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Chemical Oceanography of Harbour and Coastal Environment of Visakhapatnam (Bay of Bengal): Part I- Trace Metals in Water and Particulate Matter

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Indian Journal of Marine Sciences Vol. 14,September 1985, pp. 139-146

Chemical Oceanography of Harbour & Coastal Environment of Visakhapatnam (Bay of Bengal): Part I-Trace Metals

in Water & Particulate Matter

D SATYANARAYANA, 1M RAO&B R PRASADA REDDY School of Chemistry, Andhra University, Visakhapatnam 53000.3.

Received 11 October 1984; revised received 31 May 1985

Concentrations of Fe, Mn, Cu, Ni, Zn, Pb, Cd and Co in surface and bottom waters are higher in dissolved and particulate forms in the harbour as compared to their concentration levels in coastal waters. This may be attributed mainly to the discharge 'of industrial effluents and domestic sewage into the harbour. ThouSh the trace metal concentrations in coastal waters of Visakhapatnam are higher than the average values of Indian ocean, they are however, lower than those reported for coastal and inshore waters of Bay of Bengal. The dissolved trace metals, in general, show relatively higher values in monsoon whereas the particulate fraction shows higher values in post/premonsoon seasons. Significant correlations are observed between some dissolved and particulate trace metals, total suspended matter (TSM), and chlorophyll a indicating their common association with these fractions.

Information on the distribution and concentration levels of trace metals in the coastal environment is essential to assess their accumulation in organisms and their possible transfer to man through food chain.

Though there are several reports on the concentration levels of trace metals in Indian coastal waters1-10 no report is available concerning these in waters of Visakhapatnam coast. The present paper deals with the concentration levels of dissolved and particulate trace metals (Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb) in surface and bottom waters of harbour and coastal regions of Visakhapatnam.

Materials and Methods

Area of investigation and station locations are showin in Fig. l. About 12 x106 tonnes of cargo consisting of ores, fertilizers, rock phosphate, oil and petroleum products, food grains, coal, coke, etc. are handled annually through Visakhapatnam harbour11 .

A major part of the city's sewage enters into the inner harbour through sts 3 and 5. Most of the industrial effluents (of fertilisers, zinc smelter, petroleum refinery, etc.) are drained into st 2. Extensive low lying swampy areas with mangrove and scrub vegetation are found boardering the north and northwest periphery of the harbour. The inner harbour is mostly a restricted area and has no effective means of flushing out the effluents into the open sea due to inadequate tidal flushing and near stagnant conditions prevailing in this area.

Water samples were collected monthly (Feb. 1982to

Jan. 1984) both at surface and bottom at 8 stations in Fig. I-Station locations in (a) harbour and (b) coastal. waters 139

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INDIAN J MAR SCI, VOL. 14, SEPTEMBER 1985

the harbour. Water samples at different depths were also collected at sts 9-13 (Dec. 1983) in coastal region north of Visakhapatnam. Surface samples were collected using a clean plastic bucket and bottom samples using Niskin water samplers. They were immediately filtered through pre-weighed 0.45flll1

membrane (Millipore HA) filters. The filtered water samples were stored after acidifying with pure HCl to pH 2-3. The filters containing the particulate matter were air dried and stored in a vacuum desiccator for trace metal analyses. Dissolved trace metals (Fe, Cu, Ni, Zn, Pb, Cd and Co) were analysed by atomic absorption spectrophotometry (AAS) using am- monium pyrrolidine dithiocarbomate (APDq-methyl isobutyl ketone (MIBK) extraction 12. Mn was determined separately by AAS using sodium diethyl dithiocarbomate (Na-DDq-MIBK extraction. Filters containing particulate matter for trace metal analyses and blanks were digested with a mixture ofHCI04 and HN03• Residues after dilution to 25 ml with HCl (0.1 N) were subjected to AAS.

Total suspended matter (TSM) was determined by filtering 21 of seawater sample through a pre-weighed

0.45J.lm membrane (Millipore HA) filter, washing it with distilled water to remove salts, drying the filter at 85°C and weighing it again.

Shimadzu atomic absorption spectrophotometer (Type, AA-640-12) with air-acetylene fuel mixture was employed for AAS determinations. A. Toshniwal Digital pH meter (Type CL 44) was used for pH measurements.

The precision of analyses, determined from 16 samples (each in duplicate), presented as standard deviation and percent coefficient of variation varied from 0.06 to 0.36 and 0.4 to 4.1 respectively for various metals.

Results and Discussion

Annual averages of dissolved and particulate trace metals in harbour are given in Tables I and 2 and the distribution of trace metals in coastal waters is shown in Table 3.

Iron-In

general, bottom values were higher than the surface for both dissolved and particulate Fe. This can be attributed to the presence of considerable amounts of organic matter with which Fe forms both soluble and insoluble metal chelates1. Colloidal hydrous oxide is also responsible for higher concentration of Fe in particulate matter1•The release of Fe from the sediments due to turbulence may be partly responsible for the local excess of dissolved Fe in bottom waters6•7. Highest concentration of (dissolved and particulate) Fe was observed at st 8 where large quantities of Fe ore are handled. The coastal waters, in

140

general, showed higher values of dissolved and particulate Fe in the bottom than in the surface.

Manganese-Higher concentrations of Mn were observed for both the fractions in surface than in bottom waters which may be mainly due to the land input. It is interesting to note that while st 5 recorded highest value of dissolved Mn, the particulate Mn registered highest value at st 3 both in surface and bottom waters. Highest value of dissolved Mn at st 5 is due to the drainage of domestic sewage from the city and near anoxic conditionsl3,14 prevailing at this station which facilitate the dissolution of Mn by the reduction ofMn4 +to Mn2+ .Maximum concentration of particulate Mn at st 3 may be due to the spillage of Mn dust during ore handling. Though the spillage could have normally resulted in increase of dissolved Mn, pH conditions at this station (7.6-8.1) are more favourable for flocculation rather than dissolution.

Extensive accumulation of organic matter15 with which Mn normally associates is also partly responsible for the high concentration of particulate Mn at this station. In coastal waters dissolved and particulate Mn showed enrichment in surface waters which may be due to its diffusion from shelf sediments and the deposition of atmospheric particulatesl6.

Copper--Bottom waters showed higher values of Cu than surface in the harbour. Some of the organisms are known to concentrate significant amounts ofCu in seawater1. Relatively higher concentration of Cu at the bottom may be due to the release of this element from organisms during their decomposition 1.Presence of high organic matter with which Cu forms soluble and insoluble metal chelates is also responsible for the high concentration in bottom waters15.Highest values of dissolved and particulate Cu were recorded at st 3 both in surface and bottom waters which may be attributed to the intense biological activity and excessive amounts of organic matter present at this station 15.Both dissolved and particulate Cu in coastal waters showed enrichment in the bottom.

Nickel-Both dissolved and particulate fractions of Ni registered higher values at the bottom. Highest concentration ofNi was observed at st 2 which receives large quantities of industrial effluents. Bottom waters showed relatively higher values of Ni in dissolved and particulate fractions in the coastal region.

Zinc-Concentration of dissolved and particulate Zn was higher in surface than in bottom waters. This may probably be due to the drainage of domestic sewage and industrial effluents into the inner harbour and their dissipation into the coastal region. Sen Gupta et al.1also reported high concentration of Zn in the coastal waters of Bombay. Dissolved and

I

~'

I ~:~ ; I; II 'I

"

(3)

-~~--~->,,,,-=~--.,....~~..- -!::;,'?~....;:;;.;::,:...::-.~::-:,:~~~"'~':':::2"s;.:~~;.~' Table1~DissolvedTraceMetalConcentrationsofVisakhapatnamHarbour [Results,annualaverage,areexpressedinItg.1-1] Station

De-pthFeMnCuNiZnPbCdCo (m)

--

8283B283828382838283828382838283en ;>

-l

-<Innerharbour;> Z 1 S12.011.314.618.67.54.83.91.95624004.34.91.60.90.60.7;> ;:08

1012.112.312.319.033.720.63.53.42292176.313.70.70.80.80.3;>

-<;>

Z2

S11.411.088.963.75.13.05.62.8122810833.13.72.92.31.51.1;> 13

1016.99.017.224.338.621.64.33.72783336.313.51.51.51.40.6~ I:lr:-

-l

3S7.29.217.617.316.010.23.71.92702684.97.21.20.80.90.4;:0 10

10.914.812.217.058.836.93.7

3.32011799.817.5 0.50.60.70.3;> 8(') m 3:4

S6.75.554.731.24.62.53.82.08036573.33.91.31.00.70.5m

-l

8 1311.615.117.420.925.6 16.83.83.32021985.811.20.80.80.60.3;>

l'

en 5 S12.99.690.677.011.62.24.51.72982564.24.31.00.41.00.4Z 8 611.314.941.136.024.228.94.23.42481936.912.60.90.70.70.4~ ;>I'

-l

mI ;:0Outerharbour

P.<> .";>;:06S8.39.844.020.14.62.13.41.83944082.94.21.00.61.10.4

-l

[J

fi

1311.817.810.615.325.817.52.93.31781605.713.20.70.60.80.4 ;>

l'

c:7 S15.616.323.910.23.92.23.31.74282232.63.61.10.50.70.3

-l.

m 2 1512.817.9879.810.024.620.42.73.11406.60.50.50.60.214.23: ;> ~8 S20.819.512.313.83.42.02.71.51901282.83.6('.70.30.70.3m ;:03 1823.724.8

7.28.234.921.43.43.2157957.813.10.60.40.8C.2 S=surface.B=bottom \~

(4)

-

•.... t..J ----~-_...~----_._---.._-

---

Table2--ParticulateTraceMetalConcentrationsinVisakhapatnamHarbour [Results,annualaverage,areexpressedin-l1g.g-1drywt]::';-:3ti'Jn

Fe

UnCuNiZn

PbCdCoISM 82

8382838283828382838283828382838283 - Innerharbour ~- --

1 S8919103792177228614679.535.049.24671503217222322.313.431.523.916.117.2 3

11649125208359261110102542.285.32348219638811096.66.834.129.711.912.2 Z

tl

2 S111391114581286914767.268.584.16087575020522645.918.655.544.318.724.4

;;

3 1326512130975649160690382.090.629312504491127819.58.659.048.811.412.7Z

'-

~ 3 9729125472264253824015824.839.936853287375403;l> .:>10.36.752.030.115.017.1~ LJ

951810497105410482074153542.546.02387194775713812.04.049.235.812.311.4en

p

<:4S9963110681943187598.658.331.654.35440523017224121.212.245.631.317.414.6

0

t""'B1245312818875667110366942.750.1243115574426784.34.643.734.812.413.0

.

.,.en5S9981105371420183419112230.731.84445456019823217.211.540.823.018.319.8t'T1 "tl 8 1183110626670580117582242.030.0276716103828525.64.440.627.013.313.8..., t'T1~b:It'T1Outerharbour~ ::000v. 6

S10638123261478164413767.428.963.04950364414928813.27.433.821.715.015.8 B

1339815087911410 910602 36.856.12.85.736.627.112.92236170927156013.0 7 S9481130801464148914567.436.338.544193428 14624012.78.527.021.614.612.5 B

1550917556757330101259145.253.0200015582195534.75.328.225.612.813.5

i

8 S12107136601188762 13886.036.141.8 415525561652367.44.722.019.712.210.610 8

1925420423348245118177642.355.0190314552936572.63.328.524.812.712.4

I

!!

I

TSM=totalsuspendedmatter(mg.I-1),S=surface,B=bottom

i

I

I I

~.~

r

(5)

Table

3-

TraceMetalConcentrationsinCoastalWatersofVisakhapatnam [Concentration:Dissolved.Jig.

I-I;

particulate.Jig.g-IdrywtandTSM.Jig.

I-I]

Station

DepthFe MnCuNiZnPbCdCoISM(m)DP0P0P0P0P0P0PDPCIl :>

-l

-<0 14.412062.8208O.~

-

0.817.817.62706.62100.8NDND27.64.4:> Z106.914541.6~5.90.777.40.4NO32.22092.690.30.8NDNi)20.44.7:> 9 209.610311.841.497.10.616.4226"" 1.127.81.840.40.8NDND23.15.2:> 30

26.320853.1lCil51.12690.155.526.4~331.834.20.9NDND27.96.2-< :>5024.414452.278.51.21430.971.136.67531.82071.0NDND32.36.1Z :>~0 6.01340

-

224

-

26.41.110.022.01706.5142O.~NDNLJItl.94.4l:l :0- 10

8.028771.92201.72301.911.022.05473.5 2221.0I'DND51.14.7

-l

10

2011.01901

1.61151.02251.412.420.55044.4 201C.8},jl)ND57.84.2"" :>30

18.327841.91371.31401.88.517.64675.32270.9NOND23.35.2("') rn5017.827352.11572.12272.318.929.26654.41321.2NDND59.86.4s: rn

-l

0 11.122927.71392.925.41.023.62.962712.05860.6:> NDND40.75.9t"" 1831 4.961.6CIl 1016.71.851.81.024.55.952210.35221.0NDND42.95.6 Z112021.721006.464.53.3NQ2.875.017.629213.2 4691.6NDND22.45.4 30 44.131814.572.93.686.52.860.829.34358.83930.8lllDND60.45~4~ :>50 18.328455.377.56.23504.380.439.58998.84251.9NDND60.75.9

-l

rn""P:>013.17275.63361.820.50.815.611.72837.04010.9NDND25.84.7." 10 12.816402.22251.163.70.818.713.24~75.392.30.9NDND26.44.6:> ""122016.024071.61040.81102.025.822.01974.4 45.70.8NDNO25.24.6

-l

30 10.341992.42023.298.53.428.223.44536.11021.3NOND53.46.6(=i c:45

11.424723.02294.63553.733.535.16515.32221.0NDND18.27.3t"" :>

-l

rn 0 10.315074.91051.829.21.812.617.61977.92931.2NLJND22.45.4s: 10 13.515442.41101.54701.819.024.93664.42841.0NOND30.05.0:>

-l

13 2011.723773.565.73.21781.059.022.04174.42171.3NDND22.95.3

-l

rn3013.52789 2.776.82.33211.524.535.1442 7.92601.0NoND35.75.6"" 50 9.840634.034.34.34812.466.839.5933 5.31261.0NDND24.28.0 D=dissolved.P='particulate.TSM=totalsuspendedmatter.ND=non-detectable

-

~w

(6)

INDIAN J MAR seI, VOL. 14, SEPTEMBER 1985

particulate Zn registered highest concentrations at st 2 both in surface and bottom waters which maybe due to the discharge effluents from the zinc smelter containing high concentrations of Zn besides other trace metals like Pb, Cd, Co and Ni. Contrary to that in harbour, there is a definite enrichment of Zn at bottom in coastal waters which is due to its involvement in bio- geochemical cycle resulting in its removal from surface waters and regeneration in the bottom16.

Lead-Contrary to its normal behaviour, Pb registered slightly higher values in bottom than in surface in harbour waters. Highest values of Pb were observed at st3 both in surface and bottom waters mainly because of loading and unloading of large quantities of general and bulk cargo at this station.

Dissolved and particulate Pb in coastal waters showed enrichment in the surface primarily due to its anthropogenic input16 in this region.

Cadmium-Dissolved and particulate fractions of Cd recorded higher values in surface than in bottom waters in the harbour. St 2 which receives industrial effluents from zinc smelter registered highest values of Cd in dissolved and particulate fractions. Unlike in harbour, dissolved Cd in coastal stations showed relatively higher values in the bottom. The levels of particulate Cd are below the detection limit at all the stations.

Cobalt-Dissolved and particulate Co showed slight enrichment in surface and bottom waters respectively in harbour. Highest value of Co was observed at st 2 for both dissolved and particulate fractions. Concentration levels of dissolved Co were below the detection limit at all coastal stations.

Particulate Co showed slight enrichment in the bottom waters.

Total suspended matter (TSM)-Highest values of TSM were observed at st 2 in surface and at st 5 in bottom waters of the harbour which may be due to the influx of industrial effluents and domestic sewage (containing large amounts of suspended matter) into the respective channels. Highest value of TSM in surface water at st 2 was in good agreement with highest values of chlorophyll aand productivity 1 7. In coastal stations TSM values are significantly lower than those observed in harbour waters'.

Comparison of annual averages of trace metal concentrations in the harbour (Tables I and 2) showed relatively higher values of dissolved Mn, Cu, Ni, Co and Cd in surface and Cu and Co in bottom waters in 1982 than those in 1983. The concentration levels of particulate Cu and Cd in surface and Mn, Cu and Zn in

144

bottom are higher in 1982 than those in 1983.

However, dissolved and particulate Pb in surface and bottom, and particulate Ni and Co in surface showed relatively higher values in 1983 when compared with those in 1982. This may be due to the differences in land drainage and pollutant inputs into the harbour during this period.

No well defined seasonal variations was observed with all the metals either in dissolved or in particulate fractions. However, dissolved Fe, Mn, Zn, Pb and Co showed relatively higher values in monsoon while their particulate fractions exhibited relatively higher values in pre/postmonsoon seasons. Dissolved and parti- culate fractions of Cu showed relatively higher values in postmonsoon and that of Ni exhibited relatively higher values in premonsoon. While dissolved fraction of Cd recorded relatively higher value in postmon- soon, its particulate fraction showed higher values in premonsoon. This may be attributed to the interplay of several factors such as land drainage, flocculation, incorporation into phytoplankton and adsorption/d- esorption on/from suspended matter. Similar behaviour of trace metals (Fe, Mn and Cu) was reported in coastal and estuarine waters of Porto Nov06 and Goa7.

Correlation coefficients (r values at P<O.Ol) between dissolved and particulate trace metals, TSM and chlorophyll a were evaluated in order to understand the interrelationships among them. The results showed significant positive correlation between dissolved and particulate Cu(0.86), Pb(0.83), Zn(0.83) and Cd (0.88) in surface, and Cu(0.92), Pb(0.77), Zn (0.79), Cd (0.79) and Fe (0.82) in bottom waters indicating their association and possible exchange in these 2 fractions. Significant positive correlation is observed between particulate Zn(0.65) and Co(0.73) with TSM in surface suggesting that a major fraction of TSM comprises particulate Zn and Co. However, particulate Mn showed significant negative correlation

(-0.81)

with TSM in bottom waters. Significant

positive correlation is observed in surface between chlorophyll a and particulate Zn(0.70), Cd(0.89), and Co (0.67) indicating the uptake of these metals by phytoplankton.

A comparison of concentration levels of trace metals in harbour and coastal waters is shown in Table 4. Our results of coastal waters are also compared with those of coastal/inshore waters of Bay of Bengal3.5 and Indian ocean19•20. The present studies indicate that particulate Fe and, dissolved and particulate Mn, Cu and Zn both in surface and bottom are higher in harbour when compared with the coastal waters.

Dissolved Co and particulate Cd registered higher

~!l'il 1!l1! II .I

(7)

SATYANARA YANA et al.:TRACE METALS IN WATER &PARTICULATE MA TIER

Table 4-Comparison of Trace Metal Levels in Harbour and Coastal Waters of Visakhapatnam with Bay of Bengal and Indian Ocean

Metal

InnerOuterCoastalBay of BenqalIndian harbour

harbourregion

Coasta13 InshoreSOcean19,20 Sts 1-5

;;itsStS 9-136-8

--- ---

0 PPP00PPP0D0

Fe

5

9.710541118821391415.1141419.0

-

1.465.411.0 B

12.9 1173116871271218.116.3 Mn

S 47.420.73.6

-

2020.2310.9133812218015.3335 B

21.710.21155003.3822 Cu

5

6.8 1315.43.025.4

-

0.601071281.85.2202 B

30.624.13113.71202845 Ni

S 3.245.040.8 1.115.9

-

2.46.276.01.05.7 B

3.7 55.348.1 2.754.13.1 Zn

S 58325.448192953091715-38591.414.410.5231 B

2282268781136181036.0 Pb

S 4.42453.32048.0

32~

- -- - -

44 B

10.4 77622210.14265.1 Cd

S 1.318.09.00.8NO

-

0.07

- -

0.7

-

B

0.9 6.6ND4.11.20.6 Co

0.8243;;i37.827.195.0

- -

0.64.31.114NO B

0.628.5 ND40.339.00.5

S = surface, b = bottom, ND =non-detectable, D = dissolved (Jlg.l-I), P = particulate (Jlg.g -I dry wt)

values both in surface and bottom waters of the harbour. Concentrations of dissolved and particulate Ni in surface and Pb in bottom are higher in harbour than in coastal waters. The high concentration of these trace metals can be attributed mainly to the discharge of industrial effluents and domestic sewage into the harbour. Activities such as loading offerro-manganese ore and unloading of Zn-Pb ore concentrates and other general and bulk cargo also partly contribute to the enhanced levels of some of these trace metals in harbour waters.

The present results of dissolved and particulate trace metal concentrations in coastal waters of Visakhapatnam (Table 4) are, in general, higher than

those ofIndian ocean19.20. They are, however, lower when compared with those reported by Braganca and Sanzgiry3 for coastal and Rajendran et af.5 for inshore waterS of Bay of Bengal. This is probably due to the fact that their values represent predominantly those of river (Krishna, Godavari, Mahanadi and Ganga) mouths where the concentration levels of some of these

trace metals are significantly higher than their average values in the coastal region 3.

Acknowledgement

The authors express their gratitude to the authorities of Visakhapatnam Port Trust for according permission and providing mechanised boat for collection of water samples~One of the authors (BRPR) is thankful to CSIR, New Delhi for the award of a Research Fellowship.

References

I Sen Gupta R, Singhal S Y S&Sanzgiry S.Indian JMar Sci. 7 (1978) 295.

2 Sanzgiry S&Moraes C, Indian JMar Sci, 8 (1979) 254.

3 Braganca A&Sanzgiry S,Indian JMar Sci, 9 (1980) 283.

4 Sanzgiry S&Braganca A,Indian JMar Sci, 10 (1981) 238.

5 Rajendran A, De Sousa S N&Reddy C V G, Indian JMar Sci, 11

(1982) 43.

6 Jegatheesan G&Venugopalan V K,Indian JMar Sci. 2 (1973) I.

7 Kamat S B&Sankaranaryanan V N,Indian JMar Sci. 4(1975)

30&34.

145

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INDIAN JMAR SCI, VOL. 14, SEPTEMBER 1985

8 Sankaranarayanan V N & Stephen R, Indian J Mar Sci, 7 (1978) 201.

9 Vasanti M M, Ganapathy S&Pillai K C, IndianJMar Sci,10

(1981) 35.

10 Fondekar S P& Reddy C V G, Mahasagar-Bull Natn Inst Oceanogr, 7 (1974) 27.

II Visakhapatnam Port Trust, Statistical Bulletin, 1981-82.

12 Brewer P G, Spencer D W & Smith C L, Spec Tech Publ American Society for Testing Materials, 443 (1969) 70.

13 Sarma V V, Raju G R K&Bose Babu T, Mahasagar-Bull Nam Inst Oceanogr,15(1982) 15.

14 Ganapathi P N&Raman A V, IndianJ Mar Sci, 5 (1976) 251.

146

15 Raman A V&Ganapathi P N, Mar Poll Bull, 14 (1983) 46.

16 Bruland K W, in Chemical oceanography, Vol. 8, edited byJ P Riley&R Chester (Academic Press, London) 1983, pp. 161

& 183.

17 Satyanarayana D, Rao I M&Prasada Reddy B R (Unpublished data).

18 Brewer P G, in Chemical oceanography, Vol. I, 2nd edition, edited byJP Riley&G Skirrow (Academic Press, London) 1975, pp.427.

19 Chester R&Stoner JH, Mar Chern, 2 (1974) 17.

20 Chester R&Stoner J H, Nature Lond,255 (1975) 50.

t

References

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