LEEDS CITY COUNCIL, CONTAMINATED LAND CONSULTATION RESPONSE
Information for planning officer
Application Ref:
P/14/06808/FU
To:
Land at Tyersal Lane, Tyersal - Erection of 283 dwellings and associated
infrastructure
Ian Cyhanko
From: Brad Hall
Our Ref:
PCL01139_14_06808_PRD1
Site & Proposal:
Date:
10/12/2014
ACTION FOR PLANNING OFFICER
More information needed before determination. No objections in principle.
Additional
I have reviewed the information submitted in support of the application.
information
Please ask the applicant to address the following comments:
required:
(for planner to
1. Please justify why assessment criteria based on 6% SOM have
copy and paste to
been used for PAHs, when SOM does not appear to have been
applicant)
included in the testing schedule? Would a more conservative
approach not be more appropriate?
Assessment criteria based on 6% SOM have only been applied to
the topsoil samples where at least 6% is assumed to be present
due to the high proportion of organic matter usually found in topsoil.
For the samples of natural ground and the sample of made ground,
assessment criteria based on 1% SOM have been used. Even if
the PAH results for the topsoil were assessed using the 1% SOM
criteria, the modified mean and overall conclusion would remain the
same. Similarly with the sample of made ground, where a BaP
concentration of 15 mg/kg was recorded. This exceeds both the 1%
and 6% SOM criteria.
We note that the S4UL for benzo(a)pyrene is 2.2 mg/kg for 1%
SOM.
2. Further justification is required in relation to benzo(a)pyrene. Why,
is it considered suitable for gardens when 7 out of 10 topsoil results
are over the assessment criteria used (and 9 out of 10 when a
more conservative approach is used)? Consider alternative
assessment criteria, site specific assessment criteria and additional
statistical analysis.
The site is Greenfield. Excluding the outlying result recorded from
TP15, a BaP modified mean of 2 mg/kg is calculated, alongside an
arithmetic mean of 1.5 mg/kg. The majority of the results show a
range of concentrations between 0.8 and 1.5 mg/kg, which are
either less than the 0.83 mg/kg assessment value or less than two
times the value.
This is however, now considered to be superseded by the most
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conservative S4UL of 2.2 mg/kg.
3. Please include more discussion of naphthalene. What is the
breakdown of exposure pathway contributions, why will it not be
beneath proposed buildings, why will organic material in topsoil
breakdown the hydrocarbons over time?
If using the most conservative S4UL 1% SOM value of 2.3 mg/kg,
naphthalene was only recorded to be elevated in one sample of
topsoil (TP15 0.1) with a concentration of 14 mg/kg. The sample
did not record any visible signs of material such as ash that could
account for the elevated concentrations.
We advised in our Phase 2 report that further testing should be
carried out around this trial pit.
4. Please confirm what is meant by ‘more onerous’ when discussing
PAHs and include all elevated contaminant concentrations
including discussion as to why they are not considered significant.
Benzo(a)pyrene is considered appropriate to use as a marker, as it
the most toxic of the PAHs, whilst Naphthalene is also considered
as it is the most volatile. All PAHs are compared to the assessment
concentrations and if several are elevated the risk assessment
considers these to cover all of the PAHs.
5. The elevated concentrations of lead have not been discussed.
Please amend accordingly.
At the time of compiling the Phase 2 report, concentrations of lead
were recorded at or below the accepted SGV at the time i.e.
450 mg/kg.
Using the new S4UL of 200 mg/kg, one sample of topsoil from TP7
recorded a lead concentration of 230 mg/kg. A corrected mean for
these all ten lead concentrations is calculated to be 172 mg/kg,
which is less than the S4UL. The slightly elevated lead
concentration recorded in TP7 is therefore not considered to pose a
significant risk to human health.
6. The assessment criteria used for chromium in the report does not
correspond with the value in Appendix 3. Please amend
accordingly.
We apologise for this error. One sample of natural ground recorded
a chromium concentration of 410 mg/kg. Chromium occurs in two
forms; the less toxic trivalent chromium and the more toxic
hexavalent chromium. Since the hexavalent concentration for this
sample was less than 0.5 mg/kg, the remaining chromium can be
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considered to be in the trivalent form. The S4UL for Chromium III is
910 mg/kg. Since the concentration of 427 mg/kg is significantly
lower than the S4UL, chromium is not considered to pose a
significant risk to human health.
7. Please submit the background workings for the statistical analysis
undertaken.
Please find attached the excel spreadsheets for the modified and
corrected means.
8. The Phase 2 Report indicates that further contamination
assessment works are required. Please ask the applicant to submit
the results/ reports from these works and a Remediation Statement
prior to determination.
This will be prepared in due course.
Applicant advised
to consult:
(for planner to
advise applicant)
Information
reviewed:
Please note:
Yorkshire Water
Reason: To ensure that appropriate services are provided at the site
Environment Agency Waste Management Licensing Section
Reason: To ensure requirements of Waste Management Regulations are
met
ADDITIONAL SUPPORTING INFORMATION
Title: Phase 1 Geotechnical and Geo-environmental Site Investigation
Preparation date: Jan 2014
Prepared by: Eastwood & Partners
Report ref: 36738-001
Title: Phase 2 Geotechnical and Geo-environmental Site Investigation
Preparation date: June 2014
Prepared by: Eastwood & Partners
Report ref: 36738-002
Geotechnical issues have not been considered or reviewed as this is not
within the remit of the Contaminated Land team.
If this application is to be refused, please DO NOT include contamination
as a reason without consulting us.
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The following pages are summary information for Leeds City Council information only. This
information should not be relied upon by third parties.
WHAT DO WE KNOW ABOUT THE SITE?
Previous
On Site: Agricultural/ recreational land
contaminative use
Off Site: Railway line, landfill, quarries, worsted mill
Environmental
Geology: boulder clay overlying PLCM
Setting
Hydrogeology: Secondary A
Hydrology: 430m east
Mining: The site is not within the likely zone of influence, no mine entries
however shallow coal exits
Landfill: one SW of site (Bradford Council) CS255 and 276 adjacent to the
sites north western boundary. CS255 Foundry sand solid construction demo
waste, drums, paper wood paint solvents and garden wastes also disposed
of, elevated CH4 of 34% in 1988, 60% LEL 1995. CS276 disposal of solid
inert and non-flam industrial construction and demo waste, ceased in 1982.
Radon: Not affected Max LEL 1.8% 1996.
Proposed
Erection of 283 dwellings and associated infrastructure
Development
Development
Layout plan?
y
Site boundary plan?
Y
Site Area (ha)
9.5
Grid Reference
419487 432024
Existing PCL
Y
Site visit undertaken?
No
Adjacent PCLs?
No
Previous reports
submitted?
Consultation ID
No
12289
SUMMARY OF WORKS UNDERTAKEN / PROPOSED &
REPORT FINDINGS/RECOMMENDATIONS.
Phase 1
Phase 1 identifies former land use as predominantly agricultural with
Geotechnical and limited recreational use on site. Adjacent historical land uses identified as
Georailway line, landfill, quarries and worsted mill.
environmental
Site Investigation, The site is part underlain by boulder clay (NW) which is subsequently
Jan 2014 – 36738- underlain by PLCM which are classified as a Secondary A Aquifer.
001
Two landfills are located adjacent to the sites NW boundary and one is
located to the SW.
Potential contaminative land uses within the vicinity include engine
components manufacturer, refrigeration, gas supplies, salvage dealers.
Potential contaminants include heavy metals, PAHs and ground gas.
Potential pathways identified as ingestion, inhalation and dermal with
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potential receptors including future residents, construction workers and
controlled waters.
Proposed SI to include for gas monitoring to assess migratory ground
gases and analysis of soil samples through the excavation of trial pits and
boreholes.
Phase 2
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