Nurdles collected (between May-Jun 2013) and sent to pelletwatch.org
Collection sites
Takapuna site @-36.792585667079706,174.77987408638
Tamaki site @-36.90542586353609,174.87586833536625
Tamaki site @-36.90542586353609,174.87586833536625
South Down site @-36.929860119275695,174.8261260986328
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REPORT
Due to the close proximity of the samples, we have chosen 2 out of the 4 samples you sent us based on location and plastic pellet conditions.
PCBs
PCBs are industrial and electronic chemicals, which has been banned from use in the late 70’s to 80’s. However, this chemical can still persist in the environment. We observed moderately high concentration in Southdown with 157 ng/g-pellet which coincides with a previously analyzed sample in Auckland (Browns Bay) with 65 ng/g-pellet also categorized moderately polluted (refer to PCBs NZ) However, Pakuranga, which is on the other side of the bay shows low concentration with 9.8 ng/g-pellet (rounded up to 10 ng/g-pellet in the maps) which can be categories as non-locally polluted. This could be due to the nature of the sampling sites where Southdown is an industrial area compared to Pakuranga which is more of a residential area. Compared to global concentration (refer to PCBs world) pollution status in New Zealand is moderate to low. Red spots in the global map show extremely polluted hotspots.
DDTs
A similar trend is observed with DDTs, which are pesticides also no longer in use. Southdown shows higher concentration with 11ng/g-pellet compared to Pakuranga with only 3 ng/g-pellet. In comparison with developing countries (refer to DDTs world) where DDTs were used for vector control, DDTs concentration in your samples are categories as lightly polluted and non-locally polluted for Southdown and Pakuranga respectively.
HCHs
As for HCHs, which is also a pesticide no longer in use, concentrations were low for both sites with 0.2 ng/g-pellet and 1 ng/g-pellet for Southdown and Pakuranga respectively which coincides with Browns Bay, 0.4 ng/g-pellet (Refer to HCHs NZ) suggesting no recent usage of the pesticide. However, from the same map you can observe high concentrations of HCHs north of the island (Taupo Bay and Ahipara). These seem to be agricultural sites, which may still be using the pesticide Lindane.
PAHs
Lastly, PAHs which are found in petroleum or crude oil products and combustion products generated from combusting fossil fuel and biomass, concentrations were low for both sites with 405 ng/g-pellet and 247 ng/g-pellet. These can be considered background levels mostly from combustion such as vehicle exhaust and power plant followed by atmospheric transport. From the global map of PAHs (refer to PAHs global), extremely high concentration of PAHs can be observed from the other areas in New Zealand. That is an example of oil pollution from the Rena oil spill case off the coast of Tauranga in Oct 2011.
So… Looks like we are ok for Pesticides (DDTs and HCHs) and PAHs. The PCBs in Southdown worry me. I will look further into that. It’s horrible that the ocean is full of these little poison pills, I am glad the ones I collected will not end up in any fish or birds.