General

Seafood quality depends on both the environment in which the species lives and its treatment after harvesting. In general Australia's seafoods are low in contaminants but some species accumulate heavy metals, biotoxins, microbes and pollutant chemicals. Organochlorine pesticides such as DDT and DDE are widely present in low concentrations and polychlorinated biphynls (PCBs) and dioxins have been found in fish in low concentrations. The sources of these contaminants need to be managed to minimise the risk to aquatic organisms in general and to ensure contaminant concentrations in the flesh of seafood species remain very low. The Australian fishing industry produces more than 220,000 tons of seafood a year, valued at over $2.4 billion (fish $861 million, crustaceans $985 million, molluscs $538 million, other products $23 million). The NSW seafood industry contributes more than $500 million to this economy.

Key Issues

The major issue is the accumulation of contaminants in the flesh of seafood species. Heavy metals such as mercury, cadmium and lead can be accumulated either naturally from seawater, through the food-chain, or by species inhabiting locally contaminated areas. Levels become elevated in the top-level predators such as fish. Micro-algae produce biotoxins that can accumulate in fish that graze on algae and in filter-feeding shellfish. Stormwater, sewage and industrial discharges are the main sources of concern. Sewage wastes from outflows have contaminated cultivated oyster crops and caused bacterial and viral contamination of shellfish. Stormwater run-off introduces contaminants that become chemically bound to fine sediments and are released later as a result of disturbance or changes in water chemistry. Disease-causing pathogens also survive longer between sediment grains than in water. Heavy metals, hydrocarbons and organochlorine compounds all have a strong affinity with sediments and can be accumulated via the food-chain. Heavy metals accumulate in the food-chain through fish, molluscs, algae and seagrass.

Protocols

The ANZECC & ARMCANZ Guidelines (2000) for the protection of human consumers of fish, crustaceans and shellfish focus on inorganic and organic chemical toxicants (heavy metals, pesticides, etc), radioactive elements, bacterial and viral contaminants, parasites and natural toxins (micr-algae and natural fish poisons). Some chemical compounds at certain concentrations cause tainting of the flesh of fish and other seafood species; these reduce palatability and can adversely impact on the fishing and harvesting industries.

Core protocols are those for the following indicators:

Algal blooms
Algal species density and diversity
Bacteria monitoring
Bioaccumulation
Fish kills
Physical and chemical
Protozoan monitoring
Shellfish

Supplementary protocols / information relate to:

Acid sulphate soils
Aquatic ecosystem health
Bioaccumulation
Chlorophyll a
Desktop monitoring using satellite data
Diatom monitoring
Groundwater
Metals in sediments
Metals in water
Oil and other spills
On-site sewage monitoring
Pesticides and herbicides
Primary productivity
Profiling
Real time Chlorophyll monitoring
Salinity
Urban stormwater

Contacts - Core Agencies

• Safe Food Production NSW licence shellfish producers and seafood businesses. They developed the Seafood Safety Scheme which sets standards for production, processing, wholesaling and distribution of seafood for human consumption and have responsibility for the shellfish quality assurance program established under the Fisheries Management Act 1994 and the NSW Fisheries Management (Aquaculture) Regulation 1995. This involves monitoring heavy metal and microbial contaminants in both shellfish meat and the waters surrounding aquaculture farms. SafeFood also provide training to commercial fishers in food safety handling standards.
• NSWHealth inspectors cover the retail and food service sectors; the Director-General has the power to prohibit the cultivation, harvest or obtaining of any food and to require the recall, impounding or destruction of any food under the Food Act 1989. They also have emergency powers under the Public Health Act 1991.

Other organisations involved

• NSW Fisheries is responsible for the management of fisheries resources, marine vegetation and fish habitat; they oversee the harvesting of fish, crustaceans and molluscs from estuaries and ocean waters.
• Agriculture, Fisheries and Forestry Australia undertake the National Residue Survey program collecting data on levels of residues and compliance with standards, and also testing animal and plant food products for chemical residues and environmental contaminants such as heavy metals.
• Australia New Zealand Food Authority (ANZFA) sets the maximum permitted limits to contaminants for seafood consumption. The standards are listed in the Food Standards Code (ANZFA 1996), are regularly updated and are enforceable through legislation.

Case Studies