89
Technical Papers
Table 1. Standards for maximum concentrations of organic contaminants in sewage sludge mg kg-1 dw; except PCDD/Fs ng WHO05 TEQ kg-1 dw. AOX
DEHP
LAS
NP/NPE
PAH
∑DDT 1 OCPs 1B
Australia Austria
500
Czechoslovakia
500
Denmark EC (2000)A
OCPs
500
EC (2003)A
6
PCBs
‘Dioxins’
0.5-1
50
0.2 -1
50 - 100
Other
0.6 50
1300
10
3C
100
2600
50
6C
0.8D
100
5000
450
6C
0.8D
100
Fluoranthene: 4 Benzo(b)fluoranthene: 2.5 Benzo(a)pyrene: 1.5
0.8D
France
Germany Current (2002)
500
Benzo(a)pyrene: 1
Proposed (2007)
400
Benzo(a)pyrene: 1
0.1E
3C
0.4D
Sweden
50
0.1E
100
30
MBT+OBT F: 0.6 Tonalid: 15 Galaxolide: 10
Proposed but withdrawn and basis subject to review Individually applied to aldrin, chlordane, dieldrin, heptachlor (and the epoxide), hexachlorobenzene and lindane Sum of 9 congeners: acenapthene, fluorene, phenanthrene, fluoranthene, pyrene, benzo(b+j+k)fluoranthene, benzo(a)pyrene, benzo(ghi)perylene, indeno(1,2,3-c,d)pyrene. D Sum of 7 congeners: PCB 28, 52, 101, 118, 138, 153, 180 E Sum of 6 congeners: PCB 28, 52, 101, 138, 153, 180 F MBT - Mercaptobenzothiazole; OBT - 2-hydroxybenzothiazole References: (EPCEU, 1986; European Commission, 2001; Eriksen et al., 2009) A B
C
the human body, including Australians (Kärrman et al., 2006), with long half-lives in the human body of 2–9 years (Olsen et al., 2007), as well as being extremely persistent in the environment (e.g., the two most common PFCs, PFOA and PFOS, have environmental half-lives in water of >92 years and >41 years respectively (USEPA, 2014).
There are a number of examples where PFC contaminated waste was
The reported problems extend further. Unlike other persistent organic
pollutants that are often highly lipophilic (fat-loving), studies have shown because PFCs are water-soluble, their ability to transfer from the soil matrix into the plant material (the biotransfer factor) is high for potato, carrot and cucumber and cereal crops (Stahl et al., 2009; Lechner & Knapp, 2011). This transfer from ‘soils to crops’ provides a plausible explanation for the presence of PFCs in plant-based food stuffs (Noorlander et al., 2011). While PFCs are not normally present in dairy samples, they were present in dairy milk samples collected from the Decatur region of Alabama (Young et al., 2012) and in Japanese farmland animals (Guruge et al., 2008). This case study illustrates what can happen if new potential pollutants are not being monitored or regulated. Of even more concern is that land application of these fluorinatedcontaminated biosolids is compliant with Australian biosolids regulations, demonstrating a deficiency in Australian regulatory practice. Furthermore, without altered regulatory practices it is entirely possible that similar contamination incidents will continue. The German and USA incidents occurred following the use of organic material on land, and
SEPTEMBER 2014 WATER
BIOSOLIDS MANAGEMENT
Human exposure to PFCs is thought to typically occur through the diet and includes fish (Noorlander et al., 2011), plant-based products and meat (Guruge et al., 2008), as well as potable water (Quiñones & Snyder, 2009). PFCs can act as development and reproductive toxicants (Kim et al., 2013), and have been associated with lowered birth weight and increased mortality in laboratory rat studies (Pinney et al., 2014) and decreased human sperm counts (Joensen et al., 2009). Unfortunately, modern wastewater treatment processes will not degrade most PFCs, and they will normally be released into the environment via the treated effluent and/or biosolids (Boulanger et al., 2005) creating a challenging management issue.
applied to land with serious negative impacts. One of the most notorious examples is Decatur, Alabama, USA, where biosolids contaminated with high levels of PFCs from the trade waste of fluorinated chemicals manufacturers, chemical users and landfill leachates were applied to agricultural land for over 10 years, polluting the local groundwater supplies (Renner, 2009). From a total of 51 groundwater well samples, 25% exceeded the USEPA’s health-based advisory limit for the PFC contaminant (Renner, 2009; USEPA, 2009a). This is not an isolated case. Industrial waste with high concentrations of PFCs incorporated into a soil improver by a recycling company and sold to farmers in Sauerland, Germany, caused substantial environmental pollution (Wilhelm et al., 2008). One town of 50,000 had its drinking water supply contaminated at levels greater than the USEPA’s healthbased advisory limit, which resulted in elevated body concentrations of PFCs 4–8 times higher than control populations, even a year after the exposure through drinking water had ceased (Hölzer et al., 2009).