76 



These three studies confirm earlier observations by the National Research Council (1983) and other reviewers 

 that the MMS is correct in its strategy to emphasize development and production sites rather than exploration, 

 except in unique environments, and to look further into water column impact studies such as preoccupied our 

 interests early on. 



One very interesting study by Thompson et al. (1989) on the effects of drilling wastes offshore Florida in the Big 

 Bend seagrass bed area did find significant effects on Halophila from an exploratory rig. They postulated that 

 physical smothering and decreased light penetration may have been the underlying mechanisms. Fortunately, 

 they revisited the site some two years later and found recolonization by the seagrass in affected areas. This 

 brings up the interesting question of recovery rates and mechanisms for recovery. It may be most useful for 

 MMS to focus on understanding the natural recovery mechanisms and rates as well as detecting areas of impact. 

 I recommend again that the workshop incorporate these ideas for discussion. 



Many papers addressed both diesel and mineral oil contaminated cuttings and drill solids in international waters: 

 Beaufort Sea (Erickson et al. 1989); the North Sea (Reierson et al. 1989; Bakke et al. 1989a and b; Grahl- 

 Nielsen et al. 1989); and the Canadian offshore in general (Chenard et al. 1989). These field studies found that 

 hydrocarbons were degraded through time by microbial and weathering mechanisms and that the degradation 

 rate was largely an inverse function of hydrocarbon concentration, composition (high or low aromatic content), 

 and environmental factors (e.g., temperature, nutrients). Erickson et al. (1989) did find that low molecular 

 weight ispoprenoids, as detected by GC fingerprinting, were particularly useful to follow the fate of a specific 

 mineral oil (VISTA ODC), which is widely used, along with other mineral oils, in the Gulf of Mexico. This study 

 emphasizes the importance of monitoring the right parameter to determine fate. I would like to point out that 

 due to the increased drilling of deviated holes in the Gulf of Mexico as platforms have more welis to develop 

 a field, the use of mineral oil lubricants and spotting fluids may increase during the projected MMS timeframe. 

 U.S. Environmental Protection Agency (EPA) toxicity restrictions and sheen prohibitions are strong motivators 

 to find substitute products for oils, but few completely hydrocarbon-free product substitutes have reached the 

 market at this time. 



The Erickson study (1989), as well as the study by Sauer et al. (1989), focused on organic components of drilling 

 wastes rather than inorganics. Sauer was interested in using the most prevalent organic constituent of muds, 

 lignosulfonate, as a possible tracer. Organic constituents may behave somewhat differently than barium in areal 

 distribution and eventual fate because of significant differences in specific gravity (i.e., >4.2 for barite,_< 1.0 for 

 most organics). Sauer found that lignosulfonate components could be useful as organic tracers, depending on 

 the background ambient levels of lignin-type compounds. 



The subject of organic constituents of drilling wastes is an area for discussion or consideration by this group for 

 several reasons. First, the frequency and total amount of organics, particularly polymeric compounds such as 

 polyacrylates, polyacrylamides, and biopolymers, are increasing to become a far more significant part of the 

 waste. The need for inhibitive systems as industry drills through unstable shales, particularly in the Gulf of 

 Mexico, and the considerable problem of using traditional potassium based systems due to EPA toxicity 

 regulations, is putting increased emphasis on polymers. While these various types of polymers are typically of 

 low toxicity, they may cause some changes in mud dispersion. Some of the newer polymer systems have the 

 consistency of liquid "silly putty" with potentially different dispersion behavior. These polymers may be potential 

 new tracers also as we look for key parameters to monitor. An important point to make is that EPA is 

 consistently showing more interest in the organic constituents of drilling fluids as evidenced by the onshore 

 drilling waste study which monitored for 229 organic compounds, 29 elements, and 22 conventional analytes 

 (DeNagy and Telliard 1989). 



One paper concerning organic contamination of the North Sea, based on a 14 year long-term review and study, 

 had specific suggestions for what should be the key components of a six year long-term monitoring. Ricrerson 

 et al. (1989), which is noted by the editors as being controversial in nature, conclude with a biological and 

 chemical list of parameters that should be monitored with a schedule for monitoring based on North Sea 

 degradation rates for oil contaminated sediments. I recommend that the workshop review Reierson critically to 

 see if any of their long-term monitoring suggestions are relevant to MMS studies. 



