Executive summary Waste Remediation Services Ltd (WRS) operates a drilling waste landfarm (Waikaikai Landfarm) located off Lower Manutahi Road at Manutahi, South Taranaki, in the Mangaroa catchment. This report for the period July 2016 to June 2017 describes the monitoring programme implemented by the Taranaki Regional Council (the Council) to assess WRS’s environmental and consent compliance performance during the period under review. The report also details the results of the monitoring undertaken and assesses the environmental effects of their activities. WRS holds one resource consent, which includes a total of 32 conditions setting out the requirements that they must satisfy. In this monitoring period a small amount of material was landfarmed. This material comprised the stored drilling material within the last unlined drilling storage cell in Taranaki. The site also acted as contingency storage for the consent holder’s other landfarm at Symes, Manawapou. All landfarmed areas were submitted for surrender analysis at the end of the monitoring period. The resultant analysis indicated that the areas utilised for the practice of landfarming had generally met their conditional limit for surrender with only one parameter above the surrender limit. Sodium concentrations within the soil were elevated above the conditional surrender limit of 460 mg/kg, with the most elevated concentration at 550 mg/kg. All other analytes were below their limit as specified by the consent. The rationale for allowing the areas to be surrendered, despite the elevated sodium concentrations, was due to the observations undertaken by the Council of the long term analysis of the sodium absorption ratio (SAR). The long term record indicated that the SAR had remained stable below four (
