Shellfish Contaminants Programme - Waikato Regional Council

Currently this is a data set of the concentration of metals (cadmium, copper, lead, mercury and zinc) found in the green-lipped mussel (Perna canaliculus) at 15 selected sites within the coastal marine area of the Waikato Region. Purpose: The data set is intended to indicate the state of the environment, and to assess the significance of contaminant levels for public health and ecosystem protection.

This data set is currently limited to a report (Coffey, 1994) documenting the distribution of green-lipped mussels (Perna canaliculus) within the coastal marine area of the Waikato Region and assessing their suitability as a bioassay organism. A report has also been written on heavy metal contamination in feral mussels from 15 sites around the Waikato Region (Coffey et al., 1996).

15 locations in the Waikato Region (east and west coast).

Marakopa (NZMS 260-R16 596193), Kawhia (NZMS 260-R15 659445), Raglan (NZMS 260-R14 747769), Port Waikato (NZMS 260-R13 613210), Thames (NZMS 260-T12 439 959), Te Puru (NZMS 260-T12 344600), Coromandel (NZMS 260-T11 279853), Channel Island (NZMS 260-T10 and U10 439959), Port Charles (NZMS 260-T10 and U10 320195), Mercury Islands (NZMS 260-T10 and U10 567096), Whangapoua (NZMS 260-T10 and U10 439959), Ohinau’s (NZMS 260-T10 and U10 649949), Whitianga (NZMS 260-T11 521817), Tairua (NZMS 260-T11 641618), Whangamata (NZMS 260-T12 677382).

Sampling was undertaken January-March 1996.

From each site a sample sufficient to yield 50 g of flesh weight was hand-collected 9an average of 15-30 mussels per site). Care was taken to collect samples of similar size, shape and condition. Mussels were placed in clean, labeled 10 l plastic buckets – 1 site per bucket – filled with fresh seawater collected from each site. The buckets were kept cool during transport to the laboratory. In the laboratory, encrusting organisms were removed from the external shell of each mussel using a stainless steel knife. Each sample was then placed in an aerated composite seawater mix with a specific gravity of 1.022 for a 12-hour depuration period. Aseptic conditions were applied for all subsequent handling and processing of samples. Each mussel in each sample was measured (length, width, height), weighed (whole intact shell) and shucked with a stainless steel knife. All soft tissue was removed from the shell and “towel dried” with clean tissues to absorb free surface moisture form the sample. Flesh was wet-weighed and transferred to a composite sample form which 3 replicate samples of at least 50 g of wet flesh were taken for analysis. Replicate samples for each site were placed in sterile jars, sealed, labeled and frozen prior to analysis. Additional samples were collected from the Thames site for dissection into selected organ types (gut, adductor muscle, viscera, kidney and shell). These samples were collected and processed as described above, with the exception that following shucking, individual mussels were dissected to provide 3 replicate organ sample of at least 50 g of wet flesh. Wet flesh was analysed for cadmium, copper, lead and zinc (following digestion in nitric acid/hydrogen peroxide in a high pressure microwave – USEPA method 3051) using flame and graphite furnace atomic absorption spectroscopy (APHA 311 and 3113B). Wet flesh was analysed for mercury using cold vapour atomic absorption spectroscopy (APHA 3112B, modified). Analytical results are presented as milligrams of element per kilogram wet flesh weight. Further information on methodology is available in Coffey et al. (1996).

The 1996 survey has been completed; no further sampling as part of this programme has been undertaken. Data quality: Unknown – but note that standard analytical procedures were adhered to. Completeness: Sampling restricted to one species, samples collected from 15 sites on one sampling occasion in summer 1996.

Written reports. Digital Format: n/a

No confidentiality.

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