Organochlorine contaminants in sediments of the Tauranga Harbour, New Zealand

Abstract

DDT, DDE, and DDD (up to 0.5 ng g -1 per compound) and traces of dieldrin (< 0.1 ng g -1 ), were detected in surficial sediments collected from four sites in the greater Tauranga Harbour. An elevated level of PCBs (19.9 ng g -1 ) was identified in a Waikareao Estuary sample. PCB and DDT levels of up to 24.1 ng g -1 and 5.38 ng grespectively, were subsequently detected in other eastern shore Waikareao Estuary sediment samples. Higher levels of PCBs (68.6 and 73.8 ng g -1 ) and DDTs (total 7.52 and 19.2 ng g -1 ) were detected in sediments from two eastern shore stormwater drains identified as the likely sources of the PCB and DDT burden entering the Waikareao Estuary. Black, carbonaceous, coal-and asphalt-like, paniculate material (98% loss of organic carbon on ignition), isolated by sieving a representative sediment sample, exhibited DDT and PCB levels which were respectively 85 and 6 times higher than was the case for other sieved fractions.

Heavy Metals and Organic Hydrocarbons in Sediments from the Waikareao Estuary, Tauranga Harbour, New Zealand

“…The data from Tables 1 and 2, and the organochlorine compound concentrations reported in Burggraaf et al 1994, were log-normalised prior to the derivation of the Pearson product-moment correlation matrix (Table 5). The correlation matrix shows that the organic compounds were highly (p<0.001) correlated.…”

“…Replicate analysis of five subsamples of the same sediment sample gave relative standard deviations of 4.7%, 5.4%, 3.3% and 7.8% for Pb, Cu, Zn and Cd respectively. Sediment material (40 g) was dried, Soxhlet extracted, and prepared for combined gas chromatographic/mass spectrometric analysis (GC/MS) as described previously (Burggraaf et al 1994), other than that diethylnaphthalene (added to the extracts, prior to florisil column chromatography) was utilised as the internal standard. Aliphatic, aromatic and triterpene hydrocarbons were quantified using a Hewlett Packard (HP) 5890 GC instrument fitted with a HP 7636A automatic injector and a DB-1 (J & W Ltd) fused silica capillary column (15 m x 0.25 mm), interfaced to a HP 5970B mass selective detector (MSD).…”

Organochlorine Compounds in Three Species of Shellfish from Waikareao Estuary, Tauranga Harbour, New Zealand

“…Additional sediment data was obtained from site W5' for PCB congeners 101, 110, 151, 149, 153, 138, 187, 180 and 170 (1.0, 0.7, 0.7, 2.1, 3.2, 2.4, 0.8, 1.5 and 0.9 ng/g respectively), p,p'-DDT (not detected), p,p'-DDD (0.3 ng/g), p,p'-DDE (0.5 ng/g), technical chlordane (trace) and dieldrin (trace) using a previously reported method (Burggraaf et al 1994). Table 1.…”

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Biota species were collected in February 1992 from the Waikareao Estuary, according to availability, from the ten sampling stations (Figure 1) utilised in an earlier the sediment study (Burggraaf et al 1994). The species examined were: Macomona liliana (wedge shell), a surface deposit feeder that resides at depths of up to 10 cm and feeds by means of an inhalant siphon extending to the surface, Saccostrea glomerata (New Zealand rock oyster) that feeds by filtering suspended particles from the water column, and Amphibola crenata (mud snail) a deposit feeder that feeds on micro-organisms and organic detritus at the sediment surface.

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“…The first 1 mL of eluent consisted predominantly of fatty substances, while OCC species (PCBs, DDTs, chlordanes, etc) were present in the next 4 mL of eluent. GC conditions and quantification procedures were as reported previously (Burggraaf et al 1994) for the corresponding sediment samples, other than that the detection limits were 8-10 ng/g lipid weight for PCB congeners, p,p '-DDE, p,p '-DDD, chlordane isomers and dieldrin, and 16-20 ng/g for p,p'-DDT. Elution with light petroleum ether (30 mL), and 1:19 light petroleum ether-ether (15 mL) afforded fractions A and B respectively.…”