BY GC-MS – ProQuest,” n.d.) 

Figure 2:  The
effect of storage temperature (22 °C, 40 °C, 50 °C and 60 °C) on DEHP
concentration for three different non-carbonated mineral water samples bottled
in 0.5-L PET containers

 

5.     
Effect of
prolonged exposure

The result of this matter is quite way around and it has
shown that there is no relationship in this matter.(Keresztes et al., 2013) found that there is no significant relationship between
phthalate degradation and temperature in his research he used maximum
temperature of 60 0C.

 

Figure 3: The effect of prolonged exposure time (24 h, 48
h, 72 h) at 60 °C on the DEHP concentration for three different non-carbonated mineral
water samples bottled in 0.5-L PET containers.

 

6.     
Effect on the
storage time of the sample

The aging of the samples do have positive effect on
phthalate migration to the samples. They could detect DEHP after 44 days of
storage at 22 °C at traceable level. When it was stored over 1200 days the
amount of DEHP level was remarkably high. (Keresztes et al., 2013)

Figure 4: Evolution of phthalate concentration in non-carbonated
mineral water bottled in 2.0-L PET containers over time.

7.     
Effect
of Surface Area/ Volume

The rate of phthalate migration is also affected by the
surface/volume ratio. Higher ratios result higher migrations. Mineral water
purchased in PET bottles of 0.5 L had the highest phthalate concentrations
compared to those obtained for waters of the identical brand bottled in 1.5-L or
2.0-L PET containers due to the higher surface/volume ratio.(Keresztes et al., 2013)

Figure 5: The effect of contact surface area of 0.5-L,
1.5-L and 2.0-L PET bottles on the Phthalate concentration of non carbonated
mineral water.

 

8.     
Studies
on using nano materials to remove leeched particles

There are lot of studies that
support the fact that nano materials are efficient in removing contaminants
that are considered as toxic added to the water.  Those nano materials serve the purpose by
different mechanisms such as adsorption, desorption, oxidation, reduction,
precipitation, dissociation and ion exchange. (“Kinetics
and thermodynamics of cadmium ion removal by adsorption onto nano zerovalent
iron particles – ScienceDirect,” n.d.) Characteristics of nano particles such as pH of zero-point
charge (Liang, Dai, Zhou, & Zhang,
2014),
adsorption properties like surface area and pore distribution (R, Me, Ms, & Ha, 2015), crystal structure and
size (Dave & Chopda, 2014) are important in
determining the removal efficiency of toxic constituents from water.

 

Different
nano iron oxides (e.g. Titanium oxides, maghemite, goethite, Aluminium Oxides,
hematite) have shown ability to remove toxic constituents by mechanisms of
adsorption and desorption (Hua, et al., 2012). In this study it was found that Tio2
is capable of removing particles Zn, Cd, Pb, Ni like heavy metal ions.  Nano sized ferric oxide has been reported to
be a low-cost adsorbent that can be used for removal of toxic metals in water
and secondary contamination of the ferric oxide is known to be negligible(Lee & Park, 2013). Nano sized
manganese oxide has been shown high performance in sorption of cationic and
anionic pollutants, arsenic and phosphate when present in water(Takamatshu, et al., 1989).Nano sized aluminum
oxide has been reported as an excellent adsorbent for removing different heavy
metals such as chromium, cadmium, lead, nickel, cobalt and manganese(Boparai & Joseph, 2013). There are catalyst
groups to sorption ability of Aluminium metal such as nitrate, phosphate, carboxylic
and sulphate (Stietiya & Wang, 2014). Titanium oxide nano
particles have been used for simultaneous removal of multiple heavy metals such
as Zinc, Lead, Cadmium, Nickel and Copper by adsorption (Hua, et al., 2012). Photocatalytic
properties of nano titanium oxide have been attributed with advance oxidation
capacity for removal of toxic constituents from water (Lee & Park, 2013). Nano Zinc oxide has
been used as an effective adsorbent for removal of H2S, Copper and
Lead in water (Wang, et al., 2010). Nano magnesium particles have been
considered as a superior adsorbent for removal of heavy metals. 

 

Therefore,
based on the findings of previous research, use of nano materials seem to be a
prominent solution to remove toxic constituents that could be present in both
water and beverages. Development of a low-cost adsorbent using nano materials
will be a novel approach to provide safe products for industrial people and
also to general public.

Titanium
dioxide is commercially available and easy to make by hydrolysis.

 

9.     
Conclusion

When
we use phthalates as plasticizers to add polymers, different kinds of phthalates
leech out from polymer matrix to beverage product. Even that degradation
process happens under room temperature and atmospheric conditions. This leech
out process is governed by many reasons. Even though there have been many
studies to check involvement in those factors some outcomes of those
experiments are confusing. So that it is necessary to do proper research to
check those confusing outcomes. When it comes to Sri Lankan beverage level
containers and PET water bottle industry there is necessity to find out if
degradation level is within the allowable range. That becomes a critical matter
with reputation of low quality products in Sri Lanka. In addition to that
nowadays there is huge consumption of soft drinks and beverage products.

Those
leeched phthalates are certainly risk to health of population. Like in above
matter even though there have been many researches on this matter results are
confusing. Actually there have not been experiments that were conducted on
human subjects and also have been only very few studies on the matter. So it is
safe to assume those phthalates are problematic to human health.

In
removing heavy metals from solutions it is clear nano materials are efficient,
but there have not been enough experiments decide whether nano materials are
effective or not when it comes to phthalates. So purpose of this research is to
check efficiency of Tio2 as nano material to remove phthalates from
different beverages.           

10.  References

 

Jobling, S., Reynolds, T.,
White, R., Parker, M. G., & Sumpter, J. P. (1995, June). A variety of
environmentally persistent chemicals, including some phthalate plasticizers,
are weakly estrogenic. Retrieved January 21, 2018, from
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1519124/

J, D. B., M., R, R., H.,
& J, J. (2002, April 24). Di-(2-ethylhexyl) Phthalate Suppresses Estradiol
and Ovulation in Cycling Rats. Retrieved January 21, 2018, from
http://www.sciencedirect.com/science/article/pii/S0041008X84712002

Costaa, C., Arcadia, F. A.,
Imperatorea, C., Marcheseb, A., Rapisardac, R., Salemia, M., . . . Costaa, G.
(1999, January 23). Oral Toxicity of Bis(2-Ethylhexyl) Phthalate During
Pregnancy and Suckling in the Long–Evans Rat. Retrieved January 21, 2018, from
http://www.sciencedirect.com/science/article/pii/S0278691598000659

J. D., R. C., C. E., B. G., J. S., C. W., . . .
M. V. (2002, May 25). A Cancer Risk Assessment of Di(2-ethylhexyl)phthalate:
Application