Journal of Tea Science Research. 2015, Vol. 5, No. 10, 1-4
2
The heavy metals present in food and beverages are
detrimental to human health and most countries
restrict the concentration of metals like lead,
cadmium etc. The non-edaphic factors that are
potentially contributing to the occurrence of Pb in
made tea have been investigated. A review on
literature revealed that some work has been done on
Pb accumulation in tea and are mainly attributed to
industrial activity through the precipitation of
atmospheric lead (Jin et al., 2005a) and surface dust
contaminations through vehicular pollution (Han et
al., 2006). Except for some work on these line
carried out in plants like Tobacco on long term usage
of copper fungicides (Semu and Singh, 1996),
informations on tea is limited. An attempt has been
made to investigate Pb contamination in tea due to
application of COC formulation for the control of
blister blight in tea plantations in south India.
1 Results and discussion
Elemental concentrations in the formulated fungicides
are compared with FAO specifications. The results
are summarized in Table 1. The results indicated that
all the brands of copper oxychloride formulations tested
contained impurities lower than the FAO
specifications, except for four samples which showed
slightly higher amount of Pb (<250 mg kg
-1
) and eight
samples contained low amount of Pb (<50 mg kg
-1
).
As COC contained heavy metal impurities, its
repeated application to control blister blight disease
during monsoon months enhanced the heavy metal
concentration, particularly Pb, in harvestable crop
shoots. The first foliar application of COC had no
significant Pb content in black tea (Table 2). But
subsequent applications of COC increased Pb
content in the harvested shoots. COC application
along with hexaconazole showed a no increase in Pb
content. Results indicated that repeated applications
of COC singly or in combination with hexaconazole
resulted in the accumulation of Pb. However,
continuous application of COC did not show
significant result in Pb accumulation beyond the
threshold level in black tea. This may be due to the
rainfall intensity during the application of COC and
or higher leaf wetness which hindered the retention
Table 1 Heavy metal contents of copper oxychloride
Copper oxychloride
Pb content in mg kg
-1
Brand
- 1
21.24 - 49.76
Brand
- 2
180.22 – 270.59
Brand – 3
66.21 – 119.18
Brand – 4
114.84 – 265.14
of foliar applied COC.
Jin et al. (2005b) reported that the increment in Pb
concentration in black tea manufactured by CTC
process may be attributed to the contamination of Pb
impurity from the metal surface of the machine. The
present study concluded that there is a strong
possibility of Pd getting accumulated through
the fungicide formulations. Application of impure
copper fungicide formulations to tea leaves could
increase the accumulation of heavy metals such as
Pb in black tea, thus increasing the health hazards
and the ecological risks due to excessive
application of chemicals on tea.
2 Conclusions
As a practice, before application in the field, these
agro inputs should be analysed by the estates for
their suitability as per national standards.
3 Materials and methods
3.1 Sampling
Wettable powder formulations (50%) of four
different brands consisting of thirty fungicide
samples were collected from commercial market,
local garden supply stores, and local tea gardens. All
the samples were suitably labeled.
3.2 Field experiments
In tea, the contact fungicide COC is applied in
combination with systemic fungicides to protect the
plants from the incidence of blister blight disease
caused by the fungus,
Exobasidium vexans
Massae
(Chandra Mouli, 1993). Foliar application of COC is
done at short intervals ranging from 5 to 7 days
through out the monsoon period (Premkumar and
