Investigation of chemicals released by the Vinythai and Thai Plastic & Chemicals (TPC) PVC manufacturing facilities, Map Ta Phut Industrial Estate, Rayong Province, Thailand
By Kevin Brigden, Iryna Labunska & David Santillo : Greenpeace Research Laboratories, Technical Note 09/2004
Vinythai and Thai Plastic & Chemicals (TPC) operate separate polyvinyl chloride (PVC) manufacturing facilities within the Map Ta Phut Industrial Estate, located in Rayong Province on the Eastern Seaboard of Thailand. Canals flow through the estate and receive discharged wastewaters from many facilities prior to discharging into the Gulf of Thailand. Both PVC manufacturing facilities discharge wastewaters to one of these canals herein referred to as the east canal. Within the Vinythai and TPC facilities, PVC is produced as well as the raw materials used in its manufacture, namely chlorine, ethylene dichloride (EDC) and vinyl chloride monomer (VCM).
In May 2003 Greenpeace collected samples of wastewaters from Vinythai and TPC at their point of discharge to the east canal, as well as sediments from this canal. All were analysed for a range of heavy metals and organic chemicals.
Discharged effluents from both Vinythai and TPC contained a diversity of chlorinated volatile organic compounds (VOCs) that possess a range of toxic characteristics. Many VOCs were common to discharges from both facilities, though all VOCs in Vinythai effluents were present only at low concentrations. The main TPC discharge (AT03032) contained more chlorinated compounds than all other discharges from either facility. Most significant was the presence of 1,2-dichloroethane (EDC) at 250 ug/l, a level that, if representative of continuous discharges, would be unacceptable for an equivalent plant in the USA. EDC is not highly persistent in the environment but is, however, toxic to humans and animals. The main TPC discharge also contained other organic chemicals including 2,4,6-trichlorophenol, a less volatile organochlorine, and DEHP, a phthalate ester widely used as a PVC additive and which is relatively persistent and toxic to reproduction.
VOCs may be readily lost to the air during production, storage, transfer and use, or from wastewaters during their treatment or discharge. Emissions to atmosphere via these additional release routes may be very significant for such volatile compounds but determination of such releases was not feasible in the current study.
The effluents from both facilities also contained some heavy metals at concentrations above background levels expected for uncontaminated surface waters, though the levels in Vinythai discharges were only slightly elevated above these levels. In contrast, two of the discharges from TPC contained high levels of zinc, with a concentration of 1590 ug/l in the main discharge (AT03032) and even higher in one other discharge (AT03030; 3020 ug/l). Zinc compounds are widely used as stabilisers in PVC formulations, and such use by TPC is a possible source of zinc to these wastewaters.
Analysis of sediments collected from the east canal yielded evidence for the discharge of heavy metals and organic chemicals over longer timeframes. Neither chlorinated compounds nor high concentrations of metals were found in sediment collected from the east canal upstream of both PVC manufacturing facilities. However, sediment collected by Vinythai’s middle discharge (AT03026) contained metals at somewhat higher concentrations than those found upstream. Moreover, sediments collected adjacent to the TPC discharges contained far higher concentrations, particularly for zinc, which was present at levels more than 80 times higher than background near the most contaminated discharge (AT03031), and over 8 times background concentrations by the main TPC discharge (AT03033).
The sediment samples associated with TPC discharges also contained the phthalate ester DEHP. Furthermore, a number of highly chlorinated compounds (octachlorostyrene and chlorinated benzenes) were also identified in these sediments, though at trace levels. These chlorinated compounds, though not identified in TPC effluents at the time of sampling, can be formed as by-products of industrial processes involving chlorine compounds. They are highly persistent in the environment and many are able to accumulate in the bodies of animals and humans, particularly the higher chlorinated pentachlorobenzene and hexachlorobenzene (HCB). These chlorinated compounds exhibit a range of toxic effects in humans and animals.
The presence within canal sediments of organic pollutants and elevated concentrations metals that were also found in discharged wastewaters indicates their environmental accumulation as a result of ongoing discharges. The identification of additional organochlorines in sediments associated with TPC suggests these have been released from this facility at other times. As many of these contaminants are environmentally persistent, their presence in the east canal suggests ongoing inputs to the Gulf of Thailand as waters and associated sediments are discharged.
Both Vinythai and TPC have policies intended to address environmental impacts resulting from manufacturing within their facilities, and TPC claim to employ monitoring and control programs to prevent contamination of the environment. On the basis of this study, it appears that the practical effect of these policies may be somewhat limited. PVC manufacturing, particularly at the TPC facility, is clearly a significant source of toxic VOCs to the surrounding environment.
The discharge of the organochlorines identified in the effluents is not specifically addressed under legislation addressing industrial effluents in Thailand, despite the Thai National Chemicals Management Profile listing organochlorine compounds as ‘specific chemicals creating concern’.
Greater controls are clearly needed to address the production of hazardous and toxic chemicals, be they intentionally or unintentionally produced, as well as their use and release. Stringent legislation addressing discharges and releases could be a first step, though protecting the environment and human health from such chemicals in complex waste streams will only be fully addressed through the progressive substitution of hazardous chemicals with non-hazardous alternatives. These measures are particularly needed for industries involved in the production and use of chlorinated chemicals, which use process that are widely associated with the formation of toxic and persistent chlorinated by-products.