Biotechnology and Waste - Environmental Biotechnology: Theory and Application - page 178

The question of methane production, so central to the original thrust of the
legislation has been addressed by requiring sites to collect the landfill gas pro-
duced and use it for energy generation, conceding that it may be flared off where
for some reason this is not possible.
A second potential environmental problem typically associated with landfills
is the production of polluting leachates, which can be aggravated by the dumping
of biowaste. Water percolating through the site tends to leach out both organic
and inorganic substances which can lead to contamination of the groundwater.
The persistence of pathogens and the potential translocation of many biologi-
cally active chemicals have become of increasing concern over the last 10-15
years in the light of growing (though still largely circumstantial) evidence of
health problems associated with proximity to certain landfill sites. However,
there is considerable variance between many aspects of different facilities and,
additionally, much uncertainty as to the extent of any possible exposure to chem-
icals found therein (Vrijheid, 2000). The UK Government commissioned what
arguably remains the world's most extensive study to date into the potential
health risks of living within 2 km of landfills, to examine the incidence of low
birth weight, congenital defects, stillbirths and cancers in the vicinity of 9565
landfill sites, with a sample size in excess of some 8 million pregnancies. This
revealed a 7% increase in the rate of both chromosomal and non-chromosomal
birth defects (Elliott et al ., 2001) but the expert advisory committee observed that
this represented only a small excess risk and might well be accounted for by fac-
tors other than those directly attributable to landfill itself. While domestic landfill
operations, then, may well be of little significant threat to those around them,
the situation for hazardous waste sites, though admittedly less well investigated,
appears somewhat different.
The findings of the later investigation (Vrijheid et al ., 2002) of data originat-
ing from a smaller study of certain European landfills which accept hazardous
waste (Dolk et al ., 1998) suggests a 40% increase in chromosomal birth defects
and a 33% increase in the risk of non-chromosomal abnormalities, within a
3 km radius. However, whether the observed increase in risk arises merely from
living near such a hazardous waste site, or as a result of other factors as yet
unknown, remained unclear. Subsequently, a 2006 study into the health con-
cerns of residents neighbouring an industrial landfill in Melbourne, Australia
failed to identify any difference in the occurrence of cancers, birth defects or
other birth-related outcomes between those living in the area and the rest of
the state. It did note a small but statistically significant increase in pre-term
births (defined as < 37 weeks gestation) but since this fitted with a more gen-
eral regional pattern, socio-demographic influences were cited as the most likely
influence (Lynch et al ., 2006). Clearly, understanding the true scope of landfill
releases, their potential toxicity, the possible exposure pathways and how other
environmental or demographic factors inter-react with them to influence health
is - and will remain - essential in interpreting any epidemiological data.
Even where there is nothing to suggest an adverse effect on the local popula-
tion, high concentrations of biowaste-derived leachate remain undesirable. Such